February 21, 2012 Forecast Discussion

000
FXUS61 KALY 211729
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1229 PM EST TUE FEB 21 2012

.SYNOPSIS…
HIGH PRESSURE WILL SHIFT EASTWARD AND OFFSHORE TODAY WITH CLOUDS ON
THE INCREASE. A WARM FRONT WILL MOVE ACROSS THE REGION TONIGHT
ACCOMPANIED BY RAIN AND SNOW SHOWERS. THE WEATHER WILL REMAIN
UNSETTLED FOR THE REST OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/…
— Changed Discussion —
CI/CS CLOUD CANOPY CONTINUES TO THICKEN AND LOWER AS UPPER LOW
NEAR DETROIT LIFTS NORTHEAST. REGIONAL RADARS SHOW SHOWER ACTIVITY
HAS MOVED INTO EXTREME WESTERN NY AND WESTERN PA. UPSTREAM METARS
SHOW A MIXTURE OF RAIN/SNOW AS THIS WILL BECOME OUR ISSUE LATER
THIS EVENING. AS FOR ARRIVAL TIMING…PER THE HRRR AND
EXTRAPOLATING RADAR TRENDS…SEEMS OUR WESTERN AREAS COULD SEE
PRECIP AS EARLY AS 4 PM EST AND INTO THE HUDSON RIVER VALLEY
AROUND 6 PM. SO HAVE MADE SLIGHT ADJUSTMENTS TO THE POPS/WX GRIDS.
OTHERWISE…TEMPERATURES LOOK ON TRACK AND LITTLE CHANGES NEEDED
AT THIS TIME.

THIS PIECE OF ENERGY WILL LOSE ITS IDENTITY TONIGHT. HOWEVER MORE
ENERGY MOVING THROUGH THE LONGWAVE TROUGH WILL BE ON ITS HEALS.
WILL HAVE WEAK FRONTAL BOUNDARY…OCCLUDING WARM FRONT MOVE ACROSS
THE REGION TONIGHT. THE BEST CHANCES FOR SHOWERS WILL BE ACROSS
THE SOUTHERN ADIRONDACKS WHERE THE BETTER UPPER SUPPORT WILL BE.
IT WILL BE COLD ENOUGH FOR MAINLY SNOW ACROSS THE SOUTHERN
ADIRONDACKS WITH UP TO A COUPLE INCHES OF SNOW EXPECTED.
— End Changed Discussion —

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/…
MODEL GUIDANCE HAS NOT BEEN CONSISTENT HANDLING THE NEXT SIGNIFICANT
PIECE OF ENERGY MOVING THROUGH THE LONGWAVE PATTERN AND HOW AND
WHERE THE LOW PRESSURE SYSTEM ASSOCIATED WITH IT DEVELOPS. AS FOR
WEDNESDAY AND WEDNESDAY NIGHT…A SURFACE LOW WILL MOVE GRADUALLY
EASTWARD ACROSS ONTARIO AND QUEBEC WHILE THE UPPER TROUGH FLATTENS
OVER OUR REGION. PIECES OF ENERGY WILL MOVE THROUGH THIS FAST FLOW
KEEPING THE THREAT FOR PRECIPITATION IN THE FORECAST. MORE
ORGANIZED/WIDESPREAD PRECIPITATION WILL BEGIN TO MOVE INTO THE
REGION THURSDAY AS A LOW PRESSURE SYSTEM APPROACHES.

EXPECTING EVEN MILDER TEMPERATURES WEDNESDAY WITH SOUTHWESTERLY FLOW
ACROSS THE AREA…SHOULD REACH 50 DEGREES IN THE CAPITAL DISTRICT.
NOT QUITE AS MILD THURSDAY BUT STILL ABOVE NORMAL BY AROUND 10
DEGREES.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/…
THE MEDIUM RANGE GUIDANCE CONTINUE TO FORECAST AN ACTIVE WEATHER
PATTERN AT THE END OF THE WEEK…AND THE BEGINNING OF THE WEEKEND.
THERE STILL IS QUITE A BIT OF UNCERTAINTY ON THE
TIMING…EVOLUTION…AND IMPACT OF A SYSTEM FRIDAY INTO
SATURDAY…AND WE ARE LEANING MORE TOWARDS AN HPC/GFS/GLOBAL
ENSEMBLE MEAN SCENARIO INTO THE FIRST HALF OF THE WEEKEND…AND THEN
FOLLOWED CLOSER TO HPC THEREAFTER.

THURSDAY NIGHT…A SFC CYCLONE APPROACHES THE FORECAST AREA FROM THE
GREAT LAKES REGION IN THE W/SW H500 FLOW ALOFT. THE WARM FRONT TO
THE CYCLONE LIFTS NORTHWARD FROM THE OHIO VALLEY. THE ISENTROPIC
LIFT STRENGTHENS FOR A PERIOD OF WET SNOW AND RAIN. THE WET SNOW
WILL LIKELY BE CONFINED TO LOCATIONS NORTH OF THE CAPITAL
REGION…AND OVER THE MOUNTAINS. LOWS WILL GENERALLY BE IN THE
LOWER TO M30S. AS THE WARM FRONT MOVES THROUGH…H850 TEMPS RISE TO
0C TO +6C BY 12Z/FRI.

FRIDAY…THE NAM IS THE FASTEST DEEPENING AND INTENSIFYING THE
CYCLONE TO 983 HPA OVER SRN QUEBEC BY 12Z. THE CAN GGEM/GFS ARE IN
PRETTY GOOD AGREEMENT THE LOW WILL BE NEAR WRN NY AND THE ERN GREAT
LAKES REGION AT THIS TIME…WHILE THE ECMWF IS MUCH SLOWER WITH THE
CYCLONE OVER THE OHIO VALLEY. THE 00Z GLOBAL ENSEMBLE MEAN IS A
COMPROMISE BTWN THE NAM AND THE GFS/CAN GGEM. HPC/S PLACEMENT OF A
992 HPA CYCLONE NEAR NIAGARA FALLS FAVORS THE GFS. THE NRN AND SRN
STREAMS CONTINUE TO SHOW SIGNS OF PHASING NEAR THE NORTHEAST DURING
THE DAY. A BROAD UPPER LEVEL TROUGH IS CARVED OUT OVER THE CENTRAL
PLAINS INTO THE MS RIVER VALLEY WITH THE NRN AND SRN STREAMS PHASING
POTENTIALLY ALONG OR JUST WEST OF THE APPALACHIAN MTNS. THE SURFACE
LOW INTENSIFIES AND DEEPENS…AS IT MOVES ACROSS NY AND NEW ENGLAND
INTO SE QUEBEC. THE ECMWF IS STUBBORNLY SLOWER AND MUCH MORE INTENSE
WITH THE CYCLONE DEVELOPMENT NEAR THE DELMARVA REGION AT 00Z/SAT.
THE GFS HAS A DRY SLOT OVER THE REGION HEADING INTO THE OVERNIGHT
PERIOD. MOST OF THE REGION WILL BE IN A WARM SECTOR WITH PERIODS OF
RAIN. THE QUESTION WILL BE HOW FAST THE COLD AIR MOVES BACK IN FROM
THE NORTH AND WEST WITH THE CYCLONE LIFTING NORTH AND EAST OF THE
REGION. AGAIN…LEANING TOWARDS HPC HERE WITH THE COLDER AIR MOVING
IN TOWARDS NIGHTFALL. HIGHS WILL BE BALMY ON FRIDAY…WITH U40S TO
M50S IN THE VALLEYS…AND LOWER TO M40S OVER THE MTNS.

FRI NIGHT…THE ECMWF HAS AN IMPRESSIVE ISALLOBARIC COUPLET
IMPACTING THE FCST AREA WITH THE STORM DEEPENING AND INTENSIFYING TO
967 HPA JUST NORTHEAST OF MONTREAL BY 12Z/SAT. THE GFS/HPC HAVE THE
DEEP STORM OF ABOUT 980 HPA OVER NRN ME/NEW BRUNSWICK. THE GFS SFC
ISALLOBARIC COUPLET ISN/T ANYWHERE NEAR AS STRONG AS THE ECMWF.
STRONG COLD AIR ADVECTION IMPACTS THE REGION WITH H850 TEMPS FALLING
BACK TO ABOUT -10C. IT WILL BE WINDY…BUT HOW WINDY IS THE
QUESTION AT THIS POINT BASED ON THE MODEL DISCREPANCIES. THE H850
WINDS FROM THE NW ARE ONLY 35-40 KTS BY 12Z/SAT ON THE GFS. WE WILL
CONTINUE TO MONITOR HOWS THINGS EVOLVE OVER THE NEXT FEW DAYS. THE
ECMWF SCENARIO WOULD BE THE WORST CASE SCENARIO WITH A POTENTIALLY
HIGH WIND EVENT. OUR CONFIDENCE IS NOT HIGH ENOUGH YET TO PLACE
THIS IN THE HWO.

SATURDAY…COLD AND WINDY CONDITIONS PREVAIL WITH NORTHWEST FLOW
ALOFT. A SERIES OF DISTURBANCES WILL BE ROTATING AROUND THE STACKED
LOW OVER THE CANADIAN MARITIMES. WE KEPT A CHANCE OF SNOW SHOWERS
IN NORTH AND WEST OF THE CAPITAL DISTRICT…AND A SLIGHT CHC SOUTH
AND EAST. MAX TEMPS WILL BE CLOSER TO SEASONABLE READINGS.

SATURDAY NIGHT…A SECOND COLD FRONT OR SFC TROUGH MOVES THROUGH
WITH H850 TEMPS FALLING TO -12C TO -15C OVER THE REGION. THIS
BOUNDARY HAS LESS MOISTURE TO WORK WITH…AND THE BEST CHC OF SNOW
SHOWERS WILL BE DOWNWIND OF LAKE ONTARIO…AND PREDOMINANTLY WEST OF
THE HUDSON RIVER VALLEY. LOWS WILL BE IN THE UPPER TEENS TO LOWER
20S IN THE VALLEYS…AND SINGLE DIGITS TO MID TEENS OVER THE MTNS.

SUNDAY TO MONDAY…FOLLOWED CLOSE TO HPC WITH HIGH PRESSURE BRIEFLY
BUILDING IN FROM SOUTH OF JAMES BAY TO CLOSE THE WEEKEND. ANY LAKE
EFFECT SNOW SHOWERS OR FLURRIES WILL END. THE NEXT CYCLONE
APPROACHES FROM THE LOWER GREAT LAKES REGION TO OPEN THE WEEK. IT
LOOKS TO PASS NORTH AND WEST OF UPSTATE NY…WITH A SLIGHT TO LOW
CHC OF RAIN AND SNOW SHOWERS. TEMPS MODERATE SLIGHTLY ABOVE NORMAL.

OVERALL…TEMPS WILL STILL RUN ABOVE NORMAL…WITH PRECIPITATION
AMOUNTS IN THE NORMAL RANGE DEPENDING ON THE FRIDAY SYSTEM.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/…
VFR CONDITIONS WILL PREVAIL THE NEXT 12-18 HOURS WITH HIGH PRESSURE
IN CONTROL INTO THE AFTERNOON. A WARM FRONT WILL APPROACH FROM THE
OHIO VALLEY. THIS BOUNDARY WILL BRING AN INCREASE OF CLOUDS…A
CHANCE OF RAIN OR SNOW SHOWERS…AND LOW LEVEL WIND SHEAR CONDITIONS
AFTER 23Z FOR NORTH OF KALB.

HIGH CLOUDS WILL INCREASE WITH THE SFC HIGH MOVING OFF THE NEW
ENGLAND COAST INTO THE AFTERNOON. THE CLOUDS WILL CONTINUE TO
THICKEN AND LOWER INTO THE EARLY EVENING WITH BASES LOWERING TO 5-7
KFT AGL AFTER 00Z/WED. THE WINDS AT THE 2 KFT AGL WILL INCREASE TO
35-40 KTS. THE SFC WINDS WINDS MAY DECREASE TO 5 KTS OR LESS AFTER
DARK ESPECIALLY AT KGFL. A LLWS GROUP WAS ADDED AT KGFL WHERE OUR
CONFIDENCE WAS GREATEST. KPOU IS MARGINALLY CLOSE TO LLWS
CONDITIONS…AND MAY BE NECESSARY WITH LATER TAF ISSUANCES…IF
CONFIDENCE INCREASES.

SOME SCT SNOW SHOWERS WILL DEVELOP AHEAD OF THE WARM FRONT…AS CIGS
AND VSBYS WILL LOWER TO MVFR LEVELS ESPECIALLY NORTH OF KALB. FOR
NOW…WE CONTINUED LOW VFR CIGS FROM KALB SOUTH. WE ALSO INCLUDED
VCSH GROUPS FOR KPOU AND KALB AT 00Z AND 03Z RESPECTIVELY.

THE WINDS WILL BE SOUTHERLY AT 7-12 KTS IN THE LATE MORNING THRU THE
AFTERNOON…WITH A FEW GUSTS CLOSE TO 20 KTS AT KALB. THE SFC WINDS
WILL LIGHTEN TO 10 KTS OR LESS AFTER 00Z/WED.

OUTLOOK….
WED…VFR. SLIGHT CHC -SHRA.
WED NIGHT…VFR/MVFR…CHC -SHRA KPOU…SLGT CHC -SHRA/-SHSN NORTH.
THU…VFR…CHC PM -SHRAS.
THU NIGHT…MVFR/VFR. CHC -RA.
FRI…MVFR CIGS/VSBYS. RA LIKELY. BECOMING WINDY.
FRI NGT-SAT…VFR. SLIGHT CHC -SHSN. WINDY.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED THIS WEEK. HIGH PRESSURE WILL MOVE
OFFSHORE TODAY AND THE WEATHER WILL BECOME UNSETTLED FOR THE REST OF
THE WEEK. THE BEST CHANCES FOR WIDESPREAD PRECIPITATION MAINLY IN
THE FORM OF RAIN WILL BE THURSDAY NIGHT AND FRIDAY WITH A TRANSITION
TO PRIMARILY SNOW AS COLDER AIR MOVES IN FRIDAY NIGHT. THE POTENTIAL
FOR FLOODING IS GENERALLY BELOW NORMAL DUE TO BELOW NORMAL SNOWPACK
AND RIVER ICE. PLEASE REFER TO OUR WINTER/SPRING FLOOD POTENTIAL
OUTLOOK (ALBESFALY) ISSUED ON FEBRUARY 16TH FOR DETAILS. NEXT
ISSUANCE OF THIS PRODUCT OS SCHEDULED FOR MARCH 1ST.

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.

&&

.CLIMATE…
LEAST SNOWIEST DEC-JAN-FEB FOR ALBANY NY
YEARS OF RECORD: 1884-2012

1) 8.8 INCHES 2011-12 (THROUGH 2/20)
2) 10.9 INCHES 1936-37
3) 11.7 INCHES 1912-13
4) 13.8 INCHES 1911-12
5) 14.2 INCHES 1988-89
6) 16.3 INCHES 1931-32
7) 16.6 INCHES 1979-80
8) 17.0 INCHES 1954-55
9) 17.1 INCHES 1918-19
17.1 INCHES 1889-90
10) 17.3 INCHES 1910-11

LEAST SNOWIEST SEASONS FOR ALBANY NY
YEARS OF RECORD: 1884-2012

1) 13.8 INCHES 1912-13
2) 14.1 INCHES 2011-12 (THROUGH FEB 20TH)
3) 19.0 INCHES 1988-89
4) 24.8 INCHES 1929-30
5) 26.7 INCHES 1918-19
6) 27.4 INCHES 1979-80
7) 28.1 INCHES 1889-90
8) 28.4 INCHES 1936-37
9) 28.7 INCHES 1990-91
28.7 INCHES 1914-15
11) 28.9 INCHES 1896-97

&&

.ALY WATCHES/WARNINGS/ADVISORIES…
CT…NONE.
NY…NONE.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…IAA
NEAR TERM…IAA/BGM/JPV
SHORT TERM…IAA
LONG TERM…WASULA
AVIATION…WASULA
HYDROLOGY…IAA
CLIMATE…IAA

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