-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 171321
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
921 AM EDT FRI MAY 17 2013

.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY...THEN MOVES EAST SATURDAY. A WAVE
OF LOW PRESSURE ALONG A STATIONARY FRONT ACROSS THE MID ATLANTIC
STATES BEGINS TO RETURN NORTHWARD SUNDAY INTO MONDAY. THE FRONT
THEN REMAINS IN CLOSE PROXIMITY TO THE AREA THROUGH MID WEEK UNTIL
A COLD FRONTAL PASSAGE OCCURS LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
FORECAST ON TRACK THIS MORING. THE TROUGH TO THE NORTHEAST WILL SLOWLY
DEPARTS AS A RIDGE REMAINS TO THE WEST OF THE AREA TODAY. WEAK
TROUGH/VORT MAX NEAR TN/KY IN THE MORNING EMBEDDED WITHIN RIDGE
MAKES SLOW PROGRESS EAST.

OTHER THAN HIGH CLOUDS SPILLING OVER THE RIDGE PER VARIOUS MODEL
SOLUTIONS...A GOOD DEAL OF SUNSHINE IS ANTICIPATED THROUGH THE DAY
TODAY.

SHOULD SEE THE DEVELOPMENT OF A WEAK SFC TROUGH BISECTING THE AREA
BETWEEN HIGH PRESSURE TO THE NORTH AND ANOTHER HIGH TO THE SOUTH.

WINDS THIS MORNING WILL REMAIN FROM THE NORTH BEHIND THE EARLIER
FRONTAL PASSAGE. WIND FCST THIS AFTERNOON IS A CHALLENGE AS THE
BATTLE BETWEEN NORTHERLY FLOW AND LOCAL SEA BREEZE COMMENCES. WITH
THE TROUGH NEARBY...WINDS WILL LIKELY SHIFT TO THE WEST/SW OVER A
FEW LOCATIONS ANYWAY...SO WILL ASSUME SEA BREEZES DO INDEED
DEVELOP ACROSS PORTIONS OF THE AREA AS TEMPS WARM.

TIMING WILL BE DIFFICULT. AS SUCH...TEMPS MAY BE OFF BY A FEW
DEGREES. WILL SPLIT THE DIFFERENCE BETWEEN THE MOS...BUT FEEL A LEAN
TOWARD COOLER MET NUMBERS MAY BE WARRANTED WHERE APPROPRIATE.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WEAK TROUGH/VORT MAX TRACKS TO THE SOUTH IN SPLIT FLOW WITH
OVERALL RIDGE BUILDING AND REMAINING TO THE WEST THROUGH THIS TIME
FRAME.

DEEPER MOISTURE IS POSSIBLE BY LATE SATURDAY...WITH THE BEST CHANCE
FOR SHOWERS OR THUNDERSTORMS TO OUR SOUTHWEST CLOSER TO UPPER TROUGH.

OTHERWISE...MAINLY HIGHER LEVEL CLOUDS SPILL OVER THE RIDGE TONIGHT
AND INTO SATURDAY. THERE MAY BE A FEW MORE CLOUDS SATURDAY
AFTERNOON...BUT WILL KEEP THE FCST DRY AT THIS TIME.

TEMPS SHOULD RADIATE TONIGHT AS WINDS LIGHTEN. THIS DEPENDS ON THE
EXTENT OF HIGH CLOUDS THOUGH...BUT MOS SHOWS LARGE MINIMUM TEMP
DIFFERENCES BETWEEN HEAT ISLAND LOCATIONS OF NYC METRO AND THE USUAL
COOLER SPOTS.

50S AND 40S WITH A MOS BLEND FOLLOWED.

ON SATURDAY...ONSHORE FLOW WILL SETUP THE USUAL COOLER TEMPS NEAR
THE COAST...AND WARMER READINGS ACROSS THE INTERIOR AWAY FROM THE
WATER INFLUENCE. TEMPS IN THE 70S...A FEW DEGREES COOLER NEAR THE
SOUTH FACING SHORES.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A MUDDLED FRONTAL BOUNDARY WILL REMAIN IN CLOSE PROXIMITY TO THE
TRI-STATE AREA FOR MUCH OF THIS PERIOD WITH BOUTS OF SHOWERS AND
INCREASINGLY WARM...HUMID CONDITIONS. THERE ARE SOME DISCREPANCIES
AMONGST THE GLOBAL MODELS WITH THE MAGNITUDE OF AN UPPER TROF ACROSS
EASTERN CANADA AS AN UPPER RIDGE OVER THE MS VLY TRANSLATES EAST
THROUGH THE UPCOMING WEEK. BY THE END OF THE WEEK...AN UPPER TROF
EVENTUALLY MOVES ACROSS THE GREAT LAKES AND INTO THE ST LAWRENCE
RIVER VALLEY...PHASING WITH A DEEPENING UPPER LOW OVER EASTERN
CANADA. THE UPPER RIDGE THEN BUILDS OFFSHORE INTO THE WESTERN
ATLANTIC. THE INTERACTION OF ALL THESE FEATURES WILL BE CRITICAL
AS TO WHETHER THE AREA GETS INTO THE WARM SECTOR...OR WHETHER THE
PICTURE IS MORE MUDDLED WITH A FRONTAL BOUNDARY MEANDERING ACROSS
THE REGION FOR MUCH OF THE TIME PERIOD WITH CLOUDS AND CONVECTION.

THE 00Z GFS AND 12Z ECMWF WERE AT ODDS WITH THE FRONTAL BOUNDARY
LOCATION WITH ECMWF KEEPING THE AREA COOLER...AND GENERALLY IN THE
VICINITY OF THE FRONT...WHILE THE GFS KEPT IT NORTH. THE GEFS AND
ECENS SUPPORT THE WARMER SOLUTION. THUS...THE FORECAST HAS
DISCOUNTED THE COLDER 12Z ECMWF. IN FACT...A QUICK GLIMPSE AT THE
00Z ECMWF SUPPORTS A TREND TOWARD THE WARMER SOLUTIONS.

ON SUN...A FRONTAL WAVE TO THE SOUTH ALONG A STATIONARY FRONT WILL
BEGIN TO LIFT SLOWLY NORTHWARD INTO TUE...INCREASING THE CHANCES FOR
SHOWERS. THIS WAVE DAMPENS OUT AS THE FRONT SETTLES JUST NORTH OF
THE REGION. ONCE AGAIN...THIS IS THE TRICKY PART OF THE FORECAST
WHERE THAT BOUNDARY ACTUALLY STALLS. THE FORECAST AREA IS THEN
EXPECTED TO RESIDE IN THE WARM SECTOR TUE-THU WITH CHANCES OF SCT
CONVECTION DURING THE TIME. SHORT WAVES AT THE SOUTHERN EDGE OF THE
WESTERLIES MAY ALSO ALLOW FOR CONVECTIVE COMPLEXES TO FORM AND TRACK
WEST TO EAST ALONG THIS BOUNDARY. THE DETAILS OF SUCH REMAIN TO
UNCERTAIN TO DISCUSSING ANY TIMING AND RAINFALL POTENTIAL.

HIGHS WILL MODERATE INTO THE 70S BY TUE...AND QUITE POSSIBLY THE 80S
INLAND. A SW FLOW FOR MUCH OF THE PERIOD WILL KEEP COASTAL AREAS
COOLER...BUT IT WILL BE MUGGY WITH DEW POINTS APPROACHING 60.
LOWS IN THE 50S WILL CREEP UP TO AROUND 60 DURING THE SAME TIME.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
HIGH CONFIDENCE VFR THROUGH THE TAF PERIOD AS HIGH PRESSURE BUILDS
IN FROM THE GREAT LAKES.

N-NW SFC FLOW WEAKENS THROUGH THE REST OF THE MORNING INTO THE
AFTERNOON ALLOWING FOR COASTAL SEA BREEZES TO FORM DURING THE MID
AFTERNOON.

     NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: WINDS DIMINISH THROUGH THE MORNING AND
GUSTS NOT EXPECTED THIS AFTERNOON. SEA BREEZE COULD REACH EWR
TOWARDS 22Z SHIFTING WIND DIRECTION TO 150.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KJFK FCSTER COMMENTS: MODERATE CONFIDENCE IN SEA BREEZE SHIFTING
WIND DIRECTION PLUS OF MINUS 1 HOUR OF 20Z.

KLGA FCSTER COMMENTS: NORTHEAST (040) SEA BREEZE POSSIBLE AFTER
19Z.

KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KHPN FCSTER COMMENTS: UNSCHEDULED AMENDMENTS NOT SCHEDULED.

KISP FCSTER COMMENTS: SEA BREEZE COULD MOVE THROUGH THE TERMINAL
AFT 20Z.

.OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...
.SATURDAY THROUGH SUNDAY...VFR.
.MONDAY THROUGH TUESDAY...CHANCE OF SUB-VFR CONDS IN SHOWERS.
THUNDERSTORMS POSSIBLE DURING THE DAY.
-- End Changed Discussion --

&&

.MARINE...
HIGH PRESSURE BUILDS BEHIND A COLD FRONT TODAY. NW TO N WINDS BEHIND
THE FRONT WILL PREVAIL THROUGH THE MORNING...WITH PERHAPS LOCAL SEA
BREEZES OCCURRING THIS AFTERNOON. OVERALL WINDS ARE EXPECTED TO
REMAIN RATHER LIGHT UNDER 15 KTS. SEAS OVER THE OCEAN WATERS WILL
CONTINUE TO SUBSIDE PER WAVE WATCH...WHICH CLOSELY MATCHES OBS.

WINDS LIGHTEN FURTHER TONIGHT...THEN THE CENTER OF THE HIGH MOVES
OFFSHORE SATURDAY. WINDS SHIFT AROUND TO THE EAST OR SOUTHEAST BY
SATURDAY...BUT SUB SCA CONDITIONS ARE ANTICIPATED.

ON SUN...A WARM FRONT BEGINS TO APPROACH FROM THE SW. THIS WILL
RESULT IN A STRENGTHENING PRES GRAD ON THE WATERS AND A CHC FOR SCA
E/SE WINDS. ON THE OCEAN...POTENTIAL IS HIGH FOR AT LEAST 5 FT SEAS.
SEAS AOA 5 FT ARE POSSIBLE THRU MID WEEK ON THE OCEAN. ELSEWHERE...
PREVAILING SLY COMPONENT FLOW WILL MAKE IT DIFFICULT TO REACH SCA
LVL WINDS THRU THE PERIOD ATTM.

&&

.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH SATURDAY. ALTHOUGH WIDESPREAD HVY
RAIN EVENTS ARE NOT EXPECTED SUN-THU...THERE WILL BE THE POTENTIAL
FOR TSTMS...ESPECIALLY AFTER MON...WHICH WOULD BE CAPABLE OF
PRODUCING LOC HVY RAINFALL AMOUNTS.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...DW/PW
NEAR TERM...PW
SHORT TERM...PW
LONG TERM...DW
AVIATION...TONGUE
MARINE...DW/PW
HYDROLOGY...DW