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Area Forecast Discussion
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000
FXUS61 KOKX 190919 CCA
AFDOKX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NEW YORK NY
417 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/...
WITH LOW PRESSURE EXITING WELL UP INTO NORTHERN LATITUDES...THE 
LOCAL REGION WILL BE MORE UNDER THE INFLUENCE OF HIGH PRESSURE TODAY 
AND RIDGING ALOFT. THERE WILL LESSENING CYCLONIC FLOW ALOFT THROUGH 
THE DAY TODAY. THE PRESSURE GRADIENT WILL WEAKEN WITH BOUNDARY LAYER 
WINDS LOWERING IN RESPONSE.

ONE MAIN FACTOR WITH THE FORECAST IS THE CURRENT SUBSIDENCE 
INVERSION IN THE LOW LEVELS AND WHETHER OR NOT THIS WEAKENS THROUGH 
THE DAY TODAY. IF IT WEAKENS...CLOUDS WILL DECREASE MORE AND ALLOW 
FOR MORE SUN AND IT IF HOLDS...A MOSTLY CLOUDY DAY IS IN STORE. 

MODELS HAVE HAD DIFFICULTY RESOLVING THE LOWER CLOUDS BEING 
EXPERIENCED IN DIFFERENT LOCATIONS SO FAR SO A MANUAL ADJUSTMENT
UPWARD WAS MADE TO MODEL CLOUD COVERAGE WITHIN THE FORECAST
DATABASE FOR TODAY. HOWEVER...A DOWNWARD TREND WAS CONVEYED GOING
INTO THE EVENING WITH THE CENTER OF HIGH PRESSURE MOVING CLOSER TO
THE LOCAL REGION.

FOR MAX TEMPS...USED A BLEND OF GMOS AND MAV GUIDANCE. THE MAV 
GUIDANCE HAD RELATIVELY LESS ERROR COMPARED TO MET GUIDANCE FOR HIGH 
TEMPERATURES THE PREVIOUS DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
FOR TONIGHT...THERE IS STILL SOME UNCERTAINTY WITH LINGERING LOW 
CLOUDS AND HOW MUCH OF A LOW LEVEL INVERSION THERE WILL BE.
OTHERWISE...WITH HIGH PRESSURE CONTINUING TO BUILD INTO THE
REGION...WINDS WILL FURTHER LOWER. THEREFORE...THE RADIATIONAL
COOLING WILL BE DEPENDENT MAINLY ON THE CLOUD COVERAGE. WENT WITH
SOME SCATTERED CLOUD COVERAGE AND AS A RESULT OF THAT USED A BLEND
OF GMOS/MET/MAV GUIDANCE FOR LOWS. THIS PRESENTS LOWS A FEW
DEGREES HIGHER BUT STILL...THESE LOW TEMPERATURES ARE 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 IS FLOODING 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 /09Z FRIDAY THROUGH TUESDAY/...
A STRONG LOW PRESSURE SYSTEM WILL SPIN ACROSS THE CANADIAN MARITIMES
THROUGH 06Z SAT.

UNTIL SUNRISE...BKN 040-060 CIGS. ISOLATED MVFR CIGS ARND 030 
POSSIBLE. WINDS GENERALLY 300-340 DEGREE MAGNETIC OCCASIONAL GUSTS 
TO 20 KT AT NYC METRO.

TODAY...SCT-BKN 040-060 CIGS. ISOLATED MVFR CIGS ARND 030 POSSIBLE 
UNTIL 15Z. WINDS GENERALLY 320-360 DEGREE MAGNETIC WITH SPEEDS OF 
10-15 KT GUSTS NEAR 20 KT UNTIL 22Z.

THIS EVENING...VFR WITH WINDS DECREASING.

...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 06Z SAT THROUGH WED...
.LATE FRI NIGHT-SAT...VFR. 
.SAT NIGHT...MVFR OR LOWER IN CIGS. LIGHT EAST WINDS.
.SUNDAY...MVFR OR LOWER IN CIGS. LIGHT EAST WINDS.
.MON...MVFR OR LOWER POSSIBLE IN SE FLOW.
.MON NIGHT-TUE...IFR LIKELY AT TIMES IN RAIN...CIGS AND VSBYS. SE 
WINDS 10-20 KT. 
.WED...HIGH IMPACT EVENT POSSIBLE...IFR LIKELY WITH HEAVY RAIN AND
STRONG GUSTY SE WINDS 25KT+ SHIFTING TO W LATE.

&&

.MARINE...
THE MAIN FEATURE WILL BE HIGH PRESSURE GRADUALLY BUILDING IN FROM 
THE WEST THROUGH SATURDAY. FOR EARLY 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 25KT 
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 PRECIP 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
SHORT TERM...JM
LONG TERM...JC
AVIATION...GC
MARINE...JM
HYDROLOGY...JC/JM









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