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 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 041414 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 914 AM EST WED MAR 4 2015 .SYNOPSIS...
-- Changed Discussion --
A COLD FRONT WILL CROSS THE REGION TODAY AND TONIGHT. HIGH PRESSURE BUILDS OVERHEAD FRIDAY...THEN PERSISTS THROUGH THE WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
SFC ANALY DEPICTS A CPL OF BNDRYS IN THE PRES FIELDS THIS MRNG. THE FIRST ONE RUNS FM BALT/DC TO CHO...THEN HEADS WSWWD ACRS TN TO ARKANSAS. THIS BNDRY HAS LLVL THERMAL SUPPORT. THE LATTER STRETCHES ACRS NW PA AND NRN OH. THE UPR JET DYNAMICS LIE HERE. REGIONAL RADAR THIS MORNING ALREADY SHOWS THE DYNAMICAL...HIGH MOISTURE CONTENT FRONTAL ZONE SAGGING OUR WAY. THERES PLENTY OF MSTR W OF THE APLCNS ATTM...AND WL NEED TO MONITOR HOW MUCH OF THIS CAN HOP THE MTNS. IN SHORT...TODAY WILL FEATURE OCCASIONAL ROUNDS OF RAIN...MOST PREVALENT ACROSS THE NORTHERN HALF OF THE CWA. WILL KEEP AN EYE ON RAIN TOTALS...ESPECIALLY IN THE HIGHLANDS WHERE TEMPERATURES HAVE WARMED AND THE HEAVIEST RAIN WILL FALL. IN-SITU WEDGE WILL HOLD TEMPERATURES IN THE 40S ACROSS MUCH OF AREA. GOING FCST HAS GOOD LAMP SUPPORT. NO TEMP CHGS ANTICIPATED ATTM.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
-- Changed Discussion --
SYNOPTIC PTTN FM LTST GDNC RUNS SEEM TO BE SIMLR TO THOSE YDA. ONLY ADJUSTMENTS BASED ON SUBTLE THERMAL DIFFS. KEY FACTORS ARE A SLGTLY SLOWER TIMING AND HIER QPF VALUE. BASED ON THAT...THE MIDNIGHT SHIFT TRANSITIONED THE WINTER STORM WATCH TO A WARNING FOR MOST OF THE CWFA. THE SRN FRINGE OF THE AREA IS THE EXCEPTION DUE TO A LONGER PD OF TIME IN RAIN AND SLEET. THE BNDRYS /MDL GDNC DOESNT DO A GOOD JOB DISTINCTLY RESOLVING BOTH OF THEM/ WL CONT SLIDE SWD TNGT...ALLOWING THE ARCTIC AMS FM THE GRTLKS TO OVERSPREAD THE AREA. MEANWHILE...A SATD MSTR STREAM WL CONT SPREADING ENEWD...OVERRIDING THE COLDER AMS. DYNAMICS WL BE FUELED BY THE RRQ OF THE UPR JETMAX AS WELL AS LLVL BAROCLINICITY. ALL OF THIS SUPPORTS A TRANSITION FM RA TO PL AND THEN TO SNW. FCST BASED ON AN ENSEMBLE APPROACH...WHICH SUGGESTS A PD OF FVRBL DENDRITIC GROWTH AS WELL AS FGEN FORCING IN A CORRIDOR BHD THE SN/PL TRANSITION. THATS THE JUSTIFICATION FOR RAISING SNW TTLS ACRS N-CENTRAL MD/ERN WVA/NRN SHEN VLY...AS THESE FEATURES WL COINCIDE W/ SNWFL THE LONGEST. SUFFICIENT COLD AIR TO SUPPORT SNW WL REACH THE SRN EDGE OF THE CWFA BY AFTN. WL BE MAKING THE WRNG/ADVY DECISION FOR THE SRNMOST 5 CNTYS ONCE 12Z GDNC ARRIVES. TAIL END OF SNOW THURSDAY EVENING IS A FEW MORE TENTHS INCH FOR SRN MD BEFORE TAPERING OFF. SKIES CLEAR LATE IN THE NIGHT WITH HIGH PRESSURE QUICKLY BUILDING OVERHEAD. GUSTY NW FLOW (AROUND 20 MPH) FOLLOWS THE COLD FRONT. WIND CHILLS REACH ZERO ACROSS THE CWA WITH WIND CHILL ADVISORIES LIKELY OVER PORTIONS WEST OF INTERSTATE 95. AREAS WEST OF INTERSTATE 95 SHOULD DECOUPLE BEFORE SUNRISE WHICH WILL ALLOW FOR SINGLE DIGIT MIN TEMPS...TEENS EAST. SUNNY FRIDAY UNDER HIGH PRESSURE WITH TRANQUIL CONDITIONS AND MAX TEMPS MID TO UPR 20S DUE TO LITTLE MIXING AND FRESH SNOW.
-- End Changed Discussion --
&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... ONE OF THE LONGEST CONSISTENT WARMING PATTERNS IN AWHILE SATURDAY THROUGH MIDDLE OF NEXT WEEK AS VERY BROAD EAST COAST TROUGH SLOWLY DEAMPLIFIES. WELCOME CALM WEATHER PATTERN AS THE SUBTROPICAL RIDGE BUILDS INTO THE SERN CONUS. A FEW DEGREES WARMER ON MAX TEMPS EACH DAY IN SWLY FLOW...LOW 40S FOR SATURDAY...50S BY MONDAY...60S...MAINLY SOUTH OF DC MONDAY THROUGH WEDNESDAY. UNCERTAINTY DUE TO CLOUD COVER IN THE MIDDLE OF NEXT WEEK PREVENTED A BOLDER FORECAST OF MID 60S SOUTH/MID 50S NORTH BY WEDNESDAY...AS OF NOW IT IS AROUND 60F SOUTH AND AROUND 50 NORTH. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
VFR CONDS PREVALENT ACRS THE TERMINALS ATTM...BUT W/ PATCHES OF IFR. SOLID FLGT RESTRICTIONS WL ARRIVE FOR THE AFTN PUSH...W/ CONSISTENT AOB IFR COINCIENT W/ A TRANSITION TO SNW AFTR MIDNGT. AOB IFR SHUD CONT THRU THE DAY THU. CONDS QUICKLY IMPROVE TO VFR THURSDAY EVENING FROM NW TO SE WITH NW GUSTS AROUND 20 KT. SINGLE DIGITS MIN TEMPS THAT NIGHT FOR MOST OF THE AREA. HIGH PRESSURE BUILDS OVERHEAD FRIDAY WITH VFR/TRANQUIL CONDS. SWLY FLOW AND MORE HIGH PRESSURE THEN THROUGH THE WEEKEND.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
ALL WNDS AOB 10 KT ATTM. A TRANSITION TO NNWLY FLOW WL OCCUR LATER TDA OR TNGT. WNDS WL INCREASE THEREAFTR...W/ SCA CONDS FOER THE LATTER PART OF THE NGT INTO THU NGT. SCA LIKELY TO EXTEND INTO FRIDAY BEFORE HIGH PRESSURE BUILDS OVERHEAD. HIGH PRESSURE THEN THROUGH THE WEEKEND WITH SWLY FLOW DEVELOPING FRIDAY NIGHT.
-- End Changed Discussion --
&& .HYDROLOGY...
-- Changed Discussion --
THERE HAS BEEN NOTEABLE SNOWMELT ACRS THE AREA THUS FAR. ADD IN RAINFALL UP TO A HALF-INCH...AND RIVERS IN THE UPR PTMC BASIN HV EXPERIENCED SGFNT W/IN BANK RISES. STILL DO NOT XPCT FLOODING... BUT WL CONT TO MONITOR CLOSELY. AT THIS RATE...RAINFALL MAY REACH 1-2 INCHES. SOME COMPLICATING FACTORS TO KEEP IN MIND...IF THE CHANGEOVER FROM RAIN TO WINTRY PRECIP THIS EVENING OCCURS LATER THAN EXPECTED... CONCERNS MAY BECOME HEIGHTENED. TRENDS HV BEEN SUGGESTING A LATER CHANGEOVER. ALSO MANY OF OUR AREA STREAMS ARE COVERED WITH ICE OR EVEN PARTIALLY FROZEN. THESE EFFECTS WILL HAVE TO BE MONITORED FOR A POTENTIAL ROLE IN AFFECTING RUNOFF. LASTLY...AS WE SAW WITH THE RECENT RAIN/ICE/MINOR SNOWMELT...ANY AMOUNT OF LIQUID PRECIPITATION STANDS A GOOD CHANCE OF CAUSING MINOR POOR DRAINAGE FLOODING...AS NORMAL DRAINAGE PATTERNS MAY BE BLOCKED BY PLOWED SNOW.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 9 PM EST THURSDAY FOR DCZ001. MD...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY FOR MDZ003-501-502. WINTER STORM WARNING FROM 10 PM THIS EVENING TO 7 PM EST THURSDAY FOR MDZ004>006-011-503>508. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 9 PM EST THURSDAY FOR MDZ013-014-016-018. WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY EVENING FOR MDZ017. VA...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY FOR VAZ028-503-504. WINTER STORM WARNING FROM 10 PM THIS EVENING TO 7 PM EST THURSDAY FOR VAZ025>027-029>031-040-501-505>508. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 9 PM EST THURSDAY FOR VAZ038-039-050>055-502. WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY EVENING FOR VAZ036-037-056-057. WV...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY FOR WVZ050>052-055-501>506. WINTER STORM WARNING FROM 10 PM THIS EVENING TO 7 PM EST THURSDAY FOR WVZ053. MARINE...SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR ANZ530>543.
-- End Changed Discussion --
&& $$ SYNOPSIS...BAJ/ADS/HTS NEAR TERM...ADS/HTS SHORT TERM...HTS/BAJ LONG TERM...BAJ AVIATION...HTS/BAJ MARINE...HTS/BAJ HYDROLOGY...HTS/JE

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