Flash Flood Warning 227, NWS State College, PA

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
750 PM EST SUN DEC 1 1996

...ZONE SUGGESTIONS/COORDINATION...
...PIT...FRONT SEEMS TO BE HANGING UP FOR THE TIME BEING OVER
HUNTINGDON/BEDFORD COUNTIES. WUD WAIT TIL THE BITTER END TO DECIDE
WHERE OR NOT TO LET FFA EXPIRE THESE COUNTIES. STILL THINK BEST
RAINS WILL BE FURTHER EAST...BUT LONG DURATION TOTALS MAY CAUSE
PROBLEMS IF FRONT DOESN'T START TO HAUL SOON.
...PHL...WUD LET FFA REMAIN UNTIL WAVE MOVES OFF DURING WEE HOURS.

...DISCUSSION...
FIRST PROBLEM CONCERNS FRONT PASSING THRU LOCAL AREA AND HEAVY RAIN
ASSOC. GENERAL 1-2" TOTALS FROM EARLIER TODAY BEING ADDED ON TO BY
FRONTAL PRECIP. SMALL STREAMS IN SCHUYLKILL AND LANCASTER OUT OF
BANKS AND SEVERAL OTHER LOCATIONS NEAR FLASH FLOOD GUID. FEEL
THREAT OF FLOODING WILL PRETTY MUCH CONFINE ITSELF TO SE COUNTIES
WHERE MORE HEAVY PRECIP IS POSSIBLE FROM UPSTREAM DEVELOPMENTS. IR
SHOT SHOWS ANTICYCLONIC BULGE ON BACK SIDE OF BAROCLINIC ZONE AND
LAST FEW FRAMES DEPICT RAPID ENHANCEMENT IN COLD CLOUD TOPS. RADAR
SHOWS PRECIP BLOSSOMING BACK INTO SOUTH CTRL PA WITH SOME HITS
SHOWING UP ON LDS CHARTS. ALL OF WHICH SEEM TO SUPPORT MODEL
GUIDANCE OF INCIPIENT CYCLOGENESIS OVER W.VA. ADAP SHOWS GOOD
PRESSURE FALLS OVER ERN PA IN STRONG WARM ADVECTING FLOW.
DEVELOPMENT SEEMS TO BE IN RESPONSE TO JET STREAK THAT MESO ETA
PROGS TO APPROACH FRONTAL ZONE. AS LEFT FRONT QUAD SLIDES INTO
REGION FROM SOUTH...COUPLED JET FEATURE DEVELOPS AND GETS NEW
ENTICES NEW WAVE TO FORM ON FRONT...EVENTUALLY TO MOVE TWD NJ AND
SRN NEW ENG.

AFTER DEALING WITH POTENTIAL FLOODING PROBLEMS...SEVERE WX BECOMES
THREAT AS STRONG ENVIRONMENTAL WINDS JUST OFF DECK MANAGE TO MIX
DOWN TO SFC UNDER FORCING FROM DEVELOPING CONVECTION. WARNING WAS
ISSUED FOR BEDFORD COUNTY AS SRM PRODUCT SHOWED QUICK TIGHTEN UP OF
SHEAR OVER COURSE OF 3 VOL SCANS IN SE QUAD OF THUNDERSTORM HEADING
UP OUT OF MD. NOT ABLE TO CONFIRM DAMAGE AS YET BUT QUICK HITTING
NATURE OF STORMS WILL BE HARD TO GET AHEAD OF.

MESO ETA SHOWS COLD AIR ACCELERATING EASTWARD AS WAVE DEEPENS AND
MOVES OFF TO EAST. HOURLY PRECIP PLOTS DON'T SHOW MUCH SNOW BUT
LARGE SCALE GRIDS HINT AT POSSIBILITY THAT SOME PRECIP MAY HANG
BACK AS COLD AIR INVADES. NOT THE BEST SET UP FOR ACCUM SNOW AS
MOISTURE AND VERTICAL VELOCITIES WILL BE SHUTTING DOWN QUICKLY AND
COLD AIR IS STILL A WAYS OFF...BUT COULD GET SLIPPERY TWD MORNING.

NEXT SYSTEM IS ZIPPED EAST BY MODELS POSSIBLY SPREADING LIGHT
PRECIP IN HERE TUES. TROF MAINTAINS LOW AMPLITUDE SO PRECIP AMOUNTS
SHUD REMAIN MINOR. ITS LATER IN WEEK THAT LOOKS MORE WINTERY. UKMET
AND ECMWF CAN'T AGREE ON PLACEMENT OR TIMING BUT EACH PAINTS ITS
OWN SCENARIO FOR MAJOR ERN US CYCLOGENESIS. MRF PAINTS ZONAL FLOW
AND THAT SEEMS TO BE WHAT NCEP ACCEPTS IN HAND DRAWN PROGS. WEATHER
COULD GET WORTH LOOKING FORWARD TOO HERE AS PATTERN UNDERGOES
TRANSITION.

...LAKE SNOW OUTLOOK...
SUN MIDNIGHT TO 7AM...N...
MON 7AM TO 7PM...N...
MON 7PM TO 7AM...N...

LA CORTE