National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS61 KOKX 222035
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
435 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/...
WEAK FRONTAL BOUNDARY REMAINS STALLED JUST TO THE W AND S OF THE
AREA...WITH A MARINE AIRMASS REMAINING IN PLACE. THIS FRONT SHOULD
NOT MOVE MUCH...IF AT ALL TONIGHT...SO WOULD EXPECT MOST IF NOT
ALL PRECIPITATION TO GO N OF THE AREA. THIS IS CONSISTENT WITH THE
HRRR AND RAP...WHICH HAVE HAD THE BEST HANDLE ON THIS FRONT AND
THE WEATHER TODAY BY FAR...ALONG WITH THE NAM AND SREF.

BASED ON THIS HAVE GONE BASICALLY DRY ACROSS THE S 2/3 OF THE CWA
THIS EVENING...WITH SLIGHT CHANCE POPS FAR N TIER...THEN SLIGHT
CHANCE POPS THROUGHOUT OVERNIGHT IN RESPONSE TO AN APPROACHING
700-500 HPA SHORTWAVE.

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 /21Z WEDNESDAY THROUGH MONDAY/...
FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON.
AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND
VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE
IMPROVEMENT PRIMARILY AT NW TERMINALS.

IFR CONDITIONS MAY BE A LITTLE SLOWER TO RETURN AT KEWR...KTEB...AND
KSWF OVERNIGHT. HOWEVER...STILL HIGH ENOUGH POTENTIAL THAT IFR
CONDITIONS WERE INCLUDED IN THESE TAFS IN ADDITION TO ALL OTHER
SITES OVERNIGHT. POTENTIAL EXISTS FOR COASTAL TERMINALS TO DROP TO
LIFR AS WELL.

LOW-END CHANCES FOR TS TO AFFECT ANY ONE TERMINAL SITE AFTER 18Z
THURSDAY. HOWEVER...DID INCLUDE PROB30 GROUPS AT 30-HOUR SITES TO
INDICATE THE GROWING POTENTIAL LATE IN THE DAY.

     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: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.

KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY EARLY
THIS EVENING.

KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS.

KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS.

KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.

KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.

.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY
THUR NIGHT AND FRIDAY. IFR POSSIBLE IN 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 G
UP TO 40KT.
.MONDAY...VFR. NW WINDS 15-20G25KT.

&&

.MARINE...
LATEST SATELLITE IMAGERY...WEB-CAMS...AND RAP SOUNDINGS WARRANT
EXTENDING DENSE FOG ADVISORY FOR THE WATERS S/W OF LONG ISLAND
THROUGH TONIGHT. MIGHT ULTIMATELY END UP NEED TO EXTEND INTO
THURSDAY MORNING - BUT TO MUCH UNCERTAINTY WITH TIMING OF MIXING
AHEAD OF APPROACHING SHORTWAVE LATE TONIGHT TO DO SO AT THIS TIME.

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 ANZ338-345-350-
     353-355.
     SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ350-353-355.

&&

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