SPC AC 311607
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1107 AM CDT SAT MAR 31 2007
VALID 311630Z - 011200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM EASTERN NEB/SRN MN/IA INTO
THE MID AND LOWER MS VALLEY......
...SYNOPSIS...
VIGOROUS S/WV TROUGH ERN KS/OK WITH ASSOCIATED 80-90KT MID LEVEL JET
MAX MOVING NEWD ACROSS LWR MO/MID MS VALLEY BY THIS EVENING.
DEEPENING SURFACE LOW SERN NE/KS BORDER TRACKS NNEWD THRU WRN IA
INTO SRN MN BY EARLY TONIGHT. COLD FRONT FROM SURFACE LOW EXTENDS
SWD THRU ERN KS/ERN OK INTO S TX. PREFRONTAL CONVECTION WELL IN
ADVANCE OF FRONT FROM ERN AR INTO SWRN LA.
...MID WEST STATES...
LOW LEVEL MOISTURE WITH DEWPOINTS INTO UPR 50S IS STREAMING NWD
AHEAD OF SURFACE LOW AND COLD FRONT INTO SRN IA. A WARM FRONT
CURRENTLY ACROSS NWRN IA TO NRN IL WILL LIFT NWD DURING AFTERNOON
POSSIBLY TO MN/WI BORDERS.
THERE IS AN INCREASED CONCERN FOR SUPERCELLS AND TORNADOES AHEAD OF
DEEPENING SURFACE EWD ACROSS IA NWD TO THE WARM FRONT. WITH
TEMPERATURES WARMING TO NEAR 70F MLCAPES SHOULD CLIMB TO AROUND 1000
J/KG PRIOR TO CONVECTIVE INITIATION. DEEP LAYER SHEAR INCREASES TO
60KT IN WARM SECTOR AS JET MAX PIVOTS NEWD ACROSS AREA ALONG WITH
VEERING LOW LEVEL WINDS...PARTICULARLY VICINITY WARM FRONT ACROSS
IA. SURFACE INITIATION LIKELY BY 18Z WITH SEVERE THUNDERSTORMS
DEVELOPING QUICKLY EARLY THIS AFTERNOON. SUPERCELLS ARE EXPECTED
INCLUDING BOTH TORNADO AND LARGE HAIL POTENTIAL.
STORMS WILL EVENTUALLY EVOLVE INTO MORE OF A SQUALL LINE MODE BY
LATE AFTERNOON AS THREAT SPREAD EWD INTO NRN IL AND SWRN WI AND
ACROSS SRN MN BORDER.
...MID MS VALLEY...
WHILE STRONG SHEAR WILL BE IN PLACE ACROSS THIS AREA AHEAD OF COLD
FRONT...DESTABILIZATION WILL BE SLOWER GIVEN CURRENT CLOUD
COVER...HOWEVER BY MID AFTERNOON MLCAPES OF 500-1000 J/KG COULD
DEVELOP IN AREAS OF SURFACE HEATING. THIS WILL BE SUFFICIENT FOR
STRONG/SEVERE THUNDERSTORMS TO FORM ALONG/AHEAD OF COLD FRONT. SHEAR
MORE THAN SUFFICIENT FOR ISOLATED SUPERCELLS WHICH SUPPORT A TORNADO
AND DAMAGING WIND THREAT.
...LOWER MS VALLEY...
ONGOING ORGANIZED CLUSTERS OF STRONG/SEVERE STORMS ACROSS AR INTO
SWRN LA SUPPORTED BY DEEPER MOISTURE AND MDT SHEAR. WHILE LESS
ORGANIZED THREAT EXISTS FOR SEVERE GIVEN THE UPPER SYSTEM PULLING
AWAY TO THE N/NE...AT LEAST A FEW SEVERE STORMS ARE LIKELY THRU THE
AFTERNOON WHICH WILL INCLUDES BOTH ISOLATED SUPERCELLS AND BOWING
STRUCTURES.
..HALES/GUYER.. 03/31/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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