FXUS61 KAKQ 220809
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
309 AM EST TUE DEC 22 2009
.SYNOPSIS...
WEAK HIGH PRESSURE RETURNS TO THE MID ATLANTIC REGION...AND WILL
DOMINATE OVER THE REGION 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 SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANALYSIS AS OF 3 AM THIS MORNING SHOWS A SURFACE RIDGE BUILDING
SOUTHEAST ACROSS THE MID ATLANTIC...AND A FLAT UPPER LOW ACROSS THE
NORTHERN GREAT LAKES REGION MOVING SOUTHEAST TO NEW ENGLAND BY
WEDNESDAY MORNING. MID TO UPPER LEVEL MOISTURE INCREASES OVER THE
FORECAST AREA WITH THIS FEATURE LATER THIS MORNING THROUGH THIS
AFTERNOON AND SKIES SHOULD BECOME MOSTLY CLOUDY OVER THE NORTHWEST
TIER OF THE AREA WHILE THE REST OF THE AREA SHOULD REMAIN PARTLY
SUNNY. SURFACE RIDGE BUILDING DOWN OVER THE REGION WILL REINFORCE
NORTHERLY FLOW AND COOLER CONDITIONS FOR THE NEXT FEW DAYS. BASED ON
TRENDS PAST 2 DAYS THINK A BLEND OF MET/MAV MOS IS CONSISTENT TO
YIELD HIGHS RANGING FROM UPR 30S NW MID 40S SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WED/THU CHARACTERIZED BY CONTINUED COLD TEMPERATURES AS STRONG
SURFACE HIGH PRESSURE BECOMES CENTERED NORTH OF THE GREAT LAKES WITH
A RIDGE AXIS AND ASSOCIATED LOW LEVEL COLD AIR DAMMING BECOMING
ENTRENCHED DOWN THE ATLANTIC SEABOARD. HIGH TEMPERATURES VERY
SIMILAR DURING THE SHORT TERM (UPPER 30S/40S) WITH INTERMITTENT MID
TO UPPER LEVEL CLOUDINESS. LOWS NEAR 20 NW TO AROUND 30 SE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS ARE CLOSE NOW IN SOLUTIONS WITH MAIN LOW MOVING UP WELL TO
THE W OF THE AREA ON CHRISTMAS DAY. TELECONNECTIONS SUPPORT THE LOW
MOVING WELL WEST OF THE APPALACHIANS. WITH HIGH PRESSURE RIDGING
SOUTH FROM NEW ENGLAND WILL HAVE SOME FORM OF COLD AIR DAMMING OVER
THE SNOW PACK ESPECIALLY ON CHRISTMAS DAY. NOT EXPECTING A LOT OF
PRECIP. MAIN ISSUE WILL BE PRECIP TYPE UNTIL ENOUGH WARM AIR ARRIVES
TO CHANGE ALL PRECIP TO RN. WILL GIVE SOME FREEZING RAIN ON
CHRISTMAS EVE NIGHT INTO CHRISTMAS MORNING STARTING OVER THE SNOW
PACK AREA AND GRADUALLY DIMINISHING TO THE NORTHWEST UNTIL ALL TEMPS
ABOVE FREEZING DURING CHRISTMAS MORNING. THIS LOOKS REASONABLE WITH
ECMWF AND GFS. WILL SEE SOME WARM UP AHEAD OF COLD FRONT WHICH
CROSSES THE AREA ON SATURDAY. THEN DRY AND COLD WITH TEMPS A LITTLE
BELOW NORMAL THROUGH MONDAY. THIS LOOKS SIMILAR ON ALL GUIDANCE.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
QUIET CONDITIONS CONTINUE FOR THE NEXT SEVERAL DAYS...WINDS BECOME
FAIRLY LIGHT/5-10 KT OR LESS AS HIGH PRESSURE BUILDS ACROSS THE
REGION (AT SBY WINDS WILL BE A LITTLE HIGHER/ MORE LIKE 10-15 KT).
EXPECT SOME MID LEVEL CLOUDINESS LATER TODAY BUT ANY CIGS WILL BE
5000 FT OR HIGHER. NEXT POTENTIAL FOR WIDESPREAD LOWER CIGS/VSBYS
WILL COME FRI/CHRISTMAS DAY W/ NEXT SYSTEM.
&&
.MARINE...
NW WINDS WILL PREVAIL FOR THE NEXT 2 DAYS...STILL FAIRLY STRONG ACRS
THE NORTHERN COASTAL WATERS (SUSTAINED 20-25KT)...SO HAVE EXTENDED
THE SMALL CRAFT HEADLINES THROUGH 7 AM. ELSEWHERE...CONDITIONS LOOK
TO REMAIN JUST BELOW CRITERIA.
IN THE EXTENDED...NW TO N FLOW CONTINUES THROUGH LATE THU...AND
WINDS WILL CONTINUE TO BE CLOSE TO/A LITTLE BELOW SMALL CRAFT ADVSY
LEVELS...WITH ADDITIONAL HEADLINES POSSIBLY BEING NEEDED FOR
INTERMITTENT COLD SURGES. WINDS TURN MORE TO THE NE THU
NIGHT/FRI...AND LIKELY INCREASE IN SPEEDS WITH THE NEXT SYSTEM LATER
FRI INTO SAT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR ANZ650-
652.
&&
$$
SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM...JAB
AVIATION...LKB
MARINE...LKB
