NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Jan 15, 3:48 PM EST, 8 hours 12 minutes earlier.
Area forecast discussion, Jan 15, 3:48 PM EST, 8 hours 12 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
348 PM EST THU JAN 15 2009
.SYNOPSIS...
A TRUE ARCTIC AIR MASS WILL CONTINUE TO SETTLE INTO OUR AREA TONIGHT
AND LINGER INTO THE WEEKEND AS AN EXPANSIVE AREA OF HIGH PRESSURE
MOVES FROM THE CENTRAL PLAINS TO THE MID ATLANTIC COAST. THIS AREA
OF HIGH PRESSURE WILL THEN MOVE QUICKLY TO OUR EAST AND NORTHEAST
SATURDAY AS ANOTHER STORM SYSTEM APPROACHES. A PORTION OF THIS
STORM SYSTEM IS FORECAST TO SLIDE ACROSS OUR AREA SATURDAY NIGHT
INTO SUNDAY, THEN THE MAIN STORM TRACKS TO OUR NORTHWEST ON
SUNDAY. AN ASSOCIATED COLD FRONT ARRIVES SUNDAY NIGHT, HOWEVER A
NEW STORM SYSTEM MAY DEVELOP OFF THE MID ATLANTIC COAST MONDAY AND
TUESDAY. ANOTHER POSSIBLE CLIPPER SYSTEM ARRIVES TUESDAY INTO
WEDNESDAY. HIGH PRESSURE THEN SLIDES INTO OUR AREA LATER WEDNESDAY,
THEN TO OUR SOUTH AND EAST DURING THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AN 18Z SURFACE ANALYSIS PLACED LOW PRESSURE SOUTH OF CAPE COD WITH A
TROUGH EXTENDED WESTWARD THROUGH NORTHERN NEW JERSEY TO THE EASTERN
GREAT LAKES. MEANWHILE, A LARGE HIGH PRESSURE SYSTEM WAS PARKED OVER
THE CENTRAL PLAINS. AN UPPER AIR ANALYSIS PLACED THE MIDLEVEL TROUGH
AXIS FROM THE CENTRAL GREAT LAKES TO THE LOWER MISSISSIPPI VALLEY,
WITH ONE SHORT WAVE MOVING THROUGH THE NORTHERN MID ATLANTIC AND
ANOTHER ONE IN THE UPPER OHIO VALLEY. THAT LATTER CAN BE MORE
CLEARLY SEEN ON THE WATER VAPOR IMAGERY. AN EXPANSIVE CYCLONICALLY
CURVED 300 MB JET WAS FROM THE CANADIAN MARITIMES TO THE MID
ATLANTIC, THEN BACK INTO THE NORTHERN HIGH PLAINS.
AN AREA OF SNOW SHOWERS HAS BEEN MOVING THROUGH MOST OF OUR REGION
THIS AFTERNOON, AND THIS APPEARS TO BE ALONG THE LEADING EDGE OF THE
EVEN COLDER AND DRIER AIR. SOME SHORT WAVE ENERGY SCOOTING ACROSS
COMBINED WITH SOME LOW-LEVEL INSTABILITY IS ALSO HELPING TO
GENERATE THE SNOW SHOWERS. WE ARE NOT ANTICIPATING MUCH FROM THESE
INTO THE EVENING AS THEY ARE QUICK MOVING AND WILL FADE AWAY. THEY
HAVE GREATLY REDUCED THE LOCAL VISIBILITY THOUGH FOR A BRIEF TIME
AS WE OBSERVED A BURST OF SNOW HERE AT THE OFFICE AT ABOUT 1950Z.
THE CLIPPER SYSTEM IS TO OUR EAST, HOWEVER VISIBLE SATELLITE
IMAGERY SHOWS NICELY WHAT LOOKS LIKE A COMMA HEAD JUST EAST OF THE
JERSEY SHORE /SEE THE POST MORTEM BELOW REGARDING THIS SYSTEM/. AS
THIS CLIPPER CONTINUES TO SLIDE FARTHER AWAY TONIGHT, OUR WEATHER
WILL BE DOMINATED BY A BITTERLY COLD AIR MASS SETTLING IN. THE
HIGH RESOLUTION WRF ALONG WITH OUR INHOUSE WRF INDICATES THAT SOME
NARROW LAKE EFFECT SNOW STREAMERS MAY MAKE INTO OUR CWA TONIGHT.
THE PLACEMENT IS GENERALLY AGREED UPON AS BEING UP ACROSS THE
NORTHERN COUNTIES AS A POSSIBLE STREAMER MAY CONNECT TO LAKE HURON
AS A SHORT WAVE MOVES THROUGH. THESE FEATURES ARE DIFFICULT TO
FORECAST AND PINPOINT, HOWEVER WILL CARRY AT LEAST ISOLATED SNOW
SHOWERS ACROSS THE FAR NORTHWEST ZONES TONIGHT WITH SOME FLURRIES
BORDERING THIS. THE AIR MASS IS VERY COLD AND DRY THEREFORE ANY
SNOW WILL BE RATHER FLUFFY /LOCAL ACCUMULATIONS OF A COATING TO
PERHAPS UP TO AN INCH POSSIBLE/. ELSEWHERE, THE STRATOCUMULUS
SHOULD TEND TO THIN OUT WITH TIME AS DRIER AIR INFILTRATES THE
AREA AND WE LOSE THE EFFECTS OF THE DAYTIME HEATING.
THE NORTHWESTERLY WINDS SHOULD SETTLE DOWN SOME THROUGH THE NIGHT,
HOWEVER WE ARE STILL EXPECTING A BREEZE TO HOLD UP. WITH THE VERY
COLD AMBIENT AIR TEMPERATURES, IT WILL NOT TAKE MUCH WIND TO GET
WIND CHILL VALUES TO ZERO OR BELOW. WE HELD WINDS UP A LITTLE MORE
THAN MOST OF THE MODEL GUIDANCE SUGGESTS, MAINLY BASED ON THE
FORECAST SOUNDINGS LOW-LEVEL PROFILES. FOR TEMPERATURES, WE
DECIDED TO UNDERCUT THE MOS VALUES FOR MANY AREAS GIVEN THE SCOPE
OF THIS AIR MASS. THESE VALUES COMBINED WITH THE WIND WILL PRODUCE
VERY COLD WIND CHILLS TONIGHT. THE PHILADELPHIA TO TRENTON
CORRIDOR ON EAST AND SOUTHWARD, THE CRITERIA FOR A WIND CHILL
ADVISORY IS -10F, ELSEWHERE IT IS -15F. SOME SPOTS IN THE -10F
CRITERIA MAY NEAR THIS OVERNIGHT, HOWEVER THE LATEST NUMBERS ARE
NOT WIDESPREAD TO THAT VALUE. WE ARE HOWEVER REACHING THE CRITERIA
IN CARBON AND MONROE COUNTIES, THEREFORE WE WILL ISSUE A WIND
CHILL ADVISORY THERE. ACROSS THE REST OF THE CWA, IT WILL BE
BITTERLY COLD AND WE WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK /HWO/ AND THE WORDED FORECASTS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
A BITTERLY COLD DAY IS IN STORE FRIDAY AS WE WILL BE UNDER A
NORTHWESTERLY FLOW. A LARGE HIGH PRESSURE SYSTEM WILL BE MOVING INTO
THE UPPER OHIO VALLEY REGION DURING FRIDAY, HOWEVER A TIGHTENED
PRESSURE GRADIENT WILL REMAIN ACROSS OUR REGION. THIS WILL RESULT IN
BLUSTERY CONDITIONS. SOME SHORT WAVE ENERGY TRACKING WITHIN THE
NORTHWESTERLY UPPER-LEVEL FLOW WILL MOVE ACROSS OUR AREA. THE
MAJORITY OF THE ATMOSPHERIC PROFILES ARE RATHER DRY, HOWEVER THERE
IS SOME LOW-LEVEL INSTABILITY FORECAST DUE TO THE VERY STEEP
LOW-LEVEL LAPSE RATES. THERE DOES NOT APPEAR TO BE ANYTHING REALLY
TO FOCUS LIFT ON FRIDAY, THEREFORE WE WILL LEAVE THE MAJORITY OF THE
CWA PRECIPITATION-FREE. WITH SOME POSSIBLE LAKE EFFECT STREAMERS
ARRIVING INTO NORTHEASTERN PENNSYLVANIA, WE WILL CARRY LOW CHC POPS
ACROSS OUR FAR NORTHWESTERN COUNTIES. SINCE THE AIR IS VERY COLD,
ANY DEEPER STRATOCUMULUS CLOUDS ON FRIDAY MAY BE ABLE TO PRODUCE
SOME FLURRIES OR A BRIEF SNOW SHOWER. THE COVERAGE OF THIS SHOULD
BE RATHER SMALL, THEREFORE WE WILL NOT INCLUDE ATTM.
IT WILL BE DANGEROUSLY COLD FRIDAY NIGHT AS HIGH PRESSURE EDGES
CLOSER. THE CORE OF THE COLD AIR LOOKS TO SLIDE ACROSS OUR AREA
FRIDAY EVENING. WE MAY STILL BE ABLE TO HOLD ONTO SOME WIND FRIDAY
NIGHT, THEREFORE WIND CHILL VALUES WILL BE RATHER LOW AND AN
ADVISORY MAY BE NEEDED /ESPECIALLY FOR THE FAR NORTHWEST/. WE WILL
MENTION THIS IN THE HWO AS WELL. WE THEN TURN OUR ATTENTION TO
THE WEST AS A SIGNIFICANT SHORT WAVE DIVES SOUTHEASTWARD FROM
CENTRAL CANADA INTO THE MIDWEST FRIDAY. THIS WILL DRIVE YET
ANOTHER CLIPPER SYSTEM, HOWEVER THIS ONE APPEARS TO BE TRACKING
FARTHER NORTH, GIVEN THE UPPER-LEVEL FLOW PATTERN THAT IS IN
PLACE. WE WILL GRADUALLY SEE AN INCREASE IN CLOUDS ON SATURDAY AS
WAA AND ISENTROPIC UPGLIDE INCREASES TO OUR WEST. THE PLACEMENT OF
THE ELEVATED THERMAL GRADIENT AND FRONTOGENETIC FORCING LOOKS TO
BE ACROSS OUR NORTHWESTERN ZONES SATURDAY NIGHT. AS THE MOISTURE
DEEPENS, WE SHOULD SEE A PERIOD OF MAINLY LIGHT SNOW ARRIVE LATER
SATURDAY NIGHT. THIS SETUP LOOKS SIMILAR TO OUR RECENT CLIPPER
DESPITE THE STORM TRACK LOOKING TO BE FARTHER NORTH. PERHAPS THIS
CLIPPER MAY END UP TRACKING FURTHER SOUTH AND WE WILL SEE AS THE
DETAILS BECOME MORE CLEAR. SINCE THE MODELS ARE IN GOOD AGREEMENT
WITH THE QPF AXIS ACROSS THE FAR NORTH SATURDAY NIGHT, WE INCLUDED
LOW END LIKELY POPS THEN TAPERED OFF TO CHC SOUTHWARD.
AS FOR TEMPERATURES, WE GENERALLY USED A BLEND OF CONTINUITY AND
MOSGUIDE.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE UPPER-LEVEL PATTERN DURING MOST OF THIS TIME FRAME WILL BE SUCH
THAT A RIDGE IS MAINTAINED IN THE WEST WHILE A TROUGH IS IN THE
EAST. THERE CONTINUES TO BE SIGNALS THOUGH THAT THE UPSTREAM
RIDGING BEGINS TO BREAK DOWN TOWARD THE END OF THIS PERIOD, ALLOWING
THE EASTERN TROUGH TO BEGIN LIFTING OUT WITH A NOTED MODERATION IN
TEMPERATURES AS A RESULT. THE GFS ENSEMBLE MEMBERS APPEAR TO HAVE
SETTLED DOWN AS THEY MAINLY AGREE WITH THE SYNOPTIC PATTERN THROUGH
WEDNESDAY WITH THE UPPER-LEVEL TROUGH REMAINING IN THE EAST, HOWEVER
THERE IS SOME DIFFERENCES NOTED IN WHERE THE TROUGH AXIS IS ON
WEDNESDAY. WITH SUCH AN AMPLIFIED UPPER-LEVEL PATTERN, THERE WILL
LIKELY BE TIMING ISSUES REGARDING THE SHORT WAVE ENERGY THAT OVER
TOPS THE WESTERN RIDGE AND THEN DROPS DOWN INTO THE EASTERN TROUGH.
THE TIMING AND STRENGTH OF THESE FEATURES WILL ULTIMATELY DRIVE OUR
MORE SENSITIVE WEATHER. A VERY LARGE DEAL OF UNCERTAINTY REMAINS IN
THE EASTERN PACIFIC PATTERN EVOLUTION AS THE ECMWF KEEPS ITS IDEA OF
A STRONG CLOSED MIDLEVEL LOW APPROACHING THE WEST COAST WHILE THE
GFS SERIES KEEPS ITS NORTHERN STREAM FEATURE THE DOMINANT ONE. THIS
WILL ALL HAVE DOWNSTREAM AFFECTS. HPC UTILIZED AN EVEN BLEND OF
THE ECMWF AND GFS, WHICH WOULD YIELD A MEAN SOLUTION ESPECIALLY
FOR THE EASTERN PACIFIC/WESTERN UNITED STATES DIFFICULTIES. WE
FOLLOWED GUIDANCE FROM HPC, HOWEVER WE DID MAKE SOME ADJUSTMENTS
FOR LOCAL AFFECTS AND AFTER COLLABORATION WITH OUR NEIGHBORING
OFFICES. GIVEN ALL OF THIS, HERE ARE SOME DETAILS.
THE CORE OF THE ARCTIC AIR WILL BE SLIDING FROM NORTHERN NEW ENGLAND
ON NORTHWARD SUNDAY AS HIGH PRESSURE MOVES TO THAT REGION. THIS WILL
ALLOW A STORM SYSTEM /FROM THE SHORT TERM/ TO MOVE ACROSS OUR AREA
DURING SUNDAY. THE ORIENTATION OF THIS ENERGY LOOKS TO DRIVE THE
SURFACE LOW TO OUR NORTHWEST, HOWEVER THERE APPEARS TO BE A COLD AIR
DAMMING SIGNATURE INTO OUR AREA AS A DEVELOPING WARM FRONT MAY STAY
TO OUR SOUTH. AS A RESULT, OUR AREA WILL BE UNDER A WAA/ISENTROPIC
UPGLIDE REGIME/ FOR AWHILE SUNDAY. AS WITH THIS TIME FRAME, THE
DETAILS ARE ALWAYS IN QUESTION AND WE ARE WONDERING IF THE
AFOREMENTIONED SURFACE HIGH WILL BE EXACTLY WHERE IT IS CURRENTLY
PLACED OR EVEN MOVING. REGARDLESS, COLD AIR IS EXPECTED TO BE IN
PLACE IN ADVANCE OF THIS SYSTEM. THIS ENTIRE SETUP ALMOST LOOKS
SIMILAR TO THE CLIPPER WE JUST DEALT WITH AS THE MAIN AXIS OF
FRONTOGENETIC FORCING IS ACROSS OUR NORTHERN ZONES. THE MODELS ARE
IN GOOD AGREEMENT WITH THIS PLACEMENT, THEREFORE WILL RAISE POPS
UP ACROSS THE NORTH TO LOW END LIKELY FOR NOW SUNDAY MORNING, THEN
TAPER OFF SOUTHWARD TO CHC AND LESS. WE ARE STILL EXPECTING THE AIR
TEMPERATURES TO MODERATE ON SUNDAY AS THIS SYSTEM MOVES THROUGH,
WITH AREAS FROM ABOUT INTERSTATE 95 SOUTH AND EAST GETTING TO
FREEZING OR ABOVE IN THE AFTERNOON. WE WILL CONTINUE TO CARRY SNOW
AS THE PRECIPITATION TYPE AS THE ATMOSPHERIC COLUMN IS PLENTY
COLD, HOWEVER MODIFYING BOUNDARY LAYER TEMPERATURES ACROSS FAR
SOUTHERN DELAWARE COULD ALLOW FOR SOME LIQUID TO MIX IN. THE
PRECIPITATION ON SUNDAY DOES NOT LOOK LIKE IT WILL BE THAT
ORGANIZED SO WE WILL CARRY SHOWERS AS THE TERMINOLOGY. A SURFACE
LOW MAY REDEVELOP TO OUR EAST HOWEVER, IT MAY BE TO FAR TO OUR
NORTHEAST AS UPSTREAM ENERGY IS FORECAST TO BE DIGGING INTO THE
OHIO VALLEY LATE SUNDAY INTO MONDAY. WE MAY NOT HAVE MUCH
PRECIPITATION AROUND SUNDAY NIGHT THROUGH MONDAY, HOWEVER THE
UPPER-LEVEL TROUGH WILL BE OVERHEAD WITH EMBEDDED SHORT WAVES
MOVING THROUGH. THIS COULD ALLOW FOR SOME SHOWERS OR FLURRIES
THERE AND WILL CARRY LOW CHC TO SLIGHT CHC POPS FOR THIS GIVEN THE
UNCERTAINTY.
DEPENDING ON THE ORIENTATION OF THE UPPER-LEVEL TROUGH AND EMBEDDED
SHORT WAVE ENERGY, A STORM MAY GET GOING OFF THE COAST ON TUESDAY.
FOR NOW WE WILL OPT TO PLACE IT FAR ENOUGH TO OUR EAST FOR NOT
MUCH OF AN IMPACT HOWEVER GIVEN THE PATTERN, WE WILL HAVE TO WATCH
THE EVOLUTION. HIGH PRESSURE IS THEN FORECAST TO BE APPROACHING
FROM THE WEST WEDNESDAY, THEN SLIDE TO OUR SOUTH AND EAST ON
THURSDAY. THE ADVERTISED UPPER-LEVEL PATTERN SHIFT AS WELL WITH A
RETURN SURFACE FLOW WOULD ALLOW OUR TEMPERATURES TO MODIFY
WEDNESDAY AND ESPECIALLY THURSDAY. AS THIS OCCURS, PERHAPS SOME
SNOW SHOWERS ACROSS THE NORTHWESTERN ZONES WITH THE WAA, HOWEVER
DUE TO THE UNCERTAINTY ON THE STRENGTH AND PLACEMENT OF THIS, WE
WILL KEEP THURSDAY DRY FOR NOW.
THAT IS ALL FOR NOW. THANKS TO THE SURROUNDING OFFICES/HPC FOR THE
COLLABORATION TODAY. HAVE A GOOD ONE
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
SEEMS LIKE ITS NEVER GOING TO END. STEADY STREAM OF COLD AIR AND
GUSTY SURFACE WINDS IS SQUEEZING OUT THE LAST OF THE FLURRIES THIS
AFTERNOON. THE LOW HAS PULLED OFFSHORE AND IS SLOWLY PULLING THE
SNOW AWAY WITH IT. THE BACK EDGE IS ALMOST THROUGH EASTERN PA AND
INTO THE OCEAN. CLOUD TOPS ARENT VERY HIGH, SOMEWHERE AROUND 8 OR
9,000 FT AND THE SNOW IS NOT COMING DOWN HARD ENOUGH TO THREATEN THE
VFR CONDITIONS. DEW POINTS ARE INTO THE LOW TEENS AND SINGLE DIGITS
SO MOST OF THE SNOW IS EVAPORATING BEFORE REACHING THE GROUND. WIND
WILL FAVOR APPROACHES TO THE WEST AND NORTHWEST. WIND GUSTS MOST
AREAS EXCEPT NORTH OF TRENTON ARE IN THE 20S TO NEAR 30 KNOTS.
CENTRAL AND NORTH JERSEY IN THE 10 TO 15 KT RANGE. THIS SHOULD
INCREASE AS THE LOW MOVES FARTHER OFFSHORE AND COLD AIR WORKS DOWN
TO THE SURFACE. OTHERWISE...TEMPERATURES FOR THE NEXT 5 DAYS ARE
GOING TO BE BELOW FREEZING AT RDG AND ABE...AND AT PHL...PNE AND TTN
BELOW FREEZING EXCEPT FOR SUN/MON/TUE WHEN THE MID 30S ARE FORECAST.
THE STRATOCU ACROSS THE TRACON ARE GOING TO BE AROUND UNTIL SUNSET OR
SO THEN GRADUALLY DISSIPATE. WELL HAVE GOOD VFR WEATHER FOR FRIDAY
AND HALF OF SATURDAY. YOU GUESSED IT...ANOTHER LOW WILL APPROACH
SUNDAY EVENING WITH LIGHT SNOW INTO SOUTHEAST PA AND NORTH. RDG AND
ABE MAY BE ON THE EDGE OF MVFR/IFR WX BUT OTHERS TO THE SOUTH WILL
BE VFR UNTIL SUNDAY NIGHT.
OUTLOOK...
THE LOW MOVES OFFSHORE MONDAY AFTERNOON WITH A STIFF NORTHERLY
GRADIENT AS HIGH PRESSURE NOSES INTO THE REGION. SURFACE LOW OVER
THE GREAT LAKES WILL APPROACH FROM THE NORTHWEST BUT WILL WEAKEN AS
IT REACHED THE NORTHEAST.
FOR MORE COMPREHENSIVE BROADER OVERVIEW OF THE WEATHER WITH THE
QUICKLY CHANGING PATTERNS PLEASE VISIT WWW.AVIATIONWEATHER.GOV
&&
.MARINE...
SMALL CRAFT ADVISORY WILL REMAIN UP ON THE DELAWARE BAY OCEAN UNTIL
SUNUP ON FRIDAY. LOW PRESSURE WILL BE PULLING AWAY BUT BRINING
COLDER AIR AND GUSTY WINDS TO THE COASTAL WATERS. BUOY 44009(STILL
WITHOUT WIND SPEED AND DIRECTION)IS REPORTING SEAS OF SEVEN FEET
EVERY SIX SECONDS. WAVES IN THE DELAWARE BAY ARE 2.5 TO 3 FT WITH
GUSTY WINDS TO 25 KNOTS.
HIGH PRESSURE WILL REACH THE COASTAL WATERS FRIDAY MORNING AND WINDS
WILL DIMINISH. THE AIR IS PRETTY COLD ON THE WATERS AND WILL BE
KEEPING UP THE FREEZING SPRAY NOTICE. BY DAYBREAK NEARSHORE
TEMPERATURES WILL BE AROUND 10 DEGREES AND IN THE MID 20S FARTHER
OFFSHORE. HIGH PRESSURE WILL MOVE OFFSHORE SUNDAY EVENING AS THE
NEXT LOW PRESSURE DROPS SOUTH OUT OF THE GREAT LAKES AND INTO
PENNSYLVANIA SUNDAY EVENING. THIS LOW WILL WEAKEN AS IT MOVES EAST
THEN INTENSIFY AGAIN OVER THE WATERS MONDAY AFTERNOON. ONCE AGAIN A
SURGE OF COLD AIR WILL SWEEP FROM THE LAND TO THE WATERS AND WINDS
WILL BECOME GUSTY. HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY
AFTERNOON BUT STILL ANOTHER LOW WILL APPROACH BUT IT TOO WILL
WEAKEN.
&&
.POST MORTEM /CLIPPER SYSTEM/...
AN INTERESTING SCENARIO UNFOLDED THIS MORNING AS OUR CLIPPER
SYSTEM WAS RATHER DISORGANIZED LAST NIGHT. THE LOWER LEVEL
FRONTOGENETIC FORCING WAS RATHER WEAK AND NOT REAL ORGANIZED
ACROSS THE NORTH, WHICH RESULTED IN LESS QPF. HOWEVER, AS THE
CLIPPER TRACKED ACROSS THE DELMARVA EARLY THIS MORNING, IR
SATELLITE IMAGERY SHOWED A RAPID COOLING OF THE CLOUD TOPS IN A
NARROW CORRIDOR FROM NORTHERN VIRGINIA TO THE NEW YORK CITY AREA.
THIS WAS IN RESPONSE TO AN UPPER-LEVEL JET STREAK, WHICH ENHANCED
THE UPPER-LEVEL DIVERGENCE. THIS IN COMBINATION WITH AN AREA OF
FOCUSED FRONTOGENETIC FORCING AROUND 800 MB, RESULTING IN A RAPID
EXPANSION OF THE SNOW SHIELD MOSTLY ACROSS CENTRAL AND NORTHERN
NEW JERSEY. THIS FEATURE WAS TRANSIENT THEREFORE THE ENHANCEMENT
WAS RATHER SHORT IN DURATION, HOWEVER MODERATE TO HEAVY SNOW
OCCURRED FOR A TIME CREATING HAZARDOUS TRAVEL CONDITIONS. THE
DELAYED ORGANIZATION OF THE BETTER DYNAMICS KEPT THE QPF LOWER
ACROSS NORTHEASTERN PENNSYLVANIA INTO NORTHWESTERN NEW JERSEY,
ALTHOUGH SOME ACCUMULATING SNOW DID OCCUR. CLIPPERS CAN CERTAINLY
BE RATHER INTERESTING, ESPECIALLY WHEN MESOSCALE PROCESSES GET
INVOLVED.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 12 PM EST FRIDAY
FOR PAZ054-055.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ430-431-
450>455.
FREEZING SPRAY ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ430-431-
450>455.
&&
SYNOPSIS...GORSE
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...GORSE/HPC
AVIATION...EBERWINE
MARINE...EBERWINE