FXUS61 KBGM 270610
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
110 AM EST FRI NOV 27 2009
.SYNOPSIS...
A STORM SYSTEM WILL BRING RAIN...AND MAYBE SOME HIGHER ELEVATION
WET SNOW...EARLY THIS MORNING INTO TODAY. THE REST OF THE HOLIDAY
WEEKEND WILL FEATURE SEASONABLY CHILLY TEMPERATURES...ALONG WITH A
FEW RAIN AND SNOW SHOWERS ON SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED THIS EVENING...
BASED ON LATEST LAMP DATA AND SFC OB TRENDS BUMPED MIN TEMPS UP
SEVERAL DEGREES AND PUSHED BACK THE POSSIBLE RAIN/SNOW MIX UNTIL
AFTER 08Z. LATEST MODEL SOUNDINGS NAM/RUC WOULD ALSO IMPLY
POSSIBLE RAIN/SNOW MIX ONLY AT THE HIGHER ELEVATIONS PRIMARILY
FROM I81 WEST AND LATE. ALSO LOWERED THE POSSIBLE MINOR SNOW
ACCUMS FOR THE COLDER AREAS. NO OTHER CHANGES.
UPDATED AS OF 3 PM... CLOUDS ARE FILLING IN ONCE AGAIN LATE THIS
AFTERNOON...AS MOISTURE FROM BOTH A COASTAL STORM SYSTEM...AND
UPPER-LEVEL WAVE TO OUR WEST...BEGIN TO CONVERGE ON THE REGION.
MODELS IN FAIR AGREEMENT THAT A NORTH TO SOUTH BAND OF STEADY
PRECIPITATION WILL DEVELOP ACROSS OUR WESTERN ZONES EARLY THIS
EVENING...THEN SLOWLY TRANSLATE EASTWARD OVERNIGHT. LARGE SCALE
ASCENT (NICE Q-VEC FORCING SHOWN ON NAM...GFS...AND SREF
SOLUTIONS) FROM A DIGGING MID TO UPPER-LEVEL WAVE ACROSS THE
EASTERN GREAT LAKES WILL BE THE MAIN PLAYER IN THIS SCENARIO.
THE MAIN ISSUE LATER TONIGHT INTO EARLY FRIDAY SURROUNDS
PRECIPITATION TYPE. COLDER AIR WILL FILTER IN FROM THE WEST OVER
TIME...AND MODEL THERMAL PROFILES SUGGEST A CHANGE OVER TO WET
SNOW ACROSS THE HIGHER TERRAIN BY THE 08Z-12Z TIME
FRAME...PARTICULARLY WEST OF THE I-81 CORRIDOR. EVEN ON THE
HILLTOPS...MARGINAL LOW-LEVEL TEMPERATURES AND QUESTIONABLE
DENDRITE PRODUCTION SHOULD YIELD FAIRLY DENSE CRYSTALS (LESS THAN
10:1 RATIOS). FOR NOW...WE'RE CALLING FOR THE POSSIBILITY OF 1-2"
ACCUMULATIONS ON THE HILLTOPS...AGAIN MAINLY FROM ABOUT I-81
WESTWARD...BY DAYBREAK.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
THE STEADIEST PRECIPITATION ON FRIDAY SHOULD BE DURING THE
MORNING. MODEL FGEN...Q-VEC...AND OMEGA FIELDS ALL SUGGEST A
FAIRLY RAPID TRANSITION OF THE HEAVIEST PRECIPITATION WELL EAST
INTO NEW ENGLAND BY 18Z FRIDAY. A RAIN/SNOW MIX ON THE HILLS AND
MOSTLY RAIN IN THE VALLEYS IS THE FORESEEN PRECIPITATION TYPE ON
FRIDAY. PERHAPS ANOTHER INCH OR SO OF SNOW ACCUMULATION IS
POSSIBLE ON FRIDAY OVER THE HIGHER TERRAIN...WITH LITTLE OR
NOTHING IN THE VALLEYS.
FRIDAY NIGHT AND SATURDAY...SYNOPTIC WRAP-AROUND MOISTURE FROM THE
COASTAL NEW ENGLAND LOW...AND ADDITIONAL LOW-LEVEL MOISTURE FROM
THE GREAT LAKES...WILL LIKELY BRING SOME LAKE-EFFECT/LAKE-ENHANCED
SNOW SHOWERS TO THE REGION. A MEAN 300 DEGREE VECTOR WOULD BRING
MOST OF THESE SNOW SHOWERS INTO ONONDAGA/MADISON/SOUTHERN
ONEIDA/CHENANGO/OTSEGO COUNTIES. ALTHOUGH MOISTURE SUPPLY IS
FAIRLY DEEP...AT LEAST TO START OFF FRIDAY EVENING...THE AIR MASS IS NOT
ALL THAT COLD (LAKE/850 DIFFERENTIALS OF 13-15C)...AND THERE IS
SOME DIRECTIONAL SHEAR IN THE MIXED LAYER. AT THIS POINT...WE'LL
GENERALLY GO WITH 1-3" AMOUNTS IN THE ABOVE MENTIONED
COUNTIES...ESPECIALLY ON THE HILLTOPS.
GUSTY WINDS ARE ALSO EXPECTED THIS PERIOD...AS THE PRESSURE
GRADIENT TIGHTENS. LOW-LEVEL LAPSE RATES/MOMENTUM TRANSFER
PROFILES SUGGEST PERHAPS A FEW GUSTS APPROACHING 40 KT.
ISALLOBARIC FORCING DOESN'T LOOK ESPECIALLY STRONG AT THIS EARLY
VANTAGE POINT...SO THIS SEEMS LIKE A BORDERLINE ADVISORY TYPE SITUATION.
LATER SHIFTS WILL FURTHER ASSESS.
THINGS QUIET DOWN BY SATURDAY NIGHT...AS HIGH PRESSURE BRIEFLY
BUILDS ACROSS THE AREA. ON SUNDAY...AN APPROACHING COLD FRONT
COULD BRING A FEW RAIN SHOWERS BACK TO THE REGION BY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MODELS IN SOMEWHAT OF AGREEMENT FOR THE BEGINNING OF THE EXTENDED
FORECAST PERIOD WITH GENERAL UPPER LEVEL TROUGHINESS EXTENDING
FROM THE GREAT LAKES THROUGH THE PLAINS. BOTH THE ECMWF AND THE
GFS SHOW THIS TROUGH AND A COLD FRONT MOVING THROUGH THE CWA BY
MONDAY AFTERNOON. THIS WILL BRING A CHANCE FOR PRECIPITATION MONDAY
EVENING THROUGH TUESDAY. IT WILL BEGIN S RAIN AND LOOKS TO CHANGE
OVER TO SNOW EARLY TUESDAY MORNING. IT SHOULD THEN GRADUALLY
CHANGE BACK OVER TO RAIN ON TUESDAY AFTERNOON. A RIDGE BUILDS IN
FOR THE MIDDLE OF THE WEEK TO BRING A BRIEF PAUSE TO THE
PRECIPITATION BEFORE IT PICKS UP AGAIN ON THURSDAY. ON
THURSDAY...ANOTHER COLD FRONT WILL MAKES ITS WAY ACROSS THE CWA.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR AND MVFR CONDITIONS WILL FALL TO MVFR AND AT TIMES IFR
CONDITIONS EARLY THIS MORNING. IFR WILL BE MOST LIKELY AT KITH AND
KBGM. STEADY MAINLY LIGHT RAIN HAS MOVED INTO THE TAF SITES AND
WILL END FROM W TO E STARTING AROUND 09Z AT KELM. FOR ALL BUT SYR
AND RME AND ITH CONDITIONS WILL IMPROVE TO VFR IN THE DRY SLOT.
WITH A NW FLOW OFF OF CAYUGA LAKE KITH SHOULD REMAIN MVFR ALL DAY.
FURTHER NORTH NW FLOW OFF OF LAKE ONTARIO WILL ALSO KEEP THEM IN
MVFR CIGS AND A FEW -SHRA. THIS EVENING A SECONDARY COLD FRONT AND
CAA WILL BRING BACK -SH OF RAIN AND SNOW. CONDITIONS WILL WORSEN
BACK TO MVFR AND MAYBE IFR FOR ALL BUT KAVP.
WINDS EARLY THIS MORNING AROUND 5 KTS OUT OF THE W TO NW. WINDS
INCREASE MIDDAY AND AFTN TO 10 TO 15 KTS WITH HIGHER GUSTS.
TONIGHT WITH CAA AND ALIGNED FLOW WINDS WILL REMAIN STRONG AND
GUSTY.
OUTLOOK...
TONIGHT TO SAT...MVFR/IFR RESTRICTIONS IN RAIN/SNOW SHOWERS.
SAT NGT TO SUN...IMPROVEMENT TO VFR.
SUN AFTN TO TUE...MVFR IN RAIN AND SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ/RRM/10
SHORT TERM...MLJ
LONG TERM...10
AVIATION...TAC
