FXUS61 KALY 061551
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1051 AM EST SUN DEC 6 2009
.SYNOPSIS...
A COLD HIGH PRESSURE RIDGE WILL BUILD INTO OUR REGION TODAY IN THE
WAKE OF THE SEASONS FIRST SNOWSTORM. IT WILL PUSH COLD AIR OVER
THE GREAT LAKES AND RESULT IN LAKE EFFECT SNOW SHOWERS AND
FLURRIES IN AREAS NORTH AND WEST OF ALBANY THOUGH MONDAY. WEAK LOW
PRESSURE WILL MOVE THROUGH THE GREAT LAKES REGION MONDAY AND
ENHANCE THE LIGHT SNOW AND CLOUDS. HIGH PRESSURE WILL BRIEFLY
CREST OVER THE REGION TUESDAY. A MORE SIGNIFICANT STORM WILL APPROACH
FROM THE SOUTHWEST MIDWEEK BRINGING WIDESPREAD PRECIPITATION TO
THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
A FINAL PUBLIC INFORMATION STATEMENT HAS BEEN ISSUED WITH SNOWFALL
REPORTS FROM ACROSS THE FORECAST AREA.
MINOR UPDATE TO GRIDS FOR TODAY. HAVE LAKE EFFECT SNOW SHOWERS
EXTENDING INTO THE WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND
HELDERBERGS. ACTIVITY WILL SHIFT NORTHWARD INTO THE WETSERN
ADIRONDACKS TODAY AS THE LOW LEVEL FLOW BECOMES MORE WESTERLY.
PREVIOUS DISCUSSION ISSUED AT 330 AM...THE SEASONS FIRST
WIDESPREAD SNOW EVENT IS OVER AND THE STORM IS EXITING OUT INTO
THE NORTH ATLC. SFC HIGH PRESSURE RIDGE IS BUILDING FM OHIO TWRD
SAINT LAWRENCE VLY. BUT CAA LEAVES 21C DIFFERENTIAL FLOWING ACROSS
LK ONTARIO. LAST LOBE OF 500HPA VORTICITY ALSO PASSING OVER
REGION. RESULT WAS FAIRLY LARGE AREA OF --SHSN OVER MUCH OF W PTN
OF FCA...WHICH HAS BEEN SHRINKING RAPIDLY. CURRENTLY ANTICYCLONIC
SFC FLOW AND 6KFT INVERSION IS KEEPING LID ON LAKE RESPONSE BUT
THE INTERPLAY BETWEEN THE SYSTEMS AND AN APPROACHING 80-90KT
500HPA JET WILL RESULT IN A RATHER VARIED WEATHER SCENARIO OVER
FCA INTO MONDAY.
THINNING OF CLOUDS BETWEEN THE DEPARTING SYSTEMS AND THE LAKES. FOR
A TIME THE SUBSIDENCE BEHIND THE DEPARTING SFC STORM WILL RESULT
IN CLEARING IN MANY AREAS TWRD DAYBREAK. WITH LESS THAN OPTIMAL
DYNAMICS FROM LAKE ONLY SCT -SHSN AND FLURRIES WILL RESULT UNTIL
THE CONFIGURATION IMPROVES DURING TODAY.
DURING AFTN NEXT 500HPA JET MAX PUSHES ACROSS RGN LEAVING FCA IN
LEFT EXIT REGION. THIS JET THEN LIFTS N TNGT INTO MONDAY AND FCA
IS IN RIGHT ENTRANCE RGN. THE INVERSION RISES TWRD 10KFT...AND
FROM MIDDAY ON THE ENVIRONMENT FOR LK RESPONSE IMPROVES AND THE
LOCAL WRF AND NAM SUGGEST AND 270-280 DEGREE VECTOR MOSTLY SINGLE
BAND SETTING UP INTO TUG HILL AND W ADIRONDACKS. WRF PROBABLY
OVERDOING THE QPF AND THE NAM UNDER- DOING IT. WHILE CONDITIONS
ARE NOT "IDEAL" TODAY AND TONIGHT THEY ARE GOOD ENOUGH TO SUPPORT
THIS BAND FOR A FEW INCHES IN HERKIMER AND HAMILTON COUNTIES AND
-SHSN FURTHER EAST...WITH INCREASED CLOUDS FM MHWK VLY NORTH.
TODAY WILL START MOSTLY SUNNY FM HUD VLY EAST...BUT WILL BCM PS N
OF ALB.
OVERNIGHT WEAK BOUNDARY SETS UP ACROSS N TIER OF NYS AND NEW ENG...AND
WEAK LOW PRESSURE FORMS OVER GRTLKS. THIS BOUNDARY INTERACTING
WITH LK MOISTURE PLUMES WILL CAUSE CLOUDS TO INCREASE OVER ALL N
AREAS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
MONDAY SFC FRONTOGENESIS IS SETTING UP FM NVT TO TOL AND WK SFC
LOWS ARE RIPPLING ALONG THIS FRONT. YET ANOTHER 500HPA JET MAX IS
EJECTING ACROSS THE REGION. THIS WILL ALL BE INTERACTING WITH LAKE
MOISTURE PLUMES AND STILL 17C DIFFERENTIAL AND THE RESULT WILL BE
ALOT OF CLOUDS AND SCT -SHSN OVER ALL AREAS EXCEPT S TIER...WHERE
PARTLY SUNNY CONDS WILL PERSIST.
IN NORTHERN MOST SECTIONS OF REGION EXPANSIVE SINGLE LAKE ONTARIO
BAND AND FRONTAL BOUNDARY WILL INTERACT...INCREASING THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOWS MONDAY. EVEN THE NAM PICKS
UP THIS FEATURE WELL. BULK OF THIS WILL BE NORTH OF FCA...BUT MAY
IMPACT THE NORTHERN MOST REACHES ON HAMILTON AND HERKIMER COUNTIES.
FINALLY TUESDAY THE UPPER DYNAMICS DEPART BRIEFLY...SFC HIGH
RIDGES OVER RGN AND MOST OF AREA WILL BE DRY WITH ONLY ISOLD -SHSN
NORTH BEFORE NEXT SYSTEM APPROACHES FOR MID WEEK. MODELS SUGGEST
PS CONDS..BUT CONCERN REMAINS ABOUT A "DIRTY RIDGE" AS ALL THIS
LOW LEVEL MOISTURE GETS TRAPPED UNDER AN INVERSION.
THE NAM/GFS/GEM AND WRF ARE PRETTY MUCH IN AGREEMENT THROUGH THE
PERIOD. ONLY VARIATIONS ARE IN MAGNITUDE OF LAKE RESPONSE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE GFS...ECM...AND GEM ARE ALL IN REASONABLE AGREEMENT WITH
EACH OTHER THROUGH THURSDAY.
ON TUESDAY NIGHT...HIGH PRESSURE CENTERED OVER NORTHERN NEW YORK
STATE SHIFTS EAST INTO THE MARITIMES...MAKING WAY FOR A RATHER
INTENSE SYSTEM WHICH MOVES OUT OF THE SOUTHERN ROCKIES INTO THE
PLAINS BY TUESDAY EVENING...AND INTO THE LOWER OHIO VALLEY BY
WEDNESDAY MORNING...AS A SHORT WAVE ROTATES EAST FROM THE
ROCKIES TO THE WESTERN GREAT LAKES. A WEAK LOW FORMS ALONG THE
WARM FRONTAL BOUNDARY NEAR CAPE HATTERAS WEDNESDAY MORNING BUT
THE PRIMARY LOW CONTINUES TO INTENSIFY AS IT MOVES NORTHEAST
INTO SOUTHERN CANADA JUST WEST OF LAKE ONTARIO...WHILE THE
SECONDARY LOW BEGINS TO CONVERGE WITH THE PRIMARY. THE SECONDARY
LOW BEGINS TO INTENSIFY RAPIDLY ON THURSDAY AND TAKES OVER FROM
THE PRIMARY LOW AS IT LIFTS NORTH THROUGH THE MARITIMES. BY
12Z FRIDAY IT WILL BE JUST NORTH OF THE GULF OF ST LAWRENCE.
THIS LOW WILL CONTINUE TO SLOWLY MOVE NORTHEASTWARD AWAY FROM
THE REGION AS A SURFACE HIGH MOVES ACROSS THE EASTERN STATES
THURSDAY NIGHT AND FRIDAY...FOLLOWED BY A COLD FRONT PASSING
THROUGH THE REGION SATURDAY MORNING.
SKIES CLOUD UP ACROSS THE REGION TUESDAY NIGHT...WITH SNOW
SPREADING INTO THE REGION BY AROUND DAYBREAK WEDNESDAY.
TEMPERATURES EARLY WEDNESDAY WILL MOSTLY BE IN THE 20S.
AS WARMER AIR BEGINS TO WORK ITS WAY INTO THE REGION...IT WILL
CAUSE THE SNOW TO MIX WITH...AND IN SOME AREAS...CHANGE OVER
TO...RAIN...WITH HIGHS IN THE 30S AND LOW 40S. FOR PRECIP
AMOUNTS...WE ARE LOOKING AT TOTAL LIQUID EQUIVALENTS BETWEEN
0.8 AND 1.3 INCHES. SNOWFALL WILL BE A MUCH TRICKIER ISSUE...
WITH THE MIX OF RAIN WITH SNOW IT NOW APPEARS THAT HEAVY
SNOWFALL AMOUNTS OF 8 INCHES OR MORE WILL BE CONFINED TO
THE ADIRONDACKS...WITH LESSER AMOUNTS SOUTH AND EAST WHERE
MORE OF THE MOISTURE MAY COME AS RAIN...OR A MIX OF THE TWO.
BY LATER WEDNESDAY SOMEWHAT DRIER AIR WILL WORK ITS WAY INTO THE
REGION FROM THE SOUTHWEST. IT WILL COOL OFF SOME WEDNESDAY NIGHT
WITH LOWS IN THE 20S AND LOW 30S...AND WARM ONLY TO THE UPPER 20S
AND ID 30S THURSDAY AS THE WINDS SHIFT AROUND TO A MORE WESTERLY
DIRECTION AND BRING A FLOW OF COLD AIR OUT OF CENTRAL CANADA INTO
THE REGION. WE MAY EXPERIENCE LONG LAKE AXIS PARALLEL WINDS...
WHICH WOULD BE LIKELY TO FORM A BAND OF LAKE EFFECT SNOW EXTENDING
INTO HERKIMER...HAMILTON...FULTON...AND POSSIBLY MONTGOMERY
COUNTIES THURSDAY NIGHT INTO FRIDAY. WE MAY ALSO BE DEALING
WITH GUSTY EASTERLY WINDS ON WEDNESDAY...AND GUSTY WESTERLY
WINDS ON THURSDAY AS A STRONG PRESSURE GRADIENT DEVELOPS BETWEEN
THE LOW IN CANADA AND HIGH PRESSURE OVER THE LOWER MISSISSIPPI
VALLEY...WHICH COULD HAMPER SNOW REMOVAL OPERATIONS...ESPECIALLY
IN THE ADIRONDACKS WHERE LAKE EFFECT SNOWFALL IS LIKELY TO
PERSIST. IT WILL GET QUITE COLD THURSDAY NIGHT...LOWS FROM THE
MID TEENS TO THE MID 20S...AND BE QUITE CHILLY ON FRIDAY WITH
HIGHS ONLY FROM THE MID 20S TO THE UPPER 30S. ANOTHER CHILLY
NIGHT ON STORE FRIDAY NIGHT...HIGH SINGLES TO NEAR 20...AND
A RATHER CLOUDY...RAW...AND CHILLY DAY ON SATURDAY WITH HIGHS
FROM THE UPPER 20S TO THE MID 30S...LOTS OF CLOUDS...BLUSTERY
NORTHWEST WINDS 10 TO 15 MPH...AND WIDESPREAD FLURRIES AND SNOW
SHOWERS.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
VFR FLIGHT CONDITIONS EXPECTED AT TAF SITES THROUGH 12Z/MONDAY.
HOWEVER...MVFR CONDITIONS ARE EXPECTED WITH THE LAKE EFFECT SNOW
SHOWERS TO THE WEST OF THE CAPITAL DISTRICT. WESTERLY WINDS TODAY
WITH GUSTS IN THE TEENS THIS AFTERNOON EXPECTED AT KALB. WINDS
WILL BECOME LIGHT THIS EVENING.
OUTLOOK...
MON...VFR/MVFR...CHC -SHSN NORTH OF CAPITAL DISTRICT.
TUE...VFR...NO SIG WX.
WED...MVFR/IFR. A WINTRY MIX OF PRECIP LIKELY.
THUR...VFR/MVFR...CHC -SHSN/-SHRA. WINDY.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS EXPECTED THROUGH EARLY WEDNESDAY AS ANY
PRECIPITATION UP TO THAT TIME WILL COME IN THE FORM OF SNOW
AND THUS HAVE NO DIRECT IMPACT ON THE RIVERS. HOWEVER ON
WEDNESDAY SNOW IS EXPECTED TO CHANGE TO RAIN ACROSS THE
SOUTHERN AND EASTERN PARTS OF OUR FORECAST AREA...WHICH
WILL THEN MELT AT LEAST SOME OF THE SNOW. IT APPEARS THE
RIVERS MOST LIKELY TO BE AFFECTED WILL BE THE HOUSATONIC
AND ITS TRIBUTARIES IN CONNECTICUT ALONG WITH THE RONDOUT...
WAPPINGERS...KINDERHOOK...AND TENMILE IN EASTERN NEW YORK.
FARTHER NORTH...TEMPERATURES ARE EXPECTED TO REMAIN COOL
ENOUGH AND ENOUGH SNOW ACCUMULATE BEFORE THE CHANGE TO
RAIN TO JUST SOAK IT UP RATHER THAN MELT OFF THE SNOW.
THUS ONLY A LIMITED RESPONSE IS EXPECTED ON THE ESOPUS...
SCHOHARIE...HOOSIC..BATTENKILL...AND THE MOHAWK RIVER.
THERE WILL BE VERY LITTLE...IF ANY...IMPACT ON RIVERS
FARTHER NORTH SUCH AS THE EAST AND WEST CANADA...THE
SACANDAGA...THE HUDSON ABOVE GLENS FALLS...THE SACANDAGA
RIVER...OR RIVERS IN SOUTHERN VERMONT.
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.E /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...IAA/SNYDER
SHORT TERM...SNYDER
LONG TERM...RCK
AVIATION...IAA/RCK
HYDROLOGY...RCK
