Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 061447 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1047 AM EDT MON JUL 6 2015 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH INTO THE AREA TODAY AS A LOW PRESSURE SYSTEM WEAKENS OVER THE REGION. HIGH PRESSURE BRIEFLY BUILDS TUESDAY. A WEAK COLD FRONT WILL THEN ENTER THE REGION TUESDAY NIGHT...THEN LINGER THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... 14Z SFC ANALYSIS SHOWING WEAK WARM FRONT EXTENDING ACROSS THE AREA WHILE UPPER LVL TROUGH SLOWLY PUSHES EAST INTO THE MID ATLANTIC. LATEST REFLECTIVITY SHOWING SPOTTY SHOWERS POPPING UP ALONG FRONTAL BOUNDARY WITH SUPPORT FROM WEAK VORT MAX PLACED OVER WESTERN MD. EXPECTING MOSTLY DRY CONDITIONS FOR MOST OF THE AREA THRU THE MORNING...WITH INCRSG COVERAGE OF CONVECTION AFTR 18Z. AFTR 18Z...FRONTAL BOUNDARY REMAINS NEARLY STATIONARY NEAR THE MASON-DIXON LINE INTO THIS EVENING. AS THE UPPER LVL TROUGH PIVOTS EAST...EXPECTING SHOWERS AND TSTMS TO FORM WEST OF THE BLUE RIDGE AND ALONG THE FRONT OVER MD...PUSHING EAST LATE AFTN AND INTO THE EVENING. CONCERNING SVR THREAT...MOST OF THE AREA REMAINS IN A MARGINAL RISK WITH DAMAGING WINDS...HEAVY RAINFALL AND EVEN AN ISO TORNADO PSBL. THINKING THE BEST TIMING WILL BE BTW 18-02Z TO MAXIMIZE DIURNAL HEATING. CLOUDS LOOKING TO NOT SCATTER OUT NEARLY AS ORIGINALLY THOUGHT...BUT ENOUGH DESTABILIZATION SHOULD STILL OCCUR TO AID IN TSTM DEVELOPMENT. STRONG SURGE OF MOISTURE ON GOING...WITH PWATS FROM 12Z SOUNDING AROUND 1.7 INCHES. WITH THE GENERAL FLOW FROM THE S...COULD SEE TRAINING CELLS THIS AFTN...AND WITH THE HIGHER MOISTURE...HEAVY RAIN IS EXPECTED. HOWEVER...WITH THE SCT NATURE OF THE STORMS...ANY FLOODING/FLASH FLOODING WILL BE LOCALIZED. BACKING WINDS RIGHT AROUND THE FRONTAL BOUNDARY WILL ALSO HEIGHTEN THE TORNADO DEVELOPMENT THREAT...MAINLY LATE AFTN. THE AXIS OF THE REMNANT UPR TROUGH SHIFTS INTO THE AREA TONIGHT... SHUNTING ACTIVITY EAST. KEPT SOME POPS NEAR THE CHESAPEAKE THROUGH THE NIGHT. MIN TEMPS MILD...UPR 60S WEST OF THE BLUE RIDGE...LOW 70S EAST. TUESDAY...SWLY FLOW OVER THE AREA WITH A SWATH OF 20C 850 TEMPS SUGGEST MID 90S IF THE CLOUDS CAN CLEAR. WENT GENERALLY LOW 90S...AN INCREASE PREVIOUS FORECAST. DEWPOINTS IN THE MID/UPR 60S WOULD ADD A FEW DEGREES IN A HEAT INDEX. ISOLATED TSTMS NEAR THE BAY BREEZE AND IN THE TERRAIN. OTW...NVA BEHIND THE TROUGH LIMITS ACTIVITY. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... LOW LEVEL MOISTURE WILL INCREASE FROM THE SOUTH TUESDAY NIGHT AHEAD OF A COLD FRONT FORECAST TO CROSS THE REGION ON WEDNESDAY. THE FRONT WILL LIKELY BE ACCOMPANIED BY INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS ESPECIALLY DURING THE AFTERNOON AND EARLY EVENING. HIGH TEMPERATURES ON WEDNESDAY WILL LIKELY REACH THE LOW TO MID 80S WEST TO THE UPPER 80S TO LOWER 90S EAST OF THE BLUE RIDGE. FRONT WILL PUSH OFFSHORE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING AND HIGH PRESSURE WILL BUILD IN BRIEFLY FOR THE FIRST PART OF THURSDAY. THURSDAY WILL BE SLIGHTLY COOLER BUT THERE WILL STILL BE A CHANCE FOR SCATTERED SHOWERS/STORMS DURING THE AFTERNOON AND EVENING. && .LONG TERM /FRIDAY THROUGH SUNDAY/... MEDIUM TO LONG RANGE PATTERN FEATURES A RIDGE OF HIGH PRESSURE OVER THE SOUTHEAST U.S WITH A SERIES OF WEAK UPPER DISTURBANCES CROSSING THE REGION THROUGH THE WEEKEND. THIS WILL LEAD TO AT LEAST OF CHANCE FOR SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY. HIGH TEMPERATURES IN THE 80S TO NEAR 90 CAN BE EXPECTED. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... BKN-OVC MVFR-VFR CIGS CURRENTLY. EXPECTING CIGS TO BECOME ALL VFR...AROUND 4-5 KFT...FOR THE AFTN. TSTMS MAINLY PSBL 18-02Z...THOUGH WILL BE SCT IN NATURE. SOME OF THE STORMS...ESP NEAR DC/BALTIMORE...COULD RESULT IN STRONG WINDS IN EXCESS OF 40 KTS AND HEAVY RAINFALL. THE STORMS WILL ALSO DROP CONDITIONS TO SUB-VFR AND PSBL IFR AT TIMES. LINGERING PCPN THIS EVENING...CLEARING FROM WEST TO EAST OVERNIGHT. VFR CONDITIONS FOR TUESDAY. MOSTLY VFR CONDITIONS EXPECTED TUESDAY NIGHT THROUGH FRIDAY...HOWEVER...AFTERNOON AND EVENING SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EACH DAY WHICH COULD LOCALLY REDUCE VISIBILITIES BELOW VFR. PATCHY OVERNIGHT FOG MAY ALSO BE POSSIBLE. && .MARINE... WARM FRONT LIFTS INTO THE AREA TODAY WITH SLY CHANNELING WITH 20 KT GUSTS OVER SRN MD BAY WATERS LATE THIS AFTERNOON INTO THE OVERNIGHT WHERE THERE IS AN SCA. 10 TO 15 KT ELSEWHERE. FLOW SHIFTS SWLY TONIGHT AND 15 KT SWLY FLOW EXPECTED TUESDAY...WILL NEED TO WATCH FOR SOME 18 KT GUSTS ACROSS THE WATERS. WINDS ARE EXPECTED TO REMAIN BELOW SCA FOR MUCH OF THE MEDIUM TO LONG RANGE PERIOD. OCCASIONAL AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE THROUGH THE WEEKEND. ANY STORM THAT DOES DEVELOP COULD PRODUCE GUSTY WINDS...LIGHTNING AND BRIEF HEAVY DOWNPOURS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EDT TUESDAY FOR ANZ533-534-537-543. && $$ SYNOPSIS...KRW NEAR TERM...BAJ/SEARS SHORT TERM...BAJ/KRW LONG TERM...KRW AVIATION...BAJ/KRW MARINE...BAJ/KRW

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