FXUS61 KOKX 232253 CCA
AFDOKX
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NEW YORK NY
551 PM EST WED DEC 23 2009
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL SKIRT THE AREA INTO THIS
EVENING...FOLLOWED BY HIGH PRESSURE BUILDING SOUTHEAST FROM
ONTARIO LATER TONIGHT INTO CHRISTMAS EVE. THE HIGH WILL SHIFT EAST
ON CHRISTMAS DAY...ALLOWING A FRONTAL SYSTEM TO APPROACH FROM THE
WEST. THIS FRONTAL SYSTEM...COMBINED WITH COLD AIR LOCKED IN
PLACE EAST OF THE APPALACHIANS...COULD CREATE ICY CONDITIONS FOR
INTERIOR SECTIONS CHRISTMAS NIGHT INTO SATURDAY MORNING...AND
HEAVY RAIN THROUGHOUT THE TRI-STATE AREA ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
BAND OF MODERATE SNOW TO THE NORTH...STRETCHING FROM UTICA TO JUST
SOUTH OF ALBANY AND JUST NORTH OF DUTCHESS COUNTY...HAS REMAINED
MOSTLY TO THE NORTH...WITH POSSIBLE SOME FLURRIES DROPPING INTO
THE LOWER HUDSON VALLEY AND SW CT AS EXPECTED. STILL MUST KEEP AN
EYE ON THIS BAND AS THE ASSOCIATED MOISTURE AND FORCING (H7
FRONTOGENESIS AND STRONG MID LEVEL SHORTWAVE) WILL MOVE SE INTO
THE AREA IN A WEAKENED STATE AS THE PARENT UPPER LOW MOVES SE OFF
THE NEW ENGLAND COAST. WILL MONITOR THIS BAND AS IT MOVES SE...AT
WORST IT APPEARS THAT IT COULD PRODUCE A COATING OF SNOW OVER SOME
SPOTS IN THE LOWER HUDSON VALLEY AND SW CT THIS EVENING. LOWS
TONIGHT SHOULD BE IN THE 20S NYC/IMMEDIATE COASTAL SECTIONS...AND
TEENS INLAND AND LONG ISLAND PINE BARRENS. WINDS IN THE WAKE OF
THE AFOREMENTIONED DISTURBANCE SHOULD REMAIN UP OVERNIGHT...SO DO
NOT EXPECT WINDS TO DECOUPLE AND PROMOTE RAPID RADIATIONAL COOLING
OVER SNOW PACK AS OCCURRED DID LAST NIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
HIGH PRESSURE MOVES OVER THE AREA SFC AND ALOFT ON THU...WITH
MILDER TEMPS IN THE MID/UPPER 30S BUT STILL RUNNING A LITTLE UNDER
MAV GUIDANCE. SURFACE FLOW STILL EXPECTED TO TURN EASTERLY THU
NIGHT AT THE COAST AND NE OVER THE INTERIOR VIA COLD AIR
DAMMING...WITH LOW LEVEL MOISTENING OVER SNOW PACK POSSIBLY
LEADING TO FOG AND/OR LOW STRATUS LATE THU NIGHT INTO CHRISTMAS
MORNING...AND A CHANCE OF LIGHT RAIN OR DRIZZLE IN THE AFTERNOON.
WITH TEMPS BELOW FREEZING IN MOST SPOTS INITIALLY...IF FOG DOES
OCCUR RIMING ON SURFACES WOULD ALSO BE LIKELY...WHICH COULD
PRODUCE HAZARDOUS DRIVING CONDITIONS LATE THU NIGHT INTO CHRISTMAS
MORNING. TEMPS NOT EXPECTED TO RISE MUCH OVER THE INTERIOR...SO
ICING FROM ANY SPOTTY LIGHT PRECIP COULD REMAIN A PROBLEM WELL
NORTH/WEST OF NYC IN THE AFTERNOON.
HAVE CONTINUED WITH A NAM/GFS BLEND RE TIMING OF STEADIER RAINS
WITH APPROACHING FRONTAL SYSTEM CHRISTMAS NIGHT INTO SAT. COLD AIR
DAMMING SHOULD PROMOTE NE FLOW INLAND...WITH STRENGTHENING E FLOW
AT THE COAST...SO FREEZING RAIN IS EXPECTED NORTH/WEST OF NYC AND
ACROSS SOUTHERN CT...POSSIBLY ALL THE WAY TO THE CT COAST.
NAM/GFS/ECMWF BLEND OF QPF SUGGESTS MAINLY AN ADVISORY EVENT...BUT
CANNOT RULE OUT AREAS OF 1/2 INCH ACCRETION...PARTICULARLY IN
ORANGE COUNTY. IS IT TOO EARLY FOR ANY WATCHES/ADVISORIES...SO
WILL CONTINUE TO MENTION IN HWO AND HIGHLIGHT ON MAIN WEB PAGE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE SECONDARY LOW FROM THIS STORM IS FORECAST TO MOVE OVER OR
NEARBY THE CWA SATURDAY NIGHT INTO SUNDAY MORNING. TEMPERATURES
ALOFT WOULD SUPPORT RAIN THROUGH THE TIME WHEN PRECIPITATION ENDS
FROM WEST TO EAST. WITH A WEAKENING HIGH TO THE NE...SURFACE
TEMPERATURES LIKELY WILL NOT DROP UNTIL THE PRECIPITATION ENDS. SO
GIVEN FORECAST TEMPS RISING ABOVE FREEZING ACROSS THE CWA DURING
THE DAY ON SATURDAY... WILL GO WITH PLAIN RAIN AS PRECIP TYPE
SATURDAY NIGHT.
FOR SUNDAY MORNING...JUST A CHANCE FOR LINGERING RAINFALL ACROSS
EASTERN ZONES...AND SLIGHT CHC ELSEWHERE...OTHERWISE DRY FOR THE REST
OF THE DAY AS AN H5 LOW CENTER MOVES THROUGH THE OHIO VALLEY.
H5 LOW CENTER PROBABLY PASSES THROUGH MONDAY MORNING WITH A SLIGHT
CHANCE OF SNOW SHOWERS OR FLURRIES. LOW PRESSURE IN SE CANADA
DEEPENS THROUGH THE DAY WHILE HIGH PRESSURE BUILDS IN FROM THE WEST.
THE RESULTANT TIGHT PRESSURE GRADIENT WOULD RESULT IN INCREASING
WINDS THROUGH THE DAY WITH HIGH TEMPERATURES AT OR SLIGHTLY BELOW
NORMAL.
A SHOT OF EVEN COLDER AIR IS FORECAST BEHIND A COLD FRONT DROPPING
DOWN OUT OF CANADA LATE MONDAY NIGHT INTO TUESDAY MORNING. AGAIN...A
SLIGHT CHANCE OF SNOW SHOWERS OR FLURRIES DURING THIS TIME. WITH 850
MB TEMPS FALLING TO AROUND -12C...HIGHS ONLY IN THE MID 30S EXPECTED
ON TUESDAY. HIGH PRESSURE THEN DOMINATES THE WEATHER THROUGH THE REST
OF THE LONG TERM WITH DRY WEATHER.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
UPPER LEVEL DISTURBANCE TO OUR NORTH WILL BRING SOME SCATTERED
CLOUDS AROUND 3KFT TO THE AREA TERMINALS THIS AFTERNOON. THERE MAY
BE A FEW LOCATIONS THAT GO BROKEN FOR A BRIEF PERIOD...HOWEVER
CONFIDENCE IS NOT HIGH ENOUGH TO KEEP IN THE TAFS. OTHERWISE...CLEAR
SKIES RETURN TONIGHT AND THURSDAY.
GUSTY WNW WINDS CONTINUE THROUGH EARLY EVENING. THE GUSTS ENDS THE
EVENING...WITH SUSTAINED WINDS BELOW 10 KT AFTER MIDNIGHT.
TAF COMMENTS (FORECASTER INSIGHT ON TIMING, CONFIDENCE, TRENDS AND GROUND OPS)
KEWR...WINDS WILL BE ON EITHER SIDE OF 310 THROUGH MUCH OF
THE DAY TODAY. BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KEWR HOURLY WIND FORECAST
ALL WIND DIRECTIONS ARE TRUE...ADD 13 DEGREES FOR MAGNETIC
23/16Z 29013G21KT
23/17Z 29015G23KT
23/18Z 30015G23KT
23/19Z 30015G23KT
23/20Z 31015G23KT
23/21Z 31014G22KT
23/22Z 31014G22KT
23/23Z 32013G21KT
24/00Z 32013G21KT
24/01Z 32013G21KT
24/02Z 32012G21KT
24/03Z 32012G22KT
KJFK...BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KLGA...WINDS WILL BE ON EITHER SIDE OF 310 THROUGH MUCH OF
THE DAY TODAY. BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KTEB...WINDS WILL BE ON EITHER SIDE OF 310 THROUGH MUCH OF
THE DAY TODAY. BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KHPN...WINDS WILL BE ON EITHER SIDE OF 310 THROUGH MUCH OF
THE DAY TODAY. BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KSWF...BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KISP...BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KBDR...BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
KGON...BROKEN CIGS AROUND 3000 FT POSSIBLE FOR AN HOUR OR
TWO THIS AFTERNOON.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
THURSDAY...VFR.
THURSDAY NIGHT-FRIDAY...SUB-VFR POSSIBLE WITH LOW CLOUDS AND/OR
FOG. -FZRA OR -FZDZ ALSO POSSIBLE INLAND FRI AFTERNOON
(KHPN/KSWF).
FRIDAY NIGHT-SATURDAY NIGHT...SUB VFR. FZRA POSSIBLE
INTO SAT MORNING FOR KSWF/KHPN...OTHERWISE WINTRY MIX/RAIN
BECOMING ALL RAIN FRIDAY NIGHT (LOWEST CHANCE OF MIX
KLGA/KJFK/KEWR). GUSTY ENE-E WINDS FRI NIGHT BECOMING SE
SATURDAY...THEN S SATURDAY NIGHT. LLWS ALSO POSSIBLE.
SUNDAY...RAIN LIKELY TAPERING OFF FROM W-E EARLY SUNDAY
MORNING...WITH VFR RETURNING.
&&
.MARINE...
SCA CONDITIONS WILL PERSIST OVER THE OCEAN THROUGH THU...AND ON
THE EASTERN SOUND/BAYS THROUGH TONIGHT...WITH GUSTS UP TO 25 KT AND
OCEAN SEAS UP TO 6 FT...A FOOT ABOVE WAVEWATCH.
MARGINAL SCA CONDITIONS POSSIBLE FRI ON THE OCEAN VIA
STRENGTHENING EASTERLY FLOW...AND ON ALL WATERS BY SAT. A DECENT
CHANCE OF GALES ON THE OCEAN WATERS SATURDAY AFTERNOON/EVENING
AHEAD OF LOW PRESSURE PASSING OVER OR NEAR THE AREA...OTHERWISE
SCA CONDITIONS ACROSS ALL WATERS...WITH WINDS SUBSIDING THROUGH
THE NIGHT. SCA CONDITIONS BECOME POSSIBLE ONCE AGAIN DURING SUNDAY
AFTERNOON AS THE PRESSURE GRADIENT RE-TIGHTENS. GALES THEN BECOME
POSSIBLE MONDAY AFTERNOON ACROSS THE OCEAN WATERS AND
EASTERN SOUND.
&&
.HYDROLOGY...
SNOW PACK HAS COMPACTED SOMEWHAT...BUT WITH LITTLE IF ANY RUNOFF
OCCURRING AS MAX TEMPS HAVE RISEN NO HIGHER THAN THE 30S.
POTENTIAL EXISTS FOR AN INCH OR MORE OF LIQUID EQUIVALENT QPF...
MAINLY LATE FRI NIGHT THROUGH SUN MORNING...ON TOP OF SNOW PACK
WITH ABOUT 1-2 INCHES WATER EQUIVALENT IN MOST PLACES...LESSER
NORTH/WEST OF NYC. THIS COULD LEAD TO BOTH URBAN AND SMALL
RIVER/STREAM FLOODING SAT INTO SUN...DEPENDING ON SPEED OF SNOW
MELT AND DURATION OF HEAVIER RAIN.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR ANZ350-353-
355.
SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ330-340.
&&
$$
SYNOPSIS...BG
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JC
AVIATION...BC
MARINE...BG/JC
HYDROLOGY...BG/JC
