FXUS61 KPHI 202209 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 509 PM EST TUE JAN 20 2009 .SYNOPSIS... LOW PRESSURE OFF THE MID-ATLANTIC COAST THIS EVENING WILL MOVE NORTHEAST AND OUT TO SEA TONIGHT. HIGH PRESSURE WILL THEN BUILD IN OVER THE AREA FOR THE REST OF THE WEEK. A COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT OR EARLY SATURDAY FOLLOW BY MORE ARCTIC HIGH PRESSURE FOR THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE LATEST SURFACE ANALYSIS SHOWS LOW PRESSURE WELL OFF THE MID- ATLANTIC COAST AND IT APPEARS THAT EVEN THE SE CORNER OF OUR FCST AREA...I.E. THE DELAWARE COAST...WILL LIKELY AVOID ANY EFFECTS FROM THIS SYSTEM. FOR THE NW PART OF THE AREA...STCU CLOUDS ARE STREAMING SWD ACROSS ERN PA AND NW NJ IN LOW-LVL COLD ADVCTN. THESE COULD BRING SOME SCT FLURRIES TO THE POCONOS TONIGHT. OTRW... A MAINLY CLEAR AND CHILLY NIGHT IS EXPECTED WITH TEMPERATURES DROPPING THRU THE 20S AND INTO THE TEENS MOST AREAS. THE RELATIVELY FRESH SNOW COVER MAY ALLOW MIN TEMPS TO REACH THE SINGLE DIGITS IN AREAS N AND W OF PHILA. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... THE WX WILL REMAIN BENIGN THRU THE SHORT TERM PERIOD AS A LARGE AREA OF HIGH PRES CENTERED OVE THE SERN US MOVES SLOWLY EWD ACROSS THE FCST AREA. FORTUNATELY THE AMS ASSOCD WITH THIS HIGH IS NOT AS COLD AS LAST WEEK SO WED MAX TEMPS WILL BE WELL BELOW NORMAL BUT SHOULD BE EASILY TOLERATED WITH SUNSHINE. AS THE HIGH PRES RIDGE MOVES OFFSHORE ON THU A SWLY FLOW WILL DEVELOP BRING MILDER AIR INTO THE REGION. MAX TEMPS ON THU SHOULD BE SOMEWHERE NEAR NORMAL WITH PARTLY TO MOSTLY SUNNY CONDS CONTG. ALSO DURG THIS TIME...THE LARGE-SCALE UPPER TROF IS FCST TO MOVE OFF THE EAST COAST AND THE FLOW ALOFT BECOMES MORE ZONAL...BUT RETAINS A NWLY COMP WHICH FAVORS GENLY DRY CONDS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... THE SW FLOW AND THE TREND TWDS MILDER CONDS WILL CONT ON FRI. MAX TEMPS ON FRI ARE EXPECTED TO BE ABOVE NORMAL. LOW-LVL MSTR/DEWPTS WILL ALSO INCREASE SMWHT BUT THE HIGH PRES RIDGE ACROSS THE SERN US SEEMS TO BLOCK MUCH OF THE MOISTURE. A STRONG COLD FRONT IS FCST TO CROSS THE AREA FRI OVERNIGHT OR EARLY SAT. MODELS DIFF SMWHT ON THE TIMING BUT THE HPC PROG HAS THE FRONT OFF THE NJ COAST AT 12Z SAT SO WE WENT WITH THAT. IT APPEARS THAT THERE WILL NOT BE MUCH MSTR AVAILABLE TO INTERACT WITH THE FRONT SO WE INCLUDED JUST A SLIGHT CHC FOR PRECIP IN THE GRIDS FOR FRI NIGHT. THEN THE CANADIAN HIGH BUILDS IN BEHIND THE FRONT FOR THE WEEKEND. THIS HIGH DOES NOT SEEM TO BE QUITE AS STRONG AS THE ONE LAST WEEK AND THE FCST 850MB TEMPS ARE NOT AS COLD...BUT MAX/MIN TEMPS FOR THE WEEKEND SHOULD STILL BE WELL BELOW NORMAL. THE FLOW ALOFT DURG THE WEEKEND IS FCST TO BE ZONAL WITH NO SGFNT SHRWVS EXPECTED. FOR EARLY NEXT WEEK THE FCST BECOMES MORE CLOUDY...LITERALLY AND FIGURATIVELY. A SWLY FLOW DEVELOPS ALOFT WITH INCRG MSTR SPRDG OVER THE REGION. GUIDANCED INDCS CHC POPS FOR MON AND TUE AS A FRONTAL BNDRY IS FCST TO SET UP TO OUR SOUTH WITH A WAVE OF LOW PRES PSBLY DEVELOPING ALONG IT. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. OTHER THAN SOME CIRRUS, THE SKY OVER OUR REGION WAS MAINLY CLEAR AT MID AFTERNOON. THERE WAS A NORTHERLY WIND AT 10 TO 15 KNOTS, WITH GUSTS UP AROUND 20 KNOTS. HIGH PRESSURE IS FORECAST TO BEGIN NOSING UP FROM THE SOUTHWEST. AS A RESULT, VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. SOME STRATOCUMULUS WAS FILTERING DOWN FROM NEW YORK STATE AND NORTHERN PENNSYLVANIA THIS AFTERNOON. THE CLOUDS SHOULD AFFECT OUR REGION TONIGHT, WITH OCCASIONAL CEILINGS IN THE 3500 TO 4500 FOOT RANGE. THE NORTHERLY WIND IS EXPECTED TO DIE DOWN A SLIGHT BIT FOR TONIGHT AND WEDNESDAY MORNING. OUTLOOK... HIGH PRESSURE SHOULD CONTINUE TO INFLUENCE OUR REGION FROM WEDNESDAY AFTERNOON INTO FRIDAY WITH VFR CONDITIONS LIKELY. A COLD FRONT FROM THE NORTHWEST IS FORECAST TO ARRIVE ON FRIDAY NIGHT. THE FRONT SHOULD HAVE ONLY A LIMITED AMOUNT OF MOISTURE ASSOCIATED WITH IT, SO CONDITIONS COULD REMAIN MAINLY IN THE VFR RANGE. HIGH PRESSURE IS ANTICIPATED TO FOLLOW THE COLD FRONT FOR THE COMING WEEKEND. && .MARINE... LOW PRESSURE, LOCATED OFF THE NORTH CAROLINA COAST THIS AFTERNOON, WILL MOVE QUICKLY TO THE NORTHEAST AND OUT TO SEA TONIGHT. HIGH PRESSURE IS FORECAST TO NOSE UP FROM THE SOUTHWEST FOR WEDNESDAY AND THURSDAY. THE GRADIENT BETWEEN THE LOW MOVING OUT TO SEA AND THE HIGH BUILDING UP FROM THE SOUTHWEST MAY RESULT IN SOME 25 TO 30 KNOT WIND GUSTS IN OUR MARINE AREA THROUGH MID MORNING ON WEDNESDAY. AS A RESULT, WE HAVE MAINTAINED THE SMALL CRAFT ADVISORY UNTIL 1000 AM ON WEDNESDAY. WAVES ON OUR OCEAN WATERS WILL LIKELY REMAIN IN THE 3 TO 6 FOOT RANGE UNTIL THE WIND BEGINS TO SUBSIDE SLOWLY LATE ON WEDNESDAY MORNING. RELATIVELY TRANQUIL CONDITIONS ARE EXPECTED FROM WEDNESDAY AFTERNOON INTO FRIDAY, WITH A WEST TO SOUTHWEST WIND AT 10 TO 20 KNOTS. A COLD FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST ON FRIDAY AND IT SHOULD REACH THE COASTAL WATERS OF NEW JERSEY AND DELAWARE LATE ON FRIDAY NIGHT. HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR THE WEEKEND. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ430-431- 450>455. && $$ SYNOPSIS...AMC NEAR TERM...AMC SHORT TERM...AMC LONG TERM...AMC AVIATION...IOVINO MARINE...IOVINO