January 19, 2012 Forecast Discussion

000
FXUS61 KALY 200301
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1001 PM EST THU JAN 19 2012

.SYNOPSIS…
A FAST MOVING CLIPPER WILL BRING A ROUND OF SNOW SHOWERS
TO THE REGION TONIGHT. ANOTHER AREA OF LOW PRESSURE TRACKING FROM
THE TENNESSEE VALLEY THROUGH THE MID ATLANTIC WILL BRING SOME
ADDITIONAL LIGHT SNOW FOR FRIDAY NIGHT INTO SATURDAY…ESPECIALLY
FOR AREAS TO THE SOUTH OF ALBANY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 1000 PM…ISSUED A SHORT FUSED WINTER WEATHER ADVISORY FOR
HERKIMER COUNTY FROM LATE THIS EVENING THROUGH THE OVERNIGHT
HOURS…AS SIGNIFICANT RADAR RETURNS OVER AN AREA BETWEEN ROUTE 8
AND 28 HAS LIKELY BEEN RESULTING IN A FEW TO SEVERAL INCHES OF
SNOWFALL THIS EVENING. HAVE NOT RECEIVED ANY REPORTS FROM THE
DIRECT AREA BUT STRONG SOUTH-SOUTHWEST FLOW IN THE LOW LEVELS
CONTRIBUTING AN UPSLOPE COMPONENT RESULTING IN MODERATE SNOW
ACROSS THE HIGHER TERRAIN NORTH OF I-90 IN HERKIMER COUNTY. THE
UPSLOPE SNOWS SHOULD DIMINISH WITHIN THE NEXT FEW HOURS AS A COLD
FRONT WILL PASS THROUGH AND SHIFT THE WINDS TO A WESTERLY
DIRECTION. HOWEVER…A LINE OF SNOW SQUALLS WITH WIND WILL PASS
THROUGH ASSOCIATED WITH THE FRONT…THEN SOME LAKE ENHANCED SNOWS
AND WESTERLY UPSLOPE WILL LIKELY SET UP BEHIND THE FRONT. SO WILL
MENTION GENERAL ACCUMULATIONS OF 3-6 INCHES IN HERKIMER
COUNTY…BUT 4-8 ACROSS THE AREA AFFECTED BY THE SOUTHERLY UPSLOPE
PREVIOUSLY MENTIONED. MADE SOME ADJUSTMENTS ELSEWHERE TO INCREASE
ACCUMULATIONS TO AROUND 2-4 INCHES ACROSS THE EASTERN CATSKILLS.

A BROKEN LINE OF SNOW SQUALLS MAY STILL MOVE ACROSS THE ENTIRE
AREA ASSOCIATED WITH THE COLD FRONT PASSAGE. WILL HAVE TO SEE IF
THIS LINE WEAKENS AS IT APPROACHES FROM CENTRAL NY. WILL MENTION A
PERIOD OF NUMEROUS SNOW SHOWERS FOR ALL AREAS TO ACCOUNT FOR THE
POTENTIAL FOR SNOW SHOWERS AND SOME SQUALLS TO MOVE THROUGH.

PREVIOUS NEAR TERM DISCUSSIONS…

SNOW SHOWERS ARE BEGINNING TO DEVELOP ACROSS THE AREA…AS SEEN ON
THE KENX AND KBGM RADARS. FURTHER WEST…A STRONGER LINE OF SNOW
SHOWERS/SQUALLS ASSOCIATED WITH AN ARCTIC BOUNDARY IS EVIDENT ON
THE KBUF RADAR…ALTHOUGH THIS LINE IS MOST LIKELY ENHANCED DUE TO
THE PROXIMITY TO LAKE ONTARIO. THE LOCAL 12 UTC HIRES WRF SHOWS
THIS LINE OF SNOW SHOWERS WEAKENING AS IT APPROACHES CENTRAL NY BY
MIDNIGHT. AS A RESULT…WE WILL BE FOCUSED ON THESE DEVELOPING
SNOW SHOWERS ACROSS OUR AREA AHEAD OF THIS LINE. AS OF RIGHT
NOW…THESE SNOW SHOWERS ARE FIGHTING A LOT OF DRY AIR AT THE
SURFACE…SO THE RADAR MAY LOOK A LITTLE WORSE THAN WHAT IS
ACTUALLY OCCURRING. STILL…SOME FLAKES WILL BEGIN TO FALL…ESP
ACROSS THE CAPITAL REGION/SOUTHERN DACKS/SARATOGA REGION OVER THE
NEXT SEVERAL HOURS. ACCUMULATIONS WILL VARY…BUT MODEL QPF IS
GENERALLY FAIRLY LIGHT OVER THE REGION /RANGING FROM A FEW
HUNDREDTHS IN VALLEY AREAS TO 0.15 INCHES OVER THE HIGH TERRAIN/ .
WITH DECENT SNOW TO LIQUID RATIOS EXPECTED /AT LEAST CLIMO WHICH
IS 12.5:1/…MOST AREAS SHOULD GET AT LEAST A FRESH COATING OF
SNOWFALL…WITH A FEW SPOTS IN THE HIGHER ELEVATIONS THAT SEE
REPEATED SNOW SHOWERS /SUCH AS UPSLOPE FAVORED AREAS OF THE
SOUTHERN GREENS…BERKSHIRES AND DACKS/ RECEIVING UP TO 2 INCHES.
THE SNOW SHOWER THREAT SHOULD END AROUND 06 UTC TO 08 UTC FROM
WEST TO EAST. HOWEVER…SOME LAKE EFFECT MAY ADD TO THE SNOW
TOTALS FOR THE WESTERN ADIRONDACKS FOR LATE TONIGHT BEHIND THE
ARCTIC FRONT…ALTHOUGH ANY LAKE EFFECT SHOULD BE BRIEF AND ONLY
CONTRIBUTE AN EXTRA INCH OR SO…AS THE BAND WILL BE QUITE
TRANSITORY AS THE WIND SHIFT DIRECTION.

MIN TEMPS WILL RANGE FROM THE SINGLE DIGITS IN THE WESTERN
ADIRONDACKS TO THE LOW 20S IN THE MID HUDSON VALLEY AND CAPITAL REGION.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/…
A BRIEF VISIT BY HIGH PRESSURE ON FRIDAY…THEN ANOTHER FAST MOVING
SYSTEM WILL AFFECT THE REGION LATE FRIDAY NIGHT AND SATURDAY. THIS
LOW PRESSURE SYSTEM IS TRACKING FROM THE TENNESSEE VALLEY AND WILL
HAVE MORE MOISTURE TO WORK WITH. IT IS NEVERTHELESS AN OPEN WAVE
WITH NOT A LOT OF DYNAMICS. FOR ONCE…THIS SYSTEM LOOKS TO BE
PRETTY MUCH ALL SNOW ACROSS OUR REGION. THERE MIGHT BE A LITTLE
SPOTTY FREEZING DRIZZLE AT THE TAIL END OF THE STORM AS THE MODELS
INDICATE THE CLOUDS WILL LOOSE THEIR ICE AT THAT POINT.

THEREFORE WE CONTINUE OUR THINKING THAT THIS WILL NOT BE A MAJOR
STORM BUT LOOKS TO BRING ADVISORY LEVEL SNOW SOUTH OF CAPITAL
DISTRICT.

THE SNOW LOOKS TO SPREAD INTO THE REGION FROM SOUTHWEST TO NORTHEAST
PRIOR TO OR AROUND DAYBREAK ON SATURDAY AS THE SURFACE LOW TRACKS
WELL SOUTH OF THE MASON DIXON LINE. FAIRLY GOOD ISENTROPIC LIFT AND
A DECENT (BUT NOT IMPRESSIVE) FRONTOGENTIC BAND WILL PASS ACROSS OUR
SOUTHERN AREAS. THERE MIGHT BE A PRETTY SHARP CUTOFF IN THE SNOW
WELL NORTH OF THE CAPITAL DISTRICT. FOR NOW…WE HAVE CATEGORICAL
POPS SOUTH OF THE CAPITAL DISTRICT…LIKELY CAPITAL DISTRICT AND
CHANCES NORTH.

SNOW WILL LIKELY BECOME MODERATE FOR A AWHILE FROM JUST SOUTH OF
ALBANY…BUT THIS WILL BE ANOTHER FAST MOVING SYSTEM WHICH WILL HELP
PREVENT HEAVIER AMOUNTS. LIQUID TO SNOW RATIOS LOOK A LITTLE HIGHER
THAN THE CLIMATOLOGICAL 13:1…ESPECIALLY FROM ALBANY NORTHWARD.

THAT SAID…THE 18Z NAM CAME IN WITH SLIGHTLY HIGHER AMOUNTS OF QPF
AGAIN AND WOULD IMPLY ADVISORY LEVELS RIGHT UP TO THE CAPITAL
DISTRICT. FOR NOW THOUGH…WE WILL CONTINUE WITH THE PREVIOUS
THINKING OF A 2-4 INCH SNOWFALL GREATER CAPITAL REGION…MOHAWK
VALLEY…NORTHERN BERKSHIRES AND SOUTHERN VERMONT. FURTHER
SOUTH…4-6 INCHES CAN BE EXPECTED ACROSS THE CATSKILLS…MUCH OF
THE MID HUDSON VALLEY…SOUTHERN BERKSHIRES…AND LITCHFIELD COUNTY.

THE SNOW LOOKS TO WIND DOWN…AGAIN POSSIBLY ENDING AS LITTLE
FREEZING DRIZZLE DURING THE AFTERNOON ON SATURDAY. (WE DID NOT
MENTION ANY FREEZING DRIZZLE IN THE GRIDS SINCE THE CONFIDENCE OF
THIS HAPPENING WAS STILL RATHER LOW).

HIGH TEMPERATURES LOOK TO BE 25-30 MOST PLACES ON SATURDAY…20 TO
25 WELL NORTH OF ALBANY.

HIGH PRESSURE LOOKS TO BUILD BACK FROM EASTERN CANADA SATURDAY NIGHT
INTO SUNDAY. IF WE CLEAR OUT SATURDAY NIGHT AND GET A DECENT
SNOWPACK…TEMPERATURES COULD GET QUITE COLD BY SUNDAY MORNING. WE
FEEL PRETTY CONFIDENT THE SKY WILL CLEAR…AT LEAST NORTH OF ALBANY.
HOWEVER THE SNOW PACK WILL BE LESS IN THAT VICINITY.

FOR NOW…FOLLOWED A BLEND OF THE MET/MAV GUIDANCE WHICH GAVE US
COLD TEMPS UP NORTH WITH LOTS OF SINGLE NUMBERS…TEENS SOUTH.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/…
AN AREA OF HIGH PRESSURE WILL MOVE FROM JUST NORTH OF THE REGION ON
SUNDAY MORNING TO JUST EAST OF NORTHERN MAINE BY SUNDAY EVENING.
ENOUGH SUBSIDENCE WILL BE IN PLACE OVER OUR REGION TO ALLOW FOR A
DRY DAY ON SUNDAY WITH PARTLY TO MOSTLY SUNNY SKIES AND TEMPS CLOSE
TO SEASONAL AVERAGES /GENERALLY UPPER 20S TO MIDDLE 30S/.

CLOUDS WILL BEGIN TO INCREASE ON SUNDAY EVENING AS A STRONG STORM
SYSTEM DEEPENS OVER THE NORTHERN GREAT LAKES. A SOUTHERLY LOW LEVEL
JET OF 40-50 KTS AROUND 850 HPA WITH BEGIN TO TRANSPORT WARMER AIR
ALOFT INTO THE REGION. SFC TEMPS WON/T DROP OFF MUCH AT ALL. FOR
NOW…WE HAVE TEMPS BASICALLY STEADY OVERNIGHT…ALTHOUGH THE LOW
MAY WIND UP ACTUALLY BEING IN THE LATE EVENING WITH TEMPS RISING
OVERNIGHT. THE SOUTHERLY FLOW WILL ALLOW FOR SOME WEAK ISENTROPIC
LIFT AND MAY ALLOW FOR A PERIOD OF LIGHT PRECIPITATION OVERNIGHT.
WITH SFC TEMPS BELOW FREEZING IN MANY PLACES…THE PRECIP WILL BEGIN
AS A WINTRY MIX. THE LATEST 12 UTC GFS BUFR SOUNDINGS SHOW THAT A
SNOW/SLEET MIX MAY QUICKLY CHANGE TO RAIN OR FREEZING RAIN DEPENDING
ON THE BOUNDARY LAYER TEMPS. THIS FZRA MAY HANG ON FOR A FEW HOURS
EVEN INTO MONDAY MORNING /MAINLY ACROSS THE SOUTHERN GREENS OR
DACKS/ BEFORE TEMPS WARM UP ENOUGH EVERYWHERE FOR JUST PLAIN RAIN
SHOWERS. TEMPS SHOULD WARM UP WELL INTO THE 40S IN MOST PLACES AS
THE STRONG LOW LIFTS INTO SOUTHERN CANADA.

THE STORM/S COLD FRONT SHOULD PASS THROUGH THE REGION DURING THE
EVENING HOURS ON MONDAY. THIS WILL ALLOW TEMPS TO FALL DOWN
SOMEWHAT AND END THE THREAT FOR WIDESPREAD PRECIP. TEMPS WILL BE
COOLER FOR TUESDAY…BUT STILL A LITTLE ABOVE NORMAL…WITH MAX
TEMPS NEAR 40 FOR THE CAPITAL REGION. IT WILL GENERALLY BE DRY FOR
TUESDAY INTO WEDNESDAY AS WEAK HIGH PRESSURE PASSES OVER THE AREA.
TEMPS ON WED WILL CONTINUE TO BE A LITTLE ABOVE NORMAL FOR MOST
AREAS…WITH UPPER 30S IN THE CAPITAL REGION.

THE MODELS DISAGREE SOMEWHAT FOR THURSDAY. THE LATEST 12 UTC ECMWF
SHOWS A WEAK NORTHERN STREAM CLIPPER STORM MOVING ACROSS THE
AREA…WHILE THE 12 UTC GFS SHOWS A LITTLE DEEPER LOW MOVING TO THE
SOUTH OF THE REGION. IN EITHER SCENARIO…WE WOULD HAVE A CHANCE
OF SOME LIGHT SNOWFALL…SO WILL GO WITH CHC POPS FOR LIGHT
SNOW…ALTHOUGH QPF WILL DEPEND ON JUST HOW THE STORM TRACKS. WITH
THIS BEING VERY FAR OUT…IT/S BOUND TO CHANGE SEVERAL TIMES WITH
SUBSEQUENT MODEL RUNS…SO IT/S A LOW CONFIDENCE FORECAST AT THIS
TIME. FOR NOW…WITH THE EXPECTED CLOUDS/PRECIP…WILL FORECAST
TEMPS A LITTLE CLOSER TO SEASONAL NORMALS…WITH LOWER TO MIDDLE 30S
FOR MANY AREAS.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/…
CONDITIONS ARE CURRENTLY VFR AT ALL TAF SITES. SOME SNOW SHOWERS
ARE BEGINNING TO DEVELOP ON THE REGIONAL RADAR MOSAIC TO THE WEST
OF KALB/KGFL. THESE TWO SITES MAY SEE SOME BRIEF SNOW SHOWERS
THROUGH ABOUT 06 UTC…WITH POSSIBLY SOME MVFR VSBYS. AT THIS
POINT…WE DO NOT ANTICIPATE ANY WIDESPREAD IFR CONDITIONS…SO
WILL LEAVE OUT OF TAF AT THIS TIME. FURTHER SOUTH…KPOU SHOULD
ONLY SEE FLURRIES OR VERY LIGHT SNOW SHOWERS…AND CONDITIONS
SHOULD REMAIN MAINLY VFR.

SOUTHERLY WINDS WILL BE GUSTY AT TIMES THIS EVENING. A FEW GUSTS
MAY EVEN APPROACH 20-25 KTS…MAINLY AT KGFL/KALB. AS THE NIGHT
WEAR ON…THE GUSTS SHOULD BEGIN TO DIMINISH.

A FRONTAL BOUNDARY WILL CROSS LATE TONIGHT…ENDING THE THREAT OF
SNOW SHOWERS AND CHANGING THE WIND TO A WESTERLY DIRECTION. CLOUDS
WILL DIMINISH AND SKIES WILL BE MAINLY CLEAR FOR FRIDAY…EXCEPT
FOR SOME PASSING THIN HIGH CIRRUS CLOUDS. WINDS ON FRIDAY WILL
GENERALLY BE FROM A WNW DIRECTION. A FEW GUSTS…ESP IN THE
AFTN…MAY ONLY AGAIN APPROACH 20 KTS.

OUTLOOK…
FRI NIGHT-SAT…IFR/MVFR. -SN LIKELY.
SUN…VFR…NO SIG WX.
SUN NIGHT-MON…MVFR/IFR. CHC -RA/-SN/-PL/-FZRA.
TUE…VFR. NO SIG WX.

&&

.HYDROLOGY…
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH THE
WEEKEND AS ANY PRECIPITATION WHICH FALLS WILL BE IN THE FORM OF SNOW.

A CLIPPER TYPE SYSTEM WHICH IS EXPECTED TO BRIEF BURST OF SNOW TO
MANY LOCATIONS TONIGHT. QPF AMOUNTS WILL BE LESS THAN A QUARTER OF
AN INCH AND SINCE IT WILL BE ALL SNOW NO IMPACT ON ANY WATERSHEDS.

A MORE SIGNIFICANT STORM IS EXPECTED TO TRACK FROM THE TENNESSEE
VALLEY TOWARD THE MIDDLE ATLANTIC COAST BRINGING A GENERALLY LIGHT
TO MODERATE SNOWFALL TO THE REGION LATE FRIDAY NIGHT INTO SATURDAY
WITH THE POTENTIAL FOR HEAVIER SNOW ACROSS THE HIGHER TERRAIN SOUTH
AND EAST OF CAPITAL DISTRICT. SINCE AGAIN IT LOOKS TO BE ALL
SNOW…NO IMPACT ON ANY OUR WATERSHEDS.

ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE END OF THE WEEK AS COLD AIR WILL BE IN PLACE ACROSS
THE REGION.

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…WINTER WEATHER ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-038.
MA…NONE.
VT…NONE.

&&

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

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