Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPHI 272217 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 517 PM EST FRI FEB 27 2015 .SYNOPSIS... STRONG AND EXTENSIVE HIGH PRESSURE CENTERED OVER THE MIDWEST ARRIVES ALONG THE MID ATLANTIC COAST THIS WEEKEND. A WEAK WARM FRONT LIFTS THROUGH OUR AREA LATE SUNDAY NIGHT FOLLOWED QUICKLY BY A COLD FRONT MONDAY MORNING. COLD HIGH PRESSURE RETURNS MONDAY NIGHT. LOW PRESSURE IN THE CENTRAL PLAINS TUESDAY MOVES TO OUR NORTH WEDNESDAY. ITS COLD FRONT PASSES THROUGH OUR AREA WEDNESDAY NIGHT, POSSIBLY WITH AN ATTENDANT WAVE OF LOW PRESSURE. EXPANSIVE HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY FILTERS INTO OUR AREA LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... HIGH PRESSURE WILL GRADUALLY BUILD EASTWARD FROM THE OHIO VALLEY THIS EVENING. THIS WILL ALLOW FOR MOSTLY CLEAR SKIES TONIGHT AS CLOUDS ALONG THE COAST MOVE OFFSHORE. CONDITIONS WILL BE FAVORABLE FOR RADIATIONAL COOLING AS WELL WITH NORTHWEST WINDS UNDER 10 MPH. TEMPERATURES INCORPORATE THE GFS MODELED TWO METER TEMPERATURES WHICH SEEM TO HAVE BETTER HANDLED THE SNOWCOVER AND THE MET/MAV GUIDANCE SETS. SINGLE DIGITS FOR MOST OUTSIDE OF PHILADELPHIA TONIGHT. CLIMATE SECTION HAS MORE ON THE THREAT FOR ANY RECORDS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... SATURDAY LOOKS LIKE A PLEASANT BUT COLD DAY ACROSS THE REGION. NORTHWEST WINDS WILL CONTINUE TO BE UNDER 10 MPH, PERHAPS SHIFTING TO MORE WESTERLY LATE. WITH THE HIGH PRESSURE IN PLACE ONLY SOME HIGH CIRRUS IS EXPECTED WITH SOME ADVECTING MID AND UPPER LEVEL MOISTURE IN THE AFTERNOON. THE MET AND MAV GUIDANCE SETS HAVE BEEN TO COOL WITH HIGHS IN RECENT SUNNY DAYS, WENT A COUPLE DEGREES WARMER WITH HIGHS DUE TO RECENT TRENDS. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... **WINTERY WX EVENTS SLATED FOR SUNDAY NIGHT AND TUESDAY NIGHT AT LEAST IN EASTERN PA AND NW NJ** 500MB: A SHORT WAVE IN SOUTH CENTRAL CANADA SATURDAY NIGHT MOVES TO NEW ENGLAND MONDAY; THEN A PARTIAL PHASING OF SOUTHERN AND NORTHERN STREAM SHORT WAVES OCCURS MONDAY NIGHT AND TUESDAY IN THE PLAINS STATES. THAT TROUGH MOVES TO QUEBEC WEDNESDAY WHILE A TRAILING SHORT WAVE FOLLOWS TO THE EAST COAST THURSDAY. BROAD NORTHWESTERLY FLOW FOLLOWS NEXT FRIDAY ACROSS EASTERN NORTH AMERICA. TEMPERATURES: WE`RE IN THE PROCESS OF CLOSING OUT THE TOP 5 OR 6 COLDEST FEBRUARY IN LONG TERM CLIMAT HISTORY DATING BACK TO THE 1870S; THE CALENDAR DAY AVERAGE TEMPERATURE SUNDAY SHOULD BE CLOSE TO 15 DEGREES BELOW NORMAL WITH A SMALL CHANCE OF RECORD LOWS SUNDAY MORNING IN THE RADIATIONAL COOLING COUNTRYSIDE NEAR ATLANTIC CITY AND MAYBE NEAR TRENTON, DEPENDENT ON WHETHER THICK CLOUD COVER ARRIVES AT 06Z OR 9Z. A LATER ARRIVAL PERMITS A BETTER CHC OF RECORDS. MONDAY SHOULD BE CLOSE TO OR SLIGHTLY BELOW NORMAL BUT IT COOLS AGAIN ON TUESDAY TO ABOUT 10 DEGREES BELOW NORMAL. WEDNESDAY IS PROBABLY THE WARMEST DAY OF THE WORKWEEK, WITH POTENTIAL 50S TO LOWER 60S I-95 SEWD AND CALENDAR DAY AVERAGE TEMPS SEVERAL DEGREES ABOVE NORMAL. THEREAFTER, THE 12Z/27 ECMWF ECMWF OPERATIONAL RUN HAS COME INTO GREATER AGREEMENT WITH THE GFS ON ANOTHER COLD SHOT AT THE END OF NEXT WEEK, DAYTIME MAX TEMP COLD BIAS NOTWITHSTANDING. TEMPS MAY RUN 5 DEGREES OR MORE BELOW NORMAL BOTH THURSDAY AND FRIDAY. FORECAST BASIS: UNLESS OTHERWISE NOTED, 50 50 BLEND 12Z/27 GFS/NAM MOS GUIDANCE SATURDAY NIGHT-SUNDAY NIGHT, 12Z/27 MEX MOS MONDAY AND MONDAY NIGHT THEN THE 15Z/27 WPC GRIDDED ELEMENTS OF MAX/MIN TEMP, 12 HOUR POP, 6 HOUR DEWPOINT-SKY-WIND FROM TUESDAY- NEXT FRIDAY. THE DAILIES... SATURDAY NIGHT...CLEAR TO PARTLY CLOUDY (CIRRUS EARLY EVENING) WITH STRONG COUNTRYSIDE RADIATIONAL COOLING AND NEAR RECORD LOWS POSSIBLE KTTN AND KACY, THEN CLOUDING UP RAPIDLY TOWARD SUNRISE. LIGHT WIND. RECORDS DEPENDENT ON TIMING OF THE ARRIVAL OF THICK CLOUD COVER. THE WARMER NAM TEMPS WERE NOT FACTORED INTO THIS SATURDAY NIGHT FORECAST AT ALL. GFS 2M TEMPS ARE A SIGNIFICANT INDICATOR OF RADIATIONAL COOLING. ADVISORY EVENT HIGHLY PROBABLY SUNDAY AFTERNOON AND NIGHT. SUNDAY AND SUNDAY NIGHT...CLOUDY: PRECIPITATION DEVELOPS MIDDAY OR SUNDAY AFTERNOON. PHL SEWD A TINY BIT OF SNOW CHANGING TO SLEET AND FREEZING RAIN. MOSTLY LIGHT SOUTH WIND. MEANWHILE SNOW ACCUMULATES NW OF I-95 AND WHILE WE JUST DON`T KNOW HOW MUCH (2 TO 6"--HEAVIEST SOMEWHERE N OF I-78), WE DO SEE THE NAM THERMAL PROFILES ARE SUBFREEZING FOR QUITE A BIT OF TIME SO THAT EVEN IF A WARM ABOVE FREEZING NOSE POKES NORTHWARD, WE ARE THEN LOOKING AT ICE. LIGHT WIND. MOST OF THE SNOW ACCUMULATION IS PROBABLY 5 PM TO MIDNIGHT. THERE IS CONCERN THAT THIS EVENT WILL END UP MOSTLY SNOW AND LESS FREEZING RAIN. HOWEVER...SE OF I95 WE SHOULD WARM ENOUGH TO EXPERIENCE A BIT OF NON FREEZING RAIN AFTER 08Z MONDAY. ONE CAUSE OF THE PCPN IS AN INSTABILITY BURST HEADED FOR THE DELMARVA. MONDAY...ANY LEFTOVER SHOWERS AT SUNRISE QUICKLY END ALONG THE COAST, THEN AT LEAST PARTIAL CLEARING WITH NW WINDS GUSTING AROUND 35 MPH DURING THE AFTERNOON WITH STRONG CAA. MONDAY NIGHT...CLEAR RADIATIONAL COOLING FOLLOWED BY INCREASING HIGH CLOUDS AFTER MIDNIGHT. LIGHT WIND. TUESDAY...THICKENING CLOUDS. CHANCE OF SNOW LATE IN THE DAY? LIGHT SOUTH WIND. TUESDAY NIGHT...ANY MIXED WINTRY PCPN QUICKLY CHANGES TO RAIN I-95 SEWD BUT NW OF I-95 SNOW CHANGES TO ICE AND THEN PROBABLY RAIN. TIMING UNCERTAIN. LIGHT SOUTH WIND SHIFT SW LATE. ANOTHER STRONG INSTABILITY BURST THAT NOSES TO THE DELMARVA. WEDNESDAY...CONSIDERABLE CLOUDINESS AND MILDER. HOW MILD IS A BIT UNCERTAIN BUT POTENTIALLY FLIRTING WITH 60 PHL SEWD?, COOLER TO THE NORTH AND WARMTH DEPENDENT IN PART ON SOUTHWEST FLOW MIXING. SW WIND SHIFTS TO NW. WEDNESDAY NIGHT-THURSDAY MORNING...THE CFP TO BE ACCOMPANIED BY A PERIOD OF SHOWERS. IF A WAVE FORMS ON THE FRONT THEN POSSIBLY ENDING AS A TOUCH OF SNOW? THURSDAY AFTERNOON...TURNING MUCH COLDER. NW WIND GUSTY 25-30 MPH. FRIDAY...FAIR AND COLD. W-NW WIND GUST 20 MPH. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS THROUGH THE TAF PERIOD. SOME SCATTERED CLOUDS THIS EVENING AROUND 5,000 FEET SHOULD CLEAR OUT EARLY. CIRRUS ABOVE 10,000 FEET SHOULD MOVE IN OVERNIGHT. NORTHWESTERLY WINDS FROM 320- 350 DEGREES AS WELL, TOP WINDS AROUND 10 KNOTS THIS AFTERNOON WITH ISOLATED WIND GUSTS BEFORE 23Z. WIND COULD SHIFT MORE WESTERLY WITH SLIGHTLY LOWERING CIRRUS IN THE AFTERNOON ON SATURDAY. OUTLOOK... SATURDAY NIGHT - SUNDAY MORNING...VFR CLEAR TO START WITH LIGHT WIND THEN RAPIDLY LOWERING CIGS TO NEAR 5000 FT FROM WEST TO EAST IN THE 09Z-17Z TIME FRAME. SUNDAY AFTERNOON AND NIGHT...MVFR OR IFR CONDS IN SNOW CHANGING TO RAIN VCNTY KPHL SOUTH AND EAST AND SNOW CHANGING TO ICE KRDG/KABE/KTTN/KPNE. LIGHT WIND. MONDAY...BECOMING VFR WITH A GUSTY NW WIND 30 TO POSSIBLY 35 KT IN THE AFTERNOON. TUESDAY...VFR CIRRUS THEN MVFR OR IFR CONDS DEVELOPING IN SNOW LATE IN THE DAY CHANGING TO ICE OR RAIN AT NIGHT. LIGHT SOUTH WIND. WEDNESDAY...VFR CIGS DEVELOPING AFTER ANY LEFTOVER MORNING IFR OR MVFR CONDS IN SHOWERS? SW WIND SHIFTING NW. && .MARINE... THE SCA WILL BE EXTENDED TILL 23Z ON THE OCEAN. SEAS HAVE LOWERED TO AROUND FIVE FEET AND WILL CONTINUE TO SLOWLY GET LOWER THROUGHOUT THE NIGHT. WAVEWATCH GUIDANCE LOOKS TO QUICK TO LOWER THE SEAS THROUGH SATURDAY MORNING. SEAS AND WINDS WILL REMAIN BELOW SCA CRITERIA THROUGH SATURDAY. CONTINUED NORTHWESTERLY WINDS ON SATURDAY AROUND 10 KNOTS.OUTLOOK... OUTLOOK... SATURDAY NIGHT - SUNDAY...SUB-SCA EXPECTED. SUNDAY NIGHT - MONDAY...POSSIBLE SCA CONDITIONS LATE ON SUNDAY AHEAD OF AN APPROACHING COLD FRONT WITH INCREASING SOUTHERLY WINDS AND BUILDING SEAS EXPECTED. NW GALE POTENTIAL FOR ABOUT 6 HOURS MONDAY MIDDAY AND AFTERNOON. TUESDAY...SUB-SCA EXPECTED. && .HYDROLOGY... TWO PRECIPITATION EVENTS ARE EXPECTED DURING THE EXTENDED PERIOD, ONE ON SUNDAY AFTERNOON INTO MONDAY MORNING AND A SECOND ONE ON TUESDAY NIGHT INTO WEDNESDAY NIGHT. THE INITIAL EVENT LOOKS TO BE ONE WITH SNOW OR MIXED WINTRY PRECIPITATION. THE SECOND EVENT ON TUESDAY NIGHT INTO WEDNESDAY NIGHT LOOKS TO BE ON THE LIQUID SIDE WITH TEMPERATURES WELL ABOVE FREEZING AFTER AN INITIAL WINTRY START. ALTHOUGH THIS SECOND EVENT IS ABOUT 5 DAYS OUT, WE WANTED TO HIGHLIGHT THAT SOME OF THE SOLUTIONS WE`RE SEEING ARE PRODUCING LOCALLY HEAVY RAINFALL. THE COMBINATION OF A BRIEF WARM UP ON WEDNESDAY, LOCALLY HEAVY RAIN, MELTING SNOW, A FROZEN GROUND, ABOVE NORMAL ICE IN CREEKS, STREAMS, AND RIVERS COULD LEAD TO INCREASED RUNOFF AND FLOODING. INCREASED FLOW 0N AREA CREEKS, STREAMS, AND RIVERS COULD ALSO START TO MOVE ICE, AND IN A WORST CASE SCENARIO, CREATE RESTRICTIONS OR JAMS. AGAIN, THIS SECOND EVENT BRINGING WARMTH AND RAIN IS ABOUT 5 DAYS OUT. THINGS CAN CHANGE. CONTINUE TO MONITOR FORECASTS. KEEP IN MIND THAT SNOWMELT AND WARMTH, BY THEMSELVES, TYPICALLY DON`T CAUSE FLOODING. HOW MUCH RAIN WE GET WILL BE THE DETERMINING FACTOR. && .CLIMATE...
-- Changed Discussion --
MIN TEMP RECORDS FOR FRI/27TH AND SAT/28TH. NO RECORDS WERE SET TODAY ALTHOUGH KACY WAS CLOSE...3 DEGREES OFF THIS MORNING. THERE IS A GREATER CHANCE OF RECORDS ON SATURDAY. POR / SITE / FEB 27 / FEB 28 1872 / KPHL / 6 1900 NO RER / 9 1934 RECORD IN JEOPARDY 1874 / KACY / 7 1934* NO RER / 2 1934 1894 / KILG / 5 1934 NO RER / -5 1934 1922 / KABE / -2 1963 NO RER /-10 1934 1869 / KRDG / 4 1934* NO RER / 3 1934 RECORD IN JEOPARDY 1865 / KTTN / 6 1934 NO RER / 1 1934 1948 / KGED / 10 1963 NO RER / 8 1950 1901 / KMPO / -9 1993 NO RER /-15 1907 KACY RER FOR 3/1 IS 5 IN 1980 AND KTTN 8 IN 1972. NOTE: * INDICATE AND OTHER YEARS. NOTE: POR = PERIOD OF RECORD, THE YEAR OFFICIAL CLIMATE OBS BEGAN. THE FOLLOWING IS A TABLE OF THE ***PROJECTED*** TOP 5 COLDEST FEBRUARY`S ON RECORD, BASED ON THE CURRENT FORECAST, AND THUS SUBJECT TO CHANGE. EACH RANKING DENOTES THE MEAN FEBRUARY TEMPERATURE (F) AND YEAR OF OCCURRENCE. WE REREVIEWED THESE PROJECTIONS LISTED BELOW USING THIS FRIDAY AFTERNOONS (27TH) MINS AND THE PHI FCST AS SEEN ON NDFD AND SFT`S. WE SEE PHL/ABE/ILG ALL VERY CLOSE TO PRIOR PROJECTIONS. POR / SITE / 1ST RANK / 2ND RANK / 3RD RANK / 4TH RANK / 5TH RANK 1872 / KPHL / 22.2(1934) 23.0(1979) 24.3(1885) 24.6(1978) 25.4(1895) 1874 / KACY / 21.6(1979) 23.6(1934) 23.8(1978) 24.9(2015) 25.5(1875) 1894 / KILG / 20.2(1934) 22.1(1979) 22.7(1978) 24.7(2015) 24.9(1936) 1922 / KABE / 16.6(1934) 19.0(2015) 20.4(1979) 21.6(1936) 22.0(1963) PER THE ABOVE TABLE, ABE IS EASILY ON TRACK FOR THE SECOND COLDEST FEBRUARY, BOTH ACY AND ILG 4TH COLDEST, AND PHL THE SIXTH COLDEST PROJECTED AT 25.5F (NOT SHOWN IN THE TABLE ABOVE). THE FOLLOWING IS A TABLE OF THE ***PROJECTED*** MEAN FEBRUARY 2015 TEMPERATURES (F) AND DEPARTURES FROM NORMAL. THIS IS ALSO BASED ON THE CURRENT FORECAST, AND THUS SUBJECT TO CHANGE. JANUARY 2015 MEAN TEMPERATURES ARE ALSO INCLUDED FOR COMPARISON PURPOSES. POR / SITE / FEB MEAN(F) / FEB NORMAL(F) / FEB DEP (F) / JAN MEAN(F) 1872 / KPHL / 25.5 / 35.7 / -10.2 / 30.9 1874 / KACY / 24.9 / 35.3 / -10.4 / 30.2 1894 / KILG / 24.7 / 35.1 / -10.4 / 30.3 1922 / KABE / 19.0 / 30.7 / -11.7 / 25.9 IN GENERAL, MEAN TEMPERATURES AT OUR FOUR MAJOR CLIMATE SITES ARE ON TRACK TO BE AROUND 10 TO 12 DEGREES BELOW NORMAL FOR FEBRUARY 2015. IT`S ALSO INTERESTING TO NOTE THAT THE PROJECTED FEBRUARY 2015 MEAN TEMPERATURES WILL BE WELL BELOW THE JANUARY 2015 MEAN TEMPERATURES. TO PUT THIS IN PERSPECTIVE, NORMAL MEAN FEBRUARY TEMPERATURES AT OUR FOUR MAJOR CLIMATE SITES ARE ON AVERAGE ABOUT 2 TO 3 DEGREES WARMER THAN JANUARY. THE CONVERSE IS SHAPING UP TO BE THE CASE FOR FEBRUARY 2015, AS MEAN TEMPS WILL BE 2 TO 3 DEGREES BELOW THOSE OBSERVED IN JANUARY. ALSO OF INTEREST, THIS WOULD ALSO BE THE SECOND OR THIRD COLDEST MONTHLY MEAN TEMPERATURE ON RECORD AT ALLENTOWN SINCE RECORDS BEGAN IN 1922, WITH FEBRUARY 1934 BEING THE COLDEST! OUR OTHER SITES RANK AS FOLLOWS: PHILADELPHIA PROJECTS AROUND 12TH COLDEST MONTHLY MEAN SINCE RECORDS BEGAN IN 1873. ATLANTIC CITY AROUND 7TH COLDEST MONTHLY MEAN SINCE RECORDS BEGAN IN 1874. WILMINGTON HAS MISSING DATA IN ITS DATABASE (1897-1916), AND SO WE DON`T FOCUS AS MUCH ATTENTION ON THAT RECORD.
-- End Changed Discussion --
&& .EQUIPMENT... KGED SUNSHINE MAXIMUM TEMPS LOOK FAR TOO WARM. A TROUBLE TICKET IS POSTED ON THIS TEMPERATURE SENSOR. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EST THIS EVENING FOR ANZ450>455. && $$ SYNOPSIS...DRAG NEAR TERM...GAINES SHORT TERM...GAINES LONG TERM...DRAG AVIATION...DRAG/GAINES MARINE...DRAG/GAINES HYDROLOGY...KRUZDLO CLIMATE...CORRECTED TOP 5 COLDEST FEB TABLE AT PHL AND ACY EQUIPMENT...GAINES/DRAG

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.