FXUS61 KALY 241559
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1059 AM EST THU DEC 24 2009

.SYNOPSIS...
COLD CANADIAN HIGH PRESSURE WILL SHIFT EASTWARD ACROSS THE REGION
TODAY AND TONIGHT AND SHOULD DOMINATE OUR WEATHER INTO CHRISTMAS.
A STRONG LOW PRESSURE SYSTEM WILL MOVE NORTH FROM THE SOUTHERN
PLAINS TOWARD THE WESTERN GREAT LAKES INTO THIS WEEKEND WITH ITS
ASSOCIATED FRONTAL BOUNDARY MOVING TOWARD OUR REGION. A SECONDARY 
AREA LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THIS BOUNDARY 
SATURDAY. THIS SCENARIO WILL BRING MIXED PRECIPITATION TO THE AREA 
OVER THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1050 AM EST...SFC HIGH PRESSURE CONTINUES TO RIDGE IN FROM
SOUTH OF HUDSON BAY. THE SATELLITE PICTURE DEPICTS PLENTY OF LOW
CLOUDS NORTH OF THE MID HUDSON RIVER VALLEY. THE 12Z KALB SOUNDING
SHOWS MOISTURE TRAPPED BENEATH A STEEP INVERSION AT 800 HPA.
SUBSIDENCE FROM THE HIGH SHOULD BEGIN TO ERODE THE INVERSION.
HOWEVER...THE CLOUDS WILL LIKELY BREAK UP FROM THE CAPITAL REGION
NORTH IN THE EARLY TO MID AFTERNOON. WE WILL RETREND THE FCST TO
MOSTLY CLOUDY...EXCEPT SOUTH OF THE CAPITAL REGION AND THE
BERKSHIRES WHERE IT WILL BE PARTLY TO MOSTLY SUNNY. WE ALSO
LOWERED MAX TEMPS FROM THE CAPITAL REGION NORTH WITH U20S TO L30S
DOMINATING. THESE ARE CLOSER TO THE NAM MOS TEMPS.

FROM PREVIOUS FORECAST DISCUSSION...
HIGH CLOUDS WILL BEGIN TO STREAM INTO THE REGION FROM AROUND THE
NORTH SIDE OF THE RIDGE THIS AFTERNOON. THE CLOUDS WILL THICKEN
SOME TONIGHT...WHICH SHOULD PRETTY MUCH BLOCK OUTGOING
RADIATION...SO LOW TEMPERATURES TONIGHT WILL BE ABOUT 5 DEGREES
WARMER THAN EARLY THIS MORNING...AND RANGE FROM THE LOW TEENS TO
AROUND 20...A FEW DEGREES ABOVE THE SEASONAL NORM. AGAIN...USED A
BLEND OF THE MAV AND MET MOS.

CHRISTMAS DAY WILL LIKELY FEATURE MILKY SUNSHINE THROUGH A
DECK OF HIGH AND MIDLEVEL CLOUDS FOR MUCH OF THE DAY...WITH
HIGHS IN THE MID 30S. WARM AND MOIST AIR WILL BEGIN TO STREAM
INTO THE REGION WITH A LOW LEVEL JET OFF THE EAST COAST WITH
OVERRUNNING BRINGING ABOUT A SLIGHT CHANCE OF PRECIPITATION
IN OUR SOUTHERN ZONES WHICH WOULD TAKE THE FORM OF A WINTRY
MIX OF SNOW...SLEET...AND RAIN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
WINTRY MIX OF PRECIPITATION EXPECTED THIS WEEKEND...

NO BIG CHANGES IN THE MODELS...BUT UNCERTAINTY IN THE DETAILS 
REMAINS HIGH. COLD CANADIAN HIGH PRESSURE EXTENDS SOUTHWARD ACROSS 
THE GREAT LAKES REGION INTO THE NORTHEAST. THE RIDGE WILL SHIFT 
EASTWARD TODAY AND TONIGHT AND ACROSS NEW ENGLAND FRIDAY. A LARGE 
LOW PRESSURE SYSTEM OVER TEXAS WILL MOVE NORTHWARD TOWARD THE MID 
WEST THE REST OF THE WEEK. ITS ASSOCIATED FRONTAL BOUNDARY WILL PUSH 
NORTHERLY ACROSS THE EASTERN UNITED STATES. THE MODELS CONTINUE TO 
INDICATE A SECONDARY LOW WILL FORM ALONG THE FRONTAL BOUNDARY 
SATURDAY OVER THE MID ATLANTIC REGION COMPLICATING THE FORECAST.  

COLD AIR DAMMING WILL OCCUR ACROSS THE REGION WITH WARMER AIR 
MOVING IN ALOFT AS PRECIPITATION SPREADS NORTHWARD INTO THE REGION. 
A MIXTURE OF SNOW...SLEET AND OR FREEZING RAIN WILL OVERSPREAD THE 
REGION LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH A CHANGE OVER TO 
PLAIN RAIN STILL EXPECTED ACROSS MUCH OF THE FORECAST AREA SATURDAY 
AFTERNOON INTO THE EVENING. ALSO...THERE STILL IS THE POTENTIAL FOR 
THE RAIN TO BE HEAVY AT TIMES SATURDAY NIGHT PARTICULARLY SOUTH OF 
THE CAPITAL DISTRICT.

AS THE SYSTEM MOVES TO OUR NORTH...COLDER AIR WILL BE USHERED BACK 
INTO THE REGION SATURDAY NIGHT CHANGING THE PRECIPITATION BACK TO 
SNOW WITH THE THREAT OF FREEZING RAIN ACROSS THE NORTHERN COUNTRY 
AND SOUTHERN VERMONT BEFORE THE PRECIPITATION TAPERS OFF.

AT THIS TIME...IT APPEARS WINTER WEATHER ADVISORIES WILL BE NEEDED 
TO HANDLE THIS STORM WITH ICE ACCUMULATIONS OF A TENTH TO A QUARTER 
OF AN INCH POSSIBLE. WILL CONTINUE TO HIGHLIGHT THREAT OF THE WINTRY
MIX AND POSSIBILITY HEAVY RAINFALL IN OUR HAZARDOUS WEATHER
OUTLOOK.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY WILL BE RELATIVELY MILD COMPARED TO OUR RECENT WEATHER WITH
TEMPERATURES IN THE 30S...WITH LOWER 40S POSSIBLE IN THE MID
HUDSON VALLEY...ALONG WITH CHANCES FOR RAIN AND SNOW SHOWERS.
HOWEVER...COLD WEATHER IS EXPECTED AS WE CLOSE OUT THE YEAR. A
MUCH COLDER AIRMASS WILL BE USHERED INTO REGION EARLY NEXT WEEK
WITH THE PASSAGE OF A COLD FRONT MONDAY. BRISK WESTERLY WINDS WILL
ONLY MAKE IT FEEL EVEN COLDER. ALONG WITH THE COLD AIR WILL COME
SCATTERED SNOW SHOWERS WITH LAKE ENHANCEMENT.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE REGION CONTINUES TO BE COVERED WITH A DECK OF LOW STRATUS 
AND STRATOCU RESULTING FROM COLD MOIST AIR TRAPPED IN AN INVERSION 
WITH SOME ADDITIONAL MOISTURE COMING FROM THE GREAT LAKES. CLOUD 
BASES ARE GENERALLY 2000-3000 FEET ASL...THUS CIGS ARE MOSTLY 
MVFR IN THE HUDSON AND MOHAWK VALLEYS WITH AREAS OF IFR ACROSS
THE HIGHER TERRAIN. WINDS WERE LIGHT AND VARIABLE WITH SOME 
SITES CALM. THE LOW CLOUD DECK EXTENDED TO KMSV...KPOU...AND 
KHFD. SOUTH OF THESE SITES SKIES WERE CLEAR. VISIBILITIES WERE
BETTER THAN 6 MILES.  

WITH THE SUN AT A LOW ANGLE...CONDITIONS WILL BE SLOW TO IMPROVE
THIS MORNING. HOWEVER BY MIDDAY THE CLOUD DECK SHOULD START TO 
BECOME SCATTERED. IN THE MEANTIME A LAYER OF HIGH CLOUDS WILL 
BEGIN TO STREAM IN FROM THE NORTHWEST AROUND THE NORTH SIDE OF
THE UPPER RIDGE. WINDS TODAY WILL GENERALLY BE NORTH AROUND 5 
KNOTS...WITH A BIT OF A WESTWARD TILT AT ALBANY DUE TO THE 
TERRAIN.  

BY EVENING...THE REGION SHOULD BE UNDER A BROKEN TO OVERCAST 
DECK OF HIGH CLOUDS WITH THE WINDS CALM...OR NEARLY SO. THE
DECK WILL START TO THICKEN AND LOWER SOUTH OF ALBANY LATER
TONIGHT...BUT THE CIG SHOULD REMAIN WELL ABOVE VFR MINIMUMS. 

OUTLOOK...
FRIDAY...VFR IN THE MORNING. SLIGHT CHC -RASNPL SOUTH IN THE PM.
FRI NGT...DETERIORATING TO MVFR AS A WINTRY MIX MOVES IN. 
SAT-SAT NGT...MVFR-IFR...WITH A WINTRY MIX. A CHANGE OVER TO PLAIN 
RAIN...AT KPOU MID TO LATE MORNING...AT KALB BY EARLY AFTERNOON AND 
AT KGFL EARLY IN THE EVENING.
SUN...VFR...MVFR POSSIBLE WITH CHC SHRA/-SHSN.
MON...VFR...MVFR POSSIBLE WITH CHC -SHSN.

&&

.HYDROLOGY...
NOTE...AUTOMATED READINGS FROM THE WATERFORD GAGE /WTFN6/ HAVE
BEEN SUSPENDED DUE TO MALFUNCTIONING EQUIPMENT. A LIMITED NUMBER
OF OBSERVATIONS ADAPTED FROM A NEARBY GAGE ARE BEING USED TO 
MONITOR THE RIVER IN THIS AREA. THE AHPS WEB PAGE HAS BEEN NOTATED 
AT THIS TIME.

THE MONITORING EQUIPMENT ON THE MOHAWK AT LITTLE FALLS WAS 
WORKING AGAIN AFTER HAVING BEEN FROZEN THE LAST FEW DAYS. GAGES
ON THE MOOSE RIVER AT MCKEEVER AND ON THE SCHOHARIE CREEK AT 
PRATTSVILLE ARE WORKING BUT READING ABOUT TWO FEET HIGHER DUE 
TO THE EFFECT OF ICE IN THE RIVER. 

COLD WEATHER WILL CONTINUE ACROSS THE REGION WITH A GRADUAL WARMING
TREND THROUGH CHRISTMAS DAY. DURING THIS TIME...TEMPERATURES ARE 
FORECAST TO AVERAGE WELL BELOW FREEZING ACROSS THE ENTIRE FORECAST 
AREA...WHICH WILL LIKELY RESULT IN THE FORMATION OF ADDITIONAL ICE 
ON RIVERS. ACCUMULATING ICE MAY CAUSE SOME RIVER LEVELS TO RISE 
EVEN THOUGH FLOWS CONTINUE TO DIMINISH.

STARTING CHRISTMAS NIGHT...THE PRECIP SHIELD FROM THE STORM IN
THE MIDWESTERN STATES WILL BEGIN TO AFFECT US WITH A MIX OF
SNOW... SLEET...AND RAIN. LITTLE...IF ANY...MELTING IS EXPECTED TO
TAKE PLACE UNTIL SATURDAY WHEN WARMER AIR BEGINS TO MIX DOWN TO
THE SURFACE AND BRING TEMPERATURES INTO THE UPPER 30S AND LOW 40S
FROM THE MOHAWK VALLEY SOUTH. MUCH OF THIS AREA HAS RELATIVELY
LITTLE SNOW ON THE GROUND...AND WITH A FLOW OF WARM AIR OFF THE
OCEAN THERE IS A POSSIBILITY OF SUBSTANTIAL RAIN SATURDAY NIGHT.
THIS COULD BRING ABOUT SIGNIFICANT INCREASES IN RIVER FLOWS...
WHICH IN TURN COULD BREAK SOME OF THE ICE LOOSE.

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...IAA
NEAR TERM...WASULA/RCK
SHORT TERM...IAA
LONG TERM...IAA
AVIATION...RCK
HYDROLOGY...RCK