February 7, 2014 Forecast Discussion

000
FXUS61 KALY 071327
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
827 AM EST FRI FEB 7 2014

.SYNOPSIS…
HIGH PRESSURE WILL DOMINATE OUR WEATHER THROUGH SATURDAY. IT WILL
BE COLD WITH MAINLY DRY WEATHER…SOME LAKE EFFECT SNOW SHOWERS
WILL OCCUR INTO THE WESTERN ADIRONDACKS. A SERIES OF COLD FRONTS
WILL CROSS THE REGION SUNDAY AND MONDAY WITH SOME LIGHT SNOWFALL.
HIGH PRESSURE WILL BUILD BACK INTO THE NORTHEAST TUESDAY AND
WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/…
AN UPPER LEVEL DISTURBANCE EMBEDDED WITHIN MAINLY ZONAL FLOW
ALOFT IS IN THE PROCESS OF MOVING ACROSS UPSTATE NY. THIS NORTHERN
STREAM FEATURE IS RATHER MOISTURE STARVED…AND IS DOING LITTLE
SYNOPTICALLY OTHER THAN PRODUCING SOME A BATCH OF CLOUDS AND
SOME FLURRIES AS IT PASSES.

MEANWHILE…THE PERSISTENT W-SW FLOW IN THE LOW AND MID LEVELS
AHEAD OF THIS DISTURBANCE IS ALLOWING FOR A BAND OF LAKE EFFECT
SNOW OFF LAKE ONTARIO. DESPITE LOW INVERSION HEIGHTS AND THE LACK
OF A MULTI-LAKE CONNECTION…THE LONG FETCH ACROSS LAKE ONTARIO IS
ALLOWING FOR SOME MODERATE TO HEAVY SNOW WITHIN THIS BAND…AND AN
INLAND EXTENT REACHING INTO THE NORTHWESTERN ADIRONDACKS. HOWEVER…THE
ORIENTATION OF THE BAND IS KEEPING THE HEAVIEST ECHOES TO THE WEST
AND NORTH OF OUR AREA. OVER THE NEXT FEW HOURS…THIS BAND WILL
SLOWLY START TO WEAKEN AND DRIFT SOUTH…IMPACTING THE FAR
NORTHWESTERN CORNER OF OUR CWA…WHICH IS MOSTLY UNINHABITED
FOREST PRESERVE OF THE ADIRONDACKS. THE APPROACHING UPPER LEVEL
DISTURBANCE WILL DISRUPT THE FLOW ENOUGH BY THE LATE MORNING HOURS
TO SIGNIFICANTLY DECREASE THE INTENSITY AND EXTENT OF THIS BAND.
BEFORE THAT OCCURS…AN INCH OR TWO OF ACCUMULATION IS POSSIBLE
ACROSS FAR NORTHERN PORTIONS OF HERKIMER COUNTY. THIS MOVEMENT AND
WEAKENING IS SHOWN IN THE 09Z 3KM HRRR COMPOSITE REFLECTIVITY
FORECAST PRODUCT…AS WELL AS THE 06Z RUN OF OUR LOCAL HIRESWRF.
BY THE AFTN…WE WILL DECREASE POPS ACROSS THE REGION…WITH THE
BEST SNOW BY THAT POINT LIMITED TO AREAS NEAR THE LAKE SHORE OF
LAKE ONTARIO.

OTHERWISE…IT WILL REMAIN MAINLY DRY OVER THE REMAINDER OF THE
REGION TODAY…WITH JUST SOME PASSING CLOUDS. CAN/T TOTALLY RULE OUT
A FEW FLURRIES WITH THE PASSING UPPER LEVEL DISTURBANCE FOR WESTERN
PARTS OF THE AREA THIS MORNING /BASED ON CURRENT UPSTREAMS OBS IN
CENTRAL NY/…BUT NO MEASURABLE SNOW ACCUMULATION IS EXPECTED.
WINDS WILL PICK UP DURING THE AFTERNOON HOURS AS THE SHORTWAVE MOVES
ACROSS THE REGION…WITH SOME GUSTS IN THE 10-20 MPH RANGE…ESP IN
AREAS OF CHANNELED FLOW.

SOME SHELTERED AREAS THAT HAD NO WIND AND HAD MAINLY CLEAR SKIES GOT
VERY COLD THIS MORNING…SUCH AS IN THE GLENS FALLS AREA…WHERE
IT DROPPED AS LOW AS -13 DEGREES. ELSEWHERE…TEMPS WERE NEAR
ZERO OR IN THE SINGLE DIGITS. ONCE THE SUN COMES UP…TEMPS WILL
STEADILY WARM UP THROUGH THE DAY. MAX TEMPS WILL STILL BE BELOW
NORMAL…WITH LOW TO MID 20S FOR VALLEY AREAS /TEENS IN THE HIGH
TERRAIN/.

TONIGHT…SKIES WILL CLEAR OUT AS THE THE DISTURBANCE MOVES EAST OF
THE REGION. THERE STILL MAY BE A BREEZE IN THE EVENING…BUT WINDS
SHOULD START TO BECOME LIGHT BY AFTER MIDNIGHT. WITH THE CLEARING
SKIES AND FRESH SNOW PACK IN PLACE…HAVE GONE COOLER THAN MOS
GUIDANCE FOR MIN TEMPS…WITH SINGLE DIGITS FOR MOST AREAS. SOME
BELOW ZERO READINGS WILL OCCUR IN THE ADIRONDACKS…GLENS FALLS
AREA…AND SOUTHERN VT.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/…
GENERAL MODEL SUITE AGREEMENT DURING THIS PERIOD AMONG THE GFS/NAM/GEM/
WITH THE GEM/12UTC ECMWF BEING DRIER WITH VERY LITTLE QPF.

AT 500HPA MUCH OF THE EASTERN USA IS IN FAST W-NW FLOW WITH
SHORT WVS RACING ACROSS RGN. INITIALLY WEAK SFC HIGH PRESSURE IS
OVER RGN. AIR MASS OVER RGN IS MOISTURE STARVED.

AT SFC A SERIES OF CDFNTS MOVE THROUGH DURING THE PERIOD. THE
FIRST SAT NT INTO SUN RESULTS IN INCRG CLOUDS AND SOME -SN AND
ENHANCED LAKE EFFECT -SNSH INTO TUG HILL. BUT NOT MUCH IN THE WAY
OF ACCUMULATION. ANOTHER CDFNT 500HPA SHORT WV PAIR DROP SLOWLY
SOUTH THROUGH RGN MONDAY. AGAIN NOT MUCH MORE THAN -SHSN WITH
MAYBE A MODEST ENHANCEMENT BY LK ONTARIO AS IT MOVES THROUGH ON
290-300 VECTORS.

HIGH PRESSURE BUILDS S IN ITS WAKE INTO RGN MONDAY NIGHT. OVERALL
TEMPS DURING THIS PERIOD WILL BE 5-10 DEG BLO NORMALS.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/…
DURING THIS PERIOD FAST 500HPA FLOW SHIFTS FM NW TO W THEN SW AS
SHRTS WV DIG A TROF OVER THE E USA THU. AT SFC HIGH PRESSURE WILL
REMAIN IN PLACE THROUGH WED AND SLIDES OFFSHORE WED NT.

THE FIRST TWO DAYS ALL THE GUIDANCE (GFS/ECMWF/HPC)IS IN AGREEMENT. THURSDAY
AGREEMENT GOES OUT THE WINDOW AS DIVERGE REIGNS.

TUES THE LAST 500HPA SHORT WV IN THE NW FLOW PASSES ACROSS RGN
WITH GFS MAINLY FAIR AND ECMWF SUG MORE CLOUDINESS AND SCT -SHSN.
HIGH PRESSURE LINGERS AT THE SFC INTO WED EVNG. STILL A TRANQUIL
MAINLY DRY PERIOD THROUGH WED NT.

THU WHILE ALL THE MDLS CARVE OUT OR BRING A SIGNIFICANT 500HPA
TROF INTO THE NORTHEAST. WHAT HAPPENS AT THE SFC IS VERY DIFFERENT
BTWN THEM.

OPERATIONAL GFS/GEM KEEP N BRANCH AND S BRANCH DYNAMICS SEPARATE.
GEM PASSES CSTL LOW WELL S OF RGN AND OUT TO SEA. THE GFS DEVELOPS COASTAL
LOW WELL OFF SHORE…OVER AND EAST OF GULF STREAM…WITH AND ONLY
THE 500HPA SHORT WV AND ITS MODEST CLIPPER IMPACTING THE RGN WITH
SOME -SHSN MUCH LIKE THE SYSTEMS WE`VE BEEN HAVING MOST OF THE
WEEK.

HWVR THE OPERATIONAL RUN OF THE GFS IS AMONG THE 10 OR SO IN
ITS OWN ENSEMBLE THAT LEAN TWRD THIS SCENARIO. ITS OTHER 10
MEMBERS HAVE 0.4 TO 1.4 IN QPF MUCH LIKE THE ECMWF DESCRIBED BLO.

THE ECMWF DEVELOPS THE CSTL LOW OVER THE VA CAPES WED NT…AND
SENDS IT NE TWRD BOS THU NT…RIGHT INSIDE THE BENCHMARK…AND
IMPLYING A SIGNIFICANT SNOW EVENT FOR THE FCA WITH 0.50-0.60 QPF
ACROSS FCA. OVERNIGHT HPC GUID ALSO LEANS TWRD ECMWF SOLTN…BUT
NOT TOTALLY.

THE MDL DIFFERENCES SEEM TIED AS USUAL TO HOW AND WHERE THE
RESPECTIVE MODELS PHASE VARIOUS 500HPA SHORT WVS INTO THE EASTERN
TROF ON THU. WHILE THERE REMAINS MUCH UNCERTAINTY AS TO THE
EVENT 6 DAYS OUT…THERE`S AN INCREASING SIGNAL IN THE GUID AT
THIS POINT. TEMPS WILL BEGIN THIS PERIOD WELL BLOW NORMALS AND
END NR TO SLIGHTLY ABV NORMALS. AS SUCH WILL POPULATE WITH HPC
ATTM.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/…
VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS THROUGH THE DAY TODAY
AND INTO TONIGHT.

SCT-BKN STRATOCU AND MID LEVEL CLOUDS WILL MOVE IN THROUGH THE
MORNING HOURS AND CONTINUE INTO THE AFTERNOON THANKS TO A PASSING
UPPER LEVEL DISTURBANCE MOVING ACROSS THE REGION. LITTLE MOISTURE
IS ASSOCIATED WITH THIS FEATURE…SO ONLY SOME FLURRIES ARE EXPECTED.
LIGHT WINDS WILL BECOME WESTERLY BY AROUND 5-10 KTS THIS MORNING.
THERE MAY BE A FEW HIGHER GUSTS AT KALB/KPSF. WINDS WILL DIMINISH
DURING THE EVENING…AND CLOUDS WILL BEGIN TO DECREASE AS THE
DISTURBANCE MOVES EASTWARD. MOST SITES LOOK TO BE NEARLY CLEAR BY
THE LATE EVENING HOURS AND THIS WILL CONTINUE THROUGH THE ENTIRE
OVERNIGHT.

OUTLOOK…
SATURDAY NIGHT/SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SUNDAY NIGHT/MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY NIGHT TO WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT WEEK AS IT WILL BE
DRY OR ANY PRECIPITATION THAT FALLS WILL BE SNOW.

EXPECTING DRY CONDITIONS EXPECTED THROUGH SATURDAY…EXCEPT FOR
SOME LAKE EFFECT SNOW SHOWERS OVER THE WESTERN ADIRONDACKS.

THERE IS A CHANCE FOR MAINLY LIGHT SNOWFALL ACROSS THE REGION
SATURDAY NIGHT INTO MONDAY. A STORM MAY MOVE UP THE EAST COAST
THURSDAY WITH THE POTENTIAL FOR SNOWFALL. ITS TRACK REMAINS HIGHLY
UNCERTAIN AT THIS TIME.

WITH TEMPERATURES EXPECTED TO BE BELOW NORMAL FOR THE NEXT SEVERAL
DAYS…ICE WILL THICKEN ON BODIES OF WATER.

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/SNYDER
NEAR TERM…IAA/FRUGIS
SHORT TERM…SNYDER
LONG TERM…SNYDER
AVIATION…IAA/FRUGIS
HYDROLOGY…SNYDER

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