Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 260124
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
924 PM EDT FRI JUL 25 2014

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL MOVE FARTHER OFFSHORE ON SATURDAY
SETTING UP A RETURN FLOW. A WARM FRONT CROSSES THE REGION LATE ON
SATURDAY WHILE THE PARENT LOW PRESSURE SYSTEM MOVES THROUGH THE
GREAT LAKES. THE ATTENDANT COLD FRONT SWINGS THROUGH LATE ON
SUNDAY INTO MONDAY FOLLOWED BY ANOTHER HIGH PRESSURE SYSTEM.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
HIGH PRESSURE WILL CONTINUE TO DRIFT OUT TO SEA OVERNIGHT. A
LIGHT SOUTH TO SOUTHWEST SURFACE FLOW IS ANTICIPATED. TEMPERATURES
SHOULD DROP INTO THE MIDDLE AND UPPER 50S UP NORTH AND INTO THE
LOWER AND MIDDLE 60S ELSEWHERE.

HIGH CLOUDS FROM THE WEST AND NORTHWEST WILL DRIFT OVERHEAD
DURING THE NIGHT. THEY SHOULD BE THIN AND WILL LIKELY HAVE LIMITED
IMPACT ON THE TEMPERATURES.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
CONFIDENCE IS NOT HIGH IN EITHER DIRECTION ABOUT CONVECTION AND
THE END RESULT FOR NOW IS A RATHER GENERIC VANILLA SUMMER`S DAY
FORECAST FOR SATURDAY.

THE MODELS HAVE BEEN PRETTY CONSISTENT IN POOLING DEW POINTS AS
SATURDAY PROGRESSES IN OUR CWA. PARTLY BECAUSE OF THE
AFOREMENTIONED SHORT WAVES AND ALSO LOOKS TO BE SOME SFC WIND
CONVERGENCE. THEY ACTUAL SPIKE UPWARD HAS BECOME MORE LOGICAL FROM
YESTERDAY WHERE SOME OF THE MODEL FCST SFC DEW POINTS WERE
REACHING THE MID 70S. STILL MOS GUIDANCE IS FORECASTING DEW POINTS
5 TO 10F LOWER THAN THEIR OWN MODEL GUIDANCE. THIS PLUS TEETERING
CLOSE TO THE EDGE OF THE AVAILABLE CAPE FOR THUNDER AND WHETHER OR
NOT THE CAP WOULD HOLD. GIVEN THE SHORT WAVES ALOFT, THINKING THE
CAP WONT. THIS LEAVES THE DEW POINTS. IF THEY DONT GET INTO THE
MID 60S ALONG THE COASTAL PLAIN, CHANCES ARE THERE WONT BE ENOUGH
CAPE. NORTH AND WEST THERE IS ALWAYS THE OROGRAPHIC INFLUENCE THAT
MAY COMPENSATE FOR LOWER DEW POINTS. MODIFIED SOUNDING CONVECTIVE
TEMPS ARE PREDICTED TO BE REACHED, SO WE DID EXPAND THE MENTION OF
DURING THE AFTERNOON THUNDER GEOGRAPHICALLY. CONVERSELY SINCE MOST
MESOSCALE MODELS ARE CONVERGING SOUTH AND EAST TOWARD THE HIGHER
DEW POINT POOLING, WE DID LOWER POPS IN THE NORTHWEST PART OF OUR
CWA.

PREDICTED 1395 1000-850MB THICKNESSES ARE NOT BUYING MAX TEMPS AS
HIGH AS THEY HAVE DONE IN PAST SUMMERS. FULL SUN MACROS LOOK
OVERCOOKED AND MAX TEMPS WERE KEPT CLOSER TO 10-11C OVER PREDICTED
925MB TEMPS. THIS IS CLOSE TO STAT GUIDANCE AND CONTINUITY. GFS
THERMAL GUIDANCE WENT DOWN ABOUT 1-2C FROM THURSDAY`S LEVELS AOB
850MB.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
SUNDAY...A DECAYING MCS SHOULD BE DIVING WELL TO THE SOUTHWEST OF
OUR REGION AS ONE MID-LEVEL SHORTWAVE CRUISES THROUGH. SURFACE
WARM FRONT SHOULD BE LIFTING THROUGH DURING THE EARLY PART OF THE
MORNING. MOISTURE WILL CONTINUE TO INCREASE WITH A SOUTHWEST
SURFACE FLOW WITH PWATS EXCEEDING 1.5 INCHES. EARLY MORNING
SHOWERS AND THUNDERSTORMS SHOULD BE WANING BY LATE MORNING AS MOST
OF THE OPERATIONAL GUIDANCE SHOWS THE REGION BREAKING OUT. NOT
QUITE SURE HOW LONG LIVED THE BREAK WILL BE AS CONVECTIVE
TEMPERATURES SHOULD EASILY BE MET AS HIGHS APPROACH 90F SO WE
CONTINUE WITH CHANCE POPS. BETTER FORCING MOVES IN ALOFT WITH A
MUCH STRONGER SHORTWAVE AND APPROACHING COLD FRONT LATER ON
SUNDAY. BETTER HEIGHT FALLS, SHEAR PROFILES AND LESS CAPPING
SHOULD ALLOW FOR MUCH MORE ORGANIZED CONVECTION TO OCCUR. SPC HAS
US IN DAY 3 OUTLOOK AT THIS TIME SO WILL CONTINUE WITH THE HWO
HIGHLIGHTING.

MONDAY...COLD FRONT WILL CONTINUE TO MOVE THROUGH THE REGION,
THOUGH NOT AT A BLISTERING PACE. WEAK SURFACE CYCLOGENESIS IS
POSSIBLE ON MONDAY AS THE FRONT SITS JUST TO OUR EAST SO WE KEEP
CHANCE POPS IN PLACE DURING THE DAY. TEMPERATURES SHOULD END UP
BEING AROUND AVERAGE ACROSS THE EAST AND SLIGHTLY BELOW ACROSS THE
WEST.

TUESDAY - THURSDAY...DRYING TREND SHOULD COMMENCES ACROSS A
MAJORITY OF THE REGION, BUT WITH THE MID-LEVEL TROUGH/COLD POOL
ALOFT, AND THE SLIGHTEST HINT OF INSTABILITY AROUND, ISOLATED
SHOWERS ARE POSSIBLE ON TUESDAY...BETTER FURTHER NORTH. THE
CHANCES FOR SHOWERS DECREASES EACH AFTERNOON THEREAFTER.
TEMPERATURES SHOULD END UP BEING BELOW NORMAL FOR LATE JULY
STANDARDS.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH AN
INCREASE IN CIRRUS DURING THE NIGHT AND THE DEVELOPMENT OF CUMULUS
ON SATURDAY WITH BASES ABOVE 4500 FEET. THERE IS THE POTENTIAL FOR
ISOLATED SHOWERS AND THUNDERSTORMS ON SATURDAY. HOWEVER, THEIR
COVERAGE SHOULD BE LIMITED AND THEY MAY VERY WELL NOT IMPACT ANY
OF OUR TAF SITES.

A LIGHT WIND FAVORING THE SOUTHWEST AND SOUTH OVERNIGHT AND ON
SATURDAY MORNING IS FORECAST TO INCREASE TO AROUND 8 OR 10 KNOTS
FOR SATURDAY AFTERNOON.

OUTLOOK...
SUNDAY - MONDAY...SUB-VFR CONDITIONS EXPECTED IN AREAS OF SHOWERS
AND THUNDERSTORMS.

TUESDAY - WEDNESDAY...VFR.

&&

.MARINE...
A SOUTH TO SOUTHWEST WIND AT 10 TO 15 KNOTS EARLY THIS EVENING
SHOULD DIMINISH TO 5 TO 10 KNOTS OVERNIGHT.

THE HIGH PRESSURE SYSTEM WILL BE MOVING OFFSHORE AND A SLIGHTLY
STRONGER SYNOPTIC SCALE RETURN FLOW IS PREDICTED FOR SATURDAY. AS
IS TYPICALLY THE CASE, MODEL GUIDANCE OVER THE WATERS IS NORMALLY
OVERDONE IN CASES LIKE THIS AND WINDS AND SEAS WERE KEPT BELOW SCA
CRITERIA THRU THE DAY ON SATURDAY.

OUTLOOK...
SUNDAY...SUB-SCA EXPECTED WITH SCATTERED SHOWERS AND
THUNDERSTORMS.

MONDAY...SEAS MAY BUILD TO SCA LEVELS UNDER A STRENGTHENING
SOUTHWEST SURFACE FLOW.

TUESDAY - WEDNESDAY...SUB-SCA CONDITIONS EXPECTED.

&&

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

&&

$$

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





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