Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
000
FXUS61 KPHI 051124
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
624 AM EST THU MAR 5 2015

.SYNOPSIS...
A COUPLE OF WAVES OF LOW PRESSURE WILL TRACK SOUTHEAST OF THE
REGION TODAY AND THIS EVENING. A HIGH PRESSURE SYSTEM WILL
MOVE INTO THE REGION ON FRIDAY AND THEN SINK TO THE SOUTHEAST ON
SATURDAY. A WEAK CLIPPER TYPE LOW PRESSURE SYSTEM SHOULD PASS
NORTH OF THE AREA ON SATURDAY NIGHT FOLLOWED BRIEFLY BY ANOTHER
HIGH PRESSURE SYSTEM ON SUNDAY. A COLD FRONT SHOULD PASS THROUGH THE
REGION ON MONDAY. ANOTHER HIGH PRESSURE SYSTEM SHOULD THEN BUILD
INTO THE AREA ON TUESDAY AND WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE RAIN/SNOW LINE HAS PUSHED SOUTH/EAST AND IS ROUGHLY ALONG THE
I-95 CORRIDOR ATTM. THIS TRANSITION HAS OCCURRED SOMEWHAT SLOWER
THAN EARLIER ENVISIONED...YET THERE IS STILL PLENTY OF MOISTURE
UPSTREAM AND DECENT SNOWS ARE STILL EXPECTED TODAY. LIGHT ACCUMS
ALREADY BEING REPORTED N/CNTRL NJ AND NE PA/LEHIGH VALLEY.


THE COLD FRONT AND THE WEAK AREA OF LOW PRESSURE MOVING ALONG IT ARE
BOTH SOUTH OF THE AREA THIS MORNING. THE SHIELD OF PRECIPITATION
CONTINUES ACROSS THE AREA AND THERE APPEARS TO BE PLENTY OF MOISTURE
UPSTREAM STILL TO GO THROUGH. TEMPERATURES CONTINUE THE SLOW DROP
ACROSS THE AREA AND RAIN HAS CHANGED TO SNOW ACROSS NE PA AND THE
LEHIGH VALLEY AS OF PRESS TIME. THE PRECIP WILL CONTINUE TO CHANGE
ACROSS THE DEL VALLEY BY DAWN AND THEN ACROSS SRN NJ AND THE
DELMARVA LATER THIS MORNING. THE SNOW AMTS EARLIER STILL LOOK MOSTLY
OK...AND ONLY SLIGHT ADJUSTMENTS WERE MADE. A WIDE SWATH OF 6 TO 8
INCHES ACROSS THE CENTRAL PARTS OF THE CWA WITH 4-6 SURROUNDING
THAT. THE LOWEST TOTALS WILL BE ACROSS THE SRN POCONOS AND NRN NJ
WHERE 2-4 INCHES SHOULD FALL. TEMPERATURE WILL NOT CLIMB MUCH TODAY
WITH A CONTINUATION OF CAA EXPECTED.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
THE LAST OF THE STEADY SNOWS WILL PASS EAST OF THE FORECAST AREA
THIS EVENING. SKIES WILL BE CLOUDY EARLY THEN THE CLOUDS WILL BREAK
UP FROM N/W TO S/E OVERNIGHT. THE LACK OF CLOUDS LATE AND THE FRESH
SNOW COVER SHOULD PRODUCE COLD TEMPS OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND A FEW SUB-ZERO READINGS FAR NORTH. WIND CHILLS MAY
DROP TO NEAR -12 TO -15 ACROSS MOUNT POCONO...BUT REMAIN MORE LIKE 0
TO -10 ELSEWHERE. WINDS WILL BE MOSTLY NRLY AT 5 TO 10 MPH.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE GFS INITIALIZATION LOOKED SLIGHTLY BETTER THERMALLY, BUT IT
WAS A COLD OP RUN IN COMPARISON TO ITS ENSEMBLE MEAN AND OTHER
MODELS. OVERALL AFTER TODAY, THE LONG TERM IS RELATIVELY QUIET
WITH TEMPERATURES RETURNING TO NEAR NORMAL VALUES AND NOT MUCH
PCPN EXPECTED.

A BRIGHT SUNNY DAY IS EXPECTED ON FRIDAY WITH NOT MUCH WIND. THE
ONE CATCH IS THAT TEMPERATURES WILL BE WELL BELOW AVERAGE, EVEN
IF IT WERE STILL JANUARY. MAX TEMPS ARE CLOSE TO THE FULL SUN
MACROS AND THE HIGHER NAM STAT GUIDANCE.

ON FRIDAY NIGHT WE CONTINUED THE IDEA OF GOING EITHER WITH THE LOWER
STAT GUIDANCE IN URBAN AREAS OR BELOW ALL FOR MINS GIVEN WE ARE
EXPECTING RADIATIONAL COOLING CONDITIONS. THERE IS A SHORT WAVE
TROF THAT MIGHT SPILL SOME CLOUDS THROUGH PART OF THE NIGHT, ONLY
REASON WE DID NOT GO EVEN LOWER.

SATURDAY THE AIR MASS RECOVERY WILL START AS A HIGH PRESSURE SYSTEM
REACHES THE COAST. THERE SHOULD BE MORE CLOUDS AROUND ASSOCIATED
WITH THE WAA PHASE OF THE CLIPPER WHICH SHOULD SLOW TEMP RISE A
BIT. WE ARE CLOSER TO NAM STAT GUIDANCE FOR MAX TEMPS AS BY NOW
THE GEFS MEAN IS WARMER THAN THE OP GFS.

ON SATURDAY NIGHT, CONTINUED WITH THE IDEA THAT THE WEAKENING
CLIPPER MIGHT BRING SOME SNOW SHOWERS TO THE NORTHERN PART OF OUR
CWA. PRECIPITATION INTENSITY AS OF NOW APPEARS LIGHT IF THEY MAKE
IT. SUNDAY, THE MODERATION TREND IS EXPECTED TO CONTINUE AS THE
CLIPPER`S DEMISE SHOULD NOT BRING ANY COLDER AIR BACK INTO THE
REGION.

A NORTHERN STREAM COLD FRONT COULD BRING THE CHANCE OF SHOWERS BACK
INTO THE AREA ON MONDAY AND BY THEN IT MIGHT BE WARM ENOUGH FOR THE
PTYPE TO FALL AS RAIN. A SOUTHERN STREAM LOW PRESSURE SYSTEM IS
EXPECTED TO REMAIN SEPARATE WITH ITS PREDICTED PCPN FOR NOW
REMAINING SOUTHEAST OF OUR AREA.

THEN A HIGH PRESSURE SYSTEM ENTERING FROM THE PACIFIC OCEAN
(INSTEAD OF TAKING THE POLAR ROUTE) FOR A CHANGE IS EXPECTED TO
BRING TEMPERATURES CLOSE TO SEASONAL LEVELS FOR TUESDAY AND
WEDNESDAY.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

CONDITIONS WILL CONTINUE TO DETERIORATE THIS MORNING WITH
CIGS/VSBYS DROPPING TO IFR/LIFR IN SNOW. THE CHANGE-OVER HAS ALREADY
OCCURRED AT KRDG/KABE AND WILL SOON HAPPEN ACROSS THE DEL VALLEY
SITES. A FEW PERIODS OF SLEET ARE POSSIBLE...BUT PROBABLY WON`T LAST
TOO LONG AND WE`LL KEEP IT FROM THE TAFS WITH CONFID IN
LOCATION/TIMING RATHER LOW. SNOW WILL LOWER VSBYS WILL OCCUR MUCH OF
THE MORNING AND EARLY AFTERNOON BEFORE ENDING BY EVENING OVER MOST
AREAS. A RETURN TO VFR EXPECTED 23Z OR 00Z N/W AND 03Z TO 04Z S/E
WINDS WILL BE MOSTLY NW OR N AT 10 TO 15 KTS TODAY.


OUTLOOK...
FRIDAY THROUGH SATURDAY...PRIMARILY VFR.

SATURDAY NIGHT...SOME MVFR CIGS POSSIBLE, MAINLY NORTH ALONG
WITH A LOW CHANCE OF SNOW SHOWERS.

SUNDAY AND SUNDAY NIGHT...PRIMARILY VFR.

MONDAY...PRIMARILY VFR, LOCALLY MVFR IN SHOWERS.

&&

.MARINE...
WE WILL KEEP THE SCA FLAG FOR TODAY...AND EXTEND THE EXPIRATION TIME
INTO TONIGHT. WINDS AND SEAS WILL INCREASE ACROSS THE WATERS AS CAA
CONTINUES. IT APPEARS THAT GUSTS IN THE 25 TO 30 KNT RANGE ARE
POSSIBLE ACROSS THE OCEAN WATERS AND AROUND 20 KTS ACROSS DEL BAY.
THERE WILL BE RAIN/SNOW EARLY TODAY...THEN SNOW INTO THE AFTERNOON.
FAIR WEATHER EXPECTED TONIGHT.

OUTLOOK...
FRIDAY AND FRIDAY NIGHT...CONDITIONS SHOULD RETURN TO
SUB SMALL CRAFT ADVISORY LEVELS. FREEZING SPRAY IS LIKELY, NOT
CONFIDENT ENOUGH ABOUT MODERATE FREEZING SPRAY OCCURRING ON
FRIDAY MORNING TO ISSUE AN ADVISORY.

SATURDAY THROUGH MONDAY...SUB SMALL CRAFT ADVISORY CONDITIONS
ARE OUTLOOKED TO PREVAIL MAINLY DUE A COMBINATION OF RELATIVELY
WEAK PRESSURE SYSTEMS AND ALSO WHERE THERE WILL BE STRONGER WINDS
ABOVE THE BOUNDARY LEVEL, IT SHOULD BE AT TIMES WHEN THE
AIR TEMPS WILL BE HIGHER THAN THE WATER TEMPS.

&&

.HYDROLOGY...
WITH THE TRANSITION BACK TO SNOW TODAY (IF NOT ALREADY), THE
HYDROLOGICAL CONCERNS AT LEAST IN THE NEAR TERM ARE LESSENING.
WE ARE STILL MONITORING GAGED SITES TO CHECK FOR JAMS.

&&

.CLIMATE...
CLIMATE: WITH A SNOWCOVER IN PLACE AND ANOTHER MODIFIED ARCTIC
AIRMASS SETTLING INTO THE REGION AND RADIATIONAL COOLING OCCURRING,
WE HAVE ANOTHER CHANCE FOR MORE RECORD LOWS ACROSS THE REGION.

FRIDAY 3/6

RECORD LOWS

ACY 10 1888
PHL 10 1978
ILG 11 1926
ABE 7  1960
TTN 7  1872
GED 10 1978
RDG 7  1978
MPO -5 1909


THE CURRENT FORECAST CURRENTLY HAS MOST LOCATIONS BREAKING THERE
RECORD LOW ON FRIDAY MORNING. THE ONE EXCEPTION WOULD BE MOUNT
POCONO.

SATURDAY 3/7

RECORD LOWS

ACY 10 1890
PHL 9  1960
ILG 11 1960
ABE 1  1960
TTN 7  1890
GED 3  1960
RDG 10 1989
MPO -18 1911

ASIDE FROM ATLANTIC CITY, MOST LOCATIONS ARE FORECASTED TO BE SEVERAL
DEGREES WARMER THAN THE RECORD LOWS FOR SATURDAY MORNING.

RECORD DAILY SNOWFALL FOR THURSDAY MARCH 5

KACY 0.3 - 1960
KILG 3.7 - 1981
KABE 7.0 - 1917
KPHL 8.8 - 1981

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ054-
     055-061-062.
     WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR PAZ060-
     070-071-101>106.
NJ...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NJZ001-
     007-008.
     WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR NJZ009-
     010-012>027.
DE...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR
     DEZ001>004.
MD...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MDZ008-
     012-015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...GIGI
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...GIGI
AVIATION...GAINES/GIGI/O`HARA
MARINE...GIGI/O`HARA
HYDROLOGY...
CLIMATE...


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