Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 061030
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
630 AM EDT MON JUL 6 2015

.SYNOPSIS...
LOW PRESSURE ACROSS NORTH CAROLINA WILL CONTINUE MOVING
NORTHWARD TODAY INTO THE DELMARVA ALONG A WARM FRONT. BY TUESDAY
NIGHT, THESE FEATURES WILL GIVE WAY TO HIGH PRESSURE LOCATED TO OUR
SOUTH. A COLD FRONTAL BOUNDARY THEN WILL PASS THROUGH THE REGION
LATER THIS WEEK WITH SEVERAL WAVES OF LOW PRESSURE POTENTIALLY
TRAVELING EASTWARD ALONG THE BOUNDARY. THE FRONTAL BOUNDARY WILL
STALL AND WEAKEN TO OUR SOUTH BY NEXT WEEKEND BEFORE ANOTHER WARM
FRONT COMES NORTHWARD INTO THE REGION EARLY NEXT WEEK

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630 AM VERSION: AREAS OF DOUBT CONTINUE TO BE TIMING AND AREAL EXTENT
OF SHOWERS/SPRINKLES EARLY TODAY AND THEN THIS AFTN, HOW MUCH CLEARING
AND MAX TEMPS ON THE DELMARVA PRIOR TO WHAT I THINK SHOULD BE
LARGE TSTM DEVELOPMENT.

MOCLOUDY AND HUMID WITH SCT SHOWERS OR DRIZZLE DRYING OUT TO THE
SW OF A KRDG-KACY LINE DURING THE 12Z TO 15Z TIME FRAME. THEN
HEATING UP A BIT UNDER THE CANOPY OF VARIABLE CLOUD COVER. HEAVY
SHOWERS AND SCT TSTMS DEVELOPING THIS AFTN OVER THE DELMARVA AND
SPREADING NNEWD, ESPECIALLY INTO E PA. THIS SUPPORTED IN PART BY
MODELED 1200J MLCAPE ON THE DELMARVA THIS AFTN.

TPHL AT 0945Z HAD SIGNS OF SMALL DROPLETS MOVING NWWD NEAR KILG
AND THIS APPEARED TO MATCH WITH UNEXPECTED SCTVBKN DECK NEAR 1000
FT THAT HAS BEEN FLIRTING WITH KPHL-KILG SINCE 08Z. SINCE 0945Z,
THOSE NWWD MOVING STRIATIONS OF MOISTURE HAVE NOT SINCE BEEN SEEN
IN THE TPHL LR IMAGERY.

QUITE A BIT OF UNCERTAINTY ON SHOWER TIMING TODAY LEAVING ME WITH
LOW CONFIDENCE ON THE RAIN DETAILS EXCEPT TO SAY THE LARGE PWAT OF
1.75 TO 2 INCHES SUGGESTS BRIEF TORRENTS OF POOR DRAINAGE FLOODING
RAIN POTENTIAL DELMARVA AND E PA TODAY, ESPECIALLY MID AFTN. NOT
IMPOSSIBLE FOR ISOLATED SVR ON THE DELMARVA THIS AFTN DESPITE LACK
OF CRITERIA 0-6KM 30KT BULK SHEAR. THE LOW LVL SHEAR IS SIGNIFICANT
INDICATING TO ME THAT TSTMS MIGHT DEVELOP SHALLOW MESOCYCLONE
SIGNATURES OVER THE DELMARVA THIS AFTN WITH STILL POTENTIAL FOR
ISOLATED 45 KT GUSTS. PLS SEE NC SVR REPORTS FROM YDY. ALSO TODAYS
SWODY1 FROM SPC.

WORDED TSTM HEAVY RAIN E PA AND DELMARVA AND ON THE DELMARVA ADDED
GUSTY WINDS.

TEMPS WERE A 50 50 BLEND OF THE 00Z/6 GFS/NAM MOS BLENDED WITH THE
NAM 2M TEMPS. THIS IS COOLER THAN WHAT WE HAD INDICATED FOR THE
PAST SVRL DAYS BUT THEN TOO WE TOO WE DIDNT THINK CLOUD AND SHOWERS.
SO THIS MONDAYS FCST IS GLOOMIER THAN PREVIOUSLY EXPECTED. ONE
SIGNIFICANT AREA OF DOUBT ON TEMPS IS THE DELMARVA, ESPECIALLY
TALBOT QUEEN ANNES/CAROLINE COUNTIES IN MD AND SUSSEX COUNTY DE
WHERE IT MAY PARTIALLY CLEAR AND PERMIT MORE HEATING THAN NOW
FCST.

WINDS...MAX GRADIENT WIND GUSTS SHOULD BE AROUND 15-18 MPH THIS
AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
WAA CONTINUES TONIGHT WITH THE WARM FRONTAL BOUNDARY LIFTING NORTHWARD
THROUGH OUR FCST AREA, POSSIBLY ACCOMPANIED BY CLUSTERS OF SHOWERS
AND ISOLATED HEAVY TSTMS, ESPECIALLY I95 WESTWARD. CONFIDENCE ON
WHERE IT RAINS AND WHEN IS BELOW AVG. HOWEVER WE DO NOTE MODELED
25 KT 700 AND 850 MB SPEED MAX`D OVER CHES BAY AROUND 06Z WHICH
SHOULD SUPPORT BANDS OF SHOWERS IN E PA. OUR FCST POPS TONIGHT
APPEAR TOO LOW AND RAISED ABOUT 10 PCT IN THE 630 AM FCST. MAY
NEED A FURTHER RAISE IN LATER UPDATES.

PATCHES OF STRATUS/FOG ARE LIKELY LATE TONIGHT AND ITS CONCEIVABLE
A FEW LOCATIONS WILL DROP TO 1/2MI IN FOG AFTER MIDNIGHT,
ESPECIALLY I-78 NORTHWARD.

TEMPS WERE MOSTLY THE WARMER 00Z/6 GFS MAV MOS AND ABOVE NORMAL...BY
5 TO 10 DEGREES!

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
TUESDAY AND TUESDAY NIGHT: A SHORTWAVE IS LIKELY TO BE THE FOCUS
OF SOME SCATTERED SHOWERS EARLY IN THE DAY ACROSS EASTERN PA,
DEPARTING THE REGION BY AFTERNOON. ANY FOG ON LAND SHOULD BURN OFF
BY MID-MORNING GIVEN INCREASING WINDS. THE GFS AND NAM SOUNDINGS ARE
BOTH SHOWING ENOUGH MOMENTUM TRANSFER TO SUGGEST 15-20 MPH
AFTERNOON SOUTHWESTERLY WIND GUSTS. WE SHOULD SEE SOUTHWESTERLY
FLOW ON THE BACKSIDE OF THE HIGH PRESSURE SYSTEM AS WELL. THIS
WILL LEAD TO CONTINUED WARM AND HUMID AIR BEING ADVECTED INTO THE
REGION. AN ABSENCE OF ANY TRIGGER FOR SHOWERS AND STORMS IS
LIKELY TO BE PRESENT BUT THE PRESENCE OF HEAT/HUMIDITY WILL LEAD
TO A UPTICK IN INSTABILITY. THIS MAY BE ENOUGH TO DEVELOP A
ISOLATED AFTERNOON SHOWER OR STORM. 925 MB TEMPERATURES ARE
LIKELY TO BE AROUND 20C EQUATING TO SURFACE HIGH TEMPERATURES
PUSHING 90. MUGGIER/WARMER OVERNIGHT TEMPERATURES ARE ALSO LIKELY
DUE TO THE AIRMASS ADVECTING IN.

WEDNESDAY AND WEDNESDAY NIGHT: A COLD FRONTAL BOUNDARY BEGINS TO
ENTER THE PICTURE WEDNESDAY AFTERNOON AND EVENING GIVING US THE
TRIGGER MISSING ON TUESDAY FOR A MORE WIDESPREAD SHOWER AND
THUNDERSTORM CHANCE. WITH THE HIGHER CHANCES OF RAIN, HIGH
TEMPERATURES MAY NOT REACH THE FULL POTENTIAL DUE TO THE PRESENCE
OF MORE CLOUDS, MODELED 925 MB TEMPS AROUND 25C WITH THE ABUNDANT
ADVECTION WOULD GIVE US MID 90`S FOR HIGHS. SLOWER TIMING OF THE
FRONT WOULD LEAD TO A HOTTER DAY AND A FASTER FRONTAL PASSAGE OR
MORE IN THE WAY OF DEBRIS CLOUDS WOULD KEEP WELL UNDER THOSE
VALUES. WENT WARMER THAN MET/MAV AND ECMWF MOS GIVEN THEY MAY SLOW
TO SHOW THE ADVECTION POTENTIAL BUT DIDN`T WANT TO DEVIATE TO
MUCH GIVEN SOME UNCERTAINTY WITH WEDNESDAY`S HIGHS. INSTABILITY IS
CURRENTLY MODELED AT OVER 1000 J/KG IN TERMS OF SURFACE AND MIXED
LAYER ON THE NAM AND GFS WITH STEEP LOW AND MID- LEVEL LAPSE
RATES. HOWEVER 0-6 KM BULK SHEAR IS VERY SMALL LESS THAN 20 KNOTS.
THIS WOULD IMPLY ENOUGH INSTABILITY IS PRESENT TO DEVELOP
THUNDERSTORMS IN ASSOCIATION WITH THE COLD FRONT BUT THE OVERALL
PROBABILITIES FOR STORM ORGANIZATION AND DEVELOPMENT INTO MORE
THAN ISOLATED STRONG TO SEVERE STORMS ARE LOW. PW VALUES ARE
ELEVATED THOUGH ABOVE 2 INCHES, SO THE POTENTIAL EXISTS FOR HEAVY
DOWNPOURS RESULTING IN POOR DRAINAGE FLOODING. HIGHEST CHANCES
AFTERNOON AND EVENING FOR STORMS ON WEDNESDAY.ONCE AGAIN MODELED
SOUNDINGS FROM THE NAM AND GFS SHOW THE POTENTIAL FOR SOME 15 MPH
WIND GUSTS FROM THE WEST-SOUTHWEST IN THE AFTERNOON HOURS.

THURSDAY THROUGH FRIDAY NIGHT: THE FRONTAL BOUNDARY WILL LIKELY
STALL JUST TO OUR SOUTH IN RESPONSE TO A MID-LEVEL RIDGE OVER THE
SOUTHEAST UNITED STATES. COOLER TEMPERATURES ARE LIKELY WITH A
MORE NORTHERLY WIND. THE HIGHEST CHANCE OF LINGERING
SHOWERS/STORMS WITH ANY WAVE OF LOW PRESSURE IS FORECASTED FOR
THURSDAY, GIVEN MORE UNCERTAINTY IN THE FRONTAL LOCATION ON
FRIDAY. EXTENSIVE CLOUDS EITHER DAY COULD KEEP TEMPERATURES LOWER
THAN FORECASTED EACH DAY. TIGHT CLUSTER WITH ENSEMBLE GUIDANCE IN
THIS PERIOD AND WAS LEANED ON QUITE A BIT IN THIS PERIOD FOR THE
FORECAST.

SATURDAY THROUGH SUNDAY NIGHT: THE FRONT LOOKS TO WEAKEN TO OUR
SOUTH, ENOUGH FOR THIS PERIOD TO LEAN DRIER ON SATURDAY. HIGH
PRESSURE SYSTEMS TRAVERSING NORTH OF OUR REGION MAY ALLOW FOR A
WIND DIRECTION CHANGE TO MORE SOUTHERLY BY THE END OF NEXT
WEEKEND POSSIBLY YIELDING A RETURN OF WARMER AND MORE HUMID
CONDITIONS WITH LOW CHANCES OF SHOWERS AND STORMS BY LATE SUNDAY.
TIGHT CLUSTER WITH ENSEMBLE GUIDANCE IN THIS PERIOD AND WAS LEANED
ON QUITE A BIT IN THIS PERIOD FOR THE FORECAST.

&&

.AVIATION /10Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

PRIOR TO 12Z...VFR CIGS MAINLY AOA 7000 FT. THERE IS SOME SIGN OF
DRIZZLE MOVING - DEVELOPING NWWD ON TPHL VCNTY KILG WHICH SEEMS
TO MATCH NICELY WITH SCTVBKN NEAR 1000 FT THAT HAS BEEN FLIRTING
WITH KPHL AND KILG SINCE 08Z. LIGHT WIND. SOME MID DECK SHOWERS
ARE POSSIBLE CLOSER TO 12Z NEARING KILG/KMIV.

TODAY AFTER 12Z...ANY CIGS AOB 1000 FT SHOULD DISSIPATE BY 14Z
OTHERWISE MAINLY VFR CIGS AOA 5000 FT. SCT DRYING-DYING SHOWERS
MOVING INTO THE TAF VCNTY EXCEPT PROBABLY NOT AT KTTN AND KABE
THIS MORNING. PLS SEE TAFS FOR DETAILS.

THIS AFTERNOON SHOULD SEE HEAVIER SHOWERS AND THUNDERSTORMS DEVELOP
OVER THE DELMARVA AND MOVE NNE INTO THE KILG-KPHL-KRDG AREA BY MID
OR LATE AFTN. THOSE COULD EASILY GENERATE BRIEF IFR CONDITIONS IN
HEAVY RAIN WITH WIND GUSTS 30-35 KT. ISOLATED SVR STORM POSSIBLE
DELMARVA.

OTHERWISE NON TSTM WINDS WILL TEND SOUTHEAST TODAY WITH AFTERNOON
GUSTS AROUND 15 KT.

NARRE IS MODELING NWWD DEVELOPING ST/SC ONTO THE DE COAST LATE
THIS AFTN AND THAT MAY NEED MORE INFLUENCE ON THE FCST THAN
CURRENTLY POSTED.

TONIGHT...CONDITIONS POSSIBLY LOWERING TO MVFR OR IFR IN LOW CLOUDS,
HAZE AND FOG ESPECIALLY DURING THE LATE NIGHT AND EARLY MORNING
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS, ESPECIALLY EASTERN PA.

OUTLOOK...

TUESDAY AND TUESDAY NIGHT: VFR. SOUTHERLY WINDS UNDER 10 KNOTS AND
GUSTS AT OR UNDER 15 KNOTS. ANY THUNDERSTORM RESTRICTION TO MVFR
OR IFR LOOKS ISOLATED.

WEDNESDAY AND WEDNESDAY NIGHT: POTENTIAL MVFR AND IFR RESTRICTIONS IN
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING. WEST-
SOUTHWEST WIND GUSTS AT OR UNDER 15 KNOTS.

THURSDAY THROUGH FRIDAY NIGHT: MAINLY VFR, A FEW LOWER MVFR OR
IFR RESTRICTIONS POSSIBLE IN ISOLATED TO SCATTERED SHOWERS AND
STORMS. NORTHERLY WINDS UNDER 10 KNOTS.

&&

.MARINE...
NO MARINE HEADLINES THROUGH TONIGHT.

OUTLOOK...

SUB-SCA WINDS AND SEAS EXPECTED. ANY WIND GUSTS LOOK TO
REMAIN BELOW 20 KNOTS, MORE SOUTHWESTERLY THROUGH WEDNESDAY THEN
MORE NORTHERLY THURSDAY AND FRIDAY. SEAS MAY REACH FOUR FEET ON
WEDNESDAY. THE HIGHEST CHANCE OF THUNDERSTORMS IS WEDNESDAY
AFTERNOON AND EVENING.

&&

.RIP CURRENTS...
WE ARE FORECASTING LOW RISK TODAY WITH A 2 TO 3 FOOT 7 SECOND
SOUTHEAST SWELL AND A SOUTHEAST WIND INCREASING TO AROUND 10 MPH
THIS AFTERNOON. THIS SHOULD RESULT IN A LOW OR LOW ENHANCED RISK
FOR THE FORMATION OF DANGEROUS RIP CURRENTS. THE TIDE WILL BE
GOING OUT THIS AFTERNOON WHICH ALSO INCREASES THE RISK OF THE
FORMATION OF DANGEROUS RIP CURRENTS.

ONE OTHER NOTE: SST`S ARE GENERALLY ABOVE NORMAL, MAKING IT MORE
ATTRACTIVE TO BE IN THE WATER.

OUR 1015 AM BEACH PATROL CONFERENCE CALL WILL RECHECK THE
CONDITIONS UPON WHICH THIS FORECAST WAS BASED.

BEACH BATHYMETRY AND TIDE CYCLE PLAY A ROLE IN THE VARIABILITY OF
RIP CURRENT FORMATION AND ASSOCIATED STRENGTHS. ITS IMPOSSIBLE TO
DETAIL THE LOCATIONS OF VARIABILITY BUT WE DO KNOW THAT OUTGOING
TIDES CAN ENHANCE THE DANGERS OF RIP CURRENTS.

ALSO...LOW RISK DOES NOT MEAN      NO RISK.

THERE ARE MANY SWIMMERS THAT HAVE LITTLE OR NO EXPERIENCE SWIMMING
IN THE OCEAN. ITS FAR DIFFERENT THAN IN THE POOL OR LAKE. THE MAJORITY
OF INLAND SWIMMERS HITTING THE BEACH FOR FUN AND SWIMMING PROBABLY
HAVENT BEEN TRAINED IN RECOGNIZING RIP CURRENTS NOR ARE THEY
PREPARED FOR THE DANGERS.

AS A BEST PRACTICE, PLEASE SWIM IN THE PRESENCE OF LIFEGUARDS
WHERE RESPONSE TO A LIFE THREATENING RIP CURRENT IS VIRTUALLY
INSTANT. SWIMMING AT NON LIFEGUARDED LOCATIONS (PIERS/JETTIES) OR
WHEN THE GUARDS ARE NOT ON DUTY RAISES THE POTENTIAL OF A FATAL
EPISODE SINCE IT TAKES PRECIOUS MINUTES FOR RESPONSE TEAMS TO
ARRIVE.

BE SAFE AND SWIM SMART, WITHIN THE WATCHFUL VISION OF YOUR
LIFEGUARDS...TRAINED TO LOOK OUT FOR YOUR SAFETY. THANK YOU!

&&

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

&&

$$
SYNOPSIS...GAINES
NEAR TERM...DRAG 631
SHORT TERM...DRAG/NIERENBERG 631
LONG TERM...GAINES
AVIATION...DRAG/GAINES 631
MARINE...DRAG/GAINES
RIP CURRENTS...631



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