FXUS61 KALY 051604
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1104 AM EST SAT DEC 5 2009

.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL CONTINUE TO MOVE 
NORTHEASTWARD OFF THE EASTERN SEABOARD THIS AFTERNOON INTO 
TONIGHT...SPREADING A PERIOD OF LIGHT SNOW ACROSS THE EASTERN 
PORTIONS OF THE AREA. BEHIND THIS SYSTEM...HIGH PRESSURE WILL BUILD 
INTO THE AREA...ALLOWING FOR DRY CONDITIONS FOR TOMORROW INTO 
MONDAY. A MORE SIGNIFICANT SYSTEM MAY SPREAD PRECIPITATION INTO THE 
REGION FOR THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST MSAS ANALYSIS SHOWS PRESSURE FALLS OF 3-4 MB PER 3 HRS
SEVERAL HUNDRED MILES OFF THE VIRGINA CAPES AS LOW PRESSURE IS
TAKING SHAPE. RADAR MOSAIC SHOWS PRECIP MOVING INTO SOUTHERN
NY...ALTHOUGH WITH DRY AIR IN PLACE AT THE SFC /DEWPOINT
DEPRESSIONS STILL 10 DEGREES F/...MUCH OF THIS IS VIRGA AND
HASN/T REACHED THE GROUND JUST YET. AS BOUNDARY LAYER MOISTENS
UP...WILL EXPECT PRECIP TO BEGIN IN DUTCHESS AND LITCHFIELD
COUNTIES WITHIN THE NEXT FEW HOURS...AND PROBABLY IN THE FORM OF
RAIN. HOWEVER...AS TEMPS LOWER TO THE WET BULB TEMP...THE RAIN WILL
EVENTUALLY CHANGE TO SNOW BY LATER THIS AFTN.

PRECIP WILL CONTINUE TO WORK FARTHER NORTH...AND LATEST 12 UTC NAM
SUPPORTS THIS IDEA...SO HAVE BROUGHT CATEGORICAL POPS UP TO THE
CAPITAL REGION AND ACROSS SOUTHERN VERMONT. WILL CONTINUE THE
WINTER WEATHER ADVISORY FOR THE LITCHFIELD HILLS WHERE 3-6 INCHES
OF SNOW IS EXPECTED ONCE THE RAIN CHANGES THE SNOW BY LATE AFTN.
WILL ALSO CONTINUE THE ADVISORY FOR THE BERKSHIRES AND DUTCHESS
COUNTY...ALTHOUGH SNOW AMOUNTS LIKELY WON/T REACH TRADITIONAL
ADVISORY CRITERIA...AS JUST 2-4 INCHES ARE EXPECTED IN THESE
AREAS. FARTHER NORTH AND WEST...LESS QPF WILL RESULT IN JUST AN
INCH OR SO OF ACCUMULATION FOR THE CAPITAL REGION...AND 1-3 ACROSS
SOUTHERN VERMONT. THE BEST SNOW ACCUM WILL LIKELY OCCUR THIS
EVENING AS THE LOSS OF THE SUN SHOULD HELP ALLOW FOR SNOW TO
ACCUMULATE ON THE RELATIVELY WARM AND UNFROZEN GROUND. THE BEST
FGEN FORCING CONTINUES TO LOOK TO REMAIN WELL EAST OUR AREA...A
RESULT OF THE SFC LOW AND ASSOCIATED 850-700 HPA THERMAL GRADIENT
BEING SITUATED WELL OFFSHORE. THIS SHOULD KEEP SNOW GENERALLY
LIGHT ACROSS OUR AREA AS OUR FORCING FOR PRECIP WILL BE A RESULT
OF THE 500 HPA LOW AND ASSOCIATED COLD CONVEYOR BELT AND
DEFORMATION...PREVENTING ANY SIGNIFICANT SNOW RATES AND
ACCUMULATIONS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
500HPA TROF MOVES OFFSHORE TONIGHT AND SHUTS THE PRECIPITATION OFF
OVERNIGHT. SFC LOW WELL EAST OF FCA IN N ATLC SUNDAY BUT 500 HPA
TROF CUTS OFF AND STORM DEEPENS AS SFC HIGH PUSHES EAST TWRD RGN
FM OHIO AND TENNESSEE VLY. CREATES A GRADIENT AND A BREEZY SUNDAY
OVER FCA. RGN IS ON NORTH SIDE OF SFC HIGH. LATE SUNDAY A
SECONDARY FRONT APPROACHES THE SAINT LAWRENCE VALLEY AND DROPS
SOUTH INTO REGION SUNDAY NIGHT. THIS FRONT ALONG WITH SOME WEAK
500HPA SHORT WAVES ACTS A FOCUS FOR CLOUDS TO OVERSPREAD REGION
MAINLY NORTH AND A FOCUS OF LAKE EFFECT -SHSN BAND INTO THE
WESTERN ADIRONDACKS. WHILE CONDITIONS ARE NOT OPTIMAL FOR LAKE
RESPONSE AND BOUNDARY LEVEL WINDS TURN N-NE BEHIND THE FRONT..THEY
WILL BE SUFFICIENT FOR GARDEN VARIETY -SHSN SUN NIGHT IN WESTERN
ADIRONDACKS.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
HIGH PRESSURE SHIFTS EAST INTO THE ATLANTIC AS A CLIPPER TYPE
LOW MOVES FROM THE MIDWEST ACROSS THE EASTERN GREAT LAKES AND
ACROSS THE REGION MONDAY TO OFF NEW ENGLAND BY LATE MONDAY
NIGHT. ONLY A LIMITED AMOUNT OF MOISTURE IS AVAILABLE TO THIS
SUGGESTING AN INCH OR TWO OF SNOW...PERHAPS A BIT MORE WITH
SOME LAKE ENHANCEMENT ACROSS HERKIMER...HAMILTON...MAYBE 
FULTON COUNTIES. THAT IS FOLLOWED BY A BRIEF PAUSE ON TUESDAY
WITH A POSSIBILITY OF SOME LINGERING LAKE EFFECT SNOW ACROSS
THE NORTHWEST PART OF OUR AREA...WHILE FARTHER SOUTH AND EAST
CLOUDS MAY BREAK ENOUGH FOR SOME SUNNY INTERVALS...ESPECIALLY
IN THE MID HUDSON REGION OF NEW YORK. HIGHS TUESDAY WILL RANGE
FROM THE LOW 30S ACROSS THE ADIRONDACKS AND SOUTHERN VERMONT 
TO THE LOW 40S IN THE HUDSON VALLEY SOUTH OF ALBANY. 

MEANWHILE A MUCH STRONGER SYSTEM...SUPPORTED BY AN UPPER TROF...
MOVES FROM THE SOUTHERN ROCKIES TO THE PLAINS ON TUESDAY AND
TO THE MIDWEST TUESDAY NIGHT AS IT DEEPENS. AT THE SAME TIME 
A SURFACE LOW IS FORECAST TO DEVELOP NEAR CAPE HATTERAS. THESE
TWO SYSTEMS WILL BEGIN TO INFLUENCE OUR WEATHER LATE TUESDAY
NIGHT. THE ECM MODEL IS A LITTLE FASTER THAN THE GFS IN 
STARTING THE PRECIP. BOTH MODELS FEATURE A SOUTHEASTERLY 
LOW LEVEL JET WHICH WILL FEED WARMTH AND MOISTURE IN FROM
OFF THE GULF STREAM. THE STORM WILL START OUT AS SNOW...
MIX WITH AND TURN TO RAIN FROM ALBANY SOUTH AND EAST...
THEN TURN BACK TO SNOW AS COLDER AIR RETURNS. THIS STORM 
HAS THE POTENTIAL TO BRING A WARNING CATEGORY SNOWFALL TO
THE REGION FROM THE CATSKILLS...CAPITAL DISTRICT...AND 
BERKSHIRES NORTH...WITH THE HEAVIEST SNOWFALL FROM THE
CENTRAL ADIRONDACKS EAST INTO THE MOUNTAINS OF SOUTHERN
VERMONT. IT WILL ALSO GET QUITE BREEZY STARTING MIDDAY 
THURSDAY...WHICH COULD HAMPER SNOW REMOVAL EFFORTS...AS
THE STORM DEEPENS AND THE GRADIENT INCREASES BETWEEN IT 
AND HIGH PRESSURE OVER THE DEEP SOUTH. MUCH COLDER AIR
WILL BE BROUGHT INTO THE REGION FROM CENTRAL CANADA AS
THE STORM SLOWLY LIFTS NORTHEAST ACROSS THE MARITIMES
THURSDAY NIGHT WITH TEMPERATURES DIPPING INTO THE SINGLES
ACROSS THE ADIRONDACKS...THE LOW 20S IN THE HUDSON VALLEY
     AND THE TEENS ELSEWHERE. FRIDAY WILL BE COLD AND BLUSTERY
WITH LAKE EFFECT SNOW LIKELY FOR THE FIRST PART OF THE DAY
WHICH IS LIKELY TO MIGRATE NORTHWARD AS WINDS SHIFT AROUND
TO SSW BY EVENING...BUT BEFORE THEN WE MAY EXPERIENCE 
LONG LAKE AXIS PARALLEL WINDS...WHICH WOULD BE LIKELY 
TO FORM A BAND EXTENDING INTO HERKIMER...HAMILTON...
FULTON...AND POSSIBLY MONTGOMERY COUNTIES ON FRIDAY. 

FOR THE MOST PART...WE INITIALIZED THE GRIDS WITH GMOS.

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
HIGH AND MIDLEVEL CLOUDS HAVE OVERSPREAD THE REGION LAST EVENING
AS A FAST SOUTHERN STREAM FLOW MOVES UP THE EASTERN SEABOARD. 
CLOUDS WILL LOWER FROM SOUTH TO NORTH AFTER DAYBREAK THIS MORNING 
WITH MVFR CIG/VISBY SETTING IN AT KPOU SHORTLY BEFORE NOON WITH 
LIGHT SNOW AND MIST...AT KALB BY EARLY AFTERNOON...AND AT KGFL BY
LATE AFTERNOON. CONDITIONS ARE LIKELY TO DETERIORATE TO IFR SOUTH OF 
ALBANY BY LATE AFTERNOON...THEN IMPROVE SOME LATE IN THE EVENING AS 
THE STORM MOVES AWAY TO THE EAST. CONDITIONS WILL IMPROVE TO VFR 
AROUND 06Z SUNDAY. WINDS WILL BE LIGHT FROM THE NORTH OR CALM
AROUND DAYBREAK...THEN INCREASE TO BETWEEN 5 AND 8 KNOTS BY LATE 
MORNING...AND TO BETWEEN 6 AND 12 KNOTS BY LATE THIS EVENING. 

OUTLOOK...
SUN-TUE...VFR. NO SIG WX.
WED...MVFR. CHC -RASN.

&&

.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT 5 DAYS. RIVERS WILL
CONTINUE TO RECEDE FROM THE RAINFALL THURSDAY WITH SEVERAL DAYS OF
COLD WEATHER. THE MAIN PTYPE WILL BE SNOW FROM THE OCEAN LOW ON
SATURDAY WITH GENERALLY A TENTH TO FOUR TENTHS OF AN INCH OF
LIQUID EQUIVALENT.

A MORE INTENSE STORM WILL AFFECT THE REGION LATE TUESDAY NIGHT
INTO WEDNESDAY NIGHT. THIS STORM WILL BRING A MIX OF SNOW AND 
RAIN TO THE REGION...WITH MOSTLY SNOW FROM THE ALBANY AREA NORTH.
SOUTH OF THE ALBANY AREA THE STORM IS FORECAST TO START AS SNOW
WITH AN INCH OR TWO ACCUMULATION BEFORE IT MIXES WITH AND CHANGES
TO RAIN...WITH TOTALS UP TO AN INCH ACROSS OUR SOUTHERN ZONES. 
THIS WILL BRING ABOUT SIGNIFICANT WITHIN BANKS RISES ON THE 
RIVERS IN THIS AREA...INCLUDING THE LOWER PORTIONS OF THE 
HOUSATONIC ALONG WITH THE STILL...SHEPAUG...AND POMPERAUG
RIVERS IN CONNECTICUT AND THE TENMILE...RONDOUT...AND WAPPINGERS
IN NEW YORK STATE. FARTHER NORTH...AND WEST...THE COMBINATION
OF MORE SNOW AND LESS RAIN WOULD TEND TO RESULT IN LITTLE OR
NO EFFECT ON STREAMFLOWS. 

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...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR CTZ001-013.
NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR NYZ065-066.
MA...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR MAZ001-025.
VT...NONE.

&&

$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...SNYDER
LONG TERM...RCK
AVIATION...RCK
HYDROLOGY...RCK