SWODY1
SPC AC 160600
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT FRI MAY 16 2008
VALID 161200Z - 171200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ERN CAROLINAS INTO
SERN VA...
...SYNOPSIS...
HIGH AMPLITUDE UPPER RIDGE WILL BUILD OVER THE WRN U.S. COAST. UPPER
LOW WILL CUTOFF OVER NRN MEXICO WITH SPLIT FLOW BETWEEN CUTOFF UPPER
LOW AND NRN STREAM TROUGH. THE TWO STREAMS MERGE OVER THE ERN STATES
WHERE UPPER TROUGH WILL AMPLIFY SEWD THROUGH THE OH AND TN VALLEYS.
MID LEVEL JET WILL STRENGTHEN FROM TN VALLEY THROUGH MID ATLANTIC AS
THE UPPER TROUGH AMPLIFIES. SRN STREAM IMPULSE WILL EJECT NEWD INTO
THE GULF COASTAL REGION. AT THE SURFACE A WEAK LOW IS FORECAST OVER
THE MID ATLANTIC WITH A TRAILING COLD FRONT SWWD THROUGH WRN NC INTO
THE WRN GULF EARLY IN THE PERIOD. THE FRONT WILL ADVANCE SEWD AND
OFF THE ATLANTIC SEABOARD TRAILING SWWD INTO NRN FL BY EARLY
EVENING.
...ERN CAROLINAS AND SERN VA...
BOUNDARY LAYER FLOW WILL VEER TO WLY AND WEAKEN IN WAKE OF LEAD
SHORTWAVE TROUGH THAT WILL MOVE OFFSHORE EARLY FRIDAY. THIS WILL
LIMIT THE RETURN OF RICHER LOW LEVEL MOISTURE RESIDING ACROSS THE
CNTRL AND NERN GULF COASTAL AREA. EXISTING MOISTURE WITH DEWPOINTS
GENERALLY FROM 60-64 WILL PERSIST IN THIS REGION. THIS ALONG WITH
DIABATIC HEATING WILL CONTRIBUTE TO DESTABILIZATION...BUT WEAK MID
LEVEL LAPSE RATES WILL LIMIT MLCAPE TO AOB 800 J/KG. THE MARGINAL
THERMODYNAMIC ENVIRONMENT WILL SERVE AS A PRIMARY LIMITING FACTOR
FOR A MORE ROBUST SEVERE THREAT.
AS THE BOUNDARY LAYER DESTABILIZES...POTENTIAL WILL EXIST FOR
ADDITIONAL STORMS TO DEVELOP ALONG SEWD ADVANCING COLD FRONT. THE
STRONGER Q-G FORCING ATTENDING THE AMPLIFYING UPPER TROUGH WILL
PROBABLY REMAIN IN POST FRONTAL ZONE. THIS SUGGESTS DEEP CONVERGENCE
AND THUNDERSTORM COVERAGE ALONG OR AHEAD OF THE FRONT MAY REMAIN
SOMEWHAT LIMITED. DESPITE THE MODEST AND VEERED LOW LEVEL
FLOW...BULK SHEAR OF 40-50 KT WILL EXIST IN PRE-FRONTAL WARM SECTOR.
STEEPENING LOW LEVEL LAPSE RATES WILL SUPPORT A THREAT OF MAINLY
ISOLATED STRONG-DAMAGING WIND GUSTS WITH ANY STORMS THAT DEVELOP
DURING THE AFTERNOON.
...FL PANHANDLE AND NRN FL THROUGH S GA...
PLUME OF DEEP SUBTROPICAL MOISTURE IS SHIFTING EWD INTO THIS REGION.
OBSERVED DATA SHOWS CONVECTION INCREASING WITHIN THIS
PLUME...ESPECIALLY OVER THE WRN GULF WHERE A SHORTWAVE TROUGH IS
LIKELY LIFTING NEWD THROUGH SRN BRANCH OF WLYS. WIDESPREAD CLOUDS
AND CONVECTION WILL LIKELY SPREAD NEWD THROUGH THE NERN GULF BY
EARLY FRIDAY...WITH WEAK MID LEVEL LAPSE RATES AND LIMITED POTENTIAL
FOR DESTABILIZATION. HOWEVER...RICH LOW LEVEL MOISTURE ALREADY IN
PLACE WITH NEAR 70 DEWPOINTS WILL RESULT IN AT LEAST MARGINAL
INSTABILITY WITH ANY AMOUNT OF HEATING.
MODELS DO INCREASE THE WSWLY LOW LEVEL WINDS...MOST LIKELY IN
RESPONSE TO APPROACHING SRN BRANCH SHORTWAVE TROUGH. THE GFS IS THE
STRONGEST WITH THIS FEATURE...BUT APPEARS A BIT OVERDONE BY
CONVECTIVE FEEDBACK. MODERATELY STRONG WSLY DEEP LAYER FLOW WITH 35
TO 40 KT BULK SHEAR WOULD SUPPORT A THREAT FOR ORGANIZED STORMS AND
MAINLY ISOLATED DAMAGING WIND IF SOME OF THIS MOMENTUM COULD BE
BROUGHT DOWN TO THE SURFACE. THREAT IS CONDITIONAL GIVEN EXPECTED
WIDESPREAD CLOUD COVER AND LIMITED POTENTIAL FOR DESTABILIZATION.
WILL CARRY LOW SEVERE PROBABILITIES FOR NOW. IF IT BEGINS TO APPEAR
MORE INSTABILITY WILL DEVELOP THAN CURRENTLY ANTICIPATED...A SLIGHT
RISK MAY BE REINTRODUCED IN LATER OUTLOOKS.
..DIAL/HURLBUT.. 05/16/2008
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