FXUS61 KALY 110901
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
401 AM EST FRI DEC 11 2009
.SYNOPSIS...
DEEP LOW PRESSURE WILL CONTINUE MOVING NORTHEAST ACROSS EASTERN
CANADA THROUGH TODAY. LARGE ARCTIC HIGH PRESSURE WILL SETTLE IN TO OUR
SOUTH. THE RESULT WILL BE STRONG AND GUSTY WESTERLY WINDS
CONTINUING. AS THE COLDER AIR MOVES ACROSS THE RELATIVELY WARMER
WATER OF LAKE ONTARIO...LAKE EFFECT SNOW WILL CONTINUE INTO EARLY
SATURDAY IMPACTING THE WESTERN ADIRONDACKS WITH SIGNIFICANT
SNOWFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LAKE EFFECT SNOW EVENT WILL CONTINUE TODAY IN NORTHERN HERKIMER
COUNTY...NOSING JUST INTO HAMILTON COUNTY...WITH NEAR BLIZZARD
CONDITIONS AT TIMES WITH THE BLOWING SNOW AND MULTIPLE INCHES PER
HOUR AT TIMES. MEAN WIND FLOW THROUGH THE BOUNDARY LAYER SHOULD
BEGIN TO TREND TO MORE WESTERLY THROUGH THE DAY...SLOWLY SHIFTING
THE LAKE EFFECT BAND SOUTH...BUT NOT MUCH.
OUTSIDE OF THE MAIN LAKE EFFECT BAND OF SNOW...SOME ISOLATED TO
SCATTERED SNOW SHOWER ACTIVITY IS EXPECTED ALONG AND NORTH OF THE
MOHAWK VALLEY INTO SOUTHERN VT. SOME ENHANCED ACTIVITY IS POSSIBLE
IN THE SOUTHERN GREENE MOUNTAINS. DOWNSLOPE FLOW WILL HELP VALLEY
AREAS SEE INTERVALS OF CLOUDS AND SUN...WHILE HIGHER ELEVATIONS
WILL BE MOSTLY CLOUDY. COLD ADVECTION CONTINUING...AND BASED ON
BOUNDARY LAYER TEMPERATURES AND MIXING POTENTIAL...HIGHS IN THE
20S MANY AREAS TODAY...NEAR 30 POU AND NW CT. WINDS WILL CONTINUE
TO BE GUSTY...BRINGING WIND CHILLS INTO THE TEENS AND SINGLE
NUMBERS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
MEAN WIND FLOW THROUGH THE BOUNDARY LAYER SLOWLY TRENDS TO MORE
WESTERLY AND WEST NORTHWESTERLY TONIGHT...SO THE LAKE EFFECT BAND
WILL CONTINUE TO SLOWLY SHIFT INTO CENTRAL HERKIMER AND HAMILTON
COUNTIES. THE DEPTH OF THE MOISTURE AND INSTABILITY JUST BEGINS TO
GET MORE SHALLOW TOWARD MORNING...BUT STILL...LOTS OF SNOW...WIND
AND DRIFTING IN AREAS AFFECTED BY THE SNOW BAND. SOME SCATTERED
SNOW SHOWER ACTIVITY WILL BEGIN TO EXTEND DOWN THE MOHAWK VALLEY
AS WELL...AND THE SOUTHERN GREENE MOUNTAINS COULD CONTINUE TO SEE
ENHANCES SNOW SHOWER ACTIVITY. WINDS WILL STILL BE BREEZY IN MANY
AREAS...AND WITH LOWS IN THE TEENS AND SINGLE NUMBERS...WIND
CHILLS WILL BE AROUND ZERO AT TIMES IN THE VALLEYS...AND 5 TO 15
BELOW IN THE MOUNTAINS.
ON SATURDAY...THE MEAN LOW LEVEL WIND FLOW WEAKENS CONSIDERABLY
THROUGH THE DAY...AND THE DEPTH OF THE INSTABILITY AND MOISTURE
BECOMES TOO SHALLOW BY AFTERNOON TO SUPPORT AN ORGANIZED LAKE
EFFECT SNOW BAND. SOME WEAK WARM ADVECTION BEGINS BY AFTERNOON AS
THE LOW LEVEL RIDGE AXIS BUILDS OVER OUR REGION...AND BEGINS TO
BUILD EAST. HIGHS SATURDAY IN THE 20S TO LOWER 30S. WEAK WARM
ADVECTION WILL CONTINUE SATURDAY NIGHT...BUT LOW LEVEL RIDGING
STILL PROXIMATE ENOUGH FOR LIGHT WINDS AND MOSTLY CLEAR SKY MOST
OF THE NIGHT. WITH SNOW COVER...TEMPERATURES FALL INTO THE TEENS
WITH SOME SINGLE NUMBERS IN THE ADIRONDACKS. SOME HIGH CLOUDS WILL
SPREAD OVER THE REGION TOWARD SUNRISE AHEAD OF THE NEXT SYSTEM.
CURRENT SYSTEM COMING ASHORE IN SOUTHWESTERN U.S. IS PREDICTED TO
DAMPEN OUT TO SOME DEGREE AS IT CROSS THE NATION...AND INCREASING
CONSENSUS FROM GUIDANCE THAT OUR REGION WILL SEE SOME EFFECTS FROM
THIS SYSTEM ON SUNDAY AND SUNDAY NIGHT. STRONG CONFLUENT FLOW
ACROSS NORTH AMERICA AND CURRENT ORIGINS IN RELATIVELY DATA SPARSE
EASTERN PACIFIC...SUGGESTS THAT MANY OF THE FINE DETAILS SUCH AS
TIMING...PRECIPITATION AMOUNTS AND NORTHERN EXTEND OF PRECIPITATION
SHIELD WILL NOT BE KNOWN UNTIL THE EVENT IS CLOSER.
HOWEVER...A QUICK SHOT OF STRONG WARM ADVECTION...FRONTOGENESIS
AND ISENTROPIC LIFT SUGGESTS ACCUMULATING SNOW IN MANY AREAS
SUNDAY AND SUNDAY NIGHT. SOME VALLEY AREAS FROM THE CAPITAL
DISTRICT AND SOUTHERN VT AND POINTS SOUTH COULD SEE A MIX WITH RAIN
AT TIMES LATE IN THE EVENT BEFORE PRECIPITATION CHANGES TO
SCATTERED SNOW SHOWER ACTIVITY. HIGHS SUNDAY IN THE LOWER TO MID
30S...WITH SOME UPPER 30S MID HUDSON VALLEY AND IN DDH/AQW
AREA...SOME UPPER 20S ADIRONDACKS.
SYSTEM CURRENTLY TIMED TO EXIT SUNDAY NIGHT...BUT ONLY WEAK COLD
ADVECTION BEHIND THIS SYSTEM...AND LINGERING CLOUD COVER AND
MOISTURE WILL PREVENT TEMPERATURES FROM FALL TOO MUCH. LOWS IN THE
20S TO AROUND 30...AROUND 20 ADIRONDACKS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
MON-MON NT...MODELS DEPICT A WEAK HIGH PRESSURE RIDGE TO SLIDE E
ACROSS THE REGION ON MON...BEFORE THE NEXT SYSTEM APPROACHES FROM
THE W. THERE IS A SLIGHT CHC FOR SNOW SHOWERS/FLURRIES EARLY ACROSS
FAR NW AREAS...OTHERWISE EXPECT A MAINLY DRY DAY. HOWEVER...LOW
CLOUDS MAY HANG TOUGH...AS ABUNDANT MOISTURE MAY REMAIN TRAPPED
BENEATH LOW SUBSIDENCE INVERSION. EXPECT MAX TEMPS TO REACH 40-45
WITHIN MOST VALLEYS...WITH 35-40 ACROSS MOST HIGHER ELEVATIONS.
FOR MON NT...AS MID LEVEL WARM ADVECTION INTENSIFIES...SOME LIGHT
PRECIP IS POSSIBLE LATE. AT THIS TIME...WILL INDICATE CHC FOR SNOW
SHOWERS...BUT ENOUGH WARMING BETWEEN 925-850 MB COULD ALLOW FOR SOME
POCKETS OF RAIN OR EVEN FREEZING RAIN...SO WE WILL NEED TO MONITOR
AS EVENT NEARS.
TUE-TUE NT...NEXT WAVE AMPLIFIES ACROSS THE GREAT LAKES...WHILE AN
ACTIVE SOUTHERN SUBTROPICAL JET REMAINS ACROSS THE GULF COAST AND
SOUTHEAST STATES. ONCE AGAIN...AT LEAST A FEW MREF MEMBERS HINT AT
POTENTIAL INTERACTION BETWEEN THE TWO...WITH SOME MEMBERS DEVELOPING
A RATHER STRONG SFC LOW ALONG OR OFF THE MID ATLANTIC COAST BY LATE
TUE. WE WILL INDICATE CHC POPS FOR RAIN/SNOW SHOWERS AT THIS
TIME...BUT THERE IS AT LEAST A SLIGHT POTENTIAL FOR A MORE STEADY
PERIOD OF PRECIP. ENOUGH LOW LEVEL WARMING SHOULD FAVOR SOME RAIN
WITHIN MOST VALLEYS FOR A PERIOD TUE...BEFORE COLDER AIR MOVES
E...CHANGING ANY PRECIP BACK TO SNOW BY LATE IN THE DAY. BY TUE
NT...COLDER AIR IN THE WAKE OF THE FRONT/STORM SYSTEM SHOULD ALLOW
LAKE EFFECT SNOWBANDS TO IMPACT NW PORTIONS OF THE REGION.
HOWEVER...LOW LEVEL FLOW MAY BE MORE NW THAN CURRENT EVENT...WITH
POTENTIALLY SHORTER OVER LAKE TRAJECTORY...WHICH COULD REDUCE THE
INTENSITY SOMEWHAT.
WED-THU NT...COLD AND BLUSTERY AS UPPER TROUGH/LOW AMPLIFIES FURTHER
AS IT TRACKS E ACROSS SOUTHEAST CANADA. EXPECT LINGERING SNOW
SHOWERS AND POSSIBLE HEAVIER SNOWBANDS ACROSS NW AREAS...WITH SOME
SNOW SHOWERS POSSIBLE FURTHER S/E. TEMPS WILL REMAIN BELOW SEASONAL
LEVELS...WITH MAXES MAINLY IN THE 20S IN THE VALLEYS...AND TEENS
ACROSS HIGHER ELEVATIONS...WITH MINS MAINLY IN THE TEENS IN THE
VALLEYS...AND SINGLE DIGITS OR SLIGHTLY LOWER ACROSS HIGHER
ELEVATIONS.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH 06Z/SAT WITH MAIN
CONCERN BEING STRONG AND GUSTY WINDS. THE GUSTY WINDS WILL CONTINUE
TO BE A PROBLEM AT ALL TERMINALS THROUGH THE NEXT 24
HRS...ESPECIALLY ALBANY WHERE GUSTS COULD APPROACH 40 KTS FRIDAY
AFTERNOON. LAKE EFFECT CLOUDS ARE EXPECTED TO REMAIN AT VFR
CIGS...EXCEPT IN SNOW SHOWERS WITH MVFR CIGS AND VSBYS POSSIBLE. ANY
SNOW SHOWERS WILL BE SHORT LIVED AT THE TERMINALS...AND MAINLY
AFFECT KGFL AND KALB. OTHERWISE...VFR CONDITIONS WILL PREVAIL.
OVERNIGHT WINDS WILL DECREASE TO 10-15KT WITH GUSTS 20-25KTS.
WINDS AND WIND GUSTS WILL INCREASE AT ALL TERMINALS FRIDAY
MORNING...CONTINUING TO INCREASE THROUGH THE AFTERNOON WITH
GUSTS 30-40KTS. WINDS WILL DECREASE SLIGHTLY AFTER SUNSET.
OUTLOOK...
SAT...VFR...WINDY WITH A CHC MVFR AT GFL IN LAKE EFFECT -SHSN.
SAT NT...VFR...NO SIG WX.
SUN...VFR GOING TO MVFR CIG...CHC IFR IN -SN.
MON...VFR...NO SIG WX.
TUE...MVFR...CIG. CHC -RASN.
&&
.HYDROLOGY...
WE WILL STAY COLD ENOUGH FOR LITTLE OR NO SNOW MELT. SOME
ACCUMULATING SNOW IS LIKELY SUNDAY AND SUNDAY NIGHT...WITH SOME
LIGHT RAIN POSSIBLY MIXING IN IN THE HUDSON VALLEY AREAS.
OTHERWISE...NO HYDRO PROBLEMS ARE FORESEEN FOR THE NEXT WEEK.
SOME ICE MIGHT BEGIN TO FORM ACROSS THE NORTHERN SECTIONS OF OUR
HYDRO AREA AS TEMPERATURES DIP DOWN TO THE TEENS OR LOWER.
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...LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR NYZ032-
033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
SHORT TERM...NAS
LONG TERM...KL
AVIATION...KL
HYDROLOGY...KL/NAS
