FXUS61 KAKQ 230834
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
334 AM EST WED DEC 23 2009
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGED ALONG THE EAST COAST THROUGH
CHRISTMAS EVE. A WARM FRONT...ASSOCIATED WITH A STRONG LOW
PRESSURE OVER THE MID MISSISSIPPI RIVER VALLEY...WILL SWING
THROUGH THE MID ATLANTIC REGION CHRISTMAS DAY...AND WILL BE
FOLLOWED BY A COLD FRONT THAT WILL MOVE THROUGH THE AREA BY
SATURDAY MORNING. HIGH PRESSURE BUILDS BACK INTO THE REGION FROM
THE WEST SATURDAY AFTERNOON INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANALYSIS AS OF 3 AM THIS MORNING SHOWS STRONG SURFACE HIGH PRESSURE
BECOMING CENTERED AT A POSITION JUST NORTH OF THE GREAT LAKES. THE
RIDGE AND ASSOCIATED LOW LEVEL COLD AIR DAMMING REMAINS ENTRENCHED
DOWN THE ATLANTIC SEABOARD. ELSEWHERE... A FRONTAL BOUNDARY IS
DEVELOPING TO OUR NORTHWEST OVER THE MOUNTAINS AND SHORT TERM MODELS
SHOW THAT IT WILL CROSS THE FORECAST AREA TODAY. THERE IS LITTLE
MOISTURE WITH THIS FEATURE...ONLY MID TO HIGH LEVEL CLOUD COVER CAN
BE EXPECTED AS IT SHIFTS THROUGH. CLOUDS TODAY...WHILE NOT
COMPLETELY OVERCAST...WILL PUT A DAMPER ON HIGH TEMPERATURES. (UPPER
30S FAR NORTH TO UPPER 40S SE.)
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
UNDER NORTH/NORTHWEST FLOW SEASONABLY CHILLY CONDITIONS WILL
CONTINUE THROUGH TONIGHT AND CHRISTMAS EVE.
ATTENTION THEN TURNS TO THURSDAY NIGHT AND CHRISTMAS. MODELS ARE IN
EXCELLANT AGREEMENT...THOUGH THEY CONTINUE TO SLOW DOWN THE TIMING
OF OUR NEXT SYSTEM. AS DEEPENING SURFACE LOW PRESSURE PIVOTS
NORTHWARD THROUGH THE MS VALLEY THU/FRI...THIS WILL LIFT A WARM
FRONT ACROSS THE FORECAST AREA FRIDAY MORNING. THICKNESS'S WARM
CONSIDERABLY DURING THIS TIME PERIOD...ALBEIT 1000-850 MB REMAIN
SOMEWHAT BORDERLINE AROUND 1310-1320 M ACROSS NW VA THU NIGHT INTO
EARLY FRI MORNING. CONSIDERING THIS...AND THE FACT THAT SURFACE
TEMPERATURES WILL BE IN THE UPPER 20S...FREEZING RAIN IS POSSIBLE
AFTER MIDNIGHT CHRISTMAS EVE...POSSIBLY MIXING WITH A LITTLE SLEET
AT THE ONSET OF THE EVENT. AREA CONCERNED IS MAINLY THE PIEDMONT.
BASED ON GOOD MODEL CONSISTENCY...HAVE LEFT FREEZING RAIN IN THE
FORECAST FOR CHRISTMAS MORNING. ALL PRECIPITATION SHOULD TRANSITION
TO RAIN BY LATE IN THE MORNING. QPF AT THIS TIME DOES NOT LOOK
SIGNIFICANT...LESS THEN A TENTH OF AN INCH...AND AS TEMPERATURES
WARM THROUGHOUT CHRISTMAS MORNING WOULD EXPECT THE IMPACT TO BE
MINIMAL. WILL CONTINUE TO HIGHLIGHT THE THREAT FOR FREEZING RAIN IN
THE HWO.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CENTER OF VIGOROUS UPR LVL SYSTEM IMPACTING THE MIDWEST MID-LATE
THIS WEEK WILL CONTINUE TO ROTATE OVER THE GRT LKS RGN INTO THE
WKND. DRY SLOT FILTERS INTO THE AREA FROM THE SW AS ASSCD FRONTAL
SYSTEM SLIDES OFFSHORE FRI NIGHT/ERLY SAT. LOOK FOR TEMPS TO FALL
BLO NRML INTO ERLY NEXT WEEK AS ANOTHER SURGE OF COOLER AIR FILTERS
INTO THE RGN WITH UPR LVL LOW. COULD SEE SOME SCT -SN/FLY'S OVER THE
FAR N/NE MON NIGHT/TUE IF ANY LAKE EFFECT STREAMERS CAN BE
ESTABLISHED OFF THE GRT LKS...BUT HELD OFF IN FCST FOR NOW.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
QUIET CONDITIONS CONTINUE TODAY AND THURSDAY...FAIRLY LIGHT WINDS OF
5-10 KT OR LESS OVERALL AND VARIABLY CLOUDY SKIES (ANY CIGS WILL BE
OF THE VFR VARIETY >3000 FT.
NEXT POTENTIAL FOR WIDESPREAD LOWER CIGS/VSBYS WILL COME BY EARLY
FRI/CHRISTMAS DAY W/ NEXT SYSTEM. DECENT CHANCE FOR RAIN...WITH
MIXED PRECIPITATION INITIALLY POSSIBLE FOR RIC EARLY IN THE MORNING.
ALSO COULD SEE BREEZY CONDITIONS ALONG THE COAST/ECG-ORF LATER FRI
INTO SAT. OTHERWISE...IMPROVING CONDS LATER SAT AND THEREAFTER.
&&
.MARINE...
NO FLAGS...NNW TO NNE WINDS WILL PREVAIL TODAY...BECMG NNE OR NE ON
THU. A FEW BRIEF INCREASES IN WIND SPEEDS CAN BE EXPECTED WITH MINOR
COLD SURGES...BUT EXPECT CONDITIONS TO REMAIN BELOW SMALL CRAFT
ADVSY CRITERIA.
FRI/SAT...WITH SFC LOW APPRCHG FROM THE SW AND HIGH PRESSURE ACRS
ERN CANADA/NRN NEW ENGLAND...EXPECT A SIGNIFICANT INCREASE IN WINDS
WITH AN ENE DIRECTION DEVELOPING BY FRI MORNING...GRADUALLY VEERING
TO ESE ON SAT. SEAS LOOK TO BUILD TO AT LEAST 6-8 FT (POSSIBLY
HIGHER DEPENDING ON DURATION OF THE EVENT). SYSTEM MOVES OFF TO THE
NORTH ON SAT...EVENTUALLY BRINGING A COLD FRONT THROUGH ALONG WITH
OFFSHORE WNW FLOW LATER SAT INTO SUNDAY.
&&
.CLIMATE...
COULD IT BE A WHITE CHRISTMAS AT RICHMOND? OFFICIALLY...A "WHITE
CHRISTMAS" IS DEFINED AS HAVING A SNOW DEPTH OF 1" OR MORE ON THE
GROUND (CURRENT DEPTH REPORTED AT RIC IS 3"). WITH 2 DAYS TO
GO...AND FAIRLY COLD TEMPERATURES CONTINUING THERE IS A DECENT
CHANCE THAT THERE WILL STILL BE AT LEAST 1" ON THE GROUND. RECORDS
HAVE BEEN KEPT AT RICHMOND SINCE 1897...MAKING FOR A 113 YEAR PERIOD
INCLUDING THIS YEAR. OF THESE 113 CHRISTMAS'...ONLY 8 HAVE HAD 1" OR
MORE ON THE GROUND (A 7% CHANCE).
&&
.EQUIPMENT...
DUE TO PHONE LINE PROBLEMS...ALL NOAA ALL HAZARDS/WEATHER RADIO
TRANSMITTERS OPERATING OUT OF WFO WAKEFIELD VA ARE DOWN UNTIL
FURTHER NOTICE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM...CCW
AVIATION...LKB
MARINE...LKB
EQUIPMENT...AKQ
