FXUS61 KALY 011446
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
946 AM EST TUE DEC 1 2009

.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST 
TODAY...BRINGING CLOUDS...ALONG WITH SCATTERED SNOW AND RAIN SHOWERS 
TO THE REGION. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION 
TONIGHT AND WEDNESDAY...PROVIDING FAIR AND MILD CONDITIONS. A STRONG 
LOW PRESSURE SYSTEM WILL TRACK FROM THE GULF COAST INTO THE EASTERN 
GREAT LAKES WEDNESDAY NIGHT AND THURSDAY...BRINGING A SOAKING RAIN 
TO THE REGION...FOLLOWED BY COLDER AIR FOR THE END OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHORT WAVE MOVING THROUGH LONGWAVE TROUGH ACROSS REGION. HAVE
WEAK SURFACE LOW REFLECTED AT SURFACE. HAVE STEEP LAPSE RATES
ACROSS AREA THIS MORNING. SNOW SHOWERS MOVING INTO THE EASTERN
CATSKILLS HAVE INCREASED POPS THERE. OTHERWISE...MINOR UPDATES 
TO REST OF GRIDS. FOR TODAY. WILL LIKELY UPDATE GRIDS BY EARLY
AFTERNOON.

PREVIOUS DISCUSSION AS OF 4 AM EST...A WEAK SHORTWAVE RIDGE
CONTINUES TO SLIDE E ACROSS THE REGION...BRINGING A PERIOD OF
MOSTLY CLEAR SKIES...AND LIGHT TO CALM WIND. THIS HAS ALLOWED
TEMPS TO DROP QUICKLY INTO THE MID/UPPER 20S IN MOST VALLEY
LOCALES...WITH SOME TEENS TO LOWER 20S ACROSS THE NORTH COUNTRY.
MID LEVEL CLOUDS ARE QUICKLY ADVANCING E FROM THE GREAT LAKES...IN
RESPONSE TO STRENGTHENING WARM ADVECTION TO THE E OF A SFC
LOW...CURRENTLY ACROSS THE NORTHERN GREAT LAKES. RATHER STRONG
MID/UPPER LEVEL DYNAMICS...IN ADDITION TO WARMTH/MOISTURE FROM THE
LAKES WAS CONTRIBUTING TO A BLOSSOMING AREA OF PRECIP...MAINLY
SNOW...ACROSS WESTERN NY AND THE EASTERN GREAT LAKES. WE EXPECT
THIS FEATURE TO CONTINUE SLIDING E...ALBEIT IN A WEAKENING STATE
LATER THIS MORNING INTO THE AFTERNOON...BRINGING SCATTERED TO
NUMEROUS SHOWERS OF SNOW AND RAIN.

WE EXPECT SNOW SHOWERS TO BE MOST NUMEROUS ACROSS THE SW 
DACKS...WHERE AFOREMENTIONED UPPER LEVEL DYNAMICS...MORE AMPLE 
MOISTURE AND INSTABILITY WILL ENHANCE PRECIP. THUS...WE EXPECT 
OCCASIONAL SNOW SHOWERS IN THIS REGION...WHERE 1-3 INCHES OF ACCUM 
IS POSSIBLE. THERE COULD BE A FEW HEAVIER BURSTS OF SNOW FROM MID 
MORNING INTO THE EARLY AFTERNOON HOURS IN THIS REGION. FURTHER 
S/E...WE EXPECT SCATTERED TO NUMEROUS SNOW SHOWERS FROM LATE MORNING 
INTO THE MID AFTERNOON HOURS...WITH SOME RAIN MIXING IN WITHIN THE 
VALLEY LOCALES...AS BOUNDARY LAYER TEMPS WARM THROUGH A DEEP ENOUGH 
LAYER TO MELT SOME OF THE SNOW. WITHIN THIS REGION...A BRIEF DUSTING 
IS POSSIBLE ACROSS HIGHER ELEVATIONS WITHIN THE SCHOHARIE 
VALLEY/WESTERN MOHAWK VALLEY...AS WELL AS ACROSS W FACING HIGHER 
ELEVATIONS WITHIN THE NORTHERN TACONICS...SOUTHERN GREENS AND 
NORTHERN BERKSHIRES. FURTHER S/E...ONLY SOME SPRINKLES OR FLURRIES 
ARE EXPECTED...ALTHOUGH SNOW SHOWERS ARE MORE LIKELY ACROSS THE 
HIGHER ELEVATIONS WITHIN THE EASTERN CATSKILLS.

FOR MAX TEMPS...WE EXPECT FAIRLY DEEP MIXING TO AROUND 850-875 MB 
WITH THE PASSAGE OF MID/UPPER LEVEL COLD POOL. HOWEVER...THIS SHOULD 
BE MITIGATED SOMEWHAT BY CLOUDS AND POSSIBLE PRECIP. THUS...WE HAVE 
GENERALLY SIDED CLOSE TO...OR A TAD BELOW A MAV/MET MOS BLEND...WITH 
LOWER 40S EXPECTED WITHIN THE HUDSON RIVER VALLEY...EXCEPT FOR SOME 
MID 40S WITHIN THE MID HUDSON VALLEY...AND MAINLY 30S ACROSS HIGHER 
ELEVATIONS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...SOME LINGERING SNOW SHOWERS/FLURRIES ARE POSSIBLE 
EARLY...ESP ACROSS THE SW DACKS...AND HIGHER...WEST FACING AREAS 
WITHIN SW VT. THEREAFTER...THE MAIN FORECAST CHALLENGE WILL BE THE 
EXTENT OF LINGERING CLOUDS...AND MIN TEMPS. WE EXPECT THE INVERSION 
TO LOWER RAPIDLY OVERNIGHT...WHICH...IN COMBINATION WITH W/NW WIND 
FLOW WITHIN THE 925-850 MB LAYER CROSSING THE GREAT LAKES...MAY TRAP 
MOISTURE BELOW...RESULTING IN AREAS OF CLOUDS. MODELS OFTEN HAVE A 
DIFFICULT TIME WITH SUCH MOISTURE/CLOUDS...TENDING TO CLEAR THEM OUT 
TOO QUICKLY. WE THEREFORE HAVE KEPT AT LEAST SOME CLOUDS FOR 
NORTHERN AND CENTRAL AREAS THROUGH MIDNIGHT...POSSIBLY PERSISTING 
ACROSS NORTHERN AREAS THROUGH DAYBREAK. THIS SHOULD RESULT IN 
SLIGHTLY MILDER TEMPS THAN THIS MORNING...AND HAVE SIDED WITH THE 
WARMER MET MOS FOR MINS...WITH THE EXCEPTION OF SOUTHERN 
AREAS...WHERE SKIES ARE MORE LIKELY TO CLEAR EARLIER...ALLOWING MINS 
TO FALL INTO THE MID/UPPER 20S.

WED...ANY MORNING LOW CLOUDS SHOULD BRIEFLY BREAK...ONLY TO YIELD TO 
THICKENING HIGH/MID LEVEL CLOUDS FROM THE SOUTHWEST AS WARM 
ADVECTION COMMENCES WITH APPROACHING STORM SYSTEM FROM THE GULF 
COAST. SOME LIGHT RAIN COULD DEVELOP TOWARD EVENING...ESP FOR AREAS 
S AND W OF THE CAPITAL REGION...WHERE CHC POPS ARE INDICATED. AS FOR 
MAX TEMPS...WE EXPECT SHALLOW MIXING...ONLY TO 950-925 
MB...WHICH...IN COMBINATION WITH INCREASING CLOUDS...SHOULD ALLOW 
MAXES TO REACH 45-50 WITHIN THE VALLEYS...AND MAINLY LOWER 40S 
ACROSS THE NORTH COUNTRY/SOUTHERN VT. THESE MAXES ARE GENERALLY 
COOLER THAN A MAV/MET MOS BLEND BY A FEW DEGREES.

WED NT-THU...POWERFUL LOW LEVEL JET APPROACHES/TRAVERSES THE REGION 
LATE WED NT...ALONG WITH STRONG MOISTURE TRANSPORT. THIS SHOULD 
ALLOW FOR RAIN TO DEVELOP QUICKLY IN THE EVENING...AND CONTINUE 
OVERNIGHT...WITH A FEW PERIODS OF HEAVY RAIN POSSIBLE...ESP ACROSS 
THE WESTERN DACKS...AND S/E FACING SLOPES WITHIN THE CATSKILLS AND 
TACONICS. A FEW RUMBLES OF THUNDER CAN NOT BE RULED OUT...ESP ACROSS 
SOUTHERN AREAS TOWARD THU AM...GIVEN FORECAST 850 LI'S DIPPING INTO 
SLIGHTLY NEGATIVE NUMBERS. THE OTHER MAIN STORY WILL BE THE 
POTENTIAL FOR STRONG WINDS...ESP WITHIN CHANNELED N/S ORIENTED 
VALLEYS WITHIN THE BERKSHIRES...TACONICS...AND GREENS...WHERE GUSTS 
COULD APPROACH ADVISORY LEVELS. WE WILL ADDRESS THIS POTENTIAL IN 
THE HWOALY. OTHERWISE...WE EXPECT ANY MINS TO OCCUR EARLY WED 
NT...WITH TEMPS RISING RAPIDLY LATER AT NIGHT GIVEN THE STRONG S/SE 
FLOW. MAX TEMPS SHOULD THEN OCCUR THU MORNING...WHEN DEEPEST MIXING 
OCCURS NEAR OR JUST BEHIND COLD FRONT...WITH TEMPS FALLING THU 
AFTERNOON. WE HAVE LEANED CLOSE TO THE WARM MET MOS FOR 
MAXES...YIELDING LOWER/MID 60S WITHIN VALLEYS...AND 50S FOR HIGHER 
ELEVATIONS...WITH TEMPS THEN FALLING THROUGH THE 50S AND 40S DURING 
THE AFTERNOON. AS FOR RAIN...WE EXPECT STEADY RAIN TO BECOME MORE 
SHOWERY BY SUNRISE THU...WITH SHOWERS TAPERING RAPIDLY FROM W TO E 
ONCE COLD FRONTAL PASSAGE OCCURS. WINDS MAY ONCE AGAIN APPROACH 
ADVISORY LEVELS BEHIND THIS FRONT...GIVEN STRONG SFC PRESSURE RISES 
AND INTENSIFYING COLD ADVECTION DURING THE AFTERNOON HOURS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THU NIGHT INTO SAT...IN THE WAKE OF THE SURFACE LOW STRONG COLD AIR 
ADVECTION TAKES PLACE WITH FAIRLY STRONG CYCLONIC FLOW AND AS A 
RESULT SOME LAKE EFFECT SNOWS ARE POSSIBLE ESPECIALLY ACROSS THE 
WESTERN ADIRONDACKS AND NORTHERN PORTIONS OF THE MOHAWK VALLEY. THIS 
LOOKS TO BE A FAIRLY PROLONGED LAKE EFFECT EVENT AS LAKE ONTARIO 
TEMPS WILL LIKELY STILL BE IN THE MID 40S AND H8 TEMPS IN THIS AREA 
LOOK TO DROP TO AROUND -10 C LATE THURSDAY NIGHT AND REMAIN AROUND 
-10 C ON FRIDAY AND DROP TO AROUND -12 C ON FRIDAY NIGHT AND 
SATURDAY. OUTSIDE OF THE LAKE EFFECT BAND MAINLY DRY BUT COOL 
WEATHER IS EXPECTED DURING THIS PERIOD. HAVE LOWS THURSDAY NIGHT IN 
THE MID 20S TO LOWER 30S...HIGHS FRIDAY IN THE MID 30S TO MID 
40S...LOWS FRIDAY NIGHT IN THE UPPER TEENS TO MID 20S AND HIGHS ON 
SATURDAY IN THE 30S TO AROUND 40.

SATURDAY NIGHT THROUGH SUNDAY NIGHT LOOKS TO BE MAINLY DRY AS THE 
LOW LEVEL FLOW BECOMES ANTICYCLONIC WHICH SHOULD CAUSE THE LAKE 
EFFECT ACTIVITY TO WEAKEN WITH A RIDGE OF HIGH PRESSURE BUILDING IN 
AT THE SURFACE. H8 TEMPS LOOK TO BOTTOM OUT ACROSS FA AT AROUND -12 
TO -13 C EARLY SUNDAY MORNING AND THEN SLOWLY RISE TO -7 TO -11 C BY 
MONDAY MORNING. HAVE LOWS SATURDAY NIGHT IN THE MID TEENS TO MID 
20S...HIGHS ON SUNDAY IN THE UPPER 20S TO LOWER 40S AND LOWS SUNDAY 
NIGHT IN THE MID TEENS TO MID 20S.

ON MONDAY EXPECT CLOUDS TO INCREASE AGAIN AHEAD OF ANOTHER CLIPPER 
TYPE SYSTEM MOVING INTO THE EASTERN GREAT LAKES WITH A CHANCE OF 
SNOW SHOWERS ACROSS THE SOUTHERN ADIRONDACKS AND MOHAWK VALLEY. 
HIGHS MONDAY LOOK TO BE IN THE UPPER 20S TO AROUND 40.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
CLOUDS HAVE INCREASED AND WILL LOWER TODAY WITH MVFR CONDITIONS
ARE POSSIBLE AT KALB. SHOWERS ARE MOVING EASTWARD ACROSS THE AREA
HAVE ADDRESSED WITH VICINITY SHOWER IN TAFS AS ACTIVITY SHOULD
WEAKEN AS IT MOVES EASTWARD. AFTER SUNSET SKIES ARE EXPECTED TO
CLEAR ONCE AGAIN. WINDS WILL BE GENERALLY LIGHT LESS THAN 10 KNOTS
SOUTHERLY BECOMING WESTERLY THIS AFTERNOON...THEN DIMINISH THIS
EVENING.

OUTLOOK... 
TUE NIGHT-WED...VFR. NO SIG WX. 
WED NIGHT-THU...MVFR-IFR IN RAIN.
FRI-SAT...VFR...CHC OF -SHRA/-SHSN.

&&

.HYDROLOGY...
NO HYDRO PROBLEMS ARE ANTICIPATED THROUGH WEDNESDAY. SOME SHOWERS OF 
SNOW AND RAIN ARE EXPECTED TODAY THROUGH THIS EVENING IN ASSOCIATION 
WITH A PASSING UPPER LEVEL DISTURBANCE. LIQUID EQUIVALENT AMOUNTS 
SHOULD RANGE FROM ONE TENTH...TO ONE QUARTER OF AN INCH ACROSS THE 
WESTERN ADIRONDACKS...WITH LESS THAN ONE TENTH OF AN INCH EXPECTED 
ELSEWHERE. 

A SYSTEM APPROACHING FROM THE OHIO VALLEY MAY BRING A WIDESPREAD 
RAINFALL...WITH TOTAL RAINFALL LIKELY EXCEEDING AN INCH...WEDNESDAY 
NIGHT AND EARLY THURSDAY. ALTHOUGH TOTAL FORECAST RAINFALL DOESN'T 
APPEAR TO BE ENOUGH TO CAUSE WIDESPREAD FLOODING...DETERMINISTIC AND 
ENSEMBLE GUIDANCE INDICATE THAT MOST OF THE RAIN WILL FALL IN A 6 TO 
12 HOUR PERIOD. HIGH INTENSITY RAINFALL MAY CAUSE SOME URBAN AND 
SMALL STREAM FLOODING ON THURSDAY MORNING. DRY...COLD WEATHER WILL 
FOLLOW WITH THE BEST CHANCE FOR MORE PRECIPITATION ON SATURDAY. 
PRECIPITATION TYPE ON SATURDAY LOOKS TO BE SNOW. STREAMS IN THE 
ADIRONDACKS MAY START TO SEE SOME RIVER ICE FORMATION EARLY 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...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...KL
NEAR TERM...IAA/KL
SHORT TERM...KL
LONG TERM...11
AVIATION...IAA/11
HYDROLOGY...SND/KL