FXUS61 KALY 252150
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
450 PM EST FRI DEC 25 2009
.SYNOPSIS...
A FRONT ASSOCIATED WITH A STORM SYSTEM OVER THE UPPER MIDWEST WILL
APPROACH FROM THE SOUTHWEST TONIGHT AND SATURDAY...BRINGING A WINTRY
MIX TO THE REGION...BEFORE CHANGING TO PLAIN RAIN SATURDAY NIGHT.
PRECIPITATION SHOULD END BY SUNDAY MORNING...BEFORE THE WEAKENING
REMNANT OF THE UPPER MIDWEST STORM SYSTEM BRINGS SNOW SHOWERS TO
THE REGION SUNDAY NIGHT AND MONDAY...WITH MUCH COLDER AIR RETURNING
TO THE REGION BY MONDAY NIGHT AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
...WINTER WEATHER ADVISORIES NOW EXPANDED INTO SOUTHERN VT...
...WIND ADVISORY ALSO ISSUED FOR THE CENTRAL/NORTHERN
TACONICS...SOUTHERN GREENS...AND THE BERKSHIRES FOR SAT NT...
AS OF 420 PM EST...LOW STRATUS PERSISTS ACROSS THE CAPITAL
REGION...EXTENDING NORTH INTO THE UPPER HUDSON VALLEY REGION AND
EASTERN MOHAWK RIVER VALLEY/SCHOHARIE VALLEY. IN FACT...SOME SNOW
FLURRIES/SNOW GRAINS HAVE FALLEN FROM THIS DECK AT TIMES...DESPITE
THE APPARENT LACK OF TEMPS BELOW -10C WITHIN THE CLOUD LAYER...WHICH
WOULD NORMALLY FAVOR SUPERCOOLED DROPLETS AND FREEZING DRIZZLE
RATHER THAN ICE CRYSTAL FORMATION AND SNOW. SOME FLURRIES COULD
LINGER INTO EARLY THIS EVENING...ALONG WITH THE LOW CLOUDS WITHIN
THE HUDSON VALLEY REGION...EASTERN CATSKILLS AND SCHOHARIE VALLEY
REGION.
PRECIPITATION ASSOCIATED WITH THE LEADING EDGE OF MID LEVEL WARM
ADVECTION HAS ALREADY REACHED PORTIONS OF SOUTH CENTRAL NYS/NORTHERN
PA...BUT HAS BEEN SHOWING SOME SIGNS OF WEAKENING/DRYING UPON
ENTERING THE DEEP MID LEVEL DRY LAYER. THIS FIRST BAND COULD
PRODUCE SOME LIGHT SNOW ACROSS SOUTHERN/WESTERN AREAS AFTER
SUNSET...AND POSSIBLY REACHING THE CAPITAL REGION BETWEEN 8-11
PM...ESP AS PRECIP FALLS INTO LINGERING STRATUS DECK...LEADING TO
SOME SEEDER-FEEDER PRECIP PROCESSES. A MORE ROBUST AREA OF
PRECIP...IN ASSOCIATION WITH STRONGER LOW/MID LEVEL MOISTURE
ADVECTION AND UPPER LEVEL DYNAMICS IS BLOSSOMING FROM SOUTH CENTRAL
PA INTO EASTERN VA/NC...AND THIS SHOULD GRADUALLY EXPAND NORTH
NORTHEAST TONIGHT...REACHING THE SW PORTIONS OF THE REGION AROUND
MIDNIGHT...AND AREAS FROM THE CAPITAL REGION AND POINTS N/E AFTER
MIDNIGHT...POSSIBLY HOLDING OFF ACROSS SE VT UNTIL DAYBREAK. GIVEN
FAIRLY COLD FORECAST SOUNDING TEMPERATURE PROFILES...WE EXPECT MOST
PRECIP TO BEGIN AS SNOW. IN FACT...A QUICK COATING TO ONE INCH COULD
OCCUR IN MANY VALLEY LOCALES INCLUDING THE CAPITAL REGION WELL AFTER
MIDNIGHT AS SOMEWHAT HEAVIER PRECIP DEVELOPS...WITH SOME
AREAS...MAINLY ACROSS THE EASTERN CATSKILLS/SCHOHARIE VALLEY
POSSIBLY RECEIVING 2-4 INCHES OF SNOWFALL.
AS WE APPROACH DAYBREAK...A TRANSITION TO SLEET/FREEZING RAIN IS
EXPECTED TO OCCUR ACROSS THE MID HUDSON VALLEY...NW CT...AND THE
SCHOHARIE VALLEY...EXTENDING NNW INTO THE WESTERN MOHAWK VALLEY AND
SW DACKS...WHILE SLEET MIXES WITH SNOW FURTHER N AND E INTO THE
CAPITAL REGION.
FOR MIN TEMPS...HAVE GENERALLY FOLLOWED CLOSE TO...OR EVEN A TAD
ABOVE THE WARMER MET MOS...GIVEN THE LOW CLOUDS IN PLACE ACROSS
VALLEY REGIONS...AND HIGHER LEVEL CLOUDS RAPIDLY INCREASING
ELSEWHERE. DID INDICATE COLDER MINS ACROSS PORTIONS OF SOUTHERN VT
AND THE NORTHERN BERKS...WHERE ENOUGH TRANSPARENCY IN THE HIGH
CLOUDS MAY ALLOW TEMPS TO DROP SEVERAL DEGREES THIS EVENING...BEFORE
BECOME STEADY OR EVEN RISE AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
SATURDAY/SAT NT...A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN SHOULD BE
ONGOING AT OR JUST AFTER DAYBREAK FROM THE CAPITAL REGION S AND
W...WITH MAINLY FREEZING RAIN/SLEET ACROSS THE MID HUDSON VALLEY AND
NW CT/SOUTHERN BERKS...AND MAINLY SNOW ACROSS SOUTHERN VT INTO THE
LAKE GEORGE/SARATOGA REGION AND AREAS JUST N OF THE MOHAWK RIVER.
THE PRECIP SHOULD TRANSITION TO MAINLY FREEZING RAIN/FREEZING
DRIZZLE BY MID MORNING...WITH PLAIN RAIN/DRIZZLE ACROSS THE MID
HUDSON VALLEY. GIVEN A STRONG LOW LEVEL N/NNE AGEOSTROPHIC WIND
COMPONENT OF 40-50 KT WITHIN THE 1000-900 MB LAYER...HAVE INDICATED
MAX TEMPS COLDER THAN MOST MOS GUIDANCE. THIS WILL KEEP POCKETS OF
FREEZING RAIN INTO AT LEAST THE EVENING ACROSS THE HIGHER ELEVATIONS
WITHIN THE EASTERN CATSKILLS...AND NORTHERN PORTIONS OF THE HUDSON
RIVER VALLEY/LAKE GEORGE REGION...AS WELL AS HIGHER ELEVATIONS
WITHIN EASTERN BENNINGTON CO/WESTERN WINDHAM CO. IN THESE
REGIONS...ICE ACCRETION OF UP TO...OR SLIGHTLY IN EXCESS OF ONE
THIRD OF AN INCH COULD OCCUR BY EVENING. FORTUNATELY...PRECIP
INTENSITY SHOULD REMAIN GENERALLY LIGHT...WITH SOME BREAKS IN THE
STEADY PRECIP POSSIBLE FROM LATE MORNING INTO MID AFTERNOON AS THE
STRONGER UPPER LEVEL DYNAMICS/MOISTURE ADVECTION HOLD OFF UNTIL LATE
AFTERNOON AFTER THE INITIAL BURST IN THE MORNING. E/SE WINDS WILL
ALSO INCREASE ACROSS HIGHER ELEVATIONS OF THE TACONICS/SOUTHERN
GREENS/BERKS...ESP TOWARD AND AFTER SUNSET...WELL INTO THE OVERNIGHT
HOURS. GIVEN WIND SPEEDS POTENTIALLY REACHING 45-55 KT AT 925
MB...HAVE HOISTED WIND ADVISORIES FOR THE AFOREMENTIONED
REGIONS...WHERE WINDS OF THIS DIRECTION TEND TO
FUNNEL/ENHANCE...WITH POSSIBLE GUSTS REACHING 45-55 MPH.
OTHERWISE...MOST TEMPS SHOULD RISE ABOVE FREEZING ACROSS THE REGION
ONCE MOD PRECIP DEVELOPS SAT NT...WITH PERIODS OF RAIN EXPECTED. IN
FACT...SOME ELEVATED INSTABILITY HAS BEEN NOTED IN THE NAM12...WITH
850 LI/S REACHING 0 TO -1 ACROSS EASTERN AREAS SAT EVE. THUS...A FEW
RUMBLES OF THUNDER CAN NOT BE RULED OUT IN THESE AREAS...BUT DUE TO
OVERALL LOW CHC...HAVE KEPT OUT MENTION AT THIS TIME. RAIN SHOULD
TAPER OFF IN INTENSITY FROM SW TO NE PRIOR TO DAYBREAK SUNDAY.
SUN...ANY LINGERING PRECIP SHOULD END QUICKLY SUN MORNING...WITH A
BREAK IN PRECIP EXPECTED DURING MUCH OF THE DAY. THERE IS AT LEAST A
POSSIBILTY OF SOME BREAKS IN THE CLOUDS TO DEVELOP WITHIN VALLEY
REGION...ESP SUN MORNING...BEFORE COOLING MID LEVELS ALLOW CLOUDS TO
REDEVELOP FROM THE CAPITAL REGION N AND W DURING THE MID/LATE
AFTERNOON. HOWEVER...SHOULD LOW LEVEL MOISTURE REMAIN MORE
ABUNDANT...AS THE NAM12 IMPLIES...LOW CLOUDS MAY PERSIST. SO...GIVEN
THE UNCERTAINTY...HAVE GENERALLY LEANED TOWARD MORE CLOUDS ACROSS
EASTERN AREAS...WHERE UPSLOPE W WINDS SHOULD ALLOW CLOUDS TO BE MORE
PREVALENT...WITH P SUNNY CONDITIONS WITHIN THE VALLEYS. MAX TEMPS
SHOULD REACH THE LOWER 40S WITHIN THE VALLEYS...AND 30S FOR HIGHER
ELEVATIONS...ALTHOUGH MAXES MAY OCCUR DURING THE LATE MORNING BEFORE
SLOWLY FALLING IN THE AFTERNOON WITH INTENSIFYING COLD ADVECTION.
SUN NT...POTENTIALLY INTERESTING SCENARIO DEVELOPING FOR LATE SUN
NT...AS REMNENT UPPER LEVEL LOW ASSOCIATED WITH CURRENT MIDWESTERN
SYSTEM PASSES NEAR OR SOUTH OF THE REGION. DEPENDING ON ITS
TRACK...A PORTION OF OUR REGION MAY LIE WITHIN A FAVORABLY
DEFORMATION REGION LATE AT NIGHT OR MON MORNING...ACCOMPANIED BY A
BURST OF SNOW. THIS COULD LEAD TO SOME QUICK...ALBEIT REALTIVELY
MINOR ACCUMS. THIS WILL NEED TO BE WATCHED...ESP SINCE TIMING COULD
OCCUR TOWARD OR DURING THE MON MORNING RUSH HOUR.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
WENT WITH MOS GUIDANCE...WHICH HELPS US FIT OUR GEOGRAPHICAL PUZZLE
PIECE WELL FOR TEMPS. A COLD FRONT WILL SLIDE TOWARD THE REGION
FROM SOUTH CENTRAL CANADA AT THE BEGINNING OF THE PERIOD. THIS WILL
BRING US A GOOD CHANCE OF SNOW SHOWERS...ALONG WITH STRONG WINDS AND
MUCH COLDER TEMPERATURES...AS ASSOCIATED LOW PRESSURE DEEPENS AROUND
NEWFOUNDLAND.
HIGH PRESSURE JUST BEGINS TO SETTLE IN ON TUESDAY...AS NORTHWESTERLY
WINDS WON'T SUBSIDE UNTIL TUESDAY NIGHT. WITH VERY DRY AIR
INFILTRATING THE REGION...HAVE ONLY A SLGT CHC FOR LAKE EFFECT IN
THE FAR WESTERN ADIRONDACKS TUE THRU WED.
A COMPLEX...THOUGH RELATIVELY TIMID SCENARIO EVOLVES FOR MID- TO
LATE-WEEK. A WEAK COASTAL LOW OFF CAPE HATTERAS WILL TRACK
NORTHEAST OUT TO THE SEA ACCORDING TO THE GFS. MEANWHILE...A WEAK
CLIPPER-LIKE SYSTEM WILL TRACK GENERALLY EAST ACROSS THE GREAT
LAKES...POSSIBLY TAPPING SOME MOISTURE FROM THE COASTAL LOW LATE IN
THE GAME. HOWEVER...QPFS ARE VERY LIGHT. GFS THEN LIFTS THIS LOW
NORTH INTO QUEBEC.
A COUPLE OF PRETTY COLD DAYS ARE ON TAP BEHIND THE CANADIAN FRONT...
WITH HIGHS ON TUESDAY IN ONLY THE TEENS AND 20S. DECENT SUNSHINE
WILL HELP TEMPERATURES BOUNCE BACK RATHER SWIFTLY...WITH HIGHS BY
THU AND FRI IN THE MID 20S AND 30S. TUE NIGHT WILL BE COLDEST...
WITH ALMOST ALL LOCATIONS DOWN INTO THE SINGLE DIGITS...MAINLY BELOW
ZERO IN THE ADIRONDACKS. BY THURSDAY NIGHT...MOST LOWS WILL BE DOWN
ONLY INTO THE TEENS.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
A COMPLEX STORM APPROACHING THE NORTHEAST WILL BRING MIXED PRECIP
OVERNIGHT...TRANSITIONING TO MAINLY RAIN SATURDAY AFTERNOON. THE
ONSET OF PRECIP WILL MOVE SOUTH TO NORTH STARTING AROUND 00Z AT KPOU.
AT PRESENT...STRONG INVERSION KEEPING DECK OF LOW STRATUS IN THE
VALLEY WITH LIGHT NORTHEAST WINDS. NAM MODEL KEEPING ATMOSPHERE
COLDER TONIGHT...WHICH COULD LEAD TO MORE SNPL THAN -FZRAPL.
HOWEVER CONFIDENCE IN THIS MODEL IS LOW AS 12Z RAOB SOUNDINGS IN
WESTERN NY...WESTERN PA AND OHIO INDICATE VERY WARM AIR
ALOFT...INCLUDING A WARM NOSE UP TO 9C.
KGFL...IFR STRATUS IMPROVING THIS AFTERNOON TO MVFR. AS SYSTEM
APPROACHES...IFR CIGS WILL DEVELOP AFTER MIDNIGHT WITH VCSH
STARTING AS MIX OF -SNPL. VSBYS WILL ALSO DETERIORATE TO MVFR
WITH THE ONSET OF -FZRAPL AROUND 07Z. PRECIP WILL TRANSITION TO
ALL -FZRA AROUND 10Z...FURTHER TRANSITIONING TO ALL RAIN AROUND
18Z. WINDS WILL BE LIGHT OUT OF THE NORTH TO NORTHEAST THROUGHOUT
THE PERIOD.
KALB...STILL THE WORST CONDITIONS OF ALL THE TERMINALS THIS
AFTERNOON WITH LIFR CIGS. LOW STRATUS SLOWLY ERODING AWAY BUT
HIGH CIRRUS INCREASING WHICH WILL DEFLECT THE SUN/S ABILITY TO
CONTINUE ERODING LOW STRATUS DECK. EXPECT LIFR CIGS TO IMPROVE TO
IFR AT BEST THIS AFTERNOON...FURTHER IMPROVING TO MVFR CIGS AND
VFR VSBYS THIS EVENING. VSBYS WILL DETERIORATE TO MVFR WITH THE
ONSET OF -FZRAPL AROUND 05Z. CONDITIONS WILL FURTHER DETERIORATE
TO IFR AT 10Z AS -FZRAPL TRANSITIONS TO -FZRA. THE -FZRA WILL
CONTINUE THROUGH THE MORNING...TRANSITIONING TO -RA AFTER 15Z.
KPOU...VFR CONDITIONS THIS AFTERNOON WILL HAVE PERIODS OF MVFR
CIGS THROUGH 20Z. MVFR VSBYS EXPECTED WITH VCSH STARTING AROUND
00Z. -FZRA EXPECTED AROUND 02Z WITH CONDITIONS CONTINUING TO
DETERIORATE WITH IFR CIGS. FZRA WILL TRANSITION TO RA AROUND 15Z.
OUTLOOK...
SAT NGT...MVFR-IFR...RAIN TRANSITIONING TO A MIX OF RA AND PL AROUND
03Z AT KGFL/KALB.
SUN...VFR...MVFR POSSIBLE WITH CHC -SHRA/-SHSN.
MON...VFR...MVFR POSSIBLE WITH CHC -SHSN.
TUE-WED...VFR...NO SIG WX.
&&
.HYDROLOGY...
A WINTRY MIX OF SNOW...SLEET AND FREEZING RAIN IS EXPECTED TO START
LATE THIS EVENING AND TRANSITION TO FREEZING RAIN LATE TONIGHT INTO
SATURDAY MORNING AND THEN EVENTUALLY RAIN SATURDAY AFTERNOON INTO
SATURDAY EVENING. THE TRANSITION TO RAIN WILL BE QUICKER FARTHER
SOUTH...MAINLY ACROSS THE MIDDLE AND LOWER HOUSATONIC BASIN...THE
RONDOUT CREEK...WAPPINGERS CREEK...AND ESOPUS CREEK AND IN THESE
AREAS QPF AMOUNTS MAY LOCALLY EXCEED 1 INCH WHICH MAY RESULT IN
RISES OF SEVERAL FEET. AT THIS TIME IT DOES NOT APPEAR THAT THERE
WILL BE ENOUGH RUNOFF FOR FLOODING.
ACROSS THE REMAINDER OF THE HSA...THE RUNOFF WILL BE LESS AS SOME
SNOW COVER WILL ABSORB SOME OF THE RUNOFF...AND ANY RUNOFF THAT DOES
OCCUR WILL BE LESS DUE TO COLDER TEMPERATURES ON SATURDAY.
AFTER THE SYSTEM WINDS DOWN ON SUNDAY...IT WILL BE MAINLY DRY INTO
EARLY NEXT WEEK. IT WILL TURN COLDER SO THAT PRECIPITATION SHOULD
COME AS SNOW. TEMPERATURES ARE FORECAST TO DROP BELOW FREEZING
SUNDAY NIGHT AND REMAIN BELOW FREEZING IN MOST AREAS THROUGH AT
LEAST THE MIDDLE OF NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO NOON EST
SATURDAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST
SATURDAY FOR NYZ038>041-043-047>054-058-063-083-084.
FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO NOON EST
SATURDAY FOR NYZ059>061-064>066.
WIND ADVISORY FROM 6 PM SATURDAY TO 6 AM EST SUNDAY FOR NYZ054-
061-084.
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 6 AM EST
SUNDAY FOR NYZ032-033-042-082.
MA...FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST
SATURDAY FOR MAZ001-025.
WIND ADVISORY FROM 6 PM SATURDAY TO 6 AM EST SUNDAY FOR MAZ001-
025.
VT...WIND ADVISORY FROM 6 PM SATURDAY TO 6 AM EST SUNDAY FOR VTZ013-
014.
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 6 AM EST
SUNDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...KL
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...ELH
AVIATION...KGS
HYDROLOGY...11
