-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 130933
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
533 AM EDT THU MAR 13 2014

.SYNOPSIS...
WITH THE STRONG COLD FRONT CONTINUING TO MOVE OFFSHORE TODAY HIGH
PRESSURE WILL BUILD TO OUR SOUTH THROUGH AND FRIDAY. A WARM FRONT
MAY LIFT ACROSS THE AREA FRIDAY AS AN AREA OF LOW PRESSURE MOVES
THROUGH SOUTHEASTERN CANADA. A COLD FRONT ASSOCIATED WITH THIS LOW
WILL MOVE ACROSS THE AREA EARLY SATURDAY, FOLLOWED BY ANOTHER EARLY
SUNDAY. HIGH PRESSURE WILL TRY TO BUILD OUT OF SOUTH CENTRAL CANADA
AND DOWN ACROSS THE NORTHEAST LATE IN THE WEEKEND INTO EARLY NEXT
WEEK WHILE ANOTHER COASTAL STORM MAY DEVELOP OFF THE SOUTHEAST COAST
AND MOVE NEAR THE MID ATLANTIC REGION SUNDAY NIGHT INTO MONDAY.
ANOTHER SYSTEM LOOKS TO LIFT THROUGH TO OUR NORTHWEST LATE ON
WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT IS NOW WELL EAST OF THE REGION, BUT THE STRONG POST
FRONTAL WINDS CONTINUE. THERE HAS BEEN A SLIGHT DOWNWARD TREND,
GENERALLY, IN THE WIND SPEEDS. THIS WAS ALSO DEPICTED IN THE LAMP
GUIDANCE, BUT ONLY TEMPORARILY, WITH WIND SPEEDS COMING BACK UP INTO
WIND ADVISORY AROUND 12Z, AND REMAIN THERE THROUGH MUCH OF THE DAY.
GIVEN THAT THE PRESSURE GRADIENT OVER THE REGION WILL REMAIN AROUND
5 TO 6 MB/100 MI THROUGH AT LEAST MID DAY, AGREE THAT THIS LULL IN
THE WINDS IS LIKELY ONLY TEMPORARY. THUS, NO CHANGES TO THE
HEADLINES RIGHT NOW.

PRESSURE GRADIENT DECREASES RAPIDLY AFTER 18Z AS THE LOW CONTINUES
TO LIFT NE AND THE SURFACE RIDGE BUILDS FROM THE SOUTH. WINDS WILL
FOLLOW, WITH SPEEDS DECREASING THROUGH THE DAY.

WITH THE NORTHWESTERLY LOW LEVEL FLOW, AND THUS COLD AIR ADVECTION
CONTINUING THROUGH THE DAY, IT WILL BE VERY COLD TODAY. ABOUT 20
DEGREES BELOW NORMAL, OR TO PUT IT ANOTHER WAY - 20 TO 40 DEGREES
LESS THAN YESTERDAYS HIGHS!

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
THE BIGGEST CONCERN TONIGHT WILL BE THE TEMPERATURES. THOUGH MID AND
UPPER LEVEL CLOUDS WILL BE ON THE INCREASE, THUS NOT QUITE PRIME
RADIATIONAL COOLING CONDITIONS, THE DECREASING WINDS AND DRY AIR IN
PLACE, WILL ALLOW TEMPERATURES TO PLUMMET INTO THE SINGLE DIGITS AND
TEENS FOR MUCH OF THE REGION.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
SURFACE RIDGING MOVES ACROSS THE REGION ON FRIDAY DEVELOPING A
RETURN FLOW AND A POSSIBLE WARM FRONT PASSING THROUGH. WE WILL BE
DRY ON FRIDAY, UNDER THE INFLUENCE OF THE RIDGE, WITH WARMING
TEMPERATURES. LIKE THE DAY BEFORE THE TEMPERATURE CHANGE WILL BE
SUBSTANTIAL AS WE SHOULD CLIMB NEARLY 20 DEGREES BRINGING US BACK
TOWARDS THE NORMAL MARK.

ANOTHER WEAKENING COLD FRONT WILL SWEEP THROUGH THE REGION EARLY ON
SATURDAY WITH A COUPLE OF SHOWERS ASSOCIATED WITH IT. THERMAL
PROFILES WOULD SUGGEST A RAIN/SNOW MIXTURE THOUGH WITH LITTLE IN THE
WAY OF QPF NOT EXPECTING MUCH ACCUMULATIONS, IF IT WERE ALL FROZEN
PRECIPITATION.

SATURDAY WILL BE EVEN WARMER AS WEST-SOUTHWEST WINDS DEVELOP BEHIND
THE WEAK COLD FRONT. THE DOWNSLOPING FLOW AND AMPLE SUNSHINE SHOULD
BE ENOUGH TO PROPEL MOST SPOTS ANOTHER 10 DEGREES FROM FRIDAYS HIGHS.
ANOTHER FRONTAL BOUNDARY, THIS ONE SHOULD BE COMPLETELY DRY, WILL
USHER IN ANOTHER AIRMASS CHANGE AS WE DROP BACK TOWARDS AVERAGE FOR
MID-MARCH.

THE NEXT SYSTEM OF INTEREST BEGINS TO DEVELOP ALONG THE FRONTAL
BOUNDARY THAT JUST DRAPED THROUGH THE REGION. THERE IS STILL A LOT
OF UNCERTAINTY WITH THIS SYSTEM AS THE MID-LEVEL PATTERN DOESN`T
PROVIDE A GOOD CONSENSUS AMONGST THE MID-RANGE GUIDANCE. LEANED
HEAVILY ON THE WPC GUIDANCE AT THIS POINT BRINGING CHANCE POPS INTO
THE REGION LATE SUNDAY NIGHT INTO MONDAY. THERMAL PROFILES AT THIS
POINT WOULD INDICATE WIDESPREAD SNOW ACROSS THE NORTHERN HALF OF THE
CWA WITH A BIT MORE MIXING ACROSS THE SOUTH BEFORE CHANGING OVER. STILL
PLENTY OF TIME TO FIGURE OUT HOW THIS SYSTEM WILL TRACK.

PRECIPITATION CHANCES DIMINISH AS WE MOVE INTO MONDAY NIGHT AND
TUESDAY AS THE AFOREMENTIONED STORM MOVES TO OUR NORTHEAST AND HIGH
PRESSURE BRIEFLY BUILDS ACROSS THE AREA. THEN MODELS DIVERGE WITH
WHAT TO DO WITH THE NEXT POTENTIAL SYSTEM. FOR TUESDAY NIGHT INTO
WEDNESDAY, THE GFS BRINGS A LOW ACROSS SOUTHEASTERN CANADA, WHILE
THE ECMWF BRINGS A LOW RIGHT OVER OUR AREA. WITH THE SPREAD AND
UNCERTAINTY, WE FOLLOWED CLOSELY TO WPC WHICH IS SOMEWHERE IN
BETWEEN AND INTRODUCES CHANCE POPS ACROSS THE AREA AROUND WEDNESDAY.

&&

.AVIATION /10Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

MVFR CEILINGS LEFT AROUND SOME PARTS OF THE REGION WILL ERODE BY
12Z, LEAVING VFR CONDITIONS THROUGH THE REST OF THE TAF PERIOD.
WINDS WILL STAY GUSTY OUT OF THE NW THROUGH THE DAY, BEFORE FINALLY
DECREASING TO NEAR 10KT AFTER SUNSET THIS EVENING.

OUTLOOK...
FRIDAY...VFR. WINDS VEER TOWARDS THE SOUTHWEST AND COULD BE GUSTY AT
TIMES.

SATURDAY...MOSTLY VFR. COLD FRONT WILL CROSS THE REGION ON SATURDAY
WITH SUB-VFR POSSIBLE IN RAIN/SNOW SHOWERS EARLY NORTH OF RDG/ABE.

SUNDAY...VFR.

SUNDAY NIGHT-MONDAY...MVFR/IFR CONDITIONS POSSIBLE WITH SNOW
POSSIBLE FOR SOUTHEAST/COASTAL AREAS. MOSTLY VFR EXPECTED FOR
CENTRAL AND NORTHWESTERN TAFS OUTSIDE OF SNOW. GUSTY NE WINDS 20-25
KT.

&&

.MARINE...
UPDATE...GUSTS CONTINUE TO TREND DOWN ON THE LOWER DELAWARE BAY,
SO HAVE REPLACED THE STORM WARNING WITH A GALE WARNING FOR THE
LOWER DELAWARE BAY AND ADJACENT OCEAN WATERS.

GUSTY WINDS WILL CONTINUE FOR MUCH OF THE DAY. DO NOT EXPECT TO
SEE WINDS DECREASE BELOW GALES, AT LEAST ON THE OCEAN WATERS,
UNTIL AFTER SUNSET TONIGHT. WITH THE COLD CONDITIONS AND CONTINUED
STRONG WINDS, SHOULD SEE LIGHT FREEZING SPRAY AT LEAST THROUGH THE
DAY TODAY.

OUTLOOK...
FRIDAY...SCA LIKELY WITH WINDS VEERING TOWARDS THE SOUTHWEST.

SATURDAY - SUNDAY...SUB-SCA CONDITIONS EXPECTED BY LATE SATURDAY
MORNING. WINDS SHIFT BACK TOWARDS THE WEST-NORTHWEST BEHIND A COLD
FRONT LATER ON SATURDAY.

SUNDAY NIGHT-MONDAY...RETURN TO SMALL CRAFT ADVISORY CONDITIONS
POSSIBLE WITH POSSIBLE COASTAL LOW.

&&

.FIRE WEATHER...
WITH MIN RH VALUES EXPECTED TO BE BETWEEN 20 AND 30 PERCENT, AND
CONTINUED GUSTY WINDS THROUGH THE DAY, WILL ISSUE AN SPS FOR THE
FIRE WEATHER CONCERNS ACROSS DELMARVA AND SOUTHERN NJ. AREAS NORTH OF
I-195 IN NEW JERSEY AS WELL AS EASTERN PENNSYLVANIA ARE EXPECTED TO
HAVE MOIST ENOUGH FUELS TO PRECLUDE THE NEED FOR ANY SPS STATEMENTS.

FRIDAY WILL SEE A SLIGHT INCREASE IN RELATIVE HUMIDITY VALUES WITH
MORE OF A SOUTHWESTERLY FLOW. WINDS SHOULD INCREASE A BIT DURING
THE AFTERNOON HOURS AND COME CLOSE TO 20MPH GUSTS.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 11 AM EDT THIS MORNING FOR PAZ054-055-
     060>062-070-071-101>106.
NJ...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NJZ001-007>010-
     012>015.
     WIND ADVISORY UNTIL 11 AM EDT THIS MORNING FOR NJZ016>027.
DE...WIND ADVISORY UNTIL 11 AM EDT THIS MORNING FOR DEZ001>004.
MD...WIND ADVISORY UNTIL 11 AM EDT THIS MORNING FOR MDZ008-012-015-
     019-020.
MARINE...GALE WARNING UNTIL 1 AM EDT FRIDAY FOR ANZ450>455.
     GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ430-431.

&&

$$
SYNOPSIS...HEAVENER/ROBERTSON
NEAR TERM...JOHNSON
SHORT TERM...JOHNSON
LONG TERM...HEAVENER/ROBERTSON
AVIATION...HEAVENER/JOHNSON
MARINE...HEAVENER/JOHNSON
FIRE WEATHER...