Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 270916 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 416 AM EST TUE JAN 27 2015 .SYNOPSIS... A STRONG STORM SYSTEM ABOUT 200 MILES OFF THE NEW JERSEY COAST THIS MORNING WILL MOVE TOWARD THE GULF OF MAINE THIS AFTERNOON AND TONIGHT BEFORE REACHING THE CANADIAN MARITIMES ON WEDNESDAY. HIGH PRESSURE BUILDING IN FROM THE OHIO VALLEY WEDNESDAY WILL SETTLE OVERHEAD WEDNESDAY NIGHT. A CLIPPER SYSTEM WILL MOVE THROUGH THE REGION THURSDAY NIGHT AND FRIDAY MORNING. HIGH PRESSURE RETURNS SATURDAY BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES INTO THE EASTERN UNITED STATES SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE SIGNIFICANT LOW PRESSURE SYSTEM THAT HAS BROUGHT SEVERE WINTER WEATHER TO THE MIDDLE ATLANTIC AND NORTHEAST IS EAST OF NJ THIS MORNING AND IT CONTINUES TO DEEPEN. IT WILL MOVE UP EAST OF LONG ISLAND AND UP TOWARDS NEW ENGLAND LATER TODAY. THE STRONGEST DYNAMICS/MOISTURE AFFECTED ERN NJ OVERNIGHT WITH THE MOST SIGNIFICANT WX MOVING JUST TO OUR E. STILL SIGNIFICANT SNOW AND SOME BLOWING SNOW THIS MORNING FOR THE ERN/NE PARTS OF THE CWA. WE WILL TAKE DOWN THE BLIZZARD WARNING AND REPLACE IT WITH A WINTER STORM WARNING FOR SEVERAL HOURS INTO THE MORNING. THE PERIPHERY OF THE WARNING WILL BE FLANKED BY ADVISORIES WITH LIGHTER AMTS OF SNOW AND AREAS OF BLOWING/DRIFTING SNOW EARLY TODAY. A FEW OF THE WRN/SRN AREAS WILL BE DROPPED FROM THE ADVISORIES ISSUED EARLIER. CONDITIONS IMPROVE THIS AFTERNOON...BUT GUSTY WINDS WILL CONTINUE INTO THE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... DEEP LOW PRESSURE WILL CONTINUE TO PULL AWAY TO THE NORTHEAST AS HIGH PRESSURE BEGINS TO BUILD OVER THE AREA. THE ONLY MENTION OF PRECIP WILL BE SOME LEFTOVER SNOW SHOWERS THIS EVENING ACROSS THE SRN POCONOS AND CLOSER TO NYC AREA. SKIES WILL BECOME PARTLY CLOUDY TO CLR FROM THE SW TO NE AS THE NIGHT PROGRESSES. LOWS TONIGHT WILL BE IN THE TEENS AND LOW 20S OVER MOST AREAS WITH A FEW SINGLE DIGIT READINGS OVER THE SRN POCONOS. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... THE COASTAL LOW WILL STEADILY WEAKEN ON WEDNESDAY AS IT LIFTS NORTHEASTWARD THROUGH THE CANADIAN MARITIMES. NORTH-NORTHWESTERLY FLOW ON THE BACKSIDE OF THE TROUGH WILL GRADUALLY WEAKEN THROUGHOUT THE DAY AS HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY. WEDNESDAY WILL BE 5-10F DEGREES BELOW NORMAL. HOWEVER, DID LEAN ON THE WARMER SIDE OF GUIDANCE FOR MAX TEMPS UNDER FULL SUNSHINE AND ADIABATIC WARMING FROM A DOWNSLOPING COMPONENT TO THE WINDS AS WELL AS LARGE SCALE SUBSIDENCE IN WAKE OF THE EXITING TROUGH. RADIATIONAL COOLING SHOULD BE STRONG WITH CLEAR SKIES AND CALM WINDS OVERNIGHT AS THE CENTER OF HIGH PRESSURE SHIFTS DIRECTLY OVERHEAD. GIVEN HOW DRY THE AIRMASS IS, THERE IS THE POTENTIAL FOR TEMPS TO BOTTOM OUT IN THE TEENS FOR THE I-95 URBAN CORRIDOR, ALONG THE COAST AND IN THE DELMARVA AND SINGLE DIGITS ELSEWHERE. MIN TEMP FORECAST WAS A BLEND BETWEEN PREVIOUS FORECAST (WHICH WAS THE COLDER THAN ANY 00Z GUIDANCE) AND THE 00Z NAM. AN ALBERTA CLIPPER IS FORECAST TO TRACK EASTWARD ACROSS THE UPPER MIDWEST/GREAT LAKES ON THURSDAY BEFORE MOVING THROUGH THE NORTHEAST STATES ON FRIDAY. ISENTROPIC LIFT AHEAD OF THE ATTENDANT COLD FRONT AND DPVA WITH THE UPPER SHORTWAVE TROUGH WILL SPREAD INTO NORTHEASTERN PA LATE IN DAY THURSDAY AND THE REMAINDER OF THE CWA THURSDAY NIGHT. A PERIOD OF LIGHT SNOW IS LIKELY DURING THIS TIME WITH THE HIGHEST POPS OVER EASTERN PA AND NORTHERN NJ. THIS SYSTEM WILL HAVE A BIT MORE MOISTURE (PWAT APPROACH 0.6 INCHES) TO WORK WITH THAN WHAT TYPICALLY ACCOMPANIES CLIPPERS AS IT IS ABLE TO TAP INTO LIMITED GULF OF MEXICO MOISTURE. GIVEN THE PROGRESSIVE NATURE OF THE LOW IS AND THE FACT THAT IT IS NOT FORECAST TO STRENGTHEN UNTIL IT REACHES THE GULF OF MAINE, SNOWFALL AMOUNTS SHOULD BE LIGHT: 1-3 INCHES IN THE POCONOS AND EXTREME NW NJ, LESS THAN AN INCH FARTHER SOUTH AND EAST. STRONG CAA BEHIND THE COLD FRONT ON FRIDAY. MAX TEMPS IN THE 30S ARE FORECAST TO OCCUR IN THE AM WITH TEMPS FALLING THROUGHOUT THE AFTERNOON. BRISK NW WINDS HAVE THE POTENTIAL TO GUST 30-40 MPH ASSUMING DEEP MIXING IS REALIZED ON LAND. ADDITIONAL SNOW SHOWERS ARE POSSIBLE IN THE POCONOS. DAYS 4.5-7 OF THE FORECAST WAS BASED ON THE 05Z/27 WPC ELEMENTS OF TT/TD/WIND/SKY/POP. WE ADJUSTED THE WPC TEMPS MUCH HIGHER SUN NIGHT AND A BIT HIGHER MONDAY PER NEW 00Z/27 MODE GUIDANCE SUGGESTING LOW PRESSURE AND PRECIPITATION IN THIS TIME FRAME. FRI NIGHT...VERY COLD WITH WIND CHILL ADVISORY POTENTIAL. NW FLOW BEHIND THE DEPARTING AREA OF LOW PRESSURE SHOULD STILL HAVE GUSTY WINDS WITH IT THROUGH THE NIGHT. SATURDAY...FAIR AND VERY COLD. AVERAGE TEMPS ABOUT 15 DEGREES BELOW NORMAL. SUNDAY...MODERATING WITH INCREASING CLOUDS DURING THE DAY AND PCPN OF SOME SORT EXPECTED AT NIGHT. HIGHLY VARIABLE SET OF SOLUTIONS AND CONFIDENCE ON TEMPS/PTYPE IS WELL BELOW AVERAGE. MONDAY...MAYBE SOME LEFT OVER PCPN, ESPECIALLY DURING THE MORNING THEN DRYING OUT AND TURNING COLDER. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WRAPAROUND SNOW FROM THE COASTAL STORM CONTINUES TO EXPAND TO THE SOUTH AND WEST ACROSS THE AREA EARLY THIS MORNING. THE TERMINALS ARE LOCATED ON THE WESTERN PERIPHERY, WHERE LIFT IS WEAKER AND SNOW IS LIGHTER. HAVE HIGHLIGHTED A 3-4 HOUR TEMPO GROUP EARLY THIS MORNING FOR IFR VSBYS AT TTN/PNE/PHL/ACY AND MVFR FARTHER SOUTH AND WEST. THIS SHIELD OF SNOW MAY LINGER OVER THE TERMINALS THROUGH ABOUT 18Z BUT VSBYS SHOULD GRADUALLY IMPROVE AFTER 15Z AS THE INTENSITY OF THE SNOW TAPERS OFF. N-NW WINDS 15-20 KT WILL GUST UP TO 25 KT TODAY. BLSN MAY REDUCE VSBYS LOCALLY AT THE TERMINALS BUT WAS NOT AS PESSIMISTIC WITH THE VSBYS SINCE THERE IS ONLY A FRACTION OF SNOW ON THE GROUND AS PREVIOUSLY ANTICIPATED. VFR LATE THIS AFTN AND TONIGHT. WINDS RELAX A BIT OVERNIGHT. OUTLOOK... WEDNESDAY AND WEDNESDAY NIGHT...PRIMARILY VFR. NW WINDS 10-15 KT IN THE DAY, BECOMING CALM AT NIGHT. THURSDAY INTO FRIDAY MORNING...VFR TO FOR MUCH OF THURSDAY. LIGHT SNOW WILL LIKELY SPREAD INTO THE AREA FROM WEST TO EAST THURSDAY NIGHT BUT MAY REACH ABE/RDG BY LATE AFTERNOON. MVFR/IFR RESTRICTIONS POSSIBLE WITH THE SNOW. HIGHEST CONFIDENCE IS AT NORTHERN TERMINALS. FRIDAY AFTERNOON...VFR WITH BLUSTERY NW WIND GUSTING TO 30 KT. FRI NIGHT...VFR. GUSTY NW WINDS. SATURDAY...VFR. && .MARINE... STORM WARNINGS CHANGED TO GALE WARNINGS FOR NJ WATERS. DEEP LOW PRESSURE EAST OF THE WATERS WILL CONTINUE TO MOVE NORTHEAST TODAY. STRONG WINDS WILL CONTINUE TODAY WITH GALE GUSTS EXPECTED AT LEAST THE FIRST PART OF TODAY. WINDS WILL PROBABLY DROP BACK BELOW GALE STRENGTH LATER...BUT THE DAY SHIFT CAN MAKE THAT CALL LATER. SIGNIFICANT SEAS WILL CONTINUE TODAY THEN SUBSIDE TONIGHT. OUTLOOK... WEDNESDAY...SCA LIKELY WITH FREEZING SPRAY. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...NO MARINE HEADLINES ARE ANTICIPATED. SOME FREEZING SPRAY POSSIBLE WEDNESDAY NIGHT. FRIDAY- NEAR GALE-FORCE GUSTS BEHIND A CLIPPER SYSTEM. FRI NIGHT: POSSIBLE LEFTOVER NW GALE FORCE WIND GUSTS. SATURDAY...SCA CONDITIONS POSSIBLE. && .TIDES/COASTAL FLOODING... THE JUST-PASSED HIGH TIDE ALONG THE NJ/DEL SHORE PRODUCED MINOR TIDAL FLOODING AND SOME MAY BE ONGOING ACROSS LOWER DEL BAY. WE NO LONGER EXPECT ANY SERIOUS TIDAL FLOODING TO OCCUR AND THE COASTAL FLOOD WARNING WILL BE DROPPED. THE SUBSEQUENT TIDES WILL LIKELY NOT BE SIGNIFICANT...SINE WINDS WILL BECOME OFFSHORE TODAY AND REMAIN THAT WAY FOR TONIGHT AND TUE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR PAZ055-062- 071-103>106. NJ...WINTER STORM WARNING UNTIL 3 PM EST THIS AFTERNOON FOR NJZ001- 007>010-012>015-020-025-026. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NJZ018-019- 027. DE...NONE. MD...NONE. MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ430-431- 450>455. && $$ SYNOPSIS...KLEIN NEAR TERM...O`HARA SHORT TERM...O`HARA LONG TERM...DRAG/KLEIN AVIATION...DRAG/KLEIN MARINE...DRAG/KLEIN TIDES/COASTAL FLOODING...O`HARA

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