DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 151209
SWODY1
SPC AC 151207

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0707 AM CDT MON APR 15 2013

VALID 151300Z - 161200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF EASTERN
OK...NORTHERN AR...AND SOUTHERN MO...

...OK/AR/MO...
MORNING WATER VAPOR LOOPS SHOW AN UPPER LOW CENTERED OVER THE
DAKOTAS/MN...WITH BROAD CYCLONIC FLOW ACROSS MOST OF THE WESTERN
2/3RDS OF THE NATION. AT THE SURFACE...A FRONT EXTENDS FROM WEST TX
NORTHEASTWARD ACROSS SOUTHEAST OK INTO CENTRAL MO. THIS BOUNDARY IS
FORECAST TO RETREAT NORTHWESTWARD TODAY BEFORE SAGGING SOUTHWARD
AGAIN THIS EVENING...AND WILL BE THE PRIMARY FOCUS FOR STRONG/SEVERE
THUNDERSTORMS LATER TODAY.

PRESENT INDICATIONS ARE THAT A MODERATELY MOIST AND UNSTABLE AIR
MASS WILL BECOME ESTABLISHED ALONG/SOUTH OF THE FRONT ACROSS PARTS
OF EASTERN OK/NORTHERN AR/SOUTHERN MO. SATELLITE IMAGERY AND MODEL
GUIDANCE SUGGEST THAT LARGE SCALE FORCING FOR ASCENT WILL BE
ILL-DEFINED THIS AFTERNOON OVER THE CENTRAL U.S. NEVERTHELESS...A
COMBINATION OF STRONG DAYTIME HEATING AND SUSTAINED LOW LEVEL WARM
ADVECTION ACROSS THE REGION IS EXPECTED TO SUBSTANTIALLY WEAKEN THE
CAPPING INVERSION BY 16/00Z. AT LEAST ISOLATED INTENSE STORMS
SHOULD DEVELOP OVER THE SLIGHT RISK AREA...PERSISTING THROUGH THE
EVENING HOURS. DESPITE RATHER LIMITED AREAL COVERAGE OF
STORMS...FORECAST SOUNDINGS THIS EVENING SUGGEST THE POTENTIAL FOR
SUPERCELLS CAPABLE OF LARGE HAIL...DAMAGING WINDS...AND A FEW
TORNADOES /MLCAPE OF 1500-2000 J/KG AND 3KM SRH OF 200-300 M2/S2/.
ACTIVITY MAY SPREAD INTO SOUTHERN IL BY LATE EVENING BEFORE
WEAKENING OVERNIGHT. A MORE FOCUSED SOURCE OF LIFT IS THE PRIMARY
LIMITING FACTOR PRECLUDING A MORE WIDESPREAD AND SUBSTANTIAL SEVERE
WEATHER EVENT.

...FL...
A WEAK SHORTWAVE TROUGH IS PROGRESSING EASTWARD ACROSS THE EASTERN
GULF OF MEXICO TOWARD FL THIS MORNING. MEANWHILE...A MOIST/UNSTABLE
AIR MASS REMAINS OVER THE SOUTHERN FL PENINSULA. IT APPEARS LIKELY
THAT SCATTERED AFTERNOON THUNDERSTORMS WILL FORM OVER THIS REGION AS
THE TROUGH APPROACHES DURING PEAK HEATING. COOL MID LEVEL
TEMPERATURES AND RATHER STEEP MID LEVEL LAPSE RATES WILL PROMOTE
STRONG UPDRAFTS CAPABLE OF HAIL AND GUSTY WINDS. WEAK LOW/MID LEVEL
WIND FIELDS SHOULD LIMIT CONVECTIVE ORGANIZATION.

..HART/GARNER.. 04/15/2013

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