Flash Flood Warning 63, NWS State College, PA

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
205 PM EDT THU JUL 27 1995

...SHORT TERM...
TRW DVLG IN WRN PA ATTM WHERE ADAP SHOWS LI/S TO -9. LEFT-OVER
OUTFLO FROM THIS MORN/S CONVTN (SEEN ON ERLR VSBL IMAGERY) POSSBLY
HAS TRIGGERED CONVTN. WV IMAGERY CONTS TO SHOW EWRD PROGRESSION OF
UPR LVL S/W TWD PA ALSO HELPING SUPPORT CONVTN. THIS MORN/S 500 MB
UPR AIR CHART AND 12Z MODEL RUNS SHOWS COOLER AIR AT 500 MB
PRECEDING S/W TROF AXIS WHICH WAS STEEPENING LAPSE RATES ACRS WRN
PA ATTM. LATEST ADAP CHARTS SHOW BEST SFC MOISTURE CONV TO THE E OF
THIS DVLPG CONVTN IN CNTRL PA WHICH SUGGESTS ACVTY WILL HOLD
TOGETHER AND CONT TO DVLP AS IT MOVS INTO CNTRL PA. SLIGHTLY MORE
STBL AIR ACRS CNTRL PA WITH DWPTS IN THE UPR 60S WON/T HELP BUT
SHUD STILL BE ENUF TO SUPPORT CNVTN LATE AFTRN/ERLY EVE INTO
CNTRL/ERN PA. WUD CONT LIKELY POPS TRW THIS EVE CNTRL PA.

...LONGER TERM...
MODELS ALL INDICATE THAT THIS S/W SLOWS DOWN AND GETS SHEARED OUT
AS IT TRYS TO IMPINGE ON UPR HI OFFSHORE TONIGHT. MODELS SHOW THAT
A LO-LVL SRLY WIND MAX DVLPS AHEAD OF THIS UPR LVL S/W E OF MTNS BY
00Z WHICH MAY HELP FOCUS CONVTN MORE. AT THE SAME TIME... THE NERN
U.S LIES IN THE RIGHT ENTR REGION OF AN UPR LVL JET WHICH WILL
ENHANCE UPR LVL DVRG ACRS THE REGION ABV THIS LO-LVL CONV REGION.
PLENTY OF MOSITURE ARND...  PWATS RUNNING NR 2.0 INCHES IN LWR SUS
VLLY AT 00Z ON ETA/NGM (NO AVN GRIDS YET) AND WV VAPOR IMAGERY
CONTINUES TO SHOW MOIST SWRLY FLO ARND UPR HI CIRCU. THINK CNTVN
THAT IS FORMING IN WRN PA WILL MOV INTO ERN PA LATER THIS EVE AND
CUD BECOME A HVY RAIN EVENT FOR LWR SUS VLLY. WUD CONSIDER HI POPS
LWR SUS VLLY AND MENTION OF HVY DOWNPOURS IN FCST.

THIS INITIAL S/W WILL OUTRUN SFC FRNT/PRES TROF THAT CURRENTLY RAIN
ACRS LWR MI-IL. BOTH ETA/NGM ALL INDICATE AN AMPLIFICATION OF THE
UPR LVL RDG ACRS THE GREAT LAKES IN RESPONSE TO WAA AHEAD OF A
DVLPG STORM IN SC CANADA. WITH THE RDG BUILDING IN THE GREAT LAKES
REGION... NEXT VORT LOBE RIDING ON TOP OF UPR RDG WILL DIVE A
LITTLE FURTHER S BEING THE IMPETUS TO PUSH THIS FRNT/PRES TROF ACRS
ST. MODELS DIFFER IN TIMING WITH NGM MOST AGRESSIVE. ETA A LITTLE
SLOWER. LIKE ETA SINCE FRNT AND DRYER AIR LIKELY WILL HV A HARD
TIME MAKING ANY PROGRESS E OF MTNS. WUD GO CHC POPS WRN/CNTRL CTP
FA SAT AND KEEP POPS OUT SUS VLLY UNTIL EVE HRS AS FRNT TENDS TO
GET HUNG UP.

WILL MONITOR 88D NO ZONES.
PFT/S OUT.

NICOSIA