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Feb 5, 2008 1630 UTC Day 1 Convective Outlook |
Updated: Tue Feb 5 16:44:10 UTC 2008 |
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006). |
Public Severe Weather Outlook |
The SPC is forecasting ...severe thunderstorms expected over parts of the parts of the mid south this afternoon and tonight....
Please read the latest public
statement about this event.
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Categorical Graphic |
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Probabilistic Tornado Graphic |
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Probabilistic Damaging Wind Graphic |
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Probabilistic Large Hail Graphic |
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SPC AC 051616
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1016 AM CST TUE FEB 05 2008
VALID 051630Z - 061200Z
...THERE IS A HIGH RISK OF SVR TSTMS LARGE PART OF AR...PARTS OF NRN
MS...WRN TN...WRN KY...AND A SMALL PART OF SRN IL AND SERN MO......
...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK BUT
EXTENDING ENEWD INTO THE OH RIVER VALLEY AND TOWARD THE TN RIVER
VALLEY......
...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE SRN PLAINS
ENEWD INTO THE OH/TN RIVER VALLEYS AND CENTRAL GULF STATES......
OVERALL SYNOPTIC SETUP WILL BECOME QUITE FAVORABLE FOR AN OUTBREAK
OF SEVERE THUNDERSTORMS AND TORNADOES...INCLUDING LONG-LIVED
TORNADIC SUPERCELLS...CENTERED ON THE MID SOUTH THIS AFTERNOON AND
EVENING. MAXIMUM SEVERE THREAT AREA WILL SHIFT EWD ACROSS MS RIVER
INTO WRN TN VALLEY AND NRN GULF STATES TONIGHT.
...SYNOPSIS...
DEEP UPPER LEVEL TROUGH AND ASSOCIATED EXTREME MID AND UPPER LEVEL
WIND FIELDS /H5 JET MAX IN EXCESS OF 90 KT...130+ KT AT H25/ WILL
SUSTAIN AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE SRN PLAINS
INTO THE GULF COAST STATES/OH RIVER VALLEYS THROUGH THE PERIOD.
WIDESPREAD...ELEVATED THUNDERSTORMS CONTINUE TO INCREASE THIS
MORNING ASSOCIATED WITH EJECTING LOWER AMPLITUDE WAVE FROM NRN TX
ACROSS OK. ADDITIONAL WIDESPREAD THUNDERSTORMS CONTINUE TO
BACKBUILD/PERSIST WITHIN BROAD REGION OF LOW LEVEL WAA AND ENHANCED
ASCENT NEAR SURFACE COLD FRONT PUSHING SLOWLY SWD OVER THE OH RIVER
VALLEY.
SURFACE LOW IS DEVELOPING RED RIVER AREA OF SRN OK/NRN TX AND IS
FORECAST TO DEEPEN FURTHER AS IT LIFTS NEWD ALONG SURFACE FRONT INTO
NRN AR BY LATE TODAY AND INTO SRN IND LATER TONIGHT. AS UPPER
SYSTEM EJECTS EWD...DRY LINE/N-S SURFACE TROUGH WILL BEGIN TO SURGE
EWD ACROSS CENTRAL/ERN TX AND SHIFT STEADILY EAST ACROSS THE
LOWER/MID MS RIVER VALLEYS TONIGHT. MEANWHILE...SURFACE FRONT
TRAILING FAST MOVING SHORTWAVE TROUGH NOW MOVING ACROSS THE UPPER
MIDWEST IS EXPECTED TO STALL AND THEN LIFT NWD SLIGHTLY LATE TONIGHT
AS A WARM FRONT IN RESPONSE TO DEEPENING SURFACE LOW ACROSS THE
LOWER OH RIVER VALLEY. NET RESULT WILL BE PERSISTENT MOISTENING
WITHIN BROAD WARM SECTOR FROM ERN TX INTO THE TN VALLEY THROUGH THE
PERIOD...WITH SURFACE DEW POINTS AOA 60F EXTENDING AS FAR NORTH AS
THE OH RIVER VALLEY.
...LOWER OH/MID MS RIVER VALLEY ENEWD INTO KY/MID OH RIVER VALLEY...
EARLY DAY ACTIVITY WILL CONTINUE TO POSE AN ISOLATED RISK OF SEVERE
WITHIN WEAK INSTABILITY AND SMALL CAP FROM PORTIONS OF SERN MO INTO
NRN KY/SWRN OH. SHEAR WILL REMAIN MORE THAN ADEQUATE FOR
SUPERCELLS...AND TORNADO THREAT MAY INCREASE THROUGH THE EARLY
AFTERNOON. AS SURFACE LOW DEEPENS AND MOVES ENEWD ACROSS SRN MO THIS
EVENING AND THE STRONG MID/UPPER JET MAX ROTATES NEWD ACROSS AR
FORECAST SOUNDINGS INDICATE EXTREME SHEAR AND EFFECTIVE INFLOW
TAPPING LOW/MID 60F SURFACE DEW POINTS.
WITH SURFACE BOUNDARIES EXPECTED TO REMAIN VICINITY OF SERN MO TO
SRN OH THERE WILL BE A STRONG FOCUS FOR SURFACE BASED SUPERCELLS TO
DEVELOP THRU THE EVENING. HAVE EXTENDED THE HIGH RISK NEWD INTO WRN
KY/SRN IL FOR THE CONCERN OF LONG LIVED TORNADIC SUPERCELLS VICINITY
BOUNDARY. IN ADDITION A STRONGLY FORCED SQUALL LINE IS EXPECTED TO
DEVELOP AHEAD OF THE DEEPENING SURFACE LOW WITH POTENTIAL FOR
SIGNIFICANT WIND DAMAGE THIS EVENING EWD INTO LOWER OH VALLEY.
...MID SOUTH INTO THE CENTRAL GULF COAST STATES...
EXPECT ISOLATED SEVERE THUNDERSTORMS...INITIALLY ELEVATED...WILL
PERSIST AS THEY SPREAD ENEWD AHEAD OF WEAKENING IMPULSES IN
SUBTROPICAL JET STREAM. ACTIVITY SHOULD BECOME INCREASINGLY
SURFACE-BASED BY EARLY THIS AFTERNOON WITHIN EXTREME SHEAR AND VERY
MOIST BOUNDARY LAYER INCREASING RISK OF ISOLATED TORNADOES/DAMAGING
WINDS. 12Z SOUNDING FROM LZK AND MODIFIED OUN SOUNDING INDICATE
MLCIN IS RELATIVELY WEAK ALREADY. ONCE CAPPING BREAKS FROM ERN OK
INTO NRN HALF OF AR/FAR SRN MO WITH THIS INITIAL WAVE...SEVERE
THREAT SHOULD RAMP UP QUICKLY.
APPEARS SRN/ERN AR INTO FAR NRN LA/WRN TN/NWRN MS WILL REMAIN
RELATIVELY FREE OF MOIST CONVECTION THROUGH THE EARLY AFTERNOON...AS
EARLY DAY ACTIVITY SHIFTS NEWD ACROSS THE OZARK PLATEAU/MO.
THUS...AS MAIN IMPULSE AND ASSOCIATED SURFACE FRONT SPREAD EWD LATE
TODAY...ROBUST THUNDERSTORM DEVELOPMENT SHOULD ENSUE WITHIN MLCAPE
AROUND 1000 J/KG AND WEAK CIN. EXTREME SHEAR WITH SFC-1 KM SRH IN
EXCESS OF 300 M2/S2 SUGGESTS STORMS WILL RAPIDLY DEVELOP ROTATION
AND AN ATTENDANT TORNADO THREAT ONCE THEY ROOT INTO DEEPLY MOIST
BOUNDARY LAYER. ANY TORNADIC SUPERCELLS COULD PRODUCE A LONG-LIVED
SIGNIFICANT TORNADO IN THIS ENVIRONMENT. STORMS MAY TEND TO EVOLVE
INTO A BROKEN SQUALL LINE LATE THIS EVENING AS FRONT INTERACTS WITH
RICH GULF MOISTURE AND MOVES ACROSS THE GULF COAST STATES OVERNIGHT.
DAMAGING WIND THREAT COULD ALSO BECOME WIDESPREAD GIVEN EXTREME
WIND FIELDS JUST OFF THE SURFACE...ALTHOUGH THREAT FOR A SIGNIFICANT
TORNADO WILL CONTINUE OVERNIGHT WITH LEWP AND PRE-SQUALL LINE
DEVELOPMENT.
..HALES.. 02/05/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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