FXUS61 KALY 110527
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1223 AM EST FRI DEC 11 2009
.SYNOPSIS...
DEEP LOW PRESSURE WILL CONTINUE MOVING NORTHEAST ACROSS EASTERN
CANADA THROUGH FRIDAY. 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 AM THIS MORNING/...
AS OF 920 PM...NO CHANGES TO HEADLINES AT THIS TIME. INTENSE LAKE
EFFECT BAND HAS ACTUALLY RETREATED A BIT FARTHER TO THE NORTH
ACROSS FAR NORTHERN HERKIMER AND HAMILTON COUNTY THIS EVENING.
HOWEVER...KTYX RADAR SHOWS BAND WIDENING AND EXTENDING FARTHER
SOUTH ACROSS THE TUG HILL PLATEAU. THIS TREND SHOULD CONTINUE INTO
NORTHERN HERKIMER AND HAMILTON COUNTIES OVERNIGHT...AS MIXED LAYER
WINDS REMAIN STRONG AROUND 35-45 KT AND MULTI-LAKE CONNECTION
PERSISTS IN CYCLONIC FLOW REGIME. BAND CURRENTLY RESIDES NORTH OF
OLD FORGE/EAGLE BAY/INLET AREAS...BUT SHOULD PROGRESS SOUTHWARD
THROUGH THE NIGHT. STILL EXPECTING SNOWFALL RATES OF AT LEAST 1-2"
PER HOUR WITHIN THE BAND.
OUTSIDE OF THE ORGANIZED LAKE EFFECT...DEEP MIXED LAYER TO 650MB
EVIDENT ON 00Z ALB SOUNDING...SO LOW-MID LEVEL INSTABILITY HAS
LED TO SOME MODERATE SNOW SHOWER ACTIVITY SCATTERED ABOUT THE AREA
WITH AID OF MOISTURE FROM LAKE ERIE PLUME ACROSS WESTERN NY. SNOW
SHOWER COVERAGE INCREASED ENOUGH TO RAISE POPS TO CHANCE AS FAR
SOUTH AND EAST AS THE CAPITAL REGION AND NORTHERN BERKSHIRES.
UPSLOPE ENHANCEMENT NOTED ON KENX RADAR ALONG SPINE OF SOUTHERN
GREEN MOUNTAINS SO WILL KEEP LIKELY POPS GOING THERE WITH MAINLY
1-3" ACCUMULATIONS.
ALSO INCREASED WIND GUST SPEEDS TO AROUND 35-45 MPH AS DEEP
MIXING OCCURS EVEN DURING THE OVERNIGHT HOURS. MAX WINDS IN MIXED
LAYER WERE AROUND 40 KT ON 00Z ALB SOUNDING SO WILL HOLD OFF ON
WIND ADVISORIES AT THIS TIME.
LOCAL WRF MODEL SUGGESTING LAKE EFFECT BAND MAY DRIFT SOUTHWARD
INTO SOUTHERN HERKIMER/NORTHERN FULTON LATE FRIDAY. STILL NOT
ENOUGH CONFIDENCE FOR A WATCH...BUT THIS WILL NEED TO BE MONITORED
SINCE BAND MAY STILL BE QUITE INTENSE TOMORROW. WILL MENTION
POTENTIAL IN HWO.
PREVIOUS NEAR TERM DISCUSSION...
AS OF 500 PM...TYX RADAR AND WEB CAMS INDICATE A FULL BLOWN LAKE
EFFECT FINALLY REACHING THE OLD FORGE AREA OF HERKIMER COUNTY. IT
HAS ALREADY BEEN SNOWING...HEAVILY AT TIMES...ACROSS THE EXTREME
NORTHERN PORTIONS OF HERKIMER COUNTY. AS THE LOW LEVEL MEAN WIND
FLOW VEERS FROM ABOUT A 260 TO A 280 VECTOR THIS BAND WILL SLOWLY
SINK SOUTHWARD INTO HERKIMER AROUND ROUTE 28 AND SHOULD EXTEND INTO
HAMILTON AND POSSIBLY EVEN WARREN COUNTY. OCCASIONALLY...THE WINDS
MIGHT AT TIMES BE STRONG ENOUGH TO DISRUPT THE BAND (AS WELL AS
SHORT WAVES PERTURBING THROUGH THE FLOW). NEVERTHELESS...TONIGHT
AS THE WIND BACKS OFF A LITTLE AND THE FLOW BECOMES BETTER ALIGNED
OFF THE LAKES WITH TEMPERATURES DROPPING LOW ENOUGH TO PRODUCE
EXTREME SLANTWISE INSTABILITY OFF LAKE ONTARIO...THE SNOW
INTENSITY WILL LIKELY INCREASE EVEN MORE.
EITHER WAY...THIS LOOKS TO BE A LONG LIVED AND PROLIFIC LAKE SNOW
EVENT FOR PORTIONS OF OUR SOUTHERN ADIRONDACKS. WARNINGS REMAIN
POSTED FOR BOTH HAMILTON AND NORTHERN HERKIMER COUNTIES UNTIL AT
LEAST 12Z SATURDAY. WE STILL EXPECT 1 TO LOCALLY THREE FEET OF SNOW
IN THIS AREA WHEN THE LAKE EFFECT WINDS DOWN ON SATURDAY. PLEASE
REFER TO ALL OF OUR WINTER WEATHER MESSAGE (WSW) AND NOWCASTS FOR
UPDATES ON THIS EVENT.
SNOW SHOWERS HAVE BEEN AFFECTING OTHER AREAS OF THE MOHAWK
VALLEY...INTO SOUTHERN VERMONT. THESE WERE MORE CELLULAR LOOKING AND
IN ADDITION TO LAKE MOISTURE ARE PARTIALLY THE RESULT OF COLD AIR
ADVECTION PRODUCING UPRIGHT (AS OPPOSED TO SLANTWISE) INSTABILITY.
THE WIND IS TURNING MORE WESTERLY (AS OPPOSED TO SOUTHWESTERLY) SO
SOME UPSLOPE IS TAKING PLACE ALONG THE SPINE OF THE SOUTHERN GREENS.
AS THE WIND EVENTUALLY TURNS NW...THE UPSLOPE THERE SHOULD INTENSIFY
A LITTLE.
RIGHT NOW...THIS SCENARIO LOOKS TO PRODUCE LOCALIZED ACCUMULATIONS
OF SNOW BELOW ADVISORY THRESHOLD. HOWEVER WE WILL CONTINUE TO
MONITOR THE SITUATION.
ALSO...THE WINDS WILL KICK UP A BIT AS THE GRADIENT TIGHTENS BETWEEN
DEPARTING LOW PRESSURE INTO CANADA...AND HIGH PRESSURE BUILDING IN
TO OUR SOUTH. WITH THE EXCEPTION OF BUFFALO...THERE WERE NO PENNANTS
(50KT WINDS) UPSTREAM OF OUR REGION. THE 50KT JET OVER BUFFALO WILL
LIKELY WEAKEN A LITTLE AS IT HEADS EASTWARD. WE ARE FORECASTING WIND
GUSTS TO REMAIN JUST BELOW WIND ADVISORY BUT IT WILL BE VERY CLOSE.
FOR NOW...NO WIND HEADLINES WILL BE ISSUED BUT WE WILL MENTION OUR
CONCERNS IN THE HAZARDOUS WEATHER OUTLOOK.
AS ARCTIC AIR IS SLOWLY DRIVEN INTO THE REGION...TEMPERATURES SHOULD
DROP DOWN TO AROUND 20 FOR OVERNIGHT LOWS LOCALLY...TEENS OUTLYING
AREAS...EXCEPT SINGLE DIGITS ACROSS THE HIGHEST TERRAIN. WIND CHILL
READINGS WILL DIP BELOW ZERO IN THE MOUNTAINS...SINGLE DIGITS
ELSEWHERE. COLD...BUT NOT LOW ENOUGH FOR ADVISORIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
THE SAME ISSUES...LAKE EFFECT/WIND AND COLD WILL BE THE THEME FRIDAY
INTO FRIDAY NIGHT. H850 TEMPERATURES ARE FORECAST TO DIP BETWEEN -18
TO -15C ACROSS OUR REGION. IRONICALLY...THE COLDEST VALUES ARE FOUND
IN OUR SOUTHERN AREAS! H850 TEMPERATURES STAY CLOSE TO THESE VALUES
INTO SATURDAY.
THE TREMENDOUS LAKE EFFECT IMPACTING NORTHERN HERKIMER AND HAMILTON
COUNTIES SHOULD CONTINUE INTO AT LEAST SATURDAY MORNING. SOME
UPSLOPE SNOW SHOWERS WILL PERSIST ACROSS THE GREENS. THE REST OF THE
AREA WILL SEE ISOLATED TO SCATTERED SNOW SHOWERS WILL LITTLE OR NO
SNOW ACCUMULATIONS OUTSIDE OF A A COUPLE INCHES POSSIBLE IN THE
MOHAWK VALLEY.
TEMPERATURES ON FRIDAY WILL BE QUITE A BIT COLDER THAN TODAY
(THURSDAY). WE EXPECT READINGS TO TOP OUT ONLY NEAR 30 IN THE MID
HUDSON VALLEY/LITCHFIELD COUNTY...WITH 20S MOST OTHER
PLACES...EXCEPT TEENS ACROSS THE MOUNTAINS. THE WIND WILL MAKE THESE
VALUES FEEL COLDER. COLD FRIDAY NIGHT WITH LOWS TUMBLING INTO THE
TEENS AND SINGLE DIGITS. ENOUGH OF A BREEZE AND LAKE EFFECT CLOUDS
SHOULD KEEP MOST PLACES ABOVE ZERO...EXCEPT FOR PERHAPS A FEW SNOW
COVERED MOUNTAIN VALLEYS.
SATURDAY WILL SEE SIMILAR CONDITIONS TO FRIDAY EXCEPT THE LAKE
EFFECT BAND OFF LAKE ONTARIO MIGHT BEGIN SLIPPING TOWARD THE NEW
YORK STATE THRUWAY. IF THIS HAPPENS...THE HEAVIEST SNOW WOULD FALL
JUST SOUTH OF ROUTE 28 AND A FEW OF THESE SHOWERS COULD MAKE IT INTO
THE CAPITAL REGION. UPSLOPE SCATTERED SNOW SHOWERS WILL CONTINUE
ACROSS VERMONT AND POSSIBLY EVEN INTO THE BERKSHIRES. HIGH
TEMPERATURES WILL BE SIMILAR TO FRIDAY HIGHS...GENERALLY IN THE
20S...TO AROUND 30 IN OUR SOUTHERN ZONES.
EVENTUALLY...HIGH PRESSURE WILL SETTLE OVER OUR REGION BY SATURDAY
NIGHT. THIS MIGHT BE OUR COLDEST NIGHT. BY THIS TIME HOWEVER...THERE
ARE INDICATIONS THAT HIGH CLOUDS MIGHT ALREADY BE MOVING IN AHEAD OF
THE NEXT SYSTEM. FOR NOW...DID FORECAST TEMPS MUCH COLDER THAN
FRIDAY NIGHT...BUT IF IT WERE TO CLEAR...THEY WOULD TURN OUT A LOT
COLDER AS THE WIND WILL BE LIGHT. BY THIS TIME...ALL LAKE EFFECT
SNOW...SHOULD BE OVER.
ON SUNDAY...AS HIGH PRESSURE RETREATS OFFSHORE IT WILL PRODUCE WARM
AIR ADVECTION CLOUDS. THE GFS HAS BEEN INDICATING FOR QUITE A FEW
ROUNDS NOW...A WEAK SOUTHERN STREAM SYSTEM TRENDING A LITTLE FURTHER
NORTH WITH EACH RUN. THE TREND IS NO LONGER FURTHER NORTH...BUT A
WEAK LOW TRACKS OFF THE CAROLINA COAST. THE COMBINATION OF A RETURN
SOUTHERLY FLOW...THE WARM AIR ADVECTION...AND LOW LEVEL CONVERGENCE
FROM AN INVERTED TROUGH EXTENDING NORTHWARD FROM THE LOW
PRESSURE...LOOK MORE AND MORE LIKELY TO PRODUCE A PERIOD OF SNOW
ACROSS MUCH OF THE AREA...ESPECIALLY SOUTH OF ALBANY. NOW...THE
EUROPEAN/NAM AND EVEN CANADIAN GEM SUPPORT SOME OF PRECIPITATION
DEVELOPING ACROSS THE AREA...WITH THE EUROPEAN THE LIGHTEST THUS
FAR. IT DOES NOT LOOK LIKE A BIG STORM...BUT COULD POTENTIALLY
PRODUCE UP TO ADVISORY LEVELS ESPECIALLY SOUTH. HOWEVER...THE COLUMN
MIGHT ACTUALLY WARM UP ENOUGH FOR A LITTLE RAIN TO MIX IN SOUTH. FOR
NOW...JUST WENT WITH A GENERIC 50 PERCENT OF SNOW EVERYWHERE AS THE
POSSIBLE EVENT IS STILL DAYS AWAY. WHATEVER STORM WE DO GET IS
EXPECTED TO SLOWLY MOVE OFFSHORE SUNDAY NIGHT WITH A BIT MORE
RESIDUAL SNOW.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
CONDITIONS WILL DRY FOR MONDAY WITH A WEAK RIDGE OF HIGH PRESSURE
BUILDING IN BEHIND SUNDAY/S POSSIBLE STORM. SOME LINGERING SHOWERS
ARE POSSIBLE EARLY MONDAY. WEAK HIGH PRESSURE WILL NOT LAST LONG AS
RATHER ZONAL FLOW OVER THE US WILL ALLOW THE NEXT SYSTEM TO QUICKLY
MOVE IN FROM THE WESTERN GREAT LAKES BY MONDAY NIGHT INTO TUESDAY.
PRECIPITATION FROM THIS STORM WILL START OFF AS SNOW...TRANSITIONING
TO RAIN IN THE AFTERNOON...EXCEPT FOR ELEVATIONS ABOVE 1500 FEET
WHICH WILL SEE A RAIN/SNOW MIX ON TUESDAY. TUESDAY NIGHT
TEMPERATURES WILL BE COLD ENOUGH TO TRANSITION THE RAIN BACK TO SNOW
ACROSS THE FA...WITH SNOW TAPERING OFF ON WEDNESDAY MORNING. BEHIND
THIS SYSTEM...NORTHWESTERLY FLOW WILL PREVAIL...KEEPING A CHC OF
SNOW OVER THE ADIRONDACKS FROM LAKE EFFECT SNOW SHOWERS THROUGH LATE
WEDNESDAY/EARLY THURSDAY. OTHERWISE...SFC HIGH PRESSURE WILL RETURN
LATE THURSDAY.
THE PERIOD WILL START WITH ABOVE NORMAL TEMPERATURES FOR MONDAY AND
TUESDAY. AFTER THE NEXT SYSTEM ON LATE MONDAY INTO TUESDAY...COLDER
AIR WILL FILTER IN WITH TEMPERATURES DECREASING TO 5-10 DEGREES
BELOW NORMAL THROUGH THE REST OF THE PERIOD.
&&
.AVIATION /06Z 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.
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...HWJIV
NEAR TERM...HWJIV/JPV
SHORT TERM...RCK
LONG TERM...KGS
AVIATION...KL/KGS/ELH
HYDROLOGY...HWJIV
