FXUS61 KAKQ 111625
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1125 AM EST THU MAR 11 2010

.SYNOPSIS...
A SLOW MOVING LOW PRESSURE SYSTEM SLIDES INTO THE MID MISSISSIPPI
RIVER VALLEY TODAY...PUSHING ANOTHER WARM FRONT ACROSS THE MID
ATLANTIC STATES LATE TONIGHT. THE COLD FRONT ASSOCIATED WITH THE
SYSTEM CROSSES THE AREA LATE FRIDAY...WITH LOW PRESSURE
DEVELOPING ALONG THE FRONT ON SATURDAY AS IT MOVES TO THE NORTH.
NORTHWEST FLOW RETURNS SUNDAY INTO EARLY NEXT WEEK AS THE LOW
SLOWLY MOVES AWAY FROM THE COAST.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE RADAR IS MAINLY DRY AT THIS TIME...BUT THE RAIN IS
APPROACHING FROM THE SOUTH AND SHOULD ARRIVE LATE IN THE DAY ALONG
THE VA/NC BOARDER AND SPREAD NORTHWARD OVERNIGHT REACHING THE MD
PORTION OF THE DELMARVA AFTER MIDNIGHT. THE BIG QUESTION FOR THIS
AFTERNOON IS CLOUDS. THE SATELLITE SHOWS LOTS OF CLOUDS ACROSS THE
REGION WITH SOME LOW STRATUS STILL HANGING ON AND THE HIGH LEVEL
CIRRUS CONTINUING TO FLOW NORTHWARD AND THICKEN. BUT THERE ARE
BREAKS IN THE CLOUDS TO PEAKS OF SUNSHINE ARE EXPECTED THROUGH OUT
THE DAY. WITH THE CLOUDS EXPECTED TO INCREASE...HAVE NUDGED HIGH
TEMPS DOWN A FEW DEGREES TO THE MID TO UPPER 60S ACROSS THE
REGION. OVERALL THIS LOOKS TO BE THE LAST OF THE DRY WARM DAYS
PRIOR TO A WET COUPLE OF DAYS FRIDAY INTO THE WEEKEND.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
MEANDERING UPR LOW OVER THE MISSOURI VLY CONTINUES TO DOMINATE WX
OVER THE EASTERN CONUS...WITH PRIMARY CHALLENGE IN THE PERIOD
TIMING (NUMEROUS) PCPN OPPORTUNITIES FRIDAY AND SATURDAY.

MODELS ARE IN GENERAL AGREEMENT WITH SYNOPTIC FEATURES AS THE NEXT
SHORTWAVE PUSHES INTO THE REGION. THE GFS IS A HINT FASTER THAN
THE NAM...WHICH IS MORE AGGRESSIVE (AND FARTHER NORTH) WITH
DEVELOPING SFC LOW OVER NC COASTAL PLAIN. STILL...DESPITE THESE
DIFFERENCES...BOTH WOULD BRING DRIER CONDITIONS AND POTENTIALLY
EVEN SOME PARTIAL CLEARING FRI AFTN. THERE IS A LITTLE DRY AIR
BEHIND IT AND WITH THE AREA GOING INTO THE WARM SECTOR...EXPECT TO
SEE SOME BREAKS IN THE CLOUDS AND ALSO A MAINLY DRY
AFTERNOON...ALTHOUGH A SHOWER CAN NOT BE RULED OUT. GIVEN THE
CONTINUED SOUTHERLY FLOW...SHOULD SEE MILD TEMPERATURES ON FRIDAY
SO LEANED TOWARD THE WARMER MAV NUMBERS.

BY FRIDAY NIGHT...THE UPPER LOW WILL BEGIN TO HEAD EAST AND AS IT
DOES THE COLDER AIR WILL FINALLY MOVE EAST...PUSHING THE COLD
FRONT ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES. THE
MODELS ARE DECENT AGREEMENT ON THIS FRONTAL MOVEMENT...BUT WHERE
THE REDEVELOPMENT OF THE SFC LOW TAKES PLACE IS VERY DIFFERENT.
THE NAM CONTINUES TO BE THE OUTLIER DEVELOPING THE LOW OFF THE
COAST. THE FAVORED 00Z/11MAR ECMWF AND GFS BOTH DEVELOP THE LOW
ACROSS THE PIEDMONT OF THE CAROLINAS AND LIFTING ACROSS VA INTO
SRN NJ BY SAT NIGHT. HAVE FOLLOWED CLOSER TO THE TRACK WHICH LEADS
TO SOME SIGNIFICANT RAINFALL FROM LATE FRIDAY NIGHT INTO SATURDAY
WHEN THE LOW AND FRONT PASS THE AREA. THE INCREASING SE FLOW AHEAD
OF THE SYSTEM SHOULD HELP TO FURTHER DEEPEN THE MOISTURE ACROSS
THE REGION. HOWEVER...ONCE THE LOW AND FRONT PASS...THE FLOW TURNS
WESTERLY AND SHOULD HELP TO ONCE AGAIN BEGIN TO DRY OUT THE LOW
AND MID LEVELS.

FOR TEMPERATURES FRIDAY NIGHT THROUGH SATURDAY...CONTINUED TO LEAN
TWDS WARMER ENVELOPE OF GUIDANCE AS THE INCREASED MOISTURE SHOULD
HOLD VALUES UP IN THE UPPER 40S TO LOWER 50S. SATURDAY...TIMING
COULD BE AN ISSUE AS THE LONGER THE CLOUDS AND RAIN HANG AROUND
THE LONGER IT WILL TAKE TO ALLOW FOR THE WARMING. BUMPED HIGHS
UPWARD A BIT IN ANTICIPATION OF SOME DOWNSLOPE-AIDED CLEARING.
THIS COULD ALSO BE A MITIGATING FACTOR FOR CONVECTIVE CHCS SAT
AFTN AS THE UPR LOW CROSSES. WL STICK WITH SLIGHT CHC T WORDING
FOR NOW DURING THE AFTN SATURDAY. HIGHS AGAIN 60S TO L70S.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
GLOBAL OPERATIONAL MODELS AND GFS ENSEMBLES ARE RATHER CONSISTENT 
WITH A LARGE UPPER LOW CENTERED OVER THE MID ATLANTIC AND CENTRAL 
APPALACHIANS SATURDAY NIGHT. AT THIS TIME THE FETCH OF WARM MOIST 
AIR ASSOCIATED WITH THE WARM CONVEYOR BELT IS WELL TO THE NORTH OVER 
NEW ENGLAND. HOWEVER...A SECONDARY SHORTWAVE TROUGH ROUNDS THE BASE 
OF THE UPPER LOW PASSING OVER THE LOCAL AREA LATE SATURDAY NIGHT OR 
SUNDAY MORNING WITH A PERIOD OF RAIN SHOWERS. SYSTEMS SUCH AS THIS 
CAN BE DIFFICULT TO TIME SEVERAL DAYS IN ADVANCE...SO THE EXTENDED 
FORECAST WILL CONTINUE WITH A PERIOD OF CHANCE POPS NORTH...SLIGHT 
CHANCE SOUTH FOR SATURDAY NIGHT AND SUNDAY. THE UPPER LOW SLOWLY 
DRIFTS SOUTH AND SHEARS APART LATE IN THE WEEKEND AND EARLY NEXT 
WEEK BEFORE THE LARGE SCALE UPPER LEVEL FLOW BECOMES NORTHWEST OVER 
THE EAST COAST BY MID WEEK. CONDITIONS SHOULD BE DRY OVERALL AFTER 
SUNDAY WITH THE EXCEPTION OF MONDAY AFTERNOON...WHERE ONE FINAL 
IMPULSE COULD TRIGGER A FEW LIGHT RAIN SHOWERS. TEMPERATURES THROUGH 
THE EXTENDED PERIOD WILL AVERAGE NEAR TO SLIGHTLY ABOVE SEASONAL 
NORMALS.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
ELONGATED BAND OF WARM FRONTAL RAIN (MAINLY LIGHT) CONTINUES TO
LIFT ACROSS THE FORECAST AREA FROM S TO N EARLY THIS MORNING...
EXTENDING MAINLY N OF THE VA/NC BORDER AT SUNRISE. CIGS/VSBYS
HAVE DETERIORATED TO AT LEAST MVFR OVER ALL TERMINALS OUTSIDE OF
THE LWR MD ERN SHORE (INCLUDING SBY)...WITH SCT IFR CONDITIONS.
THIS INITIAL BATCH OF RAIN LIFTS N INTO THE LWR ERN SHORE LATER
IN THE MORNING...WHICH WILL ALSO LEAD TO THE DVLPMNT OF MVFR/
PSBL IFR CONDITIONS OVER SBY BY MIDDAY. ELSEWHERE...AS RAIN TAPERS
LATER THIS AM...EXPECT OCNL MVFR CONDITIONS (MAINLY CIGS) TO
LINGER THROUGH THE AFTN.

A MUCH BROADER AREA OF RAIN WILL THEN DEVELOP FROM S TO N OVER
MOST TAF SITES ONCE AGAIN BY EARLY EVENING (ALL EXCEPT SBY). THE
RESULT WILL BE A LOWERING OF CIGS/VSBYS TO IFR TONIGHT (ALONG WITH
OCNL LIFR CONDITIONS). OVER SBY...AN ONSHORE FLOW AND A MOISTENING
BOUNDARY LAYER WILL RESULT IN DEVELOPING LIFR CONDITIONS AS WELL
TONIGHT...EVEN PRIOR TO THE ARRIVAL OF PCPN.

MVFR/IFR AND PERIODS OF PCPN CONTINUE AT THE TAF SITES FRI AND SAT.
CONDS SHOULD BEGIN TO IMPROVE SAT NIGHT BUT A CHANCE OF SHOWERS WILL
CONTINUE INTO SUN.

&&

.MARINE...
WINDS WILL REMAIN 10 KTS OR LESS TODAY...WHILE GRADUALLY BACKING FROM
S TO E/SE AHEAD AS LOW PRESSURE APPROACHES. THE LOW ORGANIZING 
OVER THE GULF COAST REGION WILL MOVE NORTHEAST AND EVENTUALLY REACH 
A POSITION NEAR THE COASTAL BORDER OF NORTH AND SOUTH CAROLINA BY 
FRIDAY MORNING. AN EASTERLY WIND SHOULD STRENGTHEN DURING THE DAY 
FRIDAY CONTINUING THROUGH FRIDAY NIGHT AND INTO SATURDAY BEFORE 
RELAXING AND BECOMING SOUTHWESTERLY AS THE LOW PRESSURE SYSTEM LIFTS 
TO THE NORTH. WIND SPEEDS APPEAR TO BE SOLIDLY WITHIN SMALL CRAFT 
ADVISORY RANGE...IN FACT...THE LAST 2 NAM RUNS HAVE INDICATED AN 
INCREASED POTENTIAL FOR GALES FRI NIGHT/SAT MORNING. WILL CONTINUE 
TO SIDE CLOSER TO THE GFS/SREF SOLUTIONS...WHICH WOULD FAVOR SCA'S 
OVER GALE WARNINGS...AS FEEL THE NAM MAY BE A BIT OVERDONE WITH THE 
STRENGTHENING ONSHORE FLOW GIVEN THE SYNOPTIC SETUP (I.E. WITH MAIN 
LOW STILL WELL INLAND DURING THIS TIME). THE UPSHOT...HAVE GONE 
AHEAD AND HOISTED SMALL CRAFT ADVISORIES BEGINNING ON FRI...AND WHILE
HEADLINES WILL LIKELY PERSIST INTO THE WEEKEND (AT LEAST FOR
LINGERING HIGH SEAS)...PER LOCAL POLICY HAVE NOT EXTENDED SCA'S 
BEYOND FRIDAY NIGHT OR THE 4TH PERIOD OF THE FCST.

&&

.TIDES/COASTAL FLOODING...
THE LATEST MDL EXTRATROPICAL WATER LEVEL GUIDANCE IS NOW INDICATING 
THE POTENTIAL FOR TIDAL ANOMALIES ON THE ORDER OF 1 TO 1.5 FT ABOVE 
MLLW ON SATURDAY. EXTENDED PERIOD OF ONSHORE FLOW...WITH PERIOD OF 
STRONG ESE WNDS POSSIBLE SATURDAY MORNING...COULD BRING ABOUT SOME 
MINOR TIDAL ISSUES. HOWEVER AT THIS TIME...FORECAST MAXIMUM HIGH 
TIDES REMAIN BELOW MAXIMUM ASTRONOMICAL TIDE OR MAT LEVELS OVER MOST 
SITES. ONE NOTABLE EXCEPTION IS OCEAN CITY...WHERE THE LATEST 
PROJECTED MAX TIDE IS EXPECTED TO PEAK AROUND A HALF FOOT ABOVE THE 
MAT...ALTHOUGH STILL AROUND 0.25 FT BELOW MINOR FLOODING THRESHOLDS. 
WILL CONTINUE TO MONITOR IN THE COMING DAYS.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM FRIDAY TO 6 AM EST SATURDAY FOR 
     ANZ630>633-650-652-654.
     SMALL CRAFT ADVISORY FROM 7 AM FRIDAY TO 6 AM EST SATURDAY FOR 
     ANZ656-658.

&&

$$
SYNOPSIS...MAM
NEAR TERM...ESS
SHORT TERM...ESS/MAM
LONG TERM...AJZ
AVIATION...BKH
MARINE...BKH
TIDES/COASTAL FLOODING...