FXUS61 KALY 301831
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
100 PM EST MON NOV 30 2009
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK ACROSS NORTHERN NEW ENGLAND TODAY.
A COLD FRONT TRAILING FROM THIS LOW WILL MOVE ACROSS THE REGION THIS
MORNING...PRECEDED AND ACCOMPANIED BY RAIN SHOWERS. MUCH COLDER AIR
WILL FOLLOW IN THE WAKE OF THIS FRONT FOR TONIGHT THROUGH WEDNESDAY.
A MORE POTENT STORM SYSTEM SHOULD BRING A SOAKING RAIN TO THE REGION
WEDNESDAY NIGHT INTO THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1100 AM...STILL LOOKING AT A BATCH OF SHOWERS...MAINLY SOUTH
OF THE CAPITAL DISTRICT...WITH DRIER AIR SQUELCHING SHOWERS NORTH
AND WEST OF ALBANY. SOME OF THESE LEFTOVER SHOWERS HAVE TURNED TO
SNOW SHOWERS AS SURFACE TEMPERATURES HAVE DROPPED TO NEAR FREEZING.
SLOWLY...THE DRIER AIR WILL OVERSPREAD THE REMAINDER OF THE REGION
AS A SHORT WAVE PULLS AWAY...PULLING THE COLD FRONT FURTHER SOUTH.
THE ONLY EXCEPTION IS A FEW LAKE ENHANCED SHOWERS MIGHT DEVELOP
ACROSS PORTIONS OF THE MOHAWK VALLEY AND ADIRONDACKS LATE IN THE
AFTERNOON AS THE SFC-H700 BECOMES MORE FAVORABLE FOR MOISTURE OFF OF
LAKE ONTARIO. THESE SHOWERS OF MOSTLY SNOW SHOULD HAVE LITTLE
IMPACT.
TEMPERATURES WILL LIKELY NOT RISE MUCH AT ALL FOR THE REMAINDER OF
THE AFTERNOON...AND IN SOME CASES...MIGHT EVEN FALL A LITTLE.
CLOUDS WILL SLOWLY DIMINISH AND A FEW BREAKS OF SUNSHINE ARE A GOOD
BET...AT LEAST IN THE HUDSON VALLEY...LATER DURING THE AFTERNOON.
************PREVIOUS NEAR TERM FORECAST****************
AS OF 930 AM...THE COLD FRONT HAS MOVED THROUGH THE CAPITAL
DISTRICT...AND IS NEAR A KAQW/KMSV LINE. THIS FRONT IS SLOWING DOWN
AS SHORT WAVE MOVES ALONG IT. THIS SHOULD ALLOW FOR A SLOW INCREASE
IN SHOWER ACTIVITY IN OUR SOUTHERN ZONES.
HAVE UPDATED THE FORECAST TO DEPICT CURRENT TEMPERATURE
TRENDS...WHICH WARMER SOUTH/SLIGHTER COOLER NORTH THAN PREVIOUSLY
FORECASTED. TOUCHED UP POPS AND LOWERED QPF FOR THE MORNING HOURS.
LEFT THE AFTERNOON POPS AND QPF ALONE FOR NOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
TONIGHT...MAIN AREA OF PRECIPITATION SHOULD SHIFT S/E OF REGION
SHORTLY AFTER SUNSET. THEREAFTER...A PERIOD OF CLEARING IS
EXPECTED AS A WEAK SHORTWAVE RIDGE BUILDS EASTWARD ACROSS THE
REGION. HOWEVER...SOME UPSLOPE CLOUDS...AND PERHAPS FLURRIES ARE
POSSIBLE ACROSS HIGHER ELEVATIONS OF SOUTHERN VT/WESTERN MA THIS
EVENING. THEN...AFTER MIDNIGHT...WITH THE APPROACH OF A SHORTWAVE
FROM THE W...SNOW SHOWERS/FLURRIES ARE EXPECTED TO DEVELOP ACROSS
THE WESTERN ADIRONDACKS...AND PERHAPS THE WESTERN MOHAWK VALLEY
AND SCHOHARIE VALLEY TOWARD DAYBREAK. ELSEWHERE...AFTER A PERIOD
OF MOSTLY CLEAR SKIES...CLOUDS SHOULD INCREASE FROM W TO E TOWARD
DAYBREAK GIVEN THE APPROACH OF THE SHORTWAVE. GIVEN THE
EXPECTATION FOR A PERIOD OF CLEARING...AND LIGHT WINDS ASSOCIATED
WITH SHORTWAVE RIDGE PASSING THROUGH...WE HAVE SIDED WITH THE
COLDER MET MOS NUMBERS...WHICH ARE GENERALLY IN THE MID/UPPER
20S...EXCEPT UPPER TEENS TO LOWER 20S ACROSS NORTHERN AREAS.
TUE...AS A SHORTWAVE AND ASSOCIATED MID LEVEL COLD POOL CROSS THE
REGION...WE EXPECT SKIES TO BECOME MOSTLY CLOUDY...ALONG WITH
SCATTERED TO NUMEROUS SHOWERS OF RAIN AND SNOW ACROSS THE REGION. IN
FACT...SEVERAL INDICATORS HINT AT POSSIBLE WINDEX ACTIVITY...MAINLY
THE APPROACH OF THE TROUGH...COMBINED WITH RH GREATER THAN 50
PERCENT IN THE LOW/MID LEVELS...INCREASING LI/S...AND STEEPENING LOW
LEVEL LAPSE RATES. THIS SHOULD SUPPORT NUMEROUS SNOW SHOWERS ACROSS
THE HIGHER ELEVATIONS OF THE ADIRONDACKS...AND THE WEST FACING
SLOPES OF THE SOUTHERN GREEN MOUNTAINS...WHERE 1-3 INCHES OF SNOW
COULD OCCUR. ELSEWHERE...A SLIGHTLY WARMER BOUNDARY LAYER MAY ALLOW
FOR RAIN AND SNOW SHOWERS...AND WITH A DOWNSLOPING W FLOW...WILL
SCALE BACK POPS INTO THE SLIGHT CHC RANGE. AS FOR MAX TEMPS...HAVE
SIDED CLOSER TO THE COOLER MET MOS...WITH MAINLY LOWER 40S WITHIN
THE VALLEYS...AND 30S ACROSS MOST HIGHER ELEVATIONS.
TUE NT...SCATTERED SNOW SHOWERS WILL REMAIN POSSIBLE ACROSS
FAVORABLE UPSLOPE AREAS OF SOUTHERN VT/WESTERN MA...AND WITHIN THE
SOUTHERN ADIRONDACKS EARLY BEFORE GRADUALLY TAPERING OFF LATE.
HOWEVER...LOW CLOUDS COULD LINGER THROUGHOUT THE NIGHT ACROSS
CENTRAL AND NORTHERN AREAS GIVEN RAPIDLY LOWERING INVERSION LEVELS
AND RESIDUAL LAKE MOISTURE BECOMING TRAPPED UNDERNEATH. WILL
THEREFORE INDICATE MINS A BIT WARMER ACROSS CENTRAL AND NORTHERN
AREAS THAN MON NT/TUE AM...SLIGHTLY CLOSER TO THE MAV MOS IN SOME
AREAS...WITH MINS MAINLY RANGING FROM THE MID 20S ACROSS THE
DACKS...TO THE UPPER 20S TO LOWER 30S ELSEWHERE.
WED...HIGH PRESSURE RIDGE WILL MOVE E ACROSS THE REGION...AND OFF TO
OUR E BY LATE AFTERNOON. HOWEVER...MID LEVEL WARM ADVECTION WILL
INTENSIFY...IN RESPONSE TO DEEPENING TROUGH TO OUR W. THIS SHOULD
ALLOW AT LEAST HIGH/MID LEVEL CLOUDS TO INCREASE BY AFTERNOON...WITH
ONLY A BRIEF PERIOD OF SUNSHINE EXPECTED FROM MID MORNING INTO EARLY
AFTERNOON. THUS...HAVE INDICATED COOLER MAXES...IN LINE WITH THE MET
MOS...WITH FORECAST MAXES GENERALLY IN THE MID 40S ACROSS
VALLEYS...AND UPPER 30S/LOWER 40S FOR HIGHER TERRAIN. SOME LIGHT
RAIN COULD DEVELOP TOWARD EVENING ACROSS SOUTHERN AREAS...SHOULD THE
AFOREMENTIONED WARM ADVECTION BECOME EVEN STRONGER THAN CURRENTLY
EXPECTED...AND THUS WE HAVE INDICATED SLIGHT CHC POPS FOR THESE
REGIONS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FOR WEDNESDAY NIGHT INTO THURSDAY...THE DETERMINISTIC LONG RANGE
GUIDANCE /ECMWF...GFS...CANADIAN GGEM/ ALL INDICATE A RATHER POTENT
STORM SYSTEM LIFTING NORTHEAST FROM THE TENNESSEE VALLEY WEDNESDAY
EVENING INTO WESTERN OR CENTRAL NEW YORK THURSDAY MORNING AND INTO
THE CANADIAN MARITIMES THURSDAY EVENING. WHILE THE EXACT TRACK OF
THE SYSTEM REMAINS UNCERTAIN...IT DOES APPEAR THAT SYSTEM WILL TRACK
TO THE WEST OF FA ALLOWING PLENTY OF WARM AIR TO RUSH IN WEDNESDAY
NIGHT INTO THURSDAY MORNING SUCH THAT MOST IF NOT ALL OF THE PCPN
WILL BE IN THE FORM OF RAIN WHICH IS WHAT WE HAVE IN THE GRIDS FOR
WEDNESDAY NIGHT INTO THURSDAY. SOME OF THIS PCPN COULD BE
SIGNIFICANT AS FLOW FROM GULF APPEARS TO BE OPEN WITH ALL MODELS
INDICATING THAT H5 CLOSED LOW OPENS AS IT LIFTS FROM MID MISSISSIPPI
VALLEY WEDNESDAY NIGHT INTO THE EASTERN GREAT LAKES AND WEAKENS AS
AS H5 LOW OVER WESTERN GREAT LAKES BECOMES THE DOMINANT FEATURE. AND
THE ENSEMBLES CONTINUE TO INDICATE A STORM SYSTEM INTERACTING WITH
THE SUBTROPICAL JET STREAM WILL APPROACH FROM THE TN AND OH VALLEYS
WED NIGHT. THE AMOUNT OF GULF MOISTURE THAT IS TAPPED AND THE EXACT
TRACK OF THE INTENSIFYING LOW PRESSURE SYSTEM IS STILL UNCERTAIN AND
THIS COUPLED WITH DAY 4 FOR MAIN ACTIVITY PRECLUDES MENTION IN THE
HWO AT THIS TIME...BUT IT DOES NEED TO BE MONITORED CLOSELY. MREF
PLUME FOR KALB HAS ALL RAIN WITH GENERALLY BTWN 1 AND 2 INCHES OF
QPF WITH A MEAN OF AROUND AN INCH AND A QUARTER. FOR NOW HAVE LIKELY
POPS WEDNESDAY NIGHT INTO THURSDAY MORNING AND THEN TAPER TO CHANCE
POPS THURSDAY AFTERNOON AS DRY SLOT EXPECTED TO MOVE ACROSS FA WITH
LOW LIFTING INTO CANADIAN MARITIMES. HAVE LOWS WEDNESDAY NIGHT IN
THE 30S WITH HIGHS ON THURSDAY IN THE UPPER 30S NORTHWEST TO MID 50S
SOUTHEAST. DID NOT USE A NON DIURNAL TREND THIS FAR OUT ALTHOUGH IT
IS POSSIBLE THAT TEMPS MAY DROP THURSDAY AFTERNOON.
THU NIGHT INTO SAT...IN THE WAKE OF THE SURFACE LOW STRONG COLD AIR
ADVECTION TAKES PLACE WITH FAIRLY STRONG CYCLONIC FLOW AND AS A
RESULT SOME LAKE EFFECT SNOWS ARE POSSIBLE ESPECIALLY ACROSS THE
WESTERN ADIRONDACKS AND NORTHERN PORTIONS OF THE MOHAWK VALLEY. THIS
LOOKS TO BE A FAIRLY PROLONGED LAKE EFFECT EVENT AS LAKE ONTARIO
TEMPS WILL LIKELY STILL BE IN THE MID 40S AND H8 TEMPS LOOK TO DROP
TO AROUND -10 C LATE THURSDAY NIGHT AND REMAIN AROUND -10 C ON
FRIDAY AND DROP -12 OR -13 C ON FRIDAY NIGHT BEFORE RISING SLIGHTLY
ON SATURDAY.
SATURDAY NIGHT INTO SUNDAY...THE LOW LEVEL FLOW BECOMES ANTICYCLONIC
WHICH SHOULD BRING AN ABRUPT END TO THE LAKE EFFECT ACTIVITY AND
ALLOW TEMPS TO MODERATE AS RIDGING BRIEFLY BUILDS INTO THE REGION
BEFORE ANOTHER SHORT WAVE APPROACHES.
FOR THE PERIOD FROM WEDNESDAY NIGHT THROUGH SUNDAY EXPECT PCPN TO BE
WELL ABOVE NORMAL WITH TEMPS SLIGHTLY BELOW NORMAL.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM...THE RAIN SHIELD WAS GETTING PINCHED OFF TO THE SOUTH
OF ALBANY. VFR CONDITIONS PREVAILED FOR KGFL AND KALB AND WILL
LIKELY DO SO FOR THE REMAINDER OF THE AFTERNOON INTO THE EVENING.
SOME MVFR CLOUDS MIGHT SLIP DOWN THE MOHAWK VALLEY FOR AWHILE THIS
AFTERNOON AND EARLY EVENING AT KALB.
THE RAIN SHOWERS WILL LIKELY CONTINUE AT KPOU UNTIL AROUND 22Z WITH
MVFR CONDITIONS...POSSIBLY BRIEFLY GOING TO IFR CIGS. HOWEVER...THE
THREAT AND DURATION WAS NOT ENOUGH TO INCLUDE ANY MENTION OF IFR IN
THE 18Z TAF ISSUANCES. CONDITIONS WILL IMPROVE AT KPOU AFTER 22Z TO
VFR.
A NORTHWEST WIND WILL ENSUE AROUND 10 KTS...GUSTING TO OVER 20KTS AT
TIMES AT KALB.
TONIGHT...THE CLOUDS WILL BECOME SCATTERED TO FEW. THE WIND WILL
LIGHTEN UP. THE BIG QUESTION IS WHETHER OR NOT FOG WOULD
FORM...ESPECIALLY AT KGFL. MIXING WILL ADVECT COLDER AND DRIER AIR
THROUGH MIDNIGHT. AFTER THAT...A BRIEF RIDGE WILL ALLOW THE WIND TO
MOSTLY DECOUPLE. RIGHT NOW IT APPEARS THAT ANY SATURATION WOULD BE
CONFINED TO THE GROUND AND THEREFORE ANY FOG THAT DOES FORM WOULD BE
EXTREMELY SHALLOW. SO FOR NOW...NO FOG MENTIONED AT ANY OF OUR
STATIONS BUT PLEASE CHECK BACK FOR ANY UPDATES.
OUTLOOK...
TUE-WED...VFR. NO SIG WX.
WED NIGHT-THU...MVFR-IFR. RA LIKELY.
FRI...VFR...CHC -SHRA/-SHSN.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS THROUGH WEDNESDAY...WITH JUST LIGHT QPF
AMOUNTS EXPECTED TODAY WITH THE PASSAGE OF A COLD FRONT...WITH
TOTAL QPF RANGING FROM A TENTH TO A THIRD OF AN INCH...HIGHEST
ACROSS THE SOUTHERN ADIRONDACKS.
HIGH PRESSURE WILL YIELD MAINLY DRY WEATHER TUESDAY THROUGH
WEDNESDAY...EXCEPT FOR SOME LIGHT LAKE EFFECT SNOW WHICH WILL BE
MAINLY CONFINED TO THE WESTERN ADIRONDACKS LATE MONDAY NIGHT INTO
TUESDAY EVENING.
A STORM SYSTEM APPROACHING FROM THE OH VALLEY WEDNESDAY NIGHT MAY
BRING A SOAKING RAINFALL TO THE HSA WED NT INTO THU...WITH RAINFALL
AMOUNTS RANGING FROM A HALF AN INCH TO AN INCH AND A HALF.
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.
&&
$$
AVIATION...HWJIV
