FXUS61 KLWX 141210
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
810 AM EDT WED MAY 14 2008

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST TODAY. A WEAK COLD FRONT WILL
MOVE INTO THE AREA THURSDAY. LOW PRESSURE WILL APPROACH THE AREA
FRIDAY FROM THE SOUTHWEST. AN UPPER LEVEL TROUGH OF LOW PRESSURE
WILL MOVE OVER THE EASTERN U.S. FOR THE FIRST PART OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRES MOVG OFF THE CST TDA...NEXT CD FNT PRESENTLY MOVG INTO
UPPER MS RVR VALLEY. THIS COMBO WL BRING BACK THE SEASONABLE TEMPS
THAT HV BEEN MISSING FM THE CWA IN RECENT DAYS...AND ALLOW THE RGN
ONE MORE DAY TO ATTEMPT TO DRY OUT B4 THE RAINS RETURN.

AT LEAST FIRST HALF OF DAY WL SEE ABUNDANT SUNSHINE...CLDS START
TO INCRS LATER THIS AFTN. TEMPS REACHING U70S...PSBLY 80 IN SOME
OF THE ERN LOCALES.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
I CAN'T RULE OUT SOME RW ACROSS THE NWRN PART OF THE CWA
OVRNGT...BUT BLV MAJORITY OF THE CWA WL STAY DRY AS CD FNT BEGINS
TO LAY OUT IN A MORE E-W ORIENTATION. LOWS TNGT WL PRBLY AVG 10
DEGS WARMER THAN WED LOWS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS THE COLD FRONT STAGNATES OVER THE MID ATLNC FROM THE EXITING 
UPPER TROF TO THE NE...THE LEFTOVER STNRY BNDRY WILL RESIDE ACROSS 
THE PTMC RIVER VALLEY FOR MUCH OF THE DAY THURS. RESIDUAL PRECIP 
DRNG THE MRNG HRS WILL DISSIPATE ACROSS NERN MD...AND APPROACHING 
LIGHT SHRA ACTIVITY INTO THE SW/RN CWA THRU THE AFTN HRS. WITH WEAK 
ASCENT FROM THE SFC BNDRY...KEPT CHNCE POPS IN FOR THURS THO 
COVERAGE WILL BE FAIRLY ISLTD. THE STNRY BNDRY WILL THEN SLOWLY 
LIFT N/WRD AS A WEAK WARM FRONT AHEAD OF AN APPROACHING SFC LOW. 
BY LATE EVNG THURS MORE STEADY ACTIVITY WILL DEVELOP AND OVERSPREAD 
THE MID ATLNC FROM THE SW...ON THRU THE OVERNIGHT HRS. MUCH OF THIS 
LOOKS TO BE MAINLY STRATIFORM SHRA/S...W/ VERY LITTLE CONVECTIVE 
PTNL /EXCEPT MAINLY LOWER SRN MD/. TRACK OF THE SFC LOW COMING 
BETTER IN LINE BUT THE TIMING STILL AN ISSUE. GFS PUSHING THE 
SYSTEM UP ACROSS LONG ISLAND BY LATE FRI NIGHT...WHILE THE NAM 
BARELY PUSHING THE LOW OUT OF THE CNTRL APLCHNS BY THIS TIME. SR 
MODELS SHOWING A DECENT STRATIFICATION OF QPF VALUES FOR THIS 
SYSTEM ACROSS THE MID ATLNC. WITH THE TYPE OF WEAK LL FORCING AND 
POOR ORGANIZATION OF THE LL ADVECTION PATTERNS UNTIL AFTER THE 
UPPER LEVEL TROF PUSHES OFFSHORE...QPF VALUES NOT LOOKING SO 
ADVANTAGEOUS FOR THE EVENT. RAINFALL DOES LOOK TO BE FAIRLY SCT/D 
AS WELL...MEANING LONG-TERM RAINFALL WILL BE UNLIKELY W/ MAINLY 
MODERATE BANDS OF SHRA ACTIVITY PUSHING ACROSS THE REGION OVERNIGHT. 
FLOODING CONCERNS WOULD REMAIN THO FOR THE TROUBLE AREAS OF THE 
PAST FEW DAYS /ACROSS N CNTRL MD AND EXTREME NRN VA/...NEEDING 
ONLY AROUND HALF AN INCH OF RAIN TO RAISE AREA RIVERS TO ACTION 
STAGES. W/ AREA RIVERS BEGINNING TO DROP OUT OF FLOOD STAGES AND 
ANOTHER DAY TO RECOVER...THE INCOMING RAINFALL MAY NOT BE ENOUGH TO 
RAISE CONCERNS BUT IN A FEW ISLTD AREAS.

AS THE INITIAL UPPER TROF AXIS PUSHES THIS LOW PRES AREA UP THE NE 
COAST...AN UNSEASONABLY STRONG CANADIAN COLD AIR PUSH WILL SLIDE 
INTO THE WRN GREAT LAKES REGION. THIS WILL TIGHTEN THE UPPER PRES 
GRDNT AND WINDS WILL PICK UP DRNG THE MRNG HRS ON SAT. GUSTY WINDS 
EXPTD TO REMAIN ACROSS THE REGION ON SAT AFTN...THO HIGHS STILL 
REACHING INTO THE L70S. 

FROM THERE IT/S BASICALLY A MATTER OF WATCHING WAVE AFTER WAVE OF 
UPPER TROFS SLIDE SE/WRD INTO THE MIDDLE OF NEXT WEEK. THIS MEANS 
PERIODIC CHNCS OF SHRA/S...WINDY AFTNS FROM SAT THRU WED AND 
MODERATED HIGHS REACHING NEAR 70 EACH DAY.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDS XPCTD TDA AND TNGT.

A LOW PRES SYSTEM WILL MOVE INTO THE REGION LATE THURS NIGHT AND 
OFF THE ATLNC COAST INTO EARLY FRI. MAINLY SCT/D AREAS OF LIGHT/MOD 
RAINFALL DRNG THE OVERNIGHT HRS...BUT ONLY A FEW MVFR COND/S W/ THIS 
ACTIVITY. BEHIND THIS SYSTEM...WINDS WILL INCR FOR SAT AFTN AND STAY 
FAIRLY GUSTY ALL THE WAY THRU THE MIDDLE OF NEXT WEEK /ONLY DECR/G 
DRNG THE OVERNIGHT HRS AND PICKING UP EACH AFTN/. AN UNSEASONABLY 
STRONG UPPER LEVEL TROF WILL KEEP THIS ACTIVE PATTERN IN PLACE FOR 
EARLY NEXT WEEK.

&&

.MARINE...
WINDS BLO SCA VALUES TDA AND TNGT.

SCT/D AREAS OF RAINFALL WILL MOVE ACROSS THE WATERS OVERNIGHT THURS 
THRU EARLY AFTN ON FRI. THE SFC LOW WILL MOVE OFF THE MID ATLNC 
COAST EARLY FRI W/ GUSTY WINDS OVERSPREADING THE BAY REGION BY SAT 
AFTN. SCA COND/S WILL BE PSBLE AND ARE EXPTD EACH DAY FROM SAT THRU 
MID NEXT WEEK.

&&

.HYDROLOGY...
WATERS HAVE DROPPED BELOW FLOOD STAGE AT BOTH POINT OF ROCKS AND
LITTLE FALLS...SO FLD WRNGS HV BEEN TAKEN DOWN.

&&

.TIDES/COASTAL FLOODING...
HAVE BEEN IN CONTACT WITH WASHINGTON HARBOR...ALEXANDRIA AND DC
POLICE...AND MINOR FLOODING CONTINUES. WITH TIDEAL ANOMALIES COMING
DOWN...WARNING CRITERIA IS NOT BEING MET SO WARNING WILL BE
ALLOWED TO EXPIRE. HOWEVER...MINOR WATER ISSUES WILL CONTINUE AT
LEAST FOR THE NEXT COUPLE HOURS AND HAVE THERFORE ISSUED COASTAL
FLOOD ADVISORY. WATER PROBLEMS ARE A RESULT OF THE COMBINATION OF
FRESHWATER FLOWING DOWN THE POTOMAC AND ABOVE NORMAL TIDES.

WILL REEVLATE AT NOON...BUT INITIAL DATA SUGGESTS WATER PROBLEMS
MAY CONTINUE BEYOND NOON ACROSS DC...AND MAY AFFECT OTHER COASTAL
AREAS. THIS WILL BE MORE LINKED TO THE NEXT HIGH TIDE CYCLE THIS
AFTERNOON WHICH WILL BE UP TO 2 FEET ABOVE NORMAL.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL NOON EDT TODAY FOR DCZ001.
MD...NONE.
VA...COASTAL FLOOD ADVISORY UNTIL NOON EDT TODAY FOR VAZ054.
WV...NONE.
MARINE...NONE.

&&

$$
TIDES/COASTAL FLOODING...PELOQUIN 
OTHER...WOODY!/GMS