-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 140447
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1247 AM EDT FRI MAR 14 2014

.SYNOPSIS...
A STRONG STORM NEAR NOVA SCOTIA WILL CONTINUE TO MOVE AWAY FROM
THE REGION OVERNIGHT. HIGH PRESSURE FROM THE OHIO VALLEY WILL SETTLE
ACROSS OUR REGION FRIDAY. A LOW PRESSURE SYSTEM WILL MOVE ACROSS SOUTHERN
CANADA THIS WEEKEND CAUSING AN ATTACHED COLD FRONT TO CROSS OUR AREA
LATER SATURDAY. MORE HIGH PRESSURE WILL BUILD IN FOR EARLY NEXT WEEK.
A STORM OFF THE EAST COAST MAY AFFECT THE WEATHER OVER THE DELMARVA
ON MONDAY AND TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
GUSTY NORTHWEST WINDS WILL GRADUALLY BE DIMINISHING THROUGH THIS
EVENING AND TONIGHT AS STRONG SURFACE LOW PRESSURE NEAR NOVA SCOTIA
TRACKS FARTHER AWAY AND SURFACE HIGH PRESSURE CENTERED AROUND THE
TENNESSEE VALLEY RIDGES NORTHWARD INTO OUR REGION. SOME GUSTS TO
AROUND 25MPH REMAIN POSSIBLE THROUGH THIS EVENING, BEFORE WINDS
CONTINUE TO SUBSIDE LATE TONIGHT. A FEW ADJUSTMENTS WERE MADE TO
HOURLY TEMPS AND DEWPOINTS USING THE LAV/LAMP GUIDANCE TO
INCORPORATE CURRENT OBSERVATIONS AND TRENDS, BUT OVERALL TONIGHTS
FCST LOOKS ON TRACK.

OTHERWISE, CLEAR TO START WITH A TENDENCY FOR INCREASING CLOUDS
LATE. TEMPS/DEWS/WINDS FOR THIS FCST WERE A BLEND OF THE 12Z/13
NAM/GFS MOS GUIDANCE. SKY COVER MOSTLY GFS MOS WITH A CHECK OF NAM
AND RGEM RH ALGORITHMS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
WAA BROKEN TO OVERCAST AC DECK DURING THE MORNING SHOULD CLEAR-
DISSIPATE DURING THE AFTN WITH GUSTY SW WINDS 20 TO 25 MPH
EXPECTED DURING THE AFTN AND SCT CIRRUS. TEMPS ABOUT 20 DEGREES
MILDER MILDER THAN THE READINGS OF THIS THURSDAY AFTERNOON...BUT
STILL SLIGHTLY BELOW NORMAL. THE FCST BASIS WAS A 50 50 BLEND OF
THE 12Z/13 NAM/GFS MOS TEMPS/DEWS/WINDS AND 12Z/13 GFS MOS GUIDE
FOR SKY COVER.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MOSTLY DRY WEATHER IS EXPECTED ACROSS THE AREA THIS WEEKEND. LOW
PRESSURE WILL BE MOVING ACROSS SOUTHERN CANADA SATURDAY AND SATURDAY
NIGHT. IT HAS AN ACCOMPANYING COLD FRONT WHICH WILL CROSS THE AREA
SATURDAY EVENING. A FEW SCT SHOWERS MAY PRECEDE THE FRONT ACROSS THE
FAR NORTHERN AREAS SAT MORNING...BUT BY IN LARGE...THE FRONT WILL
CROSS THE AREA DRY. A MILD DAY IS EXPECTED SATURDAY WITH HIGHS WELL
INTO THE UPPER 50S AND LOW 60S ACROSS OUR AREA. TEMPERATURES WILL BE
CLOSER TO NORMAL (OR SLIGHTLY BELOW) SUNDAY...FOLLOWING THE FRONT.

THERE IS SOME DISAGREEMENT BETWEEN THE COMPUTER MODELS WITH
REGARDS TO WHAT WILL HAPPEN TO A LOW PRESSURE SYSTEM WHICH WILL
FORM ACROSS THE TENN VALLEY SUNDAY AND THEN MOVE ALONG THE FRONT.
THE 12Z GFS NOW HAS A SWATH OF MEASURABLE PCPN AFFECTING THE SRN
HALF OF THE AREA. TEMPERATURES SUN NGT/MON ARE COLD ENOUGH FOR
SOME SNOW ACROSS SRN NJ/SE PA AND THE NRN DELMARVA. THE 12Z ECMWF
IS BEGINNING TO TREND FURTHER NORTH WITH THE SYSTEM AND ALSO HAS
SOME MEASURABLE PCPN FOR THE SRN HALF OF THE CWA. FOR THIS
PERIOD...WE HAVE DECIDED TO GO ALONG WITH THE LATEST WPC PROGS AND
BRING HIGH CHC/LOW LIKELY POPS TO SRN NJ/DELMARVA/SE PA FOR SUN
NGT AND MONDAY FOR NOW.

MON NIGHT THRU TUE NIGHT WILL BE ANOTHER MOSTLY DRY PERIOD IN THE
EXTENDED. THERE COULD BE A FEW SHOWERS ACROSS THE SRN POCONOS TUE
NIGHT. POPS ARE ONLY IN THE SLGT CHC OR LOW CHC RANGE. ANOTHER LOW
IS SHOWN BY THE MODELS IN THE WED-THU TIME FRAME. THE WPC POPS WERE
USED IN THE FCST FOR NOW. TEMPERATURES AT THIS TIME FRAME WOULD
SUPPORT MOSTLY RAIN WITH A CHC FOR SNOW AT NIGHT.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...VFR CLEAR THEN SCT CLOUDS AOA 10000 FT OVERNIGHT
BECOMING BKN CIGS NEAR 6000 FT AFTER DAYBREAK. NW WIND GUST AROUND
25KT THROUGH THE EVENING, BECOMING LIGHT SOUTHWEST OVERNIGHT.

FRIDAY...VFR BKN CIGS AOA 6000 FT DURING THE MORNING BECOMING SCT
CLOUDS ABV 10000 FT DURING THE AFTN. SW WINDS GUSTS AROUND 20 TO
25 KT DURING THE AFTN.

OUTLOOK...
FRI NIGHT THRU SUNDAY...MOSTLY VFR. COLD FRONT WILL CROSS THE
REGION ON SATURDAY WITH SUB-VFR POSSIBLE IN RAIN/SNOW SHOWERS
EARLY NORTH OF RDG/ABE.

SUNDAY NIGHT AND MONDAY...MVFR/IFR CONDITIONS POSSIBLE WITH SNOW
POSSIBLE FOR SOUTHEAST/COASTAL AREAS. MOSTLY VFR EXPECTED FOR
CENTRAL AND NORTHWESTERN TAFS OUTSIDE OF SNOW. GUSTY NE WINDS
20-25 KT.

MONDAY NIGHT THRU TUESDAY...MOSTLY VFR.

&&

.MARINE...
WINDS REMAIN SOLIDLY IN SCA CONDITIONS ALONG THE OCEAN WATERS, SO
HAVE REPLACED THE GALE WARNING WITH AN SCA OVER THE NEXT 3 HOURS
AS WINDS WILL SLOWLY DIMINISH. THE SCA ON THE DELAWARE BAY WILL
EXPIRE AT 1 AM.

FRIDAY...ANY RESPITE FROM MARINE HEADLINES IS BRIEF. SCA LIKELY
FOR THE AFTN WITH WINDS BECOMING SOUTHWEST AND G 20-30 KT IN THE
AFTN.

VERIFICATION...THE STORM WARNING VERIFIED FOR OUR AREA (2-3HR)
LAST NIGHT WITH MAX GUSTS 53-54KT AT LEWES NOS AND CAPE MAY WXFLOW
RESPECTIVELY... GUSTS TO 48 KT AT CAPE MAY NOS...DEWEY BEACH DE
WXFLOW AND 50 KT AT SHIP JOHN SHOAL...MOST IN THE 05Z-08Z TIME
FRAME AND WELL MODELED. GLW NNJ COAST STARTED EVERYWHERE ALMOST
SIMULTANEOUSLY AROUND 03Z/13 WITH MAX GUSTS AROUND 45 KT IN THE
06Z-10Z TIME FRAME.

OUTLOOK...
FRI NIGHT...SCA CONDITIONS EXPECTED.
SAT THRU SUN EVENING...MOSTLY SUB-SCA CONDITIONS.
SUN NIGHT THRU MONDAY...SCA CONDITIONS EXPECTED.

&&

.FIRE WEATHER...
MD WILL HAVE A RED FLAG WATCH FOR FRI AFTN PER COLLABORATION WITH
OUR PARTNERS...INCLUDING NWS OFFICES WAKEFIELD AND STERLING. ALONG
THE E SIDE OF CHESAPEAKE BAY RED FLAG CRITERIA PROBABLY WONT BE
MET BUT INLAND MIGHT BE GOOD ENOUGH FOR A WARNING THOUGH THE PARTNER
TENDENCIES AT THIS TIME ARE TO FAVOR AN SPS....CERTAINLY NO MORE
THAN AN SPS FOR DE AND NJ AND NO PRODUCTS FROM E PA.

IF CONDS ARE DRIER AND WINDIER THAN NOW FCST FOR E MD THAN WE
WOULD PROBABLY CONVERT TO A WARNING PER INTEROFFICE COLLABORATION
AT 330 AM FRIDAY.

MIN RH VALUES FRI AFTN EXPECTED TO BE BETWEEN 20 AND 30 PERCENT,
AND GUSTY SW WIND 20-30 MPH DURING THE AFTN.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...FIRE WEATHER WATCH FROM NOON EDT TODAY THROUGH THIS AFTERNOON
     FOR MDZ008-012-015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
     ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL 1 AM EDT EARLY THIS MORNING FOR
     ANZ430-431.

&&

$$
SYNOPSIS...O`HARA
NEAR TERM...DRAG/KLINE
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...DRAG/O`HARA
MARINE...DRAG/JOHNSON/O`HARA
FIRE WEATHER...