635
FXUS61 KPHI 160037
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
837 PM EDT MON JUL 15 2019
SYNOPSIS
HIGH PRESSURE WILL BUILD OFFSHORE TONIGHT. A WEAK WARM FRONT LIFTS
NORTH ON TUESDAY, AND THEN THE REMNANTS OF BARRY WILL AFFECT THE
REGION WEDNESDAY NIGHT INTO THURSDAY. A COUPLE WEAK AND DRY COLD
FRONTS WILL PASS NEAR THE REGION OVER THE WEEKEND.
NEAR TERM /UNTIL 6 AM TUESDAY MORNING/
630 PM...WITH THE CURRENT FORECAST ON TRACK, MADE ONLY VERY
MINOR ADJUSTMENTS TO THE TEMPERATURE/DEWPOINT TEMPERATURE GRIDS
TO MATCH CURRENT OBSERVATIONS. HIGH PRESSURE WILL MAINTAIN
CONTROL OVER THE AREA THROUGH TONIGHT BRINGING MAINLY CLEAR
SKIES, LIGHT WINDS, SEASONABLE TEMPERATURES, AND FAIRLY
COMFORTABLE HUMIDITY LEVELS. BY LATER TONIGHT EXPECT LOWS MAINLY
IN THE 60S...RANGING FROM AROUND 60 OVER THE SOUTHERN POCONOS
TO THE UPPER 60S TO AROUND 70 IN THE URBAN CORRIDOR.
SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/
HIGH PRESSURE WILL WEAKEN OVER THE AREA TUESDAY AS ITS CENTER
SHIFTS OFFSHORE. THIS WILL ALLOW A LIGHT SW FLOW TO SET UP WITH
BOTH TEMPERATURES AND HUMIDITY LEVELS STARTING TO CREEP UP A BIT
COMPARED TO MONDAY. HIGHS SHOULD BE MAINLY IN THE UPPER 80S TO
LOW 90S EXCEPT A BIT COOLER RIGHT ALONG THE COAST AS WELL AS THE
SOUTHERN POCONOS. SKIES WILL BE MAINLY CLEAR WITH JUST SOME
SCATTERED CU DEVELOPING IN THE AFTERNOON AND SOME HIGH CLOUDS
MOVING IN FROM THE WEST LATE DAY. THERE'S THE OUTSIDE CHANCE OF
SOME ISOLATED LATE DAY SHOWERS/STORMS OVER PARTS OF EASTERN PA
INTO THE DELMARVA BUT FORCING AND DEEP MOISTURE WILL BE LIMITED
SO WE KEPT POPS AT 20 PERCENT OR LOWER.
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/
OVERVIEW: REMNANTS OF BARRY WILL MOVE THROUGH THE REGION
WEDNESDAY NIGHT AND THURSDAY FOLLOWED BY A PERIOD OF EXCESSIVELY
HOT WEATHER ACROSS THE MID-ATLANTIC.
WEDNESDAY...THE HOT AND HUMID AIR RETURNS TO THE MID-ATLANTIC AS THE
REMNANTS OF BARRY MAKE THEIR WAY TOWARDS THE REGION. STRONG MOISTURE
ADVECTION IN THE DEEPENING SOUTH TO SOUTHWEST FLOW WILL RAISE THE
DEW POINTS BACK UP INTO THE LOW TO MID 70S GIVING US THAT GROSS
STICKY FEELING. HIGH TEMPERATURES WILL AGAIN RISE INTO THE LOWER 90S
THROUGH MUCH OF THE REGION. HEAT INDEX VALUES WILL RISE, ESPECIALLY
THROUGH THE URBAN CORRIDOR, WITH MANY AREAS SEEING VALUES AROUND 100-
105. WITH INCREASING MOISTURE AND GROWING INSTABILITY, WE SHOULD SEE
SOME THUNDERSTORMS DEVELOP THROUGH THE AFTERNOON AND WITH PWATS IN
EXCESS OF 2.0", TORRENTIAL RAINFALL WILL BE A CONCERN. EXPECT THE
SHOWERS AND THUNDERSTORMS TO CONTINUE INTO WEDNESDAY NIGHT WITH
LITTLE RELIEF TEMPERATUREWISE WITH EXTENSIVE CLOUD COVER AND LOWS
REMAINING IN THE 70S.
THURSDAY...HEAVY RAIN CONTINUES AS THE REMNANT LOW FROM BARRY MOVES
ACROSS THE REGION. DUE TO EXTENSIVE CLOUD COVER ACROSS THE REGION,
WE WON'T WARM AS EFFICIENTLY AS WE DO ON WEDNESDAY SO EXPECT HIGHS
TO BE A FEW DEGREES COOLER. UNFORTUNATELY, THE DEW POINTS REMAIN IN
THE 70S SO THE MUGGINESS WILL REMAIN AND HEAT INDEX VALUES WILL
LIKELY RISE BACK TO AROUND 100. AGAIN, OVERNIGHT LOWS WILL REMAIN UP
AND IN THE LOW TO MID 70S.
FRIDAY THROUGH SUNDAY...THE HEAT IS ON AND WILL CONTINUE THROUGH THE
WEEKEND. SURFACE HIGH PRESSURE WILL SITUATE ITSELF OVER THE WESTERN
ATLANTIC WITH A SURFACE TROUGH ACROSS THE EASTERN SEABOARD. IN THE
MID AND UPPER LEVELS, WE WILL SEE A LARGE RIDGE SPREAD ACROSS THE
MID-ATLANTIC, WHICH WILL HELP IN FACILITATING AN INCREASINGLY HOT
AIRMASS THROUGH THE WEEKEND. WHILE THE NUMBERS MAY VARY ACROSS THE
MODELS, THE 850MB TEMPERATURES LOOK TO RISE AROUND 22-23C EACH DAY,
WHICH TRANSLATES TO UPPER 90S TO AROUND 100 DEGREES AT THE SURFACE,
ESPECIALLY FOR FRIDAY AND SATURDAY. WITH DEW POINTS IN THE MID TO
UPPER 70S, IT WILL FEEL OPPRESSIVE AND IT IS LOOKING INCREASINGLY
LIKELY THAT HEAT HEADLINES WILL BE NEEDED FOR THIS PERIOD. OVERNIGHT
LOWS WILL REMAIN IN THE UPPER 70S TO AROUND 80, ESPECIALLY THROUGH
THE URBAN CORRIDOR, PROVIDING NO RELIEF FROM THE HEAT. THE HEAT
STARTS TO BREAK A BIT FOR SUNDAY AS THE UPPER/MID RIDGE STARTS TO
SHIFT TOWARDS THE EAST BUT BOTH THE GFS AND ECMWF HOLD ONTO THE
HIGHER 850MB VALUES THROUGH SUNDAY SO ANTICIPATE THAT THE EXCESSIVE
HEAT WILL CONTINUE THROUGH THE END OF THE WEEKEND. ADDITIONALLY, WE
MAY GET BRIEF RELIEF FROM SHOWERS AND THUNDERSTORMS THROUGH EACH
AFTERNOON/EVENING AS THE AIRMASS REMAINS FAIRLY UNSTABLE AND
EXCEPTIONALLY MOIST. THE MISSING FACTOR IS THE TRIGGER AND THERE
JUST MAY BE ENOUGH LIFT ALONG THE SURFACE TROUGH TO GET US GOING
EACH DAY. THE CONVECTION WILL LARGELY BE DIURNALLY DRIVEN SO AS WE
HEAD PAST SUNSET EACH NIGHT, IT SHOULD DIMINISH IN COVERAGE. WITH
SUCH EXCESSIVE MOISTURE ACROSS THE REGION YOU CAN EXPECT THAT AND
SHOWER OR THUNDERSTORM THAT DEVELOPS WILL HAVE TORRENTIAL RAINFALL.
MONDAY...THE HEAT MAY FINALLY BREAK SOME FOR MONDAY AS THE MODELS
ARE SHOWING THE UPPER/MID RIGHT SHIFTING TO THE EAST AND A WEAK
BOUNDARY PUSHING IN FROM THE WEST. A SHIFT TO A MORE NORTHWESTERLY
FLOW, ALBEIT WEAK, MAY BE ENOUGH TO CUT THE HUMIDITY LEVELS AND DROP
THE HEAT INDEX VALUES BACK DOWN TO THE UPPER 90S TO AROUND 100.
AVIATION /01Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON...VFR/SKC-FEW250. WINDS MAINLY W- SW 5-10 KT
EXCEPT AFTERNOON SEA BREEZES WILL RESULT IN S- SE WINDS AT KACY
AND POSSIBLY KMIV.
TONIGHT...VFR/SKC. LGT/VRB WINDS.
TUESDAY...MOSTLY VFR CONDITIONS, WITH A SLIGHT CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS AT RDG AND ABE.
SOUTHWESTERLY WINDS 5 TO 10 KT.
OUTLOOK...
WEDNESDAY...MAINLY VFR CONDITIONS EXPECTED. MVFR OR LOWER IN SHOWERS
AND THUNDERSTORMS. SOUTH TO SOUTHWEST WINDS AROUND 5 TO 10 KNOTS.
THURSDAY...MVFR OR LOWER IN SHOWERS AND THUNDERSTORMS WITH PERIODS
OF VFR POSSIBLE. SOUTH TO SOUTHWEST WINDS AROUND 5 TO 10 KNOTS.
FRIDAY AND SATURDAY...MAINLY VFR CONDITIONS EXPECTED. MVFR OR LOWER
POSSIBLE IN SHOWERS AND THUNDERSTORMS, MAINLY DURING THE
AFTERNOON/EVENING. WEST TO SOUTHWEST WINDS AROUND 5 TO 10 KNOTS.
EXCESSIVE HEAT INDEX VALUES EXPECTED.
MARINE
THROUGH TONIGHT...SUB-SCA CONDITIONS. WINDS MAINLY S/SE THIS
AFTERNOON AROUND 10 KNOTS OR LESS BECOMING SOUTHWEST TONIGHT.
SEAS 2-3 FEET ON THE OCEAN AND 1-2 FEET ON DE BAY.
TUESDAY...SUB-SCA CONDITIONS CONTINUING WITH SW WINDS 5-10 KNOTS
BECOMING SOUTHERLY 10-15 KNOTS BY LATE DAY. SEAS REMAIN AROUND 2
FT.
OUTLOOK...
WEDNESDAY AND THURSDAY...SUB-SCA CONDITIONS EXPECTED. SOUTH TO
SOUTHWEST WINDS AROUND 10 TO 15 KNOTS. SEAS AROUND 2 TO 4 FEET.
FRIDAY AND SATURDAY... SUB-SCA CONDITIONS EXPECTED. SOUTHWEST WINDS
AROUND 10 TO 15 KNOTS. SEAS AROUND 2 TO 3 FEET.
RIP CURRENTS...
ON TUESDAY, THE RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS
COULD INCREASE TO MODERATE, ESPECIALLY FOR THE NORTHERN AND
CENTRAL NJ SHORE WHERE WINDS WILL BE SLIGHTLY STRONGER AND WAVES
UP TO 3 FEET ARE POSSIBLE. AT THIS POINT, THINK THAT THE RISK
FOR THE SOUTHERN NJ SHORE AND FOR THE DE BEACHES WILL REMAIN
LOW. HOWEVER, IF THE WINDS ARE STRONGER FURTHER SOUTH OR IF
WAVES ARE HIGHER THAN THE CURRENTLY FORECAST 2 FEET, THE RISK
MAY INCREASE TO MODERATE IN THESE AREAS AS WELL.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...JOHNSON
NEAR TERM...FITZSIMMONS/MIKETTA
SHORT TERM...FITZSIMMONS
LONG TERM...MEOLA
AVIATION...FITZSIMMONS/MEOLA
MARINE...FITZSIMMONS/JOHNSON/MEOLA
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