FXUS61 KALY 262118
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
418 PM EST SAT DEC 26 2009
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE SOUTH OF LONG ISLAND THIS
EVENING WILL MOVE SLOWLY NORTH INTO NORTHERN NEW ENGLAND SUNDAY
AFTERNOON...AND THEN INTO THE CANADIAN MARITIMES SUNDAY NIGHT.
SUNDAY NIGHT INTO MONDAY NIGHT A MID LEVEL DISTURBANCE...COLD FRONT
AND UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION BRINGING SNOW
SHOWERS...AND IN ITS WAKE USHER IN MUCH COLDER AIR. HIGH PRESSURE
WILL THEN BUILD IN FROM THE MIDWEST TO THE NORTHEAST DURING THE MID
WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 330 PM EST...LIGHT PRECIP IS ONCE AGAIN DEVELOPING FROM S TO
N...IN ASSOCIATION WITH ENHANCED LOW LEVEL CONVERGENCE TO THE N OF
DEVELOPING SECONDARY LOW...AND AHEAD OF APPROACHING OCCLUDED FRONT.
ACCORDING TO LATEST MADIS OBS...AND SPOTTER REPORTS...TEMPS AT
ELEVATIONS 1000 FT AND ABOVE ARE STILL RUNNING NEAR OR JUST BELOW
FREEZING FROM THE SCHOHARIE VALLEY N INTO THE WESTERN MOHAWK
VALLEY/SOUTHERN DACKS...AS WELL AS INTO THE BERKS AND SOUTHERN VT.
THUS...AS THE PRECIP REDEVELOPS...WE EXPECT FREEZING RAIN/DRIZZLE
FOR THESE HIGHER ELEVATIONS...WITH PLAIN RAIN/DRIZZLE EXPECTED BELOW
1000 FT. ADDITIONAL ICE ACCRETION COULD BE 0.10-0.25 IN THESE HIGHER
ELEVATIONS. SINCE ISOLATED AREAS OF SOUTHERN HERKIMER HAVE ALREADY
RECEIVED AROUND 0.4 ICE ACCRETION...AND WITH AT LEAST ANOTHER TENTH
EXPECTED...WE HAVE RAISED THE PREVIOUS ADV TO AN ICE STORM WARNING.
STRONG E/SE WINDS IN THIS SMALL AREA WILL LIKELY ENHANCE THE CHANCES
FOR AT LEAST SOME POWER OUTAGES DUE TO THE WIND...AND WEIGHT OF ICE
ON TREE LIMBS.
TEMPS SHOULD GRADUALLY RISE OVERNIGHT...ESP TOWARD AND AFTER
MIDNIGHT. THUS...FREEZING RAIN POTENTIAL SHOULD DIMINISH ACROSS THE
HIGHER ELEVATIONS LATER TONIGHT. PERIODS OF RAIN WILL PERSIST
ELSEWHERE...IN ADDITION TO THE POSSIBILITY OF SOME AREAS OF FOG
GIVEN THE COLD GROUND AND SNOW COVER.
ALTHOUGH MOST RAIN SHOULD REMAIN LIGHT...A PERIOD OF MODERATE RAIN
WILL BE POSSIBLE LATER THIS EVENING THROUGH MIDNIGHT FOR AREAS
MAINLY S/E OF THE CAPITAL REGION.
E/SE WINDS WILL CONTINUE TO INCREASE...ESP FOR HIGHER ELEVATIONS
WITHIN THE TACONICS/SOUTHERN GREENS/BERKS...WHERE E/SE WINDS TEND TO
MIX DOWN MORE READILY. THUS...WIND ADVISORIES WILL REMAIN IN THESE
AREAS...WITH SOME GUSTS POSSIBLY REACHING 50 MPH...ESP TOWARD AND
JUST AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
VERY LITTLE PRECIPITATION EXPECTED TO OCCUR ON SUNDAY AS DRY SLOT
MOVES INTO FA WITH LOW LIFTING INTO NORTHERN NEW ENGLAND. WILL
KEEP ANY LINGERING PCPN MAINLY IN THE FORM OF LIGHT SNOW OR RAIN
SHOWERS CONFINED TO THE MORNING HOURS. HIGHS ON SUNDAY IN THE MID
30S TO MID 40S.
FOR THE PERIOD FROM SUNDAY NIGHT THROUGH MONDAY NIGHT A VERY
ACTIVE PATTERN EXPECTED WHICH WILL BE MAINLY DUE TO MID AND UPPER
LEVEL FEATURES. CLOSED H5 LOW AND ASSOCIATED VORT AXIS LIFT FROM
EASTERN GREAT LAKES SUNDAY EVENING ACROSS THE TUG HILL MONDAY
MORNING AND INTO NORTHERN NEW ENGLAND MONDAY AFTERNOON. BEHIND
THIS A SECOND UPPER TROUGH WITH YET ANOTHER VORT AXIS AND AN ARCTIC
COLD FRONT WILL MOVE THROUGH THE REGION MONDAY NIGHT. EXPECT THAT
MOST AREAS WILL SEE MEASURABLE SNOW WITH A FEW INCHES OF
ACCUMULATION...EXCEPT FOR THE WESTERN ADIRONDACKS WHERE ADVISORY
LEVEL CRITERIA SNOW MAY OCCUR OVER A 36 HOUR PERIOD. HAVE INCLUDED
MENTION OF THIS IN HWO AND USED CAR SNOW TOOL FOR SNOW AMOUNTS IN
GRIDS. ACROSS THE WESTERN ADIRONDACKS EXPECT QPF AMOUNTS FROM
SUNDAY NIGHT THROUGH MONDAY NIGHT OF A THIRD TO AROUND HALF AN
INCH WITH A SNOW TO LIQUID RATIO OF 17-20 TO 1. EXPECT LOWS SUNDAY
NIGHT IN THE UPPER TEENS TO UPPER 20S WITH HIGHS ON MONDAY
GENERALLY IN THE UPPER 20S TO MID 30S AND LOWS MONDAY NIGHT FROM
AROUND ZERO NORTHWEST TO AROUND 20 SOUTHEAST. MONDAY NIGHT WIND
CHILLS MAY ALSO BE AN ISSUE ESPECIALLY ACROSS HIGHER TERRAIN AS
NORTHWEST WINDS WILL INCREASE TO 15 TO 25 MPH WITH GUSTS AS HIGH
AS 40 MPH IN THE WAKE OF THE ARCTIC COLD FRONT...SO HAVE INCLUDED
MENTION IN HWO.
ON TUESDAY EXPECT A MAINLY DRY BUT VERY COLD DAY WITH THE
POSSIBILITY OF TEMPS REMAINING STEADY OR SLOWLY FALLING DURING THE
AFTERNOON. WIND CHILLS WILL ONCE AGAIN BE AN ISSUE AND HAVE
INCLUDED IN HWO. HIGHS WILL STRUGGLE TO REACH SINGLE DIGITS TO
LOWER 20S WITH NORTHWEST WINDS OF 15 TO 25 MPH WITH GUSTS 30
TO 40 MPH. H8 TEMPS ON TUESDAY EXPECTED TO BE -16 C SOUTHEAST TO
-24 C NORTHWEST DURING THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
DRY BUT VERY COLD WEATHER IS EXPECTED TUESDAY NIGHT AND WEDNESDAY
WITH WIND CHILLS BEING AN ISSUE MAINLY ACROSS THE HIGHER TERRAIN.
WILL INCLUDE MENTION OF THIS IN THE HWO FOR NOW. EXPECT LOWS
TUESDAY NIGHT TO RANGE FROM -10 FAR NORTHWEST TO +10 FAR SOUTHEAST
WITH HIGHS ON WEDNESDAY IN THE MID TO UPPER TEENS NORTH TO UPPER
20S SOUTHEAST.
A CLIPPER TYPE SYSTEM IS EXPECTED TO MOVE INTO THE UPPER GREAT
LAKES WEDNESDAY NIGHT AND LIFT A WARM FRONT INTO OUR REGION AS A
SECOND LOW PRESSURE SYSTEM STARTS TO DEVELOP ALONG THE SOUTHEAST
COAST AND THEN TRACK NORTHEAST FRIDAY INTO SATURDAY. THERE IS
ALLOT OF UNCERTAINTY AS THE EXACT POSITION OF THIS SYSTEM...BUT
THE ECMWF HAS BEEN CONSISTENT FOR SEVERAL MODEL RUNS WITH AN EAST
COAST SYSTEM. WILL AT THIS POINT GRADUALLY INCREASE POPS FROM
SLIGHT CHANCE TO LOW CHANCE POPS WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT TO CHANCE POPS FOR FRIDAY THROUGH SATURDAY. AIR MASS LOOKS TO
BE SUFFICIENTLY COLD AT THIS POINT FOR ALL SNOW...BUT AMOUNTS VERY
UNCERTAIN THIS FAR OUT. HIGHS WILL MAINLY BE IN THE 20S TO LOWER
30S THURSDAY...FRIDAY AND SATURDAY WITH LOWS WEDNESDAY NIGHT ZERO
TO 15 ABOVE AND UPPER SINGLE DIGITS TO AROUND 20 THURSDAY NIGHT
AND FRIDAY NIGHT.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
EXPECTING PERIODS OF RAIN TO INCREASE AND FILL IN AT THE AIRPORTS AS
LOW PRESSURE MOVES UP THE MID-ATLANTIC COAST. WITH TEMPERATURES
STAYING ABOVE FREEZING OVERNIGHT AS MILD AIR BLOWS OVER THE ICY
SURFACES...CONDITIONS WILL DETERIORATE TO IFR VSBY...ESPECIALLY AT
GFL AND ALB ONCE THE RAINFALL IS IN PLACE. CIGS WILL ALSO LOWER TO
IFR AS THE LOW GETS CLOSER.
WIND SHEAR BECOMES AN ISSUE AFTER 00Z WITH A SOUTHEASTERLY FLOW
THROUGH THE COLUMN. AS THE LOW AND A SURFACE TROF LIFT THRU OUR
AREA...MIX DOWN OCCURS AROUND DAYBREAK...AND SURFACE WINDS SWING TO
WESTERLY...INCREASING A LITTLE. BUT THEY REMAIN SOMEWHAT LIGHT
DURING THE LATE MORNING PERIOD...DURING WHICH TIME CONDITIONS BEGIN
TO IMPROVE TOWARD MVFR AND VFR.
OUTLOOK...
SUN AFTN-SUN NGT...VFR...NO SIG WX.
MON-MON NGT...VFR...CHC MVFR/IFR -SHSN.
TUE-THU...VFR...NO SIG WX.
&&
.HYDROLOGY...
QPF AMOUNTS WILL GENERALLY BE A TENTH TO A QUARTER OF AN INCH
THROUGH SUNDAY...AFTER WHICH ANY ADDITIONAL PRECIPITATION WILL BE
IN THE FORM OF SNOW THROUGH EARLY NEXT WEEK. SUNDAY LOOKS TO BE
THE WARMEST DAY WITH HIGHS IN THE MID 30S TO MID 40S WHICH WILL
RESULT IN SOME SNOW MELT...BUT WITH BASIN AVERAGE QPF AMOUNTS
GENERALLY A THIRD TO TWO THIRDS OF AN INCH EXPECT ONLY A RISE OF
SEVERAL FEET ON THE RIVERS WHICH WILL MAINLY OCCUR ACROSS SOUTHERN
PORTIONS OF THE HSA. THE NEXT SYSTEM FROM LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT IS EXPECTED TO BRING SNOW WITH MOST AREAS
SEEING A FEW INCHES...EXCEPT HIGHER AMOUNTS ARE POSSIBLE ACROSS
THE WESTERN ADIRONDACKS. DRY WEATHER WILL RETURN FOR TUESDAY INTO
WEDNESDAY AND WITH VERY COLD AIR IN PLACE ACROSS THE
REGION...RIVERS IN MOST PLACES WILL ADD SEVERAL INCHES OF ICE.
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...WIND ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ054-061-084.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ033-042-
082.
FREEZING RAIN ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ039-040-
047.
ICE STORM WARNING UNTIL 6 AM EST SUNDAY FOR NYZ038.
MA...WIND ADVISORY UNTIL 6 AM EST SUNDAY FOR MAZ001-025.
FREEZING RAIN ADVISORY UNTIL 6 AM EST SUNDAY FOR MAZ001-025.
VT...WIND ADVISORY UNTIL 6 AM EST SUNDAY FOR VTZ013-014.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...11/SNYDER
NEAR TERM...KL
SHORT TERM...11
LONG TERM...11
AVIATION...ELH
HYDROLOGY...11
