FXUS61 KALY 251333
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
833 AM EST FRI DEC 25 2009

.SYNOPSIS...
A LARGE AND POWERFUL LOW PRESSURE SYSTEM OVER THE MID WEST WILL
MOVE LITTLE TODAY AND TONIGHT. THIS STORM WILL BEGIN TO WEAKEN AND
MOVE EASTWARD ACROSS THE GREAT LAKES REGION OVER THE WEEKEND. IN
THE MEANTIME...A SECONDARY AREA LOW PRESSURE IS EXPECTED TO
DEVELOP OVER THE MID ATLANTIC REGION OVERNIGHT...THEN HEAD
NORTHEAST. MIXED PRECIPITATION...MAINLY FREEZING RAIN...WILL
OVERSPREAD THE AREA LATE TONIGHT AND SATURDAY MORNING...WITH A
CHANGE OVER TO PLAIN RAIN EXPECTED ACROSS MUCH OF THE AREA DURING
THE DAY SATURDAY. COLDER AIR WILL FILTER BACK INTO THE REGION AS
THE LOWS MOVE NORTHWARD. AN EVEN COLDER AIRMASS WILL BE USHERED IN
WITH THE PASSAGE OF COLD FRONT MONDAY NIGHT.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE UPDATED THE FORECAST FOR AREAS OF FREEZING FOG THIS MORNING
AS VISIBILITIES HAVE BEEN DOWN TO 1 1/2SM IN PLACES AND ALSO HAVE
ADDED A CHANCE OF LIGHT SNOW AS VERY LIGHT PRECIPITATION HAS BEEN
FALLING IN SOME AREAS WHICH IS NOT BEING DETECTED VERY WELL BY THE
KENX WSR-88D. THESE CONDITIONS ARE EXPECTED TO LAST THROUGH THE
MORNING WITH GRADUAL IMPROVEMENT THIS AFTERNOON.

THE FOLLOWING IS FROM THE PREVIOUS DISCUSSION ORIGINALLY ISSUED
AT 506 AM EST...STUBBORN LOW LEVEL CLOUDS ARE TRAPPED BENEATH A
STRONG INVERSION. PLUS HAVE HIGH LEVEL CLOUDS STREAMING IN. LOW
CLOUDS MAY ERODE TODAY. OTHERWISE...EXPECTING SEASONABLE
TEMPERATURES...IN THE 30S...AND DRY WEATHER THROUGH THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
ICE ACCUMULATIONS OF ONE TENTH TO ONE QUARTER OF AN INCH ARE 
POSSIBLE...WITH THE HIGHER ACCUMULATIONS EXPECTED WEST OF THE
HUDSON RIVER.

COMPLEX SITUATION FOR TONIGHT THROUGH SATURDAY NIGHT....WITH MODELS 
IN GENERAL AGREEMENT. POWERFUL STORM CLOBBERING THE CENTRAL PORTION 
OF THE COUNTRY WILL IMPACT THE MID ATLANTIC AND NORTHEAST ALSO. THE 
STORM IS EXPECTED TO WOBBLE OVER THE MID WEST TODAY AS IT BECOMES 
VERTICAL STACKED. HOWEVER...TONIGHT IT SHOULD BEGIN TO WEAKEN THEN 
HEAD EASTWARD OVER THE WEEKEND. THE MODELS CONTINUE TO DEVELOP A 
SECONDARY LOW OVER THE SOUTHEAST NEAR THE COAST BEGINNING TODAY AND 
HEAD IT NORTHEAST ALONG THE COAST. ALL THAT SAID...LOOKING AT THE 
MODEL SOUNDINGS THIS IT SHAPING UP TO BE MORE OF A FREEZING RAIN 
EVENT THAN A MIXED EVENT....EVEN FROM THE ONSET. ICE ACCUMULATIONS 
ARE EXPECTED TO BE ADVISORIES LEVELS. PRECIPITATION OVERSPREADS THE 
AREA FROM SOUTHWEST TO NORTHEAST LATER THIS EVENING INTO SATURDAY 
MORNING.     

HAVE POSTED FREEZING RAIN ADVISORY FOR MOST OF FORECAST AREA.
GROUP ONE...THE MID HUDSON VALLEY...CENTRAL AND SOUTHERN TACONICS 
AND LITCHFIELD COUNTY. GROUP TWO...THE EASTERN CATSKILLS...MOHAWK 
VALLEY...UPPER HUDSON VALLEY INCLUDING THE CAPITAL DISTRICT...THE 
BERKSHIRES. THE REASON FOR THE SPLIT IS THE ONSET TIME OF THE 
FREEZING RAIN AND CHANGE OVER TO PLAIN RAIN IN SATURDAY.

ALSO HAVE POSTED A WINTER WEATHER ADVISORY FOR THE SOUTHERN 
ADIRONDACKS WHERE SLEET IS MORE LIKELY TO MIX IN WITH THE FREEZING 
RAIN OVERNIGHT INTO SATURDAY. ALSO...SOME OF THIS AREA MAY NEVER 
ACTUALLY SEE A CHANGE OVER TO PLAIN RAIN SATURDAY AFTERNOON/EVENING 
OR IT MIGHT BE RATHER SHORT-LIVED...SO MADE TIME OF ADVISORY GO 
THROUGH SATURDAY NIGHT. 

HAVE NOT POSTED ANY ADVISORIES FOR SOUTHERN VERMONT SINCE ONSET IS 
NOT EXPECTED UNTIL SATURDAY MORNING AND WOULD BE THIRD PERIOD 
ADVISORY. HAVE HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK.  

STRONG SOUTHEASTERLY LOW LEVEL JET...50 TO 70 KNOTS...FORECAST TO 
MOVE ACROSS THE REGION SATURDAY AND SATURDAY NIGHT...BRINGING IN THE 
WARMER AIR. THE HIGHER TERRAIN EAST OF ALBANY COULD HAVE WINDS GUSTS
REACHING ADVISORY LEVEL...UP TO 50 MPH...SO HAVE CONTINUE TO 
HIGHLIGHT THIS THE HAZARDOUS WEATHER OUTLOOK.

PRIMARY LOW WEAKENS OVER THE GREAT LAKES REGION WITH SOME 
STRENGTHENING OF THE SECONDARY AS IT HEADS UP THE NEW ENGLAND COAST 
SUNDAY. THE LINGERING PRECIPITATION WILL COME TO AN END. MILD 
TEMPERATURES EXPECTED WITH 40S UP THE HUDSON RIVER VALLEY AND 30S IN 
THE MOHAWK VALLEY AND ACROSS THE HIGHER TERRAIN. COLDER MORE 
SEASONABLE AIR WILL FILTER IN SUNDAY NIGHT.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
THE GFS AND ECMWF BOTH INDICATE WE ARE IN FOR ANOTHER COLD SPELL
FOR MUCH OF THIS PERIOD AS A SHARP 500 HPA TROF MOVES ACROSS THE
REGION MONDAY AND OPENS THE DOOR TO THE ARCTIC FREEZER. 850 HPA
TEMPS PLUNGE TO BETWEEN MINUS 20 AND MINUS 26 BY TUESDAY MORNING
BEFORE RECOVERING TO MINUS 16 WEDNESDAY MORNING AND MINUS 10 ON  
THURSDAY. A FRONTAL SYSTEM MONDAY WILL BRING ABOUT THE POSSIBILITY
OF SOME SNOW AS IT SWEEPS ACROSS THE AREA MONDAY EVENING...WITH 
LAKE EFFECT SNOW IN ITS AFTERMATH AS THE COLD AIR POURS IN...
AND AGAIN WE MAY HAVE WIND CHILL ISSUES AS WELL. THE SURFACE HIGH
WILL MOVE ACROSS THE REGION THURSDAY.

THE NEXT CHALLENGE IN THE MAKING IS NEW YEAR/S EVE. A LOW IS 
FORECAST TO MOVE ACROSS SOUTHEASTERN CANADA AND WEAKEN OVER THE
REGION WHILE A SECOND STORM BECOMES ORGANIZED NEAR CAPE HATTERAS
AND THEN MOVES EAST INTO THE ATLANTIC.  MODELS CURRENTLY SUGGEST
WE MAY HAVE A NUISANCE TYPE SNOW EVENT...JUST ENOUGH TO PUT A 
FRESH FROSTING ON THE AREA...AS THE SOUTHERN STORM WILL CUT OFF
THE MOISTURE. BUT A LOT CAN CHANGE BETWEEN NOW AND THEN. AT 
THIS TIME...NO MAJOR STORMS...AND TEMPS FOR THE PERIOD 5 DEGREES
ABOVE NORMAL FOR MONDAY...BUT THEN 5 TO 10 DEGREES BELOW NORMAL
FOR THE REST OF THE WEEK.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
A STRATUS DECK...A RESULT OF COLD AIR TRAPPED BELOW AN INVERSION...
EXTENDS FROM THE CHAMPLAIN VALLEY SOUTH DOWN THE HUDSON VALLEY TO 
LONG ISLAND...AND ALSO UP THE MOHAWK VALLEY TO ROME AND UTICA. 
OVER THE HIGHER TERRAIN SKIES WERE MOSTLY CLEAR. THE VISIBILITY 
WAS BELOW A MILE AT KDDF AND KPSF...AND DOWN TO 6 MILES AT KGFL
AND KALB. CIGS WERE IFR/LIFR EARLY THIS MORNING UNDER THE STRATUS
DECK. WINDS WERE CALM OR LIGHT FROM THE NORTHEAST. 

THE STRATUS DECK IS LIKELY TO PERSIST MOST OF THE MORNING WITH 
CIGS GRADUALLY IMPROVING TO MVFR...THEN HOPEFULLY BECOMING VFR 
FOR A FEW HOURS THIS AFTERNOON...BEFORE THE AIR NEAR THE SURFACE
COOLS AND THE LOW DECK RETURNS. GIVEN WHAT HAPPENED THURSDAY...A 
POSSIBILITY EXISTS THAT THE LOW CLOUDS MAY ONLY GO BROKEN THIS 
AFTERNOON. 

PRECIPITATION...IN THE FORM OF FREEZING RAIN...IS EXPECTED TO 
MOVE INTO THE KPOU AREA STARTING AROUND 02Z. IT WILL START AS
SLEET AND FREEZING RAIN AROUND 05Z AT KALB AND AROUND 07Z AT 
KGFL...WITH THE SLEET ENDING AROUND 10Z. CIGS ARE EXPECTED TO
DETERIORATE TO IFR DURING THE LATE NIGHT HOURS...STARTING AT 
KPOU AROUND 09Z AND AN HOUR OR TWO LATER FARTHER NORTH.

OUTLOOK...
SAT-SAT NGT...MVFR-IFR...WITH A WINTRY MIX MAINLY FREEZING RAIN. A
CHANGE OVER TO RAIN...AT KPOU MID TO LATE MORNING...AT KALB BY
EARLY AFTERNOON AND AT KGFL DURING THE AFTERNOON POSSIBLY CHANGING
BACK TO FREEZING RAIN AND OR SLEET AT NIGHT.
SUN...VFR...MVFR POSSIBLE WITH CHC -SHRA/-SHSN. 
MON...VFR...MVFR POSSIBLE WITH CHC -SHSN.
TUE...VFR...NO SIG WX.

&&

.HYDROLOGY...
NO HYDRO PROBLEMS THROUGH FRIDAY. THEN...THE NEXT SYSTEM WILL BRING 
A POTPOURRI MIX OF PRECIPITATION STARTING LATE FRIDAY NIGHT OR EARLY 
SATURDAY. IT LOOKS LIKE RAIN WILL BE THE PRIMARY PRECIPITATION TYPE 
FROM ALBANY SOUTHWARD. UP TO 1.5 INCHES IS POSSIBLE ACROSS OUR 
DACKS/LITCHFIELD HILLS AND BERKS. THIS MIGHT BE ENOUGH TO PRODUCE 
SOME EXCESSIVE RUNOFF FROM MELTING SNOW (WITH A WATER EQUIVALENT OF 
GENERALLY AROUND AN INCH). SOME SIGNIFICANT RISES ARE POSSIBLE ON 
THE HOUSATONIC BASIN...THE HOOSIC...RONDOUT CREEK...WAPPINGERS 
CREEK...AND MAYBE THE SCHOHARIE AND ESOPUS. A SIGNIFICANT INCREASE
IN FLOW COULD CAUSE SOME OF THE ICE TO BREAK UP...MOVE...AND 
POSSIBLY JAM. IT DOES NOT APPEARS THERE WILL BE ENOUGH RUNOFF FOR
FLOODING UNLESS ICE JAMS FORM AND BLOCK THE CHANNEL. 

NORTH AND WEST OF THE ALBANY AREA...MORE MIXED PRECIPITATION AND
COLDER TEMPERATURES SHOULD REDUCE SNOWMELT...AND RUNOFF SHOULD BE
MINIMAL.

WE WILL CONTINUE TO MONITOR THE SITUATION AS THE EVENT NEARS.

AFTER THE SYSTEM WINDS DOWN ON SUNDAY...IT WILL BE MAINLY DRY INTO 
EARLY NEXT WEEK. IT WILL TURN COLDER SO THAT PRECIPITATION SHOULD
COME AS SNOW. TEMPERATURES ARE FORECAST TO DROP BELOW FREEZING
SUNDAY NIGHT. LITTLE IF ANY MELTING WILL OCCUR MONDAY AFTERNOON 
AND TEMPERATURES WILL AVERAGE WELL BELOW FREEZING FOR THE REST OF
THE 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...FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO NOON EST 
     SATURDAY FOR CTZ001-013.
NY...FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST 
     SATURDAY FOR NYZ038>041-043-047>054-058-063-083-084.
     FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO NOON EST 
     SATURDAY FOR NYZ059>061-064>066.
     WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 6 AM EST 
     SUNDAY FOR NYZ032-033-042-082.
MA...FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST 
     SATURDAY FOR MAZ001-025.
VT...NONE.

&&

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