FXUS61 KALY 101156
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
656 AM EST THU DEC 10 2009

.SYNOPSIS...
AN AREA OF DEEP LOW PRESSURE OVER THE EASTERN GREAT LAKES...
WILL MOVE NORTHEAST ACROSS EASTERN CANADA THROUGH TODAY. WHILE
ANOTHER AREA OF DEEP LOW PRESSURE ALONG THE NEW ENGLAND COAST
MOVES TOWARD THE CANADIAN MARITIMES. STRONG AND GUSTY WESTERLY
WINDS WILL DEVELOP ACROSS THE REGION WILL CONTINUE INTO
SATURDAY USHERING IN A COLD AIRMASS. AS THE COLDER AIR MOVES
ACROSS THE RELATIVELY WARMER WATER OF LAKE ONTARIO...LAKE EFFECT
SNOW WILL DEVELOP OVERNIGHT AND CONTINUE INTO EARLY SATURDAY
IMPACTING THE WESTERN ADIRONDACKS. SIGNIFICANT SNOWFALL IS
EXPECTED.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD ADVECTION OCCURRING...AND INCREASING...AS ARE THE WEST TO
WEST-SOUTHWEST BOUNDARY LAYER WINDS. LAKE EFFECT BAND SEEN
ORGANIZING NOW. MOUNTAIN WAVES SEEN IN SATELLITE IMAGERY ACROSS
THE NORTHEASTERN U.S. THIS SUGGESTS THAT OUTSIDE OF THE LAKE
EFFECT BAND THAT NOSES INTO THE SOUTHERN ADIRONDACKS...SOME
PERIODS OF BREAKS IN THE CLOUDS ARE POSSIBLE THROUGH THE
DAY...ESPECIALLY IN HUDSON VALLEY.

DEPTH OF MOISTURE AND INSTABILITY ALONG AND JUST EAST OF LAKE
ONTARIO SUGGESTS QUITE A LAKE EFFECT EVENT WILL GET GOING. BASED
ON WIDESPREAD BROKEN TO OVERCAST SKY COVER...AND COLD
ADVECTION...HIGHS TODAY MAY OCCUR THIS MORNING...THEN HOLD STEADY
OR SLOWLY FALL IN THE AFTERNOON. TEMPERATURES IN THE MID TO UPPER
30S NOW...AND AGAIN VERY LITTLE VARIATION IN TEMPERATURES THROUGH
THE DAY...EXCEPT TO FALL LATER TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE MAIN EVENT THIS PERIOD WILL BE THE LAKE EFFECT SNOW EVENT
NOSING INTO THE SOUTHERN ADIRONDACKS. THE BAND WILL AFFECT EXTREME
NORTHERN HERKIMER AND HAMILTON COUNTIES TODAY AND INTO
TONIGHT. AS MEAN WIND FLOW GRADUALLY TURNS MORE WESTERLY TONIGHT
THROUGH TOMORROW NIGHT...THE BAND WILL GRADUALLY SHIFT SOUTH. BY
SATURDAY MORNING THE WINDS WILL DIMINISH AND TURN MORE
NORTHWEST...AND SOME SCATTERED SNOW SHOWER ACTIVITY COULD THEN
PUSH THROUGH THE ENTIRE MOHAWK VALLEY...INCLUDING THE CAPITAL
DISTRICT DURING THE DAY SATURDAY.  

BASED ON THE PREDICTED INSTABILITY AND MOISTURE...SOME LOCALIZED
AREAS IN HERKIMER AND HAMILTON COUNTIES WILL PROBABLY NEED A
YARD/METER STICK TO MEASURE THE SNOW BY SATURDAY MORNING. THE LAKE
IS RELATIVELY WARM...AND BOUNDARY LAYER AIR WILL BE SO
COLD...-12C AND COLDER...INSTABILITY WILL BE IMPRESSIVE...AND IDEAL
DENDRITIC GROWTH SHOULD OCCUR. INLAND PENETRATION OF THE BAND INTO
HAMILTON COUNTY IN QUESTION...BUT WILL MONITOR REAL-TIME TRENDS
AND LATEST DATA AS IT HAPPENS. FOR NOW...SUGGESTING BAND NOSES
WELL INTO HAMILTON COUNTY...BUT AGAIN...PERIODIC ADJUSTMENTS MAY
BE NECESSARY THROUGHOUT THE EVOLUTION OF THIS LAKE EFFECT SNOW
EVENT.

OUTSIDE OF THE LAKE EFFECT BAND...MOSTLY CLOUDY TO CLOUDY SKY
SHOULD PREVAIL...WITH AGAIN...SOME INTERVALS OF BREAKS DUE TO SOME
LOCALIZED DOWNSLOPING IN THE VALLEYS. IT WILL BE BREEZY TO
WINDY...WITH SOME GUSTS IN HIGHER ELEVATIONS AND CHANNELED VALLEYS
OVER 40 MPH THIS AFTERNOON AND FRIDAY AFTERNOON. EVEN AT
NIGHT...THE WINDS SHOULD NOT DIMINISH TOO MUCH...AND SOME GUSTS
SHOULD EXCEED 35 MPH LOCALLY. THE CORE OF THE STRONGEST WINDS IS
PREDICTED TO BE NORTH AND WEST OF OUR REGION...SO WITH SOME GUSTS
JUST BELOW ADVISORY CRITERIA THROUGH FRIDAY...NO WIND HEADLINES
AT THIS TIME...BUT IT WILL BE CLOSE.

WITH HIGHS IN THE 20S MANY AREAS FRIDAY...AND LOWS TONIGHT AND
FRIDAY NIGHT IN THE TEENS TO LOWER 20S...SINGLE NUMBERS IN
MOUNTAINS...THE ADDED GUSTY WINDS WILL MAKE IT REALLY FEEL LIKE
WINTER. HIGH PRESSURE BUILDS IN ON SATURDAY AND WINDS DIMINISH...
WITH THE POTENTIAL LAKE EFFECT SNOW SHOWER ACTIVITY POSSIBLE
PUSHING THROUGH THE MOHAWK VALLEY. SOME WEAK WARM ADVECTION ALSO
BEGINS LATER SATURDAY. HIGHS SATURDAY IN THE 20S TO LOWER 30S. FOR
NOW JUST ISOLATED SNOW SHOWERS IN FORECAST...UNTIL EVOLUTION OF
LAKE EFFECT BAND CAN BE SEEN FRIDAY AND FRIDAY NIGHT.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUN/SUN NT...BOTH THE 00Z/10 ECMWF AND GFS DEPICT A POTENTIAL 
INTERACTION BETWEEN A NORTHERN STREAM SHORTWAVE APPROACHING FROM THE 
W...AND A SOUTHERN STREAM FEATURE PASSING E FROM THE OH VALLEY 
TOWARD THE MID ATL COAST. AT THIS TIME...BOTH MODELS INDICATE LITTLE 
IF ANY INTERACTION BETWEEN THE TWO. HOWEVER...GIVEN PAST HISTORY OF 
DISTURBANCES WITHIN THE SOUTHERN STREAM TRACKING FURTHER N THAN 
INITIALLY INDICATED BY MODELS...WILL NEED TO WATCH THIS CLOSELY...AS 
THERE IS SOME POTENTIAL FOR AT LEAST MOISTURE FROM THE SOUTHERN 
STREAM FEATURE TO BECOME ENTRAINED NORTHWARD. AT THIS TIME...WILL 
INDICATE CHC FOR SNOW SHOWERS ACROSS THE ENTIRE REGION. 
OTHERWISE...EXPECT MAX TEMPS TO GENERALLY REMAIN IN THE LOWER/MID 
30S WITHIN VALLEYS...AND 20S ACROSS THE HIGHER TERRAIN...WITH MINS 
SUN NT/MON AM MAINLY IN THE 20S...EXCEPT FOR TEENS ACROSS THE 
WESTERN DACKS.

MON-MON NT...SOME LINGERING SNOW SHOWERS ARE POSSIBLE EARLY 
MON...OTHERWISE WILL INDICATE MAINLY CHC POPS ACROSS FAR NW AREAS 
WHERE ADDITIONAL LAKE EFFECT IS POSSIBLE. EXPECT MAXES TO REACH THE 
MID/UPPER 30S IN VALLEY REGIONS...EXCEPT POSSIBLY THE LOWER 40S 
WITHIN THE MID HUDSON VALLEY...WITH OVERNIGHT MINS MON NT/TUE AM 
MAINLY IN THE 20S.

TUE-WED NT...A SERIES OF NORTHERN STREAM /CLIPPER LIKE/ DISTURBANCES 
MAY PRODUCE SOME LIGHT SNOW/SNOW SHOWERS TUE...ESP ACROSS NORTHERN 
AREAS...WHERE CHC POPS ARE INDICATED. OTHERWISE...MAINLY SLIGHT CHC 
POPS. EXPECT TEMPS TO FALL BELOW SEASONAL LEVELS...ESP TUE NT INTO 
WED.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AN INTENSE LOW PRESSURE SYSTEM WILL CONTINUE TRACKING NORTHEAST 
ACROSS SOUTHEAST CANADA THROUGH THURSDAY...CREATING WINDY 
CONDITIONS ACROSS THE TAF SITES...ALONG WITH PERIODS OF CLOUDS.

PREDOMINANTLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH 
06Z/FRI. THE ONLY EXCEPTION COULD BE BRIEF PERIODS OF MVFR/IFR 
ASSOCIATED WITH SNOW SHOWERS...MAINLY THIS MORNING AT KGFL...AND 
ALSO PATCHY MVFR CLOUDS AT KGFL AND KALB. SOME SNOW SHOWERS/FLURRIES 
COULD OCCUR AT KGFL AND KALB OVER THE NEXT 2-4 HOURS...BEFORE 
TAPERING OFF. ADDITIONAL LIGHT SNOW SHOWERS/FLURRIES ARE POSSIBLE AT 
KGFL AND KALB THIS AFTERNOON...BUT CURRENT PROBABILITIES LOW ENOUGH 
TO PRECLUDE MENTION IN TAFS AT THIS TIME.

WINDS WILL REMAIN FROM THE WEST TO SOUTHWEST OVERNIGHT...GRADUALLY 
INCREASING TO AROUND 10 KT BY SUNRISE...WITH SOME GUSTINESS UP TO 20 
KT POSSIBLE. WINDS WILL THEN INCREASE FURTHER DURING THIS 
MORNING...REACHING 10-20 KT BY EARLY THIS AFTERNOON...ALONG WITH 
POSSIBLE GUSTS OF 25-30 KT. THESE WINDS WILL PERSIST THROUGH 
06Z/FRI. 

OUTLOOK...
FRI...WINDY. VFR-MVFR FOR MAINLY CIGS WITH CHC -SHSN AND LAKE 
EFFECT SNOW DOWNWIND FROM LAKE ONTARIO.
SAT...VFR...NO SIG WX.
SUN-MON...MAINLY VFR WITH A SLIGHT CHC -SHSN.

&&

.HYDROLOGY...
WE WILL STAY COLD ENOUGH FOR LITTLE OR NO SNOW MELT.
OTHERWISE...NO HYDRO PROBLEMS ARE FORESEEN FOR THE 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...NONE.
NY...LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR NYZ032-
     033.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...NAS
NEAR TERM...NAS
SHORT TERM...NAS
LONG TERM...KL
AVIATION...KL
HYDROLOGY...KL/NAS