Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 251515 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1015 AM EST WED FEB 25 2015 .SYNOPSIS... LOW PRESSURE OFF OF THE NORTH CAROLINA COAST WILL TRACK NORTHEASTWARD AND OUT TO SEA TODAY, THEN A COLD FRONT WILL MOVE ACROSS OUR AREA LATER TODAY. A MORE POTENT LOW PRESSURE SYSTEM ALONG THE GULF COAST TRACKS NORTHEASTWARD, WHICH THEN RACES OUT TO SEA WELL TO OUR EAST ON THURSDAY. STRONG ARCTIC HIGH PRESSURE CENTERED IN MONTANA WILL ARRIVE ALONG THE MID ATLANTIC COAST THIS COMING WEEKEND, THEN A COLD FRONT WILL CROSS OUR AREA SUNDAY NIGHT OR MONDAY. A STRONGER LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTHWEST ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WITH THE COASTAL LOW AND THE NORTHERN LOW RAPIDLY LIFTING AWAY FROM THE REGION, WE SHOULD SEE RATHER TRANQUIL WEATHER THROUGH THE DAY TIME HOURS. STILL LOOKING AT A VERY WEAK COLD FRONT MOVING IN FOLLOWED BY AN INVERTED SURFACE RIDGE SETTLING IN LATE IN THE DAY. TEMPERATURES SHOULD BE ABOUT 10 DEGREES HIGHER THAN YESTERDAY, BUT WITH BREEZY CONDITIONS, IT WON`T FEEL THAT WAY. HIGH TEMPERATURES WILL BE INTO THE 30S THROUGH MUCH OF THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... THE NEXT IN THE PARADE OF LOWS LIFTS NE ALONG THE CAROLINA COAST THROUGH THE EVENING HOURS. THOUGH THE CENTER OF THE LOW SHOULD BE WELL OUT TO SEA, A TRAILING UPPER LEVEL SHORT WAVE TROUGH CROSSING OVER THE SOUTHERN HALF OF OUR REGION COULD LEAD TO LIGHT SNOW ESPECIALLY ACROSS DELMARVA AND ACROSS FAR SOUTHERN NJ. DESPITE WHAT THE CALENDAR SAYS, MODEL SOUNDINGS REMAIN PLENTY COLD ENOUGH FOR ALL SNOW FOR THE P TYPE. AS FOR SNOW AMOUNTS, HAVE STAYED CLOSE TO THE PREVIOUS FORECAST AND WPC GUIDANCE. && .LONG TERM /THURSDAY THROUGH TUESDAY/... VERY BROAD TROUGHING ACROSS THE EASTERN HALF OF THE STATES THROUGH THE FIRST PART OF THE EXTENDED FOLLOWED BY ZONAL FLOW/WEAK RIDGING TOWARDS THE WEEKEND. A RETURN TO BROAD SCALE TROUGHING IS EXPECTED AGAIN VERY LATE IN THE PERIOD. THURSDAY...WE HAVE ISSUED A WINTER WEATHER ADVISORY FOR A LIGHT SNOW ACCUMULATION ACROSS THE EXTREME SOUTHERN DELMARVA THROUGH THE MORNING HOURS ON THURSDAY. MID-LEVEL CONSENSUS SHOWS A VERY BROAD TROUGH OVER THE REGION WITH A WEAK SOUTHERN STREAM IMPULSE SLIDING THROUGH FROM THE SOUTHWEST. AS THE WAVE MOVES TOWARDS THE EAST- NORTHEAST IT PICKS UP SPEED, WITHOUT MUCH DOWNSTREAM BLOCKING PRESENT, AND OPENS UP EVEN FURTHER ACTING MORE LIKE A STABLE WAVE THOUGH IT DOES TURN SLIGHTLY NEGATIVE. AT THE SURFACE THE CENTER OF THE LOW SHOULD REMAIN WELL TO THE SOUTH OF OUR REGION PLACING THE SOUTHERN HALF OF OUR CWA IN ITS NORTHERN FRINGE PRECIPITATION SHIELD. SOME UPPER LEVEL DYNAMICS, IN THE FORM OF A POSSIBLE COUPLED JET STREAK STRUCTURE, HAS OUR SOUTHERN ZONES WITHIN AN AREA OF BROAD SCALE LIFT. THERMALLY WE ARE COLD ENOUGH FOR ALL SNOW BUT DO NOT SEE MUCH IN THE WAY OF THERMALLY DRIVEN ENHANCEMENT, BANDING, TO HELP INCREASE OUR ACCUMULATIONS. AS WAS STATED ABOVE IN THE NEAR TERM SECTION WE STAYED CLOSE TO A WPC SNOWFALL FORECAST FOR THIS EVENT...GENERALLY A 1 TO 2 INCH EVENT WITH SOME HIGHER TOTALS POSSIBLE IN THE ADVISED AREA. IT SHOULD BE NOTED THOUGH, OUR CURRENT 90TH PERCENTILE GRAPHIC SHOWS UPWARDS OF 6 TO 8 INCHES OF SNOW POSSIBLE WITH THIS SYSTEM ACROSS THE DELMARVA. RECENT RUNS OF THE SREF, MOSTLY ITS ARW MEMBERS, HAVE GONE GANG BUSTERS WITH THE AMOUNT OF QPF, GIVEN THEIR MESOSCALE CORE WHICH COMPLETELY SKEWS THE TOTALS. USE THE SREF VERY VERY VERY CAREFULLY, OR NOT AT ALL. ELSEWHERE, NOT EXPECTING MUCH QPF TO MAKE IT FAR ENOUGH NORTH TO BE AN ISSUE. THE COLUMN REMAINS FAIRLY DRY NORTH OF THE DELMARVA AND AS THE NORTHERN STREAM MID-LEVEL TROUGH SWINGS THROUGH WE COULD SEE SOME ISOLATED TO SCATTERED SNOW SHOWERS, THOUGH THEY APPEAR TO BE PRETTY LIGHT, MOSTLY FLURRIES, WITH VERY LITTLE TO NO ACCUMULATION EXPECTED. FRIDAY - SATURDAY...HIGH PRESSURE WILL BE IN CONTROL OVER THE REGION WITH ZONALISH FLOW ALOFT TAKING SHAPE. A COUPLE MORE WELL BELOW AVERAGE TEMPERATURE DAYS ARE EXPECTED...WE END METEOROLOGICAL WINTER WITH ANOTHER CLOD SNAP. SUNDAY - MONDAY...ZONAL FLOW TURNS SHARPER AS THE BROAD TROUGH RELOADS TO OUR WEST. DEEP WEST-SOUTHWESTERLY FLOW COMMENCES AS SURFACE RIDGING DEPARTS THE COAST. TEMPERATURES BEGIN TO CLIMB CLOSER TO NORMAL. SOUTHERN STREAM SYSTEM WITH LOTS OF MOISTURE IS EXPECTED TO PASS THROUGH THE REGION DURING THIS PERIOD AND DEPENDING ON WHEN IT STARTS TO AFFECT THE AREA MIXED-PHASE PRECIPITATION WILL OCCUR. TOO EARLY FOR SPECIFICS THIS FAR OUT BUT A SNOW TO RAIN PROGRESSION LOOKS GOOD. TUESDAY...JET DYNAMICS...WAA AND POOLING MOISTURE IN THE SOUTHERN UNITED STATES FAVOR THE DEVELOPMENT A HEAVY PRECIPITATION EVENT. TOO EARLY FOR DETAILS SINCE THE SYSTEM MAY END UP SLIGHTLY WEAKER AND THEREFORE COLDER AND FURTHER EAST. ESSENTIALLY A MIXED PCPN EVENT AT THIS DISTANT OUTLOOK. CONFIDENCE: AVERAGE OR ABOVE ON AN EVENT BUT ONLY AVERAGE OR BELOW ON THE THERMAL PROFILES. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS SHOULD CONTINUE THROUGH AT LEAST 06Z. VERY LATE TONIGHT (AFTER 06Z, BUT LIKELY CLOSER TO 09Z), SNOW SHOULD BEGIN TO MOVE INTO SOUTHEASTERN PORTIONS OF THE REGION. AT THIS TIME, KPHL, KPNE, KILG, KMIV, AND KRDG HAVE A LOW CHANCE OF SEEING SNOW OVERNIGHT, WHILE KACY HAS THE HIGHEST CHANCE. EXPECT CEILINGS TO LOWER AFTER 06Z, THOUGH WILL LIKELY REMAIN IN THE VFR CATEGORY. AND WITH ANY SNOW, EXPECT TO SEE MVFR VISIBILITIES. OUTLOOK... THURSDAY...MOSTLY VFR. STEADY MVFR/IFR SNOW AROUND MIV/ACY THURSDAY MORNING. ISOLATED TO SCATTERED SNOW SHOWERS POSSIBLE THURSDAY AFTERNOON. FRIDAY - SATURDAY...VFR. SUNDAY...VFR TO START. CONDITIONS DETERIORATE LATE IN THE DAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST-SOUTHWEST. && .MARINE... WESTERLY WINDS WILL INCREASE AFTER DAYBREAK. BY MID DAY, GUSTS NEAR 25KT WILL BE POSSIBLE ON THE NORTHERN NEW JERSEY COASTAL WATERS. WITH THE INCREASING WINDS, SEAS SHOULD ALSO INCREASE, ESPECIALLY ON THE NORTHERN NEW JERSEY COASTAL WATERS. ELSEWHERE, WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA THROUGH THE DAY AND THIS EVENING. AFTER MIDNIGHT, COULD SEE WINDS INCREASE AGAIN, WITH GUSTS ABOVE 20KT POSSIBLE ON THE ATLANTIC COASTAL WATERS. OUTLOOK... THURSDAY... WINDS TURN NLY AND INCREASE TO AROUND 20 KT WITH NEAR SCA LEVELS. MODERATE FREEZING SPRAY IS ALSO POSSIBLE AS WINDS AND WAVES INCREASE THURSDAY INTO FRIDAY. FRIDAY - SATURDAY...SUB-SCA EXPECTED, THOUGH PERSISTENT NORTHEAST WINDS MAY ALLOW FOR BUILDING SEAS ACROSS OUR SOUTHERN ZONES. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST THURSDAY FOR DEZ003-004. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ450- 451. && $$ SYNOPSIS...DRAG/GORSE NEAR TERM...JOHNSON/MEOLA SHORT TERM...JOHNSON LONG TERM...HEAVENER AVIATION...HEAVENER/JOHNSON MARINE...HEAVENER/JOHNSON

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