Winter Storm Watch 3, NWS New York, NY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1239 AM EST MON JAN 17 2011

.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD OVER THE AREA ON
MONDAY...AND THEN SLOWLY RETREAT NORTHEAST MONDAY NIGHT INTO
TUESDAY. DEVELOPING LOW PRESSURE WILL MOVE NORTHEAST FROM NEAR THE
CAROLINA COAST MONDAY NIGHT...TO NORTH OF NOVA SCOTIA BY WEDNESDAY
EVENING. WEAK HIGH PRESSURE WILL THEN BUILD IN THROUGH THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LARGE AREA OF HIGH PRESSURE OVER THE GREAT LAKES WILL SETTLE OVER
THE REGION BY EARLY MORNING. MID LEVEL CLOUDS MOVING IN TONIGHT AND
LIGHT NW FLOW SHOULD LIMIT RADIATIONAL COOLING SOMEWHAT...SO SIDED
WITH SOMEWHAT LESS COLD 01Z LAV GUIDANCE FOR OVERNIGHT TEMPS/MINS...
WITH TEENS IN NYC AND ALONG THE COAST...AND SINGLE DIGITS INLAND.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL PASS THROUGH NEW ENGLAND DURING THE DAY MONDAY
AND THEN OFFSHORE...WITH RETURN FLOW DEVELOPING MONDAY NIGHT. THE
CORE OF THE COLD AIRMASS WILL BE LOCATED OVER THE REGION EARLY IN
THE DAY...AND EVEN WITH MOSTLY SUNNY SKIES MONDAY...TEMPS WILL HAVE
A DIFFICULT TIME WARMING UP. MAV/MET WERE IN GOOD AGREEMENT FOR
HIGHS...RANGING FROM THE UPPER TEENS TO LOW 20S OVER INTERIOR
SECTIONS TO THE MID 20S NEAR THE COAST.

LOW PRESSURE DEVELOPS NEAR THE OUTER BANKS MONDAY NIGHT AND BEGINS
TO MOVE UP THE COAST. THE LOW WILL INTENSIFY AS IT MOVES UP THE
COAST...WITH PRECIPITATION MOVING INTO THE REGION AFTER MIDNIGHT.
FORECAST UNCERTAINTIES CONTINUE TO AT LEAST SOME DEGREE OVER THE
TRACK OF THE STORM...WITH THE NAM BRINGING THE LOW CENTER NEAR THE
BENCHMARK 40N/70W AND THE GFS/ECMWF BRINGING THE STORM INSIDE THE
BENCHMARK. THIS IS THE PREFERRED SOLUTION.

TEMPERATURES WILL BE GRADUALLY WARMING UP OVERNIGHT WITH
ONSHORE FLOW FROM THE OFFSHORE HIGH AND THE LOW TO OUR SOUTH.
SURFACE TEMPS WILL REMAIN BELOW FREEZING OVERNIGHT HOWEVER...SO
HIGH CONFIDENCE THAT PRECIP BEGINS AS SNOW MONDAY NIGHT. DURING
THE EARLY MORNING HOURS...A NOSE OF WARM AIR ALOFT DEVELOPS ABOUT
850MB. THIS WILL LIKELY CHANGE PRECIP TO A MIX OF SLEET AND
FREEZING RAIN FOR A PERIOD OF TIME DURING THE MORNING. WITH WARM
AIR REMAINING ALOFT AND SURFACE TEMPERATURES CONTINUING TO
GRADUALLY INCREASE...FROZEN PRECIP IS EXPECTED TO CHANGE TO RAIN
TUESDAY MORNING...FIRST OVER THE SOUTHERN PART OF THE
REGION...NJ/NYC/LONG ISLAND...AND GRADUALLY WORKING ITS WAY NORTH
THROUGHOUT THE DAY. FORECAST UNCERTAINTIES CONTINUE WITH EXACTLY
HOW QUICKLY TEMPERATURES AT THE SURFACE AND ALOFT WARM UP...AND
THEREFORE THE EXACT LOCATION AND DURATION OF SNOWFALL/MIXED
PRECIP. WITH THIS FORECAST PACKAGE...EXPECTING AROUND AN INCH OR AN
INCH AND A HALF OF SNOW NEAR NYC...LESS THAN ONE INCH OVER LI AND
COASTAL CT...AND POSSIBLE ADVISORY LEVEL SNOWFALL OVER THE LOWER
HUDSON VALLEY. THE GREATEST THREAT FOR ICE ACCUMULATION IS NORTH
OF NEW YORK CITY...BUT HERE ACCUMULATIONS ARE LIKELY TO BE LESS
THAN 1/4 OF AN INCH.

SO IN TERMS OF HAZARDS...CONFIDENCE TOO LOW AT THIS POINT TO ISSUE A
WINTER STORM WATCH AND A LITTLE TOO EARLY FOR ADVISORIES. THIS
WILL BE RE-EVALUATED BY THE NIGHT SHIFT...WITH POSSIBLE CHANGES IF
MODELS SHOW DIFFERENCES IN STORM TRACK AND TEMPERATURE PROFILES.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
GOOD AGREEMENT AMONG MODEL GUIDANCE WED-THU...THEN VERY POOR MODEL
AND RUN TO RUN CONSISTENCY THEREAFTER LEADING TO A LOW CONFIDENCE
FORECAST. BROAD MEAN TROUGH LOOKS TO DOMINATE THE ENTIRE CONUS
THROUGH THE END OF THE WEEK...BUT THE UPPER PATTERN DIVERGES FOR
NEXT WEEKEND...RESULTING IN LARGE DIFFERENCES WITH THE LOCAL WEATHER
PATTERN. HAVE GENERALLY FOLLOWED HPC GUIDANCE FROM THU NIGHT ON AS A
RESULT.

LOW PRES OVER THE GULF OF MAINE WED MORNING WILL CONTINUE TO DEEPEN
AS IT TRACK NE INTO THE CANADIAN MARITIMES. PRECIP ENDS...BUT WINDS
WILL INCREASE WITH STRONG CAA WED NIGHT. HIGH PRES BUILDS TOWARDS
THE AREA WHILE WEAKENING THROUGH THU.

THE COMBINATION OF WEAK WAA AND AN UPPER LEVEL JET COULD BRING LIGHT
SNOW TO THE AREA THU NIGHT INTO FRI MORNING. THIS IS WHERE THE
MODELS START TO DIVERGE AND IT JUST GETS WORSE WITH TIME. THE EC
KEEPS THIS PRECIP OFFSHORE WITH THE GFS INDICATING LIGHT SNOW OR
FLURRIES.

THE EC CONTINUES WITH THE IDEA OF A DIGGING TROUGH THROUGH THE
PLAINS AT THE END OF THE WEEK WITH A COASTAL STORM DEVELOPING OFF
THE SE COAST ON SAT AND LIFTING NE WHILE STRENGTHENING THROUGH SUN.
THE GFS ISN'T AS AMPLIFIED AND IS STARTING TO HINT AT A STORM OVER
THE ATLANTIC...BUT MUCH FURTHER AWAY FROM THE COAST. WILL CONTINUE
TO MONITOR THIS CLOSELY OVER THE NEXT SEVERAL DAYS.

TEMPS START OFF AT OR SLIGHTLY ABOVE NORMAL ON WED...BUT FALL WELL
BELOW SEASONABLE LEVELS WED NIGHT THROUGH THE REMAINDER OF THE
PERIOD.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH CONFIDENCE IN VFR UNTIL THE END OF THE TAF PERIOD...AS HIGH
PRESSURE OVER THE GREAT LAKES AND OHIO VALLEY BUILDS EAST AND OVER
THE AREA. LOWER VFR CIGS SHOULD ARRIVE BY LATE THIS AFTERNOON WEST
AND EARLY EVENING EAST...WITH LIGHT SNOW DEVELOPING AT THE NYC
METRO/HUDSON VALLEY TERMINALS BY ABOUT 04Z-06Z.

OUTLOOK FOR 06Z TUE THROUGH FRI...

LATE MON NIGHT...LIGHT SNOW WITH SUB-VFR CONDITIONS SPREADING NE TO
THE OTHER TERMINALS. SNOW SHOULD BEGIN TO TRANSITION TO A WINTRY MIX
AFTER ABOUT 10Z AT THE NYC METRO TERMINALS AS WARMER AIR WORKS IN
ALOFT. LOW CHANCE OF LLWS LATE AT THE NYC METRO TERMINALS DUE TO
STRONG VEERING WIND PROFILE BETWEEN 1-2 KFT AGL.

TUE...SUB-VFR CONDITIONS EXPECTED. SNOW SHOULD CHANGE TO RAIN FAIRLY
QUICKLY AT KLGA/KJFK/KISP/KGON TUES MORNING...WITH A BRIEF
INTERVENING PERIOD OF FREEZING RAIN POSSIBLE. A SOMEWHAT LONGER
PERIOD OF FREEZING RAIN IS POSSIBLE TUE MORNING AT
KEWR/KTEB/KBDR...AND A PROLONGED PERIOD OF FREEZING RAIN IS LIKELY
INTO THE AFTERNOON AT KSWF...POSSIBLY KHPN. INCREASING E-NE
WINDS...WITH G20KT POSSIBLE BY AFTERNOON AT NYC/COASTAL TERMINALS.

TUE NIGHT...SUB-VFR CONDITIONS EXPECTED. RAIN AT MOST
TERMINALS...POSSIBLY SOME LINGERING FREEZING RAIN AT KSWF.

WED...SUB-VFR CONDITIONS IMPROVING TO VFR IN THE AFTERNOON.

THU-FRI...VFR. GUSTY NW WINDS ON THU.

&&

.MARINE...
WINDS AND SEAS HAVE DIMINISHED BELOW SMALL CRAFT ADVISORY
CONDITIONS...SO CANCELED SCA FOR THE OCEAN ZONES. WINDS/SEAS WILL
CONTINUE TO DIMINISH OVERNIGHT AS HIGH PRESSURE MOVES INTO THE AREA.

AFTER A TRANQUIL START MONDAY NIGHT...WINDS INCREASE OUT THE EAST
AND SEAS BUILD LATE MONDAY NIGHT AHEAD OF THE COASTAL LOW...BUT
SHOULD REMAIN BELOW ADVISORY LEVELS THROUGH TUESDAY NIGHT.

SMALL CRAFT CONDITIONS LIKELY WED/WED NIGHT BEHIND DEEPENING STORM
SYSTEM. THERE IS EVEN THE POSSIBILITY OF GALE FORCE WIND GUSTS WED
NIGHT. SCA CONDITIONS COULD LINGER INTO THU ON PORTIONS OF THE
WATERS. TRANQUIL LATER THU THROUGH FRI AS HIGH PRES BUILDS OVER THE
AREA. SCA CONDITIONS POSSIBLE AGAIN LATE FRI NIGHT WITH A TIGHTENING
PRES GRADIENT.

&&

.HYDROLOGY...
NO PRECIPITATION IS EXPECTED THROUGH MONDAY.

SIGNIFICANT LIQUID EQUIVALENT IS EXPECTED FROM MONDAY NIGHT
THROUGH TUESDAY NIGHT...WITH AROUND AN INCH TO AN INCH AND A
QUARTER OF QPF EXPECTED.

WITH A GOOD SNOW PACK IN PLACE...MUCH OF THIS PRECIPITATION...EVEN IN
LIQUID FORM SHOULD BE ABLE TO BE RETAINED. IT WILL LIKELY TAKE AN
ADDITIONAL SIGNIFICANT QPF EVENT FOR THE RIPENING OF THE SNOW PACK
AND POTENTIAL WIDESPREAD FLOODING. IN ADDITION...INTERIOR
LOCATIONS MAY SEE A PERIOD OF FREEZING RAIN...FURTHER LESSENING
THE RUNOFF POTENTIAL. CONCERN WOULD ARISE IF MODEL GUIDANCE TRENDS
WETTER IN COMING DAYS.

FOR NOW THOUGH...IT APPEARS THAT THE THREAT IS MORE OF A MINOR
URBAN/POOR DRAINAGE TYPE...FOR AREAS RECEIVING MORE RAIN...MAINLY
NYC AND LONG ISLAND.

&&

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

&&

SYNOPSIS...KCS
NEAR TERM...KCS/PW
SHORT TERM...KCS/DW
LONG TERM...24
AVIATION...
MARINE...24/KCS
HYDROLOGY...KCS

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE NEW YORK NY
501 PM EST SUN JAN 16 2011

CTZ005>012-NJZ002-004-006-103>108-NYZ067>075-078>081-176>179-172215-
NORTHERN FAIRFIELD-NORTHERN NEW HAVEN-NORTHERN MIDDLESEX-
NORTHERN NEW LONDON-SOUTHERN FAIRFIELD-SOUTHERN NEW HAVEN-
SOUTHERN MIDDLESEX-SOUTHERN NEW LONDON-WESTERN PASSAIC-
EASTERN PASSAIC-HUDSON-WESTERN BERGEN-EASTERN BERGEN-WESTERN ESSEX-
EASTERN ESSEX-WESTERN UNION-EASTERN UNION-ORANGE-PUTNAM-ROCKLAND-
NORTHERN WESTCHESTER-SOUTHERN WESTCHESTER-NEW YORK (MANHATTAN)-BRONX-
RICHMOND (STATEN ISLAND)-KINGS (BROOKLYN)-NORTHWESTERN SUFFOLK-
NORTHEASTERN SUFFOLK-SOUTHWESTERN SUFFOLK-SOUTHEASTERN SUFFOLK-
NORTHERN QUEENS-NORTHERN NASSAU-SOUTHERN QUEENS-SOUTHERN NASSAU-
501 PM EST SUN JAN 16 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN
CONNECTICUT...NORTHEAST NEW JERSEY AND SOUTHEAST NEW YORK.

.DAY ONE...TONIGHT.

HAZARDOUS WEATHER NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

LOW PRESSURE WILL TRACK FROM NEAR THE CAROLINA COAST TUESDAY
MORNING...TO THE GULF OF MAINE BY WEDNESDAY MORNING...PASSING
SOUTHEAST OF LONG ISLAND TUESDAY NIGHT. AT THE SAME TIME...HIGH
PRESSURE WILL BE RIDGING DOWN THE SPINE OF THE APPALACHIANS MONDAY
NIGHT...THEN SLOWLY RETREATING TO THE NORTHEAST INTO LATE TUESDAY.

THE COMBINATION OF THE STORM AND THE HIGH TO HELP KEEP COLD AIR IN
PLACE NEAR THE SURFACE...A PERIOD OF SNOW IS LIKELY MONDAY NIGHT AND
EARLY TUESDAY MORNING. THE SNOW WILL LIKELY CHANGE OVER TO
FREEZING RAIN TUESDAY MORNING ACROSS THE REGION...WITH
ACCUMULATING ICE POSSIBLE ACROSS INTERIOR PORTIONS OF THE LOWER
HUDSON VALLEY AND NORTHEAST NEW JERSEY.

PRECIPITATION WILL LIKELY CHANGE TO RAIN BY TUESDAY
AFTERNOON...EXCEPT OVER THE LOWER HUDSON VALLEY WHERE FROZEN
PRECIPITATION OR SNOW MAY CONTINUE.

CURRENTLY...IT APPEARS THAT THE MOST LIKELY EVENT IS POSSIBLY AN
ADVISORY LEVEL SNOWFALL FOLLOWED BY AN ADVISORY LEVEL PERIOD OF
FREEZING RAIN. THERE IS STILL THE CHANCE THOUGH...DEPENDING ON
HOW FAST WARM AIR WORKS IN ALOFT OF EITHER A LOW END WARNING
SNOWFALL...OR WARNING LEVEL ACCRETION OF ICE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

&&

THIS HAZARDOUS WEATHER OUTLOOK PROVIDES A SUMMARY OF POTENTIAL
WIDESPREAD HAZARDOUS WEATHER EVENTS THAT MAY REACH NWS WARNING
CRITERIA. MOST LONG FUSED NWS WATCHES...WARNINGS AND ADVISORIES IN
EFFECT ARE HIGHLIGHTED.

PLEASE REFER TO THE LATEST NWS FORECASTS FOR WEATHER NOT MEETING NWS
WARNING CRITERIA.

ANZ330-335-338-340-345-350-353-355-172215-
LONG ISLAND SOUND EAST OF NEW HAVEN CT/PORT JEFFERSON NY-
LONG ISLAND SOUND WEST OF NEW HAVEN CT/PORT JEFFERSON NY-
NEW YORK HARBOR-PECONIC AND GARDINERS BAYS-
SOUTH SHORE BAYS FROM JONES INLET THROUGH SHINNECOCK BAY-
MORICHES INLET NY TO MONTAUK POINT NY OUT 20 NM-
FIRE ISLAND INLET NY TO MORICHES INLET NY OUT 20 NM-
SANDY HOOK NJ TO FIRE ISLAND INLET NY OUT 20 NM-
501 PM EST SUN JAN 16 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS.

.DAY ONE...TONIGHT.

HAZARDOUS WEATHER NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

GALE CONDITIONS WILL BE POSSIBLE WEDNESDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

&&

THIS HAZARDOUS WEATHER OUTLOOK PROVIDES A SUMMARY OF POTENTIAL
WIDESPREAD HAZARDOUS WEATHER EVENTS THAT MAY REACH NWS WARNING
CRITERIA. MOST LONG FUSED NWS WATCHES...WARNINGS AND ADVISORIES IN
EFFECT ARE HIGHLIGHTED.

PLEASE REFER TO THE LATEST NWS FORECASTS FOR WEATHER NOT MEETING NWS
WARNING CRITERIA.