Event Forecast Discussion

000
FXUS61 KALY 030111
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
810 PM EST SAT FEB 2 2013

.SYNOPSIS…
A CLIPPER LOW WILL MOVE ACROSS THE REGION WITH ISOLATED
TO SCATTERED SNOW SHOWERS THROUGH THIS EVENING. ANOTHER CLIPPER
WILL IMPACT THE REGION LATE SUNDAY INTO SUNDAY NIGHT WITH SOME LIGHT
SNOW AND CONTINUED BELOW NORMAL TEMPERATURES INTO NEXT WEEK. MUCH OF
THE UPCOMING WEEK WILL BE DRY WITH SEASONABLY CHILLY TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/…
AS OF 800 PM…INCREASED SNOWFALL AMOUNTS AND COVERAGE OVER MAINLY
RENSSELAER COUNTY PER RADAR RETURNS INDICATED THAT MODERATE SNOW IS
FALLING IN SPOTS THERE. AGAIN…ALSO ISSUED A SPECIAL WEATHER
STATEMENT REFLECTING THE SHORT TERM CONCERNS.

AS OF 730 PM EST…INTERESTING FEATURES OVER OUR REGION. LIGHT SNOW
ACROSS THE MID HUDSON VALLEY VERY DBZ VALUES BARELY AT 10 DBZ! RADAR
INDICATED ANOTHER CONVERGENCE (OR UPSLOPE) AREA OF LIGHT SNOW
DEVELOPING ON THE EAST SIDE OF THE HUDSON RIVER WITH DBZ VALUES
RAMPING OVER 20 DBZ. SO FAR…NO REPORTS OF SNOW WITH THIS BUT IT IS
LIKELY HAPPENING. WE WILL ISSUE A SPECIAL WEATHER STATEMENT FOR IT.

OUR 00Z ALY RAOB INDICATED OUR SOUNDING IS FAIRLY MOIST WITH A
SOMEWHAT STEEP LOW LEVEL LAPSE RATE…ENOUGH TO PRODUCE AN
ENHANCEMENT OF SNOW SHOWERS.

FOR THIS UPDATE BEEFED UP COVERAGE A LITTLE IN SOUTHERN ZONES…AS
WELL AS THIS FEATURE JUST TO THE EAST OF ALBANY. WE WILL MONITOR THE
SITUATION TO SEE IF THESE BANDS INCREASE.

SYNOPTICALLY…OUR REGION IS COMING UNDERNEATH WEAK ASCENT FROM AN
ADVANCING SHORT WAVE FROM THE OHIO VALLEY. THERE IS ANOTHER SHORT
WAVE FURTHER SOUTH…WHICH WILL MERGE WITH THE NORTHERN ONE TO FORM
AN IMPRESSIVE OCEAN STORM.

THE APPROACHING WEAK SHORT WAVE TROUGH PER THE H2O VAPOR LOOP AND
WEAK SURFACE TROUGH AXIS OVER THE GREAT LAKE STATE WILL MOVE ACROSS
THE REGION THROUGH THE EVENING HOURS.

LAKE EFFECT SNOW DOWNWIND OF LAKE ONTARIO SHOULD REMAIN NORTH OF
HERKIMER COUNTY AS BOUNDARY LAYER WINDS REMAIN BETWEEN 220-240
DEGREES. HOWEVER…WITH THE PASSAGE OF THE WEAK SURFACE
TROUGH…THE FLOW IS EXPECTED TO BRIEFLY BECOME WESTERLY LATE THIS
EVENING. ALTHOUGH…THE INVERSION HEIGHTS ARE EXPECTED TO DROP
INCLUDING THE WIND FIELD THAT MINIMIZE INLAND EXTENT ALONG WITH
DRIER AIR. SO THE CHANCE POPS WILL CONTINUE THROUGH MOST OF THE
NIGHT ACROSS THE NORTHERN HALF OF HERKIMER COUNTY. MOS GUIDANCE
LOOKS GOOD AND ACCEPTED.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/…
A MORE POTENT WAVE SEEN IN THE H2O VAPOR LOOP WAS JUST PASSING BY
EASTERN LAKE WINNIPEG WITH AN ADDITIONAL WAVE CROSSING MINNESOTA.
THESE WAVES WILL ACT IN TANDEM AND STRENGTHEN THE UPPER JET OVER
THE MIDDLE ATLANTIC AND BAROCLINICITY TO SPAWN A DEEPENING SURFACE
LOW OVER THE OPEN WATERS OF THE ATLANTIC. AS THE UPPER FLOW
BECOMES SOMEWHAT NEGATIVELY TILTED…AN EVOLVING INVERTED SURFACE
TROUGH SETS UP ACROSS THE REGION DURING SUNDAY INTO SUNDAY NIGHT.
THE QG FORCING DOES INCREASE A BIT ALONG WITH SUFFICIENT MOISTURE
PROFILES FOR LIGHT SNOW TO DEVELOP ACROSS PORTIONS OF THE REGION.
THE BEST OPPORTUNITIES FOR SNOW WILL ALONG FAVORABLE WEST FACING
UPSLOPE AREAS OF THE DACKS…CATSKILLS…TACONICS…BERKS…SOUTHERN
GREENS AND NORTHERN LITCHFIELD HILLS THROUGH THE AFTERNOON AND
EVENING HOURS. HERE IS WHERE WE WILL PLACE UP TO LIKELY POPS WITH
CHC-SCT POPS ELSEWHERE. EITHER WAY…QPF AMOUNTS REMAIN LIGHT WITH
VALUES RANGING FROM A FEW HUNDREDTHS TO A COUPLE TENTHS ACROSS THE
HIGHER TERRAIN. THIS WOULD EQUATE TO SNOWFALL AMOUNTS OF 1 TO 3
INCHES WHEN USING UP TO A 20:1 RATIO. THE INVERTED TROUGH AXIS
QUICKLY LIFTS FROM SOUTHWEST TO NORTHEAST SUNDAY NIGHT WITH
DIMINISHING SNOWFALL TRENDS. THERE COULD BE A WINDOW OF A MOHAWK
HUDSON CONVERGENCE DURING THE EVENING HOURS AS THE STORM INTENSIFIES
OFF THE NEW ENGLAND COAST. HIGHS WILL RANGE FROM THE 20S TO L30S
ACROSS THE REGION…TO SINGLE DIGITS TO TEENS FOR LOWS.

MONDAY-MONDAY NIGHT…THE WORK WEEK WILL OPEN WITH BLUSTERY AND COLD
CONDITIONS…AS A DEEPENING AND INTENSIFYING LOW PRESSURE SYSTEM
MOVES TOWARD LABRADOR…AND ARCTIC HIGH PRESSURE ATTEMPTS TO BUILD IN
FROM THE GREAT LAKES REGION AND ONTARIO. W/NW WINDS OF 15 TO 25
MPH WILL BE COMMON WITH SOME GUSTS AROUND 30-40 MPH. WESTERLY
UPSLOPE SNOW SHOWERS OVER THE SRN GREENS AND WRN DACKS WILL END
DURING THE AFTERNOON WITH ADDITIONAL LIGHT ACCUMULATIONS. IN THE
COLD ADVECTION REGIME…850 TEMPS FALL TO -17C TO -22C. MAX TEMPS
WILL CONTINUE TO RUN BELOW NORMAL WITH TEENS TO M20S OVER THE
HILLS AND MTNS…AND L20S TO L30S IN THE VALLEY AREAS. TEMPS MAY
FALL DURING THE AFTERNOON. DIMINISHING WINDS AND FRIGID CONDITIONS
ARE ANTICIPATED MON NIGHT WITH HIGH PRESSURE BUILDING IN WITH LOWS
BELOW ZERO OVER THE ADIRONDACK PARK…AND SRN GREENS…SINGLE
DIGITS EVERYWHERE ELSE…EXCEPT 10-15F IN THE MID HUDSON VALLEY
AND SRN LITCHFIELD COUNTY. WE WILL MONITOR THE POTENTIAL FOR LAKE
EFFECT SNOW TO SET UP ONCE AGAIN AS LOCAL CSTAR RESEARCH INDICATES
THE INLAND PENETRATION MIGHT JUST STOP AT THE HERKIMER COUNTY
BORDER. FOR NOW…WE WILL HIGHLIGHT IN THE HWO AND CONTINUE TO
MONITOR TRENDS CLOSELY. THANKS TO THE SURROUNDING OFFICES FOR THE
COLLABORATION TODAY.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/…
MODEL GUIDANCE CONTINUES TO INDICATE THAT THE LONG RANGE PERIOD WILL
START OUT WITH A CONTINUATION OF A BROAD LONGWAVE TROUGH…GRADUALLY
FLATTENING WITH TIME. BY SATURDAY…IT ACTUALLY LOOKS AS IF RIDGING
ALOFT COULD BEGIN A PERIOD OF MODERATION. TEMPERATURES LOOK TO START
OUT BELOW NORMAL…MODERATING TO NORMAL BY LATE IN THE PERIOD.

TUESDAY LOOKS DRY AS HIGH PRESSURE WILL MOVING OVER THE AREA. THEN A
WEAK CLIPPER LOOKS TO TRACK SOUTH OF OUR REGION. THE GFS IS THE IS
THE WEAKEST WITH THIS CLIPPER…BUT THEY ALL GIVE LIGHT QPF AMOUNTS
AT THE MOST…IN THE FORM OF LIGHT SNOW OR SNOW SHOWERS. FOR
NOW…AMOUNTS LOOKS LIGHT ENOUGH TO ONLY GO WITH SLIGHT POPS (20)
TUESDAY NIGHT INTO WEDNESDAY.

ANOTHER HIGH PRESSURE LOOKS TO BUILD INTO THE REGION WEDNESDAY NIGHT
INTO THURSDAY. WE KEPT BOTH THESE PERIODS DRY (POPS LESS THAN 15
PERCENT). IT SHOULD BE NOTED THE CANADIAN MODEL IS QUICK TO BRING
THE NEXT SYSTEM IN FROM THE OHIO VALLEY…SPREADING QPF BY LATE
THURSDAY. FOR NOW…HAVE DISCARDED THIS POSSIBILITY.

BOTH THE GFS AND EUROPEAN MODELS BRING THE NEXT CLIPPER TYPE SYSTEM
INTO THE REGION THURSDAY NIGHT AND FRIDAY. THE EUROPEAN TRACKS THE
SYSTEM FURTHER SOUTH…ALONG ABOUT THE I-84 CORRIDOR. IF THIS WERE
TO BE THE CASE…ACCUMULATING SNOWS ARE POSSIBLE IN MOST PLACES ON
FRIDAY. HOWEVER…THE GFS CONTINUES TO TRACK THE SAME STORM ABOUT
200 MILES FURTHER NORTH…IMPLYING STEADIER SNOW NORTH OF
ALBANY…AND SCATTERED RAIN OR SNOW SHOWERS FROM ALBANY SOUTH.

HAVE LEANED WITH THE EUROPEAN SOLUTION ON THIS ONE SO WILL GO 40
POPS FOR MAINLY SNOW. TO THE SOUTH OF ALBANY…SURFACE TEMPERATURES
LOOK MARGINALLY ENOUGH TO WARM PRECIPITATION TO A MIX OF RAIN AND
SNOW (PROVIDED THE RATES ARE NOT TOO HEAVY). IT IS WAY TOO FAR OUT
TO REALLY DETERMINE HOW HEAVY PRECIPITATION WOULD BE BUT THE
POSSIBILITY IS THERE.

SATURDAY…WHATEVER SYSTEM THAT AFFECTS US SHOULD BE TO OUR EAST
ALLOWING MORE HIGH PRESSURE TO BUILD IN. BY THIS TIME THOUGH…THAT
AIR BEHIND THIS SYSTEM WILL NOT BE ALL THAT COLD (WITH H850 TEMPS IN
THE -5 TO -10C) RANGE…SO SEASONABLY COLD AT WORST.

TEMPERATURES START OFF COLD ON TUESDAY WITH HIGHS MAINLY IN THE 20S
(TEENS NORTH) AND OVERNIGHT LOWS TUE/WED INTO IN THE TEENS (SINGLE
DIGITS NORTH). THEY WILL MODERATE SLOWLY WITH TIME…WITH HIGH 25-30
WED (20-25 NORTH)…AND MAINLY IN THE 30S BY FRIDAY AND SATURDAY
AFTERNOON (SOME UPPER 20S NORTH). OVERNIGHT LOWS WILL TEND TO BE
AROUND 15-20 (5-15 NORTH).

NORMALS FEB 5TH-8TH:
ALBANY: HIGHS LOWER 30S. LOWS MID TEENS.
GLENS FALLS: HIGHS LOWER 30S. LOWS UPPER SINGLE DIGITS.
POUGHKEEPSIE: HIGHS UPPER 30S. LOWS UPPER TEENS.
BENNINGTON: HIGHS LOWER 30S. LOWS MID TEENS.
PITTSFIELD: HIGHS AROUND 30. LOWS MID TEENS.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/…
FORECAST CONFIDENCE FOR THIS ISSUANCE WAS ONLY MODERATE (NOT HIGH).

A WEAK CLIPPER SYSTEM WILL APPROACH FOR THIS EVENING. WHILE THERE IS
LITTLE MOISTURE ASSOCIATED WITH THIS SYSTEM…STEEP LOW LEVEL LAPSE
RATE HAS APPARENTLY ENHANCED SNOW GROWTH FOR AREAS OF LIGHT SNOW TO
DEVELOP.

ONE AREA OF LIGHT SNOW HAS DEVELOPED OVER THE KPOU AREA PRODUCING
MARGINAL IFR AT THIS TIME. WE DO NOT THINK CONDITIONS WILL BE THAT
LOW THAT LONG SO FOR NOW INCLUDED A TEMPO FOR MVFR (3SM) FOR -SN
THROUGH THIS EVENING.

OTHERWISE…RIGHT NOW WE FEEL MOST AREAS WILL NOT BE DIRECTLY
IMPACTED BY SNOW FROM THIS SYSTEM…BUT THREW IN VCSH TO COVER THE
POSSIBILITY THAT SOME SNOW SHOWERS COULD BREAK UP (AS THEY HAD JUST
TO THE NORTHEAST OF THE ALBANY AIRPORT).

SOME MVFR CLOUDS LOOK TO FORM AT KPOU…ESPECIALLY NOW THAT SOME
LIGHT SNOW HAS DEVELOPED. THIS COULD PERSIST INTO EARLY SUNDAY.

WILL CONTINUE TO MONITOR AND YOU SHOULD CONTINUE TO CHECK BACK ON
THIS PRODUCT TO SEE IF ANY UPDATES HAVE ENSUED.

THE WIND HAS BEEN MAINLY FROM THE SOUTH OR SOUTHWEST UNDER 10KTS.
THERE WERE SOME HIGHER GUSTS EARLIER…BUT FROM HERE ON LOOK FOR
WITH THE WINDS TO BE VARIABLE TO SOUTHWEST UNDER 10KTS THROUGH MUCH
OF TOMORROW.

ANOTHER CLIPPER MIGHT BRING SOME MORE NUISANCE SNOW SHOWERS TO THE
TERMINALS TOMORROW. RIGHT NOW…THINKING VFR WILL PREVAIL BUT AGAIN
CONFIDENCE IS ONLY MODERATE.

OUTLOOK…
SUN NIGHT…MAINLY VFR. CHC FOR SUB-VFR WITH CHC FOR LIGHT SNOW. AT
KPSF SNOW LIKELY AFTER MIDNIGHT.
MON-TUE…VFR. NO SIG WX.
TUE NIGHT. MAINLY VFR. CHC -SHSN MAINLY AFTER MIDNIGHT.
WED…MAINLY VFR. CHC -SHSN IN THE AM AND SLIGHT CHC IN THE AFTN.
WED NIGHT-THU…VFR. NO SIG WX.

&&

.HYDROLOGY…
THE NEXT 5 DAYS EXTENDING INTO THE MIDDLE OF NEXT WEEK WILL FEATURE
MINIMAL HYDRO PROBLEMS. A FEW RIVER GAGES ARE STILL SUGGESTING
ICE IMPACTING RIVER READINGS AS WE REMAIN IN CONTACT WITH LOCAL
OFFICIALS. AS OF THIS TIME…NO IMPACTS BEING REPORTED OR
OBSERVED. THE COLD TEMPS AND LIGHT PCPN SYSTEMS /SNOW AS THE
PTYPE/ WILL ALLOW RIVERS AND STREAM TO CONTINUE TO RECEDE FROM
LAST WEEKS STORM SYSTEM.

BELOW NORMAL TEMPERATURES WILL ALLOW ICE TO REFORM AND THICKEN ON
BODIES OF WATER IN THE ALBANY HYDRO SERVICE AREA THROUGH THE
UPCOMING WEEK.

FOR SPECIFIC RIVER AND LAKE FORECASTS…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…BGM
NEAR TERM…HWJIV/BGM
SHORT TERM…BGM
LONG TERM…HWJIV
AVIATION…HWJIV
HYDROLOGY…BGM/WASULA

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