Rusty Shackleford
Automotive M.D.
Sure seems like it. Possibility is growing for some heavy-duty shit in PA tomorrow. And this is just as of this morning. We all know how it can build, or die, within a moment's notice:
http://forecast.weather.gov/product...&format=CI&version=1&glossary=1&highlight=off.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
FRIDAY IS SHAPING UP TO BE A VERY ACTIVE WEATHER DAY IN CENTRAL
PA WITH A DUAL HEAVY RAIN/SVR WX THREAT UNFOLDING...AS THE COLD
FRONT CROSSES THE CENTRAL APPLCHNS. THE MID-UPPER LOW WILL TREND
TOWARD A SLIGHT NEGATIVE TILT...WITH A STRENGTHENING BELT OF DEEP
LAYER/MOIST SWLY FLOW OVERSPREADING MUCH OF THE EASTERN U.S IN
ADVANCE OF THE SHARP COLD FRONT.
EARLY MORNING LLVL STABILITY/POS LI/S VIA PRESSURE DRIVEN
CHANNELING AND ESE MARITIME FLOW WILL ERODE FROM SOUTH TO NORTH AS
WARM FNT LIFTS NEWD THRU THE DAY. MODEL DATA INDICATES A DIURNALLY
DESTABILIZING BOUNDARY LAYER IN THE WARM SECTOR SOUTH OF THE WARM
FNT AND AHEAD OF APPROACHING COLD FNT. PRE-FRONTAL INSOLATION
SHOULD LEAD TO MODERATE INSTABILITY /1000-2000 J PER KG ML CAPE/
GIVEN INCREASINGLY MOIST BLYR WITH SFC DEWPOINTS SURGING INTO THE
60S. AMPLE LG SCALE FORCING...DEEP LYR SHEAR AND CAPE WILL
CONTRIBUTE TO ORGANIZED TSTM DEVELOPMENT ALONG/AHEAD OF THE COLD
FRONT...WITH HEAVY DOWNPOURS AND INTENSE RAIN RATES LKLY GIVEN
ABV NORMAL PWATS AND +3-4SD V-WINDS. 1-3HR FFG IS GENERALLY BTWN
1.5-3 INCHES AND SYSTEM SHOULD BE PROGRESSIVE. THEREFORE THREAT OF
FLOODING WILL BE LOCALIZED.
SPC HAS BASICALLY CARRIED OVER THE DY3 SLGT RISK AREA INTO DY2
WHICH ESSENTIALLY COVERS FROM I-80 SOUTH TO THE MD LINE. WHILE THE
PRIMARY SEVERE WEATHER HAZARDS ARE EXPECTED TO BE DAMAGING WINDS
AND LARGE HAIL FROM WHAT SHOULD BE A MAINLY LINEAR CONVECTIVE
MODE...THERE WILL BE AN ELEVATED-CONDITIONAL THREAT FOR ISOLATED
TORNADOES OVER S-CENTRAL AND SERN PA. THE FAVORABLE TORNADO
INGREDIENTS ARE FCST TO BE IN PLACE...INCLUDING 20-30KT 0-1KM
SHEAR AND 0-3KM EHI VALUES BTWN 2-4 M2/S2. 0-1KM SHEAR HAS SHOWN
TO DELINEATE TORNADIC VS. NON-TORNADIC ENVIRONMENTS IN CENTRAL PA.
THE CONDITIONAL THREAT ARISES FROM 1) SUFFICIENT WARM SECTOR
DESTABILIZATION NEAR/SOUTH OF WARM FNT AND 2) SEMI-DISCRETE
SUPERCELLULAR DEVELOPMENT OCCURRING OUT AHEAD OF COLD FNT WHERE
CONVECTIVE MODE SHOULD BE MORE LINEAR. WOULD NOT BE SURPRISED IF
S-CENTRAL/SERN PA IS UPGRADED TO A CATG MODERATE RISK EITHER LATER
TODAY OR ON DY1...WHICH IS SUGGESTED IN THE SPC DY2 OUTLOOK.
THE COLD FNT SHOULD CLEAR THE WRN 1/2 OF THE CWA BY 00Z AND BE
EXITING ERN PA AROUND DAY BREAK SAT. DRY SLOT SHOULD CUT OFF PCPN
ABRUPTLY BEHIND THE FNT WITH ONLY A LOW CHC FOR ISOLD-SCT SHOWERS.