052  
FXUS61 KPHI 281140  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
640 AM EST FRI NOV 28 2014  
   
SYNOPSIS
 
 
HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE EAST COAST FROM  
TODAY INTO TONIGHT, BEFORE MOVING TO THE SOUTH AND EAST SATURDAY  
INTO SATURDAY NIGHT. A WARM FRONT MAY LIFT NORTH OF THE AREA  
SATURDAY NIGHT INTO SUNDAY. A COLD FRONT IS EXPECTED TO SAG DOWN  
ACROSS THE AREA SUNDAY NIGHT, BEFORE SLOWLY MOVING THROUGH THE  
AREA MONDAY INTO MONDAY NIGHT. HIGH PRESSURE WILL THEN BRIEFLY  
RETURN TO THE NORTHEAST FOR TUESDAY, FOLLOWED BY ANOTHER FRONTAL  
SYSTEM AROUND WEDNESDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
A MID LEVEL SHORT WAVE TROUGH WAS PASSING OVERHEAD EARLY THIS  
MORNING. THE FEATURE WILL MOVE OUT TO SEA.  
 
CLOUDS AND SCATTERED SNOW SHOWERS AND FLURRIES WILL LINGER IN OUR  
NORTHERN COUNTIES EARLY THIS MORNING IN THE DEVELOPING NORTHWEST  
FLOW. A FEW TENTHS OF AN INCH OF NEW SNOW IS POSSIBLE, MAINLY IN  
THE ELEVATED TERRAIN. OTHERWISE, WE ARE ANTICIPATING A MOSTLY  
SUNNY SKY FOR TODAY AS DRY AIR BUILDS INTO OUR REGION. HIGH  
CLOUDS MAY BEGIN TO OVERSPREAD OUR REGION FROM THE NORTHWEST  
DURING THE AFTERNOON.  
 
A GUSTY NORTHWEST WIND IS EXPECTED TO DEVELOP THIS MORNING AS THE  
SHORT WAVE MOVES FARTHER TO OUR EAST. WE ARE FORECASTING WIND  
SPEEDS AROUND 10 TO 15 MPH WITH GUSTS INTO THE 20S. MAXIMUM  
TEMPERATURES SHOULD RANGE FROM THE UPPER 20S IN THE POCONOS TO  
AROUND 40 DEGREES IN FAR SOUTHERN NEW JERSEY AND IN SOUTHERN  
DELAWARE.  
 

 
   
SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/
 
 
HIGH CLOUDS WILL CONTINUE TO BUILD OVERHEAD THIS EVENING. WARM  
ADVECTION IS FORECAST TO BEGIN OVER OUR REGION AS THE SURFACE  
RIDGE PASSES OFF THE COAST. WE ARE ANTICIPATING MID LEVEL CLOUDS  
TO DEVELOP IN THE ISENTROPIC LIFT. CEILINGS ARE EXPECTED TO LOWER  
GRADUALLY LATE TONIGHT AND WE MAY SEE SOME LIGHT SNOW SHOWERS POKE  
INTO OUR FORECAST AREA FROM THE WEST. ONLY A VERY LIGHT  
ACCUMULATION IS ANTICIPATED WITH THE BEST CHANCE IN OUR FORECAST  
AREA BEING IN EASTERN PENNSYLVANIA.  
 
THE WIND IS EXPECTED TO BECOME LIGHT AND VARIABLE. FAIRLY GOOD  
RADIATING CONDITIONS MAY BE PRESENT DURING THE EVENING AND  
TEMPERATURES ARE FORECAST TO FALL INTO THE TEENS IN OUR NORTHERN  
COUNTIES AND INTO THE 20S ELSEWHERE OVERNIGHT.  
 

 
   
LONG TERM /SUNDAY THROUGH THURSDAY/
 
 
OVERALL LOOKS LIKE A FAIRLY BENIGN PATTERN FOR THE MID-ATLANTIC  
REGION OVER THE NEXT FEW DAYS...WITH NO BIG STORMS ON THE HORIZON  
AND TEMPS GENERALLY WITHIN A FEW DEGREES OF NORMAL. THE FLOW ALOFT  
IS MAINLY ZONAL OVR THE NRN US WITH A COUPLE OF SHRTWV TROFS MOVG  
THROUGH ON MON AND AGAIN AROUND WED/THU. THE LATTER ONE IS FCST TO  
DIG A LITTLER DEEPER OVER THE ERN US AND HAS A BETTER CHC TO  
PRODUCE SOME LIGHT PRECIP. THE BEST ASSOCD FORCING FOR UVV REMAINS  
TO OUR NORTH AND MOISTURE SEEMS RATHER LIMITED.  
 
FOR SATURDAY...THE CURRENT COLD AIR MASS WILL BE LIFTING AWAY TO  
THE NE AND RESULTING WAA WILL PRODUCE CLOUDS AND POSSIBLY SOME  
LIGHT SNOW IN THE MORNING...MAINLY N OF PHL. AS HIGH PRES MOVES  
OFF THE COAST...WINDS BECOME SWLY AND CONTINUE THRU SUN AND MON  
AHEAD OF A COLD FRONT APPROACHING FROM THE NW. MAX TEMPS ON  
SUN/MON SHOULD BE A FEW DEGS ABOVE NORMAL. ATTM IT LOOKS LIKE THE  
FROPA WOULD BE SOMETIME AROUND MIDDAY MONDAY. THE FCST HAS CHC  
POPS FOR MON/MON NIGHT WITH POSSIBLY SOME LIGHT SNOW IN CAA BEHIND  
THE FRONT.  
 
HIGH PRES MOVES BY RATHER QUICKLY TO THE NORTH ON TUE...FOLLOWED  
BY ANOTHER FRONTAL SYSTEM ON WED. THIS ONE SEEMS TO HAVE A  
SLIGHTLY BETTER FORCING AND MOISTURE CONNECTION AND POPS ARE  
SLIGHTLY HIGHER FOR WED THAN MON. HWVR THERE IS A LOT OF  
UNCERTAINTY THAT FAR OUT. ATTM IT LOOKS LIKE TEMPS SHOULD BE WARM  
ENOUGH FOR MOSTLY RAIN.  
 

 
   
AVIATION /12Z FRIDAY THROUGH TUESDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
MAINLY VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD. EARLY  
MORNING CLOUDS SHOULD BE FOLLOWED BY CLEARING FOR THE DAYLIGHT  
HOURS. INCREASING AND LOWERING CLOUDS ARE EXPECTED FOR TONIGHT.  
THERE IS A CHANCE OF LIGHT SNOW SHOWERS AND FLURRIES LATE TONIGHT,  
ESPECIALLY AROUND KRDG AND KABE WHERE CONDITIONS MAY LOWER BRIEFLY  
INTO THE MVFR RANGE.  
 
A WEST NORTHWEST WIND AROUND 5 TO 10 KNOTS IS FORECAST FOR THE  
EARLY MORNING. THE WIND SPEEDS SHOULD INCREASE TO 8 TO 12 KNOTS  
DURING THE DAYLIGHT HOURS WITH GUSTS NEAR 20 KNOTS. THE WIND IS  
EXPECTED TO BECOME LIGHT AND VARIABLE TONIGHT AS HIGH PRESSURE  
BUILDS ACROSS OUR REGION.  
 
OUTLOOK...  
SATURDAY-MONDAY...MOSTLY VFR. WIND GUSTS 15-20 KNOTS EACH DAY;  
SOUTHWEST SATURDAY & SUNDAY, BECOMING NORTHWEST ON MONDAY.  
 
MONDAY NIGHT...CHANCE OF RAIN OR SNOW SHOWERS. GENERALLY VFR  
CONDS BUT TEMPORARILY LOWER IN PRECIPITATION. GUSTY NORTHWEST  
WINDS AROUND 20 KNOTS POSSIBLE.  
 
TUESDAY...MOSTLY VFR WITH NORTH WINDS.  
 

 
   
MARINE
 
 
A MID LEVEL SHORT WAVE TROUGH WAS PASSING OVERHEAD EARLY THIS  
MORNING. THE WEST NORTHWEST WIND WILL INCREASE IN ITS WAKE AND  
WIND GUSTS AROUND 25 OR 30 KNOTS ARE POSSIBLE ON OUR COASTAL  
WATERS, INCLUDING ON DELAWARE BAY, FOR MUCH OF THE DAY. AS A  
RESULT, A SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 600 PM.  
 
HIGH PRESSURE IS EXPECTED TO BUILD OVER OUR REGION FROM THE WEST  
FOR TONIGHT AND WIND SPEEDS WILL LIKELY DIMINISH.  
 
OUTLOOK...  
SATURDAY-SUNDAY...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED AS  
THE CENTER OF HIGH PRESSURE MOVES OUT OVER THE WATERS.  
 
MONDAY-MONDAY NIGHT...SMALL CRAFT ADVISORY CONDITIONS REMAIN  
POSSIBLE BEHIND THE COLD FRONT THAT MOVES ACROSS THE AREA.  
 
TUESDAY...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED AS HIGH  
PRESSURE AFFECTS THE WATERS.  
 

 
   
CLIMATE
 
 
WITH THANKSGIVING UPON US AND METEOROLOGICAL WINTER KNOCKING ON  
OUR DOOR, ITS OUR ANNUAL LOOK TO SEE HOW PAST WINTERS HAVE FARED  
BASED ON PRECEDING FALL PATTERNS AND TRENDS.  
 
OUR FORAY LAST FALL ABOUT THE WINTER OF 2013-14 WAS AN  
UNMITIGATED BUST AS THE NEGATIVE EASTERN PACIFIC OSCILLATION  
PATTERN (EPO) TOOK HOLD IN NOVEMBER AND NEVER LET GO THE ENTIRE  
WINTER. WHILE THE COLDER NOVEMBER TRENDED DOWN OUR WINTER  
TEMPERATURE ANALOGS TO ABOUT NORMAL, IT WAS NOWHERE NEAR ENOUGH.  
IT WAS ALSO ONLY THE SIXTH TIME (OUT OF FORTY SIX OCCURRENCES)  
THAT A BOTTOM THIRD WINTER FOLLOWED A WARM OCTOBER.  
 
ONCE AGAIN WE ARE HEADING INTO THIS WINTER WITH A RARER  
COMBINATION OF A WARM OCTOBER AND COLDER NOVEMBER JUST LIKE THE  
TWO PREVIOUS AUTUMNS.  
 
IN TERMS OF ENSO, THE LATEST CONSENSUS OF ALL DYNAMICAL AND  
STATISTICAL MODELS FOR THE WINTER SEASON IS FOR A WEAK EL NINO TO  
OCCUR. OF LATE THE EL NINO HAS LOOKED HEALTHIER AS A KELVIN WAVE  
AND A CURRENTLY ROBUST MJO CYCLE HAVE/WILL HELP BOOST SEA SURFACE  
TEMPERATURE ANOMALIES (SSTA). AS CPC HAS STATED, THERE IS STILL A  
SSTA AND ATMOSPHERIC RESPONSE DISCONNECT THAT EXISTS. THE LATEST  
GLOBAL WIND OSCILLATION READINGS, OUR ATMOSPHERE IS STILL IN AN  
ENSO NEUTRAL STATE EVEN IF WATER EASTERN TROPICAL PACIFIC  
TEMPERATURE ANOMALIES HAVE BECOME WARMER.  
 
WEAK EL NINOS SINCE 1950 IN PHILADELPHIA HAVE HAD AN AVERAGE  
TEMPERATURE OF 33.2 DEGREES AND AVERAGE SNOWFALL OF 21.8 INCHES.  
WEAK EL NINOS, LIKE MOST NON-UBER EL NINOS, FAVOR HAVING MORE  
MAJOR SNOW STORMS THAN THE CLIMATOLOGICAL AVERAGE. IN THE TEN WEAK  
EL NINOS SINCE 1950, PHILADELPHIA HAS HAD EIGHT SNOWFALL EVENTS OF  
SIX INCHES OR MORE, FOUR OF WHICH WERE TEN INCHES OR MORE. THE  
MOST COMMON MONTH FOR MAJOR SNOWS DURING WEAK EL NINOS IS JANUARY,  
BUT THEY HAVE OCCURRED IN EVERY MONTH FROM NOVEMBER THROUGH MARCH.  
 
LOOKING AT THE MIDDLE AND HIGH LATITUDES, ONCE AGAIN SNOW  
COVERAGE IN EURASIA WAS OFF TO THE RACES IN SEPTEMBER AND OCTOBER,  
EVEN FASTER THAN AUTUMN OF 2013. OCTOBER 2014 ONLY TRAILED OCTOBER  
1976 FOR TOTAL SNOW COVERAGE. IN THE SATELLITE ERA WHEN BOTH  
SEPTEMBER AND OCTOBER HAVE HAD ABOVE AVERAGE SNOW COVERAGE, 64  
PERCENT OF THE ENSUING PHILADELPHIA WINTERS HAVE BEEN SNOWIER THAN  
THE CURRENT AVERAGE AND HAD A 50/50 SPLIT WITH TEMPERATURES BEING  
EITHER ABOVE OR BELOW NORMAL. WHILE 64 PERCENT MAY NOT SOUND  
DEFINITIVE, SNOWFALL IS NOT A NORMAL DISTRIBUTION BECAUSE SEASONS  
LIKE 2013-14 SKEW UPWARD THE STATISTICAL AVERAGE. SINCE 1967 (THE  
START OF THE SATELLITE ERA AND OUR LOOK AT THE DR. JUDAH COHEN  
STUDY) ONLY 1 IN 3 WINTERS HAS HAD ABOVE AVERAGE SNOWFALL. THE  
STATISTICAL MEDIAN FOR SNOWFALL IN PHILADELPHIA SINCE 1967 IS  
ABOUT 18 INCHES.  
 
BEYOND SIBERIA, THE ARCTIC OSCILLATION AVERAGED NEGATIVE DURING  
THE MONTH OF OCTOBER. WHEN IT HAS, 70 PERCENT OF ENSUING WINTERS  
HAS AVERAGED NEGATIVE. THANK-YOU METEOROLOGIST MATT LANZA FOR THIS  
INFORMATION. ANOTHER PHENOMENON THAT FAVORS A NEGATIVE ARCTIC  
OSCILLATION FOR THIS UPCOMING WINTER IS THAT WE ARE IN THE  
EASTERLY PHASE OF THE QUASI-BIANNUAL OSCILLATION STRATOSPHERIC  
WINDS OVER THE TROPICS. WHEN WE ARE IN THIS PHASE, HISTORICALLY WE  
HAVE HAD MORE SUDDEN STRATOSPHERIC WARMING EVENTS WHICH OFTEN  
SPLITS AND DISPLACES EVERYBODY'S FAVORITE POLAR VORTEX FROM NEAR  
THE NORTH POLE. THERE IS NO GUARANTEE THE WESTERN HEMISPHERE WOULD  
BE THE SO CALLED BENEFICIARY OF THIS ARCTIC DISPLACEMENT, BUT A  
HIGHER CHANCE EXISTS THIS WINTER VS NO CHANCE AT ALL.  
 
THE ARCTIC OSCILLATION'S COUSIN, THE NORTH ATLANTIC OSCILLATION  
(NAO), WE HAVE SEEN BEEN THE DRIVER (WINTER OF 2010-11) OR THE  
CRICKET CHIRPING (LAST WINTER) RECENTLY. UNFORTUNATELY THIS  
IMPORTANT TELECONNECTION INDEX IS TOUGH TO OUTLOOK MORE THAN WEEKS  
IN ADVANCE. WHILE THE ARCTIC OSCILLATION AND NORTH ATLANTIC  
OSCILLATION NORMALLY WORK IN TANDEM, ITS NOT ALWAYS THE CASE.  
SINCE 1950, 60 PERCENT OF ALL WINTERS HAVE AVERAGED A NEGATIVE  
ARCTIC OSCILLATION, BUT ONLY 42 PERCENT OF ALL WINTERS HAVE  
AVERAGED A NEGATIVE NORTH ATLANTIC OSCILLATION. THE LATE JACK  
ORDILLE POINTED US TO A RESEARCH PAPER USING NEWFOUNDLAND REGION  
SPRING-SUMMER SEA SURFACE TEMPERATURE ANOMALIES AS A PREDICTOR OF  
THE NAO FOR THE ENSUING WINTER. IT HAS WORKED WELL THE LAST COUPLE  
OF WINTERS (HERE COMES THE JINX) AND IT FAVORS A NEGATIVE NAO FOR  
THIS UPCOMING WINTER.  
 
THIS BRINGS US TO OUR LAST (BUT NOT LEAST) OSCILLATION INDEX, THE  
PACIFIC DECADAL OSCILLATION (PDO). CURRENTLY THE OSCILLATION IS IN  
TEXTBOOK POSITIVE POSITION. SO MUCH SO, THAT WHEN ITS BEEN THIS  
POSITIVE DURING THE MONTH OF OCTOBER, IT HAS NEVER AVERAGED  
NEGATIVE (HERE COMES ANOTHER ANNOUNCER'S JINX: 15 OF 15 TIMES  
SINCE 1900) DURING THE UPCOMING WINTER. ELEVEN OF THOSE WINTERS  
HAVE AVERAGED COLDER THAN THE CURRENT AVERAGE (AND AVERAGED AROUND  
20 INCHES OF SNOW) IN PHILADELPHIA. HISTORICALLY ABOUT 2/3RDS OF  
ALL WINTERS SINCE 1900 HAVE AVERAGED COLDER THAN NORMAL IN  
PHILADELPHIA WHEN THE PDO HAS AVERAGED POSITIVE. IN FACT, THE  
GREATEST POINT OF FAILURE WHEN WARM OCTOBERS HAVE NOT BEEN  
FOLLOWED BY WARMER WINTERS HAS BEEN WHEN THE PDO HAS BEEN STRONGLY  
POSITIVE IN THE AUTUMN.  
 
LOCALLY, OF THE 46 WARMEST WINTERS IN PHILADELPHIA ON RECORD,  
HALF OF THEM HAVE OCCURRED AFTER A WARM OCTOBER. GIVEN THE STATE  
OF THE PDO, WE DONT HAVE A WARM FEELING ABOUT THAT THIS WINTER.  
THIS NOVEMBER WILL END AGAIN CLOSE TO THE CUSP BETWEEN THE  
UNSEASONABLY COLD AND NORMAL TERCILES. REGARDLESS THIS IS A RARER  
OCCURRENCE AND A CONTRADICTION IN THE STUDY FIRST DONE IN WHICH  
THE STRONGEST CORRELATOR FOR A WARM WINTER IS A WARM OCTOBER WHILE  
THE STRONGEST CORRELATOR FOR A COLD WINTER IS A COLD NOVEMBER. IN  
2012 OCTOBER WON, LAST YEAR NOVEMBER WON. UNLIKE THE LAST TWO  
WINTERS, WE ARE EXPECTING A WEAK EL NINO AND NOT ENSO NEUTRAL  
NEGATIVE. WHILE THE PACIFIC FAVORS COLD AGAIN, THE TYPE OF COLD  
LOOKS DIFFERENT AS POSITIVE SEA SURFACE TEMPERATURE ANOMALIES ARE  
FARTHER EAST THAN THEY WERE LAST AUTUMN.  
 
SO HERE ARE OUR ANALOGS FOR THE UPCOMING WINTER. THEY ARE BASED  
ON WARMER THAN CURRENT NORMAL OCTOBERS AND COLDER THAN CURRENT  
NORMAL NOVEMBERS. THE ANALOGS ARE A COMBINATION OF MODERATE, WEAK  
AND ENSO POSITIVE WINTERS. SEVEN OF THESE ALSO HAD POSITIVE PDO(S)  
DURING THE WINTER, THE ONE EXCEPTION (1953-4) WE KEPT BECAUSE IT  
WAS A WEAK EL NINO AND IT ALSO WAS A SNOWY NOVEMBER. AS ALWAYS  
PAST PERFORMANCE MAY NOT BE AN INDICATOR OF FUTURE TRENDS....AND  
NOW TO THE GREAT EIGHT:  
 
 
 
SEASON DEC JAN FEB WINTER SEASONAL WINTER  
AVG AVG AVG AVG SNOWFALL PCPN  
 
 
1905-06 39.2 39.4 33.6 37.4 20.5 8.61  
1914-15 33.3 36.6 38.6 36.2 32.5 19.64  
1939-40 38.1 25.3 34.8 32.7 22.3 7.77  
1941-42 38.3 30.5 30.8 33.2 10.3 9.24  
1951-52 38.7 37.3 38.2 38.1 16.2 12.21  
1953-54 39.4 31.7 41.7 37.6 22.6 7.58  
1986-87 37.9 31.9 32.5 34.1 25.7 11.64  
2002-03 35.4 28.6 29.9 31.3 46.3 11.02  
 
AVG 37.5 32.7 35.0 35.1 24.6 11.59  
1981-2010 NML 37.5 33.0 35.7 35.4 22.4 9.24  
 
THE OFFICIAL CPC OUTLOOK FOR THE WINTER IS FOR EQUAL CHANCES OF  
IT BEING EITHER WARMER OR COLDER THAN NORMAL AND A GREATER CHANCE  
OF IT BEING WETTER THAN NORMAL.  
 
WE HOPE EVERYONE HAD A GREAT THANKSGIVING AND WE HOPE YOU WILL  
HAVE A HAPPY UPCOMING HOLIDAY SEASON. MAY THIS WINTER BE BEYOND  
YOUR WILDEST EXPECTATIONS.  
 

 
   
EQUIPMENT
 
 
KDIX WSR-88D RADAR IS INOPERATIVE. TECHNICIANS HAVE BEEN NOTIFIED  
AND WILL TROUBLESHOOT THE ISSUE. TPHL TDWR SHOULD PROVIDE  
SUFFICIENT BACKUP RADAR COVERAGE.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-  
431-450>455.  
 

 
 

 
 
SYNOPSIS...AMC  
NEAR TERM...IOVINO  
SHORT TERM...IOVINO  
LONG TERM...AMC  
AVIATION...AMC/IOVINO  
MARINE...AMC/IOVINO  
CLIMATE...GIGI  
EQUIPMENT...STAFF  
 
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