Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Graphics & Text | 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 272151 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 551 PM EDT FRI MAR 27 2015 .SYNOPSIS...
-- Changed Discussion --
AN UPPER-LEVEL TROUGH WILL SLOWLY MOVE ACROSS THE EASTERN UNITED STATES TONIGHT AND SATURDAY MORNING. HIGH PRESSURE WILL BUILD OVERHEAD SUNDAY. SEVERAL WEAK FRONTS WILL CROSS THE AREA NEXT WEEK.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --
HV RMVD SOME OF THE LOW CHC POPS FOR THE RMNDR OF THE DAY IN THE CENTRAL PART OF THE CWA. AS CAN BE SEEN ON RGNL RDR THE BEST CHC FOR PCPN (R) IS IN THE E IN ASSO W/ THE CSTL LOW. IF PCPN DOES HAPPEN OVRNGT BLV IT WL BE SCT/LGT IN NATURE. WHILE WE HV CHC SW/RW IN THE FCST FOR SAT MRNG THRU MID AFTN THIS IS THE TIME OF YR WHERE LO LVL INSTABILITY COUPLED W/ A COLD POOL ALOFT CAN PRODUCE GRAUPEL. PRVS DSCN... H5 TROF AXIS WL DROP INTO CWFA AFTR MIDNGT AND CROSS THRU ELY/MID AFTN. THIS TIMING A PINCH QUICKER THAN PRVS PROGS. CAA WL BE ONGOING FM TAFTN THRU TMRW AFTN...W/ H8 TEMPS BTTMG OUT ARND -10 TO -14C. HWVR...BEST INSTBY AND PVA MIGHT NOT BE COINCIDENT...WHICH MAKES ORGANIZED PCPN LESS LKLY. AM LEANING MORE TWD DYNAMIC FORCING MECHANISMS FOR PCPN PRODUCTION...WHICH SUGGEST THAT POP CHCS PREFERRED OVNGT INTO ELY MRNG CENTRAL VA INTO THE PTMC HIGHLANDS... AND MRNG/MIDDAY HRS I-95 CORRIDOR/CATOCTINS-NRN BLURDG/HGR-MRB AREA. MD MAY BE A BIT MORE SUSCEPTIBLE INTO ELY AFTN AS LTMD INSTBY BUILDS IN DAYTIME HEATING. THAT SAID...MSTR WL BE LIMITED AND HIT-OR-MISS IN NATURE-- NOT WORTHY OF MORE THEN CHC POPS. DUE TO COLD AIR ALOFT /AND TO A CERTAIN EXTENT AT THE GRDN FOR THOSE SITES THAT SEE ANYTHING DURING THE AM/...PCPN THAT MAKES IT TO THE GRND STANDS A GOOD CHC TO REACH AS SNOW PRIOR TO MELTING BUT THERE WUD BE TOO LTL TO BE CONCERNED ABT ACCUMS. HIPRES BUILDS DURING THE MID-LT AFTN...WHICH WL ALLOW FOR SKIES TO BEGIN CLRG. THUS DONT HV ANY POPS FOR THE LATTER HALF OF THE AFTN. WINDS WL BE GUSTY ALL DAY...AND THAT WL CONT TO NIGHTFALL. TOP OF MIXED LYR CONTAINS 25 KT...WHICH GIVES A REASONABLE IDEA OF THE GUST POTL. TEMP GDNC FAIRLY WELL CLUSTERED AND CONSISTENT W/ GOING FCST. AS SUCH...HV TAKEN A BLEND TO IRON OUT ANY CONSISTENCIES THAT MAY RESIDE. THAT MEANS MIN-T MID TEENS-20S MTNS AND 30-35F CSTL PLAIN. MAXT MID 30S-MID 40S. SHADED TEMPS ACRS THE NORTH AND WEST DOWN BY A DEGF OR TWO TO ACCT FOR IMPACT OF CAA.
-- End Changed Discussion --
&& .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... AFTER A DAY IN WHICH IT MAY FEEL LIKE WINTER IS STILL HERE - ON SAT...SUNDAY WILL BE A SLIGHT REBOUND BACK TOWARD MORE AVERAGE CONDITIONS. ULTIMATELY WE`LL MISS THE MARK IN TEMPS OF AVG HIGHS ON SUN BY A SOLID 10F DEG OF SO...BUT LIGHT WINDS AND MOSTLY CLEAR SKIES WILL AT LEAST SUPPLEMENT THE COOLER TEMPS. A WEAK UPPER RIDGE WILL BE RESPONSIBLE FOR OUR QUIET WX CONDITIONS ON SUN...BUT WITH A STILL VERY ACTIVE JET STREAM - MULTIPLE UPPER DISTURBANCES REMAIN IN THE QUEUE FOR PASSAGE OVER THE COMING WEEK. FAST ON THE HEELS OF THE UPPER RIDGE WILL BE RELATIVELY LARGE BUT FAIRLY MOISTURE-STARVED UPPER WAVE FROM THE GREAT LAKES REGION. OVERNIGHT LOWS WILL AGAIN DROP DOWN INTO THE M-U30S BUT W/ A LIGHT SLY WIND OUT AHEAD OF THE APPROACHING DISTURBANCE...THESE CONDITIONS WILL BE MODERATED AND PREVENT MOST AREAS FROM REACHING THE FREEZING MARK. A WEAK COLD FRONT WILL ARRIVE EARLY MON MRNG...QUICKLY PASSING ACROSS THE REGION AND MAINLY JUST SWITCHING THE SFC WIND DIRECTION FROM SLY TO WLY...ALSO EFFICIENTLY MIXING DOWN SOME GUSTY WINDS FOR THE DAYTIME HRS. WEST WINDS OF 20-30MPH EXPECTED W/ LOCALLY HIGHER GUSTS...CREATING SOME DOWNSLOPING AND A SUPPLEMENTAL TEMP INCREASE IN THE LEE OF THE APLCNS/BLUE RIDGE. HIGHS OVER THE WRN HALF OF THE AREA WILL LIKELY JUMP INTO THE M-U50S...THOUGH NOVA THE PIEDMONT MAY SEE SOME M-U60S BY LATE AFTN W/ CLEARING SKIES AFTER THE EARLY MRNG FRONTAL PASSAGE. && .LONG TERM /MONDAY THROUGH FRIDAY/... THERE MAY BE ENOUGH MOISTURE AVAILABLE OUT OF LOW PRESSURE SYSTEM OVER GREAT LAKES FOR WEAK PVA TO TRIGGERS A LIGHT RAIN SHOWER OR TWO TUESDAY. GREAT LAKES LOW WILL PASS TO OUR NORTH. TEMPERATURE PROFILE SUPPORTS MIXED PRECIPITATION IF ANY OCCURS LATE TUESDAY AND EARLY WEDNESDAY. WEAK PVA IN ZONAL FLOW WILL SUPPORT RAIN AHEAD OF A WEAK FRONTAL BOUNDARY DURING THE LATTER HALF OF THE WEEK. THIGHTNING GRADIENT BETWEEN APPROACH FRONT AND OFFSHORE RIDGE WILL PRODUCE S-SW WINDS 10-15 KTS THURSDAY. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
VFR CONDS THRU SAT. RW/SW/IP PSBL DURG MRNG HRS SAT ALNG W/ BRIEF GUSTY WINDS. WINDS SHUD BE GUSTY BHD TROF...FROM THE NW ARND 20-25 KT. SUSTAINED WINDS LKLY IN THE TEENS...NOT PROVIDING ENUF SEPARATION TO EXPLICITLY INCL GUSTS IN TAF. NO HAZARDOUS WX CONDS EXPECTED FROM LATE SAT INTO MON...OUTSIDE OF SOME BREEZY CONDS ON MON AFTN BEHIND A COLD FRONT. BOUNDARY LAYER WINDS IN THE 30-40KT RANGE W/ SOME 20-25KT GUSTS AT THE SFC DURING THE DAYTIME HRS.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
WINDS PICKING UP TONIGHT...ALTHO BETTER MIXING MAY NOT REACH THE NARROWER WATERS TIL SUNRISE TMRW. HV MADE APPROPRIATE ADJUSTMENTS TO THE DATABASE. ONCE IT BEGINS...TOP OF MIXED LYR CONTAINS 25 KT...WHICH GIVES A REASONABLE IDEA OF THE GUST POTL. SCA FOR ALL WATERS SAT. BREEZY NW WINDS WILL CONTINUE OVER MUCH OF THE WATERS SAT NIGHT...ESPEC THE MAIN STEM OF THE MD CHES BAY. A SLOW STEADY WIND DROP OFF ON SUN AS HIGH PRESSURE MAKES A BRIEF APPEARANCE BEFORE ANOTHER COLD FRONT ON MON MRNG. BEHIND THE FRONT...WEST WINDS WILL AGAIN PICK UP INTO SOLID SCA RANGES FOR THE DAYTIME HRS MON.
-- End Changed Discussion --
&& CLIMATE... OUR AREA IS IN THE MIDST OF A LARGE SWING IN TEMPERATURES. AHEAD OF A COLD FRONT ON THURSDAY AFTERNOON (MARCH 26TH)...THE REGION SAW THE WARMEST TEMPERATURES OBSERVED SINCE LATE OCTOBER 2014. SITE...3/26/15 MAX T...WARMEST SINCE..... DCA.......77 F.......10/28/2014 (80 F)... BWI.......74 F.......10/28/2014 (80 F)... IAD.......74 F.......10/28/2014 (82 F)... SUNDAY MORNING (MARCH 29TH)...LOW TEMPERATURES MAY APPROACH RECORD MINIMUM VALUES FOR THE DATE. SITE...3/29 RECORD MIN T... DCA......18 (1923)......... BWI......18 (1923)......... IAD......20 (1982)......... && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ530>534- 537>543. SMALL CRAFT ADVISORY FROM 8 AM TO 6 PM EDT SATURDAY FOR ANZ535- 536. && $$ UPDATE...WOODY!/DFH PRVS...HTS/GMS

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