000
FXUS61 KPHI 211855
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
255 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEASTERN UNITED STATES
COAST THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL MOVE FROM THE
SOUTHERN PLAINS TO SOUTHEASTERN CANADA THROUGH THURSDAY AND BRING
A COLD FRONT THROUGH THE REGION LATE THURSDAY INTO FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST FOR THE HOLIDAY WEEKEND
THIS HIGH WILL THEN GRADUALLY MOVE OFFSHORE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH 6 AM WEDNESDAY MORNING/...
ANY LINGERING SHOWERS/TSTMS ACROSS THE NORTHERN AREAS WILL DISSIPATE
THIS EVENING WITH THE LOSS OF HEATING. A FEW DOWNPOURS MAY OCCUR
WITH THE ACTIVITY EARLY. SKIES WILL BE PARTLY TO MOSTLY CLOUDY
EARLY...THEN TRANSITION BACK TO A LOW OVC ALONG WITH AREAS OF FOG
AGAIN TONIGHT. CONDITIONS WILL PROBABLY REMAIN ABOVE DENSE FOG
ADVISORY CRITERIA...SO WE HAVE NOT ISSUED THAT ATTM. IT WILL REMAIN
WARM AND HUMID AGAIN TONIGHT WITH LOWS IN THE LOW/MID 60S NORTH AND
MID/UPPER 60S SOUTH. WINDS LIGHT MOSTLY FROM THE SW.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY EVENING/...
WEDNESDAY WILL HAVE WEATHER SIMILAR TO TODAY. PLENTY OF CLOUDS/FOG IN
THE MORNING AND THE CHC FOR SHOWERS/TSTMS DURING THE AFTERNOON. THIS
ACTIVITY WILL PROBABLY BE FOUND ACROSS MOST AREAS...UNLIKE TDY WHERE
IT WAS RESTRICTED TO THE NORTH. WE WILL CARRY POPS IN THE CHC RANGE
FOR NOW. THE SPC HAS PLACED THE SLGT RISK FOR TSTMS TO THE WEST OF
OUR AREA...SO WE WILL WATCH FOR UPDATED OVERNIGHT. HIGHS WILL BE
VERY WARM AGAIN WED WITH TEMPS IN THE MID 80S IN MOST AREAS (EXCEPT
ALONG THE SHORE...WHERE READINGS IN THE UPPER 70S TO LOW 80S MAY
OCCUR).
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE AREA OF HIGH PRESSURE WILL REMAIN OFF THE ATLC CST WED NIGHT
AND THU AND SWLY FLOW WILL CONTINUE WHICH WILL KEEP WARM WX OVER
THE AREA. HOWEVER, BY THU, AN AREA OF LOW PRESSURE WILL MOVE INTO
SERN CANADA. THE CDFNT ASSOCD WITH THIS LOW WILL CROSS THE REGION
THU NIGHT. THIS PD LOOKS TO TO BE THE WETTEST WITH SHOWERS, TSTMS
AND PSBLY SOME HEAVY RAIN. ITS A BIT TOO EARLY TO BE CERTAIN ABOUT
ANY SEVER WX POTENTIAL. IT WILL BE DEPENDENT ON DAYTIME HEATING
AND OTHER FACTORS. HOWEVER, IT COULD BE MITIGATED BY THE FACT THAT
THE FRONT WILL BE COMING THROUGH AFTER SUNSET. THE 21/12Z GFS IS
THE SLOWEST MDL CLEARING THINGS OUT ON FRI AND TRIES TO DEVELOP A
WAVE ALG THE FRONT. NONE OF THE OTHER MDLS HAVE THIS FEATURE, SO
AM NOT INCLINED TO GO ALONG FOR NOW. FRI, ESPECIALLY LATER FRI,
SHOULD SEE IMPROVING WX AND BY SAT A LARGE AREA OF HIGH PRESSURE
WILL PUSH INTO THE MIDWEST FROM CANADA WAND WILL SLOWLY SLIDE EWD
THRU THE HOLIDAY WEEKEND.
THE PGRAD BETWEEN THE BUILDING HIGH AND THE DEPARTING LOW OVER THE
CANADIAN MARITIMES WILL KEEP A DECENT NWLY FLOW OVER THE AREA ON
SAT, WITH WEAKENING FLOW AS THE HIGH MOVES IN ON SUN. SO, AT THIS
POINT, THE WEEKEND LOOKS PREDOMINANTLY DRY, ALBEIT COOL FOR LATE
MAY AND WITH A BRISK NW WIND, IT WILL FEEL COOLER ON SAT.
TEMPS LOOK TO BE WARMEST ON THU, WITH TEMPS AROUND 80 OR INTO THE
80S. THEN BEHIND THE FRONT MOST LOCATIONS WILL BE AROUND 70 OR
INTO THE LOWER 70S FOR THE REMAINDER OF THE PD. SAT LOOKS TO BE
THE COOLEST DAYS, WITH MANY LOCATIONS HOVERING IN THE MID/UPPER 60S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
IT HAS BEEN TAKING A LONG TIME FOR THE PATCH OF ST ACROSS
MIV-PHL-ILG TO FINALLY DISSIPATE...BUT IT APPEARS THAT IT WILL BY
MID AFTERNOON. VFR CONDITIONS EXPECTED INTO THE EVENING...BEFORE A
RETURN BACK TO LOW MVFR/OR IFR CONDITIONS AGAIN TONIGHT. A FEW SCT
SHOWERS OR MAYBE A TSTM COULD AFFECT KABE LATER THIS AFTERNOON...BUT
THE PROB LOOKS TOO LOW TO INCLUDE IN THE TAFS ATTM. AMDS POSSIBLE.
WINDS SHOULD STAY MOSTLY SW INTO THE EVENING AND THEN GO MOSTLY
LIGHT S OVERNIGHT. WED...A SLOW RETURN TO VFR BY MID-MORNING THEN
SCT SHOWERS/TSTMS POSSIBLE DURING THE AFTERNOON.
OUTLOOK...
WED NIGHT THROUGH THU NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE IN ANY SHOWERS AND THUNDERSTORMS OR PDS OF
HEAVY RAIN. WIND WILL SHIFT FROM SW TO NW BEHIND CFP LATE WED
NIGHT/EARLY THU MRNG. HIGH CONFIDENCE ON THE OVERALL DETAILS. LOW
CONFIDENCE ON THE FACT THAT ALL SITES WILL SEE MVFR/IFR AND
TIMING.
FRI...MAINLY VFR WITH A CHANCE OF SHOWERS MAINLY IN THE MORNING.
HIGH CONFIDENCE.
SAT-SUN...VFR CONDITIONS EXPECTED. A BRISK NW WIND ON SAT OF 15-20
KT. HIGH CONFIDENCE.
&&
.MARINE...
WINDS HAVE BEEN MOSTLY SW/S ACROSS THE WATERS TODAY WITH SPEEDS
MOSTLY 10 TO 15 KTS. SEAS HAVE BEEN MOSTLY AROUND 3 FT ON THE OCEAN
AND 1 TO 2 FT OVER THE DEL BAY. CONDITIONS SHOULD REMAIN SUB-SCA
TONIGHT AND APPROACH SCA LATER WEDNESDAY. WINDS WILL INCREASE
WED...BUT WITH THE WARMER AIR AND COOLER SEAS...THE WINDS/WAVE
GUIDANCE MAY BE TOO HIGH. WE OPT TO KEEP THE SEAS AT 3 TO 4 FT FOR
WED AND HOLD THE WINDS BELOW SCA FLAG LEVELS. A FEW G 20-25 ARE NOT
OUT OF THE QUESTION LATER WED. SCAT SHOWERS/TSTMS EXPECTED WED.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WED NIGHT THROUGH
THU. AS THIS FLOW STRENGTHENS WITH A CDFNT APPROACHING FROM THE W
ON THU, WINDS AND SEAS WILL GRADUALLY INCREASE. THEREFORE, SEAS
AND WIND COULD BE AOA SCA CRITERIA BY THE START OF THE OUTLOOK PD. A
SMALL CRAFT ADVISORY MAY BE NEEDED FOR THIS PD ON THE OCEAN FRONT.
HOWEVER, WITH VERY WARM AIR OVER THE RELATIVELY COOL OCEAN AND
WAVE WATCH OVERDOING HEIGHTS OF LATE, HAVE DECIDED NOT TO POST
ANYTHING ATTM. THERE WILL ALSO BE SOME SHWRS/TSTMS WED NIGHT INTO
THU ALG AND AHEAD OF THE CFP.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SCA CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW CRITERIA THROUGH
THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
000
FXUS61 KPHI 211525
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1125 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED JUST OFF THE SOUTHEASTERN UNITED
STATES COAST THROUGH THURSDAY. LOW PRESSURE WILL APPROACH FROM THE
WEST, PASSING TO OUR NORTH, AND WILL DRAG A COLD FRONT THROUGH THE
REGION LATE THURSDAY INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD IN
FROM THE WEST FOR THE WEEKEND BEFORE MOVING OFFSHORE LATER SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
VARIOUS ADJUSTMENTS FOR THE ESTF WITH CLOUDS STUBBORN ACROSS THE
DELMARVA AND LOWER DEL VALLEY WITH SUNSHINE MUCH MORE ABUNDANT
ACROSS THE LEHIGH VALLEY AND THE NRN HALF OF NJ. TEMP TRENDS HAVE
BEEN ADJUSTED ACCORDINGLY WITH HIGHER READINGS NORTH/WEST AND
SLOWER RISES SOUTH/EAST. THERE IS A CHC FOR SHOWERS/TSTMS THIS
AFTERNOON...ESPECIALLY NORTH/WEST WITH BETTER INSTABILITY AND A
WEAKER CAP EXPECTED. UPDATED PUBLIC PRODUCTS WILL BE SENT SHORTLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SYNOPTIC SITUATION OVERNIGHT DOES NOT CHANGE MUCH FROM THE
DAYTIME. A STRONGER SHORT WAVE/VORT MAX ALOFT IS FORECAST TO
APPROACH THE AREA OVERNIGHT, AT THE SAME TIME A WEAK SURFACE TROUGH
MAY MOVE ACROSS THE AREA. THERE COULD STILL BE SOME INSTABILITY
OVERNIGHT, WHICH COULD LEAD TO THE CHANCE FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA. WE LEFT FOG OUT OF THE
FORECAST OVERNIGHT AS THERE MAY BE ENOUGH MIXING TO PREVENT MUCH OF
THE DENSER FOG FROM DEVELOPING. A BLEND OF THE MAV/MET MOS WAS TAKEN
FOR OVERNIGHT LOWS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE DOMINATES OUR WEATHER OVER THE NEXT SEVERAL DAYS AS IT
SETS UP SHOP OVER THE SOUTHWESTERN ATLANTIC. WITH THE HIGH TO OUR
SOUTHEAST, WE WILL SEE A SOUTHWESTERLY FLOW CONTINUE ACROSS THE
REGION. THIS SOUTHWEST FLOW WILL ADVECT WARM AND MOIST AIR TO OUR
AREA AND WE WILL REMAIN ABOVE NORMAL FOR TEMPERATURES THROUGH AT
LEAST MID WEEK. WITH ALL THAT MOIST, WARM AIR, WE WILL ALSO START TO
DESTABILIZE. THIS WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH THE WEEK, MAINLY IN THE AFTERNOON AFTER
SUFFICIENT DAYTIME HEATING HAS OCCURRED AND CONVECTIVE TEMPERATURES
HAVE BEEN REACHED.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST ON THURSDAY, WITH
THE CENTER PASSING OFF TO OUR NORTH. THE ATTACHED COLD FRONT IS
FORECAST TO MOVE THROUGH OUR AREA THURSDAY INTO FRIDAY, MOST LIKELY
LATER IN THE DAY THURSDAY INTO EARLY FRIDAY. THE LATEST MODEL
GUIDANCE HAS SLOWED DOWN THE FRONTAL PASSAGE AND WITH LITTLE SUPPORT
OVERALL, WE HAVE OPTED TO KEEP THE FORECAST LARGELY THE SAME AND
LEAN A BIT MORE ON THE PROGRESSIVE SIDE.
THE FRONT PUSHES THROUGH AND OFFSHORE BY FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT, BRINGING IN SOME COOLER AND
DRIER AIR FOR THE HOLIDAY WEEKEND. THE MODELS HINT AT A
SHORTWAVE MOVING THROUGH THE MID LEVELS LATE SATURDAY OR SUNDAY WITH
A LIGHT SHOWER POSSIBLE. THE AIR LOOKS LIKE IT MIGHT BE TOO DRY FOR
ANYTHING TO MAKE IT TO THE SURFACE AND WE HAVE KEPT THE HOLIDAY
WEEKEND POP FREE.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CIGS/VSBYS ARE NOW DEVELOPING ACROSS THE TAF SITES. THE LOW
CLOUDS/FOG WILL BURN OFF THROUGH THE MID MORNING HOURS, AND
CONDITIONS WILL EVENTUALLY BECOME VFR. THERE IS A CHANCE FOR SOME
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON, BUT
CONFIDENCE IN THEM HITTING A PARTICULAR TAF SITE IS LOW, SO THEY
WERE LEFT OUT OF THE FORECAST FOR THE TIME BEING.
ANOTHER ROUND OF LOW CLOUDS/FOG IS POSSIBLE AGAIN TUESDAY NIGHT.
HOWEVER, THERE IS ALSO THE POSSIBILITY FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS OVERNIGHT AS WELL. CONFIDENCE IN THE SHOWERS
OCCURRING IS STILL LOW, SO THEY WERE LEFT OUT FOR NOW. ALSO, WITH
THE POTENTIAL FOR SOME MIXING TO OCCUR, SO WE DID NOT HIT THE LOW
CONDITIONS HARD JUST YET...WE`LL SEE HOW LATER GUIDANCE HANDLES THE
OVERNIGHT PERIOD.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE DURING THE EARLY MORNING HOURS. ALSO, SCATTERED
SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON AND EVENING,
MAY REDUCE CEILINGS AND VISIBILITIES AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW ADVISORY LEVELS THROUGH
TODAY INTO TONIGHT. HOWEVER, WINDS COULD PERIODICALLY GUST AROUND 20
KNOTS, ESPECIALLY LATER TODAY INTO TONIGHT. ALSO, SEAS WILL REMAIN
NEAR 4 FEET THROUGH THE PERIOD, AND MAY GET CLOSE TO 5 FEET
OVERNIGHT. CONFIDENCE IN CONDITIONS GETTING CLOSE TO ADVISORY LEVELS
IS NOT HIGH ENOUGH TO ISSUE AN ADVISORY.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WEDNESDAY THROUGH
THURSDAY. AS THIS FLOW STRENGTHENS, WINDS AND SEAS WILL GRADUALLY
INCREASE. SEAS WILL START TO RISE TO NEAR 5 FEET BY WEDNESDAY
AFTERNOON WITH WINDS STARTING TO GUST IN ADVANCE OF AN APPROACHING
COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE WEDNESDAY
AND THURSDAY ON THE OCEAN FRONT.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SMALL CRAFT ADVISORY CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW
CRITERIA THROUGH THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS
THE REGION.
WITH SUCH A WARM, MOIST AIRMASS IN PLACE THROUGH THURSDAY, THERE
WILL REMAIN A CHANCE FOR SOME PATCHY DENSE FOG TO FORM OVER THE AREA
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...O`HARA
SHORT TERM...ROBERTSON
LONG TERM...MEOLA
AVIATION...ROBERTSON/MEOLA
MARINE...ROBERTSON/MEOLA
000
FXUS61 KPHI 211236
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
836 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED JUST OFF THE SOUTHEASTERN UNITED
STATES COAST THROUGH THURSDAY. LOW PRESSURE WILL APPROACH FROM THE
WEST, PASSING TO OUR NORTH, AND WILL DRAG A COLD FRONT THROUGH THE
REGION LATE THURSDAY INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD IN
FROM THE WEST FOR THE WEEKEND BEFORE MOVING OFFSHORE LATER SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE PUBLIC PRODUCTS HAVE BEEN UPDATED TO INCLUDE A SMALL CHC FOR
SHOWERS THIS MORNING ACROSS THE ERN SHORE OF MD/DEL/SRN NJ.
HIGH PRESSURE WILL REMAIN ACROSS THE SOUTHERN ATLANTIC TODAY, WHICH
WILL KEEP OUR AREA UNDER A RETURN FLOW. THIS WILL KEEP A FLOW OF
WARM, MOIST AIR ACROSS THE AREA. PATCHY LOW CLOUDS AND FOG EARLY
THIS MORNING WILL BURN OFF MY MID-MORNING, AND EVENTUALLY LEAD TO A
PARTLY TO MOSTLY CLOUDY DAY. A FRONTAL BOUNDARY WILL TRY TO SINK
TOWARD OUR AREA FROM THE NORTH TODAY, BUT IS NOT EXPECTED TO REACH
THIS FAR SOUTHWARD. MODEL GUIDANCE INDICATE A SHORT WAVE MOVING TO
OUR NORTH ALONG THIS BOUNDARY DURING THE DAY, AND ANOTHER SHORT WAVE
IS EXPECTED TO SKIRT JUST TO OUR SOUTH. ANY ORGANIZED PRECIPITATION
WOULD LIKELY BE FOCUSED NEAR THESE AREAS. HOWEVER, WITH A WARM AND
MOIST AIRMASS ACROSS THE AREA, THERE WILL BE SOME INSTABILITY
THROUGH THE DAY. THIS COULD LEAD TO SOME ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA, MAINLY LATE IN THE DAY.
MAV/MET MOS GUIDANCE GAVE SOME DIFFERENT NUMBERS FOR HIGHS TODAY
WITH THE MET SEVERAL DEGREES WARMER THAN THE MAV. TAKING A LOOK AT
925 MB TEMPERATURES, WE DECIDED TO TAKE A BLEND OF THE MOS NUMBERS,
WHICH WOULD GIVE MID-UPPER 80S FROM MUCH OF THE AREA, WITH LOW-MID
80S FOR OUR EASTERN AND SOUTHERN AREAS. AREAS RIGHT ALONG THE COAST
MAY NOT REACH 80 DEGREES HOWEVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SYNOPTIC SITUATION OVERNIGHT DOES NOT CHANGE MUCH FROM THE
DAYTIME. A STRONGER SHORT WAVE/VORT MAX ALOFT IS FORECAST TO
APPROACH THE AREA OVERNIGHT, AT THE SAME TIME A WEAK SURFACE TROUGH
MAY MOVE ACROSS THE AREA. THERE COULD STILL BE SOME INSTABILITY
OVERNIGHT, WHICH COULD LEAD TO THE CHANCE FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA. WE LEFT FOG OUT OF THE
FORECAST OVERNIGHT AS THERE MAY BE ENOUGH MIXING TO PREVENT MUCH OF
THE DENSER FOG FROM DEVELOPING. A BLEND OF THE MAV/MET MOS WAS TAKEN
FOR OVERNIGHT LOWS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE DOMINATES OUR WEATHER OVER THE NEXT SEVERAL DAYS AS IT
SETS UP SHOP OVER THE SOUTHWESTERN ATLANTIC. WITH THE HIGH TO OUR
SOUTHEAST, WE WILL SEE A SOUTHWESTERLY FLOW CONTINUE ACROSS THE
REGION. THIS SOUTHWEST FLOW WILL ADVECT WARM AND MOIST AIR TO OUR
AREA AND WE WILL REMAIN ABOVE NORMAL FOR TEMPERATURES THROUGH AT
LEAST MID WEEK. WITH ALL THAT MOIST, WARM AIR, WE WILL ALSO START TO
DESTABILIZE. THIS WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH THE WEEK, MAINLY IN THE AFTERNOON AFTER
SUFFICIENT DAYTIME HEATING HAS OCCURRED AND CONVECTIVE TEMPERATURES
HAVE BEEN REACHED.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST ON THURSDAY, WITH
THE CENTER PASSING OFF TO OUR NORTH. THE ATTACHED COLD FRONT IS
FORECAST TO MOVE THROUGH OUR AREA THURSDAY INTO FRIDAY, MOST LIKELY
LATER IN THE DAY THURSDAY INTO EARLY FRIDAY. THE LATEST MODEL
GUIDANCE HAS SLOWED DOWN THE FRONTAL PASSAGE AND WITH LITTLE SUPPORT
OVERALL, WE HAVE OPTED TO KEEP THE FORECAST LARGELY THE SAME AND
LEAN A BIT MORE ON THE PROGRESSIVE SIDE.
THE FRONT PUSHES THROUGH AND OFFSHORE BY FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT, BRINGING IN SOME COOLER AND
DRIER AIR FOR THE HOLIDAY WEEKEND. THE MODELS HINT AT A
SHORTWAVE MOVING THROUGH THE MID LEVELS LATE SATURDAY OR SUNDAY WITH
A LIGHT SHOWER POSSIBLE. THE AIR LOOKS LIKE IT MIGHT BE TOO DRY FOR
ANYTHING TO MAKE IT TO THE SURFACE AND WE HAVE KEPT THE HOLIDAY
WEEKEND POP FREE.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CIGS/VSBYS ARE NOW DEVELOPING ACROSS THE TAF SITES. THE LOW
CLOUDS/FOG WILL BURN OFF THROUGH THE MID MORNING HOURS, AND
CONDITIONS WILL EVENTUALLY BECOME VFR. THERE IS A CHANCE FOR SOME
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON, BUT
CONFIDENCE IN THEM HITTING A PARTICULAR TAF SITE IS LOW, SO THEY
WERE LEFT OUT OF THE FORECAST FOR THE TIME BEING.
ANOTHER ROUND OF LOW CLOUDS/FOG IS POSSIBLE AGAIN TUESDAY NIGHT.
HOWEVER, THERE IS ALSO THE POSSIBILITY FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS OVERNIGHT AS WELL. CONFIDENCE IN THE SHOWERS
OCCURRING IS STILL LOW, SO THEY WERE LEFT OUT FOR NOW. ALSO, WITH
THE POTENTIAL FOR SOME MIXING TO OCCUR, SO WE DID NOT HIT THE LOW
CONDITIONS HARD JUST YET...WE`LL SEE HOW LATER GUIDANCE HANDLES THE
OVERNIGHT PERIOD.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE DURING THE EARLY MORNING HOURS. ALSO, SCATTERED
SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON AND EVENING,
MAY REDUCE CEILINGS AND VISIBILITIES AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW ADVISORY LEVELS THROUGH
TODAY INTO TONIGHT. HOWEVER, WINDS COULD PERIODICALLY GUST AROUND 20
KNOTS, ESPECIALLY LATER TODAY INTO TONIGHT. ALSO, SEAS WILL REMAIN
NEAR 4 FEET THROUGH THE PERIOD, AND MAY GET CLOSE TO 5 FEET
OVERNIGHT. CONFIDENCE IN CONDITIONS GETTING CLOSE TO ADVISORY LEVELS
IS NOT HIGH ENOUGH TO ISSUE AN ADVISORY.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WEDNESDAY THROUGH
THURSDAY. AS THIS FLOW STRENGTHENS, WINDS AND SEAS WILL GRADUALLY
INCREASE. SEAS WILL START TO RISE TO NEAR 5 FEET BY WEDNESDAY
AFTERNOON WITH WINDS STARTING TO GUST IN ADVANCE OF AN APPROACHING
COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE WEDNESDAY
AND THURSDAY ON THE OCEAN FRONT.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SMALL CRAFT ADVISORY CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW
CRITERIA THROUGH THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS
THE REGION.
WITH SUCH A WARM, MOIST AIRMASS IN PLACE THROUGH THURSDAY, THERE
WILL REMAIN A CHANCE FOR SOME PATCHY DENSE FOG TO FORM OVER THE AREA
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...MEOLA
AVIATION...ROBERTSON/MEOLA
MARINE...ROBERTSON/MEOLA
000
FXUS61 KPHI 210810
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
410 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED JUST OFF THE SOUTHEASTERN UNITED
STATES COAST THROUGH THURSDAY. LOW PRESSURE WILL APPROACH FROM THE
WEST, PASSING TO OUR NORTH, AND WILL DRAG A COLD FRONT THROUGH THE
REGION LATE THURSDAY INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD IN
FROM THE WEST FOR THE WEEKEND BEFORE MOVING OFFSHORE LATER SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL REMAIN ACROSS THE SOUTHERN ATLANTIC TODAY, WHICH
WILL KEEP OUR AREA UNDER A RETURN FLOW. THIS WILL KEEP A FLOW OF
WARM, MOIST AIR ACROSS THE AREA. PATCHY LOW CLOUDS AND FOG EARLY
THIS MORNING WILL BURN OFF MY MID-MORNING, AND EVENTUALLY LEAD TO A
PARTLY TO MOSTLY CLOUDY DAY. A FRONTAL BOUNDARY WILL TRY TO SINK
TOWARD OUR AREA FROM THE NORTH TODAY, BUT IS NOT EXPECTED TO REACH
THIS FAR SOUTHWARD. MODEL GUIDANCE INDICATE A SHORT WAVE MOVING TO
OUR NORTH ALONG THIS BOUNDARY DURING THE DAY, AND ANOTHER SHORT WAVE
IS EXPECTED TO SKIRT JUST TO OUR SOUTH. ANY ORGANIZED PRECIPITATION
WOULD LIKELY BE FOCUSED NEAR THESE AREAS. HOWEVER, WITH A WARM AND
MOIST AIRMASS ACROSS THE AREA, THERE WILL BE SOME INSTABILITY
THROUGH THE DAY. THIS COULD LEAD TO SOME ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA, MAINLY LATE IN THE DAY.
MAV/MET MOS GUIDANCE GAVE SOME DIFFERENT NUMBERS FOR HIGHS TODAY
WITH THE MET SEVERAL DEGREES WARMER THAN THE MAV. TAKING A LOOK AT
925 MB TEMPERATURES, WE DECIDED TO TAKE A BLEND OF THE MOS NUMBERS,
WHICH WOULD GIVE MID-UPPER 80S FROM MUCH OF THE AREA, WITH LOW-MID
80S FOR OUR EASTERN AND SOUTHERN AREAS. AREAS RIGHT ALONG THE COAST
MAY NOT REACH 80 DEGREES HOWEVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SYNOPTIC SITUATION OVERNIGHT DOES NOT CHANGE MUCH FROM THE
DAYTIME. A STRONGER SHORT WAVE/VORT MAX ALOFT IS FORECAST TO
APPROACH THE AREA OVERNIGHT, AT THE SAME TIME A WEAK SURFACE TROUGH
MAY MOVE ACROSS THE AREA. THERE COULD STILL BE SOME INSTABILITY
OVERNIGHT, WHICH COULD LEAD TO THE CHANCE FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA. WE LEFT FOG OUT OF THE
FORECAST OVERNIGHT AS THERE MAY BE ENOUGH MIXING TO PREVENT MUCH OF
THE DENSER FOG FROM DEVELOPING. A BLEND OF THE MAV/MET MOS WAS TAKEN
FOR OVERNIGHT LOWS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE DOMINATES OUR WEATHER OVER THE NEXT SEVERAL DAYS AS IT
SETS UP SHOP OVER THE SOUTHWESTERN ATLANTIC. WITH THE HIGH TO OUR
SOUTHEAST, WE WILL SEE A SOUTHWESTERLY FLOW CONTINUE ACROSS THE
REGION. THIS SOUTHWEST FLOW WILL ADVECT WARM AND MOIST AIR TO OUR
AREA AND WE WILL REMAIN ABOVE NORMAL FOR TEMPERATURES THROUGH AT
LEAST MID WEEK. WITH ALL THAT MOIST, WARM AIR, WE WILL ALSO START TO
DESTABILIZE. THIS WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH THE WEEK, MAINLY IN THE AFTERNOON AFTER
SUFFICIENT DAYTIME HEATING HAS OCCURRED AND CONVECTIVE TEMPERATURES
HAVE BEEN REACHED.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST ON THURSDAY, WITH
THE CENTER PASSING OFF TO OUR NORTH. THE ATTACHED COLD FRONT IS
FORECAST TO MOVE THROUGH OUR AREA THURSDAY INTO FRIDAY, MOST LIKELY
LATER IN THE DAY THURSDAY INTO EARLY FRIDAY. THE LATEST MODEL
GUIDANCE HAS SLOWED DOWN THE FRONTAL PASSAGE AND WITH LITTLE SUPPORT
OVERALL, WE HAVE OPTED TO KEEP THE FORECAST LARGELY THE SAME AND
LEAN A BIT MORE ON THE PROGRESSIVE SIDE.
THE FRONT PUSHES THROUGH AND OFFSHORE BY FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT, BRINGING IN SOME COOLER AND
DRIER AIR FOR THE HOLIDAY WEEKEND. THE MODELS HINT AT A
SHORTWAVE MOVING THROUGH THE MID LEVELS LATE SATURDAY OR SUNDAY WITH
A LIGHT SHOWER POSSIBLE. THE AIR LOOKS LIKE IT MIGHT BE TOO DRY FOR
ANYTHING TO MAKE IT TO THE SURFACE AND WE HAVE KEPT THE HOLIDAY
WEEKEND POP FREE.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CIGS/VSBYS ARE NOW DEVELOPING ACROSS THE TAF SITES. THE LOW
CLOUDS/FOG WILL BURN OFF THROUGH THE MID MORNING HOURS, AND
CONDITIONS WILL EVENTUALLY BECOME VFR. THERE IS A CHANCE FOR SOME
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON, BUT
CONFIDENCE IN THEM HITTING A PARTICULAR TAF SITE IS LOW, SO THEY
WERE LEFT OUT OF THE FORECAST FOR THE TIME BEING.
ANOTHER ROUND OF LOW CLOUDS/FOG IS POSSIBLE AGAIN TUESDAY NIGHT.
HOWEVER, THERE IS ALSO THE POSSIBILITY FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS OVERNIGHT AS WELL. CONFIDENCE IN THE SHOWERS
OCCURRING IS STILL LOW, SO THEY WERE LEFT OUT FOR NOW. ALSO, WITH
THE POTENTIAL FOR SOME MIXING TO OCCUR, SO WE DID NOT HIT THE LOW
CONDITIONS HARD JUST YET...WE`LL SEE HOW LATER GUIDANCE HANDLES THE
OVERNIGHT PERIOD.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE DURING THE EARLY MORNING HOURS. ALSO, SCATTERED
SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON AND EVENING,
MAY REDUCE CEILINGS AND VISIBILITIES AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW ADVISORY LEVELS THROUGH
TODAY INTO TONIGHT. HOWEVER, WINDS COULD PERIODICALLY GUST AROUND 20
KNOTS, ESPECIALLY LATER TODAY INTO TONIGHT. ALSO, SEAS WILL REMAIN
NEAR 4 FEET THROUGH THE PERIOD, AND MAY GET CLOSE TO 5 FEET
OVERNIGHT. CONFIDENCE IN CONDITIONS GETTING CLOSE TO ADVISORY LEVELS
IS NOT HIGH ENOUGH TO ISSUE AN ADVISORY.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WEDNESDAY THROUGH
THURSDAY. AS THIS FLOW STRENGTHENS, WINDS AND SEAS WILL GRADUALLY
INCREASE. SEAS WILL START TO RISE TO NEAR 5 FEET BY WEDNESDAY
AFTERNOON WITH WINDS STARTING TO GUST IN ADVANCE OF AN APPROACHING
COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE WEDNESDAY
AND THURSDAY ON THE OCEAN FRONT.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SMALL CRAFT ADVISORY CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW
CRITERIA THROUGH THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS
THE REGION.
WITH SUCH A WARM, MOIST AIRMASS IN PLACE THROUGH THURSDAY, THERE
WILL REMAIN A CHANCE FOR SOME PATCHY DENSE FOG TO FORM OVER THE AREA
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...MEOLA
AVIATION...ROBERTSON/MEOLA
MARINE...ROBERTSON/MEOLA
000
FXUS61 KPHI 210121
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
921 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE 9-930 PM UPDATES: 630 PM FCST UPDATE ON TRACK. A QUIET NOW AND
WAITING TO SEE HOW EXTENSIVE THE FOG WILL BE.
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z NAM...THE
FCST SCENARIO TONIGHT AND TUESDAY IS BASED ON A BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. THE SECOND SMALL GROUP OF ISOLATED SHOWERS IN CUMBERLAND
COUNTY AROUND 8 PM HAS SINCE DISSIPATED.
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS. ITS SUMMERLIKE SITN SO NOT SURE HOW EXTENSIVE THE FOG BUT
WITH LIGHT WIND AND DECENT RADIATION CONDITIONS WE SHOULD SEE
AREAS OF DENSE FOG DEVELOP LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. AREAS OF LIFR FOG AND STRATUS SHOULD DEVELOP BETWEEN
05Z-09Z OVER THE COUNTRYSIDE TAF LOCATIONS AND MOVE CLOSE TO KPHL
BETWEEN 10Z-12Z. LIGHT S-SW WIND.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVES TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT THOSE SHOWERS WERE NOT INCLUDED
IN THE 18Z/20 TAFS. A LOW PROBABILITY OCCURRENCE. THAT CONVECTION
MAY NOT ARRIVE TIL AFTER DARK?
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOWERED THE SWELL A FOOT THROUGH TUESDAY BECAUSE OF A RECENT 1/2
TO 1 FT HIGH BIAS ON THE SWELL. INCREASED THE WNA4 PERIOD SLIGHTLY
TONIGHT SINCE IT WAS UNDERFCSTG BY 1-2 SECONDS.
OVERALL CAPPED SEAS AT 4 FT THROUGH 00Z WED.
THEREFORE NO HEADLINE ANTICIPATED THROUGH AT LEAST TUE AFTN.
THERE MAY BE AREAS OF FOG ON THE WATERS TONIGHT BUT DELAYED THE FOG
BECAUSE OF SW FLOW. CONFIDENCE FOR 2MI OR LESS FOG OVER THE WATER
IS BELOW AVG ON SW ISOBARIC FLOW. A SHOWERS OR TSTM IS POSSIBLE
TUE AFTERNOON BUT CONFIDENCE ON ANY QPF TUESDAY IS BELOW AVG.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 921
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG 921
MARINE...DRAG/NIERENBERG 921
CLIMATE...
000
FXUS61 KPHI 210021
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
821 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z NAM...THE
FCST SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. A NEW GROUP OF SCT SHOWERS HAS DEVELOPED OVER DE BAY AND
CUMBERLAND COUNTY 745-815PM EDT. WE JUST PROCESSED THIS AND UPDATED
THE GRIDS BUT DOES NOT READ ON THE LEGACY PRODUCTS DUE TO ITS
SHORT TERM EXISTENCE.
OTRW MODELS ARE NOW BASICALLY RAINFREE TONIGHT
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS.
SUMMERLIKE SITN SO NOT SURE HOW EXTENSIVE BUT WITH LIGHT WIND AND
DECENT RADIATION CONDITIONS WE SHOULD SEE AREAS OF DENSE FOG
DEVELOP LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR TO START. AREAS OF LIFR FOG AND STRATUS SHOULD DEVELOP
BETWEEN 05Z-09Z IN THE COUNTRYSIDE TAF LOCATIONS AND MOVE CLOSE TO
KPHL BETWEEN 10Z-12Z. LIGHT S-SW WIND.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS. THE CONVECTION MAY NOT ARRIVE TIL AFTER DARK?
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 820P
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...
000
FXUS61 KPHI 202343
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
743 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z NAM...THE
FCST SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. WE TRIED CODING IN THE ISOLATED SHOWERS IN OCEAN COUNTY
FOR 2 HRS BUT THE LEGACY AND POINT/CLICK PRODUCTS DID NOT PICK IT
UP.
OTRW THE 630 PM UPDATE COMPLETELY WITHDREW SHOWERS FROM THE FCST.
MODELS ARE NOW BASICALLY RAINFREE TONIGHT
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS.
SUMMERLIKE SITN SO NOT SURE HOW EXTENSIVE BUT WITH LIGHT WIND AND
DECENT RADIATION CONDITIONS WE SHOULD SEE AREAS OF DENSE FOG
DEVELOP LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR TO START. AREAS OF LIFR FOG AND STRATUS SHOULD DEVELOP
BETWEEN 05Z-09Z IN THE COUNTRYSIDE TAF LOCATIONS AND MOVE CLOSE TO
KPHL BETWEEN 10Z-12Z. LIGHT S-SW WIND.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS. THE CONVECTION MAY NOT ARRIVE TIL AFTER DARK?
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 743
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG 743
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...
000
FXUS61 KPHI 202238
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
638 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z
NAM...THE FCST SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF
THE ECMWF/NAM SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE
AS WELL AS THE NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. WE`VE SEEN THE ISOLATED SMALL SHOWERS IN OCEAN COUNTY AT
630 PM BUT THEY SHOULDNT LAST LONG AS THEY HEADS SEAWARD.
SO THE 630 PM UPDATE HAS COMPLETELY WITHDRAWN SHOWERS FROM THE
FCST. MODELS ARE NOW BASICALLY RAINFREE TONIGHT
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...GENERALLY VFR TO START. SOUTHWEST WIND AT 5 TO 10 KNOTS
FOR THE MOST PART EXCEPT SSE ALONG THE COASTS. VFR CONDITIONS WILL
LOWER AGAIN LATER TONIGHT IN FOG AND STRATUS AS THE HUMID AIRMASS
REMAIN IN PLACE WITH LIGHT WIND. WIDESPREAD IFR AND LIFR DEVELOPS
LATE.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 637P
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG 637P
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...
000
FXUS61 KPHI 202141
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
541 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF AND GFS AND 18Z NAM...THE FCST
SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING AND THE 630 PM UPDATE WILL COMPLETELY CUT OUT SHOWERS FROM THE
FCST UNLESS COSPA SAYS DIFFERENTLY. COSPA AT WORST PERMITS SPRINKLES
INTO SW DE BETWEEN 7P AND 730P.
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR EXTENSIVE FOG AGAIN LATE TONIGHT.
THE 458 PM LEGACY PRODUCT UPDATE REDUCED THE CHANCE OF SHOWERS THIS
EVENING AND WITHDRAW THUNDER. MOVEMENT OF ACTIVITY CROSSING CHES
BAY AT 5P IS SLOWLY ENE AND NOT ENOUGH INSTABILITY IS EXPECTED TO
REMAIN BY SUNDOWN FOR THUNDER IN OUR FCST AREA.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...GENERALLY VFR TO START. SOUTHWEST WIND AT 5 TO 10 KNOTS
FOR THE MOST PART EXCEPT SSE ALONG THE COASTS. VFR CONDITIONS WILL
LOWER AGAIN TONIGHT IN FOG AND STRATUS AS THE HUMID AIRMASS REMAIN
IN PLACE WITH LIGHT WIND. WIDESPREAD IFR AND LIFR DEVELOPS LATE.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG/O`HARA 540P
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/GAINES/NIERENBERG/O`HARA 540P
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...540P
000
FXUS61 KPHI 202104
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
504 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
458 PM LEGACY PRODUCT UPDATE REDUCING THE CHANCE OF SHOWERS THIS
EVENING AND WITHDRAW THUNDER. MOVEMENT OF ACTIVITY CROSSING CHES
BAY AT 5P IS SLOWLY ENE AND NOT ENOUGH INSTABILITY IS EXPECTED TO
REMAIN BY SUNDOWN FOR THUNDER IN OUR FCST AREA.
THE WARM FRONT IS NOW NORTH/EAST OF THE AREA AND OUR ENTIRE CWA
IS IN THE WARM SECTOR. SEVERAL HUMID DAYS ARE AHEAD WITH OVERNIGHT
PERIODS OF LOW CLOUDS/FOG AND THEN SLOW RECOVERY THE FOLLOWING
DAY.
TONIGHT...MOSTLY CLOUDY SKIES LATE THIS AFTERNOON WILL TRANSITION
TO PARTLY CLOUDY BY SUNSET. RADIATIONAL COOLING AND THE HUMID AIR
MASS WILL LEAD TO PLENTY OF FOG AGAIN TONIGHT. A FEW SCT SHOWERS
MAY OCCUR THIS EVENING ACROSS THE DELMARVA OR SRN NJ...BUT THE
CHCS ARE RATHER LOW. OVERNIGHT LOWS WILL BE IN THE LOW 60S NORTH
AND MID 60S ACROSS THE CENTRAL AND SRN AREAS. WINDS WILL BE LIGHT
MOSTLY FROM THE S OR SW.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...GENERALLY VFR TO START. SOUTHWEST WIND AT 5 TO 10 KNOTS
FOR THE MOST PART EXCEPT SSE ALONG THE COASTS.
CONDITIONS WILL LOWER AGAIN TONIGHT IN FOG AND SOME ST AS THE HUMID
AIRMASS REMAIN IN PLACE. IF HAVE FOLLOWED THE LAMP GUIDANCE FOR THE
MOST PART WITH WIDESPREAD IFR EXPECTED AGAIN. CONDITIONS WILL AGAIN
BE SLOW TO IMPROVE TUE MORNING...BUT EVENTUALLY VFR BY AFTERNOON.
SCT AFTERNOON SHOWERS/TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z MON
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG/O`HARA 504
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/GAINES/NIERENBERG/O`HARA 504
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
000
FXUS61 KPHI 201944
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
344 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE
THROUGH THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE
FOLLOWED BY A HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH
HOLIDAY THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE WARM FRONT IS NOW NORTH/EAST OF THE AREA AND OUR ENTIRE CWA IS
IN THE ARM SECTOR. SEVERAL HUMID DAYS ARE AHEAD WITH OVERNIGHT
PERIODS OF LOW CLOUDS/FOG AND THEN SLOW RECOVERY THE FOLLOWING DAY.
TONIGHT...MOSTLY CLOUDY SKIES LATE THIS AFTERNOON WILL TRANSITION TO
PARTLY CLOUDY BY SUNSET. RADIATIONAL COOLING AND THE HUMID AIR MASS
WILL LEAD TO PLENTY OF FOG AGAIN TONIGHT. A FEW SCT SHOWERS MAY
OCCUR THIS EVENING ACROSS THE DELMARVA OR SRN NJ...BUT THE CHCS ARE
RATHER LOW. OVERNIGHT LOWS WILL BE IN THE LOW 60S NORTH AND MID 60S
ACROSS THE CENTRAL AND SRN AREAS. WINDS WILL BE LIGHT MOSTLY FROM
THE S OR SW.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE LONG SLOW CLIMB BACK TO VFR HAS CONTINUED IN MOST AREAS...A FEW
HIGH-END MVFR STILL AT 18Z. DRIER AIR HAS ARRIVED ON A SWRLY/WRLY
FLOW ALOFT...SO CONDITIONS ARE A BIT BETTER TODAY WHEN COMPARED TO
SUNDAY. WINDS HAVE BEEN SOUTHWEST AT 5 TO 10 KNOTS FOR THE MOST
PART.
CONDITIONS WILL LOWER AGAIN TONIGHT IN FOG AND SOME ST AS THE HUMID
AIRMASS REMAIN IN PLACE. IF HAVE FOLLOWED THE LAMP GUIDANCE FOR THE
MOST PART WITH WIDESPREAD IFR EXPECTED AGAIN. CONDITIONS WILL AGAIN
BE SLOW TO IMPROVE TUE MORNING...BUT EVENTUALLY VFR BY AFTERNOON.
SCT AFTERNOON SHOWERS/TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z MON
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...GAINES/NIERENBERG/O`HARA
MARINE...GAINES/NIERENBERG/O`HARA
000
FXUS61 KPHI 201558
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1158 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-MORNING ESTF UPDATE HAS CONTINUED THE EARLIER TRENDS OF
SLOWLY DISSIPATING FOG AND SMALL BREAKS DEVELOPING IN THE LOW
CLOUDS. A FEW WIDELY SCATTERED SHOWERS CONTINUE ACROSS THE
DELMARVA REGION...THEY ARE MOVING NORTHEAST AT A GOOD CLIP. I HAVE
UPDATED SKY/WINDS/TEMPS WITH THIS FCST. MAX TEMPS WERE HELD ABOUT
THE SAME AS BEFORE. IT COULD BE A DIFFICULT MAX FCST IS BREAKS
BECOME MORE WIDESPREAD THAT CURRENTLY EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE WARM FRONT HAS PASSED NORTH/EAST OF THE AREA. SFC WINDS ACROSS
THE SRN HALF OF THE AREA FAVOR A SWRLY/WRLY DIRECTION WHILE WINDS
ARE CALM/VRB ELSEWHERE. THE FOG CONTINUES TO SLOWLY DISSIPATE
ACROSS THE AREA. I EXPECT A SLOW RETURN TO VFR IN MANY AREAS BY
AFTERNOON. ONCE THE SUN RETURNS...THE ATMOSPHERE WILL BECOME
UNSTABLE...WITH SCT SHOWERS AND PSBL TSTMS BY MID-AFTERNOON.
OVERALL CONFID IN LOCATION OF TSTM IS LOW AND THEY ARE NOT
INCLUDED IN ANY TAF ATTM.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
THE DENSE FOG ADVISORY ACROSS THE NORTHERN NJ COASTAL WATERS HAS
BEEN ALLOWED TO EXPIRE AT NOON. LOW END SCA CONDITIONS CONTINUE.
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON/O`HARA
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON/PO
MARINE...IOVINO/ROBERTSON/PO
000
FXUS61 KPHI 201335
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
935 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-MORNING ESTF UPDATE HAS CONTINUED THE EARLIER TRENDS OF
SLOWLY DISSIPATING FOG AND SMALL BREAKS DEVELOPING IN THE LOW
CLOUDS. A FEW WIDELY SCATTERED SHOWERS CONTINUE ACROSS THE
DELMARVA REGION...THEY ARE MOVING NORTHEAST AT A GOOD CLIP. I HAVE
UPDATED SKY/WINDS/TEMPS WITH THIS FCST. MAX TEMPS WERE HELD ABOUT
THE SAME AS BEFORE. IT COULD BE A DIFFICULT MAX FCST IS BREAKS
BECOME MORE WIDESPREAD THAT CURRENTLY EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE WARM FRONT HAS PASSED NORTH/EAST OF THE AREA. SFC WINDS ACROSS
THE SRN HALF OF THE AREA FAVOR A SWRLY/WRLY DIRECTION WHILE WINDS
ARE CALM/VRB ELSEWHERE. THE FOG CONTINUES TO SLOWLY DISSIPATE
ACROSS THE AREA. I EXPECT A SLOW RETURN TO VFR IN MANY AREAS BY
AFTERNOON. ONCE THE SUN RETURNS...THE ATMOSPHERE WILL BECOME
UNSTABLE...WITH SCT SHOWERS AND PSBL TSTMS BY MID-AFTERNOON.
OVERALL CONFID IN LOCATION OF TSTM IS LOW AND THEY ARE NOT
INCLUDED IN ANY TAF ATTM.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
THE DENSE FOG ADVISORY ON THE NRN TWO NJ COASTAL WATER ZONES HAS
BEEN EXTENDED UNTIL NOON.
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ450-451.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON/O`HARA
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON/PO
MARINE...IOVINO/ROBERTSON
000
FXUS61 KPHI 201206
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
806 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE DENSE FOG...IN MOST AREAS...HAS THINNED AND VSBYS HAVE
INCREASED ABOVE A MILE IN MANY AREAS. WE HAVE DECIDED TO CANCEL
THE DENSE FOG ADVISORY FOR NOW...WITH THE CAVEAT THAT THERE WILL
STILL BE A FEW AREAS OF THICKER FOG FOR THE NEXT FEW HOURS. SKIES
WILL GRADUALLY BECOME PARTLY SUNNY BY NOON. A FEW SHOWERS WILL
AFFECT SRN DEL IN A FEW HOURS WITH SMALL CHC POPS INSERTED IN THE
GRIDS/WORDS.
ONCE THE REMAINDER FOG LIFTS, CLOUDS MAY BEGIN TO BREAK SOME THIS
AFTERNOON, WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE SOME. A
WEAK DISTURBANCE ALOFT IS EXPECTED TO CROSS THE AREA LATER TODAY,
AND WITH AMPLE LOW-LEVEL MOISTURE AND INSTABILITY, SCATTERED
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TO DEVELOP.
WE HAVE NOT MADE ANY TEMPERATURE CHANGES TO THE FCST AT THIS
POINT, THE MET/MAV MOS NUMBERS FROM BEFORE STILL LOOK GOOD.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
IFR CONDITIONS PREVAIL ACROSS ALL TAF SITES EARLY THIS MORNING.
CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE THIS MORNING AS A
FRONTAL BOUNDARY SLOWLY LIFTS ACROSS THE AREA. SITES ARE EXPECTED
TO BECOME MVFR/VFR BY LATE MORNING/EARLY AFTERNOON. SCATTERED
SHOWERS AND A FEW ISOLATED THUNDERSTORMS ARE POSSIBLE TODAY,
ESPECIALLY THIS AFTERNOON. CONFIDENCE IN THUNDERSTORMS OCCURRING
IS LOW, SO THEY WERE NOT INCLUDED IN THE TAFS. WINDS THIS MORNING
WILL VARY FROM MORE OF AN EASTERLY DIRECTION NORTH OF THE FRONTAL
BOUNDARY, TO MORE SOUTHERLY SOUTH OF THE BOUNDARY. WINDS WILL
BECOME MORE SOUTH-SOUTHWESTERLY EVERYWHERE LATER THIS MORNING AND
THIS AFTERNOON.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
THE DENSE FOG ADVISORY ON THE NRN TWO NJ COASTAL WATER ZONES HAS
BEEN EXTENDED UNTIL NOON.
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ450-451.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...PO/ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON
MARINE...IOVINO/ROBERTSON
000
FXUS61 KPHI 200808
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
408 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE TO OUR EAST ACROSS THE ATLANTIC OCEAN WILL CONTINUE
TO SLIDE TO THE SOUTH AND EAST TODAY. A FRONTAL BOUNDARY WAS
DRAPED ACROSS SOUTHERN NEW JERSEY AND CENTRAL DELMARVA EARLY THIS
MORNING. THE FRONT IS EXPECTED TO SLOWLY MOVE NORTHWARD THIS
MORNING, AND MAY END UP WASHING OUT AS IT LIFTS THROUGH THE AREA.
AREAS OF DENSE FOG WILL REMAIN ACROSS THE AREA NORTH OF THE SLOW
MOVING FRONTAL BOUNDARY, SO THE DENSE FOG ADVISORY REMAINS THROUGH
8 AM. AS THIS BOUNDARY LIFTS ACROSS THE AREA, THE FOG WILL
DISSIPATE SOME BEHIND THE BOUNDARY. EVEN IF THE BOUNDARY HAPPENS
TO DISSIPATE ACROSS THE AREA, FOG SHOULD BEGIN TO DISSIPATE BY
LATE MORNING.
ONCE THE FOG LIFTS, CLOUDS MAY BEGIN TO BREAK SOME THIS
AFTERNOON, WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE SOME. A
WEAK DISTURBANCE ALOFT IS EXPECTED TO CROSS THE AREA LATER TODAY,
AND WITH AMPLE LOW-LEVEL MOISTURE AND INSTABILITY, SCATTERED
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TO DEVELOP.
MAV/MET MOS NUMBERS WERE SIMILAR, SO A BLEND OF THE GUIDANCE WAS
TAKEN FOR TEMPERATURES TODAY. WITH THE CLOUDS AND FOG THIS
MORNING, IT MAY TAKE A WHILE FOR TEMPERATURES TO START RISING.
HOWEVER, ONCE THE SUN BREAKS OUT, TEMPERATURES SHOULD INCREASE
FAIRLY STEADILY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
IFR CONDITIONS PREVAIL ACROSS ALL TAF SITES EARLY THIS MORNING.
CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE THIS MORNING AS A
FRONTAL BOUNDARY SLOWLY LIFTS ACROSS THE AREA. SITES ARE EXPECTED
TO BECOME MVFR/VFR BY LATE MORNING/EARLY AFTERNOON. SCATTERED
SHOWERS AND A FEW ISOLATED THUNDERSTORMS ARE POSSIBLE TODAY,
ESPECIALLY THIS AFTERNOON. CONFIDENCE IN THUNDERSTORMS OCCURRING
IS LOW, SO THEY WERE NOT INCLUDED IN THE TAFS. WINDS THIS MORNING
WILL VARY FROM MORE OF AN EASTERLY DIRECTION NORTH OF THE FRONTAL
BOUNDARY, TO MORE SOUTHERLY SOUTH OF THE BOUNDARY. WINDS WILL
BECOME MORE SOUTH-SOUTHWESTERLY EVERYWHERE LATER THIS MORNING AND
THIS AFTERNOON.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR PAZ054-055-
060>062-070-071-101>106.
NJ...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR NJZ001-
007>010-012>020-026-027.
DE...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR DEZ001.
MD...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MDZ008.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ450-451.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON
MARINE...IOVINO/ROBERTSON
000
FXUS61 KPHI 200625
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
225 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A QUICK UPDATE TO ISSUE A DENSE FOG ADVISORY FOR A GOOD PORTION OF
THE AREA. THE FRONTAL BOUNDARY IS DRAPED ACROSS THE CENTRAL
DELMARVA AND SOUTHERN NEW JERSEY EARLY THIS MORNING. AREAS NORTH
OF THE BOUNDARY HAVE DEVELOPED DENSE FOG WITH WIDESPREAD 1/4-1/2
MILE VISIBILITIES REPORTED. WE WILL RUN IT THROUGH 8 AM AND SEE
HOW THE VISIBILITIES DO OVER THE NEXT FEW HOURS AS THE FRONT TRIES
TO SLOWLY MOVE NORTHWARD.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH FOG WILL
PRECEDE THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS
OVERALL WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT
CHC/LOW CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS
EVENING AND THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE
TOO LOW TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER
50S ACROSS THE NORTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS TONIGHT INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW WILL
REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE AREA.
ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S THEN
SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN EVENTUAL
SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE SHOWS THE
TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
A QUICK UPDATE TO THE FORECAST TO ISSUE A DENSE FOG ADVISORY.
DENSE FOG IS PRETTY WIDESPREAD ON THE LAND, AND WITH DEWPOINTS
NEAR OR HIGHER THAN THE WATER TEMPERATURES, DENSE FOG IS LIKELY
OCCURRING ACROSS A PORTION OF OUR COASTAL WATERS.
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS
AND OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE
SOUTHERN WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE
ONGOING FLAG WILL CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE
SUGGESTS THAT THE CONDITIONS WILL CONTINUE INTO MONDAY...SO WE
WILL EXTEND THE FLAG FOR NOW...ALTHOUGH IT WILL BE A LOW-END
ADVISORY AT BEST. OCNL SHOWERS AND FOG ON THE WATERS TONIGHT AND
SCAT SHOWERS OR A TSTM MONDAY. WINDS WILL VEER TO SRLY LATE
TONIGHT AND THEN BECOME SWRLY ON MONDAY AS THE WARM FRONT CROSSES
THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.EQUIPMENT...
NWR LEWES DE HAS RETURNED TO SERVICE..
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR PAZ054-055-
060>062-070-071-101>106.
NJ...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR NJZ001-
007>010-012>020-026-027.
DE...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR DEZ001.
MD...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MDZ008.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ450-451.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/ROBERTSON/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/ROBERTSON/O`HARA
EQUIPMENT...
000
FXUS61 KPHI 200151
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
951 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATE THIS EVENING, PATCHY FOG AND DRIZZLE WERE OBSERVED ACROSS
PORTIONS OF THE FORECAST AREA, ESPECIALLY INTO CENTRAL AND
SOUTHERN PARTS OF NJ AND INTO THE HIGHER TERRAIN OF THE POCONOS.
FARTHER SOUTH, ISOLATED SHOWERS WERE ONGOING INTO CENTRAL PORTIONS
OF OUR DELMARVA AREA, JUST NORTH OF A FRONTAL BOUNDARY. WE
ANTICIPATE THESE TRENDS TO CONTINUE THROUGH THE OVERNIGHT WITH THE
OVERALL ONSHORE FLOW CONTINUING, WITH VERY MOIST AIR PRESENT IN
THE LOW LEVELS. TEMPERATURES THROUGH THE OVERNIGHT WILL LIKELY
REMAIN FAIRLY STEADY OR ONLY DROP ANOTHER COUPLE OF DEGREES.
MINIMUM TEMPERATURES LOOK ON TRACK, AND A FEW TWEAKS WERE MADE TO
HOURLY TEMPS AND DEWPOINTS GOING INTO THE OVERNIGHT HOURS.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL CONTINUE TONIGHT...THE FRONT WILL CROSS THROUGH
OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH SOME FOG WILL PRECEDE
THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS OVERALL
WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT CHC/LOW
CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS EVENING AND
THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE TOO LOW
TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER 50S ACROSS
THE NORTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS TONIGHT INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW WILL
REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE AREA.
ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S THEN
SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN EVENTUAL
SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE SHOWS THE
TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS AND
OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE SOUTHERN
WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE ONGOING FLAG WILL
CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE SUGGESTS THAT THE
CONDITIONS WILL CONTINUE INTO MONDAY...SO WE WILL EXTEND THE FLAG
FOR NOW...ALTHOUGH IT WILL BE A LOW-END ADVISORY AT BEST. OCNL
SHOWERS AND SOME FOG ON THE WATERS TONIGHT AND SCAT SHOWERS OR A
TSTM MONDAY. WINDS WILL VEER TO SRLY LATE TONIGHT AND THEN BECOME
SWRLY ON MONDAY AS THE WARM FRONT CROSSES THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.EQUIPMENT...
NWR LEWES DE HAS RETURNED TO SERVICE..
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
EQUIPMENT...822
000
FXUS61 KPHI 200023
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
823 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WITH THE EARLY EVENING UPDATE, SOME BREAKS IN THE CLOUDS THROUGH
OUR SOUTHERN DELMARVA ZONES HAVE ALLOWED ADDITIONAL SFC WARMING TO
OCCUR, AND A QUICK RISE IN LATE-DAY TEMPERATURES RESULTED. WE ADJUSTED
HOURLY TEMPS ACCORDINGLY FOR THE NEXT FEW HOURS USING LAV/LAMP
GUIDANCE WHICH CAPTURED THIS TREND FAIRLY WELL. IN ADDITION, THIS
LATE-DAY HEATING HAS ALLOWED SOME ISOLATED INSTABILITY SHOWERS TO
DEVELOP JUST NORTH OF A WARM FRONT INTO OUR SOUTHERN DELMARVA
AREA, AND WE INCREASED POPS AND QPF SOME TO REFLECT THESE TRENDS.
SOME LOCATIONS, ESPECIALLY INTO SUSSEX DE, MAY EXPERIENCE A BRIEF
HEAVY SHOWER THROUGH EARLY THIS EVENING. ELSEWHERE, HIGH CHANCE TO
LIKELY POPS WERE CONTINUED FOR THE NEXT FEW HOURS ACROSS CENTRAL
PORTIONS OF NJ AND THE ADJACENT COASTAL WATERS WHERE DRIZZLE AND
SOME STEADIER LIGHT SHOWERS ARE ONGOING.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL CONTINUE TONIGHT...THE FRONT WILL CROSS THROUGH
OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH SOME FOG WILL PRECEDE
THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS OVERALL
WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT CHC/LOW
CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS EVENING AND
THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE TOO LOW
TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER 50S ACROSS
THE NORTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS THIS EVENING INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW
WILL REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE
AREA. ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S
THEN SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN
EVENTUAL SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE
SHOWS THE TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS AND
OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE SOUTHERN
WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE ONGOING FLAG WILL
CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE SUGGESTS THAT THE
CONDITIONS WILL CONTINUE INTO MONDAY...SO WE WILL EXTEND THE FLAG
FOR NOW...ALTHOUGH IT WILL BE A LOW-END ADVISORY AT BEST. OCNL
SHOWERS AND SOME FOG ON THE WATERS TONIGHT AND SCAT SHOWERS OR A
TSTM MONDAY. WINDS WILL VEER TO SRLY LATE TONIGHT AND THEN BECOME
SWRLY ON MONDAY AS THE WARM FRONT CROSSES THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.EQUIPMENT...
NWR LEWES DE HAS RETURNED TO SERVICE..
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
EQUIPMENT...822
000
FXUS61 KPHI 192340
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
740 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WITH THE EARLY EVENING UPDATE, SOME BREAKS IN THE CLOUDS THROUGH
OUR SOUTHERN DELMARVA ZONES HAVE ALLOWED ADDITIONAL SFC WARMING TO
OCCUR, AND A QUICK RISE IN LATE-DAY TEMPERATURES RESULTED. WE ADJUSTED
HOURLY TEMPS ACCORDINGLY FOR THE NEXT FEW HOURS USING LAV/LAMP
GUIDANCE WHICH CAPTURED THIS TREND FAIRLY WELL. IN ADDITION, THIS
LATE-DAY HEATING HAS ALLOWED SOME ISOLATED INSTABILITY SHOWERS TO
DEVELOP JUST NORTH OF A WARM FRONT INTO OUR SOUTHERN DELMARVA
AREA, AND WE INCREASED POPS AND QPF SOME TO REFLECT THESE TRENDS.
SOME LOCATIONS, ESPECIALLY INTO SUSSEX DE, MAY EXPERIENCE A BRIEF
HEAVY SHOWER THROUGH EARLY THIS EVENING. ELSEWHERE, HIGH CHANCE TO
LIKELY POPS WERE CONTINUED FOR THE NEXT FEW HOURS ACROSS CENTRAL
PORTIONS OF NJ AND THE ADJACENT COASTAL WATERS WHERE DRIZZLE AND
SOME STEADIER LIGHT SHOWERS ARE ONGOING.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL CONTINUE TONIGHT...THE FRONT WILL CROSS THROUGH
OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH SOME FOG WILL PRECEDE
THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS OVERALL
WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT CHC/LOW
CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS EVENING AND
THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE TOO LOW
TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER 50S ACROSS
THE NORTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS THIS EVENING INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW
WILL REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE
AREA. ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S
THEN SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN
EVENTUAL SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE
SHOWS THE TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS AND
OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE SOUTHERN
WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE ONGOING FLAG WILL
CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE SUGGESTS THAT THE
CONDITIONS WILL CONTINUE INTO MONDAY...SO WE WILL EXTEND THE FLAG
FOR NOW...ALTHOUGH IT WILL BE A LOW-END ADVISORY AT BEST. OCNL
SHOWERS AND SOME FOG ON THE WATERS TONIGHT AND SCAT SHOWERS OR A
TSTM MONDAY. WINDS WILL VEER TO SRLY LATE TONIGHT AND THEN BECOME
SWRLY ON MONDAY AS THE WARM FRONT CROSSES THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.EQUIPMENT...
NWR LEWES DE HAS BEEN OFF THE AIR SINCE ABOUT 7 PM THIS SUNDAY
EVENING MAY 19. TECHNICIANS HAVE BEEN INFORMED. WE DO NOT KNOW WHEN
IT WILL RETURN TO SERVICE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
EQUIPMENT...DRAG 741
000
FXUS61 KPHI 192202
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
602 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WITH THE EARLY EVENING UPDATE, SOME BREAKS IN THE CLOUDS THROUGH
OUR SOUTHERN DELMARVA ZONES HAVE ALLOWED ADDITIONAL SFC WARMING TO
OCCUR, AND A QUICK RISE IN LATE-DAY TEMPERATURES RESULTED. WE ADJUSTED
HOURLY TEMPS ACCORDINGLY FOR THE NEXT FEW HOURS USING LAV/LAMP
GUIDANCE WHICH CAPTURED THIS TREND FAIRLY WELL. IN ADDITION, THIS
LATE-DAY HEATING HAS ALLOWED SOME ISOLATED INSTABILITY SHOWERS TO
DEVELOP JUST NORTH OF A WARM FRONT INTO OUR SOUTHERN DELMARVA
AREA, AND WE INCREASED POPS AND QPF SOME TO REFLECT THESE TRENDS.
SOME LOCATIONS, ESPECIALLY INTO SUSSEX DE, MAY EXPERIENCE A BRIEF
HEAVY SHOWER THROUGH EARLY THIS EVENING. ELSEWHERE, HIGH CHANCE TO
LIKELY POPS WERE CONTINUED FOR THE NEXT FEW HOURS ACROSS CENTRAL
PORTIONS OF NJ AND THE ADJACENT COASTAL WATERS WHERE DRIZZLE AND
SOME STEADIER LIGHT SHOWERS ARE ONGOING.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL CONTINUE TONIGHT...THE FRONT WILL CROSS THROUGH
OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH SOME FOG WILL PRECEDE
THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS OVERALL
WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT CHC/LOW
CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS EVENING AND
THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE TOO LOW
TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER 50S ACROSS
THE NORTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS THIS EVENING INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW
WILL REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE
AREA. ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S
THEN SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN
EVENTUAL SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE
SHOWS THE TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS AND
OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE SOUTHERN
WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE ONGOING FLAG WILL
CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE SUGGESTS THAT THE
CONDITIONS WILL CONTINUE INTO MONDAY...SO WE WILL EXTEND THE FLAG
FOR NOW...ALTHOUGH IT WILL BE A LOW-END ADVISORY AT BEST. OCNL
SHOWERS AND SOME FOG ON THE WATERS TONIGHT AND SCAT SHOWERS OR A
TSTM MONDAY. WINDS WILL VEER TO SRLY LATE TONIGHT AND THEN BECOME
SWRLY ON MONDAY AS THE WARM FRONT CROSSES THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
000
FXUS61 KPHI 192006
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
406 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM FRONT WILL
CONTINUE TONIGHT...THE FRONT WILL CROSS THROUGH OVERNIGHT. LOW
CLOUDS AND DRIZZLE ALONG WITH SOME FOG WILL PRECEDE THE FRONT AND A
FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS OVERALL WILL SLOWLY
DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT CHC/LOW CHC BY
MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS EVENING AND THEN VEER
TO SWRLY BY MON MORNING. LOWS WILL NOT TOO LOW TONIGHT...WITH LOWS
60S ACROSS THE SRN AREAS AND UPPER 50S ACROSS THE NORTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS THIS EVENING INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW
WILL REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE
AREA. ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S
THEN SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN
EVENTUAL SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE
SHOWS THE TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS AND
OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE SOUTHERN
WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE ONGOING FLAG WILL
CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE SUGGESTS THAT THE
CONDITIONS WILL CONTINUE INTO MONDAY...SO WE WILL EXTEND THE FLAG
FOR NOW...ALTHOUGH IT WILL BE A LOW-END ADVISORY AT BEST. OCNL
SHOWERS AND SOME FOG ON THE WATERS TONIGHT AND SCAT SHOWERS OR A
TSTM MONDAY. WINDS WILL VEER TO SRLY LATE TONIGHT AND THEN BECOME
SWRLY ON MONDAY AS THE WARM FRONT CROSSES THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...O`HARA/DELISI
MARINE...O`HARA/DELISI
000
FXUS61 KPHI 191628
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1228 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND
DISSIPATE AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. MEANWHILE,
HIGH PRESSURE SHOULD REMAIN TO OUR NORTHEAST AND EAST. ANOTHER
FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO OUR
REGION LATE ON TUESDAY AND IT SHOULD LIFT BACK TO THE NORTH ON
WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS THEN EXPECTED
TO ARRIVE ON FRIDAY, FOLLOWED BY HIGH PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE ONSHORE LOW LEVEL FLOW WILL CONTINUE THIS AFTERNOON WITH A
WEALTH OF LOW LEVEL CLOUDINESS EXPECTED. AN AREA OF SHOWERS
PRESENTLY OVER ERN NJ WILL CONTINUE THROUGH EARLY AFTERNOON
BEFORE MOVING OFF TO THE EAST. SOME SHOWERS ARE EXPECTED TO
DEVELOP ACROSS THE SRN AREAS AND MOVE OVER THE AREA LATER TODAY.
THE LATEST HRRR AND NAM RUNS HOWEVER HAVE LIMITED COVERAGE OF
THESE SHOWERS AND HAVE REDUCED POPS TO HIGH CHANCE. IF A FEW
BREAKS IN THE CLOUDS DEVELOP ACROSS THE DELMARVA...A FEW POP-UP
TSTMS MAY OCCUR. THE POSSIBILITY OF THIS LOOKS LOW ENOUGH ATTM TO
KEEP OUT OF THE FCST.
TEMPERATURES WILL REMAIN IN CHECK...WITH THE ABUNDANCE OF CLOUDS.
READINGS IN THE MID/UPPER 60S ACROSS THE NRN AREAS AND UPPER 60S
TO LOW 70S OVER THE SRN AREAS. WINDS WILL BE EAST/SOUTHEAST AT 5
TO 10 MPH MUCH OF THE AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE AFOREMENTIONED MID LEVEL FEATURE LOOKS TO LINGER NEAR THE MID
ATLANTIC TONIGHT, AS A RIDGE ALOFT GRADUALLY SLIDES EASTWARD. HIGH
PRESSURE AT THE SURFACE AS A RESULT IS FORECAST TO SLIDE FARTHER
TO OUR EAST, WHICH WILL ALLOW THE LOW-LEVEL FLOW TO VEER FROM
SOUTHEAST TO MORE SOUTH OR SOUTHWEST OVERNIGHT. THIS MAINTAINS
THETA-E ADVECTION THROUGH THE NIGHT WITH AT LEAST SOME WAA AS
WELL. THERE DOES NOT APPEAR TO BE MUCH IN THE WAY OF ORGANIZED
LIFT MOVING THROUGH, THEREFORE THE SHOWERS DURING THE DAY SHOULD
DECREASE IN AREAL COVERAGE.
HOWEVER, AS THE FLOW VEERS AND MOISTURE INCREASES IN THE LOWER
LEVELS SOME MODEL GUIDANCE INDICATES THAT THIS MOISTURE GENERALLY
BECOMES LOCKED IN THE LOWEST LEVELS. IF ENOUGH DRYING CAN OCCUR
ABOVE THIS, THEN SOME DRIZZLE MAY BE THE MAIN PRECIPITATION TYPE
DURING THE COURSE OF THE NIGHT. THIS COULD BE MAINLY FOR OUR
CENTRAL AND NORTHERN ZONES, AS FARTHER SOUTH ENOUGH WARMING MAY
RESULT IN THE CLOUD BASES RISING SOME AND A LESS CONDUCIVE SETUP
FOR DRIZZLE. WE NOTICED THAT SOME OF THE HIGH RESOLUTION GUIDANCE
INDICATES LITTLE TO NO PRECIPITATION OCCURRING DURING THE NIGHT,
WITH PERHAPS SOME SHOWERS DEVELOPING TOWARD DAYBREAK AS SOME
PVA/LIFT ARRIVES FROM THE SOUTHWEST WITH THE MID LEVEL FEATURE. AS
A RESULT, WE LOWERED POPS INTO THE CHC RANGE AND CARRIED SHOWERS
FAR SOUTH WITH LIGHT RAIN/DRIZZLE FARTHER NORTH. WE ALSO ADDED IN
PATCHY FOG, FIRST STARTING IN THE HIGHER TERRAIN THEN TO OTHER
AREAS.
AS FOR LOW TEMPERATURES, WE MAINLY USED AN EVEN GFS/NAM MOS
BLEND. TEMPERATURES SHOULD BE ON THE MILD SIDE GIVEN THE CLOUDS
AND CONTINUED WAA. THERE IS A CHC THAT ESPECIALLY THE FAR SOUTHERN
AREAS HAVE SOME INCREASE IN THE TEMPERATURES OVERNIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX WELL
TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI RIVER
VALLEY ON MONDAY. THERE SHOULD BE A RIDGE EXTENDING FROM THE
SOUTHEASTERN STATES TO THE GREAT LAKES. THE POLAR VORTEX WILL
REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA DURING THE NEW
WEEK. MEANWHILE, THE CLOSED LOW TO OUR WEST AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD, GRADUALLY SQUEEZING THE RIDGE AND
PUSHING IT OUT OVER THE ATLANTIC. AS THE TROUGH BEGINS TO MOVE
TOWARD THE EASTERN STATES, IT SHOULD START TO INTERACT WITH THE
POLAR VORTEX AROUND WEDNESDAY AS THAT FEATURE`S INFLUENCE BEGINS
TO EXPAND TO THE WEST AND SOUTH. THE RESULTING MID LEVEL TROUGH
WILL LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES AND THE
NORTHEASTERN STATES IN THE THURSDAY THROUGH SATURDAY TIME FRAME.
THE SURFACE FLOW IS FORECAST TO VEER TO THE SOUTH AND SOUTHWEST
FOR MONDAY AND MONDAY NIGHT CAUSING THE CLOUDS TO LIFT AND
TEMPERATURES TO WARM, RESULTING IN THE DEVELOPMENT OF UNSTABLE
CONDITIONS, ESPECIALLY AWAY FROM THE OCEAN. SURFACE BASED CAPE
VALUES ARE ANTICIPATED TO RISE NEAR 1000 J/KG IN OUR WESTERN
COUNTIES DURING THE AFTERNOON. A FAIR AMOUNT OF LOW LEVEL MOISTURE
WILL REMAIN IN OUR REGION. AS A RESULT, WE WILL CONTINUE TO
MENTION A CHANCE OF SHOWERS FOR MONDAY AND WE WILL ALSO INCLUDE
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS. THE GUIDANCE IS
INDICATING A DECREASE IN PRECIPITATION FOR MONDAY NIGHT WITH THE
LOSS OF DAYTIME HEATING AND WITH THE LACK OF ANY FOCUSING
MECHANISM.
TEMPERATURES ARE FORECAST TO RISE NEAR +15C AT 850 HPA FOR
TUESDAY. A SOUTH TO SOUTHWEST SURFACE FLOW WILL CONTINUE AND
TEMPERATURES ARE EXPECTED TO RISE INTO THE LOWER AND MIDDLE 80S IN
MUCH OF OUR FORECAST AREA. LINGERING LOW LEVEL MOISTURE WILL HELP
ENHANCE THE INSTABILITY AND WE ARE ANTICIPATING SCATTERED SHOWERS
AND THUNDERSTORMS, ESPECIALLY IN THE AFTERNOON AND EVENING.
SURFACE BASED CAPE VALUES IN THE 1500 J/KG NEIGHBORHOOD ARE
POSSIBLE IN OUR SOUTHWESTERN COUNTIES. THE MOST UNSTABLE AREAS
WILL LIKELY HAVE PRECIPITABLE WATER VALUES IN EXCESS OF 1.5 INCHES
WITH THERE BEING THE POTENTIAL FOR LOCALIZED DOWNPOURS.
A FRONTAL BOUNDARY IS FORECAST TO DROP INTO OUR REGION FROM THE
NORTH LATE ON TUESDAY. THERE IS A FAIR AMOUNT OF UNCERTAINTY AS TO
HOW FAR SOUTH THE BOUNDARY WILL PROGRESS. IT SHOULD CONTINUE TO
HAVE A LEAST A LITTLE MOMENTUM INTO WEDNESDAY. HOWEVER, AS THE MID
LEVEL RIDGE AXIS PASSES OVERHEAD ON WEDNESDAY OR WEDNESDAY NIGHT,
THE BOUNDARY IS EXPECTED TO BEGIN LIFTING BACK TO THE NORTH.
REGARDLESS, UNSETTLED CONDITIONS WILL LIKELY CONTINUE.
AS THE MID LEVEL TROUGH BEGINS TO INFLUENCE OUR REGION LATE IN
THE WEEK IT SHOULD MOVE A COLD FRONT ACROSS THE NORTHEASTERN
STATES ON FRIDAY. AS A RESULT, WE WILL CARRY A CHANCE OF SHOWERS
AND AFTERNOON THUNDERSTORMS FOR FRIDAY.
WHILE THERE WILL BE A CHANCE OF PRECIPITATION IN THE FORECAST FOR
EACH DAY FROM MONDAY THROUGH FRIDAY, THE WEEK SHOULD NOT BE A
TOTAL WASHOUT. ACTUALLY, MOST OF THE TIME PRECIPITATION WILL NOT
BE FALLING. OVERALL, TEMPERATURES FOR THE WEEK SHOULD AVERAGE
ABOVE NORMAL FOR THIS TIME OF THE YEAR.
AFTER THE COLD FRONT PASSES, DRY AIR IS ANTICIPATED TO BEGIN
BUILDING INTO OUR REGION FROM THE NORTHWEST AND NORTH FOR FRIDAY
NIGHT AND SATURDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...MVFR/IFR CEILINGS PREVAIL THROUGH THE DAY, AND THERE IS
LOWER CONFIDENCE REGARDING ANY IMPROVEMENTS. IT IS POSSIBLE THAT
TERMINALS WITH IFR CEILINGS IMPROVE TO MVFR IN THE AFTERNOON, AND
THE VISIBILITIES SHOULD BE MOSTLY DEPENDENT ON THE SHOWERS.
SOUTHEAST WINDS GENERALLY NEAR 10 KNOTS.
TONIGHT...IFR CEILINGS, WITH A CHANCE FOR IMPROVEMENT TO MVFR
AT TIMES MAINLY SOUTH AND EAST OF KILG. OVERALL, SOME SHOWERS
SHOULD BE AROUND ESPECIALLY IN THE EVENING WITH EVEN THIS PERHAPS
TRANSITIONING TO SOME DRIZZLE, THEREFORE TIMES OF LOCAL VISIBILITY
RESTRICTIONS SHOULD OCCUR. SOME FOG IS ANTICIPATED WHICH WILL ALSO
LOWER THE LOCAL VISIBILITY, ALTHOUGH WE ARE CURRENTLY NOT
ANTICIPATING FOG TO REDUCE THE VISIBILITY TO UNDER 1SM. SOUTHEAST
WINDS 4-8 KNOTS, SHOULD TURN MORE SOUTH-SOUTHWEST.
OUTLOOK...
MONDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGH THE PERIOD WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
&&
.MARINE...
HIGH PRESSURE REMAINING TO OUR NORTHEAST TODAY WILL MAINTAIN A
SOUTHEASTERLY FLOW, ALTHOUGH THIS SHOULD START TO TURN MORE FROM
THE SOUTH LATER TODAY ACROSS THE SOUTHERN WATERS. THIS SHIFT TO
SOUTHERLY SHOULD THEN OVERSPREAD ALL THE WATERS TONIGHT. THIS FLOW
REGIME, WHICH IS ANTICIPATED TO REMAIN UNDER 25 KNOTS, WILL ALLOW
THE SEAS TO BUILD SOME MORE THOUGH. THE WAVEWATCH GUIDANCE HAS
BEEN RUNNING 1-2 FEET TO HIGH, HOWEVER IT IS CATCHING UP AS SEAS
REACHED 5 FEET EARLIER AT BUOY 44009. THESE HIGHER SEAS ARE
ANTICIPATED TO SPREAD NORTHWARD TODAY, HOWEVER CONFIDENCE IS NOT
ALL THAT HIGH THEY GET ABOVE 6 FEET. THEREFORE, THE SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR OUR OCEAN ZONES THROUGH TONIGHT.
THE CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA
ON DELAWARE BAY. SOME ADDITIONAL INCREASE IN THE DEW POINTS
TONIGHT COULD RESULT IN SOME FOG DEVELOPMENT.
OUTLOOK...
HIGH PRESSURE TO OUR NORTHEAST AND EAST WILL CONTINUE TO
INFLUENCE THE COASTAL WATERS OF NEW JERSEY AND DELAWARE INTO
TUESDAY. A FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP
INTO OUR REGION ON TUESDAY NIGHT BEFORE RETREATING BACK TO THE
NORTH ON WEDNESDAY AND THURSDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM MONDAY
THROUGH THURSDAY. WAVE HEIGHTS ON OUR OCEAN WATERS COULD REMAIN
AROUND 5 FEET ON MONDAY INTO MONDAY NIGHT AND THE CURRENT SMALL
CRAFT ADVISORY MAY NEED TO BE EXTENDED TO COVER THAT PERIOD. A
LULL IN WAVE HEIGHTS IS POSSIBLE FOR TUESDAY AND WEDNESDAY WITH 5
FOOT SEAS FORECAST TO RETURN TO OUR OCEAN WATERS FOR THURSDAY AS A
LONG SOUTHERLY FETCH BECOMES ESTABLISHED ALONG THE EAST COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GAINES/GORSE/O`HARA
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
000
FXUS61 KPHI 191341
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
941 AM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND
DISSIPATE AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. MEANWHILE,
HIGH PRESSURE SHOULD REMAIN TO OUR NORTHEAST AND EAST. ANOTHER
FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO OUR
REGION LATE ON TUESDAY AND IT SHOULD LIFT BACK TO THE NORTH ON
WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS THEN EXPECTED
TO ARRIVE ON FRIDAY, FOLLOWED BY HIGH PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE ONSHORE LOW LEVEL FLOW WILL CONTINUE THIS AFTERNOON WITH A
WEALTH OF LOW LEVEL CLOUDINESS EXPECTED. AN AREA OF SHOWERS
PRESENTLY OVER ERN NJ WILL CONTINUE THERE INTO THE EARLY AFTERNOON
BEFORE MOVING OFF TO THE EAST. OTHER SHOWERS ARE EXPECTED TO
DEVELOP ACROSS THE SRN AREAS AND MOVE OVER THE AREA THIS
AFTERNOON. WE HAVE CHOSEN TO MOSTLY KEEP THE EARLIER WORDING OF
SHOWERS LIKELY OVER MOST AREAS...WITH ONLY CHC POPS NORTH/WEST. IF
A FEW BREAKS IN THE CLOUDS DEVELOP ACROSS THE DELMARVA...A FEW
POP-UP TSTMS MAY OCCUR. THE POSSIBILITY OF THIS LOOKS LOW ENOUGH
ATTM TO KEEP OUT OF THE FCST.
TEMPERATURES WILL REMAIN IN CHECK...WITH THE ABUNDANCE OF CLOUDS.
READINGS IN THE MID/UPPER 60S ACROSS THE NRN AREAS AND UPPER 60S
TO LOW 70S OVER THE SRN AREAS. WINDS WILL BE EAST/SOUTHEAST AT 5
TO 10 MPH MUCH OF THE AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE AFOREMENTIONED MID LEVEL FEATURE LOOKS TO LINGER NEAR THE MID
ATLANTIC TONIGHT, AS A RIDGE ALOFT GRADUALLY SLIDES EASTWARD. HIGH
PRESSURE AT THE SURFACE AS A RESULT IS FORECAST TO SLIDE FARTHER
TO OUR EAST, WHICH WILL ALLOW THE LOW-LEVEL FLOW TO VEER FROM
SOUTHEAST TO MORE SOUTH OR SOUTHWEST OVERNIGHT. THIS MAINTAINS
THETA-E ADVECTION THROUGH THE NIGHT WITH AT LEAST SOME WAA AS
WELL. THERE DOES NOT APPEAR TO BE MUCH IN THE WAY OF ORGANIZED
LIFT MOVING THROUGH, THEREFORE THE SHOWERS DURING THE DAY SHOULD
DECREASE IN AREAL COVERAGE.
HOWEVER, AS THE FLOW VEERS AND MOISTURE INCREASES IN THE LOWER
LEVELS SOME MODEL GUIDANCE INDICATES THAT THIS MOISTURE GENERALLY
BECOMES LOCKED IN THE LOWEST LEVELS. IF ENOUGH DRYING CAN OCCUR
ABOVE THIS, THEN SOME DRIZZLE MAY BE THE MAIN PRECIPITATION TYPE
DURING THE COURSE OF THE NIGHT. THIS COULD BE MAINLY FOR OUR
CENTRAL AND NORTHERN ZONES, AS FARTHER SOUTH ENOUGH WARMING MAY
RESULT IN THE CLOUD BASES RISING SOME AND A LESS CONDUCIVE SETUP
FOR DRIZZLE. WE NOTICED THAT SOME OF THE HIGH RESOLUTION GUIDANCE
INDICATES LITTLE TO NO PRECIPITATION OCCURRING DURING THE NIGHT,
WITH PERHAPS SOME SHOWERS DEVELOPING TOWARD DAYBREAK AS SOME
PVA/LIFT ARRIVES FROM THE SOUTHWEST WITH THE MID LEVEL FEATURE. AS
A RESULT, WE LOWERED POPS INTO THE CHC RANGE AND CARRIED SHOWERS
FAR SOUTH WITH LIGHT RAIN/DRIZZLE FARTHER NORTH. WE ALSO ADDED IN
PATCHY FOG, FIRST STARTING IN THE HIGHER TERRAIN THEN TO OTHER
AREAS.
AS FOR LOW TEMPERATURES, WE MAINLY USED AN EVEN GFS/NAM MOS
BLEND. TEMPERATURES SHOULD BE ON THE MILD SIDE GIVEN THE CLOUDS
AND CONTINUED WAA. THERE IS A CHC THAT ESPECIALLY THE FAR SOUTHERN
AREAS HAVE SOME INCREASE IN THE TEMPERATURES OVERNIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX WELL
TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI RIVER
VALLEY ON MONDAY. THERE SHOULD BE A RIDGE EXTENDING FROM THE
SOUTHEASTERN STATES TO THE GREAT LAKES. THE POLAR VORTEX WILL
REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA DURING THE NEW
WEEK. MEANWHILE, THE CLOSED LOW TO OUR WEST AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD, GRADUALLY SQUEEZING THE RIDGE AND
PUSHING IT OUT OVER THE ATLANTIC. AS THE TROUGH BEGINS TO MOVE
TOWARD THE EASTERN STATES, IT SHOULD START TO INTERACT WITH THE
POLAR VORTEX AROUND WEDNESDAY AS THAT FEATURE`S INFLUENCE BEGINS
TO EXPAND TO THE WEST AND SOUTH. THE RESULTING MID LEVEL TROUGH
WILL LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES AND THE
NORTHEASTERN STATES IN THE THURSDAY THROUGH SATURDAY TIME FRAME.
THE SURFACE FLOW IS FORECAST TO VEER TO THE SOUTH AND SOUTHWEST
FOR MONDAY AND MONDAY NIGHT CAUSING THE CLOUDS TO LIFT AND
TEMPERATURES TO WARM, RESULTING IN THE DEVELOPMENT OF UNSTABLE
CONDITIONS, ESPECIALLY AWAY FROM THE OCEAN. SURFACE BASED CAPE
VALUES ARE ANTICIPATED TO RISE NEAR 1000 J/KG IN OUR WESTERN
COUNTIES DURING THE AFTERNOON. A FAIR AMOUNT OF LOW LEVEL MOISTURE
WILL REMAIN IN OUR REGION. AS A RESULT, WE WILL CONTINUE TO
MENTION A CHANCE OF SHOWERS FOR MONDAY AND WE WILL ALSO INCLUDE
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS. THE GUIDANCE IS
INDICATING A DECREASE IN PRECIPITATION FOR MONDAY NIGHT WITH THE
LOSS OF DAYTIME HEATING AND WITH THE LACK OF ANY FOCUSING
MECHANISM.
TEMPERATURES ARE FORECAST TO RISE NEAR +15C AT 850 HPA FOR
TUESDAY. A SOUTH TO SOUTHWEST SURFACE FLOW WILL CONTINUE AND
TEMPERATURES ARE EXPECTED TO RISE INTO THE LOWER AND MIDDLE 80S IN
MUCH OF OUR FORECAST AREA. LINGERING LOW LEVEL MOISTURE WILL HELP
ENHANCE THE INSTABILITY AND WE ARE ANTICIPATING SCATTERED SHOWERS
AND THUNDERSTORMS, ESPECIALLY IN THE AFTERNOON AND EVENING.
SURFACE BASED CAPE VALUES IN THE 1500 J/KG NEIGHBORHOOD ARE
POSSIBLE IN OUR SOUTHWESTERN COUNTIES. THE MOST UNSTABLE AREAS
WILL LIKELY HAVE PRECIPITABLE WATER VALUES IN EXCESS OF 1.5 INCHES
WITH THERE BEING THE POTENTIAL FOR LOCALIZED DOWNPOURS.
A FRONTAL BOUNDARY IS FORECAST TO DROP INTO OUR REGION FROM THE
NORTH LATE ON TUESDAY. THERE IS A FAIR AMOUNT OF UNCERTAINTY AS TO
HOW FAR SOUTH THE BOUNDARY WILL PROGRESS. IT SHOULD CONTINUE TO
HAVE A LEAST A LITTLE MOMENTUM INTO WEDNESDAY. HOWEVER, AS THE MID
LEVEL RIDGE AXIS PASSES OVERHEAD ON WEDNESDAY OR WEDNESDAY NIGHT,
THE BOUNDARY IS EXPECTED TO BEGIN LIFTING BACK TO THE NORTH.
REGARDLESS, UNSETTLED CONDITIONS WILL LIKELY CONTINUE.
AS THE MID LEVEL TROUGH BEGINS TO INFLUENCE OUR REGION LATE IN
THE WEEK IT SHOULD MOVE A COLD FRONT ACROSS THE NORTHEASTERN
STATES ON FRIDAY. AS A RESULT, WE WILL CARRY A CHANCE OF SHOWERS
AND AFTERNOON THUNDERSTORMS FOR FRIDAY.
WHILE THERE WILL BE A CHANCE OF PRECIPITATION IN THE FORECAST FOR
EACH DAY FROM MONDAY THROUGH FRIDAY, THE WEEK SHOULD NOT BE A
TOTAL WASHOUT. ACTUALLY, MOST OF THE TIME PRECIPITATION WILL NOT
BE FALLING. OVERALL, TEMPERATURES FOR THE WEEK SHOULD AVERAGE
ABOVE NORMAL FOR THIS TIME OF THE YEAR.
AFTER THE COLD FRONT PASSES, DRY AIR IS ANTICIPATED TO BEGIN
BUILDING INTO OUR REGION FROM THE NORTHWEST AND NORTH FOR FRIDAY
NIGHT AND SATURDAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...MVFR/IFR CEILINGS PREVAIL THROUGH THE DAY, AND THERE IS
LOWER CONFIDENCE REGARDING ANY IMPROVEMENTS. IT IS POSSIBLE THAT
TERMINALS WITH IFR CEILINGS IMPROVE TO MVFR IN THE AFTERNOON, AND
THE VISIBILITIES SHOULD BE MOSTLY DEPENDENT ON THE SHOWERS.
SOUTHEAST WINDS GENERALLY NEAR 10 KNOTS.
TONIGHT...IFR CEILINGS, WITH A CHANCE FOR IMPROVEMENT TO MVFR
AT TIMES MAINLY SOUTH AND EAST OF KILG. OVERALL, SOME SHOWERS
SHOULD BE AROUND ESPECIALLY IN THE EVENING WITH EVEN THIS PERHAPS
TRANSITIONING TO SOME DRIZZLE, THEREFORE TIMES OF LOCAL VISIBILITY
RESTRICTIONS SHOULD OCCUR. SOME FOG IS ANTICIPATED WHICH WILL ALSO
LOWER THE LOCAL VISIBILITY, ALTHOUGH WE ARE CURRENTLY NOT
ANTICIPATING FOG TO REDUCE THE VISIBILITY TO UNDER 1SM. SOUTHEAST
WINDS 4-8 KNOTS, SHOULD TURN MORE SOUTH-SOUTHWEST.
OUTLOOK...
MONDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGH THE PERIOD WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
&&
.MARINE...
HIGH PRESSURE REMAINING TO OUR NORTHEAST TODAY WILL MAINTAIN A
SOUTHEASTERLY FLOW, ALTHOUGH THIS SHOULD START TO TURN MORE FROM
THE SOUTH LATER TODAY ACROSS THE SOUTHERN WATERS. THIS SHIFT TO
SOUTHERLY SHOULD THEN OVERSPREAD ALL THE WATERS TONIGHT. THIS FLOW
REGIME, WHICH IS ANTICIPATED TO REMAIN UNDER 25 KNOTS, WILL ALLOW
THE SEAS TO BUILD SOME MORE THOUGH. THE WAVEWATCH GUIDANCE HAS
BEEN RUNNING 1-2 FEET TO HIGH, HOWEVER IT IS CATCHING UP AS SEAS
REACHED 5 FEET EARLIER AT BUOY 44009. THESE HIGHER SEAS ARE
ANTICIPATED TO SPREAD NORTHWARD TODAY, HOWEVER CONFIDENCE IS NOT
ALL THAT HIGH THEY GET ABOVE 6 FEET. THEREFORE, THE SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR OUR OCEAN ZONES THROUGH TONIGHT.
THE CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA
ON DELAWARE BAY. SOME ADDITIONAL INCREASE IN THE DEW POINTS
TONIGHT COULD RESULT IN SOME FOG DEVELOPMENT.
OUTLOOK...
HIGH PRESSURE TO OUR NORTHEAST AND EAST WILL CONTINUE TO
INFLUENCE THE COASTAL WATERS OF NEW JERSEY AND DELAWARE INTO
TUESDAY. A FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP
INTO OUR REGION ON TUESDAY NIGHT BEFORE RETREATING BACK TO THE
NORTH ON WEDNESDAY AND THURSDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM MONDAY
THROUGH THURSDAY. WAVE HEIGHTS ON OUR OCEAN WATERS COULD REMAIN
AROUND 5 FEET ON MONDAY INTO MONDAY NIGHT AND THE CURRENT SMALL
CRAFT ADVISORY MAY NEED TO BE EXTENDED TO COVER THAT PERIOD. A
LULL IN WAVE HEIGHTS IS POSSIBLE FOR TUESDAY AND WEDNESDAY WITH 5
FOOT SEAS FORECAST TO RETURN TO OUR OCEAN WATERS FOR THURSDAY AS A
LONG SOUTHERLY FETCH BECOMES ESTABLISHED ALONG THE EAST COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...PO
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
000
FXUS61 KPHI 190954
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
554 AM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND
DISSIPATE AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. MEANWHILE,
HIGH PRESSURE SHOULD REMAIN TO OUR NORTHEAST AND EAST. ANOTHER
FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO OUR
REGION LATE ON TUESDAY AND IT SHOULD LIFT BACK TO THE NORTH ON
WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS THEN EXPECTED
TO ARRIVE ON FRIDAY, FOLLOWED BY HIGH PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN 08Z SURFACE ANALYSIS PLACED THE CENTER OF HIGH PRESSURE FROM
JUST NORTH OF NEW ENGLAND AND THEN WELL TO OUR EAST. A FRONTAL
BOUNDARY REMAINED DRAPED FROM NORTH CAROLINA NORTHWESTWARD TO THE
UPPER OHIO VALLEY THEN BACK INTO THE MIDWEST. A WEAK SURFACE
TROUGH WAS NOTED ACROSS THE DELMARVA. AN UPPER AIR ANALYSIS PLACED
A TROUGH IN THE WEST TO THE PLAINS, WITH A RIDGE TO ITS EAST. A
TROUGH WAS NEAR NORTHERN NEW ENGLAND, AND A MID LEVEL FEATURE WAS
NEAR THE CENTRAL APPALACHIANS. THERE WERE SEVERAL AREAS OF FOCUSED
850 MB FROM THE SOUTHERN PLAINS TOWARD THE MIDWEST, WITH A SMALL
AREA FROM LONG ISLAND TO WESTERN NEW YORK.
THE POPS WERE ADJUSTED DOWN SOME FOR AWHILE THIS MORNING AS RADAR
TRENDS ARE SHOWING A DECREASE IN AREAL COVERAGE. WHAT IS LEFT ATTM
LOOKS TO BE MOSTLY SOME POCKETS OF LIGHT RAIN AND DRIZZLE. WE LEFT
THE WORDING HOWEVER AS SHOWERY FOR NOW ESPECIALLY GIVEN THE POP
VALUES. THE HOURLY GRIDS WILL BE TWEAKED, BUT OVERALL NO MAJOR
CHANGES NEEDED AS A NEARLY STATE STATE REMAINS EARLY THIS MORNING.
OTHERWISE, OUR WEATHER WILL BE DOMINATED BY A MID LEVEL FEATURE
THAT NEARS THE MID ATLANTIC TOWARD EVENING. AT THE SURFACE, HIGH
PRESSURE WILL REMAIN TO OUR NORTHEAST AND EAST WHICH MAINTAINS A
SOUTHEASTERLY FLOW. AS WE GO UPSTAIRS HOWEVER, THE FLOW IS
FORECAST TO BE MORE SOUTHERLY TODAY AND THIS WILL ASSIST IN THE
MOISTURE ADVECTION. THERE CONTINUES TO BE LOW-LEVEL WAA FORECAST
THROUGH THE DAY. THIS WILL HELP TO MAINTAIN AT LEAST SOME
ISENTROPIC LIFT AS THE MORE STABLE MARINE INFLUENCED AIR MASS
RESIDES BELOW SOME WARMING. THE MODEL GUIDANCE CONTINUES TO SHOW
DECENT 850 MB AND 700 MB THETA-E ADVECTION. THE EARLIER NORTHWARD
PUSH OF SHOWERS APPEARED TO BE ALIGNED ALONG THE LEADING EDGE OF
THE 850 MB THETA-E SURGE. THE WEAKER LIFT IS RESULTING IN SOME
DRIZZLE EARLY THIS MORNING GIVEN THE RATHER MOIST LOW LEVELS.
OVERALL, WE WILL CARRY MAINLY CHC POPS FOR AWHILE THIS MORNING
WITH SOME INCREASE TO LOW LIKELY FOR MOST THROUGH THE DAY. OUR
CONFIDENCE IS ON THE LOWER SIDE THOUGH REGARDING THE OVERALL AREAL
COVERAGE THROUGH THE DAY.
OVERALL, TODAY WILL FEATURE A WEALTH OF LOW-LEVEL MOISTURE
COMBINED WITH THE ONSHORE FLOW RESULTING IN AN ABUNDANCE OF
CLOUDS. WE CAN HOPE FOR SOME BREAKS OF SUNSHINE, BUT THE MAJORITY
OF OUR CWA SHOULD MAINTAIN A CLOUDY SKY. THERE IS THE POTENTIAL
THAT OUR FAR SOUTHERN ZONES GET A FEW BREAKS OF SUNSHINE AS WARMER
AIR ARRIVES HERE COMPARED TO ELSEWHERE. THE FORECAST SOUNDINGS ARE
SHOWING SOME INSTABILITY DEVELOPING MAINLY FROM ABOUT MIDDAY ON
ACROSS PORTIONS OF THE DELMARVA. THIS COULD RESULT IN SOME
THUNDER, HOWEVER AS OF NOW WE OPTED TO LEAVE OUT A MENTION AS IT
WOULD PROBABLY BE RATHER ISOLATED AND CONFIDENCE IS NOT ALL THAT
HIGH.
AS FOR HIGH TEMPERATURES, WE OPTED TO GO WITH THE COOLER GFS MOS
WITH EVEN SOME TWEAKS DOWNWARD A BIT. THIS IS BASED ON A SOLID
CLOUD DECK REMAINING WITH MOSTLY A SOUTHEAST FLOW CONTINUING. THE
WARMEST TEMPERATURES WERE PLACED ACROSS PORTIONS OF DELAWARE AND
MARYLAND AS THE WINDS MAY TURN MORE SOUTHERLY HERE SOONER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE AFOREMENTIONED MID LEVEL FEATURE LOOKS TO LINGER NEAR THE MID
ATLANTIC TONIGHT, AS A RIDGE ALOFT GRADUALLY SLIDES EASTWARD. HIGH
PRESSURE AT THE SURFACE AS A RESULT IS FORECAST TO SLIDE FARTHER
TO OUR EAST, WHICH WILL ALLOW THE LOW-LEVEL FLOW TO VEER FROM
SOUTHEAST TO MORE SOUTH OR SOUTHWEST OVERNIGHT. THIS MAINTAINS
THETA-E ADVECTION THROUGH THE NIGHT WITH AT LEAST SOME WAA AS
WELL. THERE DOES NOT APPEAR TO BE MUCH IN THE WAY OF ORGANIZED
LIFT MOVING THROUGH, THEREFORE THE SHOWERS DURING THE DAY SHOULD
DECREASE IN AREAL COVERAGE.
HOWEVER, AS THE FLOW VEERS AND MOISTURE INCREASES IN THE LOWER
LEVELS SOME MODEL GUIDANCE INDICATES THAT THIS MOISTURE GENERALLY
BECOMES LOCKED IN THE LOWEST LEVELS. IF ENOUGH DRYING CAN OCCUR
ABOVE THIS, THEN SOME DRIZZLE MAY BE THE MAIN PRECIPITATION TYPE
DURING THE COURSE OF THE NIGHT. THIS COULD BE MAINLY FOR OUR
CENTRAL AND NORTHERN ZONES, AS FARTHER SOUTH ENOUGH WARMING MAY
RESULT IN THE CLOUD BASES RISING SOME AND A LESS CONDUCIVE SETUP
FOR DRIZZLE. WE NOTICED THAT SOME OF THE HIGH RESOLUTION GUIDANCE
INDICATES LITTLE TO NO PRECIPITATION OCCURRING DURING THE NIGHT,
WITH PERHAPS SOME SHOWERS DEVELOPING TOWARD DAYBREAK AS SOME
PVA/LIFT ARRIVES FROM THE SOUTHWEST WITH THE MID LEVEL FEATURE. AS
A RESULT, WE LOWERED POPS INTO THE CHC RANGE AND CARRIED SHOWERS
FAR SOUTH WITH LIGHT RAIN/DRIZZLE FARTHER NORTH. WE ALSO ADDED IN
PATCHY FOG, FIRST STARTING IN THE HIGHER TERRAIN THEN TO OTHER
AREAS.
AS FOR LOW TEMPERATURES, WE MAINLY USED AN EVEN GFS/NAM MOS
BLEND. TEMPERATURES SHOULD BE ON THE MILD SIDE GIVEN THE CLOUDS
AND CONTINUED WAA. THERE IS A CHC THAT ESPECIALLY THE FAR SOUTHERN
AREAS HAVE SOME INCREASE IN THE TEMPERATURES OVERNIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX WELL
TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI RIVER
VALLEY ON MONDAY. THERE SHOULD BE A RIDGE EXTENDING FROM THE
SOUTHEASTERN STATES TO THE GREAT LAKES. THE POLAR VORTEX WILL
REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA DURING THE NEW
WEEK. MEANWHILE, THE CLOSED LOW TO OUR WEST AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD, GRADUALLY SQUEEZING THE RIDGE AND
PUSHING IT OUT OVER THE ATLANTIC. AS THE TROUGH BEGINS TO MOVE
TOWARD THE EASTERN STATES, IT SHOULD START TO INTERACT WITH THE
POLAR VORTEX AROUND WEDNESDAY AS THAT FEATURE`S INFLUENCE BEGINS
TO EXPAND TO THE WEST AND SOUTH. THE RESULTING MID LEVEL TROUGH
WILL LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES AND THE
NORTHEASTERN STATES IN THE THURSDAY THROUGH SATURDAY TIME FRAME.
THE SURFACE FLOW IS FORECAST TO VEER TO THE SOUTH AND SOUTHWEST
FOR MONDAY AND MONDAY NIGHT CAUSING THE CLOUDS TO LIFT AND
TEMPERATURES TO WARM, RESULTING IN THE DEVELOPMENT OF UNSTABLE
CONDITIONS, ESPECIALLY AWAY FROM THE OCEAN. SURFACE BASED CAPE
VALUES ARE ANTICIPATED TO RISE NEAR 1000 J/KG IN OUR WESTERN
COUNTIES DURING THE AFTERNOON. A FAIR AMOUNT OF LOW LEVEL MOISTURE
WILL REMAIN IN OUR REGION. AS A RESULT, WE WILL CONTINUE TO
MENTION A CHANCE OF SHOWERS FOR MONDAY AND WE WILL ALSO INCLUDE
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS. THE GUIDANCE IS
INDICATING A DECREASE IN PRECIPITATION FOR MONDAY NIGHT WITH THE
LOSS OF DAYTIME HEATING AND WITH THE LACK OF ANY FOCUSING
MECHANISM.
TEMPERATURES ARE FORECAST TO RISE NEAR +15C AT 850 HPA FOR
TUESDAY. A SOUTH TO SOUTHWEST SURFACE FLOW WILL CONTINUE AND
TEMPERATURES ARE EXPECTED TO RISE INTO THE LOWER AND MIDDLE 80S IN
MUCH OF OUR FORECAST AREA. LINGERING LOW LEVEL MOISTURE WILL HELP
ENHANCE THE INSTABILITY AND WE ARE ANTICIPATING SCATTERED SHOWERS
AND THUNDERSTORMS, ESPECIALLY IN THE AFTERNOON AND EVENING.
SURFACE BASED CAPE VALUES IN THE 1500 J/KG NEIGHBORHOOD ARE
POSSIBLE IN OUR SOUTHWESTERN COUNTIES. THE MOST UNSTABLE AREAS
WILL LIKELY HAVE PRECIPITABLE WATER VALUES IN EXCESS OF 1.5 INCHES
WITH THERE BEING THE POTENTIAL FOR LOCALIZED DOWNPOURS.
A FRONTAL BOUNDARY IS FORECAST TO DROP INTO OUR REGION FROM THE
NORTH LATE ON TUESDAY. THERE IS A FAIR AMOUNT OF UNCERTAINTY AS TO
HOW FAR SOUTH THE BOUNDARY WILL PROGRESS. IT SHOULD CONTINUE TO
HAVE A LEAST A LITTLE MOMENTUM INTO WEDNESDAY. HOWEVER, AS THE MID
LEVEL RIDGE AXIS PASSES OVERHEAD ON WEDNESDAY OR WEDNESDAY NIGHT,
THE BOUNDARY IS EXPECTED TO BEGIN LIFTING BACK TO THE NORTH.
REGARDLESS, UNSETTLED CONDITIONS WILL LIKELY CONTINUE.
AS THE MID LEVEL TROUGH BEGINS TO INFLUENCE OUR REGION LATE IN
THE WEEK IT SHOULD MOVE A COLD FRONT ACROSS THE NORTHEASTERN
STATES ON FRIDAY. AS A RESULT, WE WILL CARRY A CHANCE OF SHOWERS
AND AFTERNOON THUNDERSTORMS FOR FRIDAY.
WHILE THERE WILL BE A CHANCE OF PRECIPITATION IN THE FORECAST FOR
EACH DAY FROM MONDAY THROUGH FRIDAY, THE WEEK SHOULD NOT BE A
TOTAL WASHOUT. ACTUALLY, MOST OF THE TIME PRECIPITATION WILL NOT
BE FALLING. OVERALL, TEMPERATURES FOR THE WEEK SHOULD AVERAGE
ABOVE NORMAL FOR THIS TIME OF THE YEAR.
AFTER THE COLD FRONT PASSES, DRY AIR IS ANTICIPATED TO BEGIN
BUILDING INTO OUR REGION FROM THE NORTHWEST AND NORTH FOR FRIDAY
NIGHT AND SATURDAY.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...MVFR/IFR CEILINGS PREVAIL THROUGH THE DAY, AND THERE IS
LOWER CONFIDENCE REGARDING ANY IMPROVEMENTS. IT IS POSSIBLE THAT
TERMINALS WITH IFR CEILINGS IMPROVE TO MVFR IN THE AFTERNOON, AND
THE VISIBILITIES SHOULD BE MOSTLY DEPENDENT ON THE SHOWERS.
SOUTHEAST WINDS GENERALLY NEAR 10 KNOTS.
TONIGHT...IFR CEILINGS, WITH A CHANCE FOR IMPROVEMENT TO MVFR
AT TIMES MAINLY SOUTH AND EAST OF KILG. OVERALL, SOME SHOWERS
SHOULD BE AROUND ESPECIALLY IN THE EVENING WITH EVEN THIS PERHAPS
TRANSITIONING TO SOME DRIZZLE, THEREFORE TIMES OF LOCAL VISIBILITY
RESTRICTIONS SHOULD OCCUR. SOME FOG IS ANTICIPATED WHICH WILL ALSO
LOWER THE LOCAL VISIBILITY, ALTHOUGH WE ARE CURRENTLY NOT
ANTICIPATING FOG TO REDUCE THE VISIBILITY TO UNDER 1SM. SOUTHEAST
WINDS 4-8 KNOTS, SHOULD TURN MORE SOUTH-SOUTHWEST.
OUTLOOK...
MONDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGH THE PERIOD WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
&&
.MARINE...
HIGH PRESSURE REMAINING TO OUR NORTHEAST TODAY WILL MAINTAIN A
SOUTHEASTERLY FLOW, ALTHOUGH THIS SHOULD START TO TURN MORE FROM
THE SOUTH LATER TODAY ACROSS THE SOUTHERN WATERS. THIS SHIFT TO
SOUTHERLY SHOULD THEN OVERSPREAD ALL THE WATERS TONIGHT. THIS FLOW
REGIME, WHICH IS ANTICIPATED TO REMAIN UNDER 25 KNOTS, WILL ALLOW
THE SEAS TO BUILD SOME MORE THOUGH. THE WAVEWATCH GUIDANCE HAS
BEEN RUNNING 1-2 FEET TO HIGH, HOWEVER IT IS CATCHING UP AS SEAS
REACHED 5 FEET EARLIER AT BUOY 44009. THESE HIGHER SEAS ARE
ANTICIPATED TO SPREAD NORTHWARD TODAY, HOWEVER CONFIDENCE IS NOT
ALL THAT HIGH THEY GET ABOVE 6 FEET. THEREFORE, THE SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR OUR OCEAN ZONES THROUGH TONIGHT.
THE CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA
ON DELAWARE BAY. SOME ADDITIONAL INCREASE IN THE DEW POINTS
TONIGHT COULD RESULT IN SOME FOG DEVELOPMENT.
OUTLOOK...
HIGH PRESSURE TO OUR NORTHEAST AND EAST WILL CONTINUE TO
INFLUENCE THE COASTAL WATERS OF NEW JERSEY AND DELAWARE INTO
TUESDAY. A FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP
INTO OUR REGION ON TUESDAY NIGHT BEFORE RETREATING BACK TO THE
NORTH ON WEDNESDAY AND THURSDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM MONDAY
THROUGH THURSDAY. WAVE HEIGHTS ON OUR OCEAN WATERS COULD REMAIN
AROUND 5 FEET ON MONDAY INTO MONDAY NIGHT AND THE CURRENT SMALL
CRAFT ADVISORY MAY NEED TO BE EXTENDED TO COVER THAT PERIOD. A
LULL IN WAVE HEIGHTS IS POSSIBLE FOR TUESDAY AND WEDNESDAY WITH 5
FOOT SEAS FORECAST TO RETURN TO OUR OCEAN WATERS FOR THURSDAY AS A
LONG SOUTHERLY FETCH BECOMES ESTABLISHED ALONG THE EAST COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ450>452.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ453>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
000
FXUS61 KPHI 190748
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
348 AM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE NORTH CENTRAL STATES, ACROSS
THE OHIO RIVER VALLEY TO THE WATERS OFF NORTH CAROLINA EARLY THIS
MORNING. THE BOUNDARY IS EXPECTED TO WEAKEN AND DISSIPATE AS IT
MEANDERS OVER THE SAME GENERAL AREA THROUGH MONDAY. MEANWHILE,
HIGH PRESSURE SHOULD REMAIN TO OUR NORTHEAST AND EAST. ANOTHER
FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO OUR
REGION LATE ON TUESDAY AND IT SHOULD LIFT BACK TO THE NORTH ON
WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED TO
ARRIVE ON FRIDAY, FOLLOWED BY HIGH PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 06Z SURFACE ANALYSIS PLACED THE CENTER OF HIGH PRESSURE FROM
JUST NORTH OF NEW ENGLAND AND THEN WELL TO OUR EAST. A FRONTAL
BOUNDARY REMAINED DRAPED FROM NORTH CAROLINA NORTHWESTWARD TO THE
UPPER OHIO VALLEY THEN BACK INTO THE MIDWEST. A WEAK SURFACE
TROUGH WAS NOTED ACROSS THE DELMARVA. AN UPPER AIR ANALYSIS PLACED
A TROUGH IN THE WEST TO THE PLAINS, WITH A RIDGE TO ITS EAST. A
TROUGH WAS NEAR NORTHERN NEW ENGLAND, AND A MID LEVEL FEATURE WAS
NEAR THE CENTRAL APPALACHIANS. THERE WERE SEVERAL AREAS OF FOCUSED
850 MB FROM THE SOUTHERN PLAINS TOWARD THE MIDWEST, WITH A SMALL
AREA FROM LONG ISLAND TO WESTERN NEW YORK.
OUR WEATHER WILL BE DOMINATED BY A MID LEVEL FEATURE THAT NEARS
THE MID ATLANTIC TOWARD EVENING. AT THE SURFACE, HIGH PRESSURE
WILL REMAIN TO OUR NORTHEAST AND EAST WHICH MAINTAINS A
SOUTHEASTERLY FLOW. AS WE GO UPSTAIRS HOWEVER, THE FLOW IS
FORECAST TO BE MORE SOUTHERLY TODAY AND THIS WILL ASSIST IN THE
MOISTURE ADVECTION. THERE CONTINUES TO BE LOW-LEVEL WAA FORECAST
THROUGH THE DAY. THIS WILL HELP TO MAINTAIN AT LEAST SOME
ISENTROPIC LIFT AS THE MORE STABLE MARINE INFLUENCED AIR MASS
RESIDES BELOW SOME WARMING. THE MODEL GUIDANCE CONTINUES TO SHOW
DECENT 850 MB AND 700 MB THETA-E ADVECTION. THE EARLIER NORTHWARD
PUSH OF SHOWERS APPEARED TO BE ALIGNED ALONG THE LEADING EDGE OF
THE 850 MB THETA-E SURGE. THIS IS FORECAST TO SPREAD NORTHWARD,
AND THE SHOWERS ARE FOLLOWING THIS. THE WEAKER LIFT IS ALSO
RESULTING IN SOME DRIZZLE EARLY THIS MORNING GIVEN THE RATHER
MOIST LOW LEVELS. OVERALL, WE WILL CARRY CHC TO LOW LIKELY POPS
FOR SHOWERS THROUGH THE DAY AS CONFIDENCE IS ON THE LOWER SIDE
REGARDING ANY REAL ORGANIZED ACTIVITY.
OVERALL, TODAY WILL FEATURE A WEALTH OF LOW-LEVEL MOISTURE
COMBINED WITH THE ONSHORE FLOW RESULTING IN AN ABUNDANCE OF
CLOUDS. WE CAN HOPE FOR SOME BREAKS OF SUNSHINE, BUT THE MAJORITY
OF OUR CWA SHOULD MAINTAIN A CLOUDY SKY. THERE IS THE POTENTIAL
THAT OUR FAR SOUTHERN ZONES GET A FEW BREAKS OF SUNSHINE AS WARMER
AIR ARRIVES HERE COMPARED TO ELSEWHERE. THE FORECAST SOUNDINGS ARE
SHOWING SOME INSTABILITY DEVELOPING MAINLY FROM ABOUT MIDDAY ON
ACROSS PORTIONS OF THE DELMARVA. THIS COULD RESULT IN SOME
THUNDER, HOWEVER AS OF NOW WE OPTED TO LEAVE OUT A MENTION AS IT
WOULD PROBABLY BE RATHER ISOLATED AND CONFIDENCE IS NOT ALL THAT
HIGH.
AS FOR HIGH TEMPERATURES, WE OPTED TO GO WITH THE COOLER GFS MOS
WITH EVEN SOME TWEAKS DOWNWARD A BIT. THIS IS BASED ON A SOLID
CLOUD DECK REMAINING WITH MOSTLY A SOUTHEAST FLOW CONTINUING. THE
WARMEST TEMPERATURES WERE PLACED ACROSS PORTIONS OF DELAWARE AND
MARYLAND AS THE WINDS MAY TURN MORE SOUTHERLY HERE SOONER. WE USED
SOME OF THE LAMP/LAV GUIDANCE IN THE HOURLY TEMPERATURE GRIDS,
ESPECIALLY FOR AWHILE THIS MORNING, TO HELP WITH THE TRENDS
INCLUDING STEADIER VALUES FOR MOST PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE AFOREMENTIONED MID LEVEL FEATURE LOOKS TO LINGER NEAR THE MID
ATLANTIC TONIGHT, AS A RIDGE ALOFT GRADUALLY SLIDES EASTWARD. HIGH
PRESSURE AT THE SURFACE AS A RESULT IS FORECAST TO SLIDE FARTHER
TO OUR EAST, WHICH WILL ALLOW THE LOW-LEVEL FLOW TO VEER FROM
SOUTHEAST TO MORE SOUTH OR SOUTHWEST OVERNIGHT. THIS MAINTAINS
THETA-E ADVECTION THROUGH THE NIGHT WITH AT LEAST SOME WAA AS
WELL. THERE DOES NOT APPEAR TO BE MUCH IN THE WAY OF ORGANIZED
LIFT MOVING THROUGH, THEREFORE THE SHOWERS DURING THE DAY SHOULD
DECREASE IN AREAL COVERAGE.
HOWEVER, AS THE FLOW VEERS AND MOISTURE INCREASES IN THE LOWER
LEVELS SOME MODEL GUIDANCE INDICATES THAT THIS MOISTURE GENERALLY
BECOMES LOCKED IN THE LOWEST LEVELS. IF ENOUGH DRYING CAN OCCUR
ABOVE THIS, THEN SOME DRIZZLE MAY BE THE MAIN PRECIPITATION TYPE
DURING THE COURSE OF THE NIGHT. THIS COULD BE MAINLY FOR OUR
CENTRAL AND NORTHERN ZONES, AS FARTHER SOUTH ENOUGH WARMING MAY
RESULT IN THE CLOUD BASES RISING SOME AND A LESS CONDUCIVE SETUP
FOR DRIZZLE. WE NOTICED THAT SOME OF THE HIGH RESOLUTION GUIDANCE
INDICATES LITTLE TO NO PRECIPITATION OCCURRING DURING THE NIGHT,
WITH PERHAPS SOME SHOWERS DEVELOPING TOWARD DAYBREAK AS SOME
PVA/LIFT ARRIVES FROM THE SOUTHWEST WITH THE MID LEVEL FEATURE. AS
A RESULT, WE LOWERED POPS INTO THE CHC RANGE AND CARRIED SHOWERS
FAR SOUTH WITH LIGHT RAIN/DRIZZLE FARTHER NORTH. WE ALSO ADDED IN
PATCHY FOG, FIRST STARTING IN THE HIGHER TERRAIN THEN TO OTHER
AREAS.
AS FOR LOW TEMPERATURES, WE MAINLY USED AN EVEN GFS/NAM MOS
BLEND. TEMPERATURES SHOULD BE ON THE MILD SIDE GIVEN THE CLOUDS
AND CONTINUED WAA. THERE IS A CHC THAT ESPECIALLY THE FAR SOUTHERN
AREAS HAVE SOME INCREASE IN THE TEMPERATURES OVERNIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX WELL
TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI RIVER
VALLEY ON MONDAY. THERE SHOULD BE A RIDGE EXTENDING FROM THE
SOUTHEASTERN STATES TO THE GREAT LAKES. THE POLAR VORTEX WILL
REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA DURING THE NEW
WEEK. MEANWHILE, THE CLOSED LOW TO OUR WEST AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD, GRADUALLY SQUEEZING THE RIDGE AND
PUSHING IT OUT OVER THE ATLANTIC. AS THE TROUGH BEGINS TO MOVE
TOWARD THE EASTERN STATES, IT SHOULD START TO INTERACT WITH THE
POLAR VORTEX AROUND WEDNESDAY AS THAT FEATURE`S INFLUENCE BEGINS
TO EXPAND TO THE WEST AND SOUTH. THE RESULTING MID LEVEL TROUGH
WILL LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES AND THE
NORTHEASTERN STATES IN THE THURSDAY THROUGH SATURDAY TIME FRAME.
THE SURFACE FLOW IS FORECAST TO VEER TO THE SOUTH AND SOUTHWEST
FOR MONDAY AND MONDAY NIGHT CAUSING THE CLOUDS TO LIFT AND
TEMPERATURES TO WARM, RESULTING IN THE DEVELOPMENT OF UNSTABLE
CONDITIONS, ESPECIALLY AWAY FROM THE OCEAN. SURFACE BASED CAPE
VALUES ARE ANTICIPATED TO RISE NEAR 1000 J/KG IN OUR WESTERN
COUNTIES DURING THE AFTERNOON. A FAIR AMOUNT OF LOW LEVEL MOISTURE
WILL REMAIN IN OUR REGION. AS A RESULT, WE WILL CONTINUE TO
MENTION A CHANCE OF SHOWERS FOR MONDAY AND WE WILL ALSO INCLUDE
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS. THE GUIDANCE IS
INDICATING A DECREASE IN PRECIPITATION FOR MONDAY NIGHT WITH THE
LOSS OF DAYTIME HEATING AND WITH THE LACK OF ANY FOCUSING
MECHANISM.
TEMPERATURES ARE FORECAST TO RISE NEAR +15C AT 850 HPA FOR
TUESDAY. A SOUTH TO SOUTHWEST SURFACE FLOW WILL CONTINUE AND
TEMPERATURES ARE EXPECTED TO RISE INTO THE LOWER AND MIDDLE 80S IN
MUCH OF OUR FORECAST AREA. LINGERING LOW LEVEL MOISTURE WILL HELP
ENHANCE THE INSTABILITY AND WE ARE ANTICIPATING SCATTERED SHOWERS
AND THUNDERSTORMS, ESPECIALLY IN THE AFTERNOON AND EVENING.
SURFACE BASED CAPE VALUES IN THE 1500 J/KG NEIGHBORHOOD ARE
POSSIBLE IN OUR SOUTHWESTERN COUNTIES. THE MOST UNSTABLE AREAS
WILL LIKELY HAVE PRECIPITABLE WATER VALUES IN EXCESS OF 1.5 INCHES
WITH THERE BEING THE POTENTIAL FOR LOCALIZED DOWNPOURS.
A FRONTAL BOUNDARY IS FORECAST TO DROP INTO OUR REGION FROM THE
NORTH LATE ON TUESDAY. THERE IS A FAIR AMOUNT OF UNCERTAINTY AS TO
HOW FAR SOUTH THE BOUNDARY WILL PROGRESS. IT SHOULD CONTINUE TO
HAVE A LEAST A LITTLE MOMENTUM INTO WEDNESDAY. HOWEVER, AS THE MID
LEVEL RIDGE AXIS PASSES OVERHEAD ON WEDNESDAY OR WEDNESDAY NIGHT,
THE BOUNDARY IS EXPECTED TO BEGIN LIFTING BACK TO THE NORTH.
REGARDLESS, UNSETTLED CONDITIONS WILL LIKELY CONTINUE.
AS THE MID LEVEL TROUGH BEGINS TO INFLUENCE OUR REGION LATE IN
THE WEEK IT SHOULD MOVE A COLD FRONT ACROSS THE NORTHEASTERN
STATES ON FRIDAY. AS A RESULT, WE WILL CARRY A CHANCE OF SHOWERS
AND AFTERNOON THUNDERSTORMS FOR FRIDAY.
WHILE THERE WILL BE A CHANCE OF PRECIPITATION IN THE FORECAST FOR
EACH DAY FROM MONDAY THROUGH FRIDAY, THE WEEK SHOULD NOT BE A
TOTAL WASHOUT. ACTUALLY, MOST OF THE TIME PRECIPITATION WILL NOT
BE FALLING. OVERALL, TEMPERATURES FOR THE WEEK SHOULD AVERAGE
ABOVE NORMAL FOR THIS TIME OF THE YEAR.
AFTER THE COLD FRONT PASSES, DRY AIR IS ANTICIPATED TO BEGIN
BUILDING INTO OUR REGION FROM THE NORTHWEST AND NORTH FOR FRIDAY
NIGHT AND SATURDAY.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...MVFR/IFR CEILINGS PREVAIL THROUGH THE DAY, AND THERE IS
LOWER CONFIDENCE REGARDING ANY IMPROVEMENTS. IT IS POSSIBLE THAT
TERMINALS WITH IFR CEILINGS IMPROVE TO MVFR IN THE AFTERNOON, AND
THE VISIBILITIES SHOULD BE MOSTLY DEPENDENT ON THE SHOWERS.
SOUTHEAST WINDS GENERALLY NEAR 10 KNOTS.
TONIGHT...IFR CEILINGS, WITH THE POTENTIAL FOR SOME IMPROVEMENT
TO MVFR ESPECIALLY SOUTH AND EAST OF KILG. OVERALL, SOME SHOWERS
SHOULD BE AROUND WITH EVEN THIS PERHAPS TRANSITIONING TO SOME
DRIZZLE, THEREFORE TIMES OF LOCAL VISIBILITY RESTRICTIONS. SOME
FOG IS ANTICIPATED WHICH WILL ALSO LOWER THE VISIBILITY, ALTHOUGH
WE ARE CURRENTLY NOT ANTICIPATING FOG TO REDUCE THE VISIBILITY TO
UNDER 1SM. SOUTHEAST WINDS 4-8 KNOTS, SHOULD TURN MORE SOUTH-
SOUTHWEST.
OUTLOOK...
MONDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGH THE PERIOD WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
&&
.MARINE...
HIGH PRESSURE REMAINING TO OUR NORTHEAST TODAY WILL MAINTAIN A
SOUTHEASTERLY FLOW, ALTHOUGH THIS SHOULD START TO TURN MORE FROM
THE SOUTH LATER TODAY ACROSS THE SOUTHERN WATERS. THIS SHIFT TO
SOUTHERLY SHOULD THEN OVERSPREAD ALL THE WATERS TONIGHT. THIS FLOW
REGIME, WHICH IS ANTICIPATED TO REMAIN UNDER 25 KNOTS, WILL ALLOW
THE SEAS TO BUILD SOME MORE THOUGH. THE WAVEWATCH GUIDANCE HAS
BEEN RUNNING 1-2 FEET TO HIGH, HOWEVER IT IS CATCHING UP AS SEAS
REACHED 5 FEET EARLIER AT BUOY 44009. THESE HIGHER SEAS ARE
ANTICIPATED TO SPREAD NORTHWARD TODAY, HOWEVER CONFIDENCE IS NOT
ALL THAT HIGH THEY GET ABOVE 6 FEET. THEREFORE, THE SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR OUR OCEAN ZONES THROUGH TONIGHT.
THE CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA
ON DELAWARE BAY. SOME ADDITIONAL INCREASE IN THE DEW POINTS
TONIGHT COULD RESULT IN SOME FOG DEVELOPMENT.
OUTLOOK...
HIGH PRESSURE TO OUR NORTHEAST AND EAST WILL CONTINUE TO
INFLUENCE THE COASTAL WATERS OF NEW JERSEY AND DELAWARE INTO
TUESDAY. A FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO DROP
INTO OUR REGION ON TUESDAY NIGHT BEFORE RETREATING BACK TO THE
NORTH ON WEDNESDAY AND THURSDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM MONDAY
THROUGH THURSDAY. WAVE HEIGHTS ON OUR OCEAN WATERS COULD REMAIN
AROUND 5 FEET ON MONDAY INTO MONDAY NIGHT AND THE CURRENT SMALL
CRAFT ADVISORY MAY NEED TO BE EXTENDED TO COVER THAT PERIOD. A
LULL IN WAVE HEIGHTS IS POSSIBLE FOR TUESDAY AND WEDNESDAY WITH 5
FOOT SEAS FORECAST TO RETURN TO OUR OCEAN WATERS FOR THURSDAY AS A
LONG SOUTHERLY FETCH BECOMES ESTABLISHED ALONG THE EAST COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ450>452.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ453>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
000
FXUS61 KPHI 190313
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1113 PM EDT SAT MAY 18 2013
.SYNOPSIS...
A STATIONARY FRONT TO OUR SOUTHWEST IS FORECAST TO SLOWLY DISSIPATE
THROUGH MONDAY. HIGH PRESSURE TO OUR NORTHEAST WILL DROP SOUTH AND
TAKE ON THE CHARACTERISTICS OF A BERMUDA HIGH. A FRONTAL BOUNDARY
FROM THE NORTH WILL APPROACH OUR AREA ON TUESDAY AND STALL NEARBY.
THE FRONT MAY LIFT BACK NORTH LATER IN THE WEEK. A COLD FRONT
APPROACHING FROM THE WEST MAY CROSS OUR AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE POPS WERE INCREASED INTO THE LIKELY RANGE FASTER ACROSS
PORTIONS OF SOUTHERN NEW JERSEY DOWN INTO DELAWARE GIVEN RADAR
TRENDS. THESE SHOWERS APPEAR TO BE FOCUSED ALONG A CONVERGENCE
ZONE WITHIN SOME LOW-LEVEL WAA, ALONG WITH PERHAPS SOME ENHANCEMENT
FROM AN UPPER-LEVEL JET. THESE MAY GRADUALLY DECREASE IN COVERAGE
FOR A TIME BEFORE RAMPING UP AGAIN LATE, BASED ON SOME SHORT TERM
MODEL GUIDANCE. QPF AMOUNTS WERE ALSO RAISED SOME MORE. THE
NORTHERN ZONES MAY END UP BEING RAINFREE FOR AWHILE, BUT WE WILL
STILL KEEP SOME LOWER POPS GOING.
OTHERWISE, PLENTY OF CLOUDS ALONG WITH A SOUTHEASTERLY FLOW SHOULD
KEEP TEMPERATURES NEARLY STEADY FOR THE OVERNIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE FRONT WILL BE SLOW TO CROSS THE AREA. A WEAK UPPER LOW WILL ALSO
BE INTERACTING WITH THE FRONT...SO ANOTHER DAY OF ABUNDANT
CLOUDINESS AND SCATTERED SHOWERS IS EXPECTED. WE WILL KEEP THE LOW
LIKELY POPS ACROSS THE AREA EARLY...THEN LOWER THEN AFTER THAT. THIS
IS MORE LIKE THE NAM STAT GUIDANCE...BUT CONFID IN THE AMOUNT/QPF
FOR SUNDAY IS RATHER LOW ATTM. HIGH TEMPERATURES WILL MOSTLY BE IN
THE MID TO UPPER 60S FAR NORTH...LOW 70S CENTRAL AREAS AND PERHAPS
INTO THE MID OR UPPER 70S FAR SOUTH...ESPECIALLY IF ANY BREAKS
DEVELOP IN THE CLOUDS LATE. QPF FCST...MOSTLY 1/10 TO 1/4 INCH WITH
THE HIGHER TOTALS ACROSS THE DELMARVA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
THE MID LEVELS STILL START WITH A VORTEX OVER EASTERN CANADA, A
RIDGE BUILDING FROM THE WESTERN ATLANTIC AND A LOW CROSSING THE
ROCKIES. THERE ALSO ARE THE REMAINS OF THE LOW THAT CAUSED THE SPLIT
FLOW EARLIER THIS WEEK, AND THEY ARE FORECAST TO MOVE SLOWLY TOWARD
AND THEN ACROSS OUR AREA INTO TUESDAY. IT LOOKS THOSE REMAINS AND
THE VORTEX TO THE NORTH WILL COMBINE TO KEEP THE RIDGE FROM BUILDING
TOO MUCH UP THE EASTERN SEABOARD THROUGH THE FIRST PART OF THE LONG
TERM, AND THEN THE LOW APPROACHING FROM THE WEST WILL BEGIN TO PUSH
THE RIDGE TO THE EAST. THAT LOW IS EXPECTED TO OPEN DURING THE
MID-WEEK PERIOD AND EVENTUALLY CROSS OUR LONGITUDE. WHETHER IS DOES
SO BEFORE THE END OF THE LONG TERM IS UP IN THE AIR. THE GFS KEEPS
SOMETHING OF A REX BLOCK OVER THE CENTER OF THE NATION GOING INTO
THURSDAY, AND IS THEREFORE NOT AS PROGRESSIVE AS THE ECMWF. THE 12Z
GEFS SUPPORT THE OPERATIONAL GFS, AND THE 00Z ECMWF ENSEMBLES
SUPPORT THE OPERATIONAL 00Z AND 12Z ECMWF. WE THEREFORE HAVE SIDED
WITH THE FORECAST FROM HPC, WHICH LEANS TOWARD THE LATTER SUITE AND
MAINTAINS DECENT CONTINUITY.
THE MODELS AGREE ON GRADUALLY MOVING THE CENTER OF SURFACE HIGH
PRESSURE FROM NORTH OF 40N TO SOUTH OF IT, AND THAT TRANSITIONS US
FROM A MARITIME FLOW WITH AN EASTERLY COMPONENT TO A MORE SOUTHERLY
AND HUMID FLOW AND A MORE (ESPECIALLY AWAY FROM THE OCEAN) UNSTABLE
FLOW. THE VORTEX TO THE NORTH STILL TRIES TO PUSH A COLD FRONT DOWN
INTO OUR AREA AROUND TUESDAY NIGHT, AND IT MAY STALL NEARBY. ALL THIS
WILL SEND US FROM A PERIOD OF SHOWERS TO A PERIOD WHEN THUNDERSTORMS
ARE POSSIBLE. AT THIS POINT, WE REALLY CAN`T CARVE OUT A TIME PERIOD
WHEN WE AREN`T CARRYING A CHANCE OF THUNDERSTORMS UNTIL THE SYSTEM
FROM THE WEST MOVES THROUGH WITH A SURFACE COLD FRONT. SINCE WE HAVE
SIDED WITH THE MORE PROGRESSIVE SOLUTION, OUR POPS DO DROP BELOW
CHANCE BY SATURDAY. AS NOTED BY THE PREVIOUS LONG TERM FORECASTER,
THUNDERSTORM ACTIVITY WILL NOT BE CONSTANT. IN THE ABSENCE OF ANY
FOCUSED ENERGY KICKING OUT OF THE SYSTEM TO THE WEST, ACTIVITY WOULD
BE MOST LIKELY DURING THE AFTERNOON AND EVENING HOURS.
NIGHTS ARE FORECAST TO BE WARMER THAN NORMAL AND RATHER HUMID UNTIL
THE FRONTAL PASSAGE TOWARD THE WEEKEND. DAYS ARE ALSO FORECAST TO BE
HUMID, WITH TEMPERATURES STARTING AROUND NORMAL BUT RISING TO ABOVE
NORMAL FOR MUCH OF THE WEEK. IF THE REMNANTS OF THE MID LEVEL LOW
PASS US IN TIME ON TUESDAY, THEN THAT MAY BE THE WARMEST DAY OF THE
LONG TERM. WE PRESENTLY ARE FORECASTING DRIER AND COOLER AIR FOR THE
END OF THE PERIOD.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR WILL GRADUALLY LOWER TO MVFR AND ULTIMATELY POORER CONDITIONS
AS WE GO THROUGH THE OVERNIGHT. THE PERSISTENT ONSHORE FLOW WILL BRING
DEEPER MOISTURE WITH SOME SHOWERS TONIGHT INTO SUNDAY. WE HAVE
SPED UP THE TIMING OF THE LOWER CONDITIONS BY A FEW HOURS WHEN
COMPARED TO THE PREVIOUS TAFS. MODEL GUIDANCE SHOWING THE
DETERIORATING CIGS/VSBYS, SO CONFIDENCE IN THEM OCCURRING IS
GOOD, BUT THE TIMING IS STILL SOMEWHAT UNCERTAIN. LOOKS LIKE THE
LOW CIGS/VSBYS WILL CARRY ON INTO SUNDAY, SO WE DID NOT REALLY INDICATE
MUCH IMPROVEMENT AFTER 12Z ANYWHERE. WINDS SHOULD REMAIN MOSTLY
ERLY/SERLY AT 5 TO 10 KTS IN MOST AREAS.
OUTLOOK...
SUNDAY NIGHT...MAINLY MVFR CEILINGS WITH POSSIBLE IFR CONDITIONS AT
TIMES. A CHANCE OF SHOWERS. CONFIDENCE IS MODERATE.
MONDAY THROUGH THURSDAY...MAINLY VFR CONDITIONS FROM LATE MORNING
THROUGH THE EVENING. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE VISIBILITY,
AND THEY ARE SOMEWHAT MORE LIKELY IN THE AFTERNOON AND EVENING.
ALSO, MVFR AND IFR CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE
LATE NIGHT AND EARLY MORNING HOURS. CONFIDENCE IS MODERATE.
&&
.MARINE...
THE ONSHORE FLOW BETWEEN THE HIGH WELL OFF TO THE NORTHEAST AND THE
APPROACHING FRONT TO THE WEST WILL CAUSE WINDS (AND THEN SEAS) TO
SLOWLY INCREASE TONIGHT INTO SUNDAY. IT APPEARS THAT SEAS WILL REACH
SCA CRITERIA (5 FT) ACROSS THE SRN WATERS FIRST (TONIGHT) AND THEN
ACROSS THE NRN COASTAL WATERS SUNDAY. WE WILL ISSUE SCA FLAGS TO
COVER THIS EXPECTED INCREASE IN SEAS. SCA FLAGS WILL EXTEND THRU
SUNDAY FOR NOW. SPRINKLES THIS EVENING THEN SCATTERED/OCNL SHOWERS
OVERNIGHT AND SUNDAY.
OUTLOOK...
SUSTAINED WINDS ARE FORECAST TO REMAIN BELOW 25 KNOTS THROUGH
WEDNESDAY NIGHT, ALTHOUGH THERE MAY BE SOME OCCASIONS WHEN 25 KNOT
GUSTS OCCUR MAINLY ON MONDAY. WINDS MAY BEGIN TO INCREASE AGAIN ON
THURSDAY. SEAS ON OUR OCEAN WATERS ARE FORECAST TO REMAIN AT AROUND
5 FEET THROUGH MONDAY NIGHT. THEY MAY REMAIN THERE LONGER IN THE
SOUTH TO SOUTHWEST FLOW, ALTHOUGH THAT FLOW IS FORECAST TO RELAX SOME
FOR THE MID-WEEK PERIOD.
&&
.RIP CURRENTS...
THERE IS A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP
CURRENTS ALONG THE NEW JERSEY BEACHES SUNDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ453>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...GORSE/KLINE
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/KLINE/O`HARA
MARINE...DELISI/O`HARA
RIP CURRENTS...KLINE/DRAG
000
FXUS61 KPHI 190200
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1000 PM EDT SAT MAY 18 2013
.SYNOPSIS...
A STATIONARY FRONT TO OUR SOUTHWEST IS FORECAST TO SLOWLY DISSIPATE
THROUGH MONDAY. HIGH PRESSURE TO OUR NORTHEAST WILL DROP SOUTH AND
TAKE ON THE CHARACTERISTICS OF A BERMUDA HIGH. A FRONTAL BOUNDARY
FROM THE NORTH WILL APPROACH OUR AREA ON TUESDAY AND STALL NEARBY.
THE FRONT MAY LIFT BACK NORTH LATER IN THE WEEK. A COLD FRONT
APPROACHING FROM THE WEST MAY CROSS OUR AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
WITH THE LATE EVENING UPDATE, WE INCREASED POPS FROM SOUTHERN DE
TO CENTRAL NJ TO REFLECT THE STEADIER, SCATTERED SHOWERS
CURRENTLY PASSING THROUGH THESE AREAS. WAA IS TAKING SHAPE ACROSS
THE FORECAST AREA, AND THERE LOOKS TO BE A DEVELOPING CONVERGENCE
ZONE INTO CENTRAL PORTIONS OF NJ. QPF AMOUNTS WERE ALSO RAISED
SOME, AS A FEW HUNDREDTHS TO A TENTH OF AN INCH OF RAIN ARE
EXPECTED FOR THESE AREAS IN THE NEXT FEW HOURS. SLIGHT CHANCE POPS
WERE LEFT IN PLACE ACROSS NORTHERN NJ AND THE SOUTHERN POCONOS FOR
THE NEXT FEW HOURS. PRECIP COVERAGE THROUGH THE LATE EVENING HOURS
AND INTO THE OVERNIGHT WAS ADJUSTED TO REFLECT SCATTERED SHOWERS,
AND THE TIMING OF INCREASING POPS FROM SOUTH TO NORTH DURING THE
OVERNIGHT LOOKS REASONABLE. WE ALSO ADJUSTED HOURLY TEMPERATURES
AND DEWPOINTS TO REFLECT CURRENT TRENDS USING LAV/LAMP GUIDANCE.
OTHERWISE, HIGH PRESSURE TO THE NORTH/EAST AND AN APPROACHING
WARM FRONT TO THE WEST WILL CREATE DETERIORATING WEATHER
CONDITIONS ACROSS THE AREA TONIGHT. THE GFS MODEL BRING SHOWERS TO
THE EXTREME NORTH EARLY TONIGHT THEN LIGHT SHOWERS TO ALL AREAS
AFTER MIDNIGHT. THE NAM IS MORE ROBUST WITH THE QPF AND BRINGS IT TO
MOST AREAS BY MIDNIGHT AND MAKES IT LAST INTO SUNDAY. WE HAVE
FOLLOWED A BLENDED APPROACH WITH LOW LIKELY POPS TO MOST AREAS
TONIGHT. THE ONSHORE FLOW WILL KEEP CONDITIONS MILD...SO THE LOWS
WILL MOSTLY BE IN THE UPPER 50S/LOW 60S SOUTH AND LOW TO MID 50S
NORTH. WINDS WILL CONTINUE FROM THE E/SE AT AROUND 10 MPH.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE FRONT WILL BE SLOW TO CROSS THE AREA. A WEAK UPPER LOW WILL ALSO
BE INTERACTING WITH THE FRONT...SO ANOTHER DAY OF ABUNDANT
CLOUDINESS AND SCATTERED SHOWERS IS EXPECTED. WE WILL KEEP THE LOW
LIKELY POPS ACROSS THE AREA EARLY...THEN LOWER THEN AFTER THAT. THIS
IS MORE LIKE THE NAM STAT GUIDANCE...BUT CONFID IN THE AMOUNT/QPF
FOR SUNDAY IS RATHER LOW ATTM. HIGH TEMPERATURES WILL MOSTLY BE IN
THE MID TO UPPER 60S FAR NORTH...LOW 70S CENTRAL AREAS AND PERHAPS
INTO THE MID OR UPPER 70S FAR SOUTH...ESPECIALLY IF ANY BREAKS
DEVELOP IN THE CLOUDS LATE. QPF FCST...MOSTLY 1/10 TO 1/4 INCH WITH
THE HIGHER TOTALS ACROSS THE DELMARVA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
THE MID LEVELS STILL START WITH A VORTEX OVER EASTERN CANADA, A
RIDGE BUILDING FROM THE WESTERN ATLANTIC AND A LOW CROSSING THE
ROCKIES. THERE ALSO ARE THE REMAINS OF THE LOW THAT CAUSED THE SPLIT
FLOW EARLIER THIS WEEK, AND THEY ARE FORECAST TO MOVE SLOWLY TOWARD
AND THEN ACROSS OUR AREA INTO TUESDAY. IT LOOKS THOSE REMAINS AND
THE VORTEX TO THE NORTH WILL COMBINE TO KEEP THE RIDGE FROM BUILDING
TOO MUCH UP THE EASTERN SEABOARD THROUGH THE FIRST PART OF THE LONG
TERM, AND THEN THE LOW APPROACHING FROM THE WEST WILL BEGIN TO PUSH
THE RIDGE TO THE EAST. THAT LOW IS EXPECTED TO OPEN DURING THE
MID-WEEK PERIOD AND EVENTUALLY CROSS OUR LONGITUDE. WHETHER IS DOES
SO BEFORE THE END OF THE LONG TERM IS UP IN THE AIR. THE GFS KEEPS
SOMETHING OF A REX BLOCK OVER THE CENTER OF THE NATION GOING INTO
THURSDAY, AND IS THEREFORE NOT AS PROGRESSIVE AS THE ECMWF. THE 12Z
GEFS SUPPORT THE OPERATIONAL GFS, AND THE 00Z ECMWF ENSEMBLES
SUPPORT THE OPERATIONAL 00Z AND 12Z ECMWF. WE THEREFORE HAVE SIDED
WITH THE FORECAST FROM HPC, WHICH LEANS TOWARD THE LATTER SUITE AND
MAINTAINS DECENT CONTINUITY.
THE MODELS AGREE ON GRADUALLY MOVING THE CENTER OF SURFACE HIGH
PRESSURE FROM NORTH OF 40N TO SOUTH OF IT, AND THAT TRANSITIONS US
FROM A MARITIME FLOW WITH AN EASTERLY COMPONENT TO A MORE SOUTHERLY
AND HUMID FLOW AND A MORE (ESPECIALLY AWAY FROM THE OCEAN) UNSTABLE
FLOW. THE VORTEX TO THE NORTH STILL TRIES TO PUSH A COLD FRONT DOWN
INTO OUR AREA AROUND TUESDAY NIGHT, AND IT MAY STALL NEARBY. ALL THIS
WILL SEND US FROM A PERIOD OF SHOWERS TO A PERIOD WHEN THUNDERSTORMS
ARE POSSIBLE. AT THIS POINT, WE REALLY CAN`T CARVE OUT A TIME PERIOD
WHEN WE AREN`T CARRYING A CHANCE OF THUNDERSTORMS UNTIL THE SYSTEM
FROM THE WEST MOVES THROUGH WITH A SURFACE COLD FRONT. SINCE WE HAVE
SIDED WITH THE MORE PROGRESSIVE SOLUTION, OUR POPS DO DROP BELOW
CHANCE BY SATURDAY. AS NOTED BY THE PREVIOUS LONG TERM FORECASTER,
THUNDERSTORM ACTIVITY WILL NOT BE CONSTANT. IN THE ABSENCE OF ANY
FOCUSED ENERGY KICKING OUT OF THE SYSTEM TO THE WEST, ACTIVITY WOULD
BE MOST LIKELY DURING THE AFTERNOON AND EVENING HOURS.
NIGHTS ARE FORECAST TO BE WARMER THAN NORMAL AND RATHER HUMID UNTIL
THE FRONTAL PASSAGE TOWARD THE WEEKEND. DAYS ARE ALSO FORECAST TO BE
HUMID, WITH TEMPERATURES STARTING AROUND NORMAL BUT RISING TO ABOVE
NORMAL FOR MUCH OF THE WEEK. IF THE REMNANTS OF THE MID LEVEL LOW
PASS US IN TIME ON TUESDAY, THEN THAT MAY BE THE WARMEST DAY OF THE
LONG TERM. WE PRESENTLY ARE FORECASTING DRIER AND COOLER AIR FOR THE
END OF THE PERIOD.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS WILL GRADUALLY BE LOWERING TO MVFR AND ULTIMATELY
POORER CONDITIONS AS WE GO THROUGH THE NEXT SEVERAL HOURS. THE
PERSISTENT ONSHORE FLOW WILL BRING DEEPER MOISTURE THIS EVENING
AND THEN OCCASIONAL SHOWERS TONIGHT INTO SUNDAY. WE HAVE SPED UP
THE TIMING OF THE LOWER CONDITIONS BY A FEW HOURS WHEN COMPARED TO
THE PREVIOUS TAFS. BOTH THE GFS AND NAM ARE SHOWING THE
DETERIORATING CIGS/VSBYS...SO CONFID IN THEM OCCURRING IS
GOOD...BUT THE TIMING IS STILL SOMEWHAT UNCERTAIN. LOOKS LIKE THE
LOW CIGS/VSBYS WILL CARRY ON INTO SUNDAY...SO I FAILED TO WRITE IN
ANY IMPROVEMENT AFTER 12Z ANYWHERE. WINDS SHOULD REMAIN MOSTLY
ERLY/SERLY AT 5 TO 10 KTS IN MOST AREAS.
OUTLOOK...
SUNDAY NIGHT...MAINLY MVFR CEILINGS WITH POSSIBLE IFR CONDITIONS AT
TIMES. A CHANCE OF SHOWERS. CONFIDENCE IS MODERATE.
MONDAY THROUGH THURSDAY...MAINLY VFR CONDITIONS FROM LATE MORNING
THROUGH THE EVENING. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE VISIBILITY,
AND THEY ARE SOMEWHAT MORE LIKELY IN THE AFTERNOON AND EVENING.
ALSO, MVFR AND IFR CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE
LATE NIGHT AND EARLY MORNING HOURS. CONFIDENCE IS MODERATE.
&&
.MARINE...
THE ONSHORE FLOW BETWEEN THE HIGH WELL OFF TO THE NORTHEAST AND THE
APPROACHING FRONT TO THE WEST WILL CAUSE WINDS (AND THEN SEAS) TO
SLOWLY INCREASE TONIGHT INTO SUNDAY. IT APPEARS THAT SEAS WILL REACH
SCA CRITERIA (5 FT) ACROSS THE SRN WATERS FIRST (TONIGHT) AND THEN
ACROSS THE NRN COASTAL WATERS SUNDAY. WE WILL ISSUE SCA FLAGS TO
COVER THIS EXPECTED INCREASE IN SEAS. SCA FLAGS WILL EXTEND THRU
SUNDAY FOR NOW. SPRINKLES THIS EVENING THEN SCATTERED/OCNL SHOWERS
OVERNIGHT AND SUNDAY.
OUTLOOK...
SUSTAINED WINDS ARE FORECAST TO REMAIN BELOW 25 KNOTS THROUGH
WEDNESDAY NIGHT, ALTHOUGH THERE MAY BE SOME OCCASIONS WHEN 25 KNOT
GUSTS OCCUR MAINLY ON MONDAY. WINDS MAY BEGIN TO INCREASE AGAIN ON
THURSDAY. SEAS ON OUR OCEAN WATERS ARE FORECAST TO REMAIN AT AROUND
5 FEET THROUGH MONDAY NIGHT. THEY MAY REMAIN THERE LONGER IN THE
SOUTH TO SOUTHWEST FLOW, ALTHOUGH THAT FLOW IS FORECAST TO RELAX SOME
FOR THE MID-WEEK PERIOD.
&&
.RIP CURRENTS...
THERE IS A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP
CURRENTS ALONG THE NEW JERSEY BEACHES SUNDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ453>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA/KLINE
MARINE...DELISI/O`HARA
RIP CURRENTS...KLINE/DRAG
000
FXUS61 KPHI 182151
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
551 PM EDT SAT MAY 18 2013
.SYNOPSIS...
A STATIONARY FRONT TO OUR SOUTHWEST IS FORECAST TO SLOWLY DISSIPATE
THROUGH MONDAY. HIGH PRESSURE TO OUR NORTHEAST WILL DROP SOUTH AND
TAKE ON THE CHARACTERISTICS OF A BERMUDA HIGH. A FRONTAL BOUNDARY
FROM THE NORTH WILL APPROACH OUR AREA ON TUESDAY AND STALL NEARBY.
THE FRONT MAY LIFT BACK NORTH LATER IN THE WEEK. A COLD FRONT
APPROACHING FROM THE WEST MAY CROSS OUR AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
WITH THE EARLY EVENING UPDATE, WE INCREASED POPS FROM EAST-CENTRAL
PA INTO CENTRAL NJ TO REFLECT THE STEADIER, SCATTERED SHOWERS
CURRENTLY PASSING THROUGH THESE AREAS. QPF AMOUNTS WERE ALSO
RAISED SOME, AS A FEW HUNDREDTHS OF AN INCH OF RAIN ARE EXPECTED
FOR THESE AREAS. SLIGHT CHANCE POPS WERE LEFT IN PLACE FOR THE
SOUTHERN POCONOS AND NORTHERN NJ, AND THESE AREAS WILL LIKELY HAVE
A BREAK IN MEASURABLE PRECIP FOR THE NEXT FEW HOURS. PRECIP
COVERAGE THROUGH THE LATE EVENING HOURS WAS ADJUSTED TO REFLECT
SCATTERED SHOWERS, AND THE TIMING OF INCREASING POPS FROM SOUTH TO
NORTH LATER TONIGHT LOOKS REASONABLE AS COMPARED TO THE HRRR,
WHICH WAS REFLECTING CURRENT RADAR TRENDS FAIRLY WELL. WE ALSO
ADJUSTED HOURLY TEMPERATURES AND DEWPOINTS THROUGH THIS EVENING
ACCORDINGLY TO REFLECT CURRENT TRENDS, INCLUDING WHERE SHOWERS
HAD PASSED THROUGH.
OTHERWISE, HIGH PRESSURE TO THE NORTH/EAST AND AN APPROACHING
WARM FRONT TO THE WEST WILL CREATE DETERIORATING WEATHER
CONDITIONS ACROSS THE AREA TONIGHT. THE GFS MODEL BRING SHOWERS TO
THE EXTREME NORTH EARLY TONIGHT THEN LIGHT SHOWERS TO ALL AREAS
AFTER MIDNIGHT. THE NAM IS MORE ROBUST WITH THE QPF AND BRINGS IT TO
MOST AREAS BY MIDNIGHT AND MAKES IT LAST INTO SUNDAY. WE HAVE
FOLLOWED A BLENDED APPROACH WITH LOW LIKELY POPS TO MOST AREAS
TONIGHT. THE ONSHORE FLOW WILL KEEP CONDITIONS MILD...SO THE LOWS
WILL MOSTLY BE IN THE UPPER 50S/LOW 60S SOUTH AND LOW TO MID 50S
NORTH. WINDS WILL CONTINUE FROM THE E/SE AT AROUND 10 MPH.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE FRONT WILL BE SLOW TO CROSS THE AREA. A WEAK UPPER LOW WILL ALSO
BE INTERACTING WITH THE FRONT...SO ANOTHER DAY OF ABUNDANT
CLOUDINESS AND SCATTERED SHOWERS IS EXPECTED. WE WILL KEEP THE LOW
LIKELY POPS ACROSS THE AREA EARLY...THEN LOWER THEN AFTER THAT. THIS
IS MORE LIKE THE NAM STAT GUIDANCE...BUT CONFID IN THE AMOUNT/QPF
FOR SUNDAY IS RATHER LOW ATTM. HIGH TEMPERATURES WILL MOSTLY BE IN
THE MID TO UPPER 60S FAR NORTH...LOW 70S CENTRAL AREAS AND PERHAPS
INTO THE MID OR UPPER 70S FAR SOUTH...ESPECIALLY IF ANY BREAKS
DEVELOP IN THE CLOUDS LATE. QPF FCST...MOSTLY 1/10 TO 1/4 INCH WITH
THE HIGHER TOTALS ACROSS THE DELMARVA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
THE MID LEVELS STILL START WITH A VORTEX OVER EASTERN CANADA, A
RIDGE BUILDING FROM THE WESTERN ATLANTIC AND A LOW CROSSING THE
ROCKIES. THERE ALSO ARE THE REMAINS OF THE LOW THAT CAUSED THE SPLIT
FLOW EARLIER THIS WEEK, AND THEY ARE FORECAST TO MOVE SLOWLY TOWARD
AND THEN ACROSS OUR AREA INTO TUESDAY. IT LOOKS THOSE REMAINS AND
THE VORTEX TO THE NORTH WILL COMBINE TO KEEP THE RIDGE FROM BUILDING
TOO MUCH UP THE EASTERN SEABOARD THROUGH THE FIRST PART OF THE LONG
TERM, AND THEN THE LOW APPROACHING FROM THE WEST WILL BEGIN TO PUSH
THE RIDGE TO THE EAST. THAT LOW IS EXPECTED TO OPEN DURING THE
MID-WEEK PERIOD AND EVENTUALLY CROSS OUR LONGITUDE. WHETHER IS DOES
SO BEFORE THE END OF THE LONG TERM IS UP IN THE AIR. THE GFS KEEPS
SOMETHING OF A REX BLOCK OVER THE CENTER OF THE NATION GOING INTO
THURSDAY, AND IS THEREFORE NOT AS PROGRESSIVE AS THE ECMWF. THE 12Z
GEFS SUPPORT THE OPERATIONAL GFS, AND THE 00Z ECMWF ENSEMBLES
SUPPORT THE OPERATIONAL 00Z AND 12Z ECMWF. WE THEREFORE HAVE SIDED
WITH THE FORECAST FROM HPC, WHICH LEANS TOWARD THE LATTER SUITE AND
MAINTAINS DECENT CONTINUITY.
THE MODELS AGREE ON GRADUALLY MOVING THE CENTER OF SURFACE HIGH
PRESSURE FROM NORTH OF 40N TO SOUTH OF IT, AND THAT TRANSITIONS US
FROM A MARITIME FLOW WITH AN EASTERLY COMPONENT TO A MORE SOUTHERLY
AND HUMID FLOW AND A MORE (ESPECIALLY AWAY FROM THE OCEAN) UNSTABLE
FLOW. THE VORTEX TO THE NORTH STILL TRIES TO PUSH A COLD FRONT DOWN
INTO OUR AREA AROUND TUESDAY NIGHT, AND IT MAY STALL NEARBY. ALL THIS
WILL SEND US FROM A PERIOD OF SHOWERS TO A PERIOD WHEN THUNDERSTORMS
ARE POSSIBLE. AT THIS POINT, WE REALLY CAN`T CARVE OUT A TIME PERIOD
WHEN WE AREN`T CARRYING A CHANCE OF THUNDERSTORMS UNTIL THE SYSTEM
FROM THE WEST MOVES THROUGH WITH A SURFACE COLD FRONT. SINCE WE HAVE
SIDED WITH THE MORE PROGRESSIVE SOLUTION, OUR POPS DO DROP BELOW
CHANCE BY SATURDAY. AS NOTED BY THE PREVIOUS LONG TERM FORECASTER,
THUNDERSTORM ACTIVITY WILL NOT BE CONSTANT. IN THE ABSENCE OF ANY
FOCUSED ENERGY KICKING OUT OF THE SYSTEM TO THE WEST, ACTIVITY WOULD
BE MOST LIKELY DURING THE AFTERNOON AND EVENING HOURS.
NIGHTS ARE FORECAST TO BE WARMER THAN NORMAL AND RATHER HUMID UNTIL
THE FRONTAL PASSAGE TOWARD THE WEEKEND. DAYS ARE ALSO FORECAST TO BE
HUMID, WITH TEMPERATURES STARTING AROUND NORMAL BUT RISING TO ABOVE
NORMAL FOR MUCH OF THE WEEK. IF THE REMNANTS OF THE MID LEVEL LOW
PASS US IN TIME ON TUESDAY, THEN THAT MAY BE THE WARMEST DAY OF THE
LONG TERM. WE PRESENTLY ARE FORECASTING DRIER AND COOLER AIR FOR THE
END OF THE PERIOD.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A WEALTH OF MID LEVEL CLOUDS ARE ACROSS THE TERMINALS AT LATE DAY
WITH MOSTLY LIGHT WINDS. THESE VFR CONDITIONS WILL PROBABLY
CONTINUE INTO THE EARLY EVENING BEFORE POORER CONDITIONS ARRIVE.
THE PERSISTENT ONSHORE FLOW WILL BRING DEEPER MOISTURE THIS
EVENING AND THEN OCCASIONAL SHOWERS TONIGHT INTO SUNDAY. WE HAVE
SPED UP THE TIMING OF THE LOWER CONDITIONS BY A FEW HOURS WHEN
COMPARED TO THE PREVIOUS TAFS. BOTH THE GFS AND NAM ARE SHOWING
THE DETERIORATING CIGS/VSBYS...SO CONFID IN THEM OCCURRING IS
GOOD...BUT THE TIMING IS STILL SOMEWHAT UNCERTAIN. LOOKS LIKE THE
LOW CIGS/VSBYS WILL CARRY ON INTO SUNDAY...SO I FAILED TO WRITE IN
ANY IMPROVEMENT AFTER 12Z ANYWHERE. WINDS SHOULD REMAIN MOSTLY
ERLY/SERLY AT 5 TO 10 KTS IN MOST AREAS.
OUTLOOK...
SUNDAY NIGHT...MAINLY MVFR CEILINGS WITH POSSIBLE IFR CONDITIONS AT
TIMES. A CHANCE OF SHOWERS. CONFIDENCE IS MODERATE.
MONDAY THROUGH THURSDAY...MAINLY VFR CONDITIONS FROM LATE MORNING
THROUGH THE EVENING. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE VISIBILITY,
AND THEY ARE SOMEWHAT MORE LIKELY IN THE AFTERNOON AND EVENING.
ALSO, MVFR AND IFR CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE
LATE NIGHT AND EARLY MORNING HOURS. CONFIDENCE IS MODERATE.
&&
.MARINE...
THE ONSHORE FLOW BETWEEN THE HIGH WELL OFF TO THE NORTHEAST AND THE
APPROACHING FRONT TO THE WEST WILL CAUSE WINDS (AND THEN SEAS) TO
SLOWLY INCREASE TONIGHT INTO SUNDAY. IT APPEARS THAT SEAS WILL REACH
SCA CRITERIA (5 FT) ACROSS THE SRN WATERS FIRST (TONIGHT) AND THEN
ACROSS THE NRN COASTAL WATERS SUNDAY. WE WILL ISSUE SCA FLAGS TO
COVER THIS EXPECTED INCREASE IN SEAS. SCA FLAGS WILL EXTEND THRU
SUNDAY FOR NOW. SPRINKLES THIS EVENING THEN SCATTERED/OCNL SHOWERS
OVERNIGHT AND SUNDAY.
OUTLOOK...
SUSTAINED WINDS ARE FORECAST TO REMAIN BELOW 25 KNOTS THROUGH
WEDNESDAY NIGHT, ALTHOUGH THERE MAY BE SOME OCCASIONS WHEN 25 KNOT
GUSTS OCCUR MAINLY ON MONDAY. WINDS MAY BEGIN TO INCREASE AGAIN ON
THURSDAY. SEAS ON OUR OCEAN WATERS ARE FORECAST TO REMAIN AT AROUND
5 FEET THROUGH MONDAY NIGHT. THEY MAY REMAIN THERE LONGER IN THE
SOUTH TO SOUTHWEST FLOW, ALTHOUGH THAT FLOW IS FORECAST TO RELAX SOME
FOR THE MID-WEEK PERIOD.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 AM EDT
MONDAY FOR ANZ453>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
|
