Flash Flood Warning 5, NWS State College, PA

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
2 AM EST SUN MAR 2 1997

...ZONE SUGGESTION...
FOR TODAY...
STEADY RAIN WILL END THIS MORNING AND NEEDS TO BE CUT BACK
TIMING-WISE IN WRN CTP ZONES. ALSO... DON/T THINK TSRA IS PSBL
THIS MORNING WHEN FRNT GOES THRU GIVEN THE WEDGE OF VERY STBL AIR
STUCK E OF THE MTNS. WUD HV SCATTERED SHOWERS FOR THIS AFTRN ACRS
THE NRN/WRN MTNS. THUS... RAIN TAPERING TO SCATTERED SHOWERS WILL
WORK IN THE WRN/NRN ZONES. RAIN ENDING THIS MORNING SUS VLLY C/SC
MTNS. PARTIAL CLEARING SUS VLLY ONLY. MO CLDY POINTS W.
ZONES LOOK GOOD TONIGHT/MONDAY.

...DISCUSSION...
BASE REFLECTIVITY LOOPS FROM KPBZ/KCCX AND KCLE SHOWS THAT A
SWRLY CONVEYOR BELT OF PRECIP WAS OVERTAKING PA WHICH CORRELATED
WELL TO THE 850 MB LOW-LVL JET STREAM SEEN ON THE UPR AIR ANLYS.
THE DYNAMIC SET-UP WAS FAVORABLE FOR WIDESPREAD RAINS IN PA... AN
UPR LVL JET AXIS TO OUR NORTH W/ DVRG ALOFT AND A LOW-LVL JET S
OF PA SUPPORTG BROAD-SCALE CONV. AT THIS TIME... THE HEAVIEST
PRECIP IN CWA WAS MOVG ACRS NC PA WITH ANTHR BATCH WORKG INTO SW
PA FROM OH. WV IMAGERY SHOWS TWO SMALLER SCALE WAVES RIDING NEWRD
WITHIN THIS CONVEYOR BELT WHICH WAS SUPPORTG THE ENHANCED PRECIP
IN NW PA AND THE OTHR BATCH INTO OH/SW PA. THESE SMALLER SCALE
FEATURES WILL CONTINUE TO RIPPLE NEWRD WITHIN THE PRECIP CONVEYOR
BELT THIS MORNING. THE ETA SOLTN SUGGESTS THAT LITTLE PRECIP
REACHES ERN PA WITH THE BULK OF THE HEAVIEST RAINS IN WRN PA. THE
SWRLY LOW-LVL FLO WAS SUBSIDING OFF THE HIGHER MTNS IN WVA AND
CUTTING OFF PRECIP FOR SUS VLLY ATTM. THIS IS A COMMON EFFECT AND
I HAVE SEEN IT MANY TIMES. THUS... LESS RAINS FOR SUS VLLY.

THE TIME LAPSES OF KPBZ AND KCLE BASE REF SUGGESTS THAT THE BACK-
EDGE OF THE LARGE PRECIP MASS OVR OH WAS NOW BEGINING TO SHIFT
EWRD RATHER QUICKLY. THIS WILL CONTINUE TO BE THE TREND AS THE CD
FRNT BEGINS TO PUSH E INTO PA OVRNGT. THE PRECIP CONVEYOR BELT
WAS PRE-FRONTAL AND I EXPECT IT TO REMAIN THAT WAY FOR THE MOST
PART. THE HEAVY RAIN THREAT FOR WRN CTP CWA SHUD END W/ FROPA
WHICH OCCURS BY 1200 UTC. GIVEN THE SUBSDC OFF APPLCNS ACRS C/E
PA... PRECIP SHIELD WILL ALSO SHRINK AS IT MOVES INTO ERN PA.
ETA/S IDEA OF PRECIP BREAKING UP LOOKS GOOD. AS FOR FFA... THINK
IT PROBABLY SHUD BE KEPT UP FOR THIS MORNING... AND WE CAN CLEAR
IT PIECE-MEAL FOR COUNTIES WHEN RADAR INDICATES THAT THE HEAVIER
PRECIP IS OVER.

AFTER FROPA... LOW-LVL MOISTURE WILL BE COPIOUS ACRS PA AS IT
GETS TRAPPED UNDER SUBSDC INV NEAR 850 MB. MODEL SOUNDINGS HV A
LAYER OF NEAR SATURATION UNDERNEATH THE SUBSDC INV WITH NW FLO
RUNNING INTO THE MTNS. THUS... SEE SCATTERED SHWRS THIS AFTRN FOR
MTNS OF NRN AND WRN PA AFTER THE STEADY RAIN ENDS. SUBSDC OFF
MTNS OF PA WILL TEND TO CLR SUS VLLY BY AFTRN. SOME DECENT WINDS
CUD DVLP LATER IN THE AFTRN AS CAA INCREASES. AT THIS POINT... I
WUD HV WINDS INCREASING TO 15 TO 25 MPH AND GUSTY ALL ZONES...
AND HV 20 TO 30 MPH FOR LAURELS.

FOR TONIGHT... HI PRES BUILDS IN FROM THE N AND WINDS TURN MORE
ERLY BY MONDAY. ZONES LOOKS PRETTY GOOD FOR NOW AS TO CLOUD-
COVER.

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

NICOvSIA