Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 140926
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
426 AM EST SUN FEB 14 2016

.SYNOPSIS...

HIGH PRESSURE BUILDS OVER THE AREA ON TODAY AND OFFSHORE TONIGHT.
THE HIGH CONTINUES TO MOVE EAST AWAY INTO THE ATLANTIC MONDAY AS A
LOW PRESSURE SYSTEM DEVELOPS TO THE WEST. THIS LOW TRAVELS NEAR OR
TO THE WEST OF THE REGION TUESDAY AND INTO THE CANADIAN MARITIMES
TUESDAY NIGHT. A CLIPPER LOW MOVES IN FOR WEDNESDAY INTO WEDNESDAY
NIGHT. THEN...CANADIAN HIGH PRESSURE RETURNS FOR THURSDAY AND
FRIDAY. FOR FRIDAY NIGHT INTO SATURDAY NEXT WEEK...ANOTHER LOW
APPROACHES FROM THE NORTH AND WEST.

&&

.NEAR TERM /THROUGH TONIGHT/...

POLAR LOW SLIDES EAST ON NEW ENGLAND THIS MORNING...WITH MODERATING
ARCTIC HIGH PRESSURE BUILDING IN FROM THE WEST TODAY INTO TONIGHT.

COLDEST AIR AS OF 4 AM IS SITTING ACROSS CONNECTICUT THIS MORNING
WITH LOWS GENERALLY 5 TO 10 DEGREES BELOW ZERO...AND WIND CHILLS
AROUND 20 TO 30 DEGREES BELOW ZERO. THIS IS COINCIDENT WITH THE AXIS
OF THE -30C 850 HPA CORE. 1 BELOW ZERO AT NWS NEW YORK ON
BROOKHAVEN LABS AS OF 3AM...AND 3 DEGREES AT CENTRAL PARK. TEMPS
SHOULD DROP ANOTHER 2 TO 3 DEGREES BY DAYBREAK.

TODAY WILL BE SUNNY...FRIGID...AND DRY WITH NW FLOW ALOFT AND ARCTIC
HIGH PRESSURE BUILDING IN. AFTER A DANGEROUSLY COLD START TO THE
DAY...DIMINISHING WINDS AND A MODERATING AIRMASS SHOULD ALLOW TEMPS
TO MODERATE INTO THE TEENS...WITH WIND CHILLS FINALLY RISING ABOVE
ZERO BY LATE DAY/EARLY EVE. WIND CHILL W/A WILL BE ALLOWED TO EXPIRE
AT NOON WITH DECREASING WINDS MODERATING APPARENT TEMPS ABOVE -15
DEGREES.

HIGH PRESSURE MOVES ACROSS TONIGHT...WITH STRONG RADIATIONAL COOLING
CONDS LIKELY FOR THE FIRST HALF OF THE NIGHT...BEFORE HIGH CLOUDS
BEGIN TO MOVE IN. THIS SHOULD ALLOW FOR TEMPS TO FALL TO 5 TO
POSSIBLY 10 BELOW ZERO ACROSS RURAL EASTERN LOCALES LIKE THE PINE
BARRENS OF LI AND INTERIOR VALLEYS OF CT WHERE A SOLID SNOWPACK
EXISTS. 0 TO 5 BELOW ZERO ACROSS INTERIOR VALLEYS OF LOWER HUDSON
VALLEY. ELSEWHERE TEMPS WILL LIKELY BOTTOM OUT IN THE SINGLE DIGITS
ALONG THE COASTAL PLAIN...WHILE HOLDING STEADY IN THE MID TEENS FOR
NYC METRO. TEMPS THEN COULD RISE LATE TONIGHT AND TOWARDS DAYBREAK
WITH INCREASING HIGH CLOUDS.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
MODELS IN GENERAL AGREEMENT WITH SEVERAL PIECES OF PAC ENERGY
HELPING TO AMPLIFY A CENTRAL US TROUGH TODAY INTO MONDAY...WHICH
SLIDES INTO THE OHIO/TENNESSEE VALLEYS MONDAY NIGHT...AND THEN
SWINGS UP THE COAST ON TUESDAY. DETERMINISTIC MODELS AND ENSEMBLES
STILL EXHIBITING SOME MODEL SPREAD AND JUMPINESS ON TIMING AND
AMPLITUDE OF THIS SHORTWAVE ENERGY AS IT COMES UP THE COAST. SBU
SENSITIVITY TRACKING THIS MODEL SPREAD TO THE PAC ENERGY COMING
ONSHORE THIS MORNING.

THIS MODEL SPREAD IN SHORTWAVE EVOLUTION IS STILL MANIFESTING
DIFFERENCES IN TIMING AND TRACK OF LOW PRESSURE. 00Z GFS/UKMET/CAN
AND 00Z GEFS/03Z SREF ARE CLUSTERED ON A TRACK OF LOW PRESSURE FROM
THE DEEP SOUTH MONDAY MORNING...TO TENNESSEE RIVER VALLEY MONDAY
NIGHT AND THEN AN INLAND TRACK UP INTO CENTRAL PA/NY ON TUESDAY.
NAM/ECMWF TRACKS LOW PRESSURE RIGHT ALONG THE COAST AND SLIGHTLY
SLOWER. THIS IS A SIGNIFICANT EASTWARD SHIFT FOR THE ECMWF FROM 12-
24 HRS AGO AND WESTWARD SHIFT FOR THE GFS. AGAIN...NOT INSTILLING
CONFIDENCE.

12Z GEFS/21ZSREF/12Z CMC ENSEMBLE MEANS WERE PRETTY WELL CLUSTERED
WITH A MEAN LOW TRACK ALONG THE EAST SIDE OF THE APPALACHIANS ON
TUESDAY. MUCH OF THE SPREAD WAS ON THE W/SW SIDE OF THE LOW...WHICH
MAY SIGNAL A FURTHER WEST TRACK SIMILAR TO THE DETERMINISTIC
CLUSTERING AND PERHAPS A BIT SLOWER. THIS HAS BORNE OUT WITH THE 00Z
SREF AND GEFS ENSEMBLE MEANS FURTHER WEST. BASED ON THIS...WILL LEAN
TOWARDS THE BETTER CLUSTERED LOW TRACK NEAR THE APPALACHIANS.

IN TERMS OF SENSIBLE WEATHER...A LIKELY SCENARIO AT THIS POINT
CONTINUES TO BE LIGHT SNOW DEVELOPMENT MONDAY MORN/AFT FROM SW TO
NE FOR THE ENTIRE AREA WITH WARM ADVECTION IN DEEP SW FLOW ALOFT OVER
THE MODERATING ARCTIC AIRMASS. AS WAA INCREASES...EXPECTATION FOR
PRECIP TO CHANGE TO WINTRY MIX AND THEN LIQUID MONDAY EVENING FROM S
TO N. ALONG THE CITY/COAST...TRANSITION FROM SNOW TO RAIN SHOULD BE
FAIRLY QUICK IN THE EVENING WITH STRENGTHENING ONSHORE FLOW.
GENERALLY AN INCH OR TWO OF SNOW ALONG THE COAST...BUT POTENTIAL
FOR ROAD ICING EXISTS A COUPLE OF HOURS AFTER TRANSITION TO RAIN
AS AIR TEMPS MAY WARM ABOVE FREEZING QUICKER THAN GROUNDS TEMPS.
INCREASING POTENTIAL FOR ICING AWAY FROM SOUTH COASTS. ACROSS
INTERIOR PORTIONS OF NE NJ...LOWER HUDSON VALLEY...AND SW
CT...A GENERAL 2 TO 4 INCHES OF SNOW POSSIBLE THROUGH MON EVENING
AND THEN SEVERAL HOURS OF FREEZING RAIN POSSIBLE MONDAY NIGHT
BEFORE LOW LEVEL WAA FINALLY SCOUR LOW- LEVEL COLD AIR MASS BY
EARLY TUESDAY MORNING. WITH PRECEDING ARCTIC AIRMASS...GROUND
TEMP WARM UP WILL LIKELY LAG AIR TEMP WARMUP...WHICH COULD RESULT
IN SERIOUS ROAD ICING ISSUES. WILL ADDRESS THREAT IN HWO.

ON TUESDAY...RAIN...POSSIBLY HEAVY AT TIMES...WITH TEMPERATURES WELL
INTO THE 40S TO 50S AS WARM CONVEYOR BELT OVERRIDES THE REGION IF
INLAND TRACK VERIFIES. A GENERAL RANGE OF 1 TO 2 1/2 INCHES OF TOTAL
QPF IS FORECAST IN THE CONSENSUS OF THE MODELS. SEE HYDRO SECTION
FOR MORE INFORMATION.

CONSENSUS LOW TRACK WOULD ALSO RESULT IN WINDY CONDITIONS ALONG THE
COAST WITH 60 TO 65 KT JET AT 950 HPA MOVING OVER THE REGION. WINDS
OF 25 TO 30 MPH WITH GUSTS TO 40 MPH WOULD BE LIKELY...WITH
POTENTIAL FOR WIND ADVISORY CONDITIONS OF SUSTAINED WINDS IN THE
LOWER 30S AND GUSTS TO 50 MPH.

LLJ/DEEP MOISTURE AXIS MOVES EAST TUESDAY EVENING WITH DRYING CONDS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...

FOR THE REST OF THE FORECAST TUESDAY NIGHT AND WEDNESDAY...LINGERING
RAIN AND SNOW SHOWERS POSSIBLE AS MAIN LOW MOVES INTO THE CANADIAN
MARITIMES AND ANOTHER SHORTWAVE MOVES THROUGH ALOFT WITH ITS PVA.
DRIER CONDITIONS WILL BECOME MORE PREVALENT WEDNESDAY NIGHT
ALTHOUGH THERE COULD BE A FEW SNOW SHOWERS REMAINING WEDNESDAY
NIGHT. ANOTHER ROUND OF COLD AIR ADVECTION OCCURS WEDNESDAY NIGHT
BEHIND THE SHORTWAVE. STRONG CANADIAN HIGH PRESSURE MOVES IN
THURSDAY THROUGH EARLY FRIDAY WITH DRY WEATHER. ANOTHER LOW AND
ANOTHER CHANCE OF PRECIPITATION ARRIVES FRIDAY INTO SATURDAY OF
NEXT WEEK.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...

NO SIGNIFICANT CHANGES MADE TO PREVIOUS TAF PACKAGE. ARCTIC HIGH
PRES CONTINUES TO BUILD INTO THE REGION THROUGH THIS EVENING.

VFR THROUGH THE TAF PERIOD.

GUSTY NW WINDS WILL CONTINUE TO DIMINISH INTO THIS AFTERNOON. NW
WINDS 15-20 KT WITH 20-30 KT GUSTS WILL DIMINISH TO 10-15 KT WITH
GUSTS UP TO 20 KT BY 18Z. GUSTS SHOULD END AT ALL BUT KNYC TERMINALS
BY THEN. WINDS WILL DIMINISH TO LESS THAN 10 KT BY LATE
AFTERNOON/EARLY EVENING. WIND DIRECTION WILL BE MAINLY AT OR JUST
RIGHT OF 310 MAGNETIC.

.OUTLOOK FOR 09Z MONDAY THROUGH THURSDAY...
.SUNDAY NIGHT...VFR. LIGHT WINDS.
.MONDAY...LIGHT SNOW LIKELY DEVELOPS FROM W TO E LATE
MORNING/INTO THE AFTERNOON...WITH MVFR OR LOWER POSSIBLE. S WIND
G15-20KT POSSIBLE.
.MONDAY NIGHT...IFR OR LOWER DEVELOPING. A WINTRY MIX CHANGING TO
RAIN AT S TERMINALS...AND SNOW CHANGING TO A WINTRY MIX AT
NORTHERN TERMINALS. LLWS POSSIBLE. LOW CONFIDENCE FORECAST.
.TUESDAY...ANY LINGERING WINTRY MIX N TERMINALS CHANGING TO ALL
RAIN IN THE MORNING. RAIN TAPERING OFF LATE. IFR OR LOWER
POSSIBLE. LLWS IN THE AM...THEN NW WINDS G20-25KT POSSIBLE IN THE
AFTERNOON.
.TUESDAY NIGHT...VFR.
.WEDNESDAY...MOSTLY VFR. MVFR OR LOWER POSSIBLE IN ANY SPOTTY
RAIN/SNOW SHOWER. W-NW WINDS G20-25KT POSSIBLE.
.WEDNESDAY NIGHT-THURSDAY...VFR. NW WINDS G15-20KT POSSIBLE.

&&

.MARINE...

WINDS DIMINISHING ON THE WATERS...BUT GALES WILL CONTINUE ON THE
OCEAN AND E LI SOUND THROUGH 15Z THIS MORNING. ON NY HARBOR/W LI
SOUND/LI BAYS...EXPECTING SMALL CRAFT ADVISORY CONDS THROUGH
AFTERNOON WITH WIND GUSTS TO 25 KT. TRANQUIL CONDS EXPECTED BY THIS
EVENING. FREEZING SPRAY WILL ALSO CONTINUE THROUGH THIS MORNING.

SUB SCA CONDITIONS MONDAY WILL BE FOLLOWED BY SCA TO GALE CONDITIONS
MONDAY NIGHT INTO TUESDAY. GALES TREND TO SCA WINDS LATER TUESDAY
AND TUESDAY NIGHT. THE WINDS TREND BELOW SCA THEREAFTER BUT SCA
OCEAN SEAS REMAIN.

&&

.HYDROLOGY...

A GENERAL 1 TO 2 1/2 INCHES OF LIQUID EQUIVALENT IS FORECAST WITH
LOCALLY HIGHER AMOUNTS MONDAY THROUGH TUESDAY NIGHT. THIS WILL BE
MOSTLY BE IN THE FORM OF RAIN.

THIS TYPE OF RAINFALL WILL BRING POTENTIAL FOR URBAN AND POOR
DRAINAGE FLOODING. LI AND EASTERN CT ALSO HAVE MORE IN THE WAY OF
SNOWPACK AND SNOW CLOGGED DRAINAGES TO ADD TO POOR DRAINAGE FLOOD
POTENTIAL.

WITH INITIALLY FROZEN GROUND...SIGNIFICANT RISES ARE LIKELY WITH
POTENTIAL MINOR FLOODING ALONG FLASHY SMALL STREAMS ACROSS NE
NJ/LOWER HUDSON VALLEY IF HIGH END OF RAINFALL AMOUNTS ARE
REALIZED. MMEFS AND STEVENS FAS ARE NOT SHOWING ANY AREAS GOING
INTO FLOOD AS OF YET.

&&

.TIDES/COASTAL FLOODING...
POTENTIAL EXISTS FOR MINOR COASTAL FLOOD IMPACTS WITH THE LATE
MONDAY NIGHT/EARLY TUESDAY MORNING AND POSSIBLY TUE AFT HIGH TIDE
CYCLES AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM MOVING UP THE
COASTAL PLAIN. STILL QUITE A BIT OF UNCERTAINTY EXISTS ON THE
TIMING AND TRACK OF THIS SYSTEM. POSITIVE TIDAL DEPARTURES OF 2 TO
2 1/2 FT ARE NEEDED FOR MINOR FLOOD THRESHOLDS TO BE REACHED IN
THE MORNING...AND 2 1/2 TO 3 FT IN THE AFTERNOON.

&&

.CLIMATE...
WITH THE EXTREMELY COLD AIR MASS...RECORD MINIMUMS AND RECORD LOW
MAXIMUMS MAY BE REACHED. HERE ARE THE RECORDS AND FORECASTS...

STATION......RECORD LOW(YEAR)/FCST LOW BY MIDNIGHT FOR 2/13


LAGUARDIA.........8 (2016)  /  8
ISLIP.............4 (2016)  /  4

STATION......RECORD LOW(YEAR)/4AM TEMP FOR 2/14

CENTRAL PARK.....2 (1916)  /  3
LAGUARDIA........1 (1979)  /  5
KENNEDY..........4 (1979)  /  5
ISLIP............7 (2015)  /  3
NEWARK...........0 (1979)  /  5
BRIDGEPORT.......3 (2015*) / -4

STATION......RECORD LOW MAXIMUM(YEAR)/FCST HIGH FOR 2/14

CENTRAL PARK....17 (1979) / 15
LAGUARDIA.......15 (1979) / 16
KENNEDY.........17 (1979) / 17
ISLIP...........26 (1987) / 13
NEWARK..........15 (1979) / 15
BRIDGEPORT......18 (1979) / 13

*IN 1979 AS WELL

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WIND CHILL WARNING UNTIL NOON EST TODAY FOR CTZ005>012.
NY...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR NYZ072>075-
     078>081-176>179.
     WIND CHILL WARNING UNTIL NOON EST TODAY FOR NYZ067>071.
NJ...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR NJZ004-006-
     103>108.
     WIND CHILL WARNING UNTIL NOON EST TODAY FOR NJZ002.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ335-
     338-340-345.
     HEAVY FREEZING SPRAY WARNING UNTIL NOON EST TODAY FOR ANZ330-
     335-340.
     HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST EARLY THIS MORNING
     FOR ANZ338.
     GALE WARNING UNTIL 10 AM EST THIS MORNING FOR ANZ330-350-353-
     355.
     FREEZING SPRAY ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350-
     353-355.

&&

$$
SYNOPSIS...NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...JM
AVIATION...MPS
MARINE...MPS
HYDROLOGY...NV
TIDES/COASTAL FLOODING...NV
CLIMATE...NV


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