670
FXUS61 KBGM 210750
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
250 AM EST SAT NOV 21 2009
SYNOPSIS
A MOIST NORTHWESTERLY FLOW OF AIR WILL KEEP OUR SKIES CLOUDY TODAY
WITH HIGH TEMPERATURES EITHER SIDE OF 50. BY THE 2ND HALF OF THE
WEEKEND AN AREA OF HIGH PRESSURE NOW LOCATED OVER THE OHIO VALLEY
WILL BUILD OVERHEAD HELPING TO CLEAR OUT THE CLOUDS MAKING FOR A
VERY BRIGHT END TO THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 250 AM...MOSTLY CLOUDY SKIES CONTINUE ACROSS THE AREA AT THE
MOMENT WITH DRY WEATHER. DESPITE A NORTHWEST FLOW OVER THE LAKES
WITH 850 TEMPS AROUND +2C/3C WE ARE JUST NOT COLD ENOUGH FOR LAKE
EFFECT ACTIVITY. A SHORTWAVE THAT IS NOW MOVING THROUGH LOWER
MICHIGAN INTO SOUTHERN ONTARIO WILL TRACK EAST THIS MORNING. GIVEN
THAT RADAR IMAGERY TO OUR WEST SHOWS NOTHING I AM NOT EXPECTING
ANY PRECIPITATION TODAY. FOR THE REST OF TODAY OUR AREA WILL BE
STUCK WITH A VERY SHALLOW LAYER OF STRATO-CU BASED ON BOTH THE NAM
AND GFS. BOTH MODELS SHOW GREATER THAN 90% RH FROM JUST ABOVE THE
SURFACE UP THROUGH ABOUT 3KFT. IT CERTAINLY IS A VERY SHALLOW
LAYER AS YOU DON'T HAVE TO GO MUCH ABOVE THAT TO FIND AN ABSENCE
OF MOISTURE. WHILE A PEEK OR TWO OF SUN IS POSSIBLE LATE IN THE
DAY ALMOST ANYWHERE THIS SEEMS TO BE ABOUT THE EXTENT OF ANY HOPE
FOR SUN. THE LONE EXCEPTION MAY BE ACROSS THE FAR SOUTHEAST WHERE
CLIMATOLOGY FAVORS A SLIGHTLY BETTER CHANCE FOR A FEW SUNNY
BREAKS. 925 TEMPS AROUND 2/3 C SUPPORT HIGHS NEAR 50...WITH
SLIGHTLY WARMER 925S NEAR KELM SUPPORTING HIGHS IN THAT AREA
CLOSER TO 53.
THE OFTEN MOISTURE LADEN NAM KEEPS IN MOISTURE THROUGH TONIGHT
WHILE THE GFS SEEMS TO HAVE A BETTER IDEA BY THINNING OUT THE DECK
OF CLOUDS GRADUALLY. THE KEY WORD TONIGHT WILL BE GRADUALLY AS
EVEN THE MORE OPTIMISTIC GFS DOES NOT SHOW DRYING BELOW THE
INVERSION UNTIL AFTER 06Z.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
AS OF 250 AM...SUNDAY WILL BE THE PAY OFF DAY OF THE WEEKEND WITH A
SURFACE HIGH PRESSURE SYSTEM BUILDING RIGHT OVERHEAD. ANY
LINGERING CLOUDS FROM THE OVERNIGHT WILL QUICKLY BE A DISTANT
MEMORY WITH A SUN FILLED DAY. WHILE ABUNDANT SUNSHINE IS EXPECTED
BOTH THE NAM AND GFS SHOW US BARELY MIXING TO 925 MB AND WITH HP
IN CONTROL WINDS WILL BE VERY LIGHT. ADDING TO THE TEMP FORECAST
PROBLEM SUNDAY IS THE FACT THAT THE GFS AND NAM ARE ABOUT 3C APART
ON 925 MB TEMP FORECASTS. THE GFS WITH 925S AROUND 5 OR 6 IS
SUGGESTIVE OF HIGHS IN THE MIDDLE 50S WHILE THE NAM IS CLOSER TO
50 AGAIN WITH 925S AROUND 3. I SPLIT THE DIFFERENCE FOR NOW BUT MY
GUT SAYS DESPITE THE SUNSHINE THE COOLER MET GUIDANCE WILL BE MORE
ACCURATE GIVEN THE LIMITED MIXING POTENTIAL (LIGHT WINDS, LOW
INVERSION).
FORECAST PROBLEMS BEGIN BY MONDAY AS THE MODELS ARE HAVING TROUBLE
TRYING TO RESOLVE THE 500 TROF NOW OVER SOUTHEAST TX. THE GFS
SEEMS TO BE THE OUTLIER IN BRINGING IN MOISTURE ON
MONDAY...BY KEEPING THE 500 TROF MUCH STRONGER. THE OTHER
MODELS...ESPECIALLY THE GEM AND NAM KEEP THE 500 TROF MORE OF AN
OPEN WAVE AND FOCUS MORE ON THE POTENTIAL COASTAL DEVELOPMENT OFF
THE DELMARVA. THIS WOULD KEEP THE BULK OF THE MOISTURE TO OUR
EAST THROUGH MONDAY EVENING. A BLEND BETWEEN THE NAM AND GEM WAS
USED WITH SOME SHOWERS POSSIBLE LATE IN THE DAY FROM NEPA UP
THROUGH THE CATSKILLS. THE NEW EURO IS IN AND SEEMS TO BE A
COMPROMISE BETWEEN THE GFS CAMP AND THE GEM/NAM KEEP BY KEEPING
THE WAVE MORE OPEN (LIKE THE NAM/GEM MODELS) BUT STILL SHOWING
SOME MOISTURE IN OUR AREA. OVERALL THE IDEA REMAINS THE
SAME...BEST CHANCES FOR MOISTURE WILL BE THE FARTHER SOUTH/EAST
YOU GO.
LONG TERM /TUESDAY THROUGH FRIDAY/
UPDATED AS OF 101 AM...NO APPRECIABLE CHANGES TO THE FORECAST THIS
PERIOD.
MODEL CONSENSUS STILL INDICATES THAT THE MAJORITY OF THE RAINFALL
WITH THE SURFACE WAVE OFF THE EAST COAST ON TUESDAY WILL STAY
EAST OF THE FORECAST AREA...SO ONLY SLIGHT CHANCE PROBABILITIES
LOOK GOOD FROM THIS VANTAGE POINT.
THE START OF THE HOLIDAY PERIOD FROM WEDNESDAY THROUGH FRIDAY
STILL CARRIES PLENTY OF FORECAST UNCERTAINTY AT THIS TIME.
OVERALL...LONGER RANGE GUIDANCE IS LEANING TOWARDS A SLOWER ONSET
OF PRECIPITATION (MORE LIKE ON THANKSGIVING DAY OR THANKSGIVING
NIGHT)...WITH WEDNESDAY MAINLY DRY. THE GFS...HOWEVER...IS MUCH
FASTER IN CARRYING ENERGY EASTWARD INTO OUR NECK OF THE WOODS BY
WEDNESDAY...WITH SHOWERS BEGINNING AT THAT POINT. GIVEN ALL THE
MODEL DISCREPANCIES...WON'T TINKER MUCH WITH OUR GOING
FORECAST...WHICH DOES MENTION AT LEAST A LOW CHANCE OF SHOWERS ON
WEDNESDAY. ONE WELL AGREED UPON SCENARIO IS THAT WEDNESDAY AND
THANKSGIVING DAY WILL CONTINUE TO FEATURE MILD TEMPERATURES.
BY FRIDAY...IT APPEARS THAT COLDER AIR WILL BEGIN TO FILTER
IN...AS A STORM SYSTEM WINDS UP OFFSHORE. THIS WOULD LIKELY
RESULT IN SOME LAKE RESPONSE...WITH A GOOD SHOT OF RAIN AND SNOW
SHOWERS.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
AT KSYR...KRME...KITH...AND KBGM...WE'RE LOOKING FOR CEILINGS TO LOWER
INTO THE MVFR CATEGORY TOWARDS DAYBREAK SATURDAY...LASTING THROUGH THE
MID-MORNING HOURS. BY MIDDAY (15-18Z)...VFR SHOULD RETURN AREA-
WIDE...AS SKIES SLOWLY CLEAR AND CLOUD BASES LIFT.
WESTERLY WINDS AROUND 5 KT OVERNIGHT...WILL TURN NORTHWEST AND
INCREASE TO ABOUT 10 KT SATURDAY.
AT KELM AND KAVP...MAINLY VFR ANTICIPATED THROUGH 06Z SUNDAY.
LIGHT WINDS OVERNIGHT AND EARLY SATURDAY...WILL TURN WEST TO
NORTHWEST AROUND 10 KT FOR THE LATE MORNING AND AFTERNOON PERIOD.
OUTLOOK...
SAT NGT...SOME MVFR CIGS PSBL.
SUN/SUN NGT...VFR.
MONDAY/MON NGT...MVFR POSSIBLE IN SHOWERS.
TUESDAY/WEDNESDAY...VFR.
BGM WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NY...NONE.
SYNOPSIS...HEDEN
NEAR TERM..HEDEN
SHORT TERM...HEDEN
LONG TERM...MLJ/RRM
AVIATION...MLJ
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