000
FXUS61 KOKX 222351
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
751 PM EDT WED MAY 22 2013

.SYNOPSIS...
A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN MOVE
INTO WESTERN PORTIONS OF THE TRI-STATE THURSDAY NIGHT. A WAVE OF
LOW PRESSURE DEVELOPS ALONG THIS SLOW MOVING COLD FRONT
FRIDAY...REMAINS JUST EAST OF THE REGION SATURDAY...AND THEN
TRACKS NORTH ALONG THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE
OVER THE GREAT LAKES BUILDS SOUTHEAST ACROSS THE AREA MONDAY INTO
TUESDAY. A WARM FRONT WILL THEN APPROACH FROM THE SOUTHWEST BY MID
WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
MOST OF THE SHOWERS AND THUNDERSTORMS NORTH OF THE CWA ARE
BEGINNING TO DISSIPATE WITH LOSS OF DIURNAL HEATING. WOULD NOT
EXPECT MUSH IN THE WAY OF CONVECTIVE ACTIVITY...MAINLY FOR THE
NORTHERN THIRD OF THE CWA...FOR THE REST OF THE EARLY EVENING
HOURS. 

HOWEVER...BROKEN LINE OF SHOWERS AND THUNDERSTORMS SLOWLY TRYING
TO ORGANIZE OVER CENTRAL PA. WITH RELATIVELY LIGHT UPPER LEVEL
FLOW...THESE STORMS WILL TAKE SOME TIME APPROACHING WESTERN
PORTIONS OF THE CWA...AND IF THEY DO MAKE IT HERE...IT WILL NOT BE
UNTIL LATE TONIGHT WITH LATEST HRRR INDICATING SCT ACTIVITY AFTER
08Z. WILL CONTINUE TO CARRY SLIGHT CHANCE...AS MARINE LAYER SHOULD
CONTINUE TO INHIBIT CONVECTIVE ACTIVITY FROM FORMING.

WITH MARINE LAYER INTACT - WOULD EXPECT LOW CLOUD DECK TO RE-
ESTABLISH ITSELF ACROSS THE AREA OVERNIGHT. COULD SEE PATCHY FOG
AS WELL - POSSIBLY LOCALLY DENSE NEAR THE ATLANTIC COAST.

FOR LOWS USED A BLEND OF 50 PERCENT MAV GUIDANCE WITH 25 PERCENT
MET GUIDANCE AND 25 PERCENT NAM 2-METER TEMPERATURES. FORECASTING
LOWS 10-15 DEGREES ABOVE NORMAL.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MIXING ASSOCIATED WITH PASSING 700-500 HPA SHORTWAVE THURSDAY
MORNING SHOULD ERODE THE MARINE INVERSION - BUT STILL WILL BE
LEFT WITH QUITE A BIT OF MID TO HIGH CLOUDS WITH MOIST SW FLOW
ALOFT.

PRE-FRONTAL TROUGH MOVING INTO THE LOWER HUDSON VALLEY/NE NJ
THURSDAY AFTERNOON SHOULD SERVE AS TRIGGER FOR SCT-NUMEROUS SHRA
WITH EMBEDDED TSRA. LIKELY POPS MAINLY FROM NYC-INTERIOR SW CT
ZONES ON W AND CHANCE POPS EAST OF THAT LINE. SOME SUGGESTION FROM
NAM/GFS THAT EASTERN AREAS WILL REMAIN DRY THURSDAY...BUT FOR NOW
TOO MUCH LOW-MID LEVEL MOISTURE AND INCREASING LOW LEVEL JET TO
FORECAST THAT AT THIS TIME.

WITH 30-35 KT BULK SHEAR...1000-1500 J/KG OF CAPE AND BULK
RICHARDSON NUMBERS 15-30 HAVE THE POTENTIAL FOR ISOLATED SEVERE
STORMS THURSDAY AFTERNOON ACROSS NE NJ/LOWER HUDSON VALLEY AND
MAYBE NYC AND SW CT ZONES. MAIN THREAT IS GUSTY WINDS AND LARGE
HAIL. ALSO NEED TO WATCH FOR LOW LEVEL HELICITY WITH S SFC FLOW
AND SW FLOW AT 850 HPA.

FOR HIGHS THURSDAY USED A BLEND OF MIXING DOWN FROM 975 HPA NEAR
THE COAST AND 950 HPA INLAND...WITH NAM 2-METER TEMPERATURES AND A
BLEND OF MAV AND MET GUIDANCE. FORECASTING VALUES AROUND NORMAL
EAST TO A FEW DEGREES ABOVE NORMAL WEST.

DEEP SW FLOW ALOFT...BECOMES DIFFLUENT AT 500 HPA AFTER MIDNIGHT.
HAVE THE POTENTIAL FOR HEAVY RAINFALL AS A RESULT. REFER TO THE
HYDROLOGY SECTION FOR DETAILS. SEVERE THREAT COULD LINGER INTO THE
EVENING ACROSS WESTERN ZONES AS WELL.

FOR LOWS THURSDAY NIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST AROUND 10 DEGREES ABOVE NORMAL.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MODELS HAVE TRENDED CONSIDERABLY SLOWER AND DEEPER WITH THE 
APPROACHING UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY. THERE 
IS VERY GOOD AGREEMENT WITH THE 12Z GFS AND ECMWF ON TAKING A CLOSED 
UPPER LOW FROM THE MID ATLANTIC STATES ON FRI NE TO OVER NEW ENGLAND 
ON SUN. THE NAM AND GGEM ARE TRENDING IN THAT DIRECTION...BUT ARE 
MORE PROGRESSIVE BEYOND 00Z SAT. PREFERENCE AT THIS TIME IS TO GO 
WITH THE SLOWER GFS/ECMWF SOLUTION BASED ON MODEL TRENDS AND THE RUN 
TO RUN CONTINUITY BEING EXHIBITED OVER THE LAST SEVERAL MODEL CYCLES.

AS FOR SENSIBLE WEATHER...THIS RESULTS IN A WET...COOL WEEKEND WITH 
THE POTENTIAL FOR ANOTHER 1 TO 2 INCHES OF RAINFALL IN THE FRI-SAT 
TIME FRAME. SINCE THIS IS A BIG ADJUSTMENT FROM THE PREVIOUS 
FORECAST...HAVE RAMPED UP RAIN CHANCES FRI INTO SAT...BUT THESE MAY 
BE UNDERDONE...ESPECIALLY FOR SAT WHERE THERE IS A TREND IN THE 
FORECAST TO DRY THINGS OUT SAT INTO SUN. LATEST ECMWF KEEPS  
CONDITIONS WET INTO SUN WITH A GUSTY NW FLOW ON THE BACKSIDE. SO 
THIS IS THE POINT IN THE FORECAST WHERE CONDITIONS MAY CONTINUE TO 
DETERIORATE WITH SUBSEQUENT MODEL RUNS.

ONCE AGAIN...WHILE THE FORECAST HAS AGGRESSIVELY TAKEN A DOWNWARD 
NOTE FOR THE HOLIDAY WEEKEND...RAIN CHANCES MAY BE ON THE INCREASE 
SAT INTO SUN BASED ON LATEST TRENDS IN THE MODEL GUIDANCE.

IN ADDITION...SOME OF THE RAINFALL ON FRI...OR AT LEAST THE FIRST 
HALF OF THE DAY MAY BE CONVECTIVE WITH LOCALIZED HEAVY RAINFALL WITH 
ANY EMBEDDED THUNDERSTORMS. THEREAFTER...THE AIRMASS STABILIZES IN 
THE LOW-LEVELS WITH POST-FRONTAL RAIN/SHOWERS...PRIMARILY DRIVEN BY 
FRONTOGENETIC FORCING ON THE BACKSIDE OF THE LOW. WIND GUSTS SAT 
INTO SUN MAY BE UP TO 35 MPH...BUT THIS IS THE POTENTIAL...WITH THE 
FORECASTS SIGNIFICANTLY LOWER AT THIS TIME.

AS FOR TEMPS...DAYTIME HIGHS WITH THE CLOUD COVER AND RAIN WILL BE 5 
TO 10 DEGREES BELOW NORMAL. STAYED BELOW GUIDANCE. OVERNIGHT LOWS 
WILL BE CLOSE TO SEASONABLE. A GRADUAL WARM-UP TO NEAR SEASONABLE 
LEVELS IS THEN FORECAST MON-WED.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A STATIONARY FRONTAL BOUNDARY WILL REMAIN NORTH OF THE TERMINALS 
THROUGH THE FORECAST PERIOD. A LOW PRESSURE SYSTEM AND COLD FRONT 
APPROACH SLOWLY FROM THE WEST DURING THE DAY THURSDAY.

MVFR CEILINGS AND FOG DEVELOP LATE THIS EVENING AND OVERNIGHT FOR 
THE NEW YORK CITY TERMINALS AND WEST. TO THE EAST IFR CEILINGS AND 
FOG WILL BE DEVELOPING...WITH LIFR AT TIMES AFTER 07Z. MVFR 
CONDITIONS DURING THURSDAY WITH SHOWERS DEVELOPING AFTER 17Z. 
ISOLATED THUNDERSTORMS WILL BE POSSIBLE ALSO.

WIND WILL BE GENERALLY FROM THE SOUTH 10 KT OR LESS THROUGH LATE 
TONIGHT...THEN SOUTH TO SOUTHWEST 10 TO 15 KT LATE TONIGHT INTO 
THURSDAY.


     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)

KJFK FCSTER COMMENTS: AMENDMENTS LATE THIS EVENING FOR MVFR 
CEILINGS AND FOG DEVELOPING. AMENDMENTS FOR TIMING OF SHOWERS AND 
THUNDERSTORMS THURSDAY. SOME THUNDERSTORMS MAY PRODUCE GUSTY 
WINDS.

KLGA FCSTER COMMENTS: AMENDMENTS LATE THIS EVENING FOR MVFR 
CEILINGS AND FOG DEVELOPING. AMENDMENTS FOR TIMING OF SHOWERS AND 
THUNDERSTORMS THURSDAY. SOME THUNDERSTORMS MAY PRODUCE GUSTY WINDS. 

KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS TONIGHT. AMENDMENTS 
FOR TIMING OF SHOWERS AND THUNDERSTORMS THURSDAY. SOME THUNDERSTORMS 
MAY PRODUCE GUSTY WINDS.

KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS TONIGHT. MVFR 
CEILINGS AND FOG POSSIBLE AFTER 09Z. AMENDMENTS FOR TIMING OF 
SHOWERS AND THUNDERSTORMS THURSDAY. SOME THUNDERSTORMS MAY PRODUCE 
GUSTY WINDS.

KHPN FCSTER COMMENTS: AMENDMENTS LATE THIS EVENING FOR MVFR 
CEILINGS AND FOG DEVELOPING...WITH IFR AT TIMES.  AMENDMENTS FOR 
TIMING OF SHOWERS AND THUNDERSTORMS THURSDAY. SOME THUNDERSTORMS MAY 
PRODUCE GUSTY WINDS.  

KISP FCSTER COMMENTS: AMENDMENTS THIS EVENING FOR IFR CEILINGS AND 
FOG. AMENDMENTS THURSDAY FOR SLOWLY IMPROVING CONDITIONS. SHOWERS 
LATE AFTERNOON THURSDAY.

.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.THURSDAY NIGHT-FRIDAY...NUMEROUS SHRA...ISOLATED TSTMS POSSIBLE. 
MVFR TO IFR IN SHOWERS...FOG AND STRATUS.
.SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT.
.SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR GUSTS 
UP TO 40KT.
.MONDAY...VFR. NW WINDS 15-20G25KT.

&&

.MARINE...
WENT AHEAD AND EXPANDED THE DENSE FOG ADVISORY TO INCLUDE ALL
WATERS AS WEB-CAMS NEAR LI SOUND...MAINLY EASTERN LI SOUND...
INDICATED LOWERING VSBY. SO FAR...DENSE FOG ADVISORY WILL EXPIRE
AT 6 AM THURSDAY...BUT THIS MAY HAVE TO BE EXTENDED THROUGH THE
MID-MORNING HOURS.

SEAS ARE RUNNING 1-2 FT BELOW WAVEWATCH FORECAST - SO FOR NOW HAVE
TAKEN 1 FT OFF OF WAVEWATCH THROUGH THURSDAY NIGHT. STILL EXPECT
SEAS TO COME UP TO SCA LEVELS TONIGHT AND CONTINUE THROUGH
THURSDAY NIGHT. WINDS ALSO INCREASE LATE TONIGHT AND REMAIN UP
INTO THURSDAY NIGHT. INCREASING LOW LEVEL JET THROUGH THURSDAY
NIGHT INCREASES POTENTIAL FOR SCA LEVEL GUSTS OVER THE COASTAL
OCEAN WATERS - SO HAVE KEPT HEADLINE AS SCA VICE CONVERTING TO AN
SCA FOR HAZARDOUS SEAS.

MARINE INVERSION APPEARS WILL LIMIT MIXING - SO WHILE COULD SEE
OCCASIONAL GUSTS TO 25 KT OVER THE REMAINDER OF THE WATERS FROM
LATE TONIGHT INTO THURSDAY NIGHT - DO NOT HAVE CONFIDENCE TO ISSUE
SCA AT THIS TIME FOR THE NON-OCEAN ZONES.

THERE IS A GOOD POTENTIAL FOR SCA CONDITIONS TO CONTINUE THROUGH THE 
UPCOMING WEEKEND AS LOW PRESSURE FORMS OVER THE WATERS ON FRI AND 
LIFTS SLOWLY TO THE NORTH AND EAST. SCA CONDITIONS ARE BECOMING 
INCREASINGLY LIKELY...WITH THE POTENTIAL FOR GALE CONDITIONS SAT 
INTO SUN. WINDS AND SEAS BEGIN TO SUBSIDE LATE SUN INTO MON WITH 
HIGH PRESSURE BUILDING IN FROM THE GREAT LAKES REGION.

&&

.HYDROLOGY...
THERE IS THE POTENTIAL FOR AROUND 3/4 TO 1 INCH BASIN AVERAGE QPF
THURSDAY AND THURSDAY NIGHT WITH LOCALLY HIGHER AMOUNTS. 

DO NOT EXPECT ANY WIDESPREAD FLOOD THREAT THURSDAY FROM ANY
SHRA/TSRA BUT COULD SEE SOME MINOR FLOODING UNDER ANY STRONGER
CONVECTION - ESPECIALLY IF THERE IS ANY TRAINING. 

THE HEAVIEST RAINFALL IN THIS TIME FRAME WILL BE LATE THURSDAY
NIGHT - WITH LOCALIZED RAINFALL RATES OF 1-1.5 INCHES/HR POSSIBLE
NOTING PRECIPITABLE WATERS OF 1.5-1/75 INCHES IN THIS TIME
FRAME. IF THESE RATES ARE REALIZED...ESPECIALLY IF THE STORMS
PRODUCING THEM PASS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL
THURSDAY...THERE IS THE POTENTIAL FOR LOCALIZED FLASH FLOODING.
 
THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL CONTINUE INTO THE FIRST 
HALF OF FRI WITH EMBEDDED CONVECTION. THEREAFTER...A STRATIFORM RAIN 
AND/OR SHOWERS DEVELOPS ON THE BACKSIDE OF DEVELOPING LOW PRESSURE. 
AN ADDITIONAL 1 TO 2 INCHES OF RAINFALL IS POSSIBLE FRI INTO SAT. 
THIS MAY EXACERBATE ANY ONGOING FLOODING. RAIN MAY LINGER EVEN INTO 
SUN BASED ON LATEST MODEL TRENDS. 

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED 
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE 
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ330-335-338-
     340-345-350-353-355.
     SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ350-353-355.

&&

$$
SYNOPSIS...MALOIT/DW
NEAR TERM...MALOIT/MPS
SHORT TERM...MALOIT
LONG TERM...DW
AVIATION...MET
MARINE...MALOIT/DW
HYDROLOGY...MALOIT/DW