February 3, 2014 Forecast Discussion

000
FXUS61 KALY 040003
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
703 PM EST MON FEB 3 2014

.SYNOPSIS…
WEAK HIGH PRESSURE WILL BUILD INTO THE REGION FOR LATER
TONIGHT INTO TUESDAY…WITH FAIR CONDITIONS…ALONG WITH GRADUALLY
CLEARING SKIES. A STORM TRACKING JUST TO OUR SOUTH WILL BRING A
WIDESPREAD SNOWFALL TO THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY.
HIGH PRESSURE WITH GENERALLY FAIR BUT COLD WEATHER WILL BUILD IN FOR
THE REST OF THE WORK WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/…
…WINTER STORM WATCH CONTINUES FOR TUESDAY NIGHT AND WEDNESDAY…

AS OF 7 PM EST…SKIES AROUND MOST OF THE REGION REMAIN MOSTLY
CLOUDY…WITH EVEN SOME SPOTTY LIGHT SNOW FLURRIES/SNOW GRAINS
OCCURRING ACROSS PORTIONS OF THE WESTERN ADIRONDACKS.

WE HAVE SIGNIFICANT CONCERNS…BASED ON RECENT SATELLITE
OBS…THAT THE PREVIOUSLY INDICATED CLEARING MAY NOT OCCUR UNTIL
LATER TONIGHT…OR EVEN IN SOME AREAS UNTIL TUE MORNING…AS
ABUNDANT LOW LEVEL MOISTURE REMAINS TRAPPED BENEATH A
STRENGTHENING SUBSIDENCE INVERSION IN THE WAKE OF THE UPPER LEVEL
SHORTWAVE SUPPORTING THE OFFSHORE STORM SYSTEM. MIXING IS WEAK AT
BEST IN THE LOW LEVEL OF THE ATMOSPHERE…SO DOWNSLOPING IS
MINIMAL. AT THIS TIME…HAVE BACKED OFF ON TIMING OF ANY CLEARING
IN MOST AREAS UNTIL AFTER MIDNIGHT…BUT A SUBSEQUENT UPDATE MAY
NEED TO BACK THIS OFF MUCH FURTHER.

WITH CLOUDS PERSISTING LONGER…THE POTENTIAL FOR FORECAST MIN
TEMPS TO BE REACHED IS DECREASING. FOR NOW…HAVE SLOWED DOWN TEMP
FALLS THROUGH MIDNIGHT…BUT KEPT OVERALL MIN TEMPS ASSUMING SOME
CLEARING DEVELOPS LATE. HOWEVER…AGAIN…WITH SUBSEQUENT
UPDATE…IF CLOUDS LOOK LIKE THEY ARE HOLDING TIGHT…MAY HAVE TO
BOOST OVERNIGHT MIN TEMPS BY 5 OR MORE DEGREES ACROSS THE ENTIRE AREA.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/…
…WINTER STORM WATCH CONTINUES FOR TUESDAY NIGHT AND WEDNESDAY…

HIGH PRESSURE BUILDS EAST AND OFFSHORE THROUGH THE DAY BUT MID AND
HIGH CLOUDS SHOULD STREAM INTO THE REGION AHEAD OF THE NEXT
SYSTEM. LIGHT WINDS AND DECREASING SUNSHINE COULD LIMIT THE
WARMING. SO..HIGHS TUESDAY IN THE LOWER TO MID 30S…MID TO UPPER
20S NORTHERN AREAS.

SNOW SPREADS ACROSS THE REGION TUESDAY NIGHT…BUT SOME COOLING
POSSIBLE TUESDAY EVENING DEPENDING ON THE TIMING OF THE
THICKENING OF THE CLOUDS. LOWS SHOULD OCCUR IN THE EVENING…THEN
HOLD STEADY OR RISE A DEGREE OR TWO THROUGH THE REST OF THE NIGHT.
LOWS TUESDAY NIGHT IN THE LOWER 20S…TEENS IN NORTHERN AREAS.

STILL A GOOD CONSENSUS FROM GUIDANCE AND ENSEMBLES FOR A MOSTLY
SNOW EVENT FOR THE ENTIRE FORECAST AREA. THERE STILL COULD BE A
MIX WITH SLEET DURING THE DAY WEDNESDAY FROM KPOU INTO NW CT…BUT
ONLY A CHANCE…AND IT SHOULD NOT COMPROMISE SNOWFALL TOTALS MUCH
IF ANY FOR THOSE AREAS.

THE USUAL DYNAMICS…LOW LEVEL JET CORE…ISENTROPIC LIFT AND
FRONTOGENESIS FORCING MECHANISMS COME TOGETHER OVER OUR REGION…
ASSOCIATED WITH UPPER ENERGY EJECTING FROM THE SOUTH CENTRAL U.S.
THERE SHOULD BE ENOUGH MOISTURE FOR A WIDESPREAD 7 INCHES OF SNOW
OR BETTER…BUT THE LOCAL TERRAIN EFFECTS AND ANY DOWNSLOPING AND
VALLEY SHADOWING DETAILS WILL BE CLEARER AS WE GET NEARER TO THE
EVENT. SOME AREAS WILL SEE CLOSER TO 6 OR 7 INCHES…OTHER
AREAS…ESPECIALLY HIGHER TERRAIN…COULD SEE OVER A FOOT OF
SNOW…AGAIN DEPENDING ON WHAT AREAS SEE DOWNSLOPING OR VALLEY
SHADOWING THAT COULD LIMIT THE SNOWFALL IN SOME AREAS.

BASED ON THERMAL PROFILES IN THE GUIDANCE…LIQUID TO SNOWFALL
RATIONS LOOK TO BE NEAR CLIMATOLOGY…10 TO 1 OR 12 TO 1…WHICH
WOULD RESULT IN A BIT HEAVIER SNOW THAN THE DRY FLUFFY SNOWS
EARLIER IN THE WINTER. HIGHS WEDNESDAY LOOK TO BE IN THE 20S TO
LOWER 30S. THE SNOW WILL IMPACT THE WEDNESDAY MORNING
COMMUTE…AND DEPENDING ON HOW LONG SNOW LINGERS…MAYBE AS
HUDSON/MOHAWK CONVERGENCE…THERE COULD BE AN EXTENSION INTO THE
WEDNESDAY EVENING COMMUTE.

SNOW SHOULD DEPART WEDNESDAY EVENING…WITH GRADUAL CLEARING
THROUGH THE REST OF THE NIGHT. LOWS WEDNESDAY NIGHT IN THE
TEENS…PERHAPS NEAR ZERO SOUTHERN ADIRONDACKS. THERE COULD BE
SOME LAKE EFFECT SNOW ACTIVITY INTO THE WESTERN MOHAWK
VALLEY…SCHOHARIE VALLEY AND EASTERN CATSKILLS….THAT COULD
EXTEND INTO THURSDAY. HIGHS THURSDAY IN THE 20S…TEENS IN
NORTHERN AREAS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/…
THE PERIOD STARTS OFF LARGELY DRY WITH A GOOD MIX OF SUN AND CLOUDS
UNDER THE INFLUENCE OF HIGH PRESSURE…WHICH ON FRIDAY EXTENDS FROM
THE NORTHERN ROCKIES AND PLAINS ACROSS THE MIDWESTERN CORN BELT TO
THE MID-ATLANTIC REGION. THEN WE SEGUE INTO A WINTER STORM FOR THE
WEEKEND…THEN BACK TO A DRIER REGIME WITH INCREASING SUNSHINE
THROUGH MONDAY.

LOW PRESSURE DEVELOPING OVER THE GULF COAST REGION WILL TRACK UP THE
LEE OF THE SOUTHERN APPALACHIANS SATURDAY NIGHT CONTINUING ON UP OFF
THE DELMARVA COAST THROUGH SUNDAY…AND OUT OVER THE NORTH ATLANTIC
SOUTH OF NOVA SCOTIA INTO MONDAY. WHILE IT WOULD SEEM THE MAIN LOW
WOULD APPEAR TO BE HELD SOUTH ENOUGH TO STAVE OFF HIGHER SNOW AMOUNTS
FOR OUR FORECAST AREA…A SURFACE TROF ORIENTED FROM THE SOUTHERN
APPALACHIANS TO THE EASTERN GREAT LAKES ON SUNDAY COULD BE A FLY IN
THE OINTMENT. WITH THE GFS AND ECMWF OFF FROM ONE ANOTHER ON START
TIMING BY A GOOD 6 TO 12 HOURS…CONFIDENCE IS STILL ON THE LOW SIDE
FOR THIS SYSTEM…AND WE HAVE NO MORE THAN CHC POPS ATTM. BOTH
MODELS ARE VERY CLOSE IN PROVIDING US SUFFICIENTLY LESS SNOW THAN
WHAT IS FORECAST FOR WEDNESDAY.

DAY-TO-DAY HIGH TEMPERATURES WILL BE FAIRLY CONSISTENT DURING THIS
PERIOD…AND WILL BE SEVERAL DEGREES BELOW NORMAL. THE HIGHS WILL
RANGE FROM MAINLY THE UPPER 20S TO AROUND 30 DEGREES. LOWS WILL
SHOW MORE OF A TENDENCY TOWARD MODERATION…WITH READINGS STARTING
OUT IN THE MINUS 5 TO MID SINGLE DIGITS ABOVE ZERO RANGE THURSDAY
NIGHT. BY SATURDAY AND SUNDAY NIGHTS…THE LOWS WILL RANGE FROM
AROUND ZERO IN THE WESTERN ADIRONDACKS…TO THE MID TEENS IN THE MID
HUDSON VALLEY…STILL A FEW DEGREES BELOW NORMAL.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/…
CLOUDS…WITH CIGS RANGING ON THE FRINGE OF VFR/MVFR…CONTINUE
ACROSS THE TAF SITES…WITH MVFR MORE PREVALENT AT KPSF AND
OCCASIONALLY AT KALB. WE DO EXPECT THE CIGS TO GRADUALLY BECOME
MAINLY VFR LATER TONIGHT…WITH SOME CLEARING POSSIBLE. IF SKIES
CAN CLEAR AT KPOU…SOME FOG AND MVFR/IFR VSBYS MAY DEVELOP AFTER
MIDNIGHT DUE TO THE MOIST BOUNDARY LAYER WITH THE ADDED WET
SNOWPACK…AND LIGHT TO CALM WIND. HOWEVER…SHOULD THE CLOUDS
PERSIST…THIS POTENTIAL WILL BE MUCH LESS.

MAINLY VFR CONDITIONS WILL THEN PREVAIL FOR TUESDAY.

WINDS WILL REMAIN LIGHT…FROM THE NORTH TO NORTHEAST AT LESS THAN
5 KT…AND BACK SLIGHTLY OVERNIGHT. ON TUESDAY…A LIGHT NW TO W
WIND AT 5-10 KT IS EXPECTED…ALTHOUGH MAY REMAIN LIGHT/VARIABLE
AT KPOU/KGFL.

OUTLOOK…
TUESDAY NIGHT TO WEDNESDAY: HIGH OPERATIONAL IMPACT. DEFINITE SN.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.

&&

.HYDROLOGY…
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT FIVE DAYS.

OUR REGION WILL HAVE A SNOWSTORM LATE TUESDAY NIGHT THROUGH
WEDNESDAY.

DRY AND COLD WEATHER RETURNS BY THURSDAY.

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…WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY
AFTERNOON FOR CTZ001-013.
NY…WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY
AFTERNOON FOR NYZ032-033-038>043-047>054-058>061-063>066-
082>084.
MA…WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY
AFTERNOON FOR MAZ001-025.
VT…WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY
AFTERNOON FOR VTZ013>015.

&&

$$
SYNOPSIS…KL/NAS
NEAR TERM…KL/NAS
SHORT TERM…NAS
LONG TERM…ELH
AVIATION…KL/WASULA
HYDROLOGY…GJM/NAS

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