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Area Forecast Discussion
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000
FXUS61 KOKX 020016
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
716 PM EST SUN MAR 1 2015

.SYNOPSIS...
A FRONTAL SYSTEM WILL APPROACH FROM THE WEST...THEN PASS THROUGH
TONIGHT AS WEAK LOW PRESSURE DEVELOPS SOUTH OF LONG ISLAND. 
HIGH PRESSURE WILL BRIEFLY BUILD IN MONDAY INTO MONDAY NIGHT... 
THEN PASS TO THE EAST ON TUESDAY. LOW PRESSURE WILL TRACK WELL
NORTH OF THE AREA TUESDAY NIGHT AND WEDNESDAY...WITH A WARM FRONT
LIFTING INTO THE AREA TUESDAY NIGHT...FOLLOWED BY A COLD FRONT
WEDNESDAY AND A REINFORCING COLD FRONT WEDNESDAY NIGHT. 
HIGH PRESSURE WILL THEN BUILD IN FOR THE REMAINDER OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A BAND OF MODERATE SNOW ACROSS THE SOUTH SHORE OF LONG
ISLAND AS OF 00Z...ALTHOUGH THINK SOME OF THIS IS A MIX OF
SNOW...SLEET AND/OR FREEZING RAIN. LOWER CORRELATION COEFFICIENT
VALUES STILL REMAIN JUST S OF LONG ISLAND...BUT EXPECT THEM TO
COME ONSHORE SHORTLY. WHERE IT IS STILL ALL SNOW TOWARDS THE
CENTRAL PART OF WESTERN SUFFOLK COUNTY...SNOWFALL RATES UP TO AN
INCH PER HOUR ARE LIKELY OCCURRING...HOWEVER...THE HIGHER
REFLECTIVITIES WILL PUSH TO THE EAST BY 01Z. 

SNOW TOTALS FORECAST STILL LOOKS ON TRACK WITH PERHAPS THE
EXCEPTION OF SOUTHERN NASSAU COUNTY. HAVE BUMPED UP TOTALS A BIT
THERE...AND COULD SEE SOME LOCATIONS IN EXTREME SOUTHERN PARTS OF
THE COUNTY END WITH AROUND 6 INCHES...BUT HAVE MAINTAINED THE ADVSY.

SOUTHERN PORTIONS OF NYC INTO SE METRO NJ ARE A MIX OF
SNOW...SLEET AND/OR FREEZING RAIN. TOUGH CALL HOW FAR NORTH THE
TRANSITION ZONE WILL GET BEFORE PCPN ENDS...BUT RECEIVED A REPORT
AS FAR N AS EAST RUTHERFORD OF MIXED PCPN. REGIONAL RADAR IMAGERY
INDICATES LIGHTER RETURNS ALREADY INTO THE LOWER HUDSON VALLEY
AND NE NJ...SO ACCUMULATING SNOW HAS GENERALLY ENDED HERE. 

AREAS IN AND S OF THE TRANSITION ZONE SHOULD SEE A GLAZE TO A
TENTH OF AN INCH OF ICE BEFORE PCPN WINDS DOWN AROUND MIDNIGHT OR
SO.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
HIGH PRESSURE APPROACHES FROM THE WEST ON MONDAY...THEN BUILDS
OVERHEAD ON TUESDAY. HIGHS ON MON WILL BE IN THE MID AND UPPER
30S...WITH A BRISK NW WINDS GUSTING TO 25-35 MPH. MUCH COLDER AIR
WILL FOLLOW FOR MON NIGHT...AND UNDERCUT MOS GUIDANCE BY 2-3 DEG
GIVEN DIMINISHING WINDS LATE AT NIGHT AND FRESH SNOW COVER...WITH
LOWS IN THE TEENS FOR NYC METRO AND LONG ISLAND...AND SINGLE
DIGITS FARTHER NORTH/WEST.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS ARE IN DECENT AGREEMENT AT H5 THROUGH THE WEEK...ALTHOUGH 
SLIGHT DIFFERENCES IN HEIGHTS BEGIN TO TAKE SHAPE DURING THE LATTER 
HALF FROM A DIGGING TROF IN THE MIDDLE OF THE COUNTRY.

RIDGING AT THE SFC AND ALOFT TRACKS MOVES OFFSHORE ON TUE. PCPN WILL 
OVERSPREAD THE AREA LATE TUE AFTN AS SNOW...BUT WITH INCREASING S-SW 
WINDS AND STRONG WAA TEMPS WILL WARM TUE EVE/NIGHT WITH SNOW 
CHANGING TO MIXED PCPN THEN RAIN FROM S TO N. WARM FRONT LIFTS 
TOWARDS THE AREA TUE NIGHT...BUT THERE IS SOME UNCERTAINTY IF THE 
LLJ WILL BE STRONG ENOUGH TO PUSH IT THROUGH AT THE SFC. CLIMATOLOGY 
SAYS NO WITH THE LOW SO FAR TO THE NW AND VERY COLD WATERS/ICE...SO 
HAVE GONE BELOW GUIDANCE WITH HIGHS WED...GENERALLY LOWER 40S WITH 
MID 40S POSSIBLE IN NYC METRO. 

THE COMBINATION OF THESE TEMPS AND RAINFALL WILL RESULT IN MELTING 
SNOWPACK WHICH COULD LEAD TO MINOR FLOODING ACROSS THE AREA ON WED. 
COLD FRONT MOVES ACROSS WED FOLLOWED BY A REINFORCING COLD FRONT WED 
NIGHT. THE NORTHERN EDGE OF THE PCPN SHIELD OF A SOUTHERN STREAM 
SYSTEM RIDING ALONG THIS SECONDARY BOUNDARY COULD KEEP PCPN 
LINGERING WED NIGHT INTO THU. MODELS REMAIN SPLIT ON THIS...GFS IS 
FURTHER SUPPRESSED THAN EC SO HAVE KEPT CHC POPS.

COLD AIR FILTERS IN BEHIND THE INITIAL COLD FRONT ON WED. THERMAL 
PROFILES SUPPORT A CHANGE BACK OVER TO SNOW WED NIGHT AND THU WITH 
ANY PCPN ASSOCIATED WITH THE SOUTHERN STREAM SYSTEM. ANOTHER SHOT OF 
ARCTIC AIR INFILTRATES THE AREA THU INTO FRI.

STRONG CANADIAN HIGH PRES THEN BUILDS TOWARDS THE AREA INTO THE 
WEEKEND WITH DRY WEATHER. TEMPS WILL REBOUND AROUND 5 DEGREES BELOW 
NORMAL NEXT WEEKEND WITH WAA DEVELOPING.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A FRONTAL SYSTEM WILL PASS THROUGH TONIGHT AS WEAK LOW PRESSURE 
DEVELOPS SOUTH OF LONG ISLAND. HIGH PRESSURE BUILDS MONDAY.

A WINTRY MIX OF FREEZING RAIN...SNOW AND SLEET APPEARS TO BE 
LIGHTENING FROM WEST TO EAST FOR NYC METRO AND LI TERMINALS. 
ELSEWHERE...MAINLY SNOW IS EXPECTED. EXPECT STEADY PRECIP TO WIND 
DOWN BY 2-4Z. AFTER MIDNIGHT...PRECIP SHOULD END ALTOGETHER...EXCEPT 
A LITTLE LONGER AT KISP AND KGON. EVEN THOUGH PRECIP ENDS...LOW END 
MVFR OR IFR CEILINGS SHOULD LINGER OVERNIGHT.

RETURN TO VFR MONDAY AFTER 11-13Z. 

WINDS WILL BE LIGHT AND VARIABLE...THEN WILL TURN TO THE WEST 5 TO
10 KTS AFTER MIDNIGHT. WINDS BECOME WEST/NORTHWEST AFTER 12Z...10 TO 
15 KTS. BY 15Z...FREQUENT GUSTS 20 TO 30 KTS ARE EXPECTED. WINDS 
SHOULD REMAIN TO THE LEFT OF 310 MAG FOR THE MOST PART MONDAY...BUT 
WILL BE CLOSE.

ADDITIONAL LIGHT SNOW ACCUMS ARE EXPECTED.
MOST LIKELY TOTAL RUNWAY ACCUMULATIONS: KGON/KISP...4-7 INCHES. 
KSWF/KHPN/KBDR/KTEB/KLGA/KJFK/KEWR...3-6 INCHES. 

.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MONDAY NIGHT-TUESDAY MORNING...VFR.
.TUESDAY AFTERNOON...CHANCE MVFR OR LOWER IN SNOW.
.TUESDAY NIGHT...IFR OR LOWER LIKELY. SNOW...CHANGING TO A WINTRY
MIX AFTER MIDNIGHT...AND THEN RAIN LATE AT ALL TERMINALS EXCEPT KSWF 
AND POSSIBLY CT TERMINALS. LLWS LIKELY.
.WEDNESDAY...IFR OR LOWER POSSIBLE IN ANY RAIN - WITH A BRIEF PERIOD 
OF ZR POSSIBLE IN THE MORNING AT KSWF. LLWS POSSIBLE IN THE MORNING.
.WEDNESDAY NIGHT-THURSDAY...MVFR OR LOWER POSSIBLE IN ANY
PRECIPITATION...OTHERWISE VFR. IF THERE IS PRECIPITATION...SHOULD 
CHANGE TO ALL SNOW WEDNESDAY NIGHT AND POSSIBLY CONTINUE INTO 
THURSDAY. NW WINDS G15-20KT POSSIBLE.
.THURSDAY NIGHT-FRIDAY...VFR. NW WINDS G15-20KT POSSIBLE THURSDAY
NIGHT. 

&&

.MARINE...
TRANQUIL TONIGHT...THEN WINDS INCREASE TO SCA 
LEVELS MON AND GRADUALLY DIMINISH MON NIGHT. EXPECT SUB-ADVY CONDS
ON TUE AS HIGH PRES BUILDS ACROSS. SCA CONDS POSSIBLE ON THE OCEAN
TUE NIGHT INTO THU BEHIND THE PASSAGE OF TWO COLD FRONTS...WITH A
TIGHT PRES GRADIENT. SUB-ADVY CONDS THEN EXPECTED THEREAFTER AS
THE PRES GRADIENT WEAKENS WITH ANOTHER BUILDING HIGH.

&&

.HYDROLOGY...
LIQUID EQUIVALENT QPF OF 4-6 TENTHS OF AN INCH EXPECTED TONIGHT.
WITH ALL OF THIS EXPECTED TO BE EITHER FROZEN OR FREEZING
PRECIPITATION...NO IMMEDIATE HYDROLOGIC IMPACT EXPECTED.

BETWEEN 1/2 TO 1 INCH OF LIQUID EQUIVALENT PCPN IS POSSIBLE LATE
TUE THROUGH WED. SOME OF THIS WILL FALL AS RAIN...THEREFORE THE
COMBINATION OF THIS AND MELTING SNOW PACK COULD CAUSE MINOR
FLOODING ISSUES. 

ICE WILL CONTINUE TO DEVELOP ON LOCAL AREA RIVERS AND STREAMS AS
TEMPERATURES REMAIN WELL BELOW AVERAGE.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR CTZ008-010>012.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR CTZ005>007-
     009.
NY...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR NYZ078>081.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR NYZ067>075-
     176>179.
NJ...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR NJZ002-004-
     006-103>108.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO MIDNIGHT EST MONDAY 
     NIGHT FOR ANZ330-335-338-340-345.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EST TUESDAY FOR 
     ANZ350-353-355.

&&

$$





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