FXUS61 KOKX 120106
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
806 PM EST FRI DEC 11 2009
.SYNOPSIS...
WINDS DIMINISH TONIGHT AS HIGH PRESSURE BUILDS INTO THE AREA. SUNNY
AND SLIGHTLY WARMER ON SATURDAY. LOW PRESSURE MOVES UP THE ATLANTIC
COAST SUNDAY BRINGING RAIN AND PERHAPS SNOW AT THE ONSET ACROSS THE
INTERIOR. WINDY AND COLDER WEATHER ARE FORECAST FOR EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
WINDS SUBSIDE TONIGHT AS HIGH PRESSURE BUILDS INTO THE REGION AND
THE PRESSURE GRADIENT RELAXES. DIURNAL CU WANES WITH THE LOSS OF
SUNSHINE HOWEVER WINDS WILL PREVENT AREAS FROM BOTTOMING OUT MUCH
BELOW 20F SAVE FOR THE INTERIOR. LOWEST WIND CHILL VALUES WILL
BE IN THE SINGLE DIGITS TO MIDDLE TEENS TONIGHT. BENIGN WEATHER
SATURDAY WITH A SURFACE ANTI-CYCLONE NEARBY. H8 TEMPS CLIMB ABOUT
8C SO DESPITE NORTHERLY COLD ADVECTION...MAXT SHOULD BE ONE TO TWO
CATEGORIES HIGHER. MID AND HIGH CLOUDS INCREASE DURING THE LATE
AFTERNOON HOURS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
DRY WEATHER SATURDAY NIGHT WITH INCREASING MOISTURE FROM THE
SOUTHWEST AHEAD OF THE NEXT CYCLONE. 12Z NCEP SUITE CONTINUES TO
DIFFER WITH THE SPEED OF THE SYSTEM MOVING UP THE EAST COAST...GFS
ENSEMBLES OFFER A NICE COMPROMISE BETWEEN THE FASTER ECMWF AND
SLOWER NAM. EITHER CASE...ALL MODELS ARE WARMER IN THE BOUNDARY
LAYER THAN PREVIOUS RUNS. WITH A LATER PCPN ONSET TIME /LATE SUN
MORNING/...PTYPE MAY NOT BE AN ISSUE. SOUNDINGS ACROSS THE HIGHER
ELEVATIONS IN ORANGE AND PUTNAM COUNTIES REVEAL ALL LIQUID
PTYPE. NONETHELESS...THIS WILL NEED TO BE WATCHED SINCE MODELS
HAVE A SLOW BIAS WITH WARM ADVECTION PCPN. THUS...A WINTRY MIX AT
THE ONSET IS STILL POSSIBLE IN THE AFOREMENTIONED LOCATIONS.
HIGH CONFIDENCE FORECAST FOR NYC AND POINTS E SUNDAY. MEDIUM
CONFIDENCE IN THE HIGHER TERRAIN OF NE NJ AND THE LOWER HUDSON
VALLEY FOR PTYPE SUN.
CARRIED CATEGORICAL POPS THROUGH MOST OF SUNDAY NIGHT WITH NUMBERS
DROPPING OFF TOWARD DAWN MONDAY. NAM/GFS BOTH HINT AT 7.0CKM-1
LAPSE RATES AND THE LOWEST TROPOPAUSE HEIGHTS CROSSING NYC AND LONG
ISLAND SUN AFTERNOON / EVENING WHICH WOULD WARRANT HIGHER RAINFALL
TOTALS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
MAIN FOCUS IN THE EXTENDED IS ON THE MIDWEEK PERIOD.
LOW PRES WILL BE ABOUT 300MI E OF KMTP BY 12Z MON. 12Z GFS/ECMWF/NAM
ARE IN AGREEMENT WITH THIS. THIS WILL RESULT IN AN END TO PCPN
AROUND SUNRISE AND DECREASING CLOUDS DURING THE DAY. UPR LVL RIDGING
WILL RESULT IN H85 TEMPS IN THE 3-5C RANGE. MIXING WILL BE LIMITED
HOWEVER DUE TO LGT N FLOW IN THE WAKE OF THE LOW SO HIGHS IN THE 40S
FCST. WAA ALOFT ON SW FLOW WILL ALLOW FOR INCREASING CLOUDS MON NGT.
A THE SAME TIME...STRONG SHRTWV AT H5 WILL BE DRAWING A CDFNT
TOWARDS THE CWA. LGT PCPN IS POSSIBLE IN THE WAA REGIME...AND WITH A
DRY START TO THE EVE TEMPS MAY DROP TO BLW 32 ACROSS NRN PORTIONS OF
THE LWR HUDSON VALLEY. THIS WOULD SET THE STAGE FOR SPOTTY -FZRA
ACROSS THOSE AREAS. ELSWHERE...-RA WOULD BE THE PTYPE.
CDFNT SWEEPS THE SUBTROPICAL MOISTURE OFFSHORE TUE WITH A BAND OF RA
POSSIBLE WITH THE FROPA. BOTH THE 12Z GFS/ECMWF PHASE THE SRN AND
NRN STREAM SYSTEMS AND DEVELOP A DEEP LOW NE OF THE CWA TUE NGT AND
WED. PREV RUNS HAVE HINTED AT THIS SCENARIO AS WELL. THE
PLACEMENT/DEPTH/TIMING OF THE SYSTEM HAVE YET TO BE FULLY RESOLVED.
THE FCST FOLLOWS A SOLN WHICH DEVELOPS A MODEST 980-985 LOW INVOF
THE MARITIMES. IMPACT TO THE CWA WOULD BE SHSN AS THE STORM
INTENSIFIES NE OF THE CWA WED MRNG WITH STRONG WINDS...CLOSE TO ADVY
CRITERIA...WED AND THU. SECONDARY ARCTIC FRONT WED MAY ASSIST IN
SHSN DEVELOPMENT.
THIS SYSTEM BEARS WATCHING AS SOME RUNS HAVE INDICATED DEVELOPMENT
FURTHER S WHICH WOULD BE CONDUCIVE TO A BAND OF SN ON THE BACK SIDE
OF THE LOW...AND SOME RUNS HAVE INDICATED PRESSURES DROPPING INTO
THE 960S ACROSS CANADA WHICH WOULD RESULT IN A HIGH WIND EVENT
ACROSS THE CWA.
TEMPS WILL FALL INTO THE 30S WED WITH A COLD AMS REMAINING IN PLACE
THRU FRI. ALTHO AN ISOLATED SHSN MAY STRAY INTO PORTIONS OF THE
HUDSON VALLEY...THE THU AND FRI FCST IS DRY.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
VFR THROUGH PERIOD.
GUSTS DIMINISH OUTSIDE CITY TERMINALS LATE TONIGHT...RETURNING
AFTER DAYBREAK FOR ALL TERMINALS ON SAT. WINDS DIMINISH LATE SAT
INTO SAT NIGHT AS HIGH BUILDS IN.
OUTLOOK 00Z SUN THROUGH TUE...
SAT NIGHT...VFR.
SUN-SUN NGT...SUB-VFR POSSIBLE SUN AFTERNOON/EVENING...WITH
CHANCE OF MIXED PRECIP CHANGING TO RAIN AT THE COAST...AND SNOW
CHANGING TO RAIN OR MIXED PRECIP INTERIOR.
MON...VFR.
TUE...SUB-VFR POSSIBLE WITH COLD FROPA.
&&
.MARINE...
THE CLOSE PROXIMITY OF LOW PRESSURE OVER SOUTHEAST CANADA AND HIGH
PRESSURE OVER THE SOUTH CENTRAL U.S. WILL CONTINUE WEST GALES
ACROSS OCEAN WATERS AND EASTERN LI SOUND THROUGH TONIGHT. FOR
WESTERN L.I. SOUND AND NY HARBOR WINDS/WAVES WILL REMAIN ABOVE SCA
THROUGH THE NIGHT. BOTH HAZARDS MAY NEED TO BE EXTENDED INTO THE
MORNING HOURS...BUT DO NOT HAVE HIGH ENOUGH CONFIDENCE TO DO SO AT
THIS TIME. WINDS CONTINUE TO DECREASE SATURDAY AS HIGH PRESSURE PASSES
CLOSE BY. WAVES REMAIN ABOVE FIVE FEET ON THE OCEAN SATURDAY...SO
SCA FOR HAZARDOUS SEAS IS LIKELY.
WINDS INCREASE SUNDAY AS LOW PRESSURE MOVES UP THE ATLANTIC COAST.
SCA CRITERIA COULD BE ACHIEVED FOR WINDS...ESPECIALLY IN WAKE OF
LOW PRESSURE SUNDAY NIGHT INTO MONDAY.
WILL CANCEL THE LOW WATER ADVISORY AS NO CONCERNS HAVE BEEN
REPORTED. TIDAL DEPARTURES ON THE NEXT LOW TIDE CYCLE ARE NEARLY
EQUAL TO THE PREVIOUS ONE...SO DO NOT EXPECT ANY ISSUES.
LOW PRES ABOUT 260NM E OF MONTAUK MON MRNG WILL QUICKLY TRACK EWD
DURING THE DAY. LINGERING SCA SEAS ON THE OCEAN WILL SUBSIDE BY EVE.
ALL OTHER AREAS WILL BE IN LGT N FLOW WITH WINDS BLW SCA LVLS. SW
FLOW WILL INCREASE AHEAD OF A CDFNT ON TUE. SW WINDS MAY APPROACH
MRGNL SCA LVLS ON THE OCEAN. THE CDFNT WILL TRACK THRU THE CSTL
WATERS TUE AFTN AND EVE WITH LOW PRES DEVELOPING NE OF THE WATERS.
THIS WILL SET THE STAGE FOR A PERIOD OF STRONG WINDS AND HAZARDOUS
SEAS THRU THU. GALES APPEAR LIKELY ATTM.
&&
.HYDROLOGY...
DRY WEATHER THROUGH SAT NIGHT WILL ALLOW ANY RIVERS/STREAMS TO
RECEDE. RAINFALL BETWEEN 1/2 TO 3/4 OF AN INCH IS POSSIBLE FOR NYC
AND LONG ISLAND SUNDAY AFTERNOON/NIGHT...WITH 1/4 TO 1/2 INCH LIQUID
EQUIVALENT QPF FARTHER NORTH AND WEST.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ335-338-
340-345.
GALE WARNING UNTIL 6 AM EST SATURDAY FOR ANZ330-350-353-355.
&&
$$
