Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 011713
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
113 PM EDT WED OCT 1 2014

.SYNOPSIS...
LOW PRESSURE WILL REDEVELOP OFF THE NEW ENGLAND COAST THROUGH
THURSDAY AS HIGH PRESSURE OVER EASTERN CANADA BUILDS IN FROM THE
NORTHEAST. A STRONG LOW PRESSURE SYSTEM OVER THE CENTRAL UNITED
STATES WILL MOVE NORTHEASTWARD INTO ONTARIO BY FRIDAY AND ITS
ASSOCIATED STRONG COLD FRONT WILL MOVE THROUGH THE REGION FRIDAY
NIGHT INTO SATURDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE
DEPARTING FRONT. ANOTHER COLD FRONT WILL CROSS THE REGION AROUND
MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NEXT ESTF UPDATE WE ARE GOING TO CONTINUE MINIMAL POPS MAINLY
AROUND THE EDGES OF OUR CWA. THERE ARE SHOWERS BOTH WEST AND
NORTHEAST OF OUR AREA. THE FORMER SHOULD PASS MOSTLY TO OUR WEST,
WHILE THE LATTER IS STRUGGLING TO ARRIVE IN NORTHERN NJ. CCL BASED
CU ARE FORMING, SO NO BIG CHANGES TO OTHER PARAMETERS NEEDED.

UPPER LOW CROSSING PA/NJ TODAY WITH MOIST CYCLONIC FLOW.
OVERCAST SKIES THIS MORNING SHOULD BRIGHTEN OR THIN A BIT THIS
AFTERNOON TO REVEAL A LITTLE SS.

TEMPS/WINDS/DEWS ARE A 50 50 BLEND OF THE 100Z/1 NAM/GFS MOS.  .

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THERE MAY BE EVENING PARTIAL CLEARING BEFORE BL RH SATURATES AND
DEVELOPS LOWS CLOUDS AND POSSIBLY PATCHY FOG.

GFS MOS TEMPS LOOK FAR TOO COLD SINCE THE LOW PRESSURE SYSTEM IS FAR
TO THE EAST AND THE CAA IS WEAK. USED THE NAM MOS TEMPS FOR LOWS WHICH
ARE SEVERAL DEGREES WARMER THAN THE GFS MOS. EVEN THESE WERE RAISED
A DEGREE OR TWO.

DEWS WERE NAM MOS.

WINDS WERE A 50 50 BLEND OF THE GFS/NAM MOS

POPS WERE BLENDED GFS/NAM MOS AND LOWERED IN THE SW PORTION OF THE FCST
AREA USING THE 21Z/30 SREF.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AN AREA OF HIGH PRES OVER THE CAN MARITIMES WILL NOSE WWD OVER THE
AREA ON THU AND EXPECT A DRY DAY BUT ABUNDANT CLOUDINESS AS ELY
FLOW WILL PERSIST. THIS HIGH WILL REMAIN IN PLACE FOR THU NIGHT
INTO ERLY FRI WITH LOW PRES WELL OFF THE CST OF NEW ENG.

ATTN THEN TURNS TO THE CNTRL CONUS WHERE A POTENT LOW PRES SYS WILL
TAKE SHAPE BEGINNING THU NIGHT. THIS LOW WILL MOVE NNEWD AND
STRENGTHEN AS IT MOVES INTO OR TOWARD ONTARIO ON FRI.

THE MDLS ALL AGREE ON THE FACT THAT THIS LOW DEVELOPS AND MOVES
INTO OR TOWARD  ONTARIO DURG THIS TIME FRAME, THEY DIFFER A BIT
ON THE DETAILS, AS SHOULD BE EXPECTED. THE GFS, NAM/WRF AND CMC
HAVE A SINGLE LOW STRUCTURE AND BRING THE LOW INTO ONTARIO BY
03/18Z. ON THE OTHER HAND, THE ECMWF HAS A DOUBLE LOW STRUCTURE AT
03/18Z AND IS SIGNIFICANTLY WEAKER AT THIS TIME FRAME (BY ABOUT 10
MB) THAN ANY OTHER MDL.

IT THEN IS INTERESTING THAT BY 78 AND 84 HRS THE ECMWF MDL HAS THE
STRONGEST SOLN WITH THE LOW, BUT IT IS FURTHER S AND E WITH THE
LOW CENTER THAN THE OTHER MDLS.

THE CDFNT ASSOCD WITH THIS LOW WILL BEGIN MOVG EWD AND THERE CUD BE
SOME PRECIP IN WRN AREAS BY SUNSET FRI, THOUGH CONFIDENCE IS LOW.

PRECIP CHCS WILL INCREASE FROM W TO E FRI NIGHT AND THERE ARE
TIMING DIFFS WITH THE MDLS AS WELL. THE GFS AND NAM/WRF GENLY KEEP
THE HEAVIEST PRECIP W OF THE I-95 CORRIDOR THRU DAYBREAK SAT WHILE
THE ECMWF AND CMC ARE FURTHER E. THE GFS THEN BRINGS THE HEAVIER
PRECIP THRU DURG THE MRNG HOURS WHILE THE ECMWF IS ABOUT 6 HOURS
FASTER. THEN PRECIP ENDS FROM SW TO NE DURG THE DAY BEHIND THE CFP
AS A WSHFT FROM E TO WNW BRINGS IN DRIER AIR. THERE IS SILL ENOUGH
UNCERTAINTY IN THE MDLS TO KEEP CONFIDENCE LWR THAN AVERAGE. THE
ECMWF IS OFTEN TOO SLOW WITH FRONTAL TIMING, SO ITS INTERESTING
THAT IT IS THE FASTER SOLN HERE.

ONE NOTICEABLE TREND IN THE 01/00 GUID IS IMPROVEMENT IN THE
SECOND HALF OF SAT, SO HAVE LOWERED POPS DURG THIS TIME FOR THIS
FCST ISSUANCE.

WITH THAT SAID, HIGH PRES MOVES IN BEHIND CFP AND SAT NIGHT THRU
MON LOOK DRY.

ANOTHER WK CDFNT WILL CROSS THE REGION ON MON, BUT ATTM NOT ENOUGH
CONFIDENCE TO PUT IN POOPS AS THE ECMWF IS DRY WHILE THE GFS HAS
SOME LOW POPS.

ON TUE, THERE CUD BE SOME ADDITIONAL PRECIP, WHICH THE MDLS
DEVELOP DIFFERENTLY. THE ECMWF TRIES TO DEVELOP SOME FROM AN AREA OF
LOW PRES WHICH TAKES SHAPE FROM SOME SRN STREAM ENERGY OVER THE
SERN STATES AND MOVES NEWD. THE GFS HAS SOME NRN STREAM AND SRN
STREAM ENERGY AND PSBLY ANOTHER WK FROPA. AGAIN, FOR NOW WILL JUST
CARRY SOME LOW POPS.

TEMPS WILL GENLY AVERAGE NR NRML, EXCEPT FOR SUN IN THE COLD
ADVECTION BEHIND THE STRONG FROPA, WHERE TEMPS WILL AVERAGE MUCH
BELOW NRML.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

18Z TAFS WILL CONTINUE THE IDEA OF SOME VFR CONDITIONS THIS
AFTERNOON, BUT THEN PREDOMINATELY MVFR TONIGHT INTO THURSDAY
MORNING.

THIS AFTERNOON INTO EARLY EVENING, MAINLY MVFR CIGS AT COASTAL
AIRPORTS AND TERMINALS, BORDERLINE MVFR/VFR CIGS FOR THE I95
CORRIDOR AND HIGHER TERRAIN AIRPORTS AND TERMINALS AND
PREDOMINATELY VFR CIGS AT KRDG AND KABE. WINDS SHOULD BE
NORTHEAST AT 5 TO 10 KNOTS.

TONIGHT PREDICTING A MVFR CIG TO REFORM AT ALL AIRPORTS AND
TERMINALS, CLOSEST TO IFR LEVELS AT THE COAST. BECAUSE OF THE
PREDICTED CIG, WE DID NOT FORECAST THAT MUCH FOG AND MAINLY AT
THE MORE RURAL TERMINALS. WINDS SHOULD BE LIGHT FROM THE NORTH.

ON THURSDAY WE ARE REVERSING THE PROCESS WITH A SLIGHTLY SLOWER
IMPROVEMENT TO VFR CIGS AS MOISTURE FROM NEW ENGLAND AT THE MVFR
LEVEL CONTINUES TO MOVE INTO THE REGION. WINDS SHOULD BE SLIGHTLY
MORE FROM THE NORTH THAN NORTHEAST AT SPEEDS OF AROUND 10 KNOTS.


OUTLOOK...
THU AFTERNOON...VFR. MDT TO HIGH CONFIDENCE.

FRI..VFR ERLY. PSBL MVFR W LATE. RAIN CHCS LATE W. MDT CONFIDENCE.

FRI NIGHT...MVFR/IFR WITH INCREASING RAIN CHCS FROM W TO E BY
DAYBREAK. RAIN CUD BE HEAVY AT TIMES, WITH APPROACHING CDFNT. MDT
CONFIDENCE, THOUGH LOW TO MDT ON FRONTAL POSN.

SAT...MVFR/IFR EARLY IN RAIN, HEAVY AT TIMES...INCREASING TO VFR.
RAIN ENDING FROM W TO E DURG THE MRNG/AFTERNOON. CFP LATE MRNG ERLY
AFTERNOON FROM W TO E AND WSHFT FROM SE TO WNW. MDT CONFIDENCE.

&&

.MARINE...
THERE HAS BEEN A STEADY RISE IN SEAS AT BUOY9 TO NEAR SMALL CRAFT
ADVISORY CONDITIONS. GIVEN TEXAS TOWER SEAS ARE ALSO SLOWLY
RISING, WE WILL EXTEND THE SCA FARTHER DOWN THE COAST.

TWO WEEKS AFTER RESTORATION OF A LENGTHY BUOY 44065 OUTAGE...DATA
TRANSMISSION TOPPED AT 4PM THIS PAST TUESDAY AFTERNOON. NDBC HAS
BEEN CONTACTED AND THEY WILL LET US KNOW WHAT THE PROBLEM IS.

BASICALLY NE FLOW CONTINUES THROUGH TONIGHT WITH MAX GUSTS AROUND 20
KT. SEAS BUILD TO NEAR 5 FT AND GENERALLY 1-2 FT DELAWARE BAY.


OUTLOOK...
THU...ELY FLOW WILL PERSIST AND THERE COULD BE SCA CONDS ONCE
AGAIN, WITH A BETTER CHANCE OVER THE NRN WATERS. HOWEVER, THU IS A
MARGINAL DAY AND THE LATEST GUID INDICATES WE MAY FALL JUST SHORT.

THU NIGHT INTO FRI...SCA WILL LIKELY BE NEEDED AT SOME POINT DURG
THIS PD AS SEAS INCREASE AHEAD OF AN APPROACHING CDFNT.

SAT...STRONG CFP. WINDSHIFT TO NW OR WNW. SEAS WILL INCREASE FURTHER
AND SCA WILL CONTINUE. BEST CHC FOR SCA WIND DURG THIS TIME FRAME.

&&

.CLIMATE...
MONTHLY CLM`S HAVE BEEN RUN.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...NIERENBERG
NEAR TERM...DRAG/GIGI
SHORT TERM...DRAG
LONG TERM...NIERENBERG
AVIATION...GIGI/NIERENBERG
MARINE...DRAG/GIGI/NIERENBERG
CLIMATE...





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