Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KOKX 290240
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
940 PM EST SUN DEC 28 2014

.SYNOPSIS...
A COLD FRONT WILL PASS TO THE SOUTHEAST THIS EVENING.
HIGH PRESSURE WILL THEN SLOWLY BUILD IN AND DOMINATE THROUGH
FRIDAY...WHILE LOW PRESSURE PASSES WELL TO THE SOUTH ON TUESDAY.
ANOTHER LOW PRESSURE SYSTEM SHOULD APPROACH NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
FORECAST IS MORE OR LESS ON TRACK. SLOWED DOWN THE CLEARING WITH
THIS UPDATE AS IT LOOKS LIKE THE HIGHER CLOUDS WILL TAKE A BIT
LONGER TO MOVE OUT. THE CMC LOOKS TO HAVE A GOOD HANDLE ON THE
CLOUDS BASED ON CURRENT IR IMAGERY. BECAUSE THE CLOUDS WILL BE
SLOWER TO CLEAR...LOW TEMPS WERE RAISED A FEW DEGREES ACROSS THE
AREA AND HOURLY TEMPS WERE ADJUSTED SO THAT THEY REFLECT A SLOWER
DROP OFF THAN IN THE PREVIOUS FORECAST. ALSO...BASED ON CURRENT
RADAR...THE ONLY AREAS THAT SHOULD SEE ANY SPRINKLES OR LIGHT RAIN
SHOWERS IS OVER THE OCEAN WATERS.

COLD FRONT PASSES SOUTHEAST OF THE REGION THIS EVENING. A PASSING
SHORTWAVE COULD STILL PRODUCE A FEW SPITS OF LIGHT RAIN OVER NYC
METRO AND LONG ISLAND THIS EVENING...OTHERWISE SKIES SHOULD CLEAR
FROM THE NW...WITH COLDER LOW TEMPS RANGING FROM THE UPPER 30S
IN/JUST OUTSIDE NYC...TO THE LOWER/MID 30S ACROSS THE REST OF NYC
METRO AND THE COAST...TO THE MID/UPPER 20S INLAND.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
HIGH PRESSURE WILL START TO SLOWLY BUILD FROM THE WEST...WITH
MOSTLY CLEAR SKIES AND COLDER TEMPS. A WEAKENING SECONDARY COLD
FRONT SHOULD MOVE THROUGH FROM THE NORTH ON MON...SO AFTER MIDDAY
HIGHS IN THE LOWER/MID 40S...EXPECT SLOWLY FALLING TEMPS MON
AFTERNOON AND THEN MUCH COLDER AIR FOR MON NIGHT. LOW TEMPS AT
DAYBREAK TUE SHOULD BE NEAR 30 IN MIDTOWN NYC...IN THE 30S MOST
ELSEWHERE...AND IN THE UPPER TEENS IN THE COLDER INTERIOR VALLEYS
AND LONG ISLAND PINE BARRENS.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
STARTING OFF ON TUESDAY...MORE OF A CONSENSUS IN MODEL GUIDANCE NOW
WITH DRY WEATHER PREVAILING. CURRENT AND PREVIOUS RUNS OF
CMC...ECMWF...AND GFS KEEP PRECIP WELL SOUTH OF THE REGION IN
ASSOCIATION WITH THE WAVES OF LOW PRESSURE RIDING ALONG THE
STALLED FRONT. EVEN MAJORITY OF GFS ENSEMBLE MEMBERS KEEP THIS
PRECIP SUPPRESSED TO THE SOUTH.

OVERALL...QUASI-ZONAL MID TO UPPER LEVEL FLOW THROUGH FRIDAY WITH
A RIDGING TREND FOR NEXT WEEKEND. THE MAIN UPPER LEVEL JET WILL BE
ALIGNED IN A SIMILAR FASHION AND MOVING SLIGHTLY SOUTH OF THE
REGION FOR MIDWEEK BEFORE TRENDING BACK NORTH OF THE AREA FOR THE
WEEKEND.

AT THE SURFACE...VERY STRONG HIGH PRESSURE OF AT LEAST 1050MB
BUILDS INTO THE NORTHWEST PART OF THE COUNTRY AND THIS SINKS
SOUTHEAST THROUGH MIDWEEK. THIS WILL BE A SOURCE FOR VERY COLD AIR
AND PERIODIC SHORTWAVES WILL MOVE ACROSS THE LOCAL REGION TO HELP
WITH ADVECTING THE COLDER AIR MASS INTO THE REGION.

THE LOW LEVEL ENVIRONMENT WILL ALSO BECOME VERY DRY AS DIAGNOSED
BY FORECAST LAYER PRECIPITABLE WATERS AROUND A TENTH OF AN INCH
TUESDAY THROUGH THURSDAY. THIS WILL BE ON AN INCREASING TREND
TOWARDS THE WEEKEND BUT AGAIN THERE IS UNCERTAINTY WITH THE
FORECAST FOR DAY 7 THROUGH DAY 8 TIME FRAME.

THIS UNCERTAINTY IS CONVEYED BY NEARLY A 90 DEGREE PHASE SHIFT
BETWEEN CONSECUTIVE RUNS OF THE ECMWF WITH REGARDS TO UPPER LEVEL
HEIGHT CONTOUR ORIENTATION. HOWEVER...DID INCREASE POPS A LITTLE
WITH AGREEMENT ON PRECIP BETWEEN DGEX...GFS...AS WELL AS SOME GFS
ENSEMBLE MEMBERS. JUST A MATTER OF PRECIP TYPE. THIS FORECAST HAS
A MIX OF RAIN AND SNOW...SNOW PROBABLY AT ONSET DUE TO WET BULB
COOLING AND THEN CHANGING OVER TO RAIN WITH MORE SOUTHERLY FLOW
FOR NEXT WEEKEND. HOWEVER...THE CONFIDENCE IS VERY LOW FOR DAY 7
AND DAY 8 TIME FRAME...SO SUBSEQUENT FORECASTS COULD VARY WITH
TIMING...PLACEMENT...AS WELL AS PRECIP TYPES.

CONCERNING TEMPERATURES...TUESDAY THROUGH THURSDAY IS WHEN THE BULK
OF THE COLD AIR MASS IS IN PLACE WITH HIGHS HOVERING NEAR TO
SLIGHTLY ABOVE FREEZING ON AVERAGE. NEAR NORMAL TEMPERATURES RETURN
BY FRIDAY AND POSSIBLY ABOVE NORMAL FOR THE WEEKEND. AGAIN...LOWER
CONFIDENCE WITH TEMPERATURES NEXT WEEKEND DUE TO AFOREMENTIONED
UNCERTAINTY.

DRY WEATHER IN THE LONG TERM UNTIL NEXT WEEKEND WITH THE NEXT
APPROACHING LOW PRESSURE SYSTEM.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
A COLD FRONT CONTINUES TO MOVE EAST OVERNIGHT...FOLLOWED BY HIGH
PRESSURE BUILDING IN FROM THE WEST.

NORTHWEST WINDS PREVAIL THROUGH THE TAF PERIOD...OR THROUGH THE DAY
MONDAY. SPEEDS INITIALLY AROUND 9-13 KTS SHOULD LIGHTEN SOMEWHAT
OVERNIGHT. ON MONDAY...SPEEDS WILL BE GENERALLY 10 KTS OR LESS.

FOR NYC METRO...WIND DIRECTION WILL PREDOMINATELY BE TO THE RIGHT OF
310 MAGNETIC.

ANY LINGERING SCATTERED TO BROKEN STRATOCU THIS EVENING WILL
CLEAR...WITH MAINLY MID AND HIGH LEVEL CLOUDS FORECAST OVERNIGHT.
VFR.

.OUTLOOK FOR 00Z TUE THROUGH FRI...
.MON NIGHT-WED...VFR.
.THU...VFR. SW WIND GUSTS TO 25 KT POSSIBLE.
.FRI...VFR.

&&

.MARINE...
COLD FRONT SHOULD MAINTAIN A MODERATE NW FLOW TONIGHT OUT EAST...
WITH WIND GUSTS CLOSE TO 25 KT AND 5-FT SEAS ON THE OCEAN E OF
MORICHES INLET AT LEAST INTO THIS EVENING IF NOT ALL NIGHT.
EXTENDED SCA OUT EAST THROUGH TONIGHT. THEN SUB SCA CONDS FORECAST
MONDAY THROUGH TUESDAY.

SCA CONDS ARE AGAIN POSSIBLE LATE TUESDAY NIGHT THROUGH WEDNESDAY...WITH
A BETTER CHANCE WEDNESDAY NIGHT THROUGH FRIDAY...WHEN OCEAN SEAS
ARE FORECAST TO REACH 5-7 FT MAINLY EAST OF FIRE ISLAND INLET.
THIS WILL BE COINCIDING WITH COLDER AIR MOVING IN AND BETTER
MIXING OVER THE RELATIVELY WARMER WATERS.

&&

.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION OF 1/2 INCH OR MORE EXPECTED THROUGH
FRI. WIDESPREAD PRECIP POSSIBLE FOR NEXT WEEKEND...BUT IT IS TOO
EARLY TO TELL IF IT WILL BE SIGNIFICANT.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR ANZ350.

&&

$$
SYNOPSIS...GOODMAN/JM
NEAR TERM...GOODMAN/JM/JP
SHORT TERM...GOODMAN
LONG TERM...JM
AVIATION...PW
MARINE...GOODMAN/JM/JP
HYDROLOGY...GOODMAN/JM







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.