Good day everyone!
This will be a BUSY week as far as severe weather is concerned…especially this upcoming weekend.
The Storm Prediction Center (SPC) Norma, OK. has issued a SLIGHT risk of Severe Thunderstorms over portions of the CENTRAL/SRN PLAINS…
Based on my analysis of forecast Severe Weather Indices from F5 DATA Severe Weather Software, output from the ECMWF, GFS, and NAM – WRF models, information supports the outlined areas in the SPC Outlook.
Regarding any tornado activity, values of the EHI (Energy Helicity Index) within the 5% prob area in the SPC map, indicate some tornadoes could attain EF2 – EF3 strength. Based on this, and various indices, I have outlined a primary tornado threat area. I cannot rule out a secondary area over Kansas based on the consistency of the forecast parameters observed. It appears the prime time for this activity will be late afternoon to early evening
Significant hail COULD reach a little further north in the hail risk area, possibly to the OK border.
The following are some of the forecast severe weather indices from this morning:
SWEAT: 400 – 500
SBCAPE: 1500 – 2000 j/kg
MLCAPE: 750 – 1500 j/kg
LIFTED INDEX: -6 to -8
TOTALS TOTALS INDEX: 52 – 60
EHI: 2 to 5
CRAVEN BROOKS SEVERE: 10,000 – 40,000
You may compare indices with the following charts:
Residents within the slight risk area should monitor NOAA Weather Radio, and local NWS Office Statements and Warnings for severe weather that may occur in your area. ALL of the graphics to follow are linked..just click on them for the latest information regarding today’s severe weather.
INTELLICAST NWS DOPPLER RADAR
The SPC has issued a SLIGHT risk for Severe Thunderstorms for THE LOWER MS VALLEY in the Day 2 Convective Outlook
The Storm Prediction Center is still forecasting a SIGNIFICANT MUTLI – DAY SEVERE WEATHER EVENT for SAT / SUN /MON.
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0351 AM CDT WED APR 23 2014
VALID 261200Z – 011200Z
..SIGNIFICANT MULTI-DAY SEVERE EVENT EXPECTED ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS SATURDAY AND SUNDAY AND ACROSS THE MS VALLEY AND MID SOUTH ON MONDAY…STRONG TORNADOES ARE POSSIBLE…
MEDIUM RANGE FORECAST CONTINUES TO BE HEAVILY WEIGHTED TOWARD THE ECMWF DUE TO RUN-TO-RUN CONSISTENCY REGARDING THE 500MB EVOLUTION OF WRN U.S. TROUGH. CONCERNS REGARDING POLAR FRONT UNDERCUTTING STRONG SWLY FLOW ALOFT HAVE ABATED THIS MORNING. LATEST GUIDANCE DEEPENS LEE CYCLONE OVER SERN CO SATURDAY AFTERNOON WITH SUBSEQUENT MOVEMENT INTO WRN KS ON SUNDAY. INTENSE 500MB SPEED MAX APPROACHING 90KT SHOULD ROUND THE BASE OF THE TROUGH ALONG THE AZ/MEXICAN BORDER THEN EJECT INTO SWRN KS EARLY SUNDAY. AS A RESULT SFC LOW IS NOT EXPECTED TO ADVANCE APPRECIABLY EWD UNTIL LATER MONDAY AS SECONDARY MID-LEVEL SPEED MAX DEVELOPS FROM NORTH TX INTO THE LOWER OH RIVER VALLEY.
MODERATE TO EXTREME INSTABILITY SHOULD DEVELOP EAST OF THE DRYLINE SATURDAY AFTERNOON ALONG ERN PLUME OF STEEP LAPSE RATES. STRONGLY DIFLUENT FLOW ALOFT SHOULD ENCOURAGE VIGOROUS SUPERCELL DEVELOPMENT FROM PORTIONS OF WCNTRL TX…NWD INTO KS. VERY LARGE HAIL AND TORNADOES CAN BE EXPECTED WITH THIS ACTIVITY.
IT/S NOT ENTIRELY CLEAR HOW FAR EAST THE DRYLINE WILL MIX SUNDAY AS LOWEST PRESSURES WILL REMAIN FOCUSED ACROSS THE HIGH PLAINS OF WRN KS. MODELS MIX DRYLINE EAST OF I-35 CORRIDOR ACROSS OK BY 18Z SUNDAY BUT THE DAY5 FORECAST WILL ACCOUNT FOR DRYLINE NOT MIXING ACROSS THE PLAINS AS FAST AS MODELS CURRENTLY DEPICT. AS A RESULT…SUBSTANTIAL MID-LEVEL FLOW SHOULD OVERSPREAD THE MOIST/BUOYANT WARM SECTOR AND ANOTHER DIURNALLY-INITIATED ROUND OF POTENTIALLY TORNADIC SUPERCELLS COULD EVOLVE.
LATER MONDAY IT APPEARS THE SFC FRONT/DRYLINE SHOULD ADVANCE INTO THE MS VALLEY. SCATTERED-NUMEROUS SUPERCELLS SHOULD EVOLVE AHEAD OF THE FRONT FROM LA…NWD INTO MO AND POSSIBLY AS FAR EAST AS MIDDLE TN. TORNADOES AND LARGE HAIL REMAIN POSSIBLE WITH WARM-SECTOR CONVECTION.
Based on model consistency, and analysis of forecast Severe Weather Indices and parameters, Day 4 (Sat.) appears at the moment to hold the promise of the most significant severe weather. Based on continued analysis of forecast severe weather indices, I would not be surprised to see the SPC issue a MODERATE RISK area on Saturday, with a possible chance of a smaller HIGH RISK outline.
The forecast indicates that significant supercells could occur. These supercells will have the capability to produce large damaging hail, strong straight line winds, and a high probability of STRONG tornadoes (EF3 – EF5), which some could be long tracked.
Based on the information contained in the outlook, and the current forecast severe weather indices and parameters, this event has the potential to become a PDS (Particularly Dangerous Situation) over portions of the outlook area.
The following indices were chosen to give you an idea of what may be in store, and may be compared to the indices charts to which the links were posted previously in this synopsis.
SBCAPE: 2000 – 4000 j/kg
MLCAPE: 1000 – 2500 j/kg
LIFTED INDEX: -6 to -10
TOTALS TOTALS INDEX: 56 – 60
SWEAT: 400 – 500
As of the morning analysis of severe weather forecast data from F5 DATA Software, my current projection of where the best probability of severe activity and tornadic activity may occur are outlined in the following maps. A word of caution however… this will most likely have changes by Saturday as fluctuations occur in thermodynamics:
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS
OFFICIAL SKYWARN SPOTTER (ADVANCED)