Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 181858
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
258 PM EDT FRI APR 18 2014

.SYNOPSIS...
A DISSIPATING FRONTAL BOUNDARY WILL MOVES ACROSS THE REGION TONIGHT
AND INTO THE FIRST HALF OF SATURDAY. SURFACE HIGH PRESSURE WILL
BUILD ACROSS EASTERN CANADA DOWN THROUGH THE NORTHERN MID-ATLANTIC
ON SATURDAY AFTERNOON. THE HIGH WILL SHIFT TO THE EASTERN SEABOARD
SUNDAY THROUGH MONDAY. ANOTHER FRONTAL BOUNDARY IS THEN EXPECTED TO
AFFECT THE AREA NEXT TUESDAY OR WEDNESDAY, FOLLOWED BY HIGH PRESSURE
THURSDAY INTO FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THE WRF-NMMB INITIALIZATION WAS BETTER AT 500MB, BOTH THE WRF AND
GFS ABOUT THE SAME AT 850MB AND THE GFS BETTER AT 925MB. OVERALL NOT
THAT GREAT A DIFFERENCE TO SHOW MODELING IMPACT DIFFERENCES THROUGH
THE SHORT
TERM.

NO HEADLINES FOR TONIGHT. WE DID ADD SOME PATCHY FROST IN THE PINE
BARRENS. DEW POINTS AND UNCERTAINTIES TO CLOUD THICKNESSES SHOULD BE
LIMITING FACTORS FOR WIDESPREAD FROST.

THE STRATOCU LEVEL WINDS ARE IN THE PROCESS OF BECOMING OFFSHORE.
COUPLED WITH LOWERING RAP FCST RH LEVELS AT THAT LEVEL TELL US THAT
WHAT IS LEFT OF THOSE CLOUDS NEAR THE COAST SHOULD DRIFT OFFSHORE
AND HAVE TO FIGHT AN INCREASINGLY WRLY FLOW TO ADVECT BACK.  MUCH OF
THE CLOUDINESS OVERNIGHT IS CIRRUS BASED. THERE MAY BE SOME DEBRIS
STRATOCU FROM THE APPROACHING CDFNT LATER TONIGHT. OVERALL
COVERAGE FROM THEM NOT EXPECTED TO BE MUCH.

WINDS SHOULD BE LIGHT TONIGHT, SO IF THE CIRRUS THICKNESS WANES, WE
MAY BE TOO HIGH WITH MIN TEMPS IN OUTLYING AREAS. DEW POINTS HAVE
RESPONDED UPWARD IN THE EAST TO SOUTHERLY FLOW, SO WE DO HAVE A MUCH
HIGHER FLOOR THAN WE HAVE HAD THE LAST COUPLE OF NIGHTS FOR MIN
TEMPS.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
A DEFORMATION ZONE IS EXPECTED TO DEVELOP NORTH OF THE CLOSING LOW
IN DELMARVA ON SATURDAY. THIS SHOULD BE THE CUT-OFF FOR ANY
CLOUDINESS FROM THE SOUTHEAST COAST SYSTEM. BY THE MIDDLE OF
SATURDAY MORNING CLOUDS SHOULD BE LIMITED TO DELMARVA AND BE CIRRUS.
THE AIR MASS BEHIND THE COLD FRONT IS VERY DRY AND CONVECTIVE TEMPS
ARE NOT PREDICTED TO BE REACHED. WE SIDED CLOSER TO 850MB FULL SUN
MAX TEMP POTENTIAL THAN THE COLDER 925S GIVEN THE PREDICTED MIXING.
MAX TEMPS ARE CLOSER TO HIGHER STAT GUIDANCE AND ALSO TOWARD THE
FULL SUN SOUNDING FCST MACROS. THE BETTER MIXING WILL ALSO MAKE FOR
A BREEZIER DAY, BUT NOT THAT FAR FROM TYPICAL FOR APRIL.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE PERIOD BEGINS WITH A SURFACE HIGH TO OUR NORTH AND A SURFACE LOW
WELL TO OUR SOUTH. THE CENTER OF THE HIGH IS FORECAST TO MOVE OFF
THE MAINE COAST ON SUNDAY. THE AXIS OF THE HIGH GETS STRETCHED ALONG
THE EASTERN SEABOARD ON SUNDAY NIGHT. THIS HELPS TO PUSH THE LOW OFF
THE CAROLINAS FURTHER OUT TO SEA. ON MONDAY, THE SURFACE HIGH STARTS
TO WEAKEN, BUT REMAINS ACROSS THE REGION. ON MONDAY NIGHT, A SURFACE
LOW IS FORECAST TO MOVE INTO THE GREAT LAKES AS A COLD FRONT TRACKS
THROUGH THE OHIO VALLEY. AS OF NOW, IT LOOKS LIKE THIS COLD FRONT
STAYS TO OUR WEST ON TUESDAY AND PASSES THROUGH TUESDAY NIGHT. THE
UPPER LOW MOVES THROUGH ON WEDNESDAY. SURFACE HIGH PRESSURE IS
FORECAST TO BUILD ONCE AGAIN ON WEDNESDAY NIGHT AND PERSIST AT LEAST
THROUGH THURSDAY NIGHT.

TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL ON SUNDAY, NEAR NORMAL
ON MONDAY, ABOVE NORMAL ON TUESDAY, NEAR NORMAL WEDNESDAY AND
THURSDAY, AND ABOVE NORMAL ON FRIDAY.

THE ONLY PRECIPITATION EXPECTED DURING THE EXTENDED IS ASSOCIATED
WITH THE COLD FRONT ON TUESDAY NIGHT. AS OF NOW, WE WON`T MENTION
ANY THUNDER AS THE BEST CAPE AND LI`S ARE SOUTH AND WEST OF THE
REGION.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

PREDOMINATELY VFR CONDITIONS WITH THE 18Z TAFS.

FOR THE REST OF THIS AFTERNOON, SOME MVFR CIGS MAY LINGER AT
COASTAL AIRPORTS, BUT THE TREND TOWARD DISSIPATION IS CONTINUING.
ALL OTHER TERMINALS AND AIRPORTS, NO CIG IS PREDICTED BELOW CIRRUS
LEVEL. WINDS SHOULD BE MAINLY SOUTHEAST AT LESS THAN 10 KNOTS.

SEA BREEZE FRONT NOT APPARENT ON OUR 88D. TIME IS RUNNING OUT FOR IT
TO FORM AS IT SHOULD MELD WITHIN THE GENERAL VEERING SOUTHEAST TO
SOUTH SYNOPTIC SCALE FLOW LATER THIS AFTERNOON.

TONIGHT, A CIRRUS DECK OF CLOUDS EXPECTED WITH GENERALLY LIGHT AND
VARIABLE WINDS. THERE COULD BE A FEW STRATOCU LEVEL CLOUDS CLOSE
TO THE PASSAGE OF THE COLD FRONT. ANY DIRECTION OVERNIGHT IF THERE
IS ANY WILL LIKELY BE SOUTH TO SOUTHWEST. FOG, CONFIDENCE OF IT
OCCURRING TOO LOW TO INCLUDE AT TERMINALS. ALTHOUGH, VERY RURAL
AIRPORTS MIGHT HAVE SOME TOWARD MORNING.

SATURDAY. A COLD FRONTAL PASSAGE EARLY WITH A BRISKER NORTH TO
NORTHWEST WIND EXPECTED WITH PEAK GUSTS NEAR 20 KTS. NOT TOTALLY
CONFIDENT ABOUT GUSTINESS, MAY END UP BEING A SUSTAINED 10 TO 15
KT DAY. ANY SEA BREEZE FRONT WOULD FORM LATE IN THE DAY AND BE
CONFINED CLOSE TO THE IMMEDIATE COAST. CLEAR SKIES PREDICTED.

OUTLOOK...
SAT NIGHT THRU MON...MOSTLY VFR, BUT WITH A SURFACE HIGH
SETTING UP TO THE NORTH, THEN NORTHEAST, SUNDAY INTO SUNDAY NIGHT,
WE`LL NEED TO WATCH FOR ANY STRATUS DEVELOPMENT THAT COULD LOWER
CEILINGS.
MON NIGHT THROUGH WEDNESDAY...MOSTLY VFR WITH SCT SHOWERS LATE
TUESDAY AND TUESDAY NIGHT.

&&

.MARINE...
WE WILL CONTINUE THE SCA FOR SEAS ON THE OCEAN THROUGH TONIGHT. WAVE
WATCH CONTINUES TO BE SLIGHTLY TOO LOW, ALTHOUGH THE GAP IS CLOSING.

EARLY THIS EVENING THERE MAY BE AN UP THE DELAWARE BAY WIND MAX,
OTHERWISE WINDS TONIGHT WINDS SHOULD BE RELATIVELY LIGHT PRECEDING
THE FRONT.

ON SATURDAY, WINDS SHOULD START INCREASING BEHIND THE FRONT, BUT THE
BETTER MIXING DURING THE DAYTIME WILL BE ON LAND. SEAS ON THE OCEAN
SHOULD BE BELOW SMALL CRAFT ADVISORY CRITERIA FOR MOST OF THE
DAYTIME HOURS.

OUTLOOK...
SATURDAY NIGHT...SUB-SCA CONDITIONS.
SUNDAY AND SUNDAY NIGHT...SCA CONDITIONS ON THE OCEAN AND
POTENTIALLY THE LOWER DELAWARE BAY.
MONDAY THRU TUESDAY...SUB-SCA CONDITIONS.
TUESDAY NIGHT INTO WEDNESDAY...SCA CONDITIONS.

&&

.FIRE WEATHER...
IN NJ AND PA FINE FUELS MOISTURE HAVE FALLEN WITHIN RED FLAG
CRITERIA AND MEAN RH(S) ON SATURDAY AFTERNOON SHOULD FALL BELOW 30
PERCENT. BUT WE ARE NOT CONFIDENT ABOUT FREQUENT GUSTS EXCEEDING 20
MPH. WE WILL MAKE MENTION IN THE FIRE WEATHER FORECAST, BUT
CONFIDENCE IS TOO LOW TO ISSUE A WATCH. IN DE AND MD, THE POTENTIAL
AND CRITERIA FOR STRONGER WINDS DO NOT LOOK LIKE THEY WILL BE
REACHED PLUS THE AFTN RH LEVELS MAY ALSO BE MORE MARGINAL.

&&

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

&&

$$
SYNOPSIS...KRUZDLO
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...KRUZDLO
AVIATION...GIGI/KRUZDLO
MARINE...GIGI/KRUZDLO
FIRE WEATHER...GIGI





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