| 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 050600
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT MON APR 05 2010
VALID 051200Z - 061200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER/MIDDLE MO
RIVER VALLEY AND MIDWEST...
...SYNOPSIS...
LARGE SCALE PATTERN WILL UNDERGO SOME AMPLIFICATION TODAY...WITH A
STRONG BELT OF SOUTHWESTERLY FLOW ALOFT MAINTAINED FROM THE
SOUTHWEST STATES TO THE UPPER MIDWEST/GREAT LAKES REGION AHEAD OF AN
UPPER TROUGH ADVANCING FROM THE WESTERN STATES TO THE ROCKIES.
...LOWER-MIDDLE MO RIVER VALLEY/MIDWEST/OH VALLEY...
BENEATH A STRENGTHENING ELEVATED MIXED LAYER...BOUNDARY LAYER
MOISTURE /GENERALLY CHARACTERIZED BY LOWER 60S F SURFACE DEWPOINTS/
WILL STEADILY DEVELOP NORTHWARD TODAY ACROSS PORTIONS OF OK/KS AND
THE ADJACENT LOWER TO MIDDLE MO RIVER VALLEY IN CONCERT WITH A
NORTHWARD RETREATING WARM FRONT.
INITIALLY...AIDED BY A MODERATELY STRONG LOW LEVEL JET/ELEVATED
MOISTURE TRANSPORT REGIME...ELEVATED TSTMS SHOULD DEVELOP/EXPAND
NORTHEASTWARD THIS MORNING...MAINLY ACROSS PORTIONS OF NORTHERN
KS/EASTERN NEB INTO NORTHERN MO AND IA. MODERATE ELEVATED BUOYANCY
COUPLED WITH SUFFICIENT SHEAR THROUGH THE CLOUD BEARING LAYER COULD
SUPPORT A SEVERE HAIL RISK.
OTHERWISE...A STRENGTHENING EML ALOFT SHOULD GENERALLY CAP SURFACE
BASED TSTM DEVELOPMENT MUCH OF THE AFTERNOON ACROSS THE MAJORITY OF
THE MOISTENING/NORTHWARD RETREATING WARM SECTOR. BUT SOME
TEMPORAL/SPATIAL WINDOW FOR SURFACE BASED SUPERCELLS /INCLUDING A
TORNADO THREAT/ IS POSSIBLE MAINLY DURING THE LATE AFTERNOON/EARLY
EVENING ALONG THE IMMEDIATE SURFACE FRONT. AFOREMENTIONED MODAL
UNCERTAINTY REGARDING PROSPECTS FOR SURFACE BASED INITIATION LATE
AFTERNOON/EARLY EVENING PRECLUDES SOMEWHAT HIGHER TORNADO
PROBABILITIES AT THIS TIME ACROSS NORTHERN MO/SOUTHERN IA AND
PERHAPS SOUTHEAST NEB/NORTHEAST KS.
OTHERWISE...ELEVATED SUPERCELLS CAPABLE OF MAINLY SEVERE HAIL SHOULD
BE THE DOMINANT SCENARIO WITH THE GREATEST TSTM COVERAGE ANTICIPATED
TONIGHT...VIA THE ARRIVAL OF LARGE SCALE HEIGHT FALLS/INCREASED
FORCING FOR ASCENT...AND AN ASSOCIATED STRENGTHENING LOW LEVEL
JET/ISENTROPIC LIFT REGIME ALONG/NORTH OF THE SURFACE FRONT. THIS
INCLUDES PORTIONS OF NORTHERN KS/SOUTHEAST NEB INTO MUCH OF
IA/NORTHERN IL AND ADJACENT AREAS...WITH AT LEAST AN ISOLATED SEVERE
THREAT CONTINUING WELL THROUGH THE NIGHT.
...MIDWEST/LOWER OH VALLEY THROUGH AFTERNOON...
SEVERE THREAT IS MUCH MORE UNCERTAIN TODAY WITH EASTWARD EXTENT
ACROSS THE LOWER OH VALLEY INCLUDING PORTIONS OF IL/INDIANA INTO
OH/KY. IN THE WAKE OF EARLY MORNING SHOWERS/TSTMS ACROSS THE LOWER
OH VALLEY VICINITY...WARM FRONT/ASSOCIATED MOIST BOUNDARY LAYER IS
EXPECTED TO STEADILY RETURN NORTHWARD ACROSS MO/IL/INDIANA DURING
THE DAY. WHILE FORCING ON THE LARGE SCALE WILL BE LIMITED...THE
POSSIBILITY OF A PASSING SPEED MAX AND A WEAKLY CAPPED BOUNDARY
LAYER COULD SUPPORT SOME SURFACE BASED TSTM DEVELOPMENT THIS
AFTERNOON. GIVEN VEERING/STRONG LOW TO MID TROPOSPHERIC FLOW...AT
LEAST A CONDITIONAL SEVERE THREAT WILL EXIST...INCLUDING THE
POSSIBILITY OF A SEVERE HAIL/TORNADO RISK. REGION WILL BE CLOSELY
MONITORED FOR AN EXPANSION OF THE EXISTING CATEGORICAL SLIGHT RISK.
...CENTRAL KS TO WESTERN OK LATE THIS AFTERNOON/EVENING...
DEEP CONVECTIVE COVERAGE SHOULD BE MORE SPARSE ALONG THE DRYLINE
FROM CENTRAL KS TO WESTERN OK...WITH ONLY CONDITIONAL/ISOLATED-TYPE
SEVERE PROBABILITIES WARRANTED AT THIS TIME. BUT IT SEEMS AS IF A
FEW TSTMS MAY FORM AIDED BY LATE AFTERNOON/EVENING ARRIVAL OF MODEST
LARGE SCALE FALLS IN CONJUNCTION WITH AN INCREASINGLY MOIST/WEAKLY
CAPPED BOUNDARY LAYER. MODERATE INSTABILITY COUPLED WITH
STRENGTHENING MID LEVEL SOUTHWESTERLY FLOW /50-65 KT/ COULD SUPPORT
SUPERCELLULAR DEVELOPMENT.
..GUYER/GRAMS.. 04/05/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z