AFDOKX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NEW YORK NY
412 AM EDT MON JUN 27 2011

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH MONDAY NIGHT. A
WARM FRONT WILL LIFT NORTH ACROSS THE AREA TUESDAY. A COLD FRONT
WILL CROSS THE TRI-STATE TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE
BUILDING IN FROM THE GREAT LAKES THROUGH FRIDAY...THAT THEN SLIDES
OFFSHORE FRIDAY NIGHT. A WARM FRONT LIFTS TO OUR NORTH
SATURDAY...WITH HIGH PRESSURE BUILDING IN TO OUR SOUTHEAST THROUGH
THE UPCOMING WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
STLT INDICATES SKC...OUTSIDE OF SOME LATE NIGHT STRATUS AND
FOG...ACROSS UPSTATE NY AND WRN PA W OF THE H5 TROF AXIS. THIS
AIRMASS WILL BUILD OVER THE CWA TODAY ALLOWING FOR MOSTLY SUNNY
SKIES. TEMPS WERE A BLEND OF MAV/MET AND ARE RIGHT AROUND NORMAL
FOR THIS TIME OF YEAR. A SEA BREEZE CAN BE EXPECTED ALONG THE
COASTS THIS AFTN. 00Z NAM INDICATES SOME -SHRA ALONG THE BOUNDARY
IN CT THIS AFTN. WITH THE BOUNDARY ENDING UP JUST N OF THE CWA AND
SYNOPTIC SUBSIDENCE...FCST WILL BE KEPT DRY.

SE SWELL CONTINUES TODAY. ALTHOUGH WIND COMPONENT IS NOT
STRONG...RIP OBS WERE MDT-STRONG YESTERDAY. BECAUSE OF THE SIMILAR
SWELL TODAY...WILL INDICATE A MDT THREAT FOR RIPS IN THE SRF FCST.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
MAIN FCST CONCERN FOR TONIGHT WILL BE THE AMOUNT OF HIGH CLOUDS
THAT OVERSPREAD THE CWA FROM MIDWEST CONVECTION. CLOUDS ARE
CURRENTLY OUTRUNNING THE MODEL DATA SLIGHTLY...SO IF THIS TREND
CONTINUES...AN INCREASE IN THE CLOUD FCST CAN BE EXPECTED. THE
RESULT WOULD BE A SLIGHTLY LOWER POTENTIAL FOR SHALLOW FOG INTO
TUE MRNG ACROSS THE OUTLYING AREAS. FOR NOW...FOG IS INCLUDED IN
THE FCST WITH CALM WINDS AND NO MID/LOW CLOUDS EXPECTED.

WARM FRONT CURRENTLY OVER THE VA/NC BORDER WILL LIFT N ON TUE. THE
FRONT LOOKS TO PASS BY LATE AFTN. MEANWHILE...H5 TROF RACING
ACROSS CANADA WILL APPROACH FROM THE W. ATTM...TIMING IS NOT IN
PHASE WITH THE LATE AFTN PRIME TIME FOR CONVECTION. ALTHOUGH TSTMS
ARE INCLUDED IN THE FCST FOR THE AFTN...THE THREAT WILL BE
ENHANCED IF THE FEATURE ARRIVES A FEW HOURS FASTER THAN CURRENTLY
PROGGED BY THE NAM/GFS...AND CLOSER TO THE 00Z ECMWF.

INCREASED HEIGHTS WILL LEAD TO WARMER TEMPS THAN TODAY ACROSS THE
INTERIOR...WHILE ONSHORE FLOW WILL MEAN SLIGHTLY LOWER TEMPS THAN
TODAY FOR SOME SPOTS ALONG THE IMMEDIATE COASTS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE GFS IS THE SLOWEST OF THE MODELS WITH THE COLD FRONT TUESDAY
NIGHT AND HAS BEEN DISCARDED AS A SLOW OUTLIER. HAVE MAINTAINED
LIKELY POPS TUESDAY NIGHT...THOUGH WITH INSTABILITY LIMITED TO ALOFT
HAVE RESTRICTED THE PROBABILITY OF THUNDERSTORMS TO CHANCE. THERE
ARE SOME SIGNS THE FRONT COULD BECOME ANAFRONTAL IN NATURE...SO DO
HAVE SOME POPS IN FOR SHOWERS THE FIRST PART OF WEDNESDAY MORNING
- SLIGHT CHANCE TO CHANCE TAPERING OFF FROM W TO E. THE 00Z ECMWF
IS ALONE IN BRINGING THE 500 HPA LOW AS FAR S/E AS IT DOES DURING
THE DAY ON WED - AND WITH IT AN ASSOCIATED CHANCE OF INSTABILITY
SHRA/TSRA - SO HAVE OPTED NOT TO INCLUDE THIS IN THE FORECAST FOR
NOW.

FOR LOWS TUESDAY NIGHT USED A 2/3 MAV/MET BLEND WITH 1/3 NAM 2-METER
TEMPERATURES...AND FOR HIGHS WEDNESDAY BLENDED A MAV/MET BLEND WITH
A MIXING DOWN FROM 825 HPA - PER BUFKIT SOUNDINGS. THE RESULT IS
TEMPERATURES A FEW DEGREES ABOVE NORMAL.

FOR THE WEDNESDAY NIGHT-THURSDAY NIGHT PERIOD FAVORED THE CMC-GLOBAL
AS IT IS IN BETWEEN THE DEEPER/SLOWER 500 HPA LOW IN THE ECMWF AND
THE MORE OPEN/PROGRESSIVE LOW IN THE GFS. WITH 20-30KT OF
DOWN SLOPING LOW LEVEL BOUNDARY LAYER FLOW WORKING TO HELP DRY OUT
THE LOWER LEVELS OF THE ATMOSPHERE...DO NOT FEEL THERE WILL BE
ENOUGH MOISTURE AVAILABLE FOR ANY SHORTWAVES ROTATING AROUND THE
BASE OF THE UPPER LEVEL LOW TO TRIGGER ANY SHRA/TSRA...SO WENT WITH
A DRY FORECAST.

ECMWF AND GFS ARE IN GOOD AGREEMENT THAT 500 HPA RIDGING BUILDS IN
FRIDAY-SATURDAY - THE QUESTION IS HOW FAR EAST DOES ITS CORE
GET...THE GFS IS MORE BULLISH THAN THE ECMWF. SO FOR NOW TOOK TO
BLENDING THEIR LOW LEVEL MASS AND THERMAL FIELDS. INTRODUCE SLIGHT
CHANCE POPS LATE FRIDAY NIGHT AND SATURDAY TO REFLECT APPROACHING
WARM FRONT THAT LIFTS TO THE N SATURDAY.

THE GFS AND ECMWF DIFFER SATURDAY NIGHT-SUNDAY ON HOW FAR S A
NORTHERN STREAM SHORTWAVE GETS. THE GFS MOVES IT TO THE EAST NEAR
THE US/CANADIAN BORDER...WHILE THE ECMWF HAS IT FURTHER N. FOR NOW
LEANING MORE TOWARDS THE ECMWF WITH THIS FEATURE...LEAVING THE
REGION UNDER THE INFLUENCE OF WEAK TROUGHING AT THE SURFACE AND ON
THE NE PERIPHERY OF THE UPPER RIDGE ALOFT. GIVEN THE FAVORABLE
LOCATION ON THE /RING OF FIRE/ AND THE PRESENCE OF THE SURFACE
TROUGH...HAVE GONE WITH SLIGHT CHANCE POPS FOR DIURNAL SHRA/TSRA.

FOR TEMPERATURES WEDNESDAY NIGHT-SUNDAY USED A MEX/MEX ENSEMBLE MEAN
BLEND...ADJUSTED TOWARDS CMC-GLOBAL LOW LEVEL THERMAL FIELDS
WEDNESDAY NIGHT-THURSDAY NIGHT AND A BLEND OF ECMWF/GFS LOW LEVEL
THERMAL FIELDS FRIDAY-SUNDAY. EXPECT TEMPERATURES TO START OUT
SLIGHTLY BELOW NORMAL WEDNESDAY NIGHT/THURSDAY...THEN GRADUALLY WARM
TO ABOVE NORMAL BY FRIDAY NIGHT...AND CONTINUE ABOVE NORMAL THROUGH
THE WEEKEND.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BUILD INTO THE AREA TODAY. A WARM FRONT WILL
APPROACH FROM THE SW TONIGHT.

OUTSIDE OF SOME PATCHY MVFR FOG AT OUTLYING TERMINALS
(KISP/KHPN/KSWF) TOWARDS MORNING...VFR THROUGH 06Z TUE. MID AND
HIGH CLOUDS WILL SHIFT SE OF LI WITH SKC DEVELOPING. LIGHT WINDS
(NW BECOMING N) THROUGH THE MORNING WITH SEABREEZE DEVELOPMENT AT
THE COAST LATE THIS MORNING/EARLY AFTN. TIMED FOR 15Z AT CT
TERMINALS AND BETWEEN 16Z AND 18Z AT NYC/LI TERMINALS. EXPECT
SOUND BREEZE TO DEVELOP AT KLGA THIS MORNING...TIMING MAY BE OFF A
FEW HOURS.

OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...

MON NIGHT-TUE MORNING...PATCHY MVFR FOG POSSIBLE...OTHERWISE VFR.

TUE AFTN/NIGHT...POSSIBLE SUB-VFR IN SHRA/TSRA.

WED-FRI...CHANCE SUB-VFR EARLY AM WED...OTHERWISE VFR.

&&

.MARINE...
LIGHT FLOW THRU TUE WILL RESULT IN WINDS/SEAS BLW SCA LVLS. THE
STRONGEST WINDS TODAY WILL BE NEARSHORE DUE TO SEA BREEZE FLOW.
WINDS WILL VEER TO THE S BEHIND THE WARM FRONT TUE.

SUB-SMALL CRAFT CONDITIONS ARE EXPECTED TUESDAY NIGHT-FRIDAY.
OUTSIDE OF SOME STRONGER WINDS WEDNESDAY NIGHT AS 15-20 KT WINDS MIX
DOWN FROM 950 HPA...WINDS SHOULD BE 10 KT OR LESS THROUGH THE PERIOD
DUE TO A RELAXED PRESSURE GRADIENT OVER THE REGION.

&&

.HYDROLOGY...
UP TO AROUND A HALF AN INCH OF BASIN AVERAGE RAINFALL IS POSSIBLE
AHEAD OF A FRONTAL SYSTEM TUESDAY AFTERNOON AND NIGHT...WITH
LOCALLY HIGHER AMOUNTS POSSIBLE IN ANY STRONGER CONVECTION.

DRY CONDITIONS ARE THEN EXPECTED WEDNESDAY-FRIDAY.

&&

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

&&

$$