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Area Forecast Discussion
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000
FXUS61 KPHI 282318
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
618 PM EST WED JAN 28 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE IN FROM THE OHIO VALLEY TONIGHT AND
OFFSHORE ON THURSDAY. LOW PRESSURE WILL MOVE ACROSS THE GREAT
LAKES THURSDAY NIGHT AND REFORM NEAR CAPE COD ON FRIDAY. THIS WILL
CAUSE AN ARCTIC FRONT TO CROSS THE REGION FRIDAY AFTERNOON. MORE
HIGH PRESSURE WILL MOVE IN FROM THE OHIO VALLEY AND OVER THE
REGION THIS WEEKEND. A COMPLEX STORM SYSTEM WILL AFFECT THE REGION
EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
HIGH PRESSURE WILL SLIDE INTO OUR AREA TONIGHT BEFORE STARTING TO
SHIFT SOUTH BY THURSDAY MORNING.

THE TIGHT PRESSURE GRADIENT ACROSS OUR REGION TODAY WILL RELAX.
OVERNIGHT WINDS WILL BECOME LIGHT AND VARIABLE ACROSS THE REGION.
IN ADDITION, SKIES WILL REMAIN CLEAR AND WE SHOULD RADIATE WELL
ONCE AGAIN TONIGHT. SNOW COVER DID DIMINISH IN THE BRIGHT SUN
TODAY BUT PARTS OF THE REGION WILL CONTINUE TO HAVE SNOW ON THE
GROUND OVERNIGHT, MAINLY THROUGH THE LEHIGH VALLEY, SOUTHERN
POCONOS, AND NEIGHBORING AREAS.

TEMPERATURES WERE A BLEND OF THE MET/MAV MOS BUT WERE EDGED DOWN
A BIT, ESPECIALLY IN AREAS WHERE THERE IS STILL SNOW ON THE
GROUND. EXPECT SINGLE DIGITS TO THE NORTH AND WEST OF PHILADELPHIA
WITH TEENS TO THE SOUTH AND EAST.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THE HIGH PRESSURE WILL SHIFT TO OUR SOUTH AND EAST ON THURSDAY AS
A LOW PRESSURE SYSTEM TRACKS TOWARD THE MID ATLANTIC FROM THE
GREAT LAKES REGION.

CLEAR SKIES WILL START TO CLOUD UP AS THE NEXT SYSTEM APPROACHES.
PRECIPITATION LOOKS TO HOLD OFF UNTIL LATER IN THE DAY BUT WE
MIGHT START TO SEE OUR FIRST FLAKES FALL DURING THE
AFTERNOON/EARLY EVENING HOURS.

TEMPERATURES WILL GENERALLY RISE INTO THE UPPER 20S TO LOWER 30S
THROUGH MUCH OF THE REGION, WITH MID TO UPPER 30S ACROSS SOUTHERN
DELAWARE AND ALONG THE COAST.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE MID-LEVEL PATTERN FEATURES THE POLAR VORTEX OVER HUDSON'S
BAY... A RIDGE INVOF THE WEST COAST OF NOAM AND A SOUTHERN STREAM
CUT OFF LOW NEAR BAJA CALIFORNIA...THAT MAY FINALLY EJECTED
NORTHEASTWARD BY THE MIDDLE OF NEXT WEEK. THESE FEATURES WILL
GUIDE S/WV ENERGY THRU A MEAN TROUGH OVER THE EAST CONUS. THIS
TROUGH IS EXPECTED TO BECOME NEGATIVELY TILTED...LEADING TO THE
REDEVELOPMENT OF A CLIPPER SYSTEM INVOF CAPE COD ON FRI...AND WILL
BE FOLLOWED BY S/WV RIDGING FOR A BRIEF TIME OVER THE REGION ON
SUNDAY. MEANWHILE...A PRIMARY S/WV ENTERS THE NORTHERN INTER-
MOUNTAIN WEST ON SATURDAY ACCOMPANIED BY SEVERAL OTHER PIECES OF
ENERGY EXTENDING FROM HUDSON'S BAY TO THE GULF COAST. THE DEGREE
OF PHASING THESE FEATURES UNDERGO AS THEY TRAVERSE THE EAST CONUS
TROUGH...AND REDEVELOPMENT INVOF THE EAST COAST...PRESENTS THE
GREATEST UNCERTAINTY IN THIS FORECAST. AT THE D+5 TIME
FRAME...IT/S TO EARLY TO LOCK ONTO ANY SPECIFICS...BUT THE NAO IS
PROJECTED TO GO FROM NEGATIVE TO POSITIVE WHICH IS TYPICALLY
FAVORABLE FOR EAST COAST CYCLOGENISIS.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...VFR CONDITIONS EXPECTED. CLEAR SKIES WILL CONTINUE
THROUGH THE OVERNIGHT PERIOD. WINDS WILL DIMINISH THIS EVENING,
BECOMING LIGHT AND VARIABLE OVERNIGHT.

THURSDAY...VFR CONDITIONS EXPECTED. SKIES START TO CLOUD UP
DURING THE MORNING IN ADVANCE OF AN APPROACHING WEATHER SYSTEM.
CEILINGS WILL GRADUALLY LOWER THROUGH THE DAY BUT SHOULD REMAIN
VFR THROUGH THE TAF PERIOD. WINDS WILL BE OUT OF THE EAST
SOUTHEAST...BECOMING MORE SOUTHERLY BY AFTERNOON. WIND SPEEDS WILL
GENERALLY BE LIGHT UNTIL THE AFTERNOON AND REMAIN LESS THAN 10
KNOTS.

OUTLOOK...
THURSDAY NIGHT THRU FRIDAY MORNING...MVFR/IFR IN LIGHT SNOW.

FRIDAY AFTERNOON...CONDITIONS IMPROVING TO VFR. MVFR/IFR POSSIBLE
IN SNOW SQUALLS. NW WINDS GUSTING AROUND 30 KT.

FRI NIGHT...VFR WITH GUSTY NW WINDS EXPECTED TO CONTINUE.

SATURDAY...VFR.

SUNDAY AND MONDAY...LIGHT SNOW IS EXPECTED TO OVERSPREAD THE AREA
LATE SUNDAY OR EARLY MONDAY...LOW CONFIDENCE ON TIMING. MVFR/IFR
POSSIBLE IN THE SNOW.

&&

.MARINE...
THE SMALL CRAFT ADVISORY FOR LOWER DELAWARE BAY HAS EXPIRED. THE
SMALL CRAFT ADVISORY ON THE OCEAN IS IN EFFECT THROUGH 1 AM.

WINDS ARE DIMINISHING AS THE PRESSURE GRADIENT WEAKENS ACROSS OUR
AREA. SEAS ARE ALSO STARTING TO DECREASE. EXPECT BOTH WINDS AND
SEAS TO FALL BELOW SMALL CRAFT ADVISORY CRITERIA ON OUR OCEAN
WATERS LATER TONIGHT. LIGHT FREEZING SPRAY WILL REMAIN POSSIBLE
THROUGH TONIGHT.

SUB-ADVISORY CONDITIONS ARE EXPECTED FOR THURSDAY WITH LIGHT
EASTERLY WINDS AND SEAS AROUND 2 TO 3 FEET ON THE OCEAN.

OUTLOOK...
THU NIGHT...WINDS AND SEAS MAY APPROACH SCA THRESHOLDS.

FRI/FRI NIGHT...GALE FORCE WIND GUSTS INCREASINGLY LIKELY.

SAT...GALE CONDITIONS DIMINISHING BACK TO SCA CONDITIONS.

SUN...SUB SCA CONDITIONS EXPECTED.

MON...WINDS AND SEAS MAY APPROACH SCA THRESHOLDS.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ450>455.

&&

$$

SYNOPSIS...FRANCK
NEAR TERM...MEOLA
SHORT TERM...MEOLA
LONG TERM...FRANCK/O'HARA
AVIATION...FRANCK/MEOLA
MARINE...FRANCK/MEOLA






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