SWODY1
SPC AC 300537
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CDT MON JUL 30 2007
VALID 301200Z - 311200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
FULL-LATITUDE TROUGHING WILL PERSIST THROUGH THE PERIOD OVER ERN N.
AMERICA WHILE UPSTREAM HIGH IS MAINTAINED OVER THE CNTRL PART OF THE
NATION. IN THE LOW-LEVELS...SYNOPTIC FRONT ATTENDANT TO ERN U.S.
TROUGH WILL REMAIN QUASI-STATIONARY FROM THE SC COAST WWD THROUGH
THE GULF COAST STATES AND THEN MORE NWWD INTO THE ARKLATEX.
ELSEWHERE...WEAK COLD FRONT OR PRESSURE TROUGH WILL EXTEND FROM
MIGRATORY SURFACE LOW OVER SK/MB SWWD INTO THE NRN INTERMOUNTAIN
REGION.
..SERN ATLANTIC COAST INTO THE ARKLATEX...
A VERY MOIST BOUNDARY LAYER WILL BE MAINTAINED AHEAD OF PRIMARY
SURFACE BOUNDARY WITH DEWPOINTS OF 70-75 F. MID-LEVEL LAPSE RATES
WILL REMAIN QUITE WEAK...THOUGH THIS MOISTURE COUPLED WITH DAYTIME
HEATING SHOULD CONTRIBUTE TO MLCAPES APPROACHING 1500-2500 J/KG.
LATEST SHORT TERM MODEL GUIDANCE SUGGESTS THAT A WEAK SHORT WAVE
TROUGH WILL ROTATE SEWD THROUGH MEAN TROUGH BASE...WITH WEAK HEIGHT
FALLS OVERSPREADING THE CAROLINAS AND ERN GA NEAR THE TIME OF PEAK
HEATING. SUBTLE FORCING FOR ASCENT ASSOCIATED WITH THIS FEATURE
COUPLED WITH THE PRESENCE OF THE PRIMARY FRONT AND REMNANT OUTFLOW
BOUNDARIES SHOULD CONTRIBUTE TO THE DEVELOPMENT OF NUMEROUS
TSTMS/TSTM CLUSTERS THROUGH THE AFTERNOON.
SOME ENHANCEMENT OF MID AND HIGH-LEVEL FLOW MAY ACCOMPANY THIS SHORT
WAVE TROUGH...THOUGH DEEP LAYER BULK SHEAR WILL REMAIN RELATIVELY
WEAK AND GENERALLY BELOW 30 KT IN THE LOWEST 6 KM. AS SUCH...STORM
MODE WILL LIKELY BE MULTICELL CLUSTERS AND/OR PULSE WITH A THREAT OF
DAMAGING WET MICROBURSTS AND PERHAPS SOME HAIL.
FARTHER W...LARGE-SCALE FORCING WILL REMAIN NEGLIGIBLE...THOUGH
CONVERGENCE ALONG FRONT SHOULD BE SUFFICIENT TO INITIATE STORMS
GIVEN THE WEAKLY CAPPED AIR MASS. HERE TOO...PRIMARY SEVERE THREAT
WILL BE ISOLATED STRONG WIND GUSTS WITH THE MORE INTENSE CONVECTION.
..NRN INTERMOUNTAIN REGION...
STEEP LOW TO MID-LEVEL LAPSE RATES AND PWS OF .7-.9 INCH ARE
EXPECTED TO CONTRIBUTE TO POCKETS OF MODEST INSTABILITY /MLCAPES OF
500-1000 J PER KG/ LATER TODAY OVER THE SRN BITTERROOTS. FORCING
FOR ASCENT ATTENDANT TO SUBTLE SHORT WAVE TROUGH LIFTING NEWD
THROUGH THE REGION IN CONJUNCTION WITH DEEPENING OROGRAPHIC
CIRCULATIONS SHOULD SUPPORT THE DEVELOPMENT OF ISOLATED TO SCATTERED
TSTMS BY LATE AFTERNOON. FORECAST SOUNDINGS INDICATE THE PRESENCE
OF A RELATIVELY DEEP AND WELL MIXED BOUNDARY LAYER WITH 30-35 KT OF
DEEP LAYER SHEAR. THIS TYPE OF ENVIRONMENT WILL BE SUPPORTIVE OF A
FEW STRONG/POTENTIALLY SEVERE STORMS CAPABLE OF HAIL AND LOCALLY
STRONG WIND GUSTS THROUGH THE EVENING HOURS.
..AZ...
MID AND UPPER-LEVEL LOW OVER CHIHUAHUA MEXICO IS FORECAST TO BECOME
INCREASINGLY SHEARED IN W-E FASHION THROUGH THE PERIOD WITH A SLIGHT
INCREASE IN ELY MID-LEVEL FLOW DEVELOPING ACROSS THE SRN HALF OF THE
STATE. WHILE MID-LEVEL LAPSE RATES ARE NOT EXPECTED TO BE
PARTICULARLY STEEP...DIABATIC HEATING COUPLED WITH BOUNDARY LAYER
DEWPOINTS IN THE 50S TO LOWER 60S WILL CONTRIBUTE TO MLCAPES OF
500-1000 J/KG. TSTMS SHOULD AGAIN DEVELOP OVER THE HIGHER TERRAIN
BEFORE MOVING/DEVELOPING WWD/SWWD INTO THE LOWER DESERTS. A FEW OF
THE MORE INTENSE STORMS WILL BE CAPABLE OF SOME HAIL...BUT MORE SO
LOCALLY STRONG WIND GUSTS.
.MEAD/BOTHWELL.. 07/30/2007
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