000 FXUS61 KLWX 170814 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 315 AM EST FRI MAR 17 2000 07Z SURFACE ANALYSIS SHOWING COLD FRONT EXTENDING FROM CENTRAL PA THROUGH EASTERN WV... JUST TO THE WEST OF OUR CWA. KLWX INDICATING A PERSISTENT AREA OF SHOWERS OVER LOWER SOUTHERN MD.. WITH MORE SHOWERS ORGANIZING ALONG AND WEST OF THE BLUE RIDGE. BACK EDGE OF SHOWERS APPEARS TO BE RIGHT ALONG THE FRONT AT TIME.. PER KFCX AND KRLX RADARS. 00Z ETA AND NGM HAD FRONT TIMED WELL AT 06Z... AND 06Z RUC ALSO APPEARS TO HAVE A GOOD HANDLE ON THE SYSTEM. ALL OF THE MODELS BRING THE FRONT THROUGH BETWEEN 09Z AND 12Z AND INDICATE AN ABRUPT END TO THE PRECIP SHORTLY AFTER. VERY STRONG DOWNSLOPE FLOW DEVELOPING AFTER FRONTAL PASSAGE.. AND ETA/NGM BOTH INDICATE STRONG DRYING AT ALL LEVELS BETWEEN 12Z AND 15Z. UPPER LEVEL SYSTEM TO PASS OVERHEAD AROUND MID DAY... BUT EXPECT THAT TO BE DRY. CLEARING LINE ON IR/FOG LOOPS RUNS FROM SW ONTARIO THROUGH NW OHIO AND CENTRAL INDIANA.... MOVING QUICKLY EASTWARD. APPROACH OF DRIER AIR AND STRENGTHENING OF DOWNSLOPE WINDS SHOULD RESULT IN SOME SUNSHINE OVER THE AREA BY MID MORNING. CLEAR SKIES EXPECTED OVERNIGHT AND THROUGH MOST OF THE DAY TOMORROW AS HIGH MOVES JUST TO THE NORTH. WINDS WILL BE A CONCERN TODAY.. AS MODEL SOUNDINGS SHOWING 25-30 KT WINDS THROUGH THE MIXING LAYER. WINDS SHOULD GRADUALLY WEAKEN LATE TONIGHT AND TOMORROW WITH HIGH WORKING INTO AREA. TEMPS BEHIND THE FRONT ARE MAINLY IN THE 30S... WHILE CURRENT READINGS OVER OUR CWA ARE STILL IN THE 50S. WILL MENTION AN EARLY AM HIGH NEAR OR SLIGHTLY BELOW 08Z READINGS.. BUT EXPECT A HEALTHY DROP IN TEMPS DURING THE MORNING HOURS. WITH DOWNSLOPE WINDS AND WITH SOME SUN... TEMPS SHOULD LEVEL OUT THIS AFTERNOON. VERY COLD AND DRY AIR MASS IN PLACE TONIGHT... WITH DEW POINTS EXPECTED TO DROP TO NEAR 10 DEGREES OVER MOST OF THE AREA. WINDS MAY KEEP TEMPS UP A BIT... BUT STILL PLAN TO UNDERCUT FWC TEMPS BY A COUPLE OF DEGREES. WILL BE MAKING SOME CHANGES TO BOTH TEMPS AND PRECIP IN THE EXTENDED. AVN AND YESTERDAY'S MRF BOTH INDICATE A MOIST SE FLOW AND GOOD WARM ADVECTION DEVELOPING SATURDAY NIGHT AND SUNDAY. WILL MENTION INCREASING CLOUDS SAT NIGHT... AND INTRODUCE A CHANCE OF RAIN SUN. WILL ALSO ADD MORE CLOUDS AND A CHANCE OF RAIN MONDAY AS SYSTEM OVER SE US MOVES CLOSER AND WE REMAIN IN A WARM ADVECTION/UPSLOPE PATTERN. HAVE RAISED TEMPS IN LATER PERIODS.. IN BETTER AGREEMENT WITH MRF AND NCEP GUIDANCE. .LWX...SCA FOR TIDAL POTOMAC AND MD PORTION OF CHESAPEAKE BAY. MARGRAF!