092 
FXUS61 KLWX 222000
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
300 PM EST SUN NOV 22 2009

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RETREAT TO THE NORTH TONIGHT WHILE AN 
AREA OF LOW PRESSURE DEVELOPS OFF THE SOUTHEAST COAST. THIS LOW WILL 
TRACK UP THE MID-ATLANTIC COAST MONDAY AND TOWARDS NEW ENGLAND 
MONDAY NIGHT INTO TUESDAY. HIGH PRESSURE WILL BUILD IN BEHIND THIS 
SYSTEM LATER TUESDAY AND WEDNESDAY. A COLD FRONT WILL PASS THROUGH 
THURSDAY BRINGING UNSETTLED CONDITIONS. AN UPPER-LEVEL LOW WILL 
CONTINUE TO IMPACT THE REGION LATE IN THE WEEK. 
&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CURRENT ANALYSIS SHOWS HIGH PRESSURE CENTERED OVER NEW ENGLAND THIS 
AFTERNOON. A SURFACE LOW CONTINUES TO TRACK ALONG THE GULF COAST 
STATES. THE UPPER-LEVEL LOW ASSOCIATED WITH THE SURFACE LOW IS 
TRACKING TOWARD THE TENNESSEE VALLEY.  

SURFACE HIGH WILL CONTINUE TO RETREAT TO THE NORTHEAST TONIGHT WHILE 
THE SURFACE LOW REDEVELOPS ALONG THE SOUTHEAST COAST. THE 
UPPER-LEVEL LOW ASSOCIATED WITH THIS SYSTEM WILL TRACK THROUGH THE 
TENNESSEE VALLEY TONIGHT AND TOWARD SOUTHWESTERN VIRGINIA BY MONDAY 
MORNING. 

A LOW-LEVEL EAST-SOUTHEAST FLOW AROUND THE DEPARTING HIGH AND THE 
LOW PRESSURE SYSTEM WILL BRING INCREASING AMOUNTS OF MOISTURE OFF 
THE ATLANTIC OCEAN. THE MOISTURE INCREASE COMBINED WITH ISENTROPIC 
LIFT WILL RESULT IN INCREASING LOW CLOUDS LATER THIS EVENING INTO 
THE OVERNIGHT HOURS. WITH THE ACTUAL STORM SYSTEM REMAINING WELL TO 
THE SOUTH...DRY CONDITIONS ARE EXPECTED THROUGH THIS EVENING. 
HOWEVER...RAIN AHEAD OF THE STORM SYSTEM WILL BEGIN TO OVERSPREAD 
THE REGION FROM SOUTH TO NORTH LATE.  
&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THE SURFACE LOW WILL CONTINUE TO TRACK UP THE MID-ATLANTIC COAST 
WHILE THE UPPER-LEVEL LOW SHEARS APART AS IT TRACKS ACROSS OUR 
REGION. A LOW-LEVEL EASTERLY FLOW COMBINED WITH ISENTROPIC LIFT WILL 
RESULT IN LOW CLOUDS ALONG WITH OCCASIONAL RAIN. RAINFALL AMOUNTS 
SHOULD BE ON THE LIGHT SIDE DUE TO THE LACK OF STRONG DYNAMICS WITH 
THIS SYSTEM. MAX TEMPS WILL BE SEVERAL DEGREES COOLER THAN RECENT 
DAYS DUE TO THE RAINFALL...RANGING FROM THE MID AND UPPER 40S ACROSS 
THE POTOMAC HIGHLANDS INTO THE SHENANDOAH VALLEY...TO NEAR 50 IN 
WASHINGTON AND BALTIMORE...TO THE LOWER AND MIDDLE 50S ACROSS LOWER 
SOUTHERN MARYLAND. 
&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
ANY PCPN LINGERING MON NGT WUD BE AS A RSLT OF THE DEF AXIS ACRS 
CWFA. HWVR...LOPRES RATHER WEAK...AND FAR OFFSHORE...SO DONT THINK 
THAT PCPN WUD BE PLENTIFUL. WUD BE MORE CONCERNED ABT DZ...BUT SFC 
WNDS NLY NOT NE/ELY.

HIPRES BRIEFLY BLDS TUE-TUE NGT. BUT IT SHUD BE A DIRTY RDG AS AMPLE 
LLVL MSTR STILL LINGERS. SUNSHN SHUD BE LMTD...ASSUMING IT CAN BRK 
THRU MARINE STRATUS. BASED ON TKNS OF MARINE DECK ON MDL 
TIME-HGTS...THAT/LL BE A BIG ASSUMPTION. SUSPECT LLVL CLDS WL BE 
SUFFICIENT FOR DZ TO DVLP TUE NGT...SPCLY SINCE SFC HIGH WEDGED A LA 
CAD AND H9-8 FLOW BCMG SLY.

CMPLX SCENARIO SETTING UP FOR MID WK...AS S/WV ENERGY DROPS INTO 
CNTRL PLAINS...CUTTING OFF H5 LOW BY TUE. ADDTL VORTS CARVE OUT A 
2ND LOW...WHICH WL DEEPEN LOW OVR GRTLKS BY THU. LCLLY...CWFA WL 
RECEIVE ISENT LIFT...THEN GLANCING BLOW OF PVA WED. THUS...CLDS 
GOING NOWHERE...AND CHC SHRA RETURNS. SOME MIXING CUD PUNCH HOLES IN 
THE CLD DECK BHD VORT LT WED-WED NGT. 

TEMPS FAIRLY TEMPERATE THRU THE PD. NOT MUCH SPREAD IN MOS TEMPS 
TMRW NGT-TUE...AND A SLGTLY LRGR SPREAD TUE NGT. CONSIDERING 
CLDS...STAYED AWAY FM BIG DIURNAL SWINGS-- WARM SIDE OF MEAN FOR 
MIN-T BUT COOLER SIDE FOR MAXT.

XTNDD...DP H5 TROF AXIS/CUTOFF LOW TO PIVOT ACRS CWFA THU-FRI. THIS 
CYCLE...GDNC - SPCLY GFS - NOW TRANSFERRING ENERGY TO DVLPG CSTL 
SYSTM LT THU NGT-ELY FRI MRNG. BUT EVEN THE MORE STBL ECMWF TRENDING 
TWD GFS. EITHER WAY THE END RSLT WL BE SIMLR...FVRBL SUPPORT FOR 
PCPN...AND SIGNALS THAT HIER ELEVS CUD RECEIVE SNW. WL INCR POPS 
THU-THU NGT...AND STICK W/ MTN SNW/MIX ONCE CAA UPON US THU PM. NW 
FLOW PTTN THRU SAT. WL ENHANCE UPSPL PCPN THRU THAT TIME. 
&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH EARLY THIS EVENING WITH 
INCREASING HIGH CLOUDS. AS LOW PRESSURE DEVELOPS OFF THE SOUTHEAST 
COAST...AN ONSHORE FLOW WILL RESULT IN LOW CLOUDS LATE THIS EVENING 
AND OVERNIGHT. RAIN AND DRIZZLE WILL OVERSPREAD THE TERMINALS MONDAY 
MORNING WHILE A NORTHEAST FLOW CONTINUES TO USHER IN PLENTY OF 
LOW-LEVEL MOISTURE FROM THE ATLANTIC. CIGS WILL LIKELY DROP TO IFR 
LEVELS LATE TONIGHT AND LAST THROUGH MONDAY. VSBYS WILL DROP 
MAINLY TO MVFR LEVELS LATE TONIGHT...BUT IFR VSBYS ARE POSSIBLE ONCE 
THE RAIN BEGINS.
 
FLGT RESTRICTIONS PSBL THRU MUCH OF WK AS UNSTTLD CONDS ABOUND. IF 
THERE WERE A BRK IT WUD COME TUE AFTN/EVE...BUT LOW CLDS/DZ LKLY TO 
RTN TUE NGT.
&&

.MARINE...
LOW PRESSURE WILL DEVELOP OFF THE SOUTHEAST COAST TONIGHT. A 
STRENGTHENING PRESSURE GRADIENT DUE TO THE LOW WILL BRING SCA WIND 
GUSTS ACROSS THE CHESAPEAKE BAY AND LOWER TIDAL POTOMAC OVERNIGHT. 
AS LOW PRESSURE TRACKS UP THE MID-ATLANTIC COAST MONDAY...MORE SCA 
CONDITIONS ARE EXPECTED ACROSS THE LOWER TIDAL POTOMAC AND 
CHESAPEAKE BAY. HAVE CAPPED WIND GUSTS MONDAY AROUND 15 KNOTS ACROSS 
THE UPPER TIDAL POTOMAC...BUT WITH FASTER WINDS LESS THAN A THOUSAND 
FEET FROM THE SURFACE...ANY MIXING WOULD BRING STRONGER WIND GUSTS 
LATER MONDAY MORNING/AFTERNOON. THIS WILL HAVE TO BE MONITORED BY 
LATER SHIFTS. 

G20KT LKLY TO CONT INTO TMRW NGT DUE TO NLY FLOW...SPCLY FOR MAIN 
CHANNEL BAY BLO POOLES ISL AND FOR LWR PTMC. WL INCL BIG INLETS BUT 
NOT BALT HARBOR/PAX RIVER. HIPRES RDG SHUD DECR WNDS TUE-WED...ALTHO 
LOW CLDS SHUD BE PLENTIFUL AND RA A PSBLTY BY WED.
&&

.TIDES/COASTAL FLOODING...
WITH HIGH PRESSURE WELL TO OUR NORTH...AN ONSHORE FLOW HAS DEVELOPED 
THIS AFTERNOON. THE FLOW IS WEAK AND TIDAL ANOMALIES RANGE FROM NEAR 
NORMAL TO ABOUT ONE HALF FOOT ABOVE NORMAL. LOW PRESSURE IS EXPECTED 
TO DEVELOP OFF THE SOUTHEAST COAST TONIGHT AND THE GRADIENT IS 
EXPECTED TO TIGHTEN BETWEEN THESE TWO SYSTEMS OVERNIGHT AND MONDAY. 

AS THE LOW TRACKS UP THE MID-ATLANTIC COAST MONDAY INTO MONDAY 
NIGHT...THIS WILL CAUSE TIDAL ANOMALIES TO INCREASE DURING THIS 
TIME. LATEST CBOFS AND EXTRATROPICAL MODELS CONTINUE TO INDICATE 
THAT WATER LEVELS WILL REMAIN BELOW THRESHOLDS FOR MINOR COASTAL 
FLOODING. THE ASTRONOMICAL NORMS FOR WATER LEVELS ARE ALSO ON THE 
LOWER SIDE DUE TO THE LUNAR CYCLE APPROACHING THE FIRST QUARTER 
PHASE. HAVE NOT ISSUED AN ADVISORY FOR THESE TWO REASONS...BUT THIS  
WILL HAVE TO BE MONITORED BY LATER SHIFTS. 
&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EST TUESDAY 
     FOR ANZ531>534-537-539>541-543.
     SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 8 PM EST MONDAY 
     FOR ANZ530-538-542.

&&

$$
SYNOPSIS...LASORSA
NEAR TERM...LASORSA
SHORT TERM...LASORSA
LONG TERM...HTS
AVIATION...LASORSA/HTS
MARINE...LASORSA/HTS
TIDES/COASTAL FLOODING...LASORSA

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