Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 020235
AFDOKX

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

.SYNOPSIS...
WEAK LOW PRESSURE SOUTH OF LONG ISLAND TRACKS TOWARDS NOVA SCOTIA
OVERNIGHT WITH A COLD FRONT MOVING ACROSS THE AREA LATE. 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/...
PCPN WINDING DOWN ACROSS NE NJ...LOWER HUDSON VALLEY AND NYC WITH
JUST ONE LAST BAND OF PCPN TO MOVE THROUGH. A FEW MORE HOURS TO GO
EAST OF HERE...WITH PCPN ENDING COMPLETELY SHORTLY AFTER MIDNIGHT.
DUAL POL CC IS INDICATING MIXING REMAINING OVER SOUTH SHORE...KFOK
JUST CHANGED OVER TO FZRA...SO HAVE BACKED OFF ON THE EXTENT OF
MIXING ACROSS LONG ISLAND AND KEPT IT GENERALLY CONFINED TO THE
SOUTH SHORE.

WILL KEEP ADVSYS/WARNINGS UP UNTIL THE NEXT UPDATE WITH PCPN
CONTINUING ALTHOUGH THE REAL ACCUMULATING SNOWS OVER
AFOREMENTIONED WESTERN AREAS IS ENDING.

AREAS EXPERIENCING FZRA SHOULD EXPECT LESS THAN 1/10 OF AN INCH OF
ACCUM.

&&

.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 /02Z MONDAY THROUGH FRIDAY/...
A FRONTAL SYSTEM WILL PASS THROUGH TONIGHT AS WEAK LOW PRESSURE
DEVELOPS SOUTHEAST OF LONG ISLAND. HIGH PRESSURE BUILDS MONDAY.

A WINTRY MIX OF FREEZING RAIN...SNOW AND SLEET WILL LIGHTEN AND END
BY 5-7Z...WEST TO EAST FOR CSTL AIRPORTS. ACROSS THE INTERIOR...ANY
LIGHT SNOW WILL ALSO END FROM WEST TO EAST.

GENERALLY EXPECT LOW END MVFR OR IFR CONDITIONS TONIGHT...ALTHOUGH
VSBYS SHOULD IMPROVE ONCE THE PRECIPITATION ENDS.

A RETURN TO VFR CAN BE EXPECTED MONDAY AFTER 11-13Z.

WINDS WILL BE LIGHT AND VARIABLE...THEN WILL TURN TO THE WEST 5 TO
10 KTS WELL 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 TO THAT DIRECTION AT TIMES.

ADDITIONAL LIGHT SNOW ACCUMS ARE EXPECTED.
MOST LIKELY TOTAL RUNWAY ACCUMULATIONS:
KGON/KISP/KBDR...4-7 INCHES.
KSWF/KHPN/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...
ANOTHER 1-2 TENTHS OF LIQUID EQUIVALENT PCPN IS EXPECTED THROUGH
MIDNIGHT...HIGHEST AMOUNTS E. 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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