FXUS61 KALY 252133
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
433 PM EST WED NOV 25 2009

.SYNOPSIS...
AN OCCLUDED FRONT WILL MOVE ACROSS THE REGION TONIGHT 
BRINGING A CHANCE OF SHOWERS.  WEAK HIGH PRESSURE WILL BE OVER THE 
REGION ON THANKSGIVING WITH MILD...CLOUDY...AND DRY CONDITIONS.  A 
COMPLEX STORM SYSTEM WILL IMPACT THE NORTHEAST THURSDAY NIGHT 
THROUGH FRIDAY NIGHT WITH UNSETTLED WEATHER INCLUDING RAIN...SOME 
SNOW...ESPECIALLY FOR THE HIGHER ELEVATIONS NORTH AND EAST OF THE 
MOHAWK RIVER VALLEY...AND BLUSTERY WINDS.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 300 PM EST...SFC LOW PRESSURE CONTINUES TO DRIFT INTO THE
NRN GREAT LAKES REGION WITH THE RUC13 SHOWING A SHORTWAVE TIED TO
AN OCCLUDED FRONT FOCUSING MULTIPLE BANDS OF SHOWERS OVER NW
PA...AND W-CNRL NY...VIA THE REGIONAL MOSAIC RADAR. SOME OF THESE
SCT SHOWERS WITH THE OCCLUDED BOUNDARY WILL MOVE INTO THE REGION
OVERNIGHT. WE BELIEVE THE BEST CHANCE OF SHOWERS WILL BE FROM THE
CAPITAL REGION...AND ERN CATSKILLS NORTH AND WEST. WE PLACED SOME
LIKELY POPS IN WEST OF THE HUDSON RIVER VALLEY. THE AIR MASS IS
FAIRLY MOIST...AND MILD FOR LATE NOVEMBER. WE KEPT SOME PATCHY FOG
IN EVERYWHERE AFTER MIDNIGHT WITH SOME LINGERING ISOLD-SCT
SHOWERS. MIN TEMPS WILL BE MILD IN THE MID 30S TO L40S.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THANKSGIVING WILL BE THE QUIET BEFORE THE COMPLEX STORM TO FOLLOW
THE NEXT FEW PERIODS. THE SOUNDINGS AND RH PROFILES ARE MOIST
PRIOR TO NOONTIME. WE COULD SEE A FEW BREAKS OF SUN...IF ENOUGH
SUBSIDENCE IS REALIZED BY THE WEAK BUBBLE SFC HIGH THAT NOSES IN
FROM NORTHEAST NJ...AND PA...AS A COASTAL/OCEAN LOW WELL EAST OF
THE MID ATLANTIC REGION SLOWLY LIFTS NORTHWARD. MEANWHILE...A STRONG 
UPPER LEVEL LOW ASSOCIATED WITH THE HIGH AMPLITUDE LONG WAVE
NEUTRAL TILTED UPPER TROUGH MIGRATES CLOSER FROM THE LOWER GREAT
LAKES REGION. THE FCST AREA WILL BE IN THE NULL ZONE BETWEEN
SYSTEMS DURING THE DAY. TEMPS WILL BE VERY MILD FOR THE HOLIDAY
WITH HIGHS IN THE U40S TO MID 50S. H850 TEMPS WILL BE ABOVE
NORMAL IN THE 0-5C RANGE. MAX TEMPS WILL BE AROUND 10 DEGREES OR
SO ABOVE NORMAL.

THANKSGIVING NIGHT...THE DETERMINISTIC MODELS AND ENSEMBLES
DIVERGE HERE ON HOW TO HANDLE THE COASTAL SYSTEM WITH THE UPSTREAM
CLOSED/CUTOFF UPPER LOW. SOME PCPN GENERATED BY WEAK ISENTROPIC
LIFT OF THE UPSTREAM LOW AND ITS OCCLUDED FRONT WILL BE
APPROACHING FROM THE SOUTH AND WEST...WHILE LIFT GENERATED BY THE
SFC WAVE SE OF CAPE COD WILL FOCUS MORE LIGHT RAIN MOVING N/NE.
THE UPPER DYNAMICS INDICATE POTENTIAL PHASING WILL OCCUR BETWEEN
THE TROUGHS...HOWEVER...THE 12Z GLOBAL ENSEMBLE MEAN INDICATES
A STRONG CLUSTERING OF THE MEMBERS NEAR CAPE COD BY 12Z FRI. THE
NAM/CAN REG DISAGREES WITH THE GFS/ECMWF/ENSEMBLES SCENARIO. THE
MAIN PTYPE DURING THIS TIME LOOKS TO BE LIGHT RAIN WITH THE LOW
LEVELS QUITE WARM...AND THE 0C ISOTHERM AT H850 JUST EAST OF KUCA.
EXPECT LOWS TO BE IN THE MID30S TO L40S.  THE EVOLUTION OF WHAT
GOES ON FRI-FRI NIGHT IS WHERE THINGS BECOME VERY COMPLICATED.

FRIDAY/FRIDAY NIGHT...CYCLOGENESIS CONTINUES IN THE VICINITY OF THE
GULF OF MAINE WITH A 980-985 HPA LOW BY THE EARLY PM. THE
PLACEMENT OF THE H500 CLOSED CIRCULATION IS CRITICAL FOR WHERE
SNOW LEVELS FALL DURING THE DAY...AND WHERE THE LOW/MID LEVEL
DEFORMATION OCCURS. WE ARE LEANING TOWARDS AN HPC/GFS/GEFS
SCENARIO. THE GFS PLUME FOR KALB AT 06Z HAD MORE CONSISTENCY THAN
THE 12Z...WHERE THE MAIN QPF IS AROUND AN INCH FOR THE EVENT. THE
COLD CONVEYOR BELT KICKS IN WITH THE ECMWF/GFS SHOWING POTENTIALLY
A HALF AN INCH TO AN INCH PLUS OF QPF THAT COULD BE TRANSITIONING
TO SNOW ESPECIALLY FOR SRN VT....AND NORTH OF THE MOHAWK RIVER
VALLEY. THERE IS QUITE A BIT OF UNCERTAINTY IN THE AMOUNT OF QPF
AND TRACK OF THE SYSTEM. WHAT IS CERTAIN...IS THAT AN IMPRESSIVE
LOW LEVEL PRESSURE GRADIENT SETS UP BETWEEN THE COASTAL LOW...AND
SFC HIGH PRESSURE NEAR THE LOWER MS RIVER VALLEY. THE WINDS WILL
INCREASE OUT OF THE W/NW LATE FRI PM...AND STRENGTHENS OVERNIGHT.
WE COULD RECEIVE WIND GUSTS APPROACHING LOW END ADVISORY
LEVEL...AS THE H850 WINDS INCREASE TO 45-60 KTS. WE WILL CONTINUE
TO CONVEY THE POTENTIAL HAZARDS IN THE HWO PRODUCT.

IN TERMS OF THE PCPN...WE HAVE FOLLOWED CLOSE TO HPC. THE BEST
CHANCE FOR A LIGHT TO MODERATE SNOWFALL IN OUR PRESENT ASSESSMENT
WOULD BE ACROSS THE SRN ADIRONDACKS...SRN GREENS...NRN BERKS...AND
PERHAPS THE LAKE GEORGE REGION...ESPECIALLY IN THE OVERNIGHT
PERIOD...AS A SUB SYNOPTIC UPSLOPE EVENT MAY MATERIALIZE DURING
THE LATE PM THRU THE OVERNIGHT TIME FRAME. MOST LOCATIONS WILL
LIKELY SEE SCT SNOW SHOWERS BY SATURDAY MORNING.

SATURDAY...THE LOW BECOMES STACKED AND OCCLUDES NEAR NEW
BRUNSWICK/GULF OF MAINE. IMPRESSIVE LOW LEVEL WIND FIELDS WILL
STILL IMPACT THE REGION. ENOUGH SUBSIDENCE/DOWN SLOPING WILL ALLOW
SOME AFTERNOON SUNSHINE.  BLUSTERY AND COLD CONDITIONS WILL
PREVAIL WITH LINGERING UPSLOPE SNOWS TIL NOONTIME OVER THE SRN
DACKS/SRN GREENS. HIGHS WILL BE CLOSER TO NORMAL IN THE MID30S TO
L40S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE BUILDS IN ACROSS OUR REGION FROM THE SOUTHEAST AS LOW 
PRESSURE TRACKS FROM THE GREAT LAKES TO SOUTHERN QUEBEC THROUGH 
MONDAY.  CHC POPS MOVE INTO THE PICTURE ON MONDAY.  IT'S LOOKING 
LIKE MORE OF A VARIABLE MIXED EVENT THAN IT DID TWO 12-HOUR RUNS 
AGO...RAISING THE DEGREE OF UNCERTAINTY AS TO HOW THIS MIGHT PAN OUT 
DESPITE HOW THE GFS AND ECMWF HAVE NOW COME TOGETHER.  IN A 
NUTSHELL...THIS IS LIKELY A BORDERLINE RAIN/SNOW EVENT WE'RE LOOKING 
AT.

GFS ANALYZES THE 540 THICKNESS LEVEL ACROSS OUR SOUTHERN ZONES AT 
00Z TUE...BEING SUPPRESSED ONLY FURTHER SOUTH OVERNIGHT WITH A 
PASSING COLD FRONT...BUT THE MAIN LOW IS TO THE NORTH WITH A LARGE 
BERMUDA HIGH PROVIDING A SOUTHERLY FLOW DURING THIS TIME.  AT THIS 
TIME...IT'S JUST NOT SAFE TO CHOOSE A SIDE BETWEEN RAIN AND SNOW... 
BUT THE SHOWERY BACK END OF THIS SYSTEM ON TUE IS LIKELY TO BE MORE 
SNOW THAN RAIN...PARTICULARLY IN THE ADIRONDACKS.  NO MATTER THE 
OUTCOME...NEITHER MODEL PRODUCES A GREAT DEAL OF QPF...SO WE'RE NOT 
TALKING ABOUT MUCH UNLESS ICE IS INVOLVED...WHICH THERE'S NOT MUCH 
TOO SUPPORT.

HAVE CHC...THOUGH DECREASING...POPS CONTINUING THROUGH WED...AS GFS 
HAS LOW TRYING TO DEVELOP ALONG THE FRONT OVER THE SOUTHEASTERN PART 
OF THE COUNTRY.  EXTENSIVE CLOUDINESS WILL PROBABLY BE HIGH CLOUDS 
SPRAWLING OUT AHEAD OF THIS LOW...AS HIGH PRESSURE IS PRESENT.

HIGH TEMPERATURES WILL AVERAGE IN THE 40S AHEAD OF THE COLD FRONT  
WITH READINGS DROPPING BACK ABOUT 5 DEGREES ON TUESDAY.  LOWS 
THROUGHOUT THE PERIOD WILL BE MAINLY IN THE 20S AND LOWER 30S.  
AVERAGE HIGHS AND LOWS FOR THE BEGINNING OF DECEMBER ARE AROUND 40 
DEGREES AND THE MID 20S...RESPECTIVELY.

&&

.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
SOUTHERLY FLOW AHEAD OF A WEAK SHORTWAVE TROUGH WILL CONTINUE TO 
BRING LOTS OF LOW LEVEL MOISTURE INTO THE REGION. EARLY THIS 
AFTN...CIGS ARE GENERALLY IN THE VFR/MVFR RANGE...BUT CONDITIONS 
WILL DETERIORATE DOWN TO IFR AT KPOU BY THE MID TO LATE AFTN...AND 
BY THIS EVENING AT KALB...AS LOW STRATUS MOVES UP THE HUDSON VALLEY. 
KGFL WILL LIKELY STAY IN THE VFR/MVFR RANGE THROUGH THE EVENING 
HOURS...BUT THERE IS A CHC FOR SOME IFR THERE AS WELL BY LATE THIS 
EVENING. OVERNIGHT...THE LOW STRATUS WILL HANG AROUND AT ALL 
TERMINALS...ALONG WITH SOME VSBY RESTRICTIONS DUE TO LIGHT MIST. 
THIS MAY EVEN ALLOW FOR SOME LIFR CONDITIONS...MAINLY AT KPOU.

BY THANKSGIVING MORNING...SOME BREAKS IN THE CLOUDS ARE POSSIBLE IF 
SOME MIXING CAN OCCUR...SO A RETURN TO VFR/MVFR CIGS AND VSBYS ARE 
POSSIBLE BY MIDDAY ON THANKSGIVING.

THROUGH THE ENTIRE TAF PERIOD...SOUTHERLY WINDS WILL REMAIN 
LIGHT...GENERALLY 5 KTS OR LESS. 

OUTLOOK... 
THANKSGIVING AFTN...VFR TO MVFR...CIG...NO SIG WX AT THIS TIME. 
THU NGT-FRI...MVFR/IFR...-SHRA.
FRI NGT-SAT...MVFR/IFR...-SHRA CHG TO -SHSNRA. POSS LLWS. WINDY.
SUN...VFR. NO SIG WX.

&&

.HYDROLOGY...
THE NEXT CHANCE OF WIDESPREAD PRECIPITATION WILL BE FROM LATE 
THURSDAY NIGHT INTO THE EARLY PART OF THE WEEKEND...AS A POTENTIALLY 
STRONG STORM MAY IMPACT THE REGION. THERE IS STILL A HIGH AMOUNT OF 
UNCERTAINTY WITH REGARDS TO THE EVOLUTION OF THE STORM AND 
ASSOCIATED QPF. SOME OF THE MODEL GUIDANCE DEPICTING SIGNIFICANT 
QPF ACROSS AREAS NORTH AND EAST OF ALBANY...HOWEVER OTHER SOURCES OF 
GUIDANCE TARGET AREAS TO THE SOUTH AND EAST. DEPENDING ON HOW THE 
STORM EVOLVES...SOME OF THE PRECIP MAY FALL AS SNOW AS 
WELL...ESPECIALLY ACROSS THE HIGHER ELEVATIONS. QPF AMOUNTS AND 
LOCATIONS ARE UNCERTAIN...BUT SOME AREAS MAY RECEIVE GREATER THAN 
ONE INCH. AT THIS TIME IT APPEARS SOME RISES WILL OCCUR ON RIVERS 
BUT SHOULD REMAIN WITHIN THEIR BANKS.

DRY AND WINDY WEATHER IS EXPECTED FOR SATURDAY AS THE STORM PULLS 
AWAY INTO THE CANADIAN MARITIMES. WEAK HIGH PRESSURE WILL RESULT IN 
DRY CONDITIONS THROUGH SUNDAY.

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...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...ELH
AVIATION...FRUGIS
HYDROLOGY...JPV