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May 5, 2007 1300 UTC Day 1 Convective Outlook |
Updated: Sat May 5 12:48:13 UTC 2007 |
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 central plains 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 051243
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CDT SAT MAY 05 2007
VALID 051300Z - 061200Z
...THERE IS A HIGH RISK OF SVR TSTMS TODAY THROUGH THIS EVENING
ACROSS PARTS OF CENTRAL KS AND CENTRAL NEB...
...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF SOUTHERN
SD...WESTERN AND CENTRAL NEB...CENTRAL KS...AND NORTHWEST OK...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE PLAINS
STATES FROM ND TO TX...
...REGIONAL OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES IS
FORECAST THIS AFTERNOON ACROSS PARTS OF CENTRAL KS AND CENTRAL
NEB...
...CENTRAL PLAINS...
MORNING WATER VAPOR IMAGERY SHOWS LARGE UPPER TROUGH OVER THE
NORTHERN ROCKIES. THIS FEATURE IS EXPECTED TO REMAIN NEARLY
STATIONARY THROUGH TODAY...AS 80-90 KNOT MID LEVEL SPEED MAX ROTATES
INTO THE CENTRAL PLAINS. SURFACE LOW NOW OVER SOUTHEAST CO WILL
LIFT SLOWLY NORTHWARD INTO WESTERN NEB BY THIS AFTERNOON...WITH
DRYLINE EXTENDING SOUTHWARD ACROSS CENTRAL KS AND INTO EXTREME
WESTERN OK. POCKETS OF LOW CLOUDS AND POSSIBLY SHOWERS WILL PERSIST
THROUGH THE MORNING ALONG AND EAST OF THE DRYLINE...SOMEWHAT
LIMITING DAYTIME HEATING. HOWEVER...12Z DDC SOUNDING SHOWS THAT
ENVIRONMENT IS EXTREMELY MOIST AND UNSTABLE...AND ONLY WEAKLY
CAPPED. COMBINATION OF WEAK HEATING AND LARGE SCALE ASCENT SHOULD
REMOVE CAP AND ALLOW SCATTERED THUNDERSTORM DEVELOPMENT RELATIVELY
EARLY TODAY.
...CENTRAL NEB/KS...
PRESENT INDICATIONS ARE THAT CONVECTION WILL INTENSIFY BY EARLY
AFTERNOON ALONG DRYLINE FROM WESTERN NEB INTO CENTRAL KS. ACTIVITY
MAY BE ISOLATED...BUT POTENTIAL EXISTS FOR REPEAT INITIATION AS
STORMS MOVE QUICKLY NORTH-NORTHEASTWARD OFF THE DRYLINE. FORECAST
SOUNDINGS THROUGHOUT THIS REGION SHOW VERTICAL SHEAR PROFILES VERY
FAVORABLE FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL. COMBINATION OF
EXTREME INSTABILITY /MLCAPE VALUES OF 2500-4000 J/KG/...LOW LCL
HEIGHTS...HIGH SURFACE DEWPOINTS...AND STRONG LOW LEVEL SHEAR
/EFFECTIVE HELICITY VALUES OF 200-300 M2/S2/ ALSO FAVOR THE
POTENTIAL FOR LONG-LIVED...STRONG TORNADOES. ACTIVITY IS EXPECTED
TO LIFT NORTH-NORTHEASTWARD ACROSS MUCH OF NEB/KS OVERNIGHT WITH A
CONTINUED RISK OF TORNADOES...LARGE HAIL...AND DAMAGING WINDS.
...OK/TX...
LARGE SCALE FORCING FOR VERTICAL MOTION WILL INCREASE ALONG SURFACE
DRYLINE AFTER DARK FROM WESTERN OK INTO WEST TX. SCATTERED
THUNDERSTORMS ARE LIKELY TO DEVELOP ALONG THIS AXIS...WHERE HIGH
CAPE VALUES AND SUFFICIENT VERTICAL SHEAR WILL PROMOTE A RISK OF
SEVERE/SUPERCELL STORMS. LARGE HAIL WILL BE THE MAIN
THREAT...ISOLATED TORNADOES COULD ALSO OCCUR OVER WESTERN
OK/NORTHWEST TX THIS EVENING.
...NEB/SD...
FARTHER NORTH...SIGNIFICANT UPPER FORCING WILL OVERSPREAD NORTHERN
NEB AND SOUTHERN SD LATE THIS AFTERNOON AND EVENING. WARM SECTOR
AIR MASS MAY NOT DEVELOP THIS FAR NORTHWARD. HOWEVER...FORECAST
SOUNDINGS INDICATE SUBSTANTIAL ELEVATED CAPE AND STRONG SHEAR
PROFILES. ORGANIZED MULTICELL OR SUPERCELL STORMS CAPABLE OF LARGE
HAIL WILL BE LIKELY OVER THIS REGION.
..HART/GRAMS.. 05/05/2007
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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