FXUS61 KALY 111657
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1157 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/...
***AFTERNOON UPDATE ISSUED*************
AS WE APPROACH THE NOON HOUR...THE LAKE EFFECT BAND CONTINUES INTO
NORTHERN HERKIMER COUNTY. IT IS NOT QUITE AS LONG OR CONCENTRATED AS
IT ONCE HAS BEEN. VERTICAL MIXING IS PROBABLY DISRUPTING THE FLOW A
BIT...BUT SNOW IS STILL FALLING AT THE RATE OF UP TO AN INCH PER
HOUR ACROSS NORTHERN HERKIMER...LESSER AMOUNTS IN HAMILTON COUNTY.
WE THINK LATER ON TOWARD SUNSET...THE BAND SHOULD BECOME MORE
CONCENTRATED AS IT MOVES A LITTLE SOUTHWARD WITH TIME. HOWEVER...IT
LOOKS AS IF BY THE TIME IT GOES INTO SOUTHERN HERKIMER COUNTY LATER
TONIGHT IT WILL HAVE WEAKEN.
ELSEWHERE...STILL VERY LITTLE ACTIVITY IN TERMS OF SNOW
SHOWERS...VERY FEW IF ANY. WE ARE SEEING MORE INSTABILITY CELLULAR
CLOUDS BREWING. EVENTUALLY...SOME FLURRIES SHOULD COME OUT OF THE
CLOUDS IN THE HUDSON VALLEY...HARDER SNOW SHOWERS ACROSS THE HIGHER
TERRAIN...ESPECIALLY VERMONT.
PROJECTED HIGH TEMPERATURES LOOK RIGHT ON...SO NO TINKER WITH THEM.
STRONG GUSTY WINDS WILL APPROACH BUT PROBABLY NOT EXCEED WIND
ADVISORY CRITERIA...PEAKING IN THE 40-45 MPH RANGE MOHAWK VALLEY AND
HIGHER TERRAIN (INCLUDING THE GREATER CAPITAL DISTRICT).
************PREVIOUS NEAR TERM******************************
AS OF 800 AM...THE LAKE EFFECT SNOW BAND OFF ONTARIO HAS WEAKEN
CONSIDERABLY...AT LEAST FOR THE TIME BEING. DBZ VALUES WHICH
APPROACHED 40 EARLIER...HAVE DROPPED INTO THE 20S. SNOWFALL RATES
HAVE DROPPED FROM AS MUCH AS 4 INCHES PER HOUR TO UNDER 2 INCHES PER
HOUR. THE BAND HAS ALSO SHIFTED SLIGHTLY SOUTH OF ROUTE 28 IN BOTH
HERKIMER AND HAMILTON COUNTIES. THE WEAKENING APPEARS TO BE THE
RESULT OF DRIER AIR MOVING OVER THE REGION AS SEEN ON THE H20 WATER
LP. UPSTREAM...HOWEVER...THERE IS EVIDENCE OF A BIT MORE
MOISTURE...SO THE BAND MIGHT STRENGTHEN A LITTLE MORE LATER ON.
HOWEVER...IT WILL ALSO BE A LITTLE FURTHER SOUTH SO THE BRUNT OF
ACCUMULATING SNOWS WILL LIKELY BE JUST TO THE SOUTH OF OLD FORGE.
CERTAINLY NOT READY TO PULL THE LAKE EFFECT WARNING DOWN YET.
EVERYONE IN THE WARNED AREA SHOULD GET AT LEAST A FEW INCHES OF
ADDITIONAL LAKE EFFECT SNOW TODAY AND WITH THE WIND BLOWING...THERE
WILL BE ADDITIONAL WHITEOUTS AND CONTINUING DRIFTING OF THE SNOW.
MANY ROADS HAVE BEEN REPORTED IMPASSABLE EARLIER IN THIS AREA.
ELSEWHERE...MUCH QUIETER. SNOW SHOWERS OUTSIDE OF THE SNOWBAND ARE
FAR AND FEW BETWEEN...EVEN ACROSS SOUTHERN VERMONT. WE EXPECT THIS
TO CHANGE AS HEAD INTO THE AFTERNOON. WITH A SLIGHT INCREASE IN
OVERALL MOISTURE EXPECTED AS WELL AS INCREASED UPRIGHT INSTABILITY
FROM SOLAR HEATING (MEAGER THAT IT IS THIS TIME OF YEAR)...MORE
CLOUDS AND SNOW SHOWERS SHOULD FORM. WHILE THE MEAN FLOW IS NOT THE
IDEAL 320 TRAJECTORY FOR UPSLOPE SNOW ACROSS SOUTHERN VERMONT...SNOW
SHOWERS SHOULD INCREASE ACROSS THAT AREA AS WELL. AT THIS TIME...NO
ADDITIONAL HEADLINES ARE EXPECTED THERE AS ANY NEW ADVISORY SNOW
ACCUMULATIONS SHOULD VERY ISOLATED TO THE SPINE OF THE GREENS. THERE
COULD ALSO BE A COUPLE OF INCHES SNOW ACCUMULATION ACROSS THE MOHAWK
VALLEY...NEAR THE NYS THRUWAY LATER ON. ELSEWHERE...LITTLE IF ANY
ADDITIONAL SNOW WILL ACCUMULATE.
THE 12Z ALY RAOB INDICATED THAT THE PROJECTED HIGH TEMPERATURE FOR
TODAY IS RIGHT IN THE BALLPARK. SO...WHILE WE DID ISSUE A MINOR
UPDATE FOR HOURLY TRENDS/LESS CLOUDS (AT LEAST INITIALLY) AND THE
LIKE...WE KEPT THE AFTERNOON HIGHS AND OVERALL PICTURE THE
SAME.
&&
.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 /12Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH 12Z/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 THIS
AFTERNOON. LAKE EFFECT CLOUDS ARE EXPECTED TO REMAIN AT VFR
CIGS...EXCEPT IN SNOW SHOWERS WITH MVFR CIGS AND VSBYS POSSIBLE. ANY
SNOW SHOWERS SHOULD BE SHORT LIVED AT THE TERMINALS TODAY...AND
MAINLY AFFECT KGFL AND KALB. HOWEVER...WE WILL NEED TO WATCH THE
DEVELOPMENT AND ORIENTATION OF LAKE EFFECT BANDS LATER THIS
AFTERNOON...WHICH COULD IMPACT KGFL MORE ADVERSELY...THEN LATER
TONIGHT/EARLY SAT MORNING AT KALB. OTHERWISE...VFR CONDITIONS WILL
PREVAIL.
WEST WINDS WILL INCREASE TO 15-20 KT BY MID MORNING...WITH FREQUENT
GUSTS OF 20-30 KT...EXCEPT UP TO 35 KT AT KALB WHERE FUNNELING DOWN
THE MOHAWK VALLEY WILL OCCUR. GUSTINESS WILL GRADUALLY DIMINISH
TOWARD AND AFTER MIDNIGHT TONIGHT.
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
