Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 261845 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 245 PM EDT SUN JUL 26 2015 .SYNOPSIS...
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A COLD FRONT WILL APPROACH THE WATERS FROM THE NORTHWEST TONIGHT. THE FRONT WILL STALL NEAR THE WATERS MONDAY THEN DISSIPATE BY MONDAY NIGHT AS HIGH PRESSURE REGAINS CONTROL. THE HIGH WILL MOVE OFFSHORE WEDNESDAY.
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&& .NEAR TERM /THROUGH MONDAY NIGHT/...
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SCT T-STORMS EXPECTED TO DEVELOP THIS AFTERNOON AND LINGER THROUGH THE EVENING IN WARM HUMID AIR MASS. THESE EXPECTED TO MOVE TO THE ESE AT 10-15KT AND REACH THE BAY LATER THIS EVENING. STORY REPEATS ITSELF TOMORROW SINCE THERE IS NO CHANGE IN AIR MASS. WEAK SHEAR SHOULD PRECLUDE ANY SEVERE WX. DRIER AIR WORKS INTO THE AREA LATE MON NIGHT.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
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A WEAK PRESSURE TROUGH WILL PERSIST OVER SOUTHWESTERN PARTS OF THE CWA TUESDAY AS HIGH PRESSURE BUILDS OVER NORTHERN PARTS OF THE AREA. COULD SEE SCATTERED LOW CLOUDS FIRST THING TUESDAY MORNING AS A LIGHT ONSHORE FLOW TAKES HOLD IN THE WAKE OF THE DISSIPATING FRONTAL BOUNDARY. WITH THE PRESSURE TROUGH IN PLACE AND A LIGHT/MOIST EASTERLY UPSLOPE FLOW...A FEW WIDELY SCATTERED SHOWERS OR A THUNDERSTORM COULD POP UP DURING PEAK HEATING OVER THE SOUTHWESTERN CORNER OF THE AREA. OTHERWISE...JUST SCATTERED- BROKEN DIURNAL CUMULUS EXPECTED WITH TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL. HIGH PRESSURE MOVES OVERHEAD TUESDAY NIGHT. LOWS NEAR NORMAL ARE EXPECTED UNDER A PARTLY TO MOSTLY CLEAR SKY. AS THE HIGH MOVES OFFSHORE WEDNESDAY...HOT AND HUMID SOUTHERLY FLOW WILL RETURN...BOOSTING HIGH TEMPERATURES INTO THE UPPER 80S AND LOWER 90S. HEAT INDEX VALUES MAY APPROACH 100F DURING THE AFTERNOON IN THE METRO AREAS.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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HIGH PRES DOMINATES CONDITIONS WED NIGHT INTO FIRST HALF OF THU BEFORE A COLD FRONT APPROACHES FROM THE NW LATER THAT DAY. SHOWERS AND TSTMS PSBL... WITH UNCERTAINTY IN TIMING AND COVERAGE OF THESE ATTM. FRONT MOVES ACROSS THU NIGHT AND STALLS OVER/OFF THE SE OF OUR CWA THROUGH SUNDAY AS IT WEAKENS. DEPENDING ON HOW CLOSE THIS BOUNDARY STALLS TO OUR AREA... SOME SHOWERS AND TSTMS ARE PSBL IN THE SOUTHERN PART OF OUR CWA... SO KEPT A CHANCE OF POPS DURING THIS PERIOD FOR THAT REGION. HIGH TEMPS WILL BE IN THE MID 90S THU... WITH HEAT INDEXES PSBLY REACHING THE LOW 100S IN SOME AREAS. SAT THROUGH SUN HI TEMPS WILL BE IN THE UPR 80S TO LOW 90S.
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&& .AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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SCT T-STORMS EXPECTED THIS AFTERNOON AND TRACK GENERALLY ESE 10-15 KT. ACTIVITY IS EXPECTED TO BE DISORGANIZED. THUS...TIMING AND EXACT LOCATION UNCERTAIN SO WILL COVER WITH VCTS FOR NOW. SAME STORY AGAIN TOMORROW. MORE CLOUD COVER TONIGHT SHOULD INHIBIT PATCHY FOG FORMATION AS OPPOSED TO PREVIOUS NIGHTS. IF ANY FOG DEVELOPS SHOULD BE BRIEF. MAINLY VFR EXPECTED TUE-WED. OUTSIDE CHANCE SUB-VFR MAINLY AT BWI/MTN TUE AM W/ POTL STRATUS DUE TO MOIST ELY FLOW. WINDS GENERALLY AOB 10 KT...ELY TUE BCMNG SLY TUE NIGHT-WED AROUND 10 KT. VFR CONDITIONS EXPECTED WED NIGHT INTO EARLY THU. SUB-VFR CONDITIONS PSBL THU AFTN DUE TO SHOWERS AND TSTMS.
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&& .MARINE...
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HAVE RAISED SCA FOR THE MIDDLE AND UPPER POTOMAC UNTIL 00Z TONIGHT. SEA BREEZE EFFECTS ENHANCING WIND SPEEDS AND DIE DOWN AFTER SUNSET. WINDS SHOULD WEAKEN OVER THE BAY TOMORROW. SCA REMAINS VALID THERE UNTIL 08Z MON. SUB-SCA CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY NIGHT AS HIGH PRESSURE MOVES OVER THE WATERS. THE HIGH MOVES OFFSHORE WEDNESDAY RESULTING IN SOUTHERLY CHANNELING AND POTENTIAL SMALL CRAFT GUSTS. SCA CONDITIONS PSBL FOR WED NIGHT INTO THU.
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&& .TIDES/COASTAL FLOODING...
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SOUTHERLY FLOW HAS INCREASED AND CONTINUES TO NUDGE TIDAL ANAMOLIES UPWARDS THIS AFTERNOON. THE HIGHER OF THE TWO HIGH TIDE CYCLES OVERNIGHT WILL LIKELY RESULT IN MINOR INUNDATION AT VULNERABLE SITES /PARTICULARLY ANNAPOLIS...BUT POSSIBLY UP INTO BALTIMORE HARBOR AS WELL/. ESTOFS IS STILL RUNNING A LITTLE HIGH BUT NOT QUITE AS MUCH HIGHER COMPARED TO OTHER GUIDANCE AS IN PREVIOUS DAYS...SO HAVE CONSIDERED ITS OUTPUT WITH THIS ASSESSMENT. COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR TONIGHT`S HIGH TIDE CYCLE.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT MONDAY FOR MDZ011-014. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR ANZ530>534- 537>543. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ535-536.
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&& $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...DFH LONG TERM...IMR AVIATION...IMR/LFR/DFH MARINE...IMR/LFR/DFH TIDES/COASTAL FLOODING...DFH/LFR

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