SPC AC 041723
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT FRI APR 04 2008
VALID 051200Z - 061200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CAROLINAS SWWD INTO
NRN FL...
...SYNOPSIS...
A PROGRESSIVE AND BROADLY CYCLONIC LARGE-SCALE PATTERN WILL PERSIST
OVER THE CONUS DURING THE DAY TWO PERIOD. SHORT WAVE TROUGH
INITIALLY OVER THE LOWER MS VALLEY IS FORECAST TO WEAKEN WHILE
LIFTING NEWD TOWARD THE MIDDLE ATLANTIC COAST. MEANWHILE...
UPSTREAM SYSTEM OVER THE NRN INTERMOUNTAIN REGION WILL TRANSLATE EWD
INTO THE NRN HIGH PLAINS.
IN THE LOW LEVELS...BAROCLINIC ZONE ATTENDANT TO SERN U.S. SHORT
WAVE TROUGH WILL ADVANCE EWD ACROSS THE CNTRL AND ERN GULF STATES
WITH A SURFACE WAVE DEVELOPING NEWD ALONG THE FRONT ACROSS GA INTO
THE CAROLINAS. OVER THE PLAINS...LEE CYCLONE OVER SERN MT/WY WILL
DEVELOP GENERALLY EWD OR SEWD INTO SD ALONG RETREATING WARM FRONT.
TRAILING COLD FRONT WILL CONCURRENTLY PUSH EWD/SEWD THROUGH THE
NRN/CNTRL ROCKIES AND NRN/CNTRL HIGH PLAINS.
...CAROLINAS INTO ERN GULF STATES...
SWLY LLJ ASSOCIATED WITH WEAKENING SHORT WAVE TROUGH WILL MAINTAIN A
MOIST LOW-LEVEL AIR MASS AHEAD OF COLD FRONT WITH DEWPOINTS OF 65 TO
70F. DESPITE RELATIVELY POOR MIDLEVEL LAPSE RATES OF AROUND 6-6.5
C/KM...THIS MOISTURE WILL LARGELY CONTRIBUTE TO POCKETS OF MODERATE
INSTABILITY WHERE MLCAPES MAY APPROACH 1000-1500 J/KG.
CLUSTERS OF TSTMS OR A QUASI-LINEAR MCS WILL LIKELY BE ONGOING
SATURDAY MORNING EITHER ALONG COLD FRONT OR PRE-FRONTAL CONFLUENCE
BAND. FORCING FOR ASCENT IN RIGHT ENTRANCE REGION OF DEPARTING JET
STREAK COUPLED WITH WEAK HEIGHT FALLS AHEAD OF SHORT WAVE TROUGH
SHOULD MAINTAIN THIS ACTIVITY EWD ACROSS THE WARM SECTOR WITH STORMS
INCREASING IN COVERAGE AND INTENSITY BY AFTERNOON AS AIR MASS
DESTABILIZES.
WHILE DEEP-LAYER SHEAR WILL REMAIN SOMEWHAT MARGINAL /35-40 KT/ AND
CONFINED TO ALONG FRONT...THE PERSISTENT LLJ WILL MAINTAIN A
CORRIDOR OF STRONGER LOW-LEVEL SHEAR OVER A BROADER AREA OF THE WARM
SECTOR. THIS IS ESPECIALLY THE CASE IF A MORE SUBSTANTIAL SURFACE
WAVE BECOMES ESTABLISHED ALONG FRONTAL ZONE. THUS... POTENTIAL WILL
EXIST FOR SUPERCELL AND BOWING STRUCTURES EMBEDDED IN LARGER
CONVECTIVE PRECIPITATION SHIELD. THE MORE INTENSE STORMS WILL BE
CAPABLE OF DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES.
THE POTENTIAL FOR MAINLY LOCALLY DAMAGING WINDS WILL EXTEND SWD
ALONG WRN FL SEA BREEZE BOUNDARY WHICH SHOULD DEVELOP INTO INTERIOR
PORTIONS OF THE PENINSULA SATURDAY AFTERNOON.
...SD/MN...
LOW-LEVEL MOISTURE IS EXPECTED TO REMAIN QUITE LIMITED S OF WARM
FRONT AND AHEAD OF DEVELOPING SURFACE LOW WITH DEWPOINTS IN THE 30S
TO LOWER 40S. HOWEVER...A PLUME OF STEEP MIDLEVEL LAPSE RATES
ORIGINATING OVER THE CNTRL ROCKIES WILL PRECEDE UPPER SHORT WAVE
TROUGH...CONTRIBUTING TO A WEAKLY UNSTABLE AIR MASS.
ISOLATED/SCATTERED TSTMS WILL BECOME INCREASINGLY LIKELY LATE
SATURDAY AFTERNOON INTO SATURDAY EVENING MAINLY FROM VICINITY OF
SURFACE LOW TO ALONG AND N OF WARM FRONT WHERE LOW-LEVEL WAA AND
ISENTROPIC ASCENT WILL BE FOCUSED. A FEW OF THE MORE INTENSE STORMS
WILL BE CAPABLE OF SMALL HAIL GIVEN THE COOL THERMODYNAMIC PROFILES.
NO SEVERE WEATHER IS EXPECTED ATTM.
..MEAD.. 04/04/2008
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0800Z
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