Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 111809
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
109 PM EST THU FEB 11 2016

.SYNOPSIS...
AN UPR LVL SYS WILL PASS THRU THE REGION THIS AFTERNOON. HIGH
PRES WILL DRIFT ACROSS THE AREA ON FRI. AN ARCTIC COLD FRONT WILL
APPROACH FRI NIGHT...AND PASS THROUGH LATE FRI NIGHT INTO SAT
MORNING WHILE LOW PRES PASSES SE OF LONG ISLAND. STRONG HIGH PRES
WILL THEN BUILD FROM THE W LATER SAT INTO SUNDAY NIGHT...THEN PASS
E ON MON. A WARM FRONT WILL APPROACH MON AFTERNOON AND
NIGHT...THEN LOW PRES WILL MOVE UP THE COASTAL PLAIN TUE INTO TUE
NIGHT...AND PASS TO THE NE ON WED.

&&

.NEAR TERM /THROUGH TONIGHT/...
DUE TO INSTABILITY AND DEEP-LAYERED CYCLONIC FLOW WITH THE UPPER
TROF AXIS MOVING ACROSS THE AREA THIS AFTERNOON THERE WILL BE
PLENTY OF CLOUDS. IN FACT...LATEST TEMPS TRENDS SUPPORTS LOWERING
HIGHS A FEW DEGREES...WITH MID TO UPPER 20S. SCT SNOW SHOWERS
WILL ALSO BE POSSIBLE ALONG AND AHEAD OF AN APPROACHING SFC TROF.

INCREASING MID LVL WINDS WILL ALSO ALLOW FOR GUSTS UP TO 35 MPH.
BRIEF PERIODS OF HAZARDOUS TRAVEL POSSIBLE IN SNOW AND WIND.

LAPSE RATES EASE TNGT WITH SUBSIDENCE IN THE WAKE OF THE UPPER
TROUGH. AS A RESULT WILL DRY THINGS OUT QUICKLY THIS EVE WITH
CLEARING SKIES.

&&

.SHORT TERM /FRIDAY/...
FAIR WEATHER TO START WITH A SFC HI PRES RIDGE OVER THE
AREA...THEN THE RIDGE IS WEAKENED BY LOW PRES PASSING OFFSHORE AND
AN APPROACHING ARCTIC FRONT. THE DATA SEEMS TO BE TRENDING FASTER
WITH APPROACHING UPR TROF AND CDFNT...SO WENT CLOSE TO THE 3Z
SREF FOR TIMING ACROSS WRN ZONES. THE GFS PRODUCES SOME LGT SNOW
ACROSS ERN AREAS ON THE PERIPHERY OF THE LOW. BUMPED UP THE DRY
POPS IN THE SREF ACROSS ERN ZONES TOO SLGT CHC FOR THIS. ANY WWD
TREND COULD BRING A DUSTING BY DARK ERN CT AND LI. A BLEND OF
GUIDANCE WAS USED FOR TEMPS WITH READINGS OVER 10F BLW AVG.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AN ARCTIC COLD FRONT APPROACHES FRIDAY NIGHT ALONG WITH A
SHORTWAVE FROM THE NORTH. AT THE SAME TIME...SHORTWAVE ENERGY
MOVES OFF THE MID ATLANTIC COAST. THE COMBINED ENERGY SHOULD
INITIATE SFC CYCLOGENESIS ALONG A BAROCLINIC ZONE TO OUR SOUTH
WITH THE LOW PASSING WELL SE OF THE 40N/70W BENCHMARK LATE AT
NIGHT. CHANCE OF SNOW DIRECTLY ASSOCIATED WITH THIS LOW LOOKS HIGH
ENOUGH TO RAISE POP TO LIKELY FOR ERN LONG ISLAND...WITH CHANCE
POP ACROSS MOST OF SRN CT AND LONG ISLAND...WITH ONLY MINOR ACCUMS
EXPECTED AS STRONGEST FORCING WITH THE LOW REMAINS WELL OFFSHORE.
ELSEWHERE COULD SEE ISOLD-SCT SNOW SHOWERS WITH THE APPROACHING
ARCTIC FRONT VIA DECREASING STABILITY AND CYCLONIC FLOW ALOFT.

AN ANOMALOUSLY COLD AIR MASS THEN POURS IN BEHIND THE COLD FRONT FOR
THE WEEKEND...WITH WINDS LIKELY APPROACHING ADVY CRITERIA IN NYC
METRO...LONG ISLAND AND PERHAPS THE HIGHER ELEVATIONS INLAND.
ANOTHER SHORTWAVE ARRIVES ALONGSIDE THE CORE OF COLD AIR ALOFT
DURING SAT/SAT EVENING. THE ATMOSPHERIC COLUMN DRIES...HOWEVER
THERE MAY STILL BE A CHANCE OF FLURRIES DURING THIS PERIOD.

AS FOR TEMPS SAT AND SAT NIGHT...THE CALENDAR DAY HIGH TEMP ON
SAT WILL PROBABLY OCCUR AT MIDNIGHT AS TEMPS COOL OFF OVERNIGHT
AND THEN STAY DOWN THROUGH THE DAY VIA STRONG CAA. TEMPS MAY
RECOVER A LITTLE ON SAT TO THE UPPER TEENS AND LOWER 20S...BUT
STRONG NW WINDS DURING THIS TIME SHOULD KEEP WIND CHILLS AT OR
BELOW ZERO THROUGH THE DAY. MODELS CONTINUE TO SHOW 850MB TEMPS
DROPPING TO -30C DURING THE NIGHT BEFORE RISING A FEW DEGREES
TOWARD DAYBREAK. BASED ON A SIMILAR SYNOPTIC SETUP LAST FEB WITH
WARMER TEMPS ALOFT...WENT NEAR OR SLIGHTLY BELOW THE LOW TEMPS
FCST BY ECMWF MOS...WITH LOWS CLOSE TO ZERO IN NYC AND ZERO TO 5
BELOW ELSEWHERE. THE COLD AIR COMBINED WITH WINDS WOULD PRODUCE
WIND CHILLS THAT WOULD WARRANT AN ADVISORY DURING SAT NIGHT INTO
SUNDAY MORNING...AND A WARNING FOR THE NORTHERN SUBURBS AND LONG
ISLAND.

REMAINING COLD BUT DRY SUNDAY/SUNDAY NIGHT AS HIGH PRESSURE
BUILDS IN...WITH HIGHS ONLY IN THE TEENS...AND LOWS IN THE TEENS
NYC METRO AND SINGLE DIGITS ELSEWHERE.

MODELS THEN IN DISAGREEMENT WITH THE TIMING OF THE NEXT SYSTEM TO
POTENTIALLY AFFECT THE REGION. HIGH PRESSURE SHIFTS OFFSHORE ON
MON...WITH POSSIBILITY OF OVERRUNNING LIGHT SNOWFALL REACHING
PARTS OF THE AREA BY LATE DAY. A LONGWAVE TROUGH THEN SHIFTS
THROUGH THE EASTERN STATES...WITH ITS AXIS PROGGED TO MOVE
THROUGH LATE TUE NIGHT. THIS THEN HELPS STRENGTHEN A SURFACE LOW
MOVING UP THE VICINITY OF THE EASTERN SEABOARD. LOW CONFIDENCE IN
THE EVOLUTION...TRACK AND TIMING OF THIS SYSTEM...AND CONSEQUENTLY
PRECIP TYPE LATE MON NIGHT INTO TUE MORNING. WITH A LEADING WARM
FRONT APPROACHING LATE MON NIGHT AND TEMPS WARMING ALOFT...THINK
SNOW WILL TRANSITION TO MIXED PRECIP LATE MON NIGHT AND THEN RAIN
DURING TUE MORNING. AFTER THAT...HEAVY RAIN LOOKS LIKE A GOOD BET
TUE INTO TUE NIGHT AHEAD OF THE LOW.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A LOW PRESSURE TROUGH MOVES THROUGH THIS AFTERNOON.

VFR. CHC SUB-VFR WITH -SHSN THIS AFTN...BUT ANY SNOW WOULD LIKELY BE
LIGHT WITH VSBYS AT 6SM OR ABOVE MOST OF THE TIME. ANY SNOW LIKELY
DOES NOT PREVAIL LONG ENOUGH FOR A MENTION IN TAFS...EVEN IN A TEMPO
GROUP.

WNW WINDS...PREVAILING SOUTH OF 310 MAGNETIC...WITH GUSTS AROUND 30
KT TODAY. WINDS SUBSIDE THIS EVENING.

...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: CHC -SHSN WITH BRIEF 3-5SM VSBYS BEFORE 20-
21Z. TIME FRAME. OCCASIONAL GUSTS UP TO 33-35KT POSSIBLE BEFORE 00Z.

KLGA FCSTER COMMENTS: CHC -SHSN WITH BRIEF 3-5SM VSBYS BEFORE 20-
21Z. TIME FRAME. OCCASIONAL GUSTS UP TO 33-35KT POSSIBLE BEFORE 00Z.

KEWR FCSTER COMMENTS: CHC -SHSN WITH BRIEF 3-5SM VSBYS BEFORE 20-
21Z. TIME FRAME. OCCASIONAL GUSTS UP TO 33-35KT POSSIBLE BEFORE 00Z.

KTEB FCSTER COMMENTS: CHC -SHSN WITH BRIEF 3-5SM VSBYS BEFORE 20-
21Z. TIME FRAME. OCCASIONAL GUSTS AROUND 30KT POSSIBLE BEFORE 00Z.

KHPN FCSTER COMMENTS: CHC -SHSN WITH BRIEF 3-5SM VSBYS BEFORE 20-
21Z. TIME FRAME. OCCASIONAL GUSTS AROUND 30KT POSSIBLE BEFORE 00Z.

KISP FCSTER COMMENTS: CHC -SHSN WITH BRIEF 3-5SM VSBYS BEFORE 21-
22Z. TIME FRAME. OCCASIONAL GUSTS UP TO 31-34KT POSSIBLE BEFORE 00Z.

.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRIDAY...VFR.
.SATURDAY...MOSTLY VFR. CHC SUB-VFR POSSIBLE IN BRIEF -SHSN. NW
GUSTS AROUND 35KT.
.SUNDAY...VFR.
.MONDAY...CHC SUB-VFR AND -SN PM.
.TUESDAY...SUB-VFR AND RAIN. CHC MIXED PCPN EARLY. SE-S GUSTS TO
30KT POSSIBLE. CHC LLWS.

&&

.MARINE...
WINDS WILL INCREASE OUT OF THE W TODAY WITH GALE COND EXPECTED.
GALE WARNING REMAINS UP THRU TNGT...THEN WINDS DECREASE THRU THE
DAY ON FRI.

WINDS THEN INCREASE TO SCA LEVELS LATE FRI NIGHT AS LOW PRESSURE
PASSES TO THE SE...AND GALES ARE LIKELY SAT INTO SAT NIGHT ON ALL
WATERS AFTER AN ARCTIC COLD FRONTAL PASSAGE...CONTINUING INTO
SUNDAY MORNING ON THE OCEAN. THE GALES COMBINED WITH SST IN THE
LOWER 40S AND AIR TEMPS IN THE 20S ON SAT...SINGLE DIGITS SAT
NIGHT AND TEENS ON SUNDAY WILL LEAD TO FREEZING SPRAY PROBLEMS...
WITH MODERATE TO HEAVY ACCRETION POSSIBLE ESPECIALLY SAT NIGHT
INTO SUNDAY MORNING.

QUIET CONDS EVENTUALLY RETURN SUNDAY AFTERNOON/NIGHT AS HIGH
PRESSURE BUILDS IN.

&&

.HYDROLOGY...
LIQUID EQUIVALENT OF LESS THAN A TENTH OF AN INCH IS EXPECTED THRU
FRI...AND 1/10 INCH OR LESS FRI NIGHT INTO SAT MORNING.

LOW PRESSURE MOVING UP THE COAST HAS POTENTIAL TO PRODUCE LIQUID
EQUIVALENT QPF AT LEAST 1 TO 2 INCHES. PART OF THIS WILL FALL AS
SNOW INITIALLY...BUT THEN RUNOFF VIA MELTING SNOW AND HEAVY RAIN
TUE INTO TUE NIGHT COULD CAUSE AT LEAST URBAN AND SMALL STREAM
FLOODING PROBLEMS. IT IS TOO EARLY TO SAY IF MAIN STEM RIVERS
WOULD BE AFFECTED.

&&

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

STATION......RECORD/FCST MINIMUM...RECORD LOW MAXIMUM/FCST HIGH
                 FOR 2/14                    FOR 2/14

NYC...........2 (1916)  /  1.............17 (1979) / 17
LGA...........1 (1979)  /  4.............15 (1979) / 18
JFK...........4 (1979)  /  2.............17 (1979) / 19
ISP...........7 (2015)  / -3.............26 (1987) / 15
EWR...........0 (1979)  /  0.............15 (1979) / 18
BDR...........3 (2015*) / -3.............18 (1979) / 15

*IN 1979 AS WELL

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...GALE WARNING UNTIL 6 AM EST FRIDAY FOR ANZ330-335-338-340-345-
     350-353-355.

&&

$$

SYNOPSIS...JMC/GOODMAN/DW
NEAR TERM...JMC/DW
SHORT TERM...JMC
LONG TERM...GOODMAN
AVIATION...JC
MARINE...JMC/GOODMAN
HYDROLOGY...JMC/GOODMAN
CLIMATE...//


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