Forecast Discussion: November 6, 2014

000
FXUS61 KALY 061416
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
916 AM EST THU NOV 6 2014

.SYNOPSIS…
AN AREA OF LOW PRESSURE WILL DEVELOP AND MOVE UP THE NORTHEAST COAST
THROUGH TONIGHT…ALLOWING FOR RAIN…WHICH WILL CHANGE TO SNOW OVER
THE HIGHER ELEVATIONS TONIGHT. IN THE STORMS WAKE…MUCH COLDER AIR
WILL POUR INTO THE REGION FRIDAY WITH BRISK WINDS AND A FEW
LINGERING MOUNTAIN SNOW SHOWERS. COOLER AIR WILL BE IN PLACE OVER
THE REGION…WITH ANOTHER FRONTAL BOUNDARY BRINGING SOME MORE RAIN
AND SNOW SHOWERS TO THE AREA ON SATURDAY NIGHT INTO SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/…
AS OF 916 AM EST…IT WILL BE AN UNSETTLED AND GLOOMY TODAY AS A
DOUBLE-BARREL LOW PRESSURE SYSTEM BRINGS A SOAKING RAIN TO THE
REGION. SKIES ARE ALREADY CLOUDY ACROSS THE ENTIRE AREA…AND
REGIONAL MOSAIC RADAR SHOWS SOME RETURNS ACROSS SOUTHERN PARTS OF
THE AREA. INITIALLY…THE GREATEST THREAT FOR RAIN WILL BE SOUTH
OF THE CAPITAL REGION AS WARM CONVEYOR BELT ISENTROPIC LIFT ALONG
THE BAROCLINIC ZONE ACTS AS THE PRIMARY DYNAMIC FORCING THROUGH
THE MORNING HOURS. HAVE INDICATED CHANCE POPS ACROSS THE ENTIRE
FORECAST AREA DURING THE MORNING HOURS…WITH LIKELY POPS SOUTH OF
THE CAPITAL REGION.

BY THE EARLY AFTERNOON…THE UPSTREAM SHORTWAVE ACROSS THE GREAT
LAKES WILL BE CLOSER TO THE REGION…ALONG WITH A MORE AMPLIFIED
NEUTRAL TO SLIGHTLY NEGATIVELY-TILTED UPPER-LEVEL TROUGH. WITH THE
SLIGHTLY NEGATIVE TILT OF THE UPPER-LEVEL TROUGH AXIS AND A POTENT
NORTHERN STREAM POTENTIAL VORTICITY ANOMALY ROUNDING THE BASE OF THE
TROUGH…A TRANSFER OF ENERGY WILL OCCUR ALLOWING FOR ENHANCED
CYCLOGENESIS ALONG THE BAROCLINIC ZONE. THIS WILL ALLOW FOR A PERIOD
OF ENHANCED DYNAMIC LIFT ACROSS THE REGION…AS ISENTROPIC LIFT
ALONG THE WARM AND COLD CONVEYOR BELTS INTERACTS WITH PLENTIFUL
CYCLONIC VORTICITY ADVECTION UNDERNEATH THE LEFT-EXIT REGION OF A
120 KT UPPER-LEVEL JET STREAK AND BRINGS A STEADY RAIN DURING THE
AFTERNOON AND EARLY EVENING HOURS.

HIGH TEMPERATURES WILL STRUGGLE WITH THE ABUNDANT CLOUD COVER ACROSS
THE REGION…WITH HIGHS EXPECTED TO BE LARGELY IN THE MID TO UPPER
40S. TEMPERATURES MAY REACH INTO THE LOW 50S ACROSS THE HUDSON
VALLEY AND VALLEY LOCATIONS IN THE SOUTHERN GREENS AND BERKSHIRES
THAT ARE AIDED BY LOCAL DOWNSLOPING FLOWS.

FOR TONIGHT…THE DEVELOPING COASTAL LOW WILL BE EXITING OFF TO THE
NORTHEAST AS IT MOVES UP THE I-95 CORRIDOR. THE FORECAST
AREA…ESPECIALLY POINTS NORTH AND WEST OF THE CAPITAL REGION WILL
STILL BE UNDER THE INFLUENCE OF THE COLD CONVEYOR BELT AND
UPPER-LEVEL TROUGH WHICH WILL HELP TO FOCUS LINGERING RAIN/SNOW
SHOWERS. AS TEMPERATURES DROP DURING THE NIGHTTIME HOURS…HIGHER
TERRAIN LOCATIONS PRIMARILY ACROSS THE SOUTHERN ADIRONDACKS AND
SOUTHERN GREENS IN SOUTHERN VERMONT WILL SEE A TRANSITION TO ALL
SNOW…WITH ACCUMULATIONS OF 1-4 INCHES POSSIBLE. A DUSTING WILL
BE POSSIBLE IN NEARBY HILLTOWNS. WHILE THIS SNOW IS EXPECTED TO
REMAIN BELOW ADVISORY CRITERIA…WILL MENTION IN HWO.

LOW TEMPERATURES THURSDAY NIGHT LOOK TO SETTLE IN THE MID 30S FOR
MUCH OF THE REGION…EXCEPT FOR UPPER 20S TO LOW 30S ACROSS HIGHER
TERRAIN LOCATIONS NORTH OF THE CAPITAL REGION.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/…
MDL SUITE (GFS/GEM/NAM/ECMWF) REMAINS IN AGREEMENT AS 500HPA AND
STRENGTHENING COASTAL STORM IN GULF OF MAINE SLOWLY LIFT NE. IN
THEIR WAKE A 16 HPA N WIND GRADIENT PERSISTS OVR FCA…AS
ADDITIONAL SHORT WAVES DIG INTO 500HPA TROF. THAT ALONG WITH LK
EFFECT RESPONSE OVER CNTRL AND W NYS…AND NW HIR ELEVATION
FORCING WILL (AS PER CSTAR I/II) WILL KEEP -SN OR -SHSN OVER HIR
TRRN PARTICULARLY NW OF ALB. ADD IN CAA…TEMPS IN 30S AND
40S…AND BRISK WINDS IT WILL FEEL ALMOST LIKE WINTER.

FRI EVNG TROF AXIS MVS EAST OF FCA…AND WIND GRADIENT SUBSIDES
AS SFC HIGH PRESSURE RIDGE AXIS FM TN VLY TO E GRTLKS SHIFTS E. BY
DAYBREAK THIS RIDGE IS ALONG THE E SEABOARD AS FAST NW-W 500HPA
REPLACES CUT OFF OVER E USA. AFTER FAIR CONDS LATE FRI NT AND SAT
MRNG…NXT 500 SHORT WV COMES FLYING EAST WITH ITS SFC CDFNT.
CLOUDS FM THIS SYSTEM MOVE IN MIDDAY AND AFTN SAT WITH -SHRA
(-SHSN HIR ELEVATIONS N) SAT NT ACCOMP CFP. IT DEPARTS BY DAYBREAK
AND ANOTHER SFC RIDGE BUILDS N INTO REGION WITH FAIR CONDS. YET
ANOTHER 500HPA SHORT WV COMES FLYING DOWN THE NOW W 500HPA FLOW
IN A MOISTURE STARVED ENVIRONMENT SUN. THIS ONE IS ASSOC WITH A WK
FRONTAL SYSTEM PASSING WELL N OF FCA…AND ITS CLOUDS APPEAR TO BE
WAA RELATED AS THEY INCR SUN AND SUN NT.

TEMPS DURING THIS PERIOD WILL BE NR NORMAL MINS…AND BLO NORMAL
MAXES.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/…
GEM/ECMWF AND GFS ALL EVOLVE DIFFERENT SOLUTIONS DURING THIS
PERIOD WITH THE GFS BEING THE MID POINT. FAST ZONAL FLOW AT
500HPA BREAKS DOWN AS LARGE CUTOFF EVOLVES OVER ONTARIO/UPR GRT
PLAINS.

GEM TURNS 500HPA FLOW SW WITH BUILDING A RIDGE ALONG THE E
SEABOARD…SETTING UP A RAPID RETURN TO ABV NORMAL TEMPS WITH INCRG
SW FLOW AND FAIR CONDS.

THE GFS HAS THE LARGE CUT OFF LOW OSCILLATE ABOUT ONTARIO PROVINCE
WITH A FLATTER RIDGE WITH SOME CLOUDS AND ISOLD -SHRA ALONG N
TIER EARLY MON…BUT STILL A RETURN TO MILD AND MAINLY FAIR CONDS. IT
BRINGS A CDFNT ACROSS FCA AS A SERIES OF SHORT WVS SHARPEN A TROF
TO ITS SOUTH TUES NT.

ALL MEMBERS OF THE 00UTC GEFS ENSEMBLE ARE DRY MON INTO LATE TUES
OR TUES EVNG BUT ONE.

MEANWHILE THE 00UTC ECMWF IS CLEARLY AN OUTLIER ATTM EJECTING
THIS CUTOFF EAST FM ONT TO QB MUCH EARLIER ON MON….AND IN SO
DOING PUSHES A CDFNT S THROUGH THE REGION AS ARCTIC HIGH BUILDS
ACROSS S CANADA…CAA POURS SOUTH…THEN OVERRUNNING SETS UP N OF
THIS FRONT TUES NT INTO WED.

HPCS CURRENT GUID AND CURRENT FCST REFLECT A SOLTN CLOSE TO GFS AND
FCST WILL CONTINUE TO REFLECT THIS THINKING SO WILL POPULATE WITH
HPC. IF THE SOLUTION LEANS CLOSER TO GEM…TUES AND EVEN WED COULD
BE WELL ABV NORMAL. IF THE ECMWF IS CORRECT ONE COULD BE
SHOVELING SNOW BY WED. NEEDLESS TO SAY ITS NOT A HIGH CONFIDENCE
FCST AT THIS POINT…AND MAYBE EVEN LOWER CONF THAN YESTERDAY
GIVEN THE OOUTC ECMWF.

WITH HPC GUID TEMPS SHOULD BE SLIGHTLY BLOW NORMS MON…RETURN TO
ABV NORMS TUE.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/…
VFR FLYING CONDITIONS WILL PREVAIL EARLY THIS MORNING BEFORE
GRADUALLY DETERIORATING TO MVFR AFTER 15Z AS RAIN ASSOCIATED WITH
A LOW PRESSURE SYSTEM OVERSPREADS THE REGION.

SHOWERS ASSOCIATED WITH A DOUBLE-BARREL LOW PRESSURE SYSTEM WILL
OVERSPREAD THE TAF SITES PRIMARILY AFTER 18Z…EXCEPT AT KPOU
WHERE THE SHOWERS MAY START AS EARLY AS 15Z. HAVE MENTIONED VCSH
AT KPOU STARTING AT 12Z AND 15Z AT KALB AND KPSF TO ACCOUNT FOR
ANY WIDELY SCATTERED SHOWERS AHEAD OF THE MAIN RAIN SHIELD.
VISIBILITIES AND CEILINGS WILL DETERIORATE TO MVFR AFTER 18Z AS
STEADIER RAIN MOVES INTO THE REGION. WINDS WILL BE OUT OF THE
NORTHEAST AT KGFL AND KALB AROUND 5 KNOTS AND LIGHT AND VARIABLE
AT KPSF AND KPOU.

MVFR FLYING CONDITIONS ARE EXPECTED TO CONTINUE INTO THURSDAY
NIGHT AS RAIN CONTINUES TO IMPACT THE REGION. WILL HAVE TO MONITOR
TRENDS AFTER 00Z…AS CEILINGS MAY INTERMITTENTLY LOWER TO IFR
ESPECIALLY AT KGFL AND KPSF.

OUTLOOK…

FRIDAY-FRIDAY NIGHT: ISOLATED SHRA/SHSN.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SUNDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY NIGHT TO VETERANS DAY:NO OPERATIONAL IMPACT. NO SIG WX.

&&

.FIRE WEATHER…
NO FIRE WEATHER RELATED CONCERNS ARE ANTICIPATED…AS A WIDESPREAD
RAIN IS EXPECTED TODAY INTO TONIGHT ACROSS THE REGION.

LOW PRESSURE WILL ORGANIZE NEAR NEW JERSEY TODAY AND INTENSIFY AS
IT MOVES UP THE SEABOARD TO NOVA SCOTIA FRIDAY. IT WILL BRING
WIDESPREAD RAIN TO THE AREA WITH THE RAIN CHANGING TO SNOW ACROSS
THE HIGHER ELEVATIONS EARLY FRIDAY. IN THE STORMS WAKE MUCH
COLDER AIR WILL POUR INTO THE REGION FRIDAY WITH BRISK WINDS AND
ELEVATION SNOW SHOWERS. THE WEEKEND WILL BRING A FAST MOVING
PARADE OF WEATHER SYSTEMS.

&&

.HYDROLOGY…
NO WIDESPREAD HYDROLOGIC PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.

MOST OF THE REGION WILL HAVE 0.30 TO 0.80 QPF IN WIDESPREAD RAIN
THIS AFTERNOON INTO TONIGHT. RAIN WILL TAPER OFF TO SHOWERS…WITH
SNOW SHOWERS OVER HIGHER TERRAIN OVERNIGHT. THIS WILL RESULT IN
SOME MINOR RISES ALONG RIVERS AND STREAMS INTO FRIDAY NIGHT.

RAIN AND SNOW SHOWERS WILL LINGER INTO FRIDAY MAINLY NORTH AND
WEST OF ALBANY. THEN MOSTLY DRY CONDITIONS WILL BE THE RULE FRIDAY
NIGHT INTO TUESDAY OTHER THAN SOME LIGHT RAIN OR SNOW SHOWERS WITH
A FAST MOVING FRONTAL SYSTEM SATURDAY NIGHT.

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…FRUGIS/SNYDER
NEAR TERM…FRUGIS/IRL
SHORT TERM…SNYDER
LONG TERM…SNYDER
AVIATION…IRL
FIRE WEATHER…SNYDER
HYDROLOGY…SNYDER

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