DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 200554
SWODY1
SPC AC 200552

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1252 AM CDT MON AUG 20 2012

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER NERN NM INTO THE WRN TX
PANHANDLE...

...SYNOPSIS...
A FULL LATITUDE UPPER TROUGH WILL REMAIN OVER THE ERN HALF OF THE
CONUS WITH AXIS FROM THE UPPER GREAT LAKES SWD INTO THE CNTRL GULF
COAST. AT THE SURFACE...HIGH PRESSURE WILL EXTEND ACROSS MUCH OF THE
MS VALLEY INTO THE TN VALLEY...WITH A WEAK LOW PRESSURE TROUGH FROM
THE WRN ATLANTIC SWWD TO SRN PARTS OF THE GULF COAST STATES. AMPLE
MOISTURE NEAR THIS BOUNDARY AS WELL AS COOL AIR ALOFT WITH THE
TROUGH WILL FAVOR SCATTERED TO NUMEROUS STORMS DURING THE DAY.

AN UPPER RIDGE WILL REMAIN OVER WRN STATES WITH NWLY FLOW ALOFT
ACROSS THE PLAINS. WITH A WEAK LEE TROUGH DEVELOPING BY
AFTERNOON..SHEAR PROFILES WILL BECOME FAVORABLE FOR A FEW SUPERCELLS
WITH HAIL ACROSS THE SRN HIGH PLAINS.

OTHER STORMS WILL OCCUR ACROSS THE UPPER OH VALLEY AREA WITH STRONG
DAYTIME HEATING BENEATH COOL PROFILES ALOFT.

...NERN NM INTO THE WRN OK/TX PANHANDLES...
WEAK SLY SFC FLOW WILL VEER TO NWLY ALOFT CREATING MODERATELY LONG
STRAIGHT HODOGRAPHS FAVORABLE FOR A FEW SLOW MOVING HAIL STORMS.
WITH MARGINAL BOUNDARY LAYER MOISTURE...MAX SIZES SHOULD BE AROUND
1.00 TO 1.50 INCH DIAMETER. CELLS WILL LIKELY INITIATE ACROSS THE
HIGHER TERRAIN OVER NERN NM...AND WILL MOVE AND PROPAGATE SEWD INTO
TX BY 00Z WHERE LOCALIZED SEVERE WINDS MAY ALSO OCCUR.

...ERN FL PENINSULA...
A SWLY FLOW REGIME WILL FAVOR CONVECTIVE DEVELOPMENT ACROSS ERN FL
DURING THE AFTERNOON. TALL CAPE PROFILES WILL BE PRESENT WITH
DEWPOINTS WELL INTO THE 70S F AND DAYTIME HEATING. PULSE HAIL AND
WIND WILL BE POSSIBLE.

...SERN LA INTO THE ERN CAROLINAS...
MODEST SWLY MIDLEVEL FLOW WILL REMAIN OVER THE REGION BENEATH THE
BASE OF THE UPPER TROUGH. LOW LEVEL MOISTURE WILL REMAIN ALONG A
DIFFUSE BOUNDARY WHICH WILL SUPPORT INSTABILITY BUT LAPSE RATES
ALOFT WILL BE RATHER POOR SUGGESTING WEAK CONVECTION. A MARGINAL
SEVERE THREAT WILL EXIST ONCE HEATING OCCURS AND LOW LEVEL LAPSE
RATES STEEPEN...BUT WILL LIKELY CEASE QUICKLY AFTER SUNSET. A FEW
SEMI-ORGANIZED CELLS OR LINES MAY MATERIALIZE.

...ERN OH INTO WRN PA...
THERE WILL BE LITTLE FOCUS/FORCING FOR STORMS...BUT HEATING WILL
STEEPEN LAPSE RATES WITH NO CIN AND AMPLE CAPE FOR LOW TOPPED STORMS
FROM OH INTO PA. ALSO SUPPORTING UPDRAFTS WILL BE RELATIVELY MOIST
RH PROFILES ALOFT. THUS...ISOLATED STRONG TO SEVERE STORMS CAPABLE
OF MARGINAL HAIL ARE EXPECTED DURING THE HEAT OF THE DAY AND ENDING
SHORTLY AFTER SUNSET.

..JEWELL/COHEN.. 08/20/2012

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