FXUS61 KALY 292352
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
650 PM EST SUN NOV 29 2009
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE REGION TONIGHT AND MONDAY
BRINGING RAIN AND SNOW SHOWERS TO THE AREA. A MORE SEASONABLE
AIRMASS WILL BE USHERED IN BEHIND THIS SYSTEM WITH SOME LAKE EFFECT
SNOW EXPECTED ACROSS PORTIONS THE WESTERN ADIRONDACKS MONDAY NIGHT
AND TUESDAY. HIGH PRESSURE WILL BUILD IN TUESDAY NIGHT AND SHOULD
DOMINATE OUR WEATHER WEDNESDAY. WIDESPREAD PRECIPITATION...MAINLY
RAIN...IS EXPECTED WEDNESDAY NIGHT AND THURSDAY AS STORM SYSTEM
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /THROUGH MONDAY/...
THE RIDGE OVER THE AREA WILL SHIFT EAST OFFSHORE THIS EVENING AND A
LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL MOVE EAST ACROSS THE
LOCAL AREA LATE TONIGHT AND MONDAY MORNING. CLOUDS WILL BE ON THE
INCREASE THIS EVENING. MOST OF THE PRECIPITATION ASSOCIATED WITH THE
SYSTEM WILL OCCUR ALONG AND BEHIND THE COLD FRONT WITH THE UPPER
LEVEL SUPPORT WHICH LAGS. LONGWAVE TROUGH DIGS IN OVER REGION DURING
THE DAY MONDAY. TEMPERATURES WILL DROP DURING THE AFTERNOON IN THE
COLD AIR ADVECTION. THE 850 MB 0C ISOTHERM REACHES THE MID/LOWER
HUDSON VALLEY BY EARLY AFTERNOON AND MOVES OFFSHORE...SOUTH OF LONG
ISLAND...BY EARLY EVENING.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
ADDITIONAL SHORT WAVE ENERGY DIVES INTO THE TROUGH MONDAY NIGHT AS
SURFACE HIGH TRIES TO BUILD IN. THE UPPER TROUGH AXIS MOVES TO OUR
EAST TUESDAY MORNING WITH CYCLONIC FLOW ACROSS THE REGION. LAKE
ONTARIO SURFACE WATER TEMPERATURE IS IN THE UPPER 40S AND WITH THE
COLDER MORE SEASONABLE AIRMASS BEING USHERING IN SOME LAKE EFFECT
SHOWERS ARE EXPECTED ACROSS PORTIONS OF THE WESTERN ADIRONDACKS WITH
WESTERLY LOW LEVEL FLOW TUESDAY. LIGHT SNOW ACCUMULATIONS OF 1 TO 2
INCHES ARE EXPECTED AT THIS TIME. THE LAKE EFFECT WILL GET CUT OFF
AS RIDGING BUILDS AT THE SURFACE AND ALOFT TUESDAY NIGHT. THE RIDGE
IS EXPECTED TO DOMINATE OUR WEATHER WEDNESDAY WITH A STORM
APPROACHING FROM THE SOUTH.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DETERMINISTIC LONG RANGE GUIDANCE /ECMWF...GFS...CANADIAN GGEM/
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. THIS SYSTEM WILL BE UTILIZING GULF OF MEXICO
MOISTURE. THE EXACT TRACK OF THE INTENSIFYING LOW PRESSURE SYSTEM
IN THE SOUTHWEST FLOW ALOFT IS STILL VARIABLE FROM THE
GUIDANCE...THOUGH THE 12 GEFS MEAN BRINGS THE LOW ACROSS E-CNTRL PA
AND OVER THE CAPITAL REGION BTWN 12Z-18Z THU. THERE IS QUITE A BIT
OF SPREAD WITH A FEW MEMBERS AS FAR WEST AS ERN MI...AND AS FAR
SOUTH AND EAST TO THE DELMARVA REGION. THE ENSEMBLE MEAN MSLP OF
THE SFC CYCLONE IS 988 HPA...SO A DEEPENING AND INTENSIFYING WAVE IS
IMPLIED. HOWEVER...THERE IS NOT A COLD CANADIAN ANTICYCLONE TO THE
NORTH ENTRENCHING COLD AIR AHEAD OF THE WAVE. THE THERMAL PROFILES
ARE WARM FOR PREDOMINANTLY AN ALL RAIN EVENT FOR THE HEART OF THE
EVENT. A MOISTURE RICH LOW LEVEL BAROCLINIC ZONE SHOULD YIELD SOME
PERIODS OF RAIN /POSSIBLY MODERATE TO HVY AT TIMES/ WEDNESDAY NIGHT
INTO THURSDAY...AND WE HAVE ADDRESSED THE BETTER CHANCES OF RAIN
WITH LIKELY POPS FCST AREA WIDE ON THU.
THU NIGHT INTO FRI...THE STRONG SFC WAVE ACCELERATES NORTHEAST AS IT
REMAINS AN OPEN WAVE ALOFT. STRONG COLD AIR ADVECTION OCCURS IN THE
WAKE OF THE SYSTEM WITH SOME LAKE ENHANCED PCPN POSSIBLE FOR THE WRN
PORTION OF THE FCST AREA. H850 TEMPS TUMBLE TO AROUND -10C FOR THE
BULK OF THE FCST AREA.
SATURDAY...BROAD CYCLONIC FLOW PERSISTS TO OPEN THE WEEKEND WITH
COLD AIR FUNNELING SOUTHEAST TOWARDS THE REGION FROM THE S-CNTRL
ONTARIO. SOME LAKE EFFECT -SHSN/S WILL PERSIST WEST OF THE HUDSON
RIVER VALLEY.
SATURDAY NIGHT INTO SUNDAY...THE LOW LEVEL FLOW BEGINS TO SHIFT AND
BECOME ANTICYCLONIC WITH SFC HIGH PRESSURE NOSING IN FROM THE OH
VALLEY/MID ATLANTIC REGION. TEMPS WILL MODERATE TO NEAR NORMAL
VALUES FOR EARLY DEC. MOST OF THE FCST AREA LOOKS LIKE IT WILL HAVE
A FAIRLY DRY WEEKEND AT THIS POINT IN TIME.
OVERALL...PCPN LOOKS ABOVE NORMAL BASED ON THE STORM SYSTEM FOR
THU...AND TEMPS WILL BE NEAR NORMAL OR SLIGHTLY BELOW NORMAL FOR THE
STRETCH.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
MID AND HIGH LEVEL CLOUDS WERE OVERSPREADING THE REGINO THIS
EVENING AS A COLD FRONT APPROACHES THE AREA. VFR FLIGHT CONDITIONS
WILL CONTINUE UNTIL SEVERAL HOURS PAST MIDNIGHT WHEN STARTING AROUND
08Z-010Z CIGS AND VISBY WILL DETERIORATE TO MVFR FROM NORTHWEST TO
SOUTHEAST...WITH RAIN SHOWERS MOVING IN FROM THE NORTHWEST STARTING
BETWEEN 08Z AND 10Z. AT THIS POINT IT APPEARS THAT THE HUDSON VALLEY
TAF SITES WILL STAY MVFR THROUGH MUCH OF THE DAY MONDAY...IN RAIN
SHOWERS AND MIST. CONDITIONS WILL IMPROVE LATE IN THE AFTERNOON
AS THE SHOWERS END AND CLOUD BASES GO ABOVE VFR MINIMUMS. IFR
CIGS ARE LIKELY TO BE ENCOUNTERED ACROSS THE HIGHER TERRAIN EAST
AND WEST OF THE HUDSON VALLEY DURING MUCH OF THE DAY.
WINDS WILL BE NEAR CALM UNTIL SHORTLY BEFORE DAYBREAK...START
LIGHT FROM THE SOUTHWEST...THEN GRADUALLY INCREASE TO BETWEEN
6 AND 8 KNOTS AND VEER AROUND TO THE NORTHWEST BY MID AFTEROON.
OUTLOOK...
MON NIGHT-TUE...VFR WITH MVFR IN LAKE EFFECT -SHSN WRN ADIRONDACKS.
TUE NIGHT-WED...VFR...NO SIG WX.
WED NIGHT- THU...MVFR-IFR. RA LIKELY.
FRI...VFR...CHC -SHRA/-SHSN.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT FIVE DAYS. A
COLD FRONT AND A WEAK WAVE OF LOW PRESSURE WILL BRING LIGHT PCPN TO
THE HYDRO SERVICE AREA /HSA/ SUNDAY NIGHT THRU MONDAY IN THE FORM OF
RAIN AND SNOW SHOWERS. TOTAL QPF WILL RANGE FROM A TENTH TO A THIRD
OF AN INCH.
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 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.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA
SHORT TERM...IAA
LONG TERM...WASULA
AVIATION...RCK
HYDROLOGY...WASULA
