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| Probabilistic Tornado Graphic | |||||||||
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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| Probabilistic Damaging Wind Graphic | |||||||||
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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| Probabilistic Large Hail Graphic | |||||||||
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 221252
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT FRI MAR 22 2013
VALID 221300Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON/EVENING
FROM E CENTRAL TX ACROSS NRN LA TO W CENTRAL MS...
...SYNOPSIS...
A PRONOUNCED MIDLEVEL SHORTWAVE TROUGH WILL DIG SEWD OVER THE GREAT
BASIN TOWARD THE FOUR CORNERS BY EARLY SATURDAY...WHILE GRADUAL
HEIGHT RISES OCCUR DOWNSTREAM OVER THE SE STATES. LEE CYCLOGENESIS
WILL OCCUR ACROSS ERN NM/SE CO IN ADVANCE OF THE APPROACHING
MIDLEVEL TROUGH. FARTHER SE...A REMNANT LEE CYCLONE ACROSS N TX
THIS MORNING WILL MOVE GENERALLY EWD NEAR I-20 WHILE WEAKENING AS
THE WARM SECTOR SPREADS NWD TO NRN LA...IN CONJUNCTION WITH SUBTLE
SPEED MAXIMA EJECTING EWD OVER THE SRN PLAINS. THE ASSOCIATED
SURFACE FRONT WILL LIKEWISE SAG SWD ACROSS CENTRAL/E TX IN THE WAKE
OF THE WEAK SURFACE LOW. THE WEAK LOW/SURFACE FRONT WILL PROVIDE
THE PRIMARY FOCUS FOR ISOLATED SEVERE STORM DEVELOPMENT THIS
AFTERNOON/EVENING FROM E TX INTO NRN LA AND POSSIBLY W CENTRAL MS.
...E TX...NRN LA...W CENTRAL MS THIS AFTERNOON/EVENING...
BOUNDARY LAYER DEWPOINTS IN THE MID 60S ARE SPREADING NWD INTO SE
TX...WITH UPPER 60S ACROSS THE LOWER TX COAST. MEANWHILE...STEEP
MIDLEVEL LAPSE RATES CONTINUE TO OVERSPREAD TX FROM THE W. THE
INCREASING LOW-LEVEL MOISTURE...MIDLEVEL LAPSE RATES OF 7.5-8
C/KM...AND DAYTIME HEATING WILL BOOST AFTERNOON MLCAPE VALUES TO THE
1500-2500 J/KG RANGE FROM E TX INTO NRN LA ALONG AND S OF THE FRONT.
DESPITE A LACK OF OBVIOUS LARGER-SCALE SUPPORT FOR
ASCENT...LOW-LEVEL CONVERGENCE AND WEAKENING CONVECTIVE INHIBITION
ALONG THE FRONT COULD SUPPORT ISOLATED THUNDERSTORM DEVELOPMENT THIS
AFTERNOON FROM E CENTRAL TX INTO NRN LA. IF STORMS
FORM...DEEP-LAYER VERTICAL SHEAR AND BUOYANCY WILL BE FAVORABLE FOR
SUPERCELLS WITH AN ATTENDANT RISK FOR LARGE HAIL/DAMAGING WINDS. A
TORNADO OR TWO WILL ALSO BE POSSIBLE WITH STORMS THAT MOVE ALONG THE
SURFACE FRONT IN LA...WHERE LOW-LEVEL SHEAR WILL BE STRONGEST.
...SRN MS/AL OVERNIGHT...
A WAA REGIME WILL BECOME ESTABLISHED OVERNIGHT ALONG AN ERN SEGMENT
OF THE LLJ. MODERATE ELEVATED INSTABILITY CAN BE EXPECTED OVER THIS
AREA WHERE THE ERN EDGE OF THE STEEPER LAPSE RATES COINCIDE WITH THE
RETURNING MOISTURE JUST ABOVE THE SURFACE. ISOLATED LARGE HAIL WILL
BE POSSIBLE WITH THE STRONGER STORMS...BUT THE COVERAGE OF SEVERE
STORMS SHOULD REMAIN ISOLATED AT BEST.
...NE NM/SE CO THIS AFTERNOON/EVENING...
THOUGH LOW-LEVEL MOISTURE AND BUOYANCY WILL BE QUITE LIMITED...BUT
ASCENT DOWNSTREAM FROM THE AMPLIFYING MIDLEVEL TROUGH...STEEP LAPSE
RATES AND DEEP INVERTED-V PROFILES COULD SUPPORT AN ISOLATED STRONG
WIND GUST THREAT WITH HIGH-BASED CONVECTION LATE THIS
AFTERNOON/EVENING.
...CENTRAL/N TX OVERNIGHT...
LOW-LEVEL MOISTURE WILL RETURN NWD OVERNIGHT AS LOW-LEVEL SSWLY FLOW
INCREASES DOWNSTREAM FROM THE AMPLIFYING MIDLEVEL TROUGH OVER THE
ROCKIES. PRESENT INDICATIONS ARE THAT THE CAP MAY BE SUFFICIENT TO
INHIBIT ELEVATED THUNDERSTORM DEVELOPMENT THROUGH THE END OF THE DAY
1 FORECAST PERIOD. AS SUCH...HAVE REMOVED THE THUNDERSTORM AND LOW
HAIL PROBABILITIES BECAUSE THE THREAT IS TOO CONDITIONAL.
..THOMPSON/MOSIER.. 03/22/2013
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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