FXUS61 KPHI 101620
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1120 AM EST THU DEC 10 2009
.SYNOPSIS...
INTENSE LOW PRESSURE OVER EASTERN CANADA AND HIGH PRESSURE
BUILDING IN FROM THE GREAT PLAINS WILL CAUSE TODAY TO BE COLD AND
BLUSTERY. THE HIGH WILL CONTINUE TO BUILD SLOWLY TO THE EAST AND
FINALLY MAKE IT OVER THE REGION SATURDAY EVENING. A LOW PRESSURE
SYSTEM MOVING BY WELL TO THE SOUTH ON SUNDAY COULD AFFECT THE
AREA. A COLD FRONT SHOULD MOVE THROUGH FROM THE NORTHWEST LATE
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
STRONG LOW PRESSURE WELL TO THE NORTH IN EASTERN CANADA AND STRONG
HIGH PRESSURE BUILDING EAST FROM THE GREAT PLAINS WILL BRING THE
REGION DRY COLD WEATHER TODAY WITH BLUSTERY WEST WINDS. THE 925 MB
WINDS INCREASE TO 35-40 KT THIS MRNG, THEN DECREASE A BIT FOR 18Z
BEFORE REGAINING SOME STRENGTH TO NEAR 40 KT LATE IN THE DAY. SOME
OF THESE WINDS COULD MIX DOWN TO THE GROUND AND DUE TO THIS, I
KEPT THE WIND ADVISORY AS WAS PREVIOUSLY ISSUED. ALSO, WITH WEAK
CYCLONIC FLOW ALOFT AND SOME BLYR MOISTURE, I CARRIED POSSIBLE
FLURRIES NORTH, OTHERWISE, SKIES WILL BE PARTLY SUNNY. THE CLOUDS
SOUTH WILL BE DUE TO HIGH CLOUDS BUT WITH THE LOW SUN ANGLE WE
HAVE THIS TIME OF YEAR, THEY WILL BE MORE EVIDENT. OVER THE
NORTHERN AREAS, STRATOCU WILL BE THE MAIN SOURCE OF CLOUDS. AS THE
DAY PROGRESSES, THE HIGH CLOUDS SHOULD DISSIPATE, BUT SOME OF THE
STRATOCU COULD MAKE IT SOUTH.
TEMPERATURES TODAY WILL GENERALLY BE STEADY AS SHOWN BY MODEL
SOUNDINGS. OVERNIGHT TEMPS WILL KEEP DROPPING UNTIL SUNRISE AND
SOME READINGS AT DAYBREAK MAY BE THE HIGH FOR THE DAY. THE MET
HOURLY TEMPS LOOK MUCH BETTER THAN THE MAV.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
WE WILL REMAIN UNDER WEST TO NW FLOW AS HIGH PRESSURE CONTINUES TO
BUILD OVER THE REGION. DUE TO THIS FLOW PATTERN, SKIES WILL BE
PARTLY CLOUDY NORTH AND MOSTLY CLEAR SOUTH. SOME FLURRIES COULD
ALSO OCCUR OVER THE POCONOS, BUT MEASURABLE IS NOT EXPECTED.
ARCTIC AIR WILL OVERSPREAD THE REGION AS INDICATED BY THE 1000-850
THICKNESSES BELOW 1250 ON FRIDAY. LOWS TONIGHT WILL BE THE COLDEST
OF THE SEASON SO FAR WITH LOWS AROUND 10 NORTH TO THE LOWER 20S
SOUTH. WIND CHILL VALUES WILL BE NEAR 5 BELOW ZERO NORTH TO TEENS
ABOVE SOUTH. DUE TO THE ARCTIC AIRMASS FRIDAY, HIGH TEMPS SHOULD
STAY BELOW FREEZING OVER ALL BUT THE SOUTHERN AREAS WHERE THEY
WILL JUST BARELY GET ABOVE 32.
VERY COLD TEMPERATURES CONTINUE FRIDAY NIGHT ALTHOUGH THEY MIGHT
BE A DEGREE OR TWO HIGHER THAN TONIGHT. ON SATURDAY, THE AIRMASS
MODIFIES ENOUGH SO THE HIGHS GET CLOSER TO NORMAL, ALTHOUGH STILL
A BIT BELOW.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE ACTIVE SUBTROPICAL JET COURTESY OF OUR WEEKLY STRONG RATED EL
NINO CONTINUES TO CAUSE FORECASTING PROBLEMS IN THIS RANGE, ONE
BECAUSE IT IS ACTIVE AND TWO BECAUSE ITS COVERING MORE REAL ESTATE
THAN AVERAGE, THUS THE SHORT WAVES ARE COMING ONSHORE AND MOVING
ACROSS THE SOUTHERN CONUS FASTER THAN AVERAGE GIVING LESS FORECAST
LEAD TIME. LONG TERM FORECAST CONFIDENCE WILL REMAIN LESS THAN
AVERAGE.
CASE IN POINT WITH THIS WEEKEND SYSTEM IN WHICH THE GFS AND ECMWF
ARE CURRENTLY STILL ABOUT 24 HOURS APART IN THE ARRIVAL OF
PRECIPITATION, SUNDAY MORNING VS MONDAY MORNING. EVEN THOUGH THERE
ARE TIMING DIFFERENCES, THERE IS A GENERAL MODEL CONSENSUS OF A
GENTLE WAA PATTERN STARTING TO THE WEST OF THE ARCTIC HIGH WITH A
RELATIVELY WEAK LOW PRESSURE SYSTEM EMERGING OFF THE SOUTHERN MIDDLE
ATLANTIC OR SOUTHEAST COAST. WE DID NOT WANT TO PUSH THE START OF
PCPN CHANCES ALL THE WAY TO SUNDAY NIGHT, BUT FOR NOW REMOVED
MENTION FOR SATURDAY NIGHT.
THE AIR MASS WILL START COLD ENOUGH FOR SNOW, ESPECIALLY THE SOONER
IT STARTS AND THEN ANY REMAINING COLD AIR BY SUNDAY NIGHT/MONDAY
WOULD BE PRETTY MUCH CONFINED TO GROUND LEVEL.
ANOTHER ARCTIC COLD FRONT IS FORECAST TO MOVE THROUGH OUR CWA ABOUT
TUESDAY. THE MODELS HAVE BACKED AWAY FROM A MORE VIGOROUS SOUTHERN
STREAM CONTRIBUTOR TO THIS SYSTEM. GIVEN HOW ACTIVE IT HAS BEEN WE
WILL HAVE TO WATCH THIS SOLUTION IN THE DAYS AHEAD. PRECEDING THIS
FRONT THE AIR MASS FOR MUCH OF OUR CWA SHOULD BE WARM ENOUGH FOR
MAINLY RAIN SHOWERS. WE MENTIONED FLURRIES IN THE NW FLOW BEHIND
THIS FRONT FOR OUR NWRN CWA IN THE ARCTIC AIR MASS. MAX TEMPS ON
WEDNESDAY MIGHT BE TOO HIGH PENDING HOW QUICKLY THIS BLAST ARRIVES.
TEMPS IN THE LONG TERM SHOULD AVERAGE BELOW NORMAL AT BOTH ENDS WITH
POSSIBLY SOME MILDER THAN NORMAL TEMPS ON MONDAY AND TUESDAY. AFTER
THE ARCTIC FRONT MOVES THROUGH THE MEDIUM MODELS ARE FORECASTING THE
CONTINUATION OF A RATHER ROBUST -NAO PATTERN WITH A BLOCK INTO
GREENLAND AND A POLAR VORTEX THAT CAME FROM RUSSIA WITH LOVE TO
REACH THE CANADIAN MARITIMES AT THE END OF NEXT WEEK.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
PRIMARY ISSUE WILL BE THE WINDS FOR THE NEXT SEVERAL DAYS ALTO THEY
WILL BE CONSISTENTLY FROM THE WEST. PUBLIC WIND ADVISORIES ARE IN
EFFECT SO SOME OF THE WIND GUSTS TO 40 KTS. OTHERWISE GOOD VFR
CONDITIONS THROUGH SATURDAY.
OUTLOOK...
STORM SYSTEM MOVING NORTH ALONG THE COAST SUNDAY WILL BRING LOWERING
CIGS/VSBYS WITH CATEGORIES OF IFR BY SUNDAY EVENING.
&&
.MARINE...
YOU WOULD BE HARD-PRESSED TO FIND A GALE FORCE GUST TO 34 KT TODAY
BUT WILL KEEP THE GALE WARNINGS UP SINCE IT ALERTS THOSE PLANNING
TO GO OFFSHORE OR THOSE OFFSHORE PLANNING TO RETURN TO MAKE
DECISIONS. IN ANY EVENT...THE COLDEST AIR BEHIND THE DEEP LOW OF
YESTERDAY IS YET TO ARRIVE BUT WILL DO SO LATE THIS AFTERNOON AND
EVENING AND CONTINUE INTO FRIDAY. THE COLD AIR WILL BRING THE
HIGHER WIND SPEEDS DOWN TO THE SURFACE.
WITH THIS TYPE OF A SET-UP THE LOWER DELAWARE BAY IS MUCH ROUGHER
THAN THE OCEAN SIDE WHICH HAS A SMALLER FETCH FOR THE NEARSHORE
WATERS. AS A RESULT...THE WAVES REPORTED NEARSHORE ARE UNDER 2.5
FEET WHILE IN THE DELAWARE BAY CLOSER TO 6 FEET WITH THE LONGER
FETCH DOWN THE BAY. THE WAVE HEIGHTS WILL NOT CHANGE THROUGH THIS
OFFSHORE WIND EVENT INTO THE WEEKEND.
WHAT WE WILL SEE FOR THE FIRST TIME THIS SEASON IS THE FACTOR OF
THE WIND AND TEMPERATURE AND LOWERING WIND CHILLS. OVERNIGHT
TONIGHT AT BUOY 44009 THE WIND CHILL WILL BE IN THE LOWER 20S.
CLOSER TO SHORE WHERE THE LAND TEMPERATURES WILL BE LOWER IT'LL
PROBABLY BE IN THE TEENS. GO TO THE NATIONAL DATA BUOY CENTERS WEB
SITE AND CALL UP THE PARTICULAR BUOY IN MIND AND YOU'LL SEE WHAT
THE WCHILL TEMPERATURE IS.
AT 11 AM TODAY...BUOY 44009 HAS A WIND FROM THE WEST(270 DEGREES)
AT 16 TO 19 KTS WITH A 5 FT SEA EVERY 6 SECONDS. THE TEXAS TOWER
BUOY 44066 IS REPORTING THE SAME DIRECTION WITH 23 TO 29 KNOTS AND
A 13 FT SEA EVERY 10 SECONDS. WATER TEMPERATURES ARE 53 AT 44009
AND 58 AT TT4.
THE OFFSHORE WINDS AND COLD TEMPERATURES WILL CONTINUE INTO
SATURDAY WITH A TURN TO WARMER CONDITIONS ON SUNDAY BUT AT THE
EXPENSE OF DETERIORATING WEATHER AND A WEAK LOW PRESSURE MOVING
NORTH ALONG THE COAST.
GALES ARE UP FOR THE CANYONS OFF OUR COAST UNTIL SATURDAY. MAKE
SURE YOU CHECK THE OCEAN PREDICTIONS WEB SITE FOR DETAILS.
&&
.HYDROLOGY...
PLEASE CONSULT THE LATEST FLS/FLW PRODUCTS OR CHECK OUT THE AHPS
PAGES ON THE WEB FOR THE LATEST INFORMATION CONCERNING LINGERING
FLOODING FROM WEDNESDAY/S RAIN.
&&
.TIDES/COASTAL FLOODING...
THE WIND SET UP IS IDEAL FOR LOWERING TIDE LEVEL. SO ANYONE NAVIGATING
THE INTERCOASTAL OR FOR BIGGER SHIPS ROUNDING THE POINTS...THE
TIDES MAY BE ABOUT 1.5 FT BELOW MEAN LOWER LOW WATER ESPECIALLY
GETTING INTO FRIDAY. WINDS PLAY A MAJOR ROLE WITH THE TIDES...AT
THIS TIME ON WEDNESDAY SANDY HOOK WAS NEARLY 4 FT ABOVE NORMAL AND
NOW WE'RE LOOKING AT A NEAR BLOWOUT TIDE. WE BEGIN ISSUING STATES
FOR NEGATIVE DEPARTURES WHEN THE TIDES REACH 2.0 BELOW MEAN LOWER
LOW WATER.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR PAZ054-055-
060>062-067>071.
NJ...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NJZ001-007>010-
012>027.
DE...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR DEZ001>004.
MD...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR MDZ008-012-015-
019-020.
MARINE...GALE WARNING UNTIL 2 PM EST FRIDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...STAUBER
SHORT TERM...STAUBER
LONG TERM...GORSE
AVIATION...EBERWINE/RPW
MARINE...EBERWINE/RPW
HYDROLOGY...
TIDES/COASTAL FLOODING...EBERWINE
