Another Colonel Klink Moment! Friday Severe Storms, Potential Derecho! Real Time Severe Warnings Page


I told you so

I told you so

Fri 8AM to Sat 8 AM

Fri 8AM to Sat 8 AM

Tornado Probability

Tornado Probability

To Find Real Time Severe Warnings in Your Area, CLICK HERE

If you checked the last post, then you are aware that late Thursday night I told you that the SPC would probably alter their thinking regarding the severe risk area and include us in the region.   By Friday afternoon, there was a severe thunderstorm watch for the area and a tornado watch to our southwest.  What the deal is that we have a wave running along a warm front that is in our region.  Ahead of the main vort max (the wave) we have light to moderate rain in the afternoon with some lighting.  As the wave gets closer. the t’storm activity will become more pronounced.  It is not unusual to get severe weather on warm fronts, including tornadic activity.  In this case, with most likely elevated storms as I bet the wave is running on the 850 mb front, I would think that there is a fair chance for hail.  Also, winds aloft could get dragged down and bring hail in larger storms.  Remember, the core of the wave will be cold air aloft so between the temperature lapse rate from bottom to top and the warm front itself, there will be plenty of lift.  Its not out of the question that we may even have a derecho, which is a long line of strong straight line winds that tend to last for a pretty long time.  These winds, while straight line in nature, could get caught up in a rather chaotic winds that spin up a small tornado.  With the cold air aloft, I would also expect a lot of lightning.

Friday Severe Hail Probability

Friday Severe Hail Probability

The vertical profile indecies from 12Z Friday are pretty indicative and are probably what finally convinced the SPC to expand their risk area.  Both the GFS and the RUC have a SWEAT Index of around 450 in the afternoon and evening.  Even the NAM is running close to 400.  400 is generally the threshold of when one can expect to see the threat of tornadic activity increase.  Generally, if we get beyond 500, it’s almost a given that we will get something somewhere in the way of winds or tornadoes.  The winds at about 2000 feet were progged at about 75 knots.  Those winds could easily be dragged down to the ground and, with a derecho event, would certainly to just that.  A derecho event would be a dangerous high wind event that would cover at least a county wide area if not larger.  In that sense, they can be more destructive than a tornado that would affect a relatively small area.  Winds in a twister may be higher, but the coverage affected is smaller.  In this case, we have the jet stream to the north of the wave, which is helping to vent the system, really not too differently than a hurricane in some regards.  What this means is that this guy won’t go away with the cool of evening.  It’s a dynamically driven system.  So, expect this guy to roll across the state.  By the time it gets to the Appalacians late Friday night, then it may get separated from its support and start to wind down.

One thing that the models will be wrong about is the rain.  The RUC has the most and it only advertises a little more than 3/4 of an inch of rain by Friday night.  With all of the moisture getting dragged up over the warm front, methinks it may be more like double that amount if not more in some areas.

All in all, not a nice afternoon….a few hours ahead of schedule but again…it still qualifies as a Colonel Klink Moment.

DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1212 PM CDT FRI MAY 08 2009
  
   VALID 081630Z – 091200Z
  
   …THERE IS A MDT RISK OF SVR TSTMS PORTIONS OF WRN KY AND NRN TN…
  
   …THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS EWD THROUGH
   THE TN/LOWER OH VALLEYS EWD TO THE CAROLINAS…
  
   …THERE IS A SLGT RISK OF SVR TSTMS IN THE IA AREA…
   
 

Friday Severe Wind Probability

Friday Severe Wind Probability

  …TN/LOWER OH VALLEY…
   LONG LIVED BOW ECHO…MOVING EWD AT 60 KT…WAS APPROACHING THE MS
   RIVER AND IS EXPECTED TO TRACK MOSTLY EWD THROUGH THE REGION THIS
   AFTERNOON. THOUGH MESOSCALE MODELS SUGGEST WEAKENING WITH
   TIME…GIVEN THE WELL ORGANIZED SYSTEM MOVING INTO AN ENVIRONMENT
   WITH STRONG INSTABILITY…MLCAPES 2000-2500 J/KG…AND EFFECTIVE
   SHEAR NEAR 40 KT IS EXPECTED TO SUSTAIN WIDESPREAD WIND
   DAMAGE..SOMETIMES EXTREME. WIND AND HAIL IS FORECAST WITH THE SYSTEM
   UNTIL IT REACHES THE APPALACHIANS THIS EVENING. LOW LEVEL SHEAR WILL
   ALSO BE SUPPORTIVE OF TORNADOES…ESPECIALLY WITH THE ROTATING BOW
   HEADS.
  
   …NRN TX/SERN OK/AR/NRN LA…
   COLD FRONT AT MID MORNING EXTENDED FROM SERN KS SWWD INTO WRN TX
   NEAR LBB. FRONT IS EXPECTED TO MOVE SEWD TO NEAR A SGF-ADM-MAF LINE
   BY 23Z. MORNING SOUNDINGS SHOWED STRONG CAPPING BETWEEN 850-700
   MB…AND THIS SHOULD LIMIT CONVECTION ALONG THE FRONT THROUGH MOST
   OF THE DAY. DESPITE NO REAL DISCERNABLE SHORTWAVE TROUGH…MODELS
   DEPICT A SPEED MAX MOVING INTO THE REGION LATE THIS AFTERNOON WITH
   INCREASING DIFFLUENCE ALOFT. THIS WOULD RESULT IN STRENGTHENING LOW
   LEVEL CONVERGENCE ALONG THE FRONT… ESPECIALLY IN AND WEST OF THE
   ARKLATEX. ALL OPERATIONAL/MESOSCALE MODELS SHOW CONVECTION DEVELOPS
   ALONG THE FRONT IN ERN OK/NRN TX AFTER 22Z. STORMS THAT DEVELOP ARE
   LIKELY TO QUICKLY BECOME SEVERE GIVEN MLCAPES FROM 3000 TO 4000 J/KG
   AND MID LEVEL LAPSE RATES NEAR 9 C/KM INDICATE VERY LARGE HAIL WOULD
   BE THE MAIN THREAT.
  
   …CAROLINAS…..
   REMNANT MCS FROM WRN NC INTO NERN GA IS EXPECTED TO CONTINUE EWD
   INTO A MOIST AND DESTABILIZING AIR MASS…2000 J/KG MLCAPE WITH
   TEMPERATURES IN THE 80S. ALTHOUGH ACTIVITY WILL GRADUALLY DEVELOP
   SOUTH OF THE STRONGER WINDS ALOFT…UNIDIRECTIONAL WLY WINDS AT 20
   TO 30 KT THROUGH THE LOWER 6 KM MAY SUPPORT A LINEAR SYSTEM THIS
   AFTERNOON…WITH WIND DAMAGE THE PRIMARY THREAT.
  
   …IA/NWRN IL AND SWRN WI…
   A STRONG SHORTWAVE TROUGH OVER CENTRAL NEB/SD WILL TRACK EWD TO NEAR
   THE NEB/IA BORDER BY 00Z. COLD TEMPERATURES ALOFT…500 MB
   TEMPERATURES FROM -18 TO -22C…MODERATELY STEEP LAPSE RATES…40-50
   KT DEEP LAYER SHEAR AND LIFT ASSOCIATED WITH TROUGH/ASSOCIATED JET
   MAX SHOULD RESULT IN SUPERCELLS. HAIL AND WIND DAMAGE WILL BE THE
   MAIN THREATS.
  
   ..IMY/GRAMS.. 05/08/2009

DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1212 PM CDT FRI MAY 08 2009
  
   VALID 081630Z – 091200Z
  
   …THERE IS A MDT RISK OF SVR TSTMS PORTIONS OF WRN KY AND NRN TN…
  
   …THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS EWD THROUGH
   THE TN/LOWER OH VALLEYS EWD TO THE CAROLINAS…
  
   …THERE IS A SLGT RISK OF SVR TSTMS IN THE IA AREA…
  
   …TN/LOWER OH VALLEY…
   LONG LIVED BOW ECHO…MOVING EWD AT 60 KT…WAS APPROACHING THE MS
   RIVER AND IS EXPECTED TO TRACK MOSTLY EWD THROUGH THE REGION THIS
   AFTERNOON. THOUGH MESOSCALE MODELS SUGGEST WEAKENING WITH
   TIME…GIVEN THE WELL ORGANIZED SYSTEM MOVING INTO AN ENVIRONMENT
   WITH STRONG INSTABILITY…MLCAPES 2000-2500 J/KG…AND EFFECTIVE
   SHEAR NEAR 40 KT IS EXPECTED TO SUSTAIN WIDESPREAD WIND
   DAMAGE..SOMETIMES EXTREME. WIND AND HAIL IS FORECAST WITH THE SYSTEM
   UNTIL IT REACHES THE APPALACHIANS THIS EVENING. LOW LEVEL SHEAR WILL
   ALSO BE SUPPORTIVE OF TORNADOES…ESPECIALLY WITH THE ROTATING BOW
   HEADS.
  
   …NRN TX/SERN OK/AR/NRN LA…
   COLD FRONT AT MID MORNING EXTENDED FROM SERN KS SWWD INTO WRN TX
   NEAR LBB. FRONT IS EXPECTED TO MOVE SEWD TO NEAR A SGF-ADM-MAF LINE
   BY 23Z. MORNING SOUNDINGS SHOWED STRONG CAPPING BETWEEN 850-700
   MB…AND THIS SHOULD LIMIT CONVECTION ALONG THE FRONT THROUGH MOST
   OF THE DAY. DESPITE NO REAL DISCERNABLE SHORTWAVE TROUGH…MODELS
   DEPICT A SPEED MAX MOVING INTO THE REGION LATE THIS AFTERNOON WITH
   INCREASING DIFFLUENCE ALOFT. THIS WOULD RESULT IN STRENGTHENING LOW
   LEVEL CONVERGENCE ALONG THE FRONT… ESPECIALLY IN AND WEST OF THE
   ARKLATEX. ALL OPERATIONAL/MESOSCALE MODELS SHOW CONVECTION DEVELOPS
   ALONG THE FRONT IN ERN OK/NRN TX AFTER 22Z. STORMS THAT DEVELOP ARE
   LIKELY TO QUICKLY BECOME SEVERE GIVEN MLCAPES FROM 3000 TO 4000 J/KG
   AND MID LEVEL LAPSE RATES NEAR 9 C/KM INDICATE VERY LARGE HAIL WOULD
   BE THE MAIN THREAT.
  
   …CAROLINAS…..
   REMNANT MCS FROM WRN NC INTO NERN GA IS EXPECTED TO CONTINUE EWD
   INTO A MOIST AND DESTABILIZING AIR MASS…2000 J/KG MLCAPE WITH
   TEMPERATURES IN THE 80S. ALTHOUGH ACTIVITY WILL GRADUALLY DEVELOP
   SOUTH OF THE STRONGER WINDS ALOFT…UNIDIRECTIONAL WLY WINDS AT 20
   TO 30 KT THROUGH THE LOWER 6 KM MAY SUPPORT A LINEAR SYSTEM THIS
   AFTERNOON…WITH WIND DAMAGE THE PRIMARY THREAT.
  
   …IA/NWRN IL AND SWRN WI…
   A STRONG SHORTWAVE TROUGH OVER CENTRAL NEB/SD WILL TRACK EWD TO NEAR
   THE NEB/IA BORDER BY 00Z. COLD TEMPERATURES ALOFT…500 MB
   TEMPERATURES FROM -18 TO -22C…MODERATELY STEEP LAPSE RATES…40-50
   KT DEEP LAYER SHEAR AND LIFT ASSOCIATED WITH TROUGH/ASSOCIATED JET
   MAX SHOULD RESULT IN SUPERCELLS. HAIL AND WIND DAMAGE WILL BE THE
   MAIN THREATS.
  
   ..IMY/GRAMS.. 05/08/2009

DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1212 PM CDT FRI MAY 08 2009
  
   VALID 081630Z – 091200Z
  
   …THERE IS A MDT RISK OF SVR TSTMS PORTIONS OF WRN KY AND NRN TN…
  
   …THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS EWD THROUGH
   THE TN/LOWER OH VALLEYS EWD TO THE CAROLINAS…
  
   …THERE IS A SLGT RISK OF SVR TSTMS IN THE IA AREA…
  
   …TN/LOWER OH VALLEY…
   LONG LIVED BOW ECHO…MOVING EWD AT 60 KT…WAS APPROACHING THE MS
   RIVER AND IS EXPECTED TO TRACK MOSTLY EWD THROUGH THE REGION THIS
   AFTERNOON. THOUGH MESOSCALE MODELS SUGGEST WEAKENING WITH
   TIME…GIVEN THE WELL ORGANIZED SYSTEM MOVING INTO AN ENVIRONMENT
   WITH STRONG INSTABILITY…MLCAPES 2000-2500 J/KG…AND EFFECTIVE
   SHEAR NEAR 40 KT IS EXPECTED TO SUSTAIN WIDESPREAD WIND
   DAMAGE..SOMETIMES EXTREME. WIND AND HAIL IS FORECAST WITH THE SYSTEM
   UNTIL IT REACHES THE APPALACHIANS THIS EVENING. LOW LEVEL SHEAR WILL
   ALSO BE SUPPORTIVE OF TORNADOES…ESPECIALLY WITH THE ROTATING BOW
   HEADS.
  
   …NRN TX/SERN OK/AR/NRN LA…
   COLD FRONT AT MID MORNING EXTENDED FROM SERN KS SWWD INTO WRN TX
   NEAR LBB. FRONT IS EXPECTED TO MOVE SEWD TO NEAR A SGF-ADM-MAF LINE
   BY 23Z. MORNING SOUNDINGS SHOWED STRONG CAPPING BETWEEN 850-700
   MB…AND THIS SHOULD LIMIT CONVECTION ALONG THE FRONT THROUGH MOST
   OF THE DAY. DESPITE NO REAL DISCERNABLE SHORTWAVE TROUGH…MODELS
   DEPICT A SPEED MAX MOVING INTO THE REGION LATE THIS AFTERNOON WITH
   INCREASING DIFFLUENCE ALOFT. THIS WOULD RESULT IN STRENGTHENING LOW
   LEVEL CONVERGENCE ALONG THE FRONT… ESPECIALLY IN AND WEST OF THE
   ARKLATEX. ALL OPERATIONAL/MESOSCALE MODELS SHOW CONVECTION DEVELOPS
   ALONG THE FRONT IN ERN OK/NRN TX AFTER 22Z. STORMS THAT DEVELOP ARE
   LIKELY TO QUICKLY BECOME SEVERE GIVEN MLCAPES FROM 3000 TO 4000 J/KG
   AND MID LEVEL LAPSE RATES NEAR 9 C/KM INDICATE VERY LARGE HAIL WOULD
   BE THE MAIN THREAT.
  
   …CAROLINAS…..
   REMNANT MCS FROM WRN NC INTO NERN GA IS EXPECTED TO CONTINUE EWD
   INTO A MOIST AND DESTABILIZING AIR MASS…2000 J/KG MLCAPE WITH
   TEMPERATURES IN THE 80S. ALTHOUGH ACTIVITY WILL GRADUALLY DEVELOP
   SOUTH OF THE STRONGER WINDS ALOFT…UNIDIRECTIONAL WLY WINDS AT 20
   TO 30 KT THROUGH THE LOWER 6 KM MAY SUPPORT A LINEAR SYSTEM THIS
   AFTERNOON…WITH WIND DAMAGE THE PRIMARY THREAT.
  
   …IA/NWRN IL AND SWRN WI…
   A STRONG SHORTWAVE TROUGH OVER CENTRAL NEB/SD WILL TRACK EWD TO NEAR
   THE NEB/IA BORDER BY 00Z. COLD TEMPERATURES ALOFT…500 MB
   TEMPERATURES FROM -18 TO -22C…MODERATELY STEEP LAPSE RATES…40-50
   KT DEEP LAYER SHEAR AND LIFT ASSOCIATED WITH TROUGH/ASSOCIATED JET
   MAX SHOULD RESULT IN SUPERCELLS. HAIL AND WIND DAMAGE WILL BE THE
   MAIN THREATS.
  
   ..IMY/GRAMS.. 05/08/2009

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