November 11, 2013 Forecast Discussion
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000
FXUS61 KALY 111737
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1237 PM EST MON NOV 11 2013

.SYNOPSIS…
HIGH PRESSURE OVER THE REGION WILL WEAKEN TODAY AS A STRONG COLD
FRONT APPROACHES FROM THE NORTHWEST. THE COLD FRONT WILL CROSS
REGION LATE TODAY AND THIS EVENING ACCOMPANIED BY RAIN AND SNOW
SHOWERS. A MUCH COLDER AIR MASS WILL BE USHERED INTO THE REGION
WITH ITS PASSAGE. HIGH PRESSURE WILL BUILD IN AND IS EXPECTED TO
DOMINATE INTO THE WEEKEND WITH DRY WEATHER. TEMPERATURES WILL
EVENTUALLY MODERATE TO ABOVE NORMAL BY THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/…
AS OF 1000 AM EST…TRANQUIL CONDITIONS EXIST ACROSS THE AREA LATE
THIS MORNING…AS A SURFACE RIDGE AXIS IS CURRENTLY POSITIONED
ACROSS EAST-CENTRAL NY. HOWEVER…A COLD FRONT IS PUSHING THROUGH
THE CENTRAL GREAT LAKES AND WILL APPROACH OUR REGION LATE TODAY.
CLOUDS WILL INCREASE AHEAD OF THIS SYSTEM…WITH RAIN/SNOW SHOWERS
REACHING THE WESTERN ADIRONDACKS BY MID AFTERNOON. THE SHOWERS
WILL SPREAD SOUTH AND EAST FROM THERE LATE THIS AFTERNOON AND
ESPECIALLY THIS EVENING.

MODEL GUIDANCE IS IN GOOD AGREEMENT WITH MOVEMENT AND TIMING OF THE
MAIN FEATURES. A STACKED LOW WILL MOVE ACROSS EASTERN CANADA
SWEEPING A STRONG COLD FRONT THE REGION TODAY AND TONIGHT.
AT THE SURFACE…A RIDGE IS CRESTING OVER THE REGION…IT WILL
WEAKEN AS THE DAY PROGRESSES WITH THE AXIS SHIFTING OFF THE EAST
THIS AFTERNOON.

LIGHT ACCUMULATIONS OF SNOW MAINLY ACROSS THE HIGHER TERRAIN TONIGHT
AND TURNING MUCH COLDER. A STRONG COLD FRONT WILL SWEEP ACROSS
THE FORECAST AREA MAINLY BETWEEN 18Z/MON AND 06Z/TUE. THE
DEEPENING AND AMPLIFYING LONGWAVE TROUGH ASSOCIATED WITH THE FRONT
WILL PUSH THE BOUNDARY OFF THE EAST COAST BY DAYBREAK TUESDAY.

THE BOUNDARY WILL FEATURE A TIGHT THERMAL GRADIENT…STRONG LOW
LEVEL COLD ADVECTION WILL OCCUR IN ITS WAKE…BY 12Z/TUESDAY 850 MB
TEMPERATURES WILL HAVE DROPPED TO -9 TO -13 DEGREES CELSIUS ACROSS
THE FORECAST AREA. THE PRECIPITATION WILL OCCUR MAINLY BEHIND THE
FRONT DURING THE EVENING INTO THE EARLY MORNING HOURS. AS THE COLD
FILTERS IN RAIN WILL CHANGE TO SNOW ACROSS THE FORECAST AREA. LIGHT
ACCUMULATIONS OF SNOW ARE EXPECTED ACROSS THE HIGHER TERRAIN WITH
THE HIGHEST AMOUNTS OF 2 TO 4 INCHES ACROSS THE WESTERN ADIRONDACKS
WHERE THE HIGHER QPF IS EXPECTED AND WHERE THE CHANGE OVER TO SNOW
WILL OCCUR FIRST.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/…
COLD…COLD…COLD WITH TEMPERATURES 10 TO 20 DEGREES BELOW
NORMAL.

THE SHARP UPPER TROUGH WILL MOVE ACROSS THE EASTERN UNITED STATES
EVENTUALLY MOVING OFF THE EAST COAST WEDNESDAY MORNING. THE
COLDEST AIR WILL ARRIVE LATE TUESDAY NIGHT/EARLY WEDNESDAY MORNING.
THE NAM IS COLDER AT 850 MB TEMPERATURES BY A COUPLE DEGREES WITH
-15 TO -17 DEGREE COLD POOL PASSING OVERHEAD. AT THE SURFACE…A
STRONG COLD HIGH PRESSURE ORIGINATING FROM CANADA WILL SINK SOUTHWARD
ACROSS THE PLAINS AND EXPAND EASTWARD ACROSS OUR REGION.

HAVE UNDERCUT MOS GUIDANCE A BIT FOR TUESDAY…TUESDAY NIGHT AND
WEDNESDAY. BRISK NORTHWESTERLY WINDS ALONG WITH THE COLD AIR MASS
WILL RESULT IN WIND CHILL VALUES ONLY IN THE 20S DURING THE
AFTERNOON BOTH DAYS. EXPECTING LOWS TO DROP INTO MAINLY THE TEENS
TUESDAY NIGHT WITH SINGLE DIGITS ACROSS THE HIGHER TERRAIN OF THE
SOUTHERN ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS.

TEMPERATURES WILL BEGIN TO MODERATE ALOFT WEDNESDAY. ALSO THE
SURFACE RIDGE AXIS WILL SHIFT TO OUR SOUTH ALLOWING A SOUTHWESTERLY
FLOW TO DEVELOP. THUS…WEDNESDAY NIGHT WILL NOT BE AS COLD AS
TUESDAY NIGHT BUT STILL BELOW NORMAL.

LAKE EFFECT WILL BE SHORT LIVED TUESDAY AS RIDGING IN THE LOWER
LEVELS QUICKLY BUILDS IN AND ITS FOCUS WILL BE ACROSS CENTRAL NEW
YORK DUE THE NORTHWEST FLOW.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/…
THE EXTENDED FORECAST BEGINS WITH TRANQUIL WEATHER WITH A BROAD
ANTICYCLONE IN CONTROL INTO THE FIRST PART OF THE WEEKEND…THEN
UNSETTLED WEATHER RETURNS TO CLOSE TO THE WEEKEND AND OPEN UP NEXT
WEEK.

THE WPC GUIDANCE WAS FAVORED IN THE LONG TERM. A BROAD ANTICYCLONE
WILL BE RIDGING IN FROM THE SOUTHEAST AND MID ATLANTIC REGION ON
THURSDAY. H850 TEMPS REBOUND TO +3 TO +6C WITH THE W/SW FLOW
ALOFT. THE SUBSIDENCE FROM THE RIDGE WILL YIELD LOTS OF SUNSHINE
AND TEMPS CLOSE TO NORMAL WITH HIGHS IN THE M40S TO NEAR 50F IN MANY
OF THE VALLEY LOCATIONS…AND U30S TO M40S OVER THE HILLS AND MTNS.
LOWS THU NIGHT WITH NEAR IDEAL RADIATIONAL COOLING CONDITIONS WILL
BE IN THE 20S.

FRIDAY INTO SATURDAY…THE SFC ANTICYCLONE GRADUALLY MOVES OFF THE
EAST COAST AND A RETURN FLOW OF MILDER AIR SETS UP FOR ERN NY AND
WRN NEW ENGLAND. LOW AND MID LEVEL HEIGHTS GRADUALLY RISE…AND A
SW FLOW SETS UP OVER THE NORTHEAST. THE ECMWF/GFS HINTS AT A WEAK
BACKDOOR COLD FRONT OR NRN STREAM DISTURBANCE IMPACTING THE REGION
LATE SATURDAY. OUR FORECAST REFLECTS AN INCREASE OF SOME CLOUDS
LATE IN THE DAY AND PERHAPS SOME SPRINKLES WITH FAIRLY DRY LOW
LEVELS IN PLACED. THE DISTURBANCE LACKS MUCH MOISTURE CONVERGENCE
TOO. TEMPS MODERATE INTO THE U40S TO L50S IN THE VALLEYS BOTH
DAYS…AND 40S OVER THE MTNS.

SATURDAY NIGHT INTO SUNDAY…THE SFC ANTICYCLONE DRIFTS NEAR THE
CANADIAN MARITIMES AND NOVA SCOTIA WITH AN IMPULSE IN THE SOUTHWEST
FLOW BRINGING A SLIGHT OR LOW CHC OF SHOWERS LATE IN THE DAY ON
SUNDAY. THIS DISTURBANCE WILL BE IN ADVANCE OF A WARM FRONT TIED TO
A LOW PRESSURE SYSTEM MOVING INTO THE GREAT LAKES REGION…AND
ONTARIO. AFTER LOWS IN THE 30S…MAX TEMPS SHOULD BE A SOLID 5 TO 10
DEGREES ABOVE NORMAL WITH HIGHS IN THE LOWER TO M50S IN THE
VALLEYS…AND OVER THE HILLS. EXPECT MID AND U40S OVER THE MTNS.

OVERALL…TEMPS LOOK TO AVERAGE ABOVE NORMAL WITH PCPN BELOW NORMAL
IN THE LONG TERM.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/…
A STRONG COLD FRONT WILL APPROACH FROM THE EASTERN GREAT LAKES
REGION AND ST LAWRENCE RIVER VALLEY LATE THIS AFTERNOON…AND
CROSS OUR REGION THIS EVENING INTO THE OVERNIGHT…BRINGING A
PERIOD OF RAIN AND SNOW SHOWERS.

VFR CONDITIONS TO PREVAIL THROUGH AT LEAST THE FIRST 6 HOURS OF
THE TAF PERIOD…THEN A 2-4 HOUR PERIOD OF MVFR EXPECTED
ASSOCIATED WITH RAIN/SNOW SHOWERS ALONG AND JUST BEHIND THE COLD
FRONT. BEST ESTIMATE FOR TIMING OF ONSET OF PRECIP IS AROUND 02Z
AT KGFL…03Z AND KALB/KPSF…AND 06Z AT KPOU. WILL MENTION MIXED
RAIN/SNOW FOR KALB/KGFL/KPOU…WITH PRIMARILY SNOW AT KPSF.
TOWARDS THE END OF THE PRECIP A COMPLETE CHANGEOVER TO SNOW MAY
OCCUR AT KALB/KGFL WITH A DUSTING TO A FEW TENTHS OF AN INCH
POSSIBLE. VFR CONDITIONS WILL RETURN BETWEEN 06Z-09Z
WEDNESDAY…WITH DRIER AIR WORKING IN BEHIND THE COLD FRONT.

WINDS WILL GENERALLY BE SOUTHWEST AROUND 7-10 KT INTO THE EVENING
HOURS…THEN ABRUPTLY SHIFT TO THE NORTHWEST BEHIND THE COLD FRONT
OVERNIGHT AT 10-15 KT WITH GUSTS OF 20-25 KT POSSIBLE.

OUTLOOK…
TUESDAY NIGHT-SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.FIRE WEATHER…
HIGH PRESSURE OVER THE REGION WILL WEAKEN TODAY AS A STRONG COLD
FRONT APPROACHES FROM THE NORTHWEST. THE COLD FRONT WILL CROSS
REGION THIS AFTERNOON AND EVENING ACCOMPANIED RAIN AND SNOW SHOWERS.
A MUCH COLDER AIR MASS WILL BE USHERED INTO THE REGION WITH ITS
PASSAGE. HIGH PRESSURE WILL BUILD IN AND IS EXPECTED TO DOMINATE
INTO THE WEEKEND WITH DRY WEATHER. TEMPERATURES WILL EVENTUALLY
MODERATE TO ABOVE NORMAL BY THE END OF THE WEEK.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED THIS WEEK. A STRONG COLD FRONT MOVE
ACROSS THE REGION THIS AFTERNOON AND EVENING ACCOMPANIED BY RAIN AND
SNOW SHOWERS. QPF AMOUNTS OF GENERALLY A TENTH OF AN INCH OR LESS
ARE EXPECTED ACROSS MOST OF THE FORECAST AREA. HIGHER AMOUNTS UP TO
ABOUT A THIRD OF AN INCH ARE EXPECTED ACROSS THE WESTERN ADIRONDACKS
WHICH WILL FALL MOSTLY AS SNOW. IN THE WAKE OF THE COLD FRONT HIGH
PRESSURE WILL BUILD IN AND IS EXPECTED TO DOMINATE OUR WEATHER INTO
THE WEEKEND.

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/JPV
SHORT TERM…IAA
LONG TERM…WASULA
AVIATION…JPV
FIRE WEATHER…IAA
HYDROLOGY…IAA

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