Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KPHI 061948
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
348 PM EDT MON JUL 6 2015

.SYNOPSIS...
A WARM FRONT IS FORECAST TO LIFT NORTHWARD THROUGH OUR REGION
FROM TONIGHT INTO TUESDAY MORNING. ANOTHER FRONTAL BOUNDARY IS
EXPECTED TO ARRIVE FROM THE NORTHWEST ON WEDNESDAY. THE FRONT IS
ANTICIPATED TO MEANDER IN OUR VICINITY FROM WEDNESDAY NIGHT
THROUGH THURSDAY NIGHT AS WEAK AREAS OF LOW PRESSURE MOVE ALONG
IT. THE FRONT IS FORECAST TO MOVE TO OUR SOUTH FOR FRIDAY AND FOR
THE WEEKEND, ALLOWING HIGH PRESSURE TO NUDGE DOWN FROM THE
NORTHWEST AND NORTH. THE BOUNDARY MAY RETURN AS A WARM FRONT EARLY
NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LARGE MID-LEVEL CLOSED LOW TO OUR SOUTHWEST IS ALLOWING FOR
NUMEROUS SHOWERS AND EMBEDDED THUNDER TO DEVELOP JUST TO THE WEST
OF OUR CWA. WE ARE HOWEVER, STARTING TO SEE AN UPTICK IN THE
HOMEGROWN CONVECTION ACROSS SOUTHERN DELMARVA AT THIS TIME, AS THE
STORMS PROPAGATE TOWARDS THE NORTH-NORTHEAST THIS EVENING. THE
GREATEST AMOUNT OF MLCAPE EXISTS ACROSS DELMARVA NORTHWARD TOWARDS
PHILLY BEFORE TAPERING OFF, SO WHILE WE CAN NOT RULE OUT ISOLATED
SHOWERS NORTH OF PHILLY THIS EVENING AND TONIGHT, THE CHANCES OF
THUNDER DECREASE GREATLY.

AT THIS POINT THE SEVERE THREAT SHOULD BE CONFINED TO DELMARVA
WITH GREATER SHEAR FOR BETTER ORGANIZED STORMS, HIGHER MLCAPE
VALUES, AND A BETTER LOW-LEVEL VEERING PROFILE. THAT BEING SAID IT
LOOKS MARGINAL AS SPC CONTINUES THE MENTION OF ISOLATED SEVERE IN
THIS AREA. ONE THING OF CONCERN IS THE CONTINUED NORTHWARD
PROGRESSION OF THE STORMS WHICH MAY LEAD TO TRAINING SHOULD MORE
STORMS CONTINUE TO INITIATE ACROSS DELMARVA...LOCALIZED FLOODING
MAY BE AN ISSUE.

THE ABOVE MENTIONED LOW IS FORECAST TO OPEN AND MOVE TOWARDS THE
NORTHEAST LATE TONIGHT. OUR NORTHWESTERN ZONES WILL STILL HAVE THE
BETTER CHANCES FOR SHOWERS THROUGH THE OVERNIGHT HOURS, EVEN WITH
THE LACK OF INSTABILITY...ILL-DEFINED COLD CORE ALOFT, BUT DOES
NOT APPEAR COLD ENOUGH FOR STRONGER UPDRAFTS.

OVERNIGHT TEMPERATURES WILL DROP BACK INTO THE UPPER-60S TO LOW-
70S AS DEW POINTS REMAIN QUITE MOIST ACROSS THE REGION. THIS WILL
SETUP POCKETS OF FOG, NOT SURE HOW DENSE AT THIS TIME, WITH THE
PROLONGED ONSHORE FLOW IN PLACE.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
AS ONE MID-LEVEL WAVE MOVES OUT THERE IS ANOTHER ONE RIGHT ON ITS
TAILS. TIMING IS STILL A BIT SUSPECT BUT IT APPEARS THAT THE MID
TO LATE AFTERNOON TIME PERIOD IS WHEN THE BETTER CHANCES FOR
SHOWERS EXISTS...PEAK HEATING, AND MOSTLY ACROSS OUR NORTHWESTERN
ZONES. BY THE TIME WE WILL BE IN THE WARM SECTOR, AS THE WARM
FRONT FROM MONDAY CONTINUES TO LIFT TOWARDS THE NORTH-NORTHEAST.
PWATS SHOULD BE AT THEIR HIGHEST, AROUND 1.75-2.00 INCHES, SO ANY
OF THE SHOWERS WILL BECOME HEAVY RAINERS. TEMPERATURES WILL BE
SEVERAL DEGREES WARMER WITH THE ADDITION OF A MORE WESTERLY
SURFACE FLOW COMPONENT SO WE COULD REACH 90F IN AND AROUND THE
PHILLY METRO AREA TOMORROW AFTERNOON.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE MID LEVEL FLOW IS EXPECTED TO REMAIN SOMEWHAT ZONAL EAST OF
THE ROCKIES FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS LOW
PRESSURE MEANDERS OFF THE CALIFORNIA COAST, MOVES INLAND AND
FILLS. THE MODEL GUIDANCE IS TRENDING TOWARD GREATER AMPLIFICATION
OF THE MID LEVEL PATTERN OVER THE CENTRAL AND EASTERN STATES LATE
IN THE WEEK WITH RIDGING DEVELOPING OVER THE GREAT LAKES.
EVENTUALLY, A LONG WAVE RIDGE IS ANTICIPATED TO RETURN OVER THE
ROCKY MOUNTAIN STATES DURING THE WEEKEND WITH A TROUGH SETTLING
OVER THE EAST.

A MID LEVEL SHORT WAVE TROUGH IS FORECAST TO BE PULLING AWAY FROM
OUR AREA ON TUESDAY EVENING. ANY RESIDUAL SHOWERS AND
THUNDERSTORMS SHOULD COME TO AN END AT THAT TIME. A BREAK IN THE
PRECIPITATION POTENTIAL IS ANTICIPATED FOR MUCH OF TUESDAY NIGHT
INTO EARLY WEDNESDAY.

IT CONTINUES TO APPEAR AS THOUGH A FRONTAL BOUNDARY WILL DROP
INTO OUR REGION ON WEDNESDAY AND IT SHOULD REMAIN ACROSS OUR
FORECAST AREA THROUGH THURSDAY NIGHT. THE NEARLY ZONAL FLOW WILL
MAKE IT DIFFICULT TO TIME ANY MID LEVEL IMPULSES AND ASSOCIATED
WEAK SURFACE WAVES. REGARDLESS, A CHANCE OF SHOWERS AND
THUNDERSTORMS WILL EXIST THROUGH THAT PERIOD OF TIME. THE GUIDANCE
IS SUGGESTING THAT A MID LEVEL SHORT WAVE TROUGH AND WEAK SURFACE
LOW MAY PASS ACROSS OUR FORECAST AREA ON THURSDAY NIGHT PULLING
THE SURFACE BOUNDARY TO THE SOUTH OF MARYLAND AND DELAWARE.

PRECIPITABLE WATER VALUES ARE FORECAST TO RISE NEAR OR ABOVE 2
INCHES DURING THE MID WEEK PERIOD IN MUCH OF OUR REGION. ANY
THUNDERSTORMS COULD BRING HEAVY DOWNPOURS ALONG WITH LOCALIZED
FLOODING OF ROADWAYS AND AREAS OF POOR DRAINAGE. ALSO, WE WILL
KEEP AN EYE ON THE FLASH FLOODING POTENTIAL ESPECIALLY IF CERTAIN
AREAS ARE AFFECTED BY HEAVY RAINFALL ON MORE THAN ONE DAY.

THE AMPLIFYING MID LEVEL FLOW SHOULD ALLOW HIGH PRESSURE TO WORK
ITS WAY TOWARD OUR REGION FROM THE NORTHWEST AND NORTH FOR THE
COMING WEEKEND. AS A RESULT, WE WILL NOT INDICATE A CHANCE OF
SHOWERS AND THUNDERSTORMS FOR THAT PERIOD OF TIME.

WE WILL FORECAST A RETURNING CHANCE OF SHOWERS AND THUNDERSTORMS
FOR EARLY NEXT WEEK WITH THE SURFACE BOUNDARY EXPECTED TO RETURN
NORTHWARD AS WARM FRONT.

DAYTIME TEMPERATURES ARE ANTICIPATED TO BE WITHIN A FEW DEGREES
OF NORMAL FOR THE PERIOD FROM TUESDAY NIGHT THROUGH MONDAY.
NIGHTTIME TEMPERATURES ARE FORECAST TO BE ABOVE NORMAL.

&&

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

THIS AFTERNOON...MOSTLY VFR WITH POCKETS OF MVFR CLOSER TOWARDS
THE COAST. ISOLATED TO WIDELY SCATTERED SHOWERS EXPECTED THIS
AFTERNOON AND EVENING ACROSS THE REGION. SOME THUNDERSTORM
ACTIVITY IS ALSO POSSIBLE WITH BETTER CHANCES ACROSS THE I-95
TERMINALS INTO EASTERN PENNSYLVANIA AND SOUTHWARD INTO DELMARVA.
SOUTHEASTERLY WINDS AROUND 10 KNOTS EXPECTED TO CONTINUE.

TONIGHT...VFR TRENDING TOWARDS MVFR/IFR. WE BEGIN TO LOSE THE
SHOWERY ACTIVITY LATE TONIGHT. CONTINUED ONSHORE FLOW KEEPS ENOUGH
LOW-LEVEL MOISTURE SURGING INTO THE REGION TO BRING CIGS AND VSBYS
INTO THE IFR RANGE LATE TONIGHT.

TUESDAY...TRENDING TO VFR. CIGS AND VSBYS REBOUND BY LATE TUESDAY
MORNING WITH BETTER SURFACE HEATING AND THE WINDS VEERING TOWARDS
THE SOUTHWEST. MORE SCATTERED SHOWERS ARE POSSIBLE DURING THE
AFTERNOON, BUT MOSTLY NORTH OF RDG-ABE.

OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY MORNING...CONDITIONS POSSIBLY
LOWERING TO MVFR OR IFR IN LOW CLOUDS, HAZE AND FOG ESPECIALLY
DURING THE LATE NIGHT AND EARLY MORNING HOURS.

WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...A CHANCE OF SHOWERS
AND THUNDERSTORMS WHICH MAY CAUSE CONDITIONS TO LOWER TO MVFR OR
IFR AT TIMES.

FRIDAY THROUGH SATURDAY...MAINLY VFR.

&&

.MARINE...
SUB-SCA CONDITIONS EXPECTED TONIGHT AND TOMORROW WITH
SOUTHEASTERLY WINDS VEERING TOWARDS THE SOUTH-SOUTHWEST BY TUESDAY
AFTERNOON AROUND 15 KNOTS. SEAS WILL INCREASE UPWARDS OF 4 FEET BY
TUESDAY AFTERNOON AS WELL.

OUTLOOK...
TUESDAY NIGHT THROUGH 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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.