National Weather Service ------------------------------------------------------------------------ FPUS03 KCTP 290641 AFDCTP CENTRAL PENNSYLVANIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 245 AM EDT FRI MAY 29 1998 ...WRKZONES SENT TO PIT/PHL VIA PHLADMCTP... ...DISCUSSION... WILL HAVE TO WATCH CONVECTION OVER THE SOUTHERN GREAT LAKES AREA EARLY THIS MORNING. MODELS SHOW A WEAKENING AREA OF INSTABILITY TRACKING FROM LOWER MI EAST TO WESTERN NY THIS MORNING. SAT LOOPS SHOW CLOUD TOPS ARE WARMING AS STRONGEST CONVECTION SHIFTS BACK TO THE WEST WITH BEST LOW-LVL JET AND THETA-E AXIS. EXPECT A WEAKENING AREA OF RW/TRW TO TRACK ACROSS LK ERIE EARLY THIS MORNING...AND COULD POSSIBLY SURVIVE AS FAR EAST AS THE NW PART OF THE CWA BEFORE DYING OUT. SCATTERED THUNDERSTORMS WILL REDEVELOP THIS AFTERNOON AS A CDFNT APPROACHES ALONG WITH A WEAK UPPER SHORT-WAVE. BEST LIFT WILL BE ACROSS THE NORTHERN PART OF THE CWA THIS AFTERNOON...MOST INSTABILITY WILL BE ACROSS THE SE. MODELS SHOWING THEIR USUAL BIASES...WITH THE ETA FORECASTING MID 60S DEW PTS RESULTING IN LI'S FALLING TO THE -4 TO -7 RANGE AND CAPES FROM 1000 TO 2000 J/KG. MEANWHILE...THE NGM FORECASTS DEW PTS IN THE UPPER 50S...WITH CORRESPONDINGLY LESS IMPRESSIVE STABILITY INDICIES. A COMPROMISE BETWEEN THE NGM AND ETA INDICATES MODERATE INSTABILITY TODAY. WILL GO WITH LIKELY POPS ACROSS THE NORTH AND CHC POPS CENTRAL AND SOUTH BASED ON BETTER DYNAMICS ACROSS THE NORTH. THE COMBINATION OF MODERATE INSTABILITY...AND MODEST SPEED SHEAR...WITH LITTLE IF ANY DIRECTIONAL SHEAR...COULD PRODUCE SOME ISOLATED SEVERE STORMS THIS AFTERNOON WITH DAMAGING WINDS FROM BOW ECHOES THE MAIN THREAT. 940 SHOWS A SLIGHT RISK FOR SEVERE WEATHER ACROSS MOST OF PA TODAY AND WILL ISSUE AN SPS TO COVER FOR THIS. 850-MB TEMPERATURES WILL BE AROUND 2 DEGREES C HIGHER TODAY THAN YESTERDAY SO EXPECT HIGHS OF 3 TO 6 DEGREES F HIGHER...IE MID 80S TO AROUND 90. MODELS INDICATE MOISTURE RETURNING QUICKLY TO THE OHIO VALLEY / GREAT LAKES SATURDAY...WITH WAA TYPE NOCTURNAL RW/TRW POSSIBLE AS SOON AS SATURDAY NIGHT...ESPECIALLY ACROSS THE NORTH. WILL MENTION INCREASING CLOUDS ACROSS THE NW SATURDAY AFTERNOON...BUT THE REST OF THE CWA SHOULD REMAIN SUNNY THROUGH SATURDAY. MSE NNNN ------------------------------------------------------------------------ FPUS3 KPHL 290638 SFDPHL STATE FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 230 AM EDT FRI MAY 29 1998 THE ONLY TWO COUNTIES IN THE FOG ADVISORY THAT DO NOT CURRENTLY HAVE FOG...OR AT LEAST VERY LOW CIGS...ARE MONMOUTH NJ AND TALBOT MD. WITH CONDITIONS EXPECTED TO CONTINUE TO LOWER DURING THE NEXT FOUR HOURS OR SO...WE/LL KEEP THE ADVISORY IN PLACE. WE ALREADY HAVE DENSE FOG INDICATED AT ACY AND WWD. BASED ON SATELLITE DATA...THE LOW CLOUDS/FOG SHOULD ADVECT UP INTO MONMOUTH COUNTY...LEAVING THE ONLY QUESTIONABLE ADVISORY LOCATION BEING TALBOT COUNTY. THE TSTM COMPLEX NOW MAKING IT/S WAY ACROSS LOWER MI WILL CONTINUE TO PUSH TO THE E AND IT SHOULD WEAKEN THIS MORNING. NEVERTHELESS ...IT WILL LEAVE SOME FAIRLY IMPRESSIVE OUTFLOW BOUNDARIES IN ITS WAKE. THE ONE PUSHING ACROSS NERN IN AND INTO NWRN OH PRODUCED A GUST TO 38 KTS AS IT PASSED THROUGH SBN ABOUT 100 AM. THE LEFTOVER BOUNDARIES SHOULD PROVIDE A GOOD FOCUS FOR CONVECTIVE DEVELOPMENT TO THE N AND W OF OUR FORECAST AREA AS WE APPROACH AND GET INTO THE EARLY AFTERNOON HOURS...WITH TEMPS WARMING WELL INTO THE 80S BY THAT TIME. THE ETA INDICATES A SURFACE TROUGH EXTENDING SW FROM ABOUT PORT JERVIS NY TO ABE AND LNS AT 00 UTC. THE NGM AND AVN SEEM A LITTLE SLOWER WITH THIS FEATURE. HOWEVER...WITH A NUMBER OF SURFACE BOUNDARIES AROUND...IT IS NOT CLEAR AS TO WHICH...IF ANY...MODEL IS KEYING IN ON THE CORRECT ONES. BASED ON THE ETA SCENARIO...WHICH APPEARS TO BRING THE THREAT OF CONVECTION TO THE S FASTER THAN THE OTHERS...IT SEEMS SAFE TO CONFINE THE CHANCE POPS TO JUST THIS EVENING IN PHL AND IN POINTS TO THE E AND S. THIS WOULD COVER THE SITUATION EVEN IF SOMETHING WERE TO AFFECT THOSE AREAS AROUND 600 OR 700 PM. FOR OUR ZONES TO THE N AND W...WE/LL MAINTAIN CHANCE POPS FOR BOTH THIS AFTERNOON AND THIS EVENING. AS FAR AS SAT IS CONCERNED...IT IS QUESTIONABLE AS TO WHETHER THE "COLD FRONT" WILL SINK AS FAR TO THE S AS THE NGM AND AVN SUGGEST. AGAIN...THERE IS THE QUESTION OF WHETHER THEY ARE KEYING IN ON THE CORRECT BOUNDARIES. I LIKE THE IDEA OF WASHING THE BOUNDARY OUT ACROSS OUR SOUTHERN ZONES ON SAT...WITH THE REMNANTS DRIFTING N ON SAT NIGHT. IN ANY EVENT...THERE SHOULD BE A FAIR AMOUNT OF SUN ON SAT. THE PRELIMINARY ZONE FORECASTS WILL BE SENT TO BGM BY 315...AND THE ZONE FORECASTS WILL GO AT 400. .PHI...DENSE FOG ADVISORY EARLY THIS MORNING FOR THE NJ COUNTIES OF MONMOUTH...BURLINGTON...OCEAN... ATLANTIC...CUMBERLAND AND CAPE MAY... THE DE COUNTIES OF KENT AND SUSSEX... THE MD COUNTIES OF QUEEN ANNE/S...TALBOT AND CAROLINE. IOVINO NNNN ------------------------------------------------------------------------ FPUS3 KPIT 290625 SFDPIT STATE FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 224 AM EDT FRI MAY 29 1998 THANKS MIKE FOR SHADOW ZONES!!!! THIS AFTERNOON LOOKS REAL INTERESTING. CAPES OF ABOUT 1500 J/KG OR GREATER AND LI AROUND 5 TO 6. COULD BE SOME STRONG STORMS. A FRONT IS FORECAST TO PUSH THROUGH FROM THE NORTHWEST TODAY. THIS SHOULD ADD TO THE LIFT AND HELP INITIATE THUNDERSTORM DEVELOPMENT. SHOWERS AND THUNDERSTORMS SHOULD CONTINUE THROUGH TONIGHT ENDING FROM NORTHWEST TO SOUTHEAST BY SATURDAY AFTERNOON. MOS TEMPS LOOK PRETTY GOOD SO NO CHANGES IN THAT DEPARTMENT. CAT .PIT...NONE NNNN