November 24, 2013 Forecast Discuaaion

000
FXUS61 KALY 241503
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1003 AM EST SUN NOV 24 2013

.SYNOPSIS…
ARCTIC HIGH PRESSURE WILL BUILD EAST FROM THE GREAT PLAINS…SLIDING
OFFSHORE MONDAY. AS IT BUILDS IN…STRONG WINDS…VERY COLD
TEMPERATURES WILL AFFECT THE REGION INTO MONDAY. SCATTERED SNOW
SHOWERS WILL DIMINISH THIS AFTERNOON AND TONIGHT. LATE MONDAY A
WARM FRONT WILL PUSH THROUGH THE REGION. TUESDAY A STORM WILL
MOVE UP THE EASTERN SEABOARD…REACHING NEW JERSEY WEDNESDAY
MORNING. IN ITS WAKE COLD WEATHER WILL RETURN FOR THE THANKSGIVING
HOLIDAY AND WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/…
AS OF 1000 AM EST…MADE SOME MINOR CHANGES FOR THE REST OF THE
DAY…MAINLY TO TEMP/SKY GRIDS TO REPRESENT CURRENT TRENDS.
RADARS SHOWING ANY APPRECIABLE LAKE EFFECT SNOW BANDS WEST OF OUR
AREA CLOSER TO BGM…SO WILL ONLY MENTION CHANCE POPS FOR AN AREA
FROM SOUTHERN HERKIMER SOUTHWARD THROUGH SCHOHARIE…WESTERN
GREENE/ULSTER TO ACCOUNT FOR ANY NARROW AND MINOR FRAGMENTED LAKE
BANDS THAT MAY MOVE BACK ACROSS THE AREA THIS AFTERNOON INTO
EVENING. THE FLOW TRAJECTORY WILL BACK TO MORE OF A 305-310
DIRECTION. GENERALLY LESS THAN AN INCH OF ADDITIONAL ACCUMULATION
IS EXPECTED IN THESE SPOTS…WITH ISOLATED AMOUNTS UP TO 2 INCHES
POSSIBLE. HOWEVER…MOST OF THE AREA WILL NOT SEE ANY MEASURABLE
SNOW TODAY AND TONIGHT.

THE WIND ADVISORY REMAINS IN EFFECT FOR ALL AREAS. GUSTS SHOULD
START TO STEADILY INCREASE TOWARD AFTERNOON ONCE DEEPER MIXING
COMMENCES.

TODAY WOULD BE A COLD DAY (BELOW NORMAL)…EVEN IF WAS THE MIDDLE OF
JANUARY. BUT FOR THE END OF NOVEMBER…HIGHS TODAY WILL AVERAGE 15
TO 20 DEGREES BELOW NORMAL AND HAVE FORECAST HIGHS IN THE TEENS AND
20S. IN ADDITION…THE STRONG GUSTY WINDS WILL MAKE IT FEEL MUCH
COLDER.

WINDS WILL BE DECREASING AND WILL LIKELY DROP OFF TO 10 MPH OR
LESS BY LATE TONIGHT. THUS…DESPITE LOW TEMPS RANGING FROM A
LITTLE BELOW ZERO OVER THE ADIRONDACKS TO 10 TO 12 DEGREES ACROSS
THE HUDSON VALLEY FROM ALBANY SOUTH…WIND CHILL VALUES REMAIN
ABOVE THE THRESHOLD NEEDED FOR WIND CHILL ADVISORIES.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/…
THE GFS OPERATIONAL RUN CONTINUES TO BE THE OUTLIER IN THIS PERIOD
WITH THE COASTAL STORMS EVOLUTION…

PERIOD STARTS WITH SFC HIGH OVER EASTERN SEABOARD…RIDGING NE INTO
NY/NEW ENG. HIGH SLIDES OFFSHORE AND NW-SE WMFNT PUSHES ACROSS RGN
WITH SOME OVERRUNNING MID AND HI CLOUDS…PARTICULARLY N. SCT
-SHSN AS POSSIBLE W/WMFNT BUT ANY LK EFFECT WILL BE ON 240 VECTOR
UP ST. LAWRENCE VLY. MONDAY NIGHT A WK CDFNT PUSHES TO ST LAWRENCE
VLY…AND IS ABSORBED INTO DEVELOPING COASTAL STORM SYSTEM. TEMPS
WILL REMAIN BLO NORMALS AFTER A FRIGID START MONDAY HIGHS WILL
REACH THE MID 20S TO MID 30S.

GEM/NAM/ECMWF/HPC ALL IN AGREEMENT WITH EVOLVING COASTAL STORM.
BULK OF GEFS ENSEMBLE MEMBERS ALSO IN AGREEMENT WITH REST OF MODEL
SUITE. 70% OF GEFS ENSEMBLE MEMBERS HAVE QPF NORTH OF 1.0 IN LIQ
EQUIV…0.1 TO 0.3 OF INITIAL QPF SNOW/MIXED THAN OVER TO A MOSTLY
RAIN EVENT. TWO MEMBERS PRODUCE CONSIDERABLE ICE. OPERATIONAL GFS
REMAINS OUT TO THE SOUTH AND EAST BUT CLOSER TO THE COAST THAN PVS
RUNS. ITS AN OUTLIER IN ITS OWN ENSEMBLE AND WILL NOT BE USED.

CONFIDENCE HAS INCREASED SIGNIFICANTLY IN THE FORECAST. THE MAJORITY
OF THE MODEL SUITE PHASES THE NORTHERN AND SOUTHERN 500HPA STREAMS
AS DIGGING TROF OVER UPR GRTLKS AND CUTOFF LIFTING ENE FM TX PHASE
INTO A FULL LATITUDE TROF FM GRTLKS TO E GULF COAST. TYPE A MILLER
CYCLOGENISUS EVOLVES WITH SFC LOW ORGANIZING ON GULF COAST…AND
MOVING UP AN I-95 CORRIDOR OR EVEN WEST TO NR POU WED AFTN.

PTYPE SHOULD BEGIN AS SNOW OR A MIX…AND TRANSITION QUICKLY TO
MAINLY RAIN. 1000-500DM THICKNESS VALUES REACH 560 ON GEM/ECMWF…850
TEMPS RISE TO +6 TO +10C ON GEM/ECMWF. WITH FULL LATITUDE TROF TO
THE WEST..AND COASTAL LOW…RAIN WILL CONTINUE MUCH OF
WED…AFTER SYSTEM MOVES NE OF RGN…CAA WILL END EVENT IN -SNSH
IN E PRTNS OF FCA…WHICH WILL GET DRY SLOT. FURTHER W 500HPA TROF
AXIS REMAINS W OF FCA…LK ENHANCEMENT AND COLD CONVEYOR BELT
WILL CHANGE PCPN TO SN- AND ALONG WITH UPSLOPE FLOW COULD RESULT
IN A COUPLE OF INCHES N & W ZONES AS -SN CONTINUES WED NT.

TEMPS WILL BE NON DIURNAL AFTER TUESDAY…AND SINCE THE GMOS IS THE
OUTLIER…AND NOT USABLE…WILL POPULATE WITH NAM AND BLEND WHAT
GRIDS I CAN FM GEM AND ECMWF. TEMPS TUESDAY WILL RISE INTO 30S TO
LOW 40S…HOLD STEADY OVERNIGHT. IF FCA GETS INTO WM SECTOR THE
COULD SPIKE WE INTO THE 50S…OTHERWISE 40S…BFE CD ADVECTION
BEGINS LATE WED AND TEMPS PLUNGE ON INCRG NW WINDS AND CAA.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/…
MAJOR COASTAL LOW DEPARTS MARITIMES THANKSGIVING MORNING AS 500
HPA TROF MOVES THROUGH REGION. IN STORMS WAKES VERY STRONG SFC
WIND GRADIENT AND CAA SET UP ACROSS THE REGION. TEMPS WILL START
THANKSGIVING IN SINGLE DIGITS AND TEENS…AND ONLY RECOVER TOT HE
TEENS AND 20S. WINDS WILL BE STRONG. COLD CONVEYOR BELT SNOW
SUPPORTED BY DCVA WILL LINGER INTO THE MRNG…WITH TRRN ENHANCEMENT
N NYS. ONCE 500 HPA TROF DEPARTS A COLD BUT TRANQUIL REGIME WILL
SET UP AS HIGH PRESSURE BUILDS ALONG E COAST INTO FRI. ANOTHER
STRONG JET STREAK MOVES ACROSS NE STATES FRI NT…AND IS FOLLOWED
BY BACKDOOR ARCTIC CDFNT. LARGE ARCTIC HIGH BUILDS SE INTO RGN FM
ONT/QB FOR THE WEEKEND…WITH FAIR BUT WELL BLO NORMAL TEMPS FOR
RES OF EFP. WITH SFC FLOW N TO EAST…LK EFFECT RESPONSE WILL BE
ON WEST END OF LKS…OUT OF OUR FCA.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/…
EXCEPT FOR SOME OCCASIONAL MVFR CIGS AT THE KALB AND KPSF TAF
SITES THROUGH MID MORNING…EXPECT VFR CONDITIONS AT THE
KALB/KGFL/KPOU/KPSF TAF SITES THROUGH THE TAF PERIOD ENDING
12Z MONDAY. AFTER SUNSET EXPECT MAINLY P6SM SKC CONDITIONS.

THE MAIN AVIATION WEATHER PROBLEM FOR TODAY INTO THIS EVENING WILL
BE STRONG NORTHWEST WINDS GUSTING UP TO 30 TO 40 KTS TODAY…WITH
THE STRONGEST WINDS AT KALB AND KPSF. AFTER SUNSET TODAY THE WINDS
WILL BEGIN TO SLOWLY SUBSIDE…BUT GUSTS OF 15 TO 20 KTS WILL
CONTINUE UNTIL AFTER MIDNIGHT. TOWARD SUNRISE ON MONDAY THE WIND S
WILL DECREASE TO 10 MPH OR LESS.

OUTLOOK…
MONDAY THROUGH MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: LOW OPERATIONAL IMPACT. CHANCE OF RA.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY RA…SN…IP.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. LIKELY RA.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA…SHSN.
THANKSGIVING DAY: LOW OPERATIONAL IMPACT. BREEZY. NO SIG WX.

&&

.HYDROLOGY…
SNOW SHOWERS WILL DIMINISH THROUGH THE DAY…WITH DRY CONDITIONS
TONIGHT INTO TUESDAY. THE FRIGID AIR MASS OVER REGION WILL ALLOW
ICE TO BEGIN TO FORM ON SHALLOWER LAKES AND RIVERS SUNDAY INTO
EARLY NEXT WEEK.

TUESDAY AFTERNOON INTO WEDNESDAY A COASTAL STORM COULD BRING 1.5 TO
2.5 INCHES OF LIQUID EQUIVALENT PRECIPITATION TO THE REGION. IT
WILL BEGIN AS SNOW AND COULD LINGER AS SNOW IN THE NORTHERN
MOUNTAINS…HOWEVER IN MUCH OF THE REGION IT IS EXPECTED TO CHANGE
TO RAIN…RESULTING IN SIGNIFICANT WITHIN BANK RISES. IN THIS
STORMS WAKE IT WILL TURN SHARPLY COLDER AGAIN WEDNESDAY
NIGHT…WITH ICE FORMATION LIKELY TO BEGIN ANEW.

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…WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR CTZ001-013.
NY…WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA…WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ001-025.
VT…WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VTZ013>015.

&&

$$
SYNOPSIS…SNYDER
NEAR TERM…GJM/JPV
SHORT TERM…SNYDER
LONG TERM…SNYDER
AVIATION…GJM
HYDROLOGY…SNYDER

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