346 FXUS61 KLWX 120919 CCA AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 420 AM EST WED MAR 12 2003 ...SHORT TERM...TODAY AND TONIGHT... AT 08Z...SKIES CLR CWA WIDE WITH THE EXCEPTION OF RIGHT ALONG CHES BAY WHERE SHALLOW MARINE LAYER HAS CREATED STRATUS AT 1KFT. SHALLOW INVERSION OVER REST OF CWA RESULTING IN LIGHT WINDS. EXPECTING SOME PATCHY LIGHT FOG TO DEVELOP DUE TO THIS INVERSION TOWARD DAWN. BECAUSE WINDS ARE RELATIVELY LIGHT...DONT EXPECT LOW CLDS ALONG BAY TO MOVE VERY FAR INLAND. REGARDLESS...ANY LOW CLDS OR FOG THAT FORM WILL QUICKLY MIX OUT BY 9 AM AS INVERSION BREAKS. WEAKENING SHORT WAVE NOW OVER S INDIANA IS FCST TO PUSH E ACROSS CWA THIS AFT. MODELS ONLY FCST PRECIP IN MTNS WITH THIS SYSTEM...BUT AM CONCERNED THAT SOME LIGHT PRECIP COULD MAKE IT OVER THE RIDGES AS SIG MID LVL MOISTURE ARRIVES DURING THE MID AFT HRS. AT THE SFC...WINDS WILL BE TURNING WSW WHICH WILL GIVE CWA DOWNSLOPE COMPONENT. MODELS FCST DOWNSLOPE WILL KEEP ATMOS DRY ENOUGH TO PREVENT RA FROM REACHING GROUND...EVEN THOUGH SYSTEM STILL HAS SIG VVEL WITH IT /AT BOTH 500 AND 700MB/. BECAUSE ATMOS WILL BECOME SATURATED AT 5KFT BY LATE THIS AFT AND LIFT IS MOVING THRU...AM NOT COMFORTABLE WITH COMPLETELY DRY FCST E OF MTNS...ESPECIALLY SINCE DEW PTS ARE RUNNING 5 DEG HIGHER THAN GUIDANCE ATTM. AFTER COORD WITH AKQ HAVE DECIDED TO MENTION AFT SPRINKLES E OF MTNS. WILL HAVE CHANCE -RA FAR W ZONES LATE MORNING ON. WEAK COLD FRONT PASSES THRU CWA FROM NW TO SE AROUND 00Z TONIGHT. BEHIND FRONT...LITTLE IF ANY LIFT WILL BE PRESENT UNTIL APPROACH OF LOW THU 12Z. NOT EXPECTING MUCH IN THE WAY OF PRECIP IN THE PREDAWN HOURS. FRONT STALLS OVER S VA LATE TONIGHT AND LOW PRES DEVELOPS ALONG FRONT OVER TN. SIG LIFT ASSOC WITH LOW APPROACHES WSW ZONES TOWARD DAWN. THAT AREA OF LIFT WILL BE THE START OF THE SIG PRECIP WHICH WILL CONTINUE INTO THU. MMARGRAF LONG TERM (THU-TUE) THU...WARM FRONT TO THE SOUTH WILL ONLY MAKE INTO A FEW COUNTIES OF OUR CWA. SOME SPREAD IN TEMPS BETWEEN MAV/MET GUIDANCE. WENT WITH COOLER MET NUMBERS DUE TO EXPECTED CLOUDS AND PRECIP. ALSO MET NUMBERS LOOK CLOSER TO NORMAL HIGHS FOR THIS DATE WHICH ARE ABT 53-54. WENT MID TO UPPER 40S COUNTIES ADJACENT TO PA BORDER. OVR CHO/NHK/AUGUSTA COUNTIES WHERE WARM FRONT WILL SNEAK IN WENT WITH HIGHS IN THE LOW 60S AND WHERE WILL BE A DOWNSLOPE COMPONENT TO THE WIND FOR A FEW HRS. RAIN WILL OVERSPREAD THE AREA FROM WEST TO EAST AS THE DAY PROGRESSES. STILL SOME MINOR TIMING DIFFERENCES WHEN EXACTLY PRECIP WILL GET HERE BUT NO DOUBT PRECIP CHANCES ARE GOING TO BE HIGH AS THERE IS STG FRONTAL CONVERGENCE...PLENTY OF MOISTURE AND LIFT AND MID-LVL TROF TRACKS ACROSS THE AREA. BOTH GFS/ETA AND LATEST HPC QPF GRAPHIC INDICATE PRECIP IS OUT OF HERE BY 00Z FRI. FRI...SUNNY SKIES WITH HIGHS AROUND NORMAL. SAT-SUN...VERY NICE WITH LOTS OF SUN AND HIGHS IN THE 60S. SUNDAY LOOKS THE WARMEST DAY WITH A FEW LUCKY SPOTS REACHING THE 70 DEG MARK. MON-TUE...LEFT GRIDS UNTOUCHED AS THERE IS STILL CONSIDERABLE UNCERTAINTY BETWEEN MODELS. STILL LOOKS LIKE A BACK DOOR COLD FRONT WILL MAKE IT THRU THE AREA MON NITE COOLING THINGS OFF FOR THE MIDDLE OF NEXT WEEK. ROSA .LWX... DC...NONE. MD...NONE. VA...NONE. WV...NONE.