Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 201958
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
358 PM EDT MON OCT 20 2014

.SYNOPSIS...
LOW PRESSURE CENTERED OVER LAKE HURON THIS AFTERNOON WILL DRIFT
SOUTHEASTWARD. IT IS FORECAST TO PASS OFF THE MIDDLE ATLANTIC
COAST ON TUESDAY NIGHT. THE LOW IS THEN EXPECTED TO MOVE SLOWLY
NORTH AND NORTHEASTWARD REACHING THE WATERS OFF CAPE COD AROUND
THURSDAY NIGHT AND ARRIVING IN NOVA SCOTIA ON FRIDAY NIGHT. HIGH
PRESSURE IS ANTICIPATED TO BUILD INTO OUR REGION FROM THE
SOUTHWEST FOR FRIDAY INTO SATURDAY. A COLD FRONT APPROACHING FROM
NORTHWEST IS EXPECTED ON SATURDAY NIGHT WITH ANOTHER AREA OF HIGH
PRESSURE FOLLOWING FOR SUNDAY AND MONDAY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
REGIONAL RADAR HAS BEEN SHOWING A LOT OF RETURNS THIS AFTERNOON
TO OUR WEST TIED TO THE THETA-E SURGE OCCURRING. THE MID-LEVELS
REMAINS VERY DRY AND SURFACE DEW POINT DEPRESSION VALUES ARE STILL
20 TO 25F SO BASICALLY A LOT OF VIRGA IS BEING SEEN. THE AIR MASS
CONTINUES TO MODIFY TONIGHT WITH DEEPER LAYER MOISTURE EXPECTED TO
ARRIVE AFTER MIDNIGHT. THE LEAD IMPULSE, WITHIN THE LARGER GREAT
LAKES TROUGH, NEARS FROM THE WEST AS ITS SURFACE INFLECTION SLOWLY
DIVES INTO NORTHWESTERN PENNSYLVANIA LATE TONIGHT. WE CONTINUE
WITH CHANCE POPS ACROSS OUR WESTERN ZONES STARTING EARLY TUESDAY
MORNING AS THE LOW APPROACHES WITH ITS WEAKENING FRONTAL BOUNDARY.

TEMPERATURES WILL FEEL BALMY COMPARED TO THIS MORNINGS LOWS.
EXPECTING OVERNIGHT LOWS IN THE MID TO UPPER-40S IN MOST PLACES. A
BLEND OF THE MET/MAV WORKED BEST.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
A FILLING SURFACE LOW PRESSURE SYSTEM TO OUR NORTHWEST SLIDES
FURTHER SOUTH LATE TOMORROW MORNING AND BECOMES MORE BROAD. THERE
WILL LIKELY BE A DRY SLOT SETTING UP ACROSS THE CENTRAL PORTION OF
OUR CWA, THOUGH THE EXACT PLACEMENT IS STILL SUSPECT. A BETTER
DEFINED AND STRONGER COASTAL LOW FORMS OFF THE DELMARVA LATE IN
THE DAY AND MOVES TOWARDS THE NORTHEAST...LOTS OF JET DYNAMICS
INVOLVED. CHANCES FOR SHOWERS INCREASES TO LIKELY DURING THE DAY
MAINLY ACROSS OUR WESTERN AND NORTHERN ZONES, THOUGH STILL NOT
ENTIRELY SOLD ON A COMPLETELY DRY DAY ELSEWHERE SO WE CONTINUE THE
CHANCE POPS. NOT LOOKING AT A COMPLETE WASHOUT TOMORROW WITH
WIDELY SCATTERED SHOWERS THE MOST PROBABLE. WE KEEP THUNDER OUT OF
THE FORECAST, EVEN WITH STEEPER MID-LEVEL LAPSE RATES FORMING, AS
THE BETTER DYNAMICS OFFSHORE COULD ROB INLAND AREAS OF ALL THE
LUSTER. TEMPERATURES WILL CONTINUE TO CLIMB WITH THE MODIFYING
AIR MASS AND SOUTHERLY AHEAD OF THE LOW PRESSURE SYSTEM.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A UPPER LEVEL JET EXTENDED FROM WESTERN HUDSON BAY, ACROSS
WESTERN ONTARIO TO THE WESTERN PART OF THE GREAT LAKES REGION THIS
AFTERNOON. A MID LEVEL LOW IS FORECAST TO DEVELOP IN THE LIFT
UNDER ITS LEFT FRONT QUADRANT TONIGHT OVER THE LAKE HURON
VICINITY. THE MID LEVEL LOW IS EXPECTED TO BE LOCATED OVER EASTERN
WEST VIRGINIA ON TUESDAY EVENING AND IT SHOULD PASS OFF THE
DELMARVA COAST ON WEDNESDAY MORNING. THE FEATURE IS THEN
ANTICIPATED TO MEANDER OFF OUR COAST FROM WEDNESDAY AFTERNOON INTO
THURSDAY EVENING BEFORE LIFTING NORTHEASTWARD AND REACHING THE
WATERS OFF CAPE COD ON FRIDAY MORNING. A SURFACE LOW IS FORECAST
TO FOLLOW THE MID LEVEL LOW CLOSELY DURING THE PERIOD.

WE ARE EXPECTING THE POTENTIAL FOR RAIN FROM TUESDAY NIGHT
THROUGH THURSDAY MORNING. THE POSSIBILITY OF MODERATE TO HEAVY
RAINFALL SHOULD BE MOSTLY ON THE EAST SIDE OF THE DEVELOPING MID
LEVEL LOW. AS A RESULT, WE ARE NOT ANTICIPATING MUCH MODERATE TO
HEAVY RAINFALL IN OUR REGION. THE ONLY EXCEPTION IS IN OUR COASTAL
AREAS FROM TUESDAY NIGHT INTO WEDNESDAY WHERE RAINFALL AMOUNTS MAY
APPROACH AN INCH AT SOME LOCATIONS. ALSO, MARGINAL INSTABILITY IN
THAT AREA MAY TRANSLATE INTO ISOLATED LIGHTNING AND THUNDER.
REGARDLESS, THE EXPECTED RAINFALL TOTALS SHOULD NOT RESULT IN ANY
FLOODING PROBLEMS.

AS THE LOW BEGINS TO PULL AWAY TO OUR NORTHEAST ON THURSDAY
NIGHT, THE POTENTIAL FOR RAIN SHOWERS SHOULD END GRADUALLY IN OUR
AREA.

A COUPLE OF REINFORCING MID LEVEL SHORT WAVES SHOULD DROP OVER
OUR REGION FROM THE NORTHWEST IN THE CYCLONIC FLOW AROUND THE
DEPARTING MID LEVEL LOW OVER THE COMING WEEKEND. THE SHORT WAVES
ARE NOT EXPECTED TO HAVE MUCH MOISTURE ASSOCIATED WITH THEM.
THEREFORE, WE ARE NOT ANTICIPATING ANY PRECIPITATION AT THAT TIME.

A MID LEVEL RIDGE FROM THE WEST SHOULD BUILD TOWARD OUR REGION
FOR SUNDAY AND MONDAY.

DAYTIME HIGHS ARE FORECAST TO BE A BIT BELOW NORMAL WITH THE RAIN
ON WEDNESDAY AND THURSDAY. READINGS SHOULD RETURN TO NEAR NORMAL
FOR THE PERIOD FROM FRIDAY THROUGH MONDAY.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

THIS AFTERNOON - TONIGHT...MOSTLY VFR. SOUTHERLY WINDS AROUND 10
KNOTS BECOME LIGHT AND VARIABLE LATE THIS EVENING. SOME PATCHY
MVFR DRIZZLE/MIST IS POSSIBLE AT ABE/RDG EARLY TUESDAY MORNING.
HIGH CONFIDENCE EXCEPT FOR MIST DEVELOPMENT.

TUESDAY...MOSTLY VFR. WEAK LOW PRESSURE SYSTEM NEARS FROM THE
WEST-NORTHWEST. WINDS START OFF LIGHT OUT OF THE SOUTH, MAYBE
SOUTHEAST, AND VEER TOWARDS THE SOUTHWEST LATE IN THE PERIOD. KEEP
LOW CONFIDENCE ON SHOWER IMPACTS AT TERMINALS SO KEEP THE MENTION
OUT FOR THE TIME BEING. MEDIUM CONFIDENCE.

OUTLOOK...
TUESDAY NIGHT THROUGH THURSDAY...CONDITIONS VARYING BETWEEN VFR
AND MVFR IN PERIODS OF RAIN.

THURSDAY NIGHT...MAINLY VFR WITH A CHANCE OF SHOWERS.

FRIDAY THROUGH SATURDAY...MAINLY VFR.

&&

.MARINE...
TONIGHT...SUB-SCA CONDITIONS EXPECTED TONIGHT. SOUTHERLY WINDS
MAY GUST INTO THE LOW-20 KNOT RANGE FOR A TIME AS SEAS REMAIN
AROUND 3 FEET.

TUESDAY...SUB-SCA CONDITIONS. WINDS BACK TOWARDS THE SOUTH-
SOUTHWEST TOMORROW AFTERNOON AND BEGIN TO DECREASE AS WEAK LOW
PRESSURE MOVES IN OVERHEAD. SEAS REMAIN 2 TO 3 FEET.

OUTLOOK...
TUESDAY NIGHT...NO MARINE HEADLINES ARE ANTICIPATED.

WEDNESDAY...NORTHERLY WIND GUSTS OF 25 TO 30 KNOTS ARE POSSIBLE.

WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY WIND GUSTS
OF 25 TO 30 KNOTS ARE POSSIBLE.

SATURDAY...NO MARINE HEADLINES ARE ANTICIPATED.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...IOVINO
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...IOVINO
AVIATION...IOVINO/HEAVENER
MARINE...IOVINO/HEAVENER






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