FXUS61 KALY 152143
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
440 PM EST TUE DEC 15 2009
.SYNOPSIS...
AN ARCTIC AIR MASS WILL POUR INTO THE REGION TONIGHT AND WEDNESDAY
IN THE WAKE OF A COLD FRONT. THIS WILL SET THE STAGE FOR WINDY AND
VERY COLD CONDITIONS FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE COMBINATION OF COLD ADVECTION SQUEEZING OUT REMAINING MOISTURE
OVER THE REGION AND LAKE ENHANCED SNOW SHOWERS IN A NORTHWEST FLOW
WILL RESULT IN SCATTERED SNOW SHOWERS TONIGHT FOR MUCH OF THE HIGHER
TERRAIN AND AREAS TO THE SOUTHEAST OF LAKE ONTARIO. AS A RESULT HAVE
FORECAST MAINLY SLIGHT CHANCE POPS FOR LOWER TERRAIN AREAS...AND 30
TO 40 PERCENT ELSEWHERE. NORTHWEST WINDS WILL PICK UP TO 10 TO 20
MPH WITH GUSTS CLOSE TO 30 MPH BY LATE TONIGHT. THIS WILL BRING THE
INITIAL SURGE OF COLD AIR INTO THE REGION TONIGHT WITH LOWS IN THE
TEENS TO MID 20S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE LAKE EFFECT MENTIONED ABOVE WILL BRIEFLY TURN INTO A MORE
WESTERLY DIRECTION ON WEDNESDAY AHEAD OF A REINFORCING SURGE
(SURFACE TROF) OF ARCTIC AIR. THIS COULD BRIEFLY BRING LAKE ENHANCED
SNOW INTO AND DOWN THE MOHAWK VALLEY AS THE MOISTURE MOVES EASTWARD
ALONG THE SURFACE BOUNDARY. THIS COULD RESULT IN A SHORT BURST OF
SNOW IN MANY AREAS...ESPECIALLY FROM THE MOHAWK VALLEY INTO
BERKSHIRE COUNTY...BUT IT SHOULD NOT LAST LONG ENOUGH TO WARRANT ANY
ADVISORIES. THE HIGHEST SNOWFALL FORECAST IS 1 TO 3 INCHES FOR
SOUTHERN HERKIMER COUNTY. HAVE FORECAST LIKELY POPS FOR WEDNESDAY
FROM THE WESTERN PART OF THE MOHAWK VALLEY INTO WESTERN SCHOHARIE
COUNTY...AND CHANCE OR SLIGHT CHANCE POPS ELSEWHERE. HIGHS WEDNESDAY
WILL FEATURE A LARGE RANGE...WITH THE NORTHERN HALF OF THE FORECAST
AREA IN THE MID TEENS TO MID 20S...AND MID 20S TO MID 30S SOUTH
WHERE THE REINFORCING SURGE OF COLD AIR MAY NOT ARRIVE UNTIL LATER
IN THE DAY.
ONCE THE SECONDARY SURFACE TROF MOVES THROUGH...WINDS SHIFT INTO A
NORTHWEST TO NORTH ORIENTATION AND MUCH IF NOT ALL OF THE LAKE
EFFECT IN OUR FORECAST AREAS WILL SHUT DOWN DURING THE WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT PERIOD. HAVE KEPT SOME 40 PERCENT POPS
OVER THE SOUTHWEST PART OF THE FORECAST AREA FOR WEDNESDAY NIGHT AS
LAKE EFFECT WILL LIKELY LINE UP A 310 TO 330 DEGREE ORIENTATION...
THEN ONLY A 20 PERCENT POP IN THIS AREA FOR THURSDAY AND DRY
ELSEWHERE. DRY IN ALL AREAS THURSDAY NIGHT.
BITTER COLD DURING THE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT
PERIOD. LOWS WEDNESDAY NIGHT WILL RANGE FROM AROUND ZERO TO THE MID
TEENS...AND AROUND 5 BELOW ZERO TO AROUND 10 ABOVE FOR THURSDAY
NIGHT. HIGHS THURSDAY WILL ONLY RANGE FROM AROUND 10 TO THE MID 20S.
DURING MOST OF THIS PERIOD SURFACE WINDS WILL BE 10 TO 20 MPH WITH
GUSTS TO 30 MPH...SO THERE COULD BE WIND CHILL ISSUES TO DEAL
WITH...ALTHOUGH CURRENT APPARENT TEMP GRIDS INDICATE WIND CHILL
VALUES WILL GENERALLY REMAIN JUST BELOW THRESHOLD LEVELS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AT THE START OF THE EXTENDED PERIOD...850 HPA TEMPS WILL AVERAGE -6
TO -12 DEGREES C FOR FRIDAY INTO SATURDAY...ALLOWING FOR CONTINUED
CHILLY...BUT DRY CONDITIONS. INVERSION HEIGHTS WILL BE RATHER LOW
AND THE FLOW OF AIR WILL BE A N-NW DIRECTION...SO DO NOT EXPECT ANY
LAKE EFFECT TO OCCUR AT ALL IN OUR AREA. MAX TEMPS WILL GENERALLY BE
IN THE 20S TO NEAR 30 IN THE MID HUDSON VALLEY...WITH TEENS AND
SINGLE DIGITS AT NIGHT.
THE TEMPS WILL START TO MODERATE A BIT FOR SUNDAY THROUGH
TUESDAY...WITH HIGHS RETURNING BACK INTO THE LOWER TO MIDDLE 30S IN
THE VALLEYS. PIECES OF VORTICITY ROTATING AROUND AN UPPER LOW OVER
THE CANADIAN MARITIMES MAY ALLOW FOR A FEW SNOW SHOWERS FOR LATE SAT
NIGHT INTO MONDAY...MAINLY DOWNWIND OF LAKE ONTARIO WHERE SOME LAKE
ENHANCEMENT CAN OCCUR.
IT/S IMPORTANT TO NOTE THAT THE BOTH THE 12 UTC GFS/ECMWF/GGEM
DEVELOP A STORM SYSTEM AT SOME POINT SAT INTO SUN IN THE GULF OF
MEXICO...BUT TRACK THIS LOW PRESSURE SYSTEM NORTHEASTWARD WELL
OFFSHORE AND EAST OF THE REGION. A FEW 12 UTC GEFS MEMBERS ACCORDING
TO THE PLUME DIAGRAM DO BRING THIS STORM CLOSE ENOUGH TO GIVE SOME
APPRECIABLE QPF...BUT THESE SEEM LIKE THE OUTLIERS. AT THIS
POINT...IT SEEMS THE BEST CHC OF SEEING ANY SNOWFALL OVER THE
WEEKEND INTO EARLY NEXT WEEK MAY BE DUE TO VORTICITY MAXES ROTATING
AROUND THE LARGE UPPER LOW SITUATED OVER THE REGION...BUT WOULD NOT
EXPECT MUCH QPF AT ALL WITHOUT A GULF OR ATLANTIC MOISTURE
CONTRIBUTIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
FRONT MOVING THROUGH THE AREA CURRENTLY WITH WESTERLY WINDS SOON TO
MIX DOWN WITH GUSTS INCREASING IN THE MOHAWK VALLEY. WHEN WINDS
START TO MIX DOWN...VSBYS WILL INCREASE TO VFR AT KALB. OTHERWISE
VFR CONDITIONS EXPECTED THROUGH THE REST OF THE PERIOD AT ALL
TERMINALS.
THE AFOREMENTIONED FRONT WILL FILTER IN COLDER AIR ALLOWING FOR LAKE
EFFECT SNOW SHOWERS TO AFFECT KALB AFTER 06Z WITH WINDS CHANNELING
DOWN THE MOHAWK. HAVE INCLUDED VCSH FROM 06Z ON FOR KALB. WINDS WILL
REMAIN OUT OF THE WEST TO NORTHWEST INCREASING IN SPEED WEDNESDAY
AFTERNOON.
OUTLOOK...
WED-THU...VFR...SOME SHSN DOWNWIND FROM LAKE ONTARIO. WINDY.
FRI...VFR...NO SIG WX.
SAT...MAINLY VFR...SLGT CHC -SHSN.
&&
.HYDROLOGY...
ONLY LIGHT PRECIP IS EXPECTED OVER THE NEXT 24 HOURS...MAINLY ACROSS
NORTHERN BASINS...WHERE LIQUID EQUIVALENT AMOUNTS SHOULD GENERALLY
REMAIN UNDER ONE QUARTER OF AN INCH...IN THE FORM OF SNOW. THIS WILL
HAVE LITTLE OR NO IMPACT ON AREA RIVERS/STREAMS. GENERALLY DRY
CONDITIONS ARE THEN EXPECTED THROUGH AT LEAST SATURDAY.
AS DAILY MEAN TEMPERATURES FALL WELL BELOW FREEZING WED-FRI...ICE
FORMATION IS EXPECTED ON ALL AREA RIVERS/STREAMS WITH PERHAPS THE
EXCEPTION OF THE LARGER STEM HUDSON.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM
NEAR TERM...GJM
SHORT TERM...GJM
LONG TERM...KSL
AVIATION...KGS
HYDROLOGY...KSL
