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Area Forecast Discussion
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000
FXUS61 KOKX 201955
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
355 PM EDT MON OCT 20 2014

.SYNOPSIS...
LOW PRESSURE MOVES IN FROM THE WEST TONIGHT AND REMAINS IN THE 
VICINITY THROUGH THE MID TO LATE WEEK PERIOD BEFORE MOVING INTO 
THE CANADIAN MARITIME PROVINCES BY SATURDAY MORNING. A COLD FRONT
APPROACHES FROM THE NORTHWEST SATURDAY...THEN CROSSES THE TRI-
STATE SATURDAY NIGHT. HIGH PRESSURE THEN BUILDS INTO THE MID
ATLANTIC STATES EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPPER TROUGH SHIFTS TOWARDS US TONIGHT ALONG WITH A BROAD AREA OF 
LOW PRESSURE AT THE SURFACE. CLOUDS WILL CONTINUE LOWER THROUGH THE 
NIGHT. MODELS AGREE THAT THERE WILL BE SOME ISENTROPIC LIFT AND 
MOISTURE INCREASING OVER THE EASTERNMOST PORTION OF THE TRI STATE 
AREA LATE AT NIGHT BUT WITH SOME DIFFERENCES IN PLACEMENT. THERE 
WILL ALSO BE INCREASING PVA...ESPECIALLY WEST OF THE HUDSON AS THE 
UPPER TROUGH AXIS APPROACHES. WILL CONTINUE WITH OVERALL SLIGHT 
CHANCE TO CHANCE POPS FOCUSED MAINLY AFTER MIDNIGHT TONIGHT...BUT 
WILL GO WITH THE HIGHEST CHANCES FOR THE FAR EASTERN AND FAR WESTERN 
AREAS. 

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
THE SYSTEM SHIFTS EAST DURING TUESDAY...WITH A SURFACE LOW CENTER 
STARTING TO DEVELOP NEAR THE NORTHERN MID-ATLANTIC COAST BY THE END 
OF THE DAY. OVERALL LIFT IS NOT IMPRESSIVE...HOWEVER WITH CONTINUED 
PVA AND STEEPENING LAPSE RATES IN THE MID LEVELS...THINKING IS THAT 
THERE WILL BE AT LEAST SCATTERED SHOWERS AROUND. FOR THE 
AFTERNOON...THERE WILL ALSO BE A SLIGHT CHANCE OF A THUNDERSTORM 
WITH BETTER THE STEEPER LAPSE RATES AND ELEVATED CAPE. 

THE HIGH TEMPERATURE FORECAST IS TRICKY FOR TUESDAY AS EXTENDED 
BREAKS OF PARTLY TO MOSTLY SUNNY CONDITIONS COULD DEVELOP. HAVE GONE 
WITH A MAV/NAM MOS BLEND FOR HIGHS...WHICH WERE SIMILAR.

THE LOW STRENGTHENS TO OUR SOUTH TUESDAY NIGHT...WITH OVERALL BETTER 
LIFT FAVORING THE SOUTHWEST HALF OF THE TRI STATE AREA. HAVE GONE 
WITH LIKELY POPS LATE AT NIGHT HERE...WITH CHC POPS ELSEWHERE. 
ELEVATED CAPE REMAINS WITH ISO TSTMS...GENERALLY SHIFTING EAST AS 
THE NIGHT PROGRESSES.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
CONFIDENCE IS HIGH THAT A CUTOFF LOW WILL TRACK FROM NEAR THE MID 
ATLANTIC COAST WEDNESDAY MORNING TO SOMEWHERE NEAR NOVA SCOTIA BY 
SATURDAY MORNING. AS A RESULT HAVE GONE WITH A MODEL BLEND THROUGH 
THEN.

IT ALSO APPEARS THERE WILL BE SUFFICIENT MID LEVEL INSTABILITY OVER 
THE ENTIRE CWA...AND TO SOME EXTENT LOW LEVEL INSTABILITY MAINLY 
OVER SOUTHERN AND FAR EASTERN ZONES...TO WARRANT A SLIGHT CHANCE OF 
THUNDER WEDNESDAY AND WEDNESDAY NIGHT...IN ADDITION TO LIKELY POPS 
FOR RAIN. APPEARS ALL INGREDIENTS COME TOGETHER ISENTROPICALLY TO 
WARRANT FORECASTING MODERATE RAINFALL FROM WEDNESDAY AFTERNOON 
THROUGH WEDNESDAY NIGHT...WITH THE MODERATE RAINFALL POTENTIAL 
RETREATING TO THE NORTHEAST DURING THE DAY ON THURSDAY. AS THE 
CUTOFF LOW PULLS AWAY THERE WILL BE A CHANCE OF SHOWERS THURSDAY 
NIGHT...TAPERING OFF TO A SLIGHT CHANCE OF SHOWERS BY FRIDAY 
AFTERNOON. FOR NOW IT APPEARS FRIDAY NIGHT SHOULD BE DRY DUE TO 
SUBSIDING NW BOUNDARY LAYER FLOW. REFER TO THE HYDROLOGY SECTION OF 
THE AFD FOR STORM TOTAL QPF AND ANY POTENTIAL IMPACTS.

THE GFS AND ECMWF AGREE ON THE GENERAL FEATURES TO IMPACT THE AREA 
SATURDAY THROUGH MONDAY...BUT DIFFER ON TIMING...AND SOUTHERN PUSH 
OF A SURFACE COLD FRONT SATURDAY NIGHT. NOTING THE GFS SEEMS TO BE 
LIVING UP TO ITS PROGRESSIVE BIAS...AND THE CONSISTENCY OF THE ECMWF 
AND NOTING THAT THE CMC SUPPORTS THE ECMWF...LEANED TOWARDS THE 
ECMWF IN THIS TIME FRAME.

SATURDAY SHOULD BE DRY WITH A SHORTWAVE RIDGE CROSSING THE AREA. 
700-500 HPA TROUGH THEN CROSSES THE AREA SATURDAY NIGHT AND 
SUNDAY...BUT WITH LIMITED LOW LEVEL MOISTURE TO WORK WITH...IT 
SHOULD PASS BY DRY. A DEEP LAYERED RIDGE THEN BUILDS IN THEN BEGINS 
TO BUILD INTO THE REGION INTO MONDAY. 

FOR TEMPERATURES IN THE LONG TERM:

A BLEND OF MAV/MET/ECS GUIDANCE...WITH NAM 2-METER TEMPERATURES AND 
A MIX DOWN FROM 975-950 HPA PER BUFKIT SOUNDINGS WAS USED FOR HIGHS 
ON WEDNESDAY...WITH VALUES FORECAST TO BE AROUND 5 DEGREES BELOW 
NORMAL. FOR LOWS WEDNESDAY NIGHT A BLEND OF MAV/MET GUIDANCE WITH 
NAM 2-METER TEMPERATURES WAS USED - WITH READINGS FORECAST TO BE 
NEAR NORMAL IN NYC AND AROUND 5 DEGREES ABOVE NORMAL ELSEWHERE. FOR 
HIGHS ON THURSDAY A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS 
USED WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 950-925 HPA 
PER BUFKIT SOUNDINGS - WITH VALUES EXPECTED TO BE AROUND 5 DEGREES 
BELOW NORMAL.

FROM THURSDAY NIGHT-MONDAY A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC 
GUIDANCE WAS USED...WITH ECMWF 2-METER TEMPERATURES BLENDED IN 
SUNDAY AND SUNDAY NIGHT...AND THE BLEND ADJUSTED UPWARD 1-2 
CATEGORIES TO COUNTER BIAS TOWARDS CLIMATOLOGY IN THE GUIDANCE THAT 
FAR OUT IN TIME - NOTING FORECAST 850 TEMPERATURES OF AT LEAST 10C 
IN ALL MODELS ON MONDAY. LOWS ARE FORECAST TO RUN ABOVE NORMAL 
THURSDAY NIGHT-SUNDAY NIGHT...WHILE HIGHS ARE FORECAST TO BE ABOVE 
NORMAL...EXCEPT SLIGHTLY BELOW NORMAL ON SUNDAY. HIGHS ON MONDAY 
COULD VERY WELL END UP 5+ DEGREES WARMER THAN FORECAST IF CURRENT 
TRENDS HOLD.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL CONTINUE TO TRACK
EAST INTO THE WESTERN ATLANTIC...WHILE LOW PRESSURE APPROACHES
FROM THE NW.

MAINLY VFR. CHANCE OF -RA LATE TONIGHT...MAINLY KSWF AND EASTERN
TERMINALS. THERE IS A LOW POTENTIAL FOR MVFR CONDITIONS AT KSWF
AND KISP...WITH A BETTER CHANCE BEING AT KGON.

S/SW WINDS AT 10 KT OR LESS THIS AFT...BECOMING LIGHT TONIGHT AND
GRADUALLY BACKING AROUND TO THE SE TUE MORNING.

     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: NO UNSCHEDULED AMENDMENTS EXPECTED.

KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. 

KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. 

KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. 

KISP FCSTER COMMENTS: OCCASIONAL GUSTS TO AROUND 15 KT THIS AFT.

.OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
.TUESDAY AFT-NIGHT...OCNL MVFR CIGS IN LIGHT RAIN. 
.WEDNESDAY THROUGH THURSDAY...MVFR OR LOWER CONDS IN RAIN. NLY
FLOW 10 TO 15 KT G20-25KT.
.FRIDAY...IMPROVING CONDS. NW WINDS 15-20 KT WITH 20-25 KT GUSTS.
.SATURDAY..VFR. NW G20KT.

&&

.MARINE...
SW WINDS EXPECTED TO SUBSIDE TONIGHT WITH A SOMEWHAT WEAKER PRESSURE 
GRADIENT DEVELOPING OVER THE WATERS. WINDS GRADUALLY BACK TOWARDS 
THE EAST BY LATE IN THE DAY TUESDAY...THEN AS A LOW CENTER DEVELOPS 
TO THE SOUTH TUESDAY NIGHT...WINDS BACK FARTHER TOWARDS THE NE AND 
PICK UP AS THE LOW BECOMES STRONGER. WINDS AND SEAS SHOULD HOWEVER 
REMAIN BELOW ADVISORY LEVELS THROUGH THIS PERIOD.

DUE TO UNCERTAINTY IN THE EXACT TRACK AND STRENGTH OF A COASTAL LOW 
WEDNESDAY THROUGH FRIDAY...THERE IS A DEGREE OF UNCERTAINTY IN THE 
FORECAST IN THAT TIME FRAME THAT IS GREATER THAN NORMAL. FOR NOW IT 
APPEARS THERE IS A HIGH CHANCE OF SMALL CRAFT ADVISORY CONDITIONS ON 
THE COASTAL OCEAN WATERS FROM WEDNESDAY THROUGH THURSDAY 
NIGHT...WITH A CHANCE OF SMALL CRAFT CONDITIONS ON THE REMAINDER OF 
THE WATERS DURING THIS TIME FRAME.

SUB-SMALL CRAFT CONDITIONS ARE FORECAST ON ALL WATERS 
FRIDAY-SATURDAY - HOWEVER THERE IS A SMALL CHANCE THAT SMALL CRAFT 
CONDITIONS COULD LINGER INTO FRIDAY ON THE EASTERN WATERS.

&&

.HYDROLOGY...
DRY TODAY...WITH SPOTTY LIGHT RAINFALL AMOUNTS POSSIBLE TONIGHT.

THERE IS THE POTENTIAL FOR AROUND AN INCH OF RAIN FROM TUESDAY
NIGHT INTO THURSDAY NIGHT OVER THE WESTERN 1/3 OF THE
CWA...INCLUDING NYC...AND UP TO 1 1/3 INCHES OF RAIN OVER THE
EASTERN 2/3 OF THE CWA...WITH THE BEST POTENTIAL FOR THE HIGHEST
AMOUNTS OVER EASTERN CT AND LONG ISLAND.

THERE IS THE POTENTIAL FOR LOCALLY HIGHER AMOUNTS IN ANY AREA 
EXPERIENCING STRONGER CONVECTION...WHICH IS LOCALLY POSSIBLE 
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. IF THIS OCCURS...THEN THERE
IS THE POTENTIAL FOR LOCALIZED MINOR URBAN/POOR DRAINAGE
FLOODING. OTHERWISE...WITH THE PRECIPITATION FALLING OVER 48+
HOURS...LITTLE OR NO SIGNIFICANT HYDROLOGIC IMPACT IS EXPECTED.


&&

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

&&

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






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