FXUS61 KALY 231016
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
516 AM EST WED DEC 23 2009

.SYNOPSIS...
HIGH PRESSURE...CENTERED SOUTH OF HUDSON BAY...WILL DOMINATE OUR 
WEATHER INTO FRIDAY...WITH COLD AND MAINLY DRY WEATHER. A WEAK 
DISTURBANCE ALONG WITH A FLOW OF COLD AIR OVER LAKE ONTARIO WILL 
BRING CLOUDS AND SOME SNOW SHOWERS MAINLY NORTH AND WEST OF ALBANY 
TODAY. A LOW PRESSURE SYSTEM WILL MOVE NORTH FROM THE SOUTHERN 
PLAINS TOWARD THE WESTERN GREAT LAKES LATE IN THE WEEK. ANOTHER AREA 
OF LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE MID ATLANTIC REGION 
OVER THE WEEKEND. THIS COMPLEX WEATHER PATTERN WILL LIKELY BRING 
MIXED PRECIPITATION TO THE AREA OVER THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WE WILL BE DEALING WITH SOME LAKE EFFECT SNOW SHOWERS TODAY WITH
A CYCLONIC FLOW AROUND THE UPPER LOW MOVING SLOWLY ACROSS NORTHERN
NEW YORK INTO NEW ENGLAND. THIS WILL INTERACT WITH A SURFACE HIGH
UNDER AN UPPER RIDGE NORTH OF LAKE SUPERIOR TO CONTINUE TO DRAW 
COLD AIR OUT OF CENTRAL CANADA WHERE 850 HPA TEMPERATURES ARE 
MINUS 15 ALONG WITH MIXING IN VERY MOIST AND SOMEWHAT WARMER
MARITIME AIR FROM QUEBEC AND THE MARITIMES. TEMPERATURES UPWIND
OF THE LAKES WERE MOSTLY IN THE SINGLES AND THIS AIR WILL PICK
UP ADDITIONAL MOISTURE OFF LAKE ONTARIO AND PERHAPS EVEN A BIT
OFF OF GEORGIAN BAY. IT DOES APPEAR THE WINDS WILL HAVE ENOUGH OF
A NORTHERLY TILT TO NOT FOLLOW THE LONG AXIS OF THE LAKE...AND
FORM MULTIPLE BANDS RATHER THAN A SINGLE BAND. MUCH OF THE LAKE
EFFECT ACTIVITY WILL BE WEST OF OUR FORECAST AREA. BOTH NAM-12
AND GFS MODEL SOUNDINGS INDICATE MOISTURE IS VERY LIMITED SO
SNOWFALL EVERYWHERE EXCEPT A FEW SPOTS WILL BE QUITE LIGHT 
WITH THE AREAS MOST AFFECTED BEING THE UPPER MOHAWK VALLEY AND
THE NORTHWESTERN CATSKILLS INCLUDING THE SCHOHARIE VALLEY. SOME
SNOW SHOWERS ARE LIKELY TO MAKE IT ALL THE WAY DOWN TO THE CAPITAL
DISTRICT...AND THERE WILL PROBABLY ALSO BE SOME TERRAIN ENHANCED 
FLURRIES OR SNOW SHOWERS ACROSS THE HIGHER ELEVATIONS OF THE 
BERKSHIRES AND THE SOUTHERN GREEN MTNS. WITH LOTS OF CLOUDS 
IT WILL BE QUITE CHILLY...WITH HIGHS RANGING FROM THE UPPER TEENS
OVER THE ADIRONDACKS AND SOUTHERN VERMONT TO THE LOW 20S IN THE
CAPITAL DISTRICT...AND A BIT WARMER...NEAR 30...IN THE HUDSON 
VALLEY SOUTH OF ALBANY. USED A BLEND OF THE MAV/MOS AND THE
MET/MOS. 

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
BY EVENING...WINDS TAKE A MORE NORTHERLY TILT WHICH SHOULD BRING
ANY LAKE EFFECT SNOW IN OUR AREA TO A HALT...WITH WINDS VEERING
AROUND TO A NORTHEASTERLY DIRECTION DURING THE NIGHT. LOW LEVELS
CONTINUE QUITE MOIST BUT THE MOIST LAYER MAY BE THIN ENOUGH THAT
SOME BREAKS IN THE CLOUDS MAY OCCUR DURING THE NIGHTTIME HOURS...
AND PERHAPS A FEW RAYS OF SUNSHINE EARLY THURSDAY BEFORE HIGH 
CLOUDS AHEAD OF THE BIG STORM IN THE MISSISSIPPI VALLEY MOVE
IN. IT WILL NOT BE QUITE AS COLD TONIGHT...WITH LOWS FROM THE
UPPER SINGLES IN THE ADIRONDACKS TO THE MID TEENS IN THE CAPITAL
DISTRICT AND SOUTH.  

FOR THURSDAY...HIGH CLOUDS MOVE IN DURING THE DAY...AND WITH SOME
PARTIAL SUNSHINE...ESPECIALLY IN THE HUDSON VALLEY...TEMPERATURES
WILL RISE TO NEAR 30 ACROSS THE ADIRONDACKS AND HIGHER ELEVATIONS 
OF SOUTHERN VERMONT AND THE CATSKILLS AND TO THE MID 30S IN THE
HUDSON VALLEY.  

FOR CHRISTMAS EVE...IT WILL BE CLOUDY AND NOT QUITE AS COLD AS 
TONIGHT...WITH LOWS NEAR 10 IN THE ADIRONDACKS AND NEAR 20 IN THE 
HUDSON VALLEY.  

WENT WITH A BLEND OF THE MAV/MOS AND MET/MOS FOR HIGH AND LOW
TEMPERATURES. 

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS HAVE TRENDED LATER WITH ONSET OF PRECIPITATION NOW NOT 
EXPECTED UNTIL SATURDAY MORNING. LOOKING AT A DRY DAY WITH 
INCREASING CLOUDS FOR CHRISTMAS AND SEASONABLE TEMPERATURES.

STILL EXPECTING A WINTRY MIX OF PRECIPITATION THIS WEEKEND. COMPLEX 
STORM DEVELOPING. THE GFS AND ECMWF ARE IN GENERAL AGREEMENT MOVING 
LOW PRESSURE NORTHWARD ACROSS THE PLAINS AS SYSTEM BECOMES STACKED 
TOWARD THE WESTERN GREAT LAKES. HOWEVER...COMPLICATING MATTERS IS 
THE DEVELOPMENT OF SECONDARY LOW OVER THE MID ATLANTIC REGION 
SATURDAY INTO SATURDAY NIGHT. THE MODELS HAVE NOW TRENDED TO THE 
SECONDARY EVENTUALLY BECOMING THE DOMINANT OVER THE WEEKEND AND MOVE 
NORTHWARD ACROSS NEW ENGLAND.

AS THE PRIMARY LOW HEADS TOWARD THE WESTERN GREAT LAKES REGION 
WARMER AIR INITIALLY IS EXPECTED TO WORK ALOFT RESULTING IN A WINTRY 
MIX OF PRECIPITATION OVERSPREADING THE AREA SATURDAY MORNING. THE 
MODELS CONTINUE TO BRING WARM AIR TO THE SURFACE ALLOWING A CHANGE 
OVER TO PLAIN RAIN SATURDAY AFTERNOON PARTICULARLY SOUTH OF THE 
CAPITAL DISTRICT. THE ECMWF INDICATES THE RAIN COULD BE HEAVY. 
HOWEVER...THE THREAT FOR MORE WINTRY PRECIPITATION INCLUDING 
FREEZING RAIN MAY COME BACK SATURDAY NIGHT AS SURFACE TEMPERATURES 
DROP. UNCERTAINTY IN THE FORECAST IS RATHER HIGH AS ANY CHANGES IN 
THE DEVELOPMENT AND/OR STRENGTH OF THE SECONDARY LOW WILL HAVE A BIG 
IMPACT ON THE FORECAST/THERMAL PROFILE AND P-TYPE.

AS THE SYSTEM MOVES TO OUR NORTH...COLDER AIR WILL BE USHERED INTO 
THE REGION SUNDAY INTO EARLY NEXT WEEK.

WILL CONTINUE TO HIGHLIGHT THREAT OF A WINTRY MIX AND POSSIBLE HEAVY 
RAINFALL IN OUR HAZARDOUS WEATHER OUTLOOK.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
MAINLY VFR CONDITIONS EXPECTED THROUGH TAF PERIOD 06Z/THURSDAY.
CLOUDS WILL CONTINUE TO MOVE SOUTH ACROSS THE FORECAST AREA...AS
AN UPPER LEVEL LOW OVER NEW ENGLAND GRADUALLY MOVES SOUTHWARD.
MVFR CONDITIONS ARE POSSIBLE AT KGFL AND KALB DUE TO A PASSING
SNOW SHOWER. HAVE THIS POSSIBILITY INDICATED WITH A VICINITY
SHOWERS AND SCATTERED MVFR CLOUDS. OTHERWISE...NORTHWESTERLY FLOW
CONTINUES WITH WINDS THE STRONGEST AT KALB AS THEY ARE ENHANCED
DOWN THE MOHAWK VALLEY. GUSTS AT KALB OF 20 TO 25 KNOTS EXPECTED. 

OUTLOOK...
THU-FRI...VFR...NO SIG WX.
FRI NGT...VFR DETERIORATING TO MVFR-IFR LATE AS A WINTRY MIX MOVES
IN.
SAT-SAT NGT...MVFR-IFR...WITH A WINTRY MIX CHANGING TO PLAIN RAIN
AT KPOU BY LATE MORNING...AT KALB BY EARLY AFTERNOON AND POSSIBLY
AT KGFL DURING THE AFTERNOON. COLDER AIR MOVES BACK IN SAT NIGHT
CHANGING PCPN TO SNOW. 
SUN...VFR...MVFR POSSIBLE WITH A CHC -SHRA/-SHSN.

&&

.HYDROLOGY...
NOTE...THE WATERFORD GAGE /WTFN6/ IS EXPERIENCING ICE ON THE SENSOR 
AND IS RESULTING IN INACCURATE READINGS.  RFC/USGS AND WATERFORD 
POLICE DEPARTMENT HAVE BEEN CONTACTED SINCE NO FLOODING NOR ICE JAMS 
ARE OCCURRING.  THE AHPS WEB PAGE HAS BEEN NOTATED AT THIS TIME.

THE MONITORING EQUIPMENT ON THE MOHAWK AT LITTLE FALLS HAS ALSO
BECOME FROZEN AND IT IS INOPERATIVE. 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 MANY RIVERS. ACCUMULATING ICE MAY CAUSE SOME RIVER LEVELS TO RISE 
EVEN THOUGH FLOWS CONTINUE TO DIMINISH.

STARTING MIDDAY CHRISTMAS DAY...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
THE RAIN COULD BE HEAVY AT TIMES ON SATURDAY. THIS WOULD BRING 
ABOUT SIGNIFICANT INCREASES IN RIVER FLOWS...WHICH IN TURN COULD
BREAK SOME OF THE ICE LOOSE. ASIDE FROM BACKUPS OR SURGES FROM
ICE JAMS...NOT ENOUGH RUNOFF IS EXPECTED TO CAUSE FLOODING.  

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