FXUS61 KBGM 151152
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
652 AM EST TUE DEC 15 2009
.SYNOPSIS...
A COLD FRONT WILL TRACK SOUTHEAST ACROSS THE AREA TODAY...
ACCOMPANIED BY SCATTERED RAIN SHOWERS...WHICH COULD CHANGE TO
SNOW SHOWERS DURING THE AFTERNOON ACROSS NEW YORK. COLDER WEATHER
WILL FOLLOW BEHIND THE FRONT TUESDAY NIGHT AND WEDNESDAY WITH SOME
LAKE EFFECT SNOW SHOWERS... ESPECIALLY SOUTHEAST OF LAKE ONTARIO.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR IMAGERY SHOWING THE CWA
COVERED WITH LOW LEVEL CLOUDS. THERE HAS BEEN A FEW BREAKS THROUGH
THE NIGHT...WHICH HAS ALLOWED SOME LIGHT FOG TO FORM...MAINLY IN
THE WESTERN PORTION OF THE CWA. RADAR IS SHOWING SOME ISOLATED
LIGHT RAIN SHOWERS MOVING ACROSS THE CWA ATTM. THIS ACTIVITY IS
EXPECTED TO INCREASE THROUGH THE DAY TODAY AS A COLD FRONT
APPROACHES THE AREA AND SLOWLY MOVES ACROSS THE CWA. TEMPERATURES
LOOK TO SUPPORT A RAIN EVENT TODAY...WITH A CHANGE OVER TO SNOW
SOMETIME DURING THE MID AFTERNOON.
COLD AIR WILL FILTER IN BEHIND THE FRONT THIS EVENING. THIS WILL
ALLOW LAKE EFFECT SNOW TO DEVELOP EARLY THIS EVENING.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
FORECASTING THE LOCATION AND INTENSITY OF LAKE EFFECT SNOW WILL BE
THE MAIN FORECAST CHALLENGE FROM TONIGHT THROUGH THURSDAY. BOTH
THE NAM AND GFS INDICATE THAT A WEAK SFC TROUGH WILL PASS SOUTH
ACROSS CENTRAL NY AND NORTHERN PA BY THIS EVENING... ASSOCIATED WITH
A BAND OF LAKE ENHANCED SNOW SHOWERS. THE FLOW BEHIND THIS TROUGH
WILL BE FROM 320 TO 330 DEGREES WHICH WILL BRING ADDITIONAL SNOW
SHOWERS SOUTHEAST FROM LAKE ONTARIO ACROSS THE EASTERN FINGER
LAKES TO THE WESTERN MOHAWK VALLEY. THERE IS SOME QUESTION AS TO
THE EXACT LOCATION OF THE HEAVIER BANDS. HOWEVER...LOOKING AT THE
700MB OMEGA VALUES AND 500MB PVA...IT LOOKS TO SETUP JUST TO THE
WEST OF SYRACUSE. THESE SNOW SHOWERS COULD ACCUMULATE 2 TO 4 IN
MANY PLACES AND COULD RESULT IN SLICK ROADWAYS AS TEMPERATURES
FALL FROM MILD AFTERNOON LEVELS.
NAM SIMULATED REFLECTIVITY AND HISTORICAL ANALOGS BASED ON THE
EXPECTED FLOW PATTERN INDICATES THAT MULTI-BAND SNOW SHOWERS WILL
SHIFT TO THE NORTH ON WEDNESDAY... WITH THE BIGGEST CONCENTRATION
OF SNOW SHOWERS PROBABLY SETTING UP NEAR THE SYRACUSE CORRIDOR FOR
AWHILE WITH A FLOW FROM 290 TO 300 DEGREES. THESE SHOWERS COULD
PRODUCE LOCALIZED 2 TO 4 INCH AMOUNTS. ANOTHER TROUGH IS THEN
FORECAST TO DROP SOUTH ACROSS THE AREA WEDNESDAY NIGHT... POSSIBLY
PUSHING THE SNOW SHOWERS BACK TO THE SOUTH FOR AWHILE. SNOW
SHOWERS WILL BE DIMINISHING ON THURSDAY AS HIGH PRESSURE BUILDS
IN.
TOTAL SNOW ACCUMULATIONS FROM THE MULTI-BAND LES TUESDAY NIGHT
INTO THURSDAY SHOULD REMAIN BELOW WARNING THRESHOLDS ACROSS THE
AREA AS NONE OF THE BANDS WILL BE AS INTENSE AS WHAT WAS SEEN LATE
LAST WEEK... PLUS THE FACT THAT THEY WILL BE SHIFTING. HOWEVER...
UP TO 5 OR 6 INCHES COULD ACCUMULATE TUESDAY NIGHT INTO THURSDAY
OVER THE HIGHER TERRAIN SOUTH OF SYRACUSE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CONTINUED COOL (SLIGHTLY BELOW NORMAL) WX IS EXPECTED THROUGH THE
CONCLUSION OF THE FORECAST PERIOD AS THE REGION REMAINS UNDER THE
INFLUENCE OF STAGNANT POLAR LOW THAT WILL BE SPINNING ACROSS THE
CANADIAN MARITIME. WITH TIME AS THE WEEKEND APPROACHES...WESTWARD
EXTENSION OF SAID UPPER LOW WILL CREATE ANOTHER POLAR VORTEX JUST
SOUTH OF HUDSON BAY. ALONG THE SURFACE...BUILDING HIGH PRESSURE
WILL EXTEND INTO THE AREA BY FRI IN THE FORM OF A WELL DEVELOPED
SURFACE RIDGE AXIS. THIS FEATURE WILL ACT TO KEEP COOL CANADIAN
AIR TRAPPED ACROSS THE AREA. QUICK LOOK AT H85 TEMPS YIELD VALUES
IN THE -11 TO -13C RANGE WHICH SUPPORTS HIGHS IN THE MID TO UPPER
20S REGION WIDE. MODEL AGREEMENT IS FAIRLY DECENT THROUGH THE
BEGINNING PORTIONS OF THE EXTENDED PERIOD WITH ALL GUIDANCE
(ECMWF/GFS/GEM) INDICATING THE DEVELOPMENT OF A COASTAL LOW BY
LATE WEEKEND OFF THE DELMARVA PENINSULA AS A DISTURBANCE IN THE
SOUTHERN STREAM APPROACHES THE EAST COAST. ALL GUIDANCE AS OF THIS
POINT TAKES THE FEATURE NORTHEAST AND OUT TO SEA...THUS ONLY
PROVIDING MINIMAL IMPACTS ACROSS THE FORECAST AREA. FOR NOW HAVE
BUMPED UP POPS SUN NIGHT/EARLY MON IN ANTICIPATION OF THIS
FEATURE. AS FOR THE REMAINDER OF THE EXTENDED...ONLY MADE MINOR
CHANGES TO POPS/TEMPS. LOOKS LIKE COLD AIR WILL BE LOCKED INTO
PLACE THROUGH THE BEGINNING PORTIONS OF THE WEEKEND AND HAVE TRIMMED
TEMPS ACCORDINGLY. NO REAL MAJOR WX MAKERS IN SIGHT FOR THE TIME
BEING...WITH ONLY LIGHT SNOW SHOWERS POSSIBLE ACROSS LAKE EFFECT
PRONE LOCATIONS (LAKE ONTARIO PLAIN) FOLLOWING THE COASTAL LOW/S
DEPARTURE.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
FAIRLY CONSISTENT THINKING FROM THE 06Z UPDATE AS RESTRICTIONS WILL
PLAGUE AREA TERMINALS TODAY IN THE FORM OF LOW CIGS/VSBYS TODAY. COLD
FRONT NOW WORKING THROUGH THE MAJORITY OF THE REGION WHICH IS
LEADING TO LIGHT -RA ACROSS SEVERAL LOCATIONS EARLY THIS MORNING.
FEATURE WILL CONTINUE MOVING OFF TO THE EAST...WITH BROAD
NORTHWESTERLY FLOW EXPECTED TO SET UP IN ITS WAKE. ORIGINALLY
THOUGHT THAT GUSTY WINDS WOULD BE AROUND THE AREA THIS AFTERNOON
HOWEVER DECIDED TO BACK OFF ON MENTION BASED ON WEAK PRESSURE
RISES WHICH IS EVIDENT ON LATEST 11Z MSAS ANALYSIS. IN ANY
EVENT...LATEST 11-3.9U SATELLITE IMAGERY SHOWING LOW CLOUDS
BEGINNING TO ENTER THE AREA FROM THE WEST AS A NOTABLE COLD AIR
ADVECTION REGIME BEGINS TO TAKE SHAPE. MVFR CIGS/VSBYS WILL BE
AROUND FOR MUCH OF THE DAY...WITH SCATTERED -RASN POSSIBLY MIXING
IN AT TIMES AS COLD AIR BEGINS TO FILTER OVER THE WARM WATERS OF
LAKE ONTARIO. BY TONIGHT...MAIN TROUGH AXIS NOW LOCATED ACROSS
WESTERN LAKE SUPERIOR WILL SWING THROUGH THE AREA BRINGING A
WIDESPREAD SNOWFALL TO MUCH OF THE REGION. IN ITS WAKE...VERY COOL
TEMPS ALOFT WILL WORK INTO THE REGION WHICH WILL SET THE STAGE
FOR LAKE EFFECT SNOW SHOWERS ACROSS THE KITH/KRME/KSYR. AS OF
NOW...IT LOOKS AS IF KSYR/KITH WILL HAVE THE GREATEST IMPACT FROM
THIS ACTIVITY AS WINDS BACK TOWARDS A MORE NORTHWESTERLY 310-320
FLOW.
.OUTLOOK...
WED THRU SAT...AREAS OF MVFR ACRS CNTRL NY IN LES. GNRLY VFR AT
AVP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...10
NEAR TERM...10
SHORT TERM...10
LONG TERM...CMG
AVIATION...CMG
