FXUS61 KALY 102328
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
628 PM EST THU DEC 10 2009

.SYNOPSIS...
DEEP LOW PRESSURE WILL CONTINUE MOVING NORTHEAST ACROSS EASTERN 
CANADA THROUGH FRIDAY. LARGE ARCTIC HIGH PRESSURE WILL SETTLE IN TO 
OUR SOUTH. THE RESULT WILL BE STRONG AND GUSTY WESTERLY WINDS 
CONTINUING. AS THE COLDER AIR MOVES ACROSS THE RELATIVELY WARMER 
WATER OF LAKE ONTARIO...LAKE EFFECT SNOW WILL CONTINUE INTO EARLY 
SATURDAY IMPACTING THE WESTERN ADIRONDACKS WITH SIGNIFICANT 
SNOWFALL.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 500 PM...TYX RADAR AND WEB CAMS INDICATE A FULL BLOWN LAKE 
EFFECT FINALLY REACHING THE OLD FORGE AREA OF HERKIMER COUNTY. IT 
HAS ALREADY BEEN SNOWING...HEAVILY AT TIMES...ACROSS THE EXTREME 
NORTHERN PORTIONS OF HERKIMER COUNTY. AS THE LOW LEVEL MEAN WIND 
FLOW VEERS FROM ABOUT A 260 TO A 280 VECTOR THIS BAND WILL SLOWLY 
SINK SOUTHWARD INTO HERKIMER AROUND ROUTE 28 AND SHOULD EXTEND INTO 
HAMILTON AND POSSIBLY EVEN WARREN COUNTY. OCCASIONALLY...THE WINDS MIGHT 
AT TIMES BE STRONG ENOUGH TO DISRUPT THE BAND (AS WELL AS SHORT 
WAVES PERTURBING THROUGH THE FLOW). NEVERTHELESS...TONIGHT AS THE 
WIND BACKS OFF A LITTLE AND THE FLOW BECOMES BETTER ALIGNED OFF THE 
LAKES WITH TEMPERATURES DROPPING LOW ENOUGH TO PRODUCE EXTREME 
SLANTWISE INSTABILITY OFF LAKE ONTARIO...THE SNOW INTENSITY WILL 
LIKELY INCREASE EVEN MORE. 

EITHER WAY...THIS LOOKS TO BE A LONG LIVED AND PROLIFIC LAKE SNOW 
EVENT FOR PORTIONS OF OUR SOUTHERN ADIRONDACKS. WARNINGS REMAIN 
POSTED FOR BOTH HAMILTON AND NORTHERN HERKIMER COUNTIES UNTIL AT 
LEAST 12Z SATURDAY. WE STILL EXPECT 1 TO LOCALLY THREE FEET OF SNOW 
IN THIS AREA WHEN THE LAKE EFFECT WINDS DOWN ON SATURDAY. PLEASE 
REFER TO ALL OF OUR WINTER WEATHER MESSAGE (WSW) AND NOWCASTS FOR 
UPDATES ON THIS EVENT.   

SNOW SHOWERS HAVE BEEN AFFECTING OTHER AREAS OF THE MOHAWK VALLEY...INTO 
SOUTHERN VERMONT. THESE WERE MORE CELLULAR LOOKING AND IN ADDITION TO 
LAKE MOISTURE ARE PARTIALLY THE RESULT OF COLD AIR ADVECTION 
PRODUCING UPRIGHT (AS OPPOSED TO SLANTWISE) INSTABILITY. THE WIND IS 
TURNING MORE WESTERLY (AS OPPOSED TO SOUTHWESTERLY) SO SOME UPSLOPE 
IS TAKING PLACE ALONG THE SPINE OF THE SOUTHERN GREENS. AS THE WIND 
EVENTUALLY TURNS NW...THE UPSLOPE THERE SHOULD INTENSIFY A 
LITTLE. 

RIGHT NOW...THIS SCENARIO LOOKS TO PRODUCE LOCALIZED ACCUMULATIONS 
OF SNOW BELOW ADVISORY THRESHOLD. HOWEVER WE WILL CONTINUE TO 
MONITOR THE SITUATION. 

ALSO...THE WINDS WILL KICK UP A BIT AS THE GRADIENT TIGHTENS BETWEEN 
DEPARTING LOW PRESSURE INTO CANADA...AND HIGH PRESSURE BUILDING IN 
TO OUR SOUTH. WITH THE EXCEPTION OF BUFFALO...THERE WERE NO PENNANTS 
(50KT WINDS) UPSTREAM OF OUR REGION. THE 50KT JET OVER BUFFALO WILL 
LIKELY WEAKEN A LITTLE AS IT HEADS EASTWARD. WE ARE FORECASTING WIND 
GUSTS TO REMAIN JUST BELOW WIND ADVISORY BUT IT WILL BE VERY CLOSE. 
FOR NOW...NO WIND HEADLINES WILL BE ISSUED BUT WE WILL MENTION OUR 
CONCERNS IN THE HAZARDOUS WEATHER OUTLOOK.

AS ARCTIC AIR IS SLOWLY DRIVEN INTO THE REGION...TEMPERATURES SHOULD 
DROP DOWN TO AROUND 20 FOR OVERNIGHT LOWS LOCALLY...TEENS OUTLYING 
AREAS...EXCEPT SINGLE DIGITS ACROSS THE HIGHEST TERRAIN. WIND CHILL 
READINGS WILL DIP BELOW ZERO IN THE MOUNTAINS...SINGLE DIGITS 
ELSEWHERE. COLD...BUT NOT LOW ENOUGH FOR ADVISORIES.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
THE SAME ISSUES...LAKE EFFECT/WIND AND COLD WILL BE THE THEME FRIDAY 
INTO FRIDAY NIGHT. H850 TEMPERATURES ARE FORECAST TO DIP BETWEEN -18 
TO -15C ACROSS OUR REGION. IRONICALLY...THE COLDEST VALUES ARE FOUND 
IN OUR SOUTHERN AREAS! H850 TEMPERATURES STAY CLOSE TO THESE VALUES 
INTO SATURDAY.

THE TREMENDOUS LAKE EFFECT IMPACTING NORTHERN HERKIMER AND HAMILTON 
COUNTIES SHOULD CONTINUE INTO AT LEAST SATURDAY MORNING. SOME 
UPSLOPE SNOW SHOWERS WILL PERSIST ACROSS THE GREENS. THE REST OF THE 
AREA WILL SEE ISOLATED TO SCATTERED SNOW SHOWERS WILL LITTLE OR NO 
SNOW ACCUMULATIONS OUTSIDE OF A A COUPLE INCHES POSSIBLE IN THE 
MOHAWK VALLEY. 

TEMPERATURES ON FRIDAY WILL BE QUITE A BIT COLDER THAN TODAY 
(THURSDAY). WE EXPECT READINGS TO TOP OUT ONLY NEAR 30 IN THE MID 
HUDSON VALLEY/LITCHFIELD COUNTY...WITH 20S MOST OTHER PLACES...EXCEPT 
TEENS ACROSS THE MOUNTAINS. THE WIND WILL MAKE THESE VALUES FEEL 
COLDER. COLD FRIDAY NIGHT WITH LOWS TUMBLING INTO THE TEENS AND 
SINGLE DIGITS. ENOUGH OF A BREEZE AND LAKE EFFECT CLOUDS SHOULD KEEP 
MOST PLACES ABOVE ZERO...EXCEPT FOR PERHAPS A FEW SNOW COVERED 
MOUNTAIN VALLEYS.

SATURDAY WILL SEE SIMILAR CONDITIONS TO FRIDAY EXCEPT THE LAKE 
EFFECT BAND OFF LAKE ONTARIO MIGHT BEGIN SLIPPING TOWARD THE NEW 
YORK STATE THRUWAY. IF THIS HAPPENS...THE HEAVIEST SNOW WOULD FALL 
JUST SOUTH OF ROUTE 28 AND A FEW OF THESE SHOWERS COULD MAKE IT INTO 
THE CAPITAL REGION. UPSLOPE SCATTERED SNOW SHOWERS WILL CONTINUE 
ACROSS VERMONT AND POSSIBLY EVEN INTO THE BERKSHIRES. HIGH 
TEMPERATURES WILL BE SIMILAR TO FRIDAY HIGHS...GENERALLY IN THE 
20S...TO AROUND 30 IN OUR SOUTHERN ZONES. 
  
EVENTUALLY...HIGH PRESSURE WILL SETTLE OVER OUR REGION BY SATURDAY 
NIGHT. THIS MIGHT BE OUR COLDEST NIGHT. BY THIS TIME HOWEVER...THERE 
ARE INDICATIONS THAT HIGH CLOUDS MIGHT ALREADY BE MOVING IN AHEAD OF 
THE NEXT SYSTEM. FOR NOW...DID FORECAST TEMPS MUCH COLDER THAN 
FRIDAY NIGHT...BUT IF IT WERE TO CLEAR...THEY WOULD TURN OUT A LOT 
COLDER AS THE WIND WILL BE LIGHT. BY THIS TIME...ALL LAKE EFFECT 
SNOW...SHOULD BE OVER.

ON SUNDAY...AS HIGH PRESSURE RETREATS OFFSHORE IT WILL PRODUCE WARM 
AIR ADVECTION CLOUDS. THE GFS HAS BEEN INDICATING FOR QUITE A FEW 
ROUNDS NOW...A WEAK SOUTHERN STREAM SYSTEM TRENDING A LITTLE FURTHER 
NORTH WITH EACH RUN. THE TREND IS NO LONGER FURTHER NORTH...BUT A 
WEAK LOW TRACKS OFF THE CAROLINA COAST. THE COMBINATION OF A RETURN 
SOUTHERLY FLOW...THE WARM AIR ADVECTION...AND LOW LEVEL CONVERGENCE 
FROM AN INVERTED TROUGH EXTENDING NORTHWARD FROM THE LOW 
PRESSURE...LOOK MORE AND MORE LIKELY TO PRODUCE A PERIOD OF SNOW 
ACROSS MUCH OF THE AREA...ESPECIALLY SOUTH OF ALBANY. NOW...THE 
EUROPEAN/NAM AND EVEN CANADIAN GEM SUPPORT SOME OF PRECIPITATION 
DEVELOPING ACROSS THE AREA...WITH THE EUROPEAN THE LIGHTEST THUS 
FAR. IT DOES NOT LOOK LIKE A BIG STORM...BUT COULD POTENTIALLY 
PRODUCE UP TO ADVISORY LEVELS ESPECIALLY SOUTH. HOWEVER...THE COLUMN 
MIGHT ACTUALLY WARM UP ENOUGH FOR A LITTLE RAIN TO MIX IN SOUTH. FOR 
NOW...JUST WENT WITH A GENERIC 50 PERCENT OF SNOW EVERYWHERE AS THE 
POSSIBLE EVENT IS STILL DAYS AWAY. WHATEVER STORM WE DO GET IS 
EXPECTED TO SLOWLY MOVE OFFSHORE SUNDAY NIGHT WITH A BIT MORE 
RESIDUAL SNOW.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
CONDITIONS WILL DRY FOR MONDAY WITH A WEAK RIDGE OF HIGH PRESSURE 
BUILDING IN BEHIND SUNDAY/S POSSIBLE STORM. SOME LINGERING SHOWERS 
ARE POSSIBLE EARLY MONDAY. WEAK HIGH PRESSURE WILL NOT LAST LONG AS 
RATHER ZONAL FLOW OVER THE US WILL ALLOW THE NEXT SYSTEM TO QUICKLY 
MOVE IN FROM THE WESTERN GREAT LAKES BY MONDAY NIGHT INTO TUESDAY. 
PRECIPITATION FROM THIS STORM WILL START OFF AS SNOW...TRANSITIONING 
TO RAIN IN THE AFTERNOON...EXCEPT FOR ELEVATIONS ABOVE 1500 FEET 
WHICH WILL SEE A RAIN/SNOW MIX ON TUESDAY. TUESDAY NIGHT 
TEMPERATURES WILL BE COLD ENOUGH TO TRANSITION THE RAIN BACK TO SNOW 
ACROSS THE FA...WITH SNOW TAPERING OFF ON WEDNESDAY MORNING. BEHIND 
THIS SYSTEM...NORTHWESTERLY FLOW WILL PREVAIL...KEEPING A CHC OF 
SNOW OVER THE ADIRONDACKS FROM LAKE EFFECT SNOW SHOWERS THROUGH LATE 
WEDNESDAY/EARLY THURSDAY. OTHERWISE...SFC HIGH PRESSURE WILL RETURN 
LATE THURSDAY.

THE PERIOD WILL START WITH ABOVE NORMAL TEMPERATURES FOR MONDAY AND 
TUESDAY. AFTER THE NEXT SYSTEM ON LATE MONDAY INTO TUESDAY...COLDER 
AIR WILL FILTER IN WITH TEMPERATURES DECREASING TO 5-10 DEGREES 
BELOW NORMAL THROUGH THE REST OF THE PERIOD.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE WITH MAIN CONCERN BEING
STRONG AND GUSTY WINDS. THE GUSTY WINDS WILL CONTINUE TO BE A
PROBLEM AT ALL TERMINALS THROUGH THE NEXT 24 HRS...ESPECIALLY
ALBANY WHERE GUSTS COULD APPROACH 40KTS FRIDAY AFTERNOON. LAKE
EFFECT CLOUDS ARE EXPECTED TO REMAIN AT VFR CIGS...EXCEPT IN SNOW
SHOWERS WITH MVFR CIGS AND VSBYS POSSIBLE. ANY SNOW SHOWERS WILL
BE SHORT LIVED AT THE TERMINALS. OTHERWISE...VFR CONDITIONS WILL
PREVAIL.

OVERNIGHT WINDS WILL DECREASE TO 10-15KT WITH GUSTS 20-25KTS.
WINDS AND WIND GUSTS WILL INCREASE AT ALL TERMINALS FRIDAY
MORNING...CONTINUING TO INCREASE THROUGH THE AFTERNOON WITH
GUSTS 30-40KTS. WINDS WILL DECREASE SLIGHTLY AFTER SUNSET.

OUTLOOK...
SAT...VFR...WINDY WITH A CHC MVFR AT GFL IN LAKE EFFECT -SHSN. 
SAT NT...VFR...NO SIG WX.
SUN...VFR GOING TO MVFR CIG...CHC IFR IN -SN.
MON...VFR...NO SIG WX.
TUE...MVFR...CIG. CHC -RASN.

&&

.HYDROLOGY...
WE WILL STAY COLD ENOUGH FOR LITTLE OR NO SNOW MELT.
OTHERWISE...NO HYDRO PROBLEMS ARE FORESEEN FOR THE NEXT WEEK.

SOME ICE MIGHT BEGIN TO FORM ACROSS THE NORTHERN SECTIONS OF OUR 
HYDRO AREA AS TEMPERATURES DIP DOWN TO THE TEENS OR LOWER.

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...HWJIV
NEAR TERM...HWJIV
SHORT TERM...RCK
LONG TERM...KGS
AVIATION...ELH/KGS
HYDROLOGY...HWJIV