Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 291403 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1003 AM EDT FRI APR 29 2016 .SYNOPSIS... A COLD FRONT WILL REMAIN STALLED TO THE SOUTH TODAY. ANOTHER WEAK WAVE OF LOW PRESSURE WILL RIDE ALONG THE BOUNDARY. THE BOUNDARY WILL DROP SOUTH SATURDAY...THEN LOW PRESSURE MOVES THROUGH THE MID-ATLANTIC SUNDAY AND MONDAY. ANOTHER FRONT WILL MOVE THROUGH LATER NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
A RELATIVE LULL IN ACTIVITY ACROSS THE AREA THIS MORNING...WITH ONLY A FEW SHOWERS EMBEDDED WITHIN THE DZ AND LIGHT FOG...MAINLY ACRS NE MD. WEDGE OF HIGH PRESSURE EVIDENT EAST OF THE MTNS IN VA...WITH MAIN FRONT STILL DRAPED ACROSS NC. ON THE WHOLE...FCST IN GOOD SHAPE. GUIDANCE HINTING THAT CLOUDS MAY ERODE SOME BY THIS AFTERNOON ACROSS SOUTHWESTERN PORTIONS OF THE AREA. PERHAPS NOT CLEARING...BUT AT LEAST LIFTING. ELSEWHERE EXPECT LOW CLOUDS TO HOLD FIRM. THIS COULD LEAD TO A GRADIENT IN TEMPERATURES...WITH COOLEST TO THE NE. HAVE SHADED A LITTLE BELOW MODEL BLEND. BASED ON LTST LAMP...MAXT FCST SEEMS ON TRACK. W/ A LACK OF ORGANIZED FORCING...IT SHOULD BE ONE OF THE DRIER PDS IN THE NEXT CPL OF DAYS. VORT MAX CURRENTLY OVER LAKE MICHIGAN WILL PASS TO THE NORTH LATE THIS AFTERNOON. THIS WILL BRING A RENEWED CHANCE OF LIGHT SHOWERS MOVING FROM NW TO SE ACROSS THE REGION. HAVE KEPT POPS AT CHANCE GIVEN EXPECTED SCATTERED/LIGHT NATURE. THIS WILL ALSO SERVE TO GIVE THE FRONTAL ZONE A NUDGE TO THE SOUTH AND DRY OUT THE ATMOSPHERE... EXCEPT AT THE LOW LEVELS. WITH A CONTINUED OVERRUNNING FLOW...HAVE KEPT PATCHY DZ WORDING IN THE FORECAST LATE TONIGHT. LIGHT FOG POSSIBLE ONCE AGAIN TOO. SAME TREND...ONLY SMALL DROP IN TEMPS OVERNIGHT.
-- End Changed Discussion --
&& .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... THE TREND FOR THE WEEKEND CONTINUES TO BE LESS DRY. NOT A TOTAL WASHOUT...BUT PROLONGED BREAKS WILL BE SPARSE ONCE ISENTROPIC LIFT BEGINS AHEAD OF LOW PRESSURE OVER THE PLAINS. RAIN COULD ARRIVE IN THE MOUNTAINS SATURDAY MORNING...AND AT LEAST A CHANCE OF IT SPREADING EAST DURING THE AFTERNOON. STILL SOME TIMING DIFFERENCES. BUT BROUGHT POPS TO CATEGORICAL SATURDAY NIGHT AND WORDED AS RAIN...LOOKS LIKE A GOOD SLUG OF MOISTURE...AND PERHAPS BE MODERATE AT TIMES. TRENDED MAX T ON SATURDAY DOWN A LITTLE. SFC LOW AND OPENING UPPER WAVE WILL BE APPROACHING THE OHIO VALLEY SUNDAY INTO SUNDAY NIGHT. CONTINUED LIFT AND MOISTURE ADVECTION WILL MEAN HIGH CHANCES OF SHOWERS CONTINUING. BIGGEST UNCERTAINTY IS WHAT HAPPENS TO WEDGE FRONT ON SUNDAY. PLAYING TOWARD MODEL BIASES...ONCE AGAIN WENT BELOW THE MODEL BLEND. HOWEVER...CENTRAL VA MAY BE ABLE TO BREAK INTO THE WARM SECTOR. AND LAPSE RATES ALOFT WILL BE FAIRLY STEEP ACROSS THE ENTIRE AREA. HAVE SLIGHT CHANCE OF THUNDER NORTH AND CHANCE SOUTH. WITH MODERATE DEEP LAYER SHEAR...THERE COULD BE SOME STRONGER STORMS TOWARD CENTRAL VA...AND THIS AREA IS INCLUDED IN SPC DAY 3 MARGINAL RISK. MODEL CONSENSUS ATTM IS FOR LOW TO BE PULLING AWAY LATE SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH THURSDAY/... LATEST GUIDANCE SUPPORTS THE IDEA OF THE LOW PRESSURE DEPARTING THE AREA FASTER ON MONDAY...THOUGH PASSING TROUGH AND NORTHEAST FLOW MAY KEEP A FEW SHOWERS GOING ACROSS THE REGION. THE FLOW MAY TURN NORTHWEST IN THE AFTERNOON WHICH COULD ALLOW CLOUDS TO BREAK AND SOME SUN TO REACH THE GROUND...AND ALLOW TEMPS TO NEAR 70. GUIDANCE MOSTLY AGREES ON A DRIER TREND MONDAY NIGHT BUT TUESDAY ONWARD IS STILL QUESTIONABLE WITH THE EC STILL SHOWING A WAVE MOVING NORTHEAST FROM THE GULF...WHILE THE GFS IS MUCH SLOWER BRINGING A WAVE UP. BOTH MODELS DO SHOW THE WAVE OFF THE SOUTHEAST COAST WEDNESDAY BUT ARE SHUNTED EAST OF THE PREVIOUS EC RUNS...KEEPING US MOSTLY DRY. GFS AND EC BOTH HAVE ANOTHER FRONT SLIDE IN FROM THE NORTHWEST ON THURSDAY WITH MUCH COOLER AIR BEHIND IT. GFS IS FAIRLY DRY WHILE EC GENERATES A FAIR AMOUNT OF SHOWERS. OVERALL IT WILL BE A COOLER THAN NORMAL WEEK WITH HIGHS MOSTLY NEAR OR BELOW 70. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
WIDESPREAD IFR/LIFR CONDITIONS THIS MORNING. MOST GUIDANCE HAS CIGS LIFTING TO MVFR BY THIS AFTERNOON...BUT LOW CONFIDENCE ON HOW HIGH. WL STICK WITH PERSISTENCE FOR NOW. COULD BE A FEW SHOWERS LATE THIS AFTERNOON...BUT COVERAGE WILL PRECLUDE TAF MENTION FOR NOW. OTHERWISE EXPECT PREDOMINANTLY DZ. CONDITIONS WILL DETERIORATE AGAIN TONIGHT WITH WIDESPREAD IFR EXPECTED WITH LOW CIGS...DZ...AND FOG. SHOULD BE SOME IMPROVEMENT ON SATURDAY WITH PERHAPS VFR DURING THE MIDDAY. BROAD AREA OF RAIN...PERHAPS MODERATE...WILL MOVE ACROSS THE AREA SATURDAY NIGHT WITH SUB-VFR CONDITIONS LIKELY. SHOWERS CONTINUE SUNDAY INTO SUNDAY NIGHT WITH THUNDER POSSIBLE...ESPECIALLY CHO. TEMPORAL RESOLUTION OF CIGS/VSBYS BECOMES LESS CERTAIN DURING THIS TIME. CIGS AND VIS LIKELY TO IMPROVE GRADUALLY MONDAY WITH VFR PROBABLE BY TUESDAY.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
ONSHORE FLOW WILL CONTINUE THROUGH SATURDAY. GENERALLY EXPECTING 5- 10 KT WITH OCCASIONAL INCREASES TO 15 KT. LIGHT FOG AND DZ WILL CONTINUE AT TIMES. NEXT ROUND OF RAIN AND ASSOCIATED LLJ IS A LITTLE QUICKER NOW AND SCA CONDITIONS MAY BE REACHED AS EARLY AS SATURDAY NIGHT. THIS POSSIBILITY WILL REMAIN SUNDAY INTO SUNDAY NIGHT... ALTHOUGH PERHAPS NOT CONTINUOUSLY. THUNDERSTORMS WILL ALSO BE POSSIBLE SUNDAY AFTERNOON AND EVENING. SCA CONDITIONS REMAIN POSSIBLE WITH LOW PRESSURE PASSING ON MONDAY.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING...
-- Changed Discussion --
TIDAL ANOMALIES AT OR BELOW A HALF-FOOT ABV ASTRO NORMS ATTM. AT THAT DEPARTURE...NO ISSUES ARE ANTICIPATED WITH THE UPCOMING TIDE CYCLE. WILL NEED TO CONTINUE WATCHING ANOMALIES AS WITH THE CONTINUED NORTHEAST FLOW...WATER LEVELS MAY RE-BUILD IN THE BAY AND POTOMAC.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...RCM NEAR TERM...HTS/ADS SHORT TERM...ADS LONG TERM...RCM AVIATION...HTS/ADS/RCM MARINE...ADS/RCM TIDES/COASTAL FLOODING...HTS/RCM

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.