Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 271844 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 144 PM EST TUE JAN 27 2015 .SYNOPSIS... THE STRONG STORM SYSTEM RESPONSIBLE FOR OUR RECENT SNOW 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/... HAVE UPDATED THE GRIDS/ZONES TO CANCEL THE ADVISORY AND WARNING AS THE DEFORMATION ZONE HAS SNOWED ITSELF OUT. LIGHT SNOW CONTINUES OVER A GOOD PORTION OF OUR FORECAST AREA NORTH OF PHILA. SKIES WILL REMAIN CLOUDY THROUGHOUT MOST OF THE DAY...BUT THERE COULD BE SOME BRIGHTER SPOTS TOWARD BERKS COUNTY. HIGH TEMPS AROUND 20 FAR NORTH, UPPER 20S TO AROUND 30 IN THE PHL METRO AREA...AND MID 30S FAR SOUTH. WE CONTINUE TO ISSUE UPDATED PUBLIC INFORMATION STATEMENT CONTAINING THE LATEST SNOWFALL REPORTS. WE THANK ALL THOSE WHO HAVE GONE OUT AND MEASURED THEIR SNOW AND REPORTED TO US. IT REALLY HELPS OUR FORECAST PROCESS. && .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 /19Z TUESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. CONDITIONS HAVE GRADUALLY IMPROVED TO VFR AND SKIES WILL TRANSITION TO BROKEN AND SCATTERED THROUGHOUT THE REMAINDER OF THE AFTERNOON. ANY REMAINING MVFR CEILINGS WILL TRANSITION TO VFR BY 20Z. NORTHWEST WIND GUSTS AROUND 20 KNOTS WILL CONTINUE AT ALL TAF SITES. FOR TONIGHT THERE IS POTENTIAL FOR SOME LOW CLOUDS AROUND 2,000 FEET TO FORM. HOWEVER WITH CONTINUED NORTHWEST WINDS OVER 10 KNOTS THERE IS LITTLE TO MODERATE CONFIDENCE THIS WILL OCCUR. WEDNESDAY WILL BE A VFR DAY WITH NORTHWEST GUSTS AGAIN AROUND 20 KNOTS. SOME HIGHER GUSTS ARE POSSIBLE IN THE AFTERNOON. GUSTS WILL AGAIN DECREASE AFTER SUNSET. 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 OVERNIGHT HIGH TIDE ALONG THE NJ/DEL SHORE AND DEL BAY PRODUCED MINOR TIDAL FLOODING, BUT NOTHING TOO SERIOUS. WITH A WELL- ESTABLISHED NORTHWEST FLOW OVER THE REGION, NO ADDITIONAL TIDAL ISSUES ARE EXPECTED WITH SUBSEQUENT HIGH TIDE CYCLES. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ430-431- 450>455. && $$ SYNOPSIS...KLEIN NEAR TERM...MIKETTA SHORT TERM...O`HARA LONG TERM...DRAG/KLEIN AVIATION...DRAG/FRANCK/GAINES/KLEIN MARINE...DRAG/KLEIN TIDES/COASTAL FLOODING...

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