February 10, 2012 Forecast Discussion

000
FXUS61 KALY 101154
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
654 AM EST FRI FEB 10 2012

.SYNOPSIS…
HIGH PRESSURE WILL GIVE WAY TO AN APPROACHING COLD FRONT TODAY. THE
BOUNDARY WILL MOVE ACROSS THE REGION TONIGHT INTO SATURDAY
ACCOMPANIED BY SNOW SHOWERS…WHILE USHERING IN A COLDER MORE
SEASONABLE AIRMASS. AN AREA OF LOW PRESSURE WILL DEVELOP OFF THE
SOUTHEAST COAST BY SATURDAY MORNING…THEN HEAD NORTHEASTWARD TO THE
CANADIAN MARITIMES OVER THE WEEKEND. THE LOW WILL REMAIN
OFFSHORE…HOWEVER PRECIPITATION ASSOCIATED WITH IT WILL IMPACT
PORTIONS OF THE AREA LATE TONIGHT INTO SATURDAY. IN THE WAKE OF THE
LOW…EVEN COLDER AIR WILL FILTER IN.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
— Changed Discussion —
AS OF 630 AM…FORECAST LOOKS GOOD WITH ONLY SOME MINOR ADJUSTMENTS
BASED ON OBSERVATIONAL DATA.

AS OF 4 AM…RIDGING WILL GIVE WAY TO AN APPROACHING COLD
FRONT AND DEEPENING TROUGH. CLOUDS WILL BE IN THE INCREASE DURING
THE DAY…MAINLY HIGH AND MID LEVEL. ABOVE NORMAL TEMPERATURES BY
5 TO 10 DEGREES CAN BE EXPECTED AGAIN WITH REGION UNDER BROAD
SOUTHWESTERLY FLOW.
— End Changed Discussion —

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/…
ITS GOING TO SNOW THIS WEEKEND…LIGHT SNOW ACROSS PORTIONS OF THE
FORECAST AREA. THERE WILL MULTIPLE CAUSES FOR THE SNOWFALL.

A COLD FRONT WILL MOVE INTO THE AREA TONIGHT AS A DEEPENING
TROUGH APPROACHES RESULTING IN SNOW SHOWERS ACTIVITY. IN THE
MEANTIME…THE TROUGH WILL CONTINUE TO DEEPEN ACROSS THE EASTERN
UNITED STATES AS SOUTHERN STREAM MOVES OUT OF THE SOUTHERN PLAINS.
SOME PHASING WILL OCCUR SPINNING UP AN AREA OF LOW PRESSURE OFF
THE SOUTHEAST COAST BY 12Z/SATURDAY. THIS LOW WILL THEN TRACK
NORTHWARD BEING DRAWN TOWARD THE UPPER LOW WHICH WILL SHIFT
SOUTHEASTWARD FROM THE HUDSON BAY AREA. THE LOW WILL REMAIN
OFFSHORE…HOWEVER LIGHT PRECIPITATION ASSOCIATED WITH THE LOW
AND UPPER TROUGH WILL OCCUR ACROSS THE AREA…MAINLY TO THE SOUTH
AND EAST OF THE CAPITAL DISTRICT. THE 00Z/NAM CAME IN WITH HIGHER
QPF TOTALS WHICH WERE HIGHER THAN ITS PREVIOUS RUNS AND HIGHER
THAN OTHER MODEL GUIDANCE. WENT WITH A MODEL CONSENSUS. SNOW
ACCUMULATIONS WILL BE LIGHT UNDER ADVISORY CRITERIA SO NO HEADLINES
NEEDED AT THIS TIME. THE HIGHEST TOTALS ARE EXPECTED ACROSS LITCHFIELD
COUNTY WITH 2 TO 4 INCHES…HOWEVER WILL HAVE MENTION IN OUR
HAZARDOUS WEATHER OUTLOOK THAT ADVISORY LEVEL SNOWS ARE POSSIBLE.

A LULL IN THE PRECIPITATION IS EXPECTED FOR A PERIOD SATURDAY
EVENING WITH LAKE ENHANCED SNOW SHOWERS DEVELOPING AT NIGHT AND
CONTINUING INTO SUNDAY NIGHT AS COLDER AIR IN DRAWN INTO THE
REGION IN THE WAKE OF THE LOW.

BETWEEN THE COLD AIR AND BRISK AND GUSTY WINDS…WIND CHILL ADVISORY
CRITERIA MAY BE REACHED ACROSS THE HIGHER TERRAIN SATURDAY NIGHT INTO
SUNDAY AND AGAIN SUNDAY NIGHT INTO MONDAY…SO WILL CONTINUE TO
MENTION IN OUR HAZARDOUS WEATHER OUTLOOK.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/…
THE EXTENDED BEGINS WITH ANY LAKE EFFECT IN NW FLOW ENDING OVER
CNTRL NY…AS A WEAK RIDGE OF HIGH PRESSURE AT THE SFC BUILDS IN
ACROSS UPSTATE NY AND NEW ENGLAND FROM SOUTHEASTERN CANADA. THE
CORE OF THE COLDEST AIR WITH THE POLAR VORTEX CONTINUES TO LIFT N/NE
OVER ERN QUEBEC AND THE CANADIAN MARITIMES. WEAK LOW TO MID LEVEL
WARM ADVECTION INCREASES DURING THE DAY…AS A WARM FRONT WILL BE
APPROACHING FROM THE GREAT LAKES REGION AND THE OHIO VALLEY. H850
TEMPS WARM TO -10C TO -16C FROM SOUTH TO NORTH ACROSS THE REGION.
MAX TEMPS LOOK SEASONABLE WITH LOWER TO M30S IN THE VALLEYS /EXCEPT
SOME U30S IN THE MID HUDSON VALLEY/…AND M20S TO L30S OVER THE
HILLS AND MTNS. SEASONABLY COLD AND DRY WX PERSISTS OVERNIGHT…WITH
JUST A SLIGHT CHC OF THERMAL ADVECTION SNOW SHOWERS NEAR THE WRN
DACKS…WITH LOWS IN THE TEENS OVER THE HIGHER TERRAIN…AND UPPER
TEENS TO LOWER 20S IN THE VALLEY.

TUESDAY INTO WEDNESDAY…THE MID LEVEL FLOW BECOMES LESS
AMPLIFIED…AND MORE ZONAL. A SHORT-WAVE TROUGH IN THE NORTHERN
BRANCH OF THE UPPER JET ENCROACHES THE REGION FROM THE MIDWEST/LOWER
GREAT LAKES REGION LATE TUE. THE LIFT FROM THE SYSTEM ISN/T VERY
STRONG. THE GFS/ECMWF/HPC GUIDANCE HINTS AT WEAK MOISTURE
CONVERGENCE WITH THE WEAK SYNOPTIC FORCING. THE TIMING OF THE TROUGH
VARIES IN THE FAST FLOW WITH THE MEDIUM RANGE GUIDANCE. WE HAVE A
SLIGHT TO LOW CHC OF RAIN OR SNOW SHOWERS IN FOR THE REGION. TEMPS
CONTINUE TO MODERATE BACK ABOVE NORMAL IN THE W/SW FLOW. MAX TEMPS
WILL REACH THE UPPER 30S TO L40S IN THE VALLEYS…WITH LOWER TO M30S
OVER THE HILLS AND MTNS.

WEDNESDAY NIGHT INTO THURSDAY… HIGH PRESSURE BRIEFLY BUILDS BACK
IN FROM THE OHIO VALLEY OVER THE NORTHEAST BASED ON THE
GEFS/GFS/ECMWF/HPC GUIDANCE WEDNESDAY NIGHT INTO THURSDAY MORNING.
THE GFS FAVOR A MORE SUBTROPICAL JET/SOUTHERN STREAM CYCLONE MOVING
NORTHEAST FROM THE LOWER MS RIVER VALLEY LATE THU. THE ECMWF KEEPS
THE SPLIT FLOW REGIME WITH A COMPACT NRN STREAM DISTURBANCE MOVING
EASTWARD FROM THE GREAT LAKES REGION. THE SOUTHERN STREAM WAVE
REMAINS UNPHASED. WE LEANED CLOSER THE ECMWF LATE IN THE EXTENDED
WITH A SLIGHT TO LOW CHC OF RAIN OR SNOW SHOWERS WITH THE NRN STREAM
IMPULSE. H850 TEMPS ON THE ECMWF ARE STILL A SHADE ABOVE NORMAL AT
-6C TO -8C WITH HIGHS FORECASTED IN THE 40-45F RANGE STILL COMMON IN
THE VALLEYS…AND MID TO U30S OVER THE MTNS.

OVERALL…NO MAJOR SYSTEMS AT THIS POINT IN THE LONG TERM…WITH
TEMPS STILL AVERAGING ABOVE NORMAL…AND PCPN BELOW NORMAL.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/…
— Changed Discussion —
.AVIATION /12Z FRIDAY THROUGH TUESDAY/…
HIGH PRESSURE WILL MOVE OFF THE MID ATLANTIC COAST THIS MORNING. A
COLD FRONT WILL SLOWLY APPROACH FROM SOUTHERN ONTARIO…AND SOUTHERN
QUEBEC DURING THE AFTERNOON INTO THE EVENING. MEANWHILE…LOW
PRESSURE MOVING NORTHEAST FROM THE MID ATLANTIC REGION WILL BRING
SOME LIGHT SNOW INTO PORTIONS OF EASTERN NY AND NEW ENGLAND SATURDAY
MORNING.

VFR CONDITIONS WILL DOMINATE PRIOR TO MIDNIGHT. MID AND HIGH CLOUDS
WILL BEGIN OVERSPREADING ERN NY LATE THIS MORNING THROUGH THE
AFTERNOON. THE CLOUDS WILL CONTINUE TO THICKEN AND LOWER AFTER
00Z/SAT WITH CIGS AROUND 5-6 KFT AGL PRIOR TO MIDNIGHT. SCT SNOW
SHOWERS AND/OR LIGHT SNOW WILL MOVE OVER THE KGFL/KALB/KPOU CORRIDOR
BTWN 06Z-09Z. WE PLACED A PERIOD OF MVFR CONDITIONS /CIGS AND
VSBYS/. THERE MAYBE A WINDOW OF IFR CONDITIONS IN THE
SNOW…ESPECIALLY NEAR KPOU AFTER 09Z/SAT…WHICH LATER TAF
ISSUANCES CAN ADDRESS.

THE WINDS WILL BE LIGHT TO CALM AFTER SUNRISE…AND THEN BE FROM THE
S/SW AT 5-10 KTS DURING THE LATE MORNING AND AFTERNOON…AND LIGHTEN
OVERNIGHT FROM THE W/SW AT 5 KTS OR LESS.

OUTLOOK…
SAT PM…VFR-MVFR. -SHSNS LIKELY KALB NORTH. -SN LIKELY ESPECIALLY
LATE AT NT AND SAT AM AT KPOU.
SAT NT…MAINLY VFR. SLIGHT CHC-CHC -SHSN.
SUN…VFR-MVFR. CHC -SHSN AT KALB AND SLIGHT CHC KGFL AND KPOU.
SUN NT-MON NT…VFR. NO SIG WX.
TUE…VFR/MVFR. SLIGHT CHC -SHRAS/-SHSNS.
— End Changed Discussion —

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED INTO NEXT WEEK. SOME GAGES WILL
CONTINUE TO BE IMPACTED BY ICE ACROSS NORTHERN PORTIONS OF THE
HYDROLOGIC SERVICE AREA.

COLDER AIR WILL BE USHERED IN THE REGION THIS WEEKEND AND LIGHT SNOW
IS EXPECTED. THE COLDER TEMPERATURES MAY ALLOW ADDITIONAL ICE
FORMATION TO OCCUR LATE SATURDAY INTO EARLY MONDAY…ESPECIALLY
ACROSS THE SOUTHERN ADIRONDACKS…AND AREAS NORTH OF THE MOHAWK
RIVER VALLEY. TEMPERATURES WILL GRADUALLY MODERATE NEXT WEEK.

FRIGID TEMPERATURES THIS WEEKEND MAY ALLOW ADDITIONAL ICE
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…IAA
NEAR TERM…IAA
SHORT TERM…IAA
LONG TERM…WASULA
AVIATION…WASULA
HYDROLOGY…IAA

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