000 FXUS61 KPHI 080128 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 828 PM EST SAT NOV 7 2009 .SYNOPSIS... A WEAK TROUGH WILL CROSS THE AREA OVERNIGHT. OTHERWISE, HIGH PRESSURE OFF THE NORTHERN MID ATLANTIC COAST WILL BE THE MAIN WEATHER INFLUENCE INTO MONDAY. A COLD FRONT WILL APPROACH THE AREA MONDAY NIGHT AND MOVE INTO THE AREA ON TUESDAY. HIGH PRESSURE FOLLOW FOR THE MID TO LATE WORK WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... SKIES ARE CLEAR ACROSS OUR CWA AND IN SPITE OF STRONGER WINDS ALOFT, THEY HAVE NEARLY DECOUPLED. WE ARE SEEING SOME SC AND AC DEVELOP ACROSS UPSTATE AND WESTERN NY, BUT THE CURRENT FORECAST WINDS AND LATEST MODEL GUIDANCE SHOWING NVA AFTER ABT 03Z SHOULD HELP FIGHT THE CLOUDS TRYING TO ENTER OUR CWA. SO WHILE CONFIDENCE IS WEAKER ALONG OUR BORDERS WITH BGM AND OKX, WE HAVE TRENDED TEMPERATURES, CLOUDS AND WIND DOWNWARD AS PER CURRENT OBS AND THE SLIGHTLY MORE OPTIMISTIC 18Z MODEL DATA. THEREFORE, WE ARE STILL EXPECTING A DRY AND MILDER NIGHT THAN LAST NIGHT UNDER, PERHAPS, SOME DEVELOPING CLOUDS /NOT A GREAT DEAL, AND PERHAPS A BIT MORE WAY NORTH/. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... AFTER THE SHORT WAVE MOVES THROUGH, THE MID LEVEL RIDGE WILL BUILD INTO MONDAY MORNING. SURFACE HIGH PRESSURE WILL ANCHOR OFF THE NORTHERN MID ATLANTIC SEABOARD IN RESPONSE. THERE MAY BE A BIT OF WARM AIR ADVECTION CLOUDINESS ALOFT FROM TIME TO TIME, BUT EXPECT A FAIR AMOUNT OF SUNSHINE SUNDAY AND MONDAY. ALSO, SUNDAY NIGHT COULD BE A FAIR RADIATING NIGHT /THERE CERTAINLY IS A CHOICE REGARDING MINS BETWEEN THE COOLER MAV AND THE WARMER MET/. THAT SAID, THE GENERAL TENOR IS FOR DRY AND MILDER CONDITIONS THAT MAY EVENTUALLY HAVE US REFERRING TO INDIAN SUMMER. A COLD FRONT AND ASSOCIATED MID LEVEL TROUGH WILL ADVANCE MONDAY NIGHT INTO TUESDAY ONCE THE MID LEVEL RIDGE AXIS SHIFTS EAST, AND FOR NOW WE'VE GONE WITH THE TIMING OF THE 00Z ECMWF OVER THE ATYPICALLY QUICKER 12Z NAM OR THE SLOWER 12Z GFS. ALL THREE OF THESE MODELS PUSH THE MID LEVEL TROUGH FAR ENOUGH SOUTH TO KEEP MOISTURE FROM IDA OUT OF OUR AREA, AND THE FRONT WOULD NOT HAVE A LOT OF MOISTURE TO WORK WITH IF THAT ENDS UP BEING CORRECT. ON THE OTHER HAND, THERE IS SOME FRONTOGENESIS NEAR THE SURFACE AND Q-VECTOR CONVERGENCE ALOFT WITH THIS FEATURE. THERE ALSO MAY BE AN UPPER LEVEL JET PROVIDING SUPPORT, AND WE WON'T YET DISMISS THE POSSIBILITY THAT THE MODELS KEEP THE IDA MOISTURE TOO FAR SOUTH, SO WE'LL GO A BIT HIGHER WITH POPS ON TUESDAY THAN HPC IS GOING. WITH THE ADVANCING FRONT, WE'LL LEAN TOWARD THE MILDER GUIDANCE ON MONDAY NIGHT ALTHOUGH WE WON'T OVERDO IT AS THE WINDS ABOVE THE SURFACE ARE NOT PROGGED TO BE THAT STRONG. CONTINUITY WAS FOLLOWED FOR TUESDAY AS IT SEEMS CONSISTENT WITH OUR TIMING OF THE FRONT. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... LOW PRESSURE WILL MOVE ACROSS EASTERN CANADA ON TUESDAY, STAYING WELL TO OUR NORTH, BUT THE ASSOCIATED COLD FRONT WILL CROSS THE REGION ON TUESDAY NIGHT. THIS WILL THEN GIVE WAY TO A VERY STRONG AND LARGE AREA OF HIGH PRESSURE. THIS HIGH LOOKS TO PUSH EASTWARD THROUGH THE WEEK KEEPING US HIGH AND DRY THROUGH NEXT WEEKEND. THE KINK IN THIS FORECAST IS THE POSSIBILITY OF ANY MOISTURE ASSOCIATED WITH IDA IN THE GULF MAKING ITS WAY UP NORTH. THE GFS TAKES THE REMNANT SYSTEM AND THEN MOVES IT UP THROUGH THE CAROLINAS AND OFF THE MIDDLE ATLANTIC COAST. THIS SCENARIO WOULD BRING SOME DECENT RAIN TOT HE AREA THROUGH WEDNESDAY AND INTO EARLY THURSDAY. THE ECMWF HAS A DRIER SOLUTION IN WHICH THE HIGH IS STRONG ENOUGH TO SUPPRESS THE MOISTURE AND KEEP IT TO OUR SOUTH. THE CANADIAN MODEL HAS SHIFTED BACK TO LOOK MORE LIKE THE ECMWF WITH DRIER CONDITIONS. WITH THE UNCERTAINTY IN THE MODELS IT WAS THOUGHT THAT THE HIGH WILL DOMINATE AND KEEP THE REMNANT LOW FROM PUSHING NORTHWARD THUS KEEPING THE MOISTURE IN THE SOUTHEASTERN STATES. THEREFORE, WE HAVE FOLLOWED HPC GUIDANCE FOR THE EXTENDED AND HAVE KEPT THE MAJORITY OF THE FORECAST DRY. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. A WEAKENING FRONTAL BOUNDARY WILL SLIDE ACROSS OUR AREA LATE TONIGHT AND EARLY SUNDAY MORNING. WINDS SHOULD BECOME RELATIVELY LIGHT OVERNIGHT AT MOST SITES AND THEN BECOME NORTHWEST AROUND 10 KNOTS OR LESS ON SUNDAY BEFORE PERHAPS SHIFTING BACK TO THE SOUTHWEST TOWARD EVENING. THE FLOW IS FORECAST TO LIGHTER SUNDAY AND WITH MILDER AIR ARRIVING, THE SURFACE WINDS MAY TURN SOUTH OR EVEN SOUTHEAST ESPECIALLY AT KILG AND KACY DUE TO A POSSIBLE INFLUENCE FROM NEARBY WATER. OTHERWISE, SOME MID TO HIGH LEVEL CLOUDS STREAMING BY FROM TIME TO TIME THROUGH SUNDAY. ANY STRATOCUMULUS THAT FORMS TO OUR NORTHWEST WITH THE WEAKENING FRONT LATER TONIGHT SHOULD STAY NORTH OF OUR TERMINALS. IT APPEARS THE FOG POTENTIAL LATE TONIGHT AND EARLY SUNDAY MORNING IS RATHER LOW. WHILE A TOUCH OF RIVER FOG IS POSSIBLE AT KRDG, CONFIDENCE IS NOT HIGH IT ACTUALLY MAKES IT ONTO THE AIRFIELD /IF IT DOES INDEED DEVELOP/, THEREFORE IT WAS LEFT OUT AT THIS TIME. OVERALL, VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. OUTLOOK... HIGH PRESSURE IS FORECAST TO MEANDER NEARBY SUNDAY NIGHT THROUGH MONDAY NIGHT. A COLD FRONT IS THEN FORECAST TO MOVE THROUGH LATE TUESDAY. THIS SHOULD BRING SOME SHOWERS TO THE AREA ALONG WITH SOME LOWERED CEILINGS, HOWEVER THERE IS UNCERTAINTY ON HOW MUCH MOISTURE GETS PULLED NORTHWARD AHEAD OF THIS FRONT. A POSSIBLE GUSTY NORTHWESTERLY WIND MAY OCCUR TUESDAY NIGHT AND WEDNESDAY PRIOR TO HIGH PRESSURE GETTING CLOSER INTO THURSDAY. && .MARINE... HIGH PRESSURE WILL MEANDER NEAR THE AREA THROUGH MONDAY NIGHT, BRING A MORE SOUTHERLY FLOW TO OUR WATERS. ON THE BACKSIDE OF THE SURFACE HIGH, THE WINDS ABOVE THE SURFACE ARE FORECAST TO STRENGTHEN SOME RELATED TO A LOW-LEVEL JET. AS A RESULT OF THIS JET AND SOME VERTICAL MIXING, SEAS HAVE RISEN TO 5 FT AT BUOY 44009 THIS EVENING WITH WINDS GUSTING UP NEAR 25 KNOTS. WE HAVE THEREFORE RAISED A SMALL CRAFT ADVISORY FOR THE OCEAN FRONT IN EFFECT THROUGH 6AM SUNDAY MORNING. THERE WILL BE A WEAKENING FRONTAL BOUNDARY MOVING THROUGH SUNDAY, WHICH MAY ALLOW THE WINDS TO SHIFT FOR A TIME TO THE WEST. THE WINDS ARE EXPECTED TO DISSIPATE ON SUNDAY AS THE LOW-LEVEL WIND FIELD WEAKENS AND HIGH PRESSURE DOMINATES. THE NEXT FEATURE OF INTEREST WILL BE A COLD FRONT THAT IS FORECAST TO CROSS THE AREA MAINLY TUESDAY NIGHT. THE PRESSURE GRADIENT WILL TIGHTEN UP MOSTLY IN ITS WAKE AS A STRONG SURFACE HIGH BEGINS TO SLIDE EASTWARD TO THE OHIO VALLEY AND A POSSIBLE STORM IS TO OUR EAST. THIS COUPLED WITH CAA WILL COMBINE FOR MORE EFFICIENT VERTICAL MIXING AND AN INCREASED CHC OF WINDS/SEAS REACHING ADVISORY CRITERIA. THERE IS SOME UNCERTAINTY THOUGH ON THE STRENGTH OF THIS SYSTEM AS ENERGY FROM TROPICAL CYCLONE IDA, CURRENTLY IN THE NORTHWESTERN CARIBBEAN/, MAY OR MAY NOT GET INVOLVED OR IT COULD JUST GET STUCK IN THE SOUTHEASTERN UNITED STATES. BASED ON THE UNCERTAINTY, WE DID NOT GO WITH THE 12Z WAVEWATCH GUIDANCE /GFS DRIVEN/ TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS IT LOOKS OVERDONE DUE TO A STRENGTHENING SURFACE LOW TO OUR EAST AND NORTHEAST. THE AFOREMENTIONED SURFACE HIGH THEN BUILDS IN FOR THURSDAY WITH A RELAXING PRESSURE GRADIENT. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ450>455. && $$ SYNOPSIS...DELISI/GIGI NEAR TERM...DELISI SHORT TERM...DELISI LONG TERM...MEOLA AVIATION...GORSE/MEOLA MARINE...GORSE/MEOLA