January 19, 2012 Forecast Discussion

000
FXUS61 KALY 192202
AFDALY

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

.SYNOPSIS…
HIGH PRESSURE WILL CONTINUE TO LINGER OVER THE REGION INTO THE
AFTERNOON…THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL IMPACT OUR
REGION LATE BY THIS EVENING…BRINGING SOME LIGHT SNOW AND SNOW
SHOWERS. A MORE SIGNIFICANT STORM MAY IMPACT OUR REGION LATE FRIDAY
NIGHT THROUGH SATURDAY AS IT MOVES FROM THE TENNESSEE VALLEY ACROSS
THE MIDDLE ATLANTIC REGION.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 1230 PM…HAD TO BACK OFF THE ARRIVAL OF CLOUDS AND ANY SNOW
PER SURFACE OBS. RADARS INDICATED THE SNOW SHOWERS WERE JUST
ENTERING BUFFALO. THE HRRR EXPERIMENTAL MODEL DOES INDICATE RETURNS
OF NEAR 20 DBZ NOT REACHING ALBANY UNTIL 00Z. PREVIOUS PACKAGE HAD
IT ARRIVING A FEW HOURS. THE AIR IS VERY DRY(AS WAS OUR 12Z RAOB)
AND WILL LIKELY CAUSE THE INITIAL SURGE OF MOISTURE TO EVAPORATE.

NO CHANGE ON HIGH TEMPERATURES BASED ON THIS 12Z RAOB WHICH WHEN
FULLY MIXING THE LOW LEVEL INVERSION GAVE ALBANY A HIGH OF 26. WE
ARE ALREADY 23…SO UPPER 20S LOOKS HERE…LOWER 30S SOUTH AND 20-25
MOST OTHER PLACES…EXCEPT TEENS FAR NORTH AND HIGHEST ELEVATION.
ALL PRECIPITATION SHOULD BE SNOW WITH THIS SYSTEM…BUT FINAL
SNOWFALL AMOUNTS STILL NOT ETCHED IN STONE. FOR NOW…LEFT CURRENT
THINKING FROM TONIGHT ALONE AS WE CONTINUE TO ACCESS ON THE NEW
INCOMING DATA.

FOR THE NEXT SEVERAL HOURS…LOOK FOR SUNSHINE TO BE FOLLOWED BY
RAPID INCREASING CLOUDS FROM THE WEST AND ANY SNOW LIKELY TO HOLD
OFF CERTAINLY FROM THE HUDSON VALLEY EAST…POSSIBLY REACHING OUR
SOUTHERN ADIRONDACKS BY 400 PM.

PREVIOUS NEAR TERM FORECAST**

AS OF 950 AM EST…A CLIPPER LOW CONTINUES TO QUICKLY APPROACH
FROM SOUTHEASTERN ONTARIO THIS AFTERNOON. THE HIGH CLOUDS IN
ADVANCE OF A WEAK WARM FRONT CONTINUES TO OVERSPREAD THE REGION.
THE DENSER CANOPY OF CLOUDS IS OVER WRN NY. WE RETOOLED THE CLOUD
TRENDS AND THE POP/WX TRENDS BASED ON THE LATEST NAM/HRRR. THE
WARM ADVECTION LIGHT SNOW/SNOW SHOWERS DOESN/T LOOK LIKE IT WILL
MOVE INTO MOST OF THE REGION UNTIL AFTER 23Z /6 PM/. THE BEST
CHANCE OF SOME SNOW IN THE LATE AFTERNOON IS OVER THE WRN DACKS.
WE INCREASED THE POPS TO LIKELY THERE. THE 12Z KALB SOUNDING IS
VERY DRY…AND IT WILL TAKE A LITTLE TIME TO SATURATE. THINKING
REMAINS FOR THE HIGHEST TOTALS ACROSS THE SRN DACKS…SRN
GREENS…NRN BERKS…AND PARTS OF THE MOHAWK VALLEY WITH 2-4 INCHES.
AN INCH OR TWO IS POSSIBLE FROM THE CAPITAL REGION NORTHWARD INTO THE
LAKE GEORGE REGION AND WEST INTO THE ERN CATSKILLS. AN INCH OR LESS
IS POSSIBLE IN THE MID HUDSON VALLEY…SRN TACONICS SOUTHWARD.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/…
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 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 /21Z THURSDAY THROUGH TUESDAY/…
VFR CONDITIONS WILL PERSIST INTO THE EVENING HOURS AT ALL OUR TAFS.
LOW PRESSURE NORTH OF THE GREAT LAKES REGION…WILL DRAG A COLD
FRONT THROUGH LATER TONIGHT. THERE MIGHT BE A BURST OF SNOW WITH
THIS FEATURE…BUT IT SHOULD NOT LAST LONG AND IFR CONDITIONS LOOK
TO BE BRIEF IF AT ALL. KGFL HAS THE BEST CHANCE OF EXPERIENCING IFR
BUT EVEN HERE FOR NOW…WE KEPT THEM (AS ALL OF THE OTHER TAFS) MVFR
AS CONFIDENCE REMAINS TOO LOW TO INCLUDE. (UNDER 50 PERCENT).

THIS LOW PRESSURE SYSTEM WILL BE QUICK MOVING…WITH ONLY VCSH
EXPECTED BY 08Z/KALB…09Z/KGFL AND 10Z/KPOU. ANY REMAIN SNOW
SHOWERS WILL BE SHORT LIVED AS SUBSIDENCE BEHIND THE COLD FRONT
ACCOMPANYING THE SYSTEM WILL MOVE OVER THE AREA MID TO LATE
FRIDAY MORNING. THIS SUBSIDENCE WILL ALSO HELP DECREASE CLOUD
COVER.

WINDS WILL BE OUT OF THE SOUTH AT 3-8 KTS…WITH KALB
EXPERIENCING SOME GUSTS TO 18 KTS. OVERNIGHT…WINDS WILL SHIFT
BEHIND THE COLD FRONT FROM SOUTH TO W SOMETIME BETWEEN 08Z AND 10Z
THEN INCREASE IN THE MID TO LATE MORNING AND THROUGH THE DAY.

OUTLOOK…
FRI…VFR…NO SIG WX.
SAT…SUB-VFR…CIG. SNOW..ESPECIALLY FROM ALBANY SOUTH.
SUN…VFR…NO SIG WX.
MON-TUE…SUB-VFR…CIG. CHC -RA/-SN.

&&

.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…NONE.
MA…NONE.
VT…NONE.

&&

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

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