Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 191451
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
951 AM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE BUILDS IN FROM THE WEST AND MOVES OVER THE NORTHEAST
INTO EARLY NEXT WEEK. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN
AFFECT THE REGION THROUGH THE MID-WEEK PERIOD.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANOTHER DAY OF CHASING STRATUS/STRATO-CU. THERE`S A FEATURE OVER
THE KHVN TO KOXC AS OF 1415Z THAT IS ADVECTING SOUTH SOUTHWEST.
THERE`S ANOTHER EAST OF MONTAUK. ONLY GUESS IS THESE ARE SOME
SORT OF GRAVITY WAVES TRAPPED IN THE DUCKING INVERSION.

USUAL NEAR TERM CLOUD GUIDANCE TOOLS SUGGEST A SUNNY AFTERNOON.
THE NAM12 06Z RUN THOUGH SEEMS TO HAVE A BETTER HANDLE ON WHAT`S
OCCURRING CURRENTLY. HAVE THUS KEPT CLOUD COVER IN (AS WAS
PREVIOUSLY FCST).

WITH A 25 DEGREE SUN ANGLE (WINTER SOLSTICE IS SUNDAY 603 PM) AND
THE EXPECTED CLOUD COVER - HAVE LOWERED TEMPS TO THOSE OF THE
LATEST LAMP.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
FOR TONIGHT...UNCERTAINTY REMAINS WITH THE STRATUS...THUS LOW TEMPS
MAY ONCE AGAIN BE OFF BY 5 DEGREES OR MORE (HIGHER THAN FCST). BASED
ON 06Z NAM...IT APPEARS AT LEAST EASTERN SECTIONS WILL CLEAR AND
HAVE NOT CHANGE FCST AT THIS TIME.

OTHERWISE...WITH HIGH PRESSURE CONTINUING TO BUILD INTO THE
REGION...WINDS WILL FURTHER LOWER. THEREFORE...THE RADIATIONAL
COOLING DEPENDS ON CLOUD COVERAGE...WHICH IS UNCERTAIN AT THIS
TIME. FOR NOW...A BLEND OF GMOS/MET/MAV GUIDANCE FOR LOWS IS
USED....WHICH IS REMARKABLY LOWER THAN RECENT NIGHTS...RANGING
FROM THE LOWER 20S TO NEAR 30.

FOR SATURDAY...SAME SCENARIO HERE WITH HIGH PRESSURE CONTINUING TO
BUILD IN. THIS DAY WILL FEATURE LOWER MAX TEMPS THOUGH BECAUSE OF
LIMITED VERTICAL MIXING. THE WINDS IN THE LOW LEVELS WILL BE
TRANSITIONING TO LIGHT N-NE FLOW...HELPING TO ADVECT IN SOME COOLER
AIR. MAX TEMPS AGAIN WERE A BLEND OF GMOS/MET/MAV GUIDANCE AND UP TO
3-4 DEGREES COOLER ALONG THE COAST THAN THE PREVIOUS DAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
AS HIGH PRESSURE IN THE VICINITY OF MAINE SAT NIGHT SLOWLY SHIFTS
EAST THROUGH MONDAY...MOISTURE STREAMS INTO THE TRI STATE AREA FROM
OFF THE WATERS. DURING SATURDAY NIGHT...THIS MOISTURE WILL BE
SHALLOW...SUPPORTING ONLY LIGHT/VERY LIGHT PCPN. SLIGHT CHC POPS FOR
ROUGHLY THE SE HALF OF THE CWA. MID LEVELS WILL PROBABLY BE DRY WITH
A LACK OF ICE NUCLEI. THERE IS HOWEVER A CHANCE THAT THE COLDEST
TEMPERATURE IN THE SATURATED LAYER CLOSER TO THE SURFACE WILL BE
COLD ENOUGH TO SUPPORT ICE CRYSTALS FOR LIGHT SNOW. WOULD BE MORE
CONFIDENT FOR SNOW AS A PCPN TYPE IF THE LOW LEVEL FLOW WAS MORE
VEERED TO THE EAST (SEA SALT AS NUCLEI)...BUT IN ANY CASE...OVERALL
CHANCES OF PCPN ARE LOW. HAVE GONE WITH A MIX OF LIGHT
SNOW/RAIN/FREEZING RAIN DEPENDING ON SURFACE TEMPS.

MID LEVELS MOISTEN SUNDAY MORNING WITH A SHORTWAVE PASSING
THROUGH...SO FREEZING RAIN IS PROBABLY OUT OF THE EQUATION BY THIS
TIME. SLIGHT CHC OF LIGHT SNOW OR RAIN THEREFORE FOR SUNDAY.

POPS INCREASE MONDAY...MAINLY IN THE AFTERNOON...AS A WAVE OF LOW
PRESSURE FORMS ALONG A STALLED BOUNDARY NEAR CAPE HATTERAS AND
PUSHES NORTH. A SLIGHT CHANCE OF LIGHT RAIN AND SNOW IN THE
MORNING...THEN A CHANCE OF RAIN IN THE AFTERNOON AS THERMAL PROFILES
BECOME TOO WARM FOR ANYTHING ELSE. WILL ALSO NEED TO MONITOR FOR THE
POSSIBILITY OF MINOR COASTAL FLOODING STARTING WITH THE MONDAY
MORNING HIGH TIDE CYCLE. WINDS WILL NOT BE PARTICULARLY STRONG
LEADING UP IT...BUT THEY WILL BE ENE FOR SOME TIME AND TIDES WILL BE
ON THE HIGHER SIDE ASTRONOMICALLY AS THERE IS A NEW MOON ON SUNDAY.

FOR TUES AND WEDS...A MUCH STRONGER LOW PRESSURE SYSTEM AFFECTS THE
AREA. LOOKS LIKE A PRIMARY LOW CENTER MOVES ACROSS THE GREAT LAKES
WHILE A SECONDARY LOW CENTER FORMS BEFORE PASSING NEARBY WEDS
EVENING. THIS STILL LOOKS LIKE AN ALL-RAIN EVENT. HAVE CAPPED POPS
AT 50% FOR TUES DUE TO UNCERTAINTY WITH NORTHWARD ADVANCEMENT OF THE
WEAKENING INITIAL LOW THAT HAD BEEN APPROACHING FROM THE CAROLINA
COAST. MORE CONFIDENCE IN RAINFALL DURING WEDS AS THE SECONDARY LOW
CENTER OF THE STRONGER STORM SYSTEM PASSES NEARBY.

MINOR STREET FLOODING IS POSSIBLE DURING WEDS/WEDS EVENING. STILL A
LOW CHANCE OF CONVECTION ENHANCING THE RAINFALL AS SOME ELEVATED
INSTABILITY IS FORECAST BY BOTH GFS AND ECMWF. WINDS WILL PROBABLY
BE THE BIGGER CONCERN WITH A TIGHTENING PRESSURE GRADIENT AND A
DECENT LOW LEVEL JET PASSING THROUGH SOME TIME ON WEDS
AFTERNOON/EVENING. A WIND ADVISORY COULD EVENTUALLY BE NEEDED FOR
SOME AREAS.

RIGHT NOW IT APPEARS THAT PCPN WILL BE OVER BY CHRISTMAS MORNING.
HOWEVER...WITH A FAIRLY STRONG WESTERLY FLOW...LAKE EFFECT RAIN/SNOW
SHOWERS COULD REACH THE NW ZONES. NEAR-WIND ADVISORY CRITERIA COULD
STILL BE MET. TEMPERATURES ON CHRISTMAS MOSTLY 40-45.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
A STRONG LOW PRESSURE SYSTEM WILL MOVE FURTHER EAST ACROSS THE CANADIAN
MARITIMES AS HIGH PRESSURE MOVES EAST TOWARD THE REGION BY 12Z SAT.

TODAY...CIGS 030-040FT UNTIL 22Z. LOW CHC OF BRIEF MVFR CIGS UNTIL 15Z.
WINDS 310-350 DEGREES MAGNETIC AT SPEEDS OF 10-15KT WITH GUSTS TO ARND
20KT UNTIL 22Z.

TONIGHT...VFR WITH WINDS DECREASING TO LESS THAN 10 KT.

SATURDAY...VFR WITH CIGS ABV 030FT DEVELOPING AFT 18Z. LIGHT N-NE
WINDS LESS THAN 10 KT.

     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.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

.OUTLOOK FOR 18Z SAT THROUGH WED...
.SAT NIGHT...VFR CIGS POSSIBLY MVFR. LIGHT EAST TO NORTHEAST WINDS.
.SUNDAY...MVFR CIGS. LIGHT NORTHEAST WINDS. SLIGHT CHC OF AM SNOW/PM RAIN.
.MON...MVFR OR LOWER POSSIBLE IN E-SE FLOW. CHC OF RAIN.
.MON NIGHT-TUE...IFR LIKELY AT TIMES IN RAIN...CIGS AND VSBYS. E-SE
WINDS 10-20 KT.
.WED...HIGH IMPACT EVENT POSSIBLE...IFR LIKELY WITH HEAVY RAIN AND
STRONG GUSTY SE WINDS 25KT+ SHIFTING TO SW LATE.

&&

.MARINE...
HIGH PRESSURE GRADUALLY BUILDING IN FROM THE WEST THROUGH
SATURDAY. FOR THE REST OF THIS MORNING...A STEEP ENOUGH PRESSURE
GRADIENT BETWEEN THE HIGH TO THE WEST AND LOW NEAR NEWFOUNDLAND
WILL ALLOW FOR SOME GUSTY WINDS. HOWEVER...ANY 25 KT GUSTS ARE
ONLY EXPECTED TO BE OCCASIONAL WITH MOST GUSTS BELOW 25 KT. THE
LOW RACES TO THE NORTHERN LATITUDES DURING THE DAY AND HIGH
PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST. THIS WILL ALLOW
FOR A STEADY DECREASE IN THE PRESSURE GRADIENT. THE BOUNDARY LAYER
FLOW AND SURFACE WINDS WILL DECREASE IN RESPONSE.

OVERALL...MAINLY SUB SCA CONDITIONS SHOULD PREVAIL THROUGH
SATURDAY.

TRANQUIL CONDITIONS CONTINUE THROUGH THE REST OF THE WEEKEND. WINDS
AND SEAS BUILD ON MONDAY WITH A TIGHTENING PRESSURE GRADIENT. SCA
CONDS THEN LIKELY FOLLOW MON NIGHT AND TUES.

&&

.HYDROLOGY...
DRY WEATHER IS FORECAST THROUGH SATURDAY WITH ONLY SLIGHT CHANCES
OF PCPN SATURDAY NIGHT AND SUNDAY. NO HYDRO IMPACTS EXPECTED INTO
EARLY NEXT WEEK.

1/4 TO 1/2 INCH OF RAIN IS POSSIBLE MONDAY AFTERNOON THROUGH TUESDAY
AS LOW PRES PASSES SOUTH OF LONG ISLAND. NO HYDROLOGICAL IMPACTS
EXPECTED.

RAIN ON WEDNESDAY/WEDS NIGHT MAY AVERAGE 1-2 INCHES ACROSS THE
REGION. MINOR STREET FLOODING IS POSSIBLE.

&&

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

&&

$$
SYNOPSIS...JC/JM
NEAR TERM...JM/TONGUE
SHORT TERM...JM/TONGUE
LONG TERM...JC
AVIATION...IRD
MARINE...JM/TONGUE
HYDROLOGY...JC/JM







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