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Wednesday, February 29, 2012

Potential for Another Significant Severe Weather Event March 2


The SPC has outlined another very large area of potential severe weather for March 2nd, only continuing to signal that spring has indeed sprung.

Discussion-
A 30% chance of severe weather on the Day 3 forecast is very concerning in my eyes. Frankly, I worry that this may very well end up like today, especially with the way the slight risk is angled in comparison to what has evolved today.
The 12z NAM is printing EHI values conductive for tornadoes to once again start in Oklahoma and Arkansas before moving into Tennessee/Kentucky and Indiana. This does mean that the threat may be slightly further north. There should not be much of a cap over the area that could prevent storms, so any that do fire would easily break any cap that would be present, as per the 12z NAM. Instability should be edging up around 2000 j/kg, which combined with moderately high EHI values, could easily make for a dangerous situation.
An even more concerning piece is the available shear, with SFC (surface) to 700mb level shear exceeding 50 knots, which is fairly high- about as high as what was forecasted for today. Shearing closer to the surface appears to be less of an issue, which would be a good thing for those fearful of tornadoes.
Helicity in general, not accounting for instability, will be pretty high and will be something to watch.

The GFS also appears to indicate something will be firing, but because the GFS is not equipped with the same indices as the NAM, I cannot determine if the GFS sees the threat better or worse than the NAM.

This whole deal is pretty eerie, as a lot of similar features appear to be coming extremely similarly together as they have with today's severe weather outbreak. This will certainly be interesting.

Here's my long range look at the tornado threat.

Any questions can be asked below.
-Andrew

EF-4 Tornado Hits Harrisburg, Illinois **6 DEATHS**

The NWS has indicated that an EF-4 Tornado was confirmed in Illinois from the severe storms that started yesterday and continue through today.

**6 DEATHS HAVE BEEN CONFIRMED**


***preliminary information only... assessment ongoing***

The following is an initial report in... from a damage assessment
ongoing for the city of Harrisburg in southern Illinois.

* Event date - Wednesday February 29 2012

* event time - 456 am CST

* event type - preliminary EF4 tornado

* event location - southern part of Harrisburg

* peak wind - estimated 170 mph

* average path width - estimated 200 yards

* discussion/damage - strip mall near wal Mart suffered major
damage. Additional information regarding damage... injuries and
fatalities will be added to this preliminary report... as will
path length. As of right now... the latest is 6 deaths have been
reported.

This is considered a continuous update post and will be updated as more info comes in.

Law Enforcement Warning (Highway Closure)- Duluth, Minnesota


WIC003-010200- BULLETIN - EAS ACTIVATION REQUESTEDLAW ENFORCEMENT WARNINGMINNESOTA EMERGENCY MANAGEMENT AGENCY DULUTH MINNESOTARELAYED BY NATIONAL WEATHER SERVICE DULUTH MN306 PM CST WED FEB 29 2012 THE FOLLOWING MESSAGE IS TRANSMITTED AT THE REQUEST OF THEASHLAND COUNTY SHERIFFS DEPARTMENT. THIS IS AN URGENT MESSAGE FROM THE ASHLAND COUNTY 911COMMUNICATIONS CENTER. U.S. HIGHWAY 2 IS DECLARED IMPASSABLE AND CLOSED BETWEEN SANBORNAVENUE AND STATE HIGHWAY 13 NORTH DUE TO EXTREME WEATHERCONDITIONS. MOTORISTS ARE TO USE THE DESIGNATED STATE HIGHWAY 137DETOUR. THE CLOSURE WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE.

Stearns, Kentucky TAKE COVER

This image depicts a possible tornado. If you are in Stearns, TAKE COVER!

A return to winter weather this weekend


A return to winter weather this weekend

The way the weather has shaped up this week in terms of mildness, you could have been easily fooled into thinking that winter was over for this year. However, I did clearly state only last Saturday that:

Even though it is set to turn milder once again as we head into the start of next week, I still feel that the remainder of February and into the start of spring could still bring a number of notable wintry blasts of cold and snow to the UK that the professional meteorologists are possibly underestimating (and as I originally forecast).

I also stated:

Although the periods of moderation are likely to be less brief than I had anticipated in my original calculations for this period.

So as we head into this weekend, it is set to turn colder and fairly unsettled across most parts of the UK. A number of weather fronts look set to bring a wintry mix of rain, sleet, snow and strong winds to the UK. Saturday will see a wintry mix pushing its way eastwards across the UK, before clearing some parts of eastern England later. This could offer some potentially heavy falls of snow across higher ground as the front approaches these parts, with the possibility of snow to some lower levels too. Another wintry mix of rain, sleet and snow looks set to initially move in across parts of western and southern England throughout Sunday. Sunday will also remain relatively cold and unsettled, with the potential for some further wintry showers in the north too.

No severe weather warnings have been issued, and the current Met Office outlook for this weekend states two lines of text, which currently read:

Met Office Outlook for Friday to Sunday:

On Friday, mostly mild and dry, but cloudy. Conditions this weekend will then turn less mild and more unsettled, with some rain spreading eastwards.
Updated: 0314 on Wed 29 Feb 2012

James Madden (UK Long Range Forecaster)
ExactaWeather.com
Published: Wednesday 29thFebruary 2012 (13:57) GMT
Content copyright © 2010-2012. Exacta Weather. All rights reserved.

Tornado Warning (Confirmed Tornado, Blown Transformers Seen)- PennyRile parkway, Kentucky


626 
WWUS53 KPAH 291245
SVSPAH

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
645 AM CST WED FEB 29 2012

KYC107-149-177-291300-
/O.CON.KPAH.TO.W.0022.000000T0000Z-120229T1300Z/
MCLEAN KY-MUHLENBERG KY-HOPKINS KY-
645 AM CST WED FEB 29 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL HOPKINS AND
SOUTHEASTERN MCLEAN COUNTIES IN NORTHWEST KENTUCKY...AND NORTHERN
MUHLENBERG COUNTY IN SOUTH CENTRAL KENTUCKY UNTIL 700 AM CST...

AT 640 AM CST...TRAINED WEATHER SPOTTERS REPORTED A TORNADO CROSSING 
THE PENNYRILE PARKWAY AT EXIT 44. BLOWN TRANSFORMERS WERE ALSO BEING 
REPORTED. THE TORNADO WAS MOVING EAST AT 55 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A TORNADO IS ON THE GROUND. TAKE COVER NOW. MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID
WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR OUTDOORS...MOVE TO THE
CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3715 8693 3725 8759 3742 8752 3744 8710
      3737 8709 3734 8713 3734 8710 3738 8708
      3737 8704 3735 8700 3727 8697 3726 8695
      3718 8689
TIME...MOT...LOC 1244Z 277DEG 48KT 3730 8740

$$

Tornado Warning (Tracking Confirmed Tornado)- Santa Claus, Indiana


336 
WWUS53 KPAH 291217
SVSPAH

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
617 AM CST WED FEB 29 2012


INC147-173-291230-
/O.CON.KPAH.TO.W.0019.000000T0000Z-120229T1230Z/
SPENCER IN-WARRICK IN-
617 AM CST WED FEB 29 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR EAST CENTRAL WARRICK AND
NORTHERN SPENCER COUNTIES IN SOUTHWEST INDIANA UNTIL 630 AM CST...

AT 616 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
CONFIRMED TORNADO.  THIS DANGEROUS STORM WAS LOCATED 8 MILES
SOUTHEAST OF FOLSOMVILLE...OR 10 MILES NORTH OF ROCKPORT...MOVING
EAST AT 65 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3799 8683 3797 8687 3792 8712 3810 8718
      3821 8689 3821 8680 3800 8678
TIME...MOT...LOC 1217Z 252DEG 57KT 3803 8708

$$

Tuesday, February 28, 2012

Severe Thunderstorm Watch: Effective NOW until 12:00 AM CST


The Weather Centre
Mobile Storm Track Team (MSTT)
6:55 PM CST- February 28, 2012

A Severe Thunderstorm Watch has been issued by The Weather Centre for Central and Eastern Kansas effective now until midnight CST.

Discussion...
Radar has blossomed recently with very strong storms, including one with very strong rotation and additional tornado warning. This sudden burst of storms has led me to issue a short-term Severe Thunderstorm Watch. This watch is an upper level one, meaning an isolated tornado is possible. Our MSTT people have detected that these storms are only beginning to bloom. This will be worth watching before the real event starts up a bit farther south.

-Andrew

Tornado Warning- Hutchinson, Kansas




379 
WFUS53 KICT 290030
TORICT
KSC155-290100-
/O.NEW.KICT.TO.W.0001.120229T0030Z-120229T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WICHITA KS
630 PM CST TUE FEB 28 2012

THE NATIONAL WEATHER SERVICE IN WICHITA HAS ISSUED A

* TORNADO WARNING FOR...
  EASTERN RENO COUNTY IN SOUTH CENTRAL KANSAS...

* UNTIL 700 PM CST

* AT 626 PM CST...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED NEAR ARLINGTON...OR 15 MILES NORTH OF
  KINGMAN...AND MOVING NORTHEAST AT 60 MPH.

* LOCATIONS IMPACTED INCLUDE...
  HUTCHINSON...PARTRIDGE...SOUTH HUTCHINSON...BUHLER...YODER...
  WILLOWBROOK AND HUTCHINSON AIRPORT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING THAT
WAS IN EFFECT FOR THE SAME AREA.

&&

LAT...LON 3817 9795 3817 9770 3813 9770 3796 9771
      3776 9813 3790 9828
TIME...MOT...LOC 0030Z 229DEG 53KT 3790 9811
HAIL 1.75IN

$$

Tornado Watch: 5:00 PM CST - 5:00 AM CST 2/28 to 2/29

This was issued by The Weather Centre and not affiliated with the government.
The Weather Centre
Tornado Watch
4:10 PM CST - February 28, 2012

The Weather Centre has issued a tornado watch for east Oklahoma, west Arkansas and extreme southwest Missouri.

Discussion-
I have decided to go ahead and issue a tornado watch due to forecast high EHI levels and concerning hodographs shown on forecast soundings from the latest 18z NAM.
It looks like storms will start out in central Oklahoma and move eastward and intensify. As the storms move into the area now under a watch, I anticipate atmospheric spinning to take effect as the high EHI levels are present in the area. Instability is not particularly high, and for that reason I have not issued a Dangerous Tornado Watch. This would be a different story if we were in spring.
I did extend the tornado watch into extreme southwest Missouri, as any storms that fire ahead of the cold front may also hit Missouri. With the high EHI values, I feel that this move was necessary.

With this watch I am expecting...
•An isolated tornado (weak-moderate)
•Large Hail
•Damaging Winds Likely

Shearing will make for also another aid for possible rotation in the atmosphere, but the lack of any major instability I feel that this won't be a terribly huge player in how the tornado situation plays out.

-Andrew

Afternoon Prognosis

TERMS TO KNOW:
Hodograph: A device measuring distance from its starting point as the device ascends through the atmosphere on a weather balloon. Circular shapes can indicate rotation in the atmosphere.
EHI: A combination of spinning and helicity to make for, in my eyes, the best attempt to forecast where apt tornado conditions may be.
CAPE: Instability. Values above 1000 j/kg can be conductive for thunderstorms.

Prognosis--
SPC has lowered tornado threat and eliminated the 10% tornado risk. At the same time, the 5% tornado risk area has expanded north.
The main issue is that this tornado threat, in my eyes, may still be needed.

Latest 18z NAM is indicating high values of EHI (spinning+instability equation that can help determine a tornadic atmosphere) present on the Oklahoma Arkansas border. At that same time, storms should be just beginning to enter that area, with the 18z NAM projecting these storms to be fairly weak. However, this weakness is likely understated- At the point in time in question, the squall line will be not be a line yet, but it will be a weakly put together line of separate storm cells. Judging by forecast high EHI values and CAPE above 1000 j/kg, this should be an interesting night.

Here's a comparison for forecast hodographs of the 18z NAM (left) and the 12z GFS (right). While the models are on different runs, I have affixed them to be at the same forecast time.
The 18z NAM is honestly pretty concerning, with two roughly circular shapes present in the forecast. To start off with the whole hodograph is concerning, as the hodograph shows a half circle shape before suddenly turning into two tight bands of circles.  The sudden changeover to the circles makes me think that there may be too strong winds in the atmosphere to create a robust tornado, but that is dashed after the hodograph reveals the circular formations, both of which are likely indicative of a rotational motion in the atmosphere.
The 12z GFS is much more modest, having the hodograph take a similar half-circle-sudden-change path, but where the NAM shows the circles, the GFS shows it's attempt to make a circle, but believes that winds will be too tight for rotation to be shown. After that, the GFS hodograph shows it going off the screen but likely making a near full circle shape. Again, that is one of the more concerning features of this hodograph.

Midday Prognosis

12z NAM Is printing a scary scenario this evening with dangerously high Helicity (1st image) and EHI (2nd image). Again, EHI is the spinning in the atmosphere plus energy in the atmosphere. Values over 1 are dangerous.

Since this is done from my phone, the Helicity image is the one with pink in the image.

Update this afternoon.
Andrew

Severe Weather Prognosis (2/28/12)


As expected, the Storm Prediction Center did not issue a moderate risk for today, which in my eyes was a good move.
That does not, however, mean that the risk today will be zero. In reality, it is actually pretty substantial.
The first image is the overall outlook for severe storms in general. The second image indicates the chance for a tornado. I have come to learn that when there is a 10% chance of a tornado, a tornado can be reported in that 10% area. This time, however, that 10% area is so small that the chance of a tornado inside that 10% area seems lower than what it seems.

Prognosis-
A severe weather event is possible today in Arkansas, Missouri and west Tennessee, among other states. Forecast models indicate shearing levels between the surface and 700mb to be pretty sufficient on the GFS, with speeds of above 50 knots. However, this big shearing is in Missouri, with slightly lower speeds in Arkansas, thereby slightly reducing the tornado threat. Good shearing is also present in the surface-500mb area, but again, the big wind speeds are to the north and west of the main tornado risk put out by the SPC.

Precipitation should start this afternoon and congeal into something better than disorganized cells later in the afternoon/evening. An atmospheric cap will be over the area where storms break out, but it will be a very weak one, so these storms should easily break it.

An atmospheric cap is what's called CINH in the meteorology world. CINH is detected when a layer of warm air is present over the cooler atmospheric air up in the skies (warm air in the storms rises through the cool air over the atmosphere to make storm clouds and then storms.). If this CINH is too strong, the storms will be forced to stop at the 'cap' of warm air, as the air is too warm so the storms cannot continue rising through the atmosphere. This thereby 'caps' the storm and keeps it from getting stronger.

The tornado threat in Arkansas will be an overnight one, with maximum EHI (instability and spinning motion combined) values coming into the state at 3:00 AM CST. This is a very dangerous situation, as many will be asleep and not be able to hear a tornado coming. Additionally, tornadoes are much harder to be seen at night.

I will provide another update this afternoon. Stay safe everyone.
-Andrew

Monday, February 27, 2012

Prognosis on Feb. 28-29 Severe Weather Event

Prognosis--

Latest short range models I am seeing are developing a fair squall line starting tomorrow around 5:00 PM CST, with the squall one forming later in the evening. The line looks to be separate storm cells congealed into a weak line formation. This would be okay for supercell formation, but radar returns really are not impressive. Some strong storms certainly look possible from this, but a devastating event is not in the books here.
Just glancing at radar returns from the latest short range models tells me that the least held together storm cells look to be present in east Oklahoma into Kansas and Missouri. After that, the tornado threat looks to weaken in Arkansas as the storms turn more linear and less of individual cells.

Opinion on SPC Day 2 outlook...
The SPC appears to be accurately portraying this threat, but I am not thinking that a 'moderate risk' level is necessary for tomorrow. The way the NAM is playing out things tells me that Arkansas will probably not get anything in a moderate risk atmosphere, but if the SPC does decide it is necessary, I think it would be a low level moderate risk.
However, the NAM is having surface winds at over 20 MPH across the entire potentially affected area, leading the way for possible wind shearing which would easily make the way for the threat of tornadoes.

Summer Forecast 2012 for India to be issued on 18th Feb 2012

METD WEATHER
AKSHAY DEORAS
SEVERE WEATHER FORECASTER

The countdown for the official summer forecast of METD WEATHER has begun.The forecast will be issued on Sunday,18th March 2012 late afternoon hours (IST).
The forecast will be issued for the entire nation including Nagpur for the month
March end-April-May. The driving force behind the forecast will be state of oscillation at the eq.central pacific (ENSO) which is fading away now from the La Nina which played a major role in 2010,2011 weather across the Nation. The current parameters are indicating that the neutral conditions shall appear from this spring.However unless verified it will be too early to speak about it.

The weather forecast will be issued on this blog,facebook page of METD Weather and scribd page.
As METD WEATHER has entered the print media recently in Nagpur,the weather forecast ( Along with occasional) updates will be issued in Tarun Bharat newspaper (Marathi language),Lokmat ( Marathi Language) and in The Hitavada ( English) after some days ( 2 or 3)
After a big gap,the weather forecasts also will begin again for the exciting Tornado Alley from March itself.The season has already began and is progressing smoothly so far.

Further, a classic setup is coming together in the Southern plains from Tuesday into Wednesday.Due to time limitations,I cant write much but stay tuned with

spc.noaa.gov to monitor the conditions...

Solar Activity, Sunspots and UK Summer Weather Forecast 2012

Solar Activity, Sunspots and UK Summer Weather Forecast 2012

As you may or may not be aware via my work and forecasts since 2009, I firmly believe that the UK has now entered a long term pattern of cooler wetter summers and more severe winters. Please feel free to examine any of my early blog or video entries. This does not necessarily mean that every summer or winter will follow this exact trend, and as a large part of this winter has also quite conclusively proven. However, it does mean that the vast majority of the summer and winters are likely to be this way. The main aim of Exacta Weather has always been to make as many people as possible aware of this transition in weather and climate over the coming years and decades.
 
This period of transition is largely due to major changes in solar activity levels and how this affects major natural factors here on earth. This transitional period is also part of a cyclical and predictable pattern that has occurred many times throughout our earth's history.
 
So let's take sunspots and their importance, for example. Sunspots are dark magnetic regions that are visible on the surface of the solar disc.
 
The amount of solar energy we receive from these sunspots, and the earth directed ejections have an important bearing on a number of major natural factors including: 1. The heating of the stratosphere 2. Atmospheric circulation 3. Ocean circulation 4. Cloud formation
 
Sunspots are also a good indicator of how magnetically active the sun is. The more magnetically active the sun is, the larger and more intense the sunspots are. Solar storms are also generally emitted from areas that surround these sunspots. However, a less magnetically active sun sets off a whole chain reaction of changes to a number of attributes that influence our climate and weather patterns. The sunspots and solar storms become less intense and infrequent when the sun is not as magnetically active. This also allows the cosmic ray flux to increase and hit earth more frequently. The increase in cosmic rays enhances low level cloud coverage and deflects heat back into space, something that occurred during the Maunder Minimum.
 
UV rays are also an equally important attribute when the sun is less magnetically active. Less UV rays are emitted from solar storms when there are less sunspots. A decrease in UV radiation and solar winds hitting the earth's upper atmosphere alter the properties of the stratosphere, atmospheric circulation and the distribution of storm tracks. The amount of solar radiation that we receive also has an important bearing on the heating of ocean currents such as the Gulf Stream, which is especially significant to the likes of the UK and Ireland. I have also extensively reported on all of these factors quite frequently over the past few years.

1 
2 
3

FIG.1 - Near solar maximum in 2001 (NASA/SOHO)

FIG.2 - Galileo sunspots 1612 (Science Museum)

FIG.3 - 27th February 2012 (NASA/SOHO)
 
The point I am trying to illustrate here, is that we are now recording extra solar activity today that we weren't recording several years ago or through the lenses of Galileo's telescope (FIG 1 & 2). Just look at the magnitude of the sunspots from Galileo (FIG.2) 33 years before the Maunder Minimum in comparison to today's sun in (FIG.3). Galileo was simply recording these with his telescope at certain times of the day. Today, we are constantly recording solar storms and sunspots in 3D 'close up and from the side' since the NASA twin satellite launch in 2006. We are now also meant to be heading into a solar maximum and seeing some huge increases in solar activity according to many other sources.
 
However, I have reported many times that solar activity and sunspots are minuscule in comparison to what they should be right now, and in accordance to all NASA's predictions to date in recent years. I have also strongly emphasised that the low levels of solar activity that we have experienced in recent years, will also enhance periods of low solar activity in the present and future solar cycles. We are now facing such an extremely low period of solar activity over the coming years and decades, due to the strong correlation of historical evidence that I have analysed repeatedly. Furthermore, in some of my earlier posts that date back over the past three years, I have also reported and stressed my concerns that we are heading for a new Dalton/Maunder minimum like scenario. Some recent solar activity indices and the behaviour of the thermosphere could also be a strong indication that this is occurring much sooner than others sources are currently anticipating.
 
This will also not be counteracted by any so called effects of global warming or CO2 based on my own calculations, and the historical evidence that I have reviewed to date. In periods of high solar activity, up to double the amount of UV rays are emitted from stronger solar storms, which contribute towards the formation of ozone. This effectively traps heat radiation and acts as an insulator (warming) during periods of high solar activity.
 
Summer 2012 outlook

So in terms of this summer and based on the parameters that I consider, we are likely to see a continuation of this cooler and wetter trend for the summer as a whole. It would initially appear that another relatively grey and cool summer is on the cards for many. This does not mean that there will be no warm spells whatsoever throughout this summer. However, any warmer spells are likely to offer more in the way of some quite muggy and humid weather at times. I will also report on any viable warm periods of weather for up to two months in advance in my future forecast updates.
 
I also don't want to go as far as saying that the summer will be as cold as last year, but I also don't want to rule out a similar scenario unfolding either. If we were to experience another summer of similar magnitude to the latter, then some serious scientific acknowledgement will be required as to where our future climate is actually heading, especially over the coming years. The Milankovitch cycle strongly vindicates that ice will return to parts of the northern hemisphere, once the summers become cool enough. The Milankovitch cycle also predicted this pattern with astounding accuracy in the past, and it also places us at this point in the Milankovitch cycle today.
 
Conclusion

At the very best we are looking at an unsettled to mixed summer for this year. The summer is likely to be hampered by periods of relatively cool and very wet weather at times. As a whole the temperatures for summer are likely to be near or below average, dependent on which scenario unfolds out of the given two. Rainfall amounts are also likely to be near or above average for the summer as a whole. In terms of the 2012 Olympics and although it does become extremely difficult to forecast for a two-week period this far out in advance, they are also likely to be pretty mixed in terms of the primary location in London. However, as we progress through August and into September, there is the potential for some warm or very warm periods of weather at times.
 
A number of other weather events that have already occurred in other parts of the world this year, also appear to tie in quite well with a number of recent and historical weather observations that I have personally compiled. They also suggest another cool and possibly flood riddled summer. Now although I would prefer to report on the possibility of such events occurring nearer the time, my forecasting parameters suggest that the most prone time frame for any such flash flooding occurrences this summer are between the latter part of July and through to September.
 
No Meteorological or climate models have been used in the production of this long range forecast, or any of my long range forecasts that date back over the past three years. They are all made on a number of personal observations that also include: solar activity and historical weather patterns from my own unique collective data. This is why I am able to issue a forecast this far in advance without being limited by what the models are indicating. These are the same methods that have served me pretty well to date and will continue to do so in the future over computer models. This method of forecasting allows me to make a long term judgement on the factors that I consider to be the most important, and what I also consider to be the most reliable in the future for long term weather forecasting.
 
Disclaimer – If any aspect of my original long range forecast requires amendment, I will make an appropriate revision of this for up to two months in advance when possible. This is effectively still a long range forecast in itself, if you compare this to that of others. Please allow some slight deviations in exact timing of given scenarios, I.e. some months may slightly overlap or periods of certain weather types may be more prolonged/shorter than originally forecast, due to the nature of long range weather forecasting and how far ahead this forecast is being issued.
 
THE WINTER REVIEW WILL BE POSTED ON THE ACCURACY PAGE SHORTLY AFTER 1ST MARCH 2012.
 
James Madden (UK Long Range Forecaster)
 
Published: Monday 27thFebruary 2012 Content copyright © 2010-2012. Exacta Weather. All rights reserved.

UK Spring Weather Forecast 2012

Spring Weather Forecast 2012

Now although the spring and autumn periods have become an extremely difficult period to forecast for in recent years, due to some of the unusual patterns that have developed. March and into mid April are looking to offer some relatively dry weather at times in terms of rainfall amounts at present. This is likely to create the usual drought fears as we head into the summer as some reservoirs are already operating at low levels after the below average rainfall from this winter.

The March to April period is also initially looking like a mixed bag of cold and milder weather at times. It will also be particularly windy at times with some wintry showers in places within this period too. However, the latter part of April and into May could offer some potentially warmer and sunnier periods of weather at times. There does remain some uncertainty with myself in regard to the actual rainfall amounts that we are likely to experience in the second half of spring at present. On this basis, I will say that the rainfall amounts are likely to be near or below average for the spring period as a whole. Temperatures are also likely to be near or below average as a whole for spring dependent upon the May period too.

Disclaimer – If any aspect of my original long range forecast requires amendment, I will make an appropriate revision of this for up to two months in advance when possible. This is effectively still a long range forecast in itself, if you compare this to that of others. Please allow some slight deviations in exact timing of given scenarios, I.e. some months may slightly overlap or periods of certain weather types may be more prolonged/shorter than originally forecast, due to the nature of long range weather forecasting and how far ahead this forecast is being issued.
 
James Madden (UK Long Range Forecaster)
 
Published: Monday 27thFebruary 2012
Content copyright © 2010-2012. Exacta Weather. All rights reserved.

Sunday, February 26, 2012

February 28-29 Storm Discussion (2/26/12)

Prognosis-


Storm Prediction Center has issued a Slight Risk for severe weather on 'Day 3' (2 days away, because Day 1 is today, day 2 is tomorrow, etc.). This Slight Risk includes a 30% risk of severe weather in Arkansas, Southwest Missouri and East Oklahoma, with formidable risks still present in Northeast Texas and the rest of the aforementioned states.

A worry I have to start with is the tilt of the storm. Every storm has a tilt. There is a positive tilt, in which 500mb winds (seen above) will be strongest to the southwest of the system, or a negative tilt, where the strongest winds will be to the southeast of the system. This situation involves a negative tilt storm, and let me tell you why that is bad news.

Negative tilted troughs indicates that the storm has reached maturity and is at maximum strength. Additionally, negative tilted troughs will have cold air running over the warm air, which thus provides additional instability and makes for more severe thunderstorms.

These 500mb winds are also concerning, as the top wind speeds appear to be up to 110 knots, which equates to about 130 MPH. This raises the concern for wind shearing. With high winds at different height levels in the atmosphere, wind shearing can take place. This shearing makes the environment for tornadoes much more conductive than without shearing. Unfortunately, that appears to be what will be happening in this situation.

This is what's called a hodograph. Hodographs measure where the radiosonde is being taken by winds in the atmosphere, which are then used to tell if there is rotation in the atmosphere. A radiosonde is what is sent up in those big weather balloons by the National Weather Service. This hodograph is forecast for the time storms are to be present in Arkansas. This hodograph was based near Hughes, Arkansas.

In this hodograph, we see forecast strong lower level winds as the lines are very long from one number to the next. Notice how it begins to form a half circle shape, meaning that there is some form of rotation being detected at that point in Arkansas. Suddenly, the half circle stops and makes a full circle/square shape. This is exactly what no one wants to see.

What this complete shape means is that there is suddenly a very tight area of rotation in the atmosphere that could cause a tornado. No meteorologist ever wants to see that complete shape.

Moving on, the line then goes off the chart, but likely makes another half circle shape, again indicating some form of rotation may be present.

This hodograph tells us that there may be some tornadic activity in the area come February 28-29. I am concerned about that complete circle that was shown in the hodograph, and I believe that will be something to seriously watch.

The NAM is showing that there will be a lifting mechanism in place to get the storms going. This image portrays the Lifted Index, or LI. When the LI goes negative, it means that stronger storms are likely. When it is positive, it means that the atmosphere is more stable than not.

The Lifted Index here calculates to about -5 in Arkansas and Texas, which is some pretty good instability that could very well get those storms rocking.

The final index is the Energy Helicity Index (EHI). It calculates rotation + energy (CAPE) in the atmosphere to make one of the better indicators for potential tornadoes. Values over 1 are considered apt for tornadoes.

In this image, we see values of 1 to 1.25 in some scattered spots in Arkansas, leading me to believe that Arkansas will be where the strongest of storms happen and where the best chance for a tornado will be. I find it hard to believe that people in the Lower Great Lakes will get anything big out of this as there will be more limited moisture and atmospheric instability.

All in all, I suggest you keep a sharp eye on this. It could get interesting.

-Andrew

Saturday, February 25, 2012

Brief Look into Winter 2012-2013


Here are forecasted precipitation and temperature anomalies (respectfully) for DJF (December, January, February). These forecasts are from the Ensemble Canonical Correlation Analysis (ECCA) forecast system at the Climate Prediction Center.

For precipitation, the ECCA is projecting above normal precipitation across the northern US, but also majorly in the West US, where a 40% chance is present. For the North US, it looks like widespread areas of up to 10% are present. The same is present in the Northeast.

As for temperatures, it appears a major area of below normal temperatures are forecasted in the Plains, Midwest, Ohio Valley, South Plains, Southeast, Northwest, Southwest. The High Plains and Northeast are slightly above normal, though.

This is simply a look into next winter and not a forecast.

February 28-29 Storm Discussion

"Dynamic System Signals Spring's Commencement"

A dynamic system is poised to strike the US and bring everything from snow to possible tornadoes. Here's the latest:

Snowfall
The strong system that comes through will be cold on the north part, indicating that the event will be quite a snowy one. Accumulations at this point look to be pretty substantial, with this strong a system not keeping 12 inches+ out of the question. Then again, it is a bit too far out to forecast snowfall. Any snowfall should be wind driven, with this strong a system making for possible blizzard conditions in the Dakotas into Minnesota.

Severe Weather
There does look to be some severe weather possible with this system. Lower, middle, and upper level winds look to be pretty strong during this event, with 700mb winds possible reaching above 70 knots (80 MPH). A strong jet stream (over 130 knots (150 MPH) are possible) combined with a strong lower level jet stream (70 knots + possible) makes for a very potent tornado set-up in the spring and summer. However, it is late February. Thus comes the issue of lack of instability. Without instability and lifting mechanisms, it looks like this event will cause some possible brief spin-ups in north parts of the rain area, with some more potent rotation in the severe weather area.

Questions can be asked below.
-Andrew

Potential Severe Weather Event Feb. 28 (Issued 2/25/12)

Top left image: 700mb winds
Top right image: 300mb winds
Bottom left image: 850mb winds
Bottom right image: Precipitation
The set-up for severe weather continues to intensify with major wind speeds at heights that are monitored for tornado development. If winds at any of the 3 wind images are high, it usually indicates a risk for some spinning motion in the air which could then cause tornadoes.
What the GFS is currently showing is a few clusters of storms that would then evolve into a squall line. Squall lines are traditionally unfavorable for tornadoes as they are cells in a linear formation, like trying to have car wheels turning inside a box. It just doesn't work.

It looks like this level of wind shear would be favorable for some tornadic activity, but it is impossible to predict where tornadoes will occur. These are just guesses.

There is the issue on how there is virtually no CAPE, or instability, forecast for the storms to use. Additionally, the Lifted Index (lift) and CINH (Cap that stops instability) are next to nothing, if nothing. The non-presence of those indices pretty much cancels any potential of severe weather. However, the way that this is mapped out tells me that a brief, weak tornado is possible. Thunderstorms will be likely as this is a squall line when you come down to it.

Friday, February 24, 2012

Potential Severe Weather Event on February 28, 2012 (2/24/12)

I am closely watching the potential for some rare severe weather in the Midwest this upcoming Tuesday. Here's hour 114 of the 12z GFS.


Top left image: The top left image is 700mb wind speeds. The 700mb level is generally considered the area where 'jet streaks' (areas of strong winds within a jet stream) are found. Anyway, we see wind speeds of over to 70 knots, which equates to 80 MPH. 80 MPH is fairly strong for the 700mb level and can very well be conductive for severe weather. Seeing as this wind is flowing northeast, storms that form will be influenced and be moving northeast as well.

Top right image: The top right image is 300mb winds, which are the jet stream winds. In order for severe storms to form, there is usually a strong jet stream In this case, we have a jet stream of up to 130 knots present across a big swath of the Midwest, which equates to 150 MPH. 150 MPH is very strong and is nothing to mess with. To give you an idea of how strong it is, the jet stream present for the devastating April 27, 2011 tornado super outbreak was around 150 MPH.

Bottom left image: The bottom left image is 850mb winds. 850mb winds can detect how fast air flows, as the 850mb level is commonly watched for air temperatures at the surface. 850mb winds in this image show that wind speeds will be up to 70 knots+, which as shown above is over 80 MPH. Strong 850mb winds are usually pretty good for tornadic activity, so this will be something to watch.

Bottom right image: This is precipitation. In a couple images before this, the storms appear to form as a squall line turning into a cluster of storm cells. Multicelled storm clusters are typically the most dangerous and can be more conductive for tornadoes than squall lines. This will be something to closely watch.

We did pull up the best possible analogue picked out by the CIPS Analogue system, and here's what it has for severe weather reports from February 24, 2001.
As you can see, it was a pretty active day for severe weather, with 11 tornado reports, 99 wind reports and 59 hail reports. I can see this happening if it was moved north into the Midwest and Lower Great Lakes.

This could be a pretty serious event and will have to be watched.
Any questions can be asked below.
-Andrew

Long Range Forecast Update (2/24/12)

Prognosis- Just took a look at the 12z GFS. It's looking like the infamous Alaskan Vortex will be returning in a week or so. Until then, expect progressive storm systems and ridges until about a week, when a more solid pattern of a ridge should set up. Thus, some quieter weather is probably in the books in the future.
Personally, this looks to be it for winter. I am seeing some dynamic storm systems that may give the North Plains a good surprise for snow, but other than that, I can't say things are looking too positive.

Any questions can be asked below.
-Andrew

February 22-24 Snowfall Event Wrap-Up

Starting February 22, a strong 'Saskatchewan Screamer' system dropped from Canada and into the US. A Saskatchewan Screamer (SS) system is a storm system that forms in Saskatchewan, Canada, and quickly moves, or 'screams', through the US.

February 22, 2012 Surface Analysis at 03z
This is the surface analysis for 3z February 22, which is 9:00 PM CST February 21. We see the two parts of the storm- the Saskatchewan Screamer just northwest of North Dakota, and the storm system on the Oklahoma/Texas border. At this point, the storm is not of particular interest and not of particular strength.

February 22, 2012 Surface Analysis at 06z.

This is the surface analysis for midnight Feb. 22, CST. The Saskatchewan Screamer (which will now be referred to as System 1) is now racing into South Dakota with a central pressure of 998 millibars. At this point, it is of interest as the system is being strengthened by a jet stream that has winds at roughly 125 MPH. The jet stream of the 0z and 12z timeframes just before and after (respectively) of this surface analysis indicates that a strong trough had developed in the jet stream that had pushed it south. This trough in the jet stream tells me that its southward motion would continue, but the strength of the jet stream to the west would keep the southward movement also at an eastern movement, making for a southeast direction.

February 22, 2012 Surface Analysis at 12z
At 12z (6 AM CST), System 1 has now progressed into Iowa, keeping the main snows behind into the Dakotas. Central pressure indicates the system is at 999 millibars. Of more interest is System 2, now in Oklahoma. The central pressure is at 1005 millibars- not too strong. However, there is now a dry line in place that increases concern for severe thunderstorms. The presence of a warm front over what used to be a stationary front indicates that the warm air mass is now on the move and will now begin to displace other air masses, therefore instigating more thunderstorms along the front. Now, this would be a bigger concern if temperature differences were larger. Temperature readings (red numbers) north and south of the warm front are not too different from each other, thereby significantly lowering the severe weather threat.

After that, everything gets complicated as surface analysis maps do not clearly depict the system differences. However, it does come to point that the main snows begin to come back south towards the Lower Great Lakes.

February 23, 2012 Surface Analysis at 12z
A day later, the main system appears as a 989 millibar system. To watch now is the frontal system stretched from Kansas to West Virginia. Eventually, this cold front will turn into a warm front and move north as the 989mb system moves east into Missouri.

This warm front then becomes the focus for where snow will fall. Tight temperature gradients in the summer are typically the focus of thunderstorms. A temperature gradient is the difference of temperatures between points. This temperature gradient is also a good point for snowfall to occur in the winter. The gradient is also an area where snow banding sets up. This banding is typically where the heaviest of heavy snows fall.

In this situation, the temperature gradient (TG) appeared to set up in the northern half of Illinois. Yesterday afternoon, a line of precipitation moved north across northern Illinois. In areas of lighter precipitation, there was reported rain and a mix of precipitation. In the heaviest precipitation, very large snowflakes were reported to be falling. Accumulations of about an inch resulted.

In the aftermath of this band, it was mentioned by National Weather Service Chicago that this band of precipitation had indicated where the heaviest snow would fall overnight.
And that's where it became foggy.

The National Weather Service and RUC Short Range model were at odds. The RUC placed the heavier snows on the WI/IL border, while the NWS put Northeast Illinois in the heaviest snowfall. In the end, the RUC model won out.

Snowfall amounts were highest on the Wisconsin/Illinois border, where very isolated 8-10 inches were found. The National Weather Service became somewhat erratic in the first couple hours as the storm went on, with NWS Chicago suddenly lowering snowfall amounts and shifting the heaviest snowfall to right up against Lake Michigan.

The system then continued eastward with substantial strength. Again, the frontal positions were of issue, and snowfall amounts may have ended up slightly less than what is shown on here. The only reason that it is unsure is because the snow event is just ending.

If you have any reports, they would be appreciated below.
I am recovering from what may have turned out to be a brush with the flu and am feeling much better. Thanks to everyone who sent well wishes!

-Andrew

Thursday, February 23, 2012

Rain-to-Snow Changeover Earlier than Anticipated


Radar and observations are indicating that the changeover from rain to snow has happened. It was supposed to occur this evening, but now that it has changed over, I do anticipate snowfall accumulations to be higher than what is being shown on the models right now. In order for the models to recognize this unexpected changeover, I recommend not using the short range models until the 20z (2:00 PM CST) runs, which by then should have detected the early changeover.

Concerning Tornado Threat Present Today in North Kentucky

day1otlk_1300.gif
I am concerned about the tornado threat in North Kentucky today. The Storm Prediction Center has outlined Kentucky, Tennessee, north Georgia and north Alabama, South Ohio and South Indiana in a slight risk of severe thunderstorms.

WB013_JETSTREAM300_HOUR_K_6.png
The GFS's forecast of the jet stream shows the Southern Jet and main Mid Latitude jet stream trying to intersect in Oklahoma. Notice how both jet streams back away from each other in Kentucky. When jet streams are forced away from each other (they would have come together in Oklahoma and stayed together through the rest of the country), it indicates a massive rising of air. In other words, a lot of instability in the atmosphere. Diverging jet streams are usually seen in the Spring and Summer with more powerful storm systems.

day1probotlk_1300_torn.gif
The SPC outlines an alarming 10% risk of a tornado in north Kentucky. Now, the SPC outlines tornado risks at low levels because no one can predict a tornado. It is impossible. That said, I have come to learn that a 10% chance of a tornado outlined by the SPC usually results in a tornado in the outlined area.

A strong jet stream will not help matters. This strong jet stream will create a lot of turbulence in the region, meaning a more dynamic and unpredictable wind pattern that will likely become more conductive for rotation in the atmosphere.

NAM_218_2012022312_F06_36.0000N_87.0000W_HODO.png
Here is a hodograph. A hodograph is basically a tracer from the area it was released to the upper points of the atmosphere. A hodograph is attached to a radiosonde, which is the instrument sent up that is attached to those big weather balloons. Anyhow, when a hodograph comes back in a circular formation, it means that there is some form of rotation action occurring in the atmosphere. We can see a half circle shape in the lower parts of the atmosphere. (The height is characterized by the distance from the first point, which in this case appears to be the dot on the left half of the image.)