Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 010729 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 329 AM EDT SUN MAY 1 2016 .SYNOPSIS...
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A WEDGE OF HIGH PRESSURE WILL REMAIN ACROSS THE NEW ENGLAND AND MID ATLANTIC COAST TODAY. LOW PRESSURE WILL TRACK ACROSS PENNSYLVANIA TONIGHT WITH ITS ASSOCIATED COLD FRONT MOVING THROUGH THE AREA EARLY MONDAY. AN UPPER LEVEL LOW PRESSURE SYSTEM IS EXPECTED TO BECOME STATIONARY OVER THE NORTHEASTERN U.S. FOR THE SECOND HALF OF THE WEEK.
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&& .NEAR TERM /THROUGH TONIGHT/...
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THTE RDG ADVCG ACRS CWFA ATTM. SYNOPTIALLY...HIPRES RDG FM NEW ENGLAND STILL ASSERTING ITS INFLUENCE ACRS THE MID ATLC. THIS IS EVIDENT INTHE PCPN PTTN AS WELL...SINCE HEAVIER PCPN RATES STILL NEAR THTE AXIS...ALONG AND W OF THE APLCNS. LCLLY...RAFL HAS BEEN MAINLY LGT. GDNC CONTG ITS TREND OF SLOWLY MVG THE STREAM OF RICH MSTR EWD. BASED ON RAP/HRRR/WRF-ARW4...PDS OF RA SHUD CONT TIL ABT 16-18Z. HV USED CAT TO LKLY POPS DURING THIS TIME...THAT GRDLY TAPER RAFL OFF AS ISENT RDG SHIFTS EWD. THE PRESENCE OF CLDS/RAFL SHUD KEEP ATMOS STBL THRU THIS TIME. SCENARIO BECOMES A LTL MORE MUDDLED FOR THE AFTN-EVE HRS. BELIEVE THERE WL BE A BREAK IN THE PCPN BEFORE ADDTL DIURNALLY DRIVEN SHRA DVLP AS WAA/UPGLIDE CONTS. GDNC QUITE A BIT MORE RESERVED WRT INSTBY...GIVING MORE CREEDENCE TO CAD WEDGE. CONSIDERING NOT JUST MDL BIAS BUT ALSO PCPN TIMING... THIS MAKES SENSE. HWVR... LAPSE RATES/SHEAR W OF THE WEDGE WL BE QUITE STRONG. WHILE THUNDER RISK FOR CWFA HAS BEEN TRIMMED OVERALL...STILL HV LKLY THUNDER GNLY IN SAME AREA WHERE SPC PLACED MRGL RISK OF SVR /APLCNS AS WELL AS PARTS OF AUGUSTA AND NELSON CNTYS/. THUNDER RISK TAPERS OFF TO THE NE. DONT THINK METRO BALT WL SEE ANY THUNDER...NOT EVEN ELEVATED. HWVR...STORMS DVLPG IN THE UNSTBL AMS WL OVERRUN THE COOL LLVLS AND GRDLY STRATIFY. THIS PROCESS WL CONT MUCH OF THE NGT. LOPRES TRACKING INTO PA TNGT WL DROP A CDFNT TWD AREA. THIS SUPPORT WL KEEP PCPN GOING PAST THE TYPICAL DIURNAL CNVCTV PD. IN TERMS OF TEMPS...WE/VE BEEN UNDERCUTTING MOS FOR NE MD...AND WL CONT THAT PRACTICE TDA. IN CONTRAST...AM A CPL DEGF ABV ACRS CHO AND THE PTMC HIGHLANDS...WHICH HAS BEST CHC AT ENTERING THE WARM SECTOR.
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&& .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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LOPRES IN PA WL TRACK TWD NEW ENGLAND MON MRNG...WHICH WL PUSH A CDFNT THRU THE AREA. WL BE KEEPING POPS GOING FOR THE MRNG HRS. BELIEVE THERE SHUD BE SOME SUBSIDENCE IN WLY FLOW BHD FNT...AND WL ATTEMPT TO PRESERVE THE DRY PD /PT-MOSUNNY SKIES/ IN FCST. HWVR...THERE IS GREATER DOUBT AS TO HOW FAR SE THE FNT WL BE ABLE TO TRAVEL BEFORE STALLING OUT. WAVES OF WK LOPRES WL BE SHOOTING THRU THIS ZONE... SO THE FRNTL POSN WL BE CRITICAL. FIRST GOOD OPPORTUNITY OF SUCH COMES MON EVE. CONSEQUENTLY POPS HV BEEN RAISED FM PREV FCST. HV ALSO ADDED THUNDER IN LIGHT OF DAY 2 SPC OUTLK. HWVR...FCSTG SUCH IMPULSES MORE THAN A DAY IN ADVC CAN BE PROBLEMATIC AT TIMES...AND THUS HV A LWR OVERALL CONFIDENCE IN SOLN. ADDTL WAVES OF LOPRES CROSS AREA TUE-TUE NGT. ITS TOUGH TO PIN DOWN TIMING DETAILS IN THIS PTTN. THUS...ONLY BROAD STROKES WERE PLACED IN DATABASE. SHUD BE ABLE TO GET QUITE WARM MON IN WAKE OF FROPA PROVIDED CNVCTN HOLDS OFF. HV TAKEN THAT RTE IN MAXT GRID. THERE WL BE MUCH LESS OF A DIURNAL RANGE ONCE SHRA RTN.
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&& .LONG TERM /WEDNESDAY THROUGH SATURDAY/...
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THE XTND FCST IS SOMEWHAT OF A BKN RECORD COURTESY OF THE UPR LVL PATTERN W/ A LARGE RDG/OMEGA BLOCK OVR THE ROCKIES AND A CLOSED LOW OVR THE NERN U.S. WED MAY BE THE BEST DAY OF THE XTND PD AS ONE LOW PULLS OUT TO THE NE FM THE MID ATLC...BUT THERE`LL STILL BE THE PSBLTY OF RW. HIGHS WED 65-70. AFTR THAT AN UPR LVL SHORT WV DIVES DOWN INTO THE ALREADY-PRSNT UPR LOW...CAUSING INTENSIFICATION AND THE LOW TO CUT OFF...BCMG STATIONARY OVR THE NERN U.S. THU-SAT. XTNSV CLD CVR W/ RW...HIGHS IN THE M60S..LOWS IN THE MU40S.
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&& .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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WHILE FLGT CONDS HV GNLY HELD IN VFR RANGE THUS FAR...IAD HAS DROPPED INTO IFR. BELIEVE THAT CONDS OVERALL WL DETERIORATE...BUT HV LMTD CONFIDENCE IN WIDESPREAD IFR BEFORE DAWN. ONCE WE GET INTO THE DAYTIME HRS...CONDS SHUD CONT TO WORSEN AS RAFL CONTS. DO HV IFR FM DAYBREAK INTO MIDDAY. THERE SHUD BE IMPRVMNT TAFTN AS RA DEPARTS...BUT QSTN WL BE HOW MUCH. DONT THINK IT/LL BE MUCH INVOF BWI /THEY STAY IN STBL WEDGE WITH PLENTY OF LLVL MSTR/...WHILE SUSPECT WE/LL REACH VFR /WARM SECTOR/ AT CHO. IN THAT WARM SECTOR...SCT TSRA MAY DVLP...WHICH WL STBLZ AS THEY HEAD NE. RESTRICTIONS WL CONT THRU TNGT. CFP MON MRNG. SHUD ACHIEVE VFR AFTER THAT POINT. HWVR...ADDTL SHRA /TSRA?/ MON NGT...WHICH WL CONT PERIODICALLY THRU TUE NGT. THESE MAY YIELD ADDTL FLGT RESTRICTIONS. VFR CONDS WED OUTSIDE OF RW WED...THEN OVC SKIES THU W/ RW...PSBLY DROPPING INTO MVFR RANGE.
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&& .MARINE...
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SE WINDS 10-15 KT ATTM...WHICH SHUD BE THE STORY FOR MUCH OF TDA. MAY SEE SOME VEERING S...SPCLY FOR MID BAY/LWR PTMC...BUT SPDS SHUD BE UNDER 10 KT. CFP MON...WHICH WL TRANSITION WIND TRAJ TO WLY...BUT FNT WEAK AND WONT CLEAR WATERS BY MUCH...SO DONT SUSPECT WE/LL SEE A SURGE BHD FNT. THUS...NO SCA ANTICIPATED THRU TUE. NO PROBS FORESEEN ON THE WATERS WED OR THU OTHER THAN RW.
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&& .TIDES/COASTAL FLOODING...
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WATER LVLS RUNNING ABOUT 3/4 FT TO 1 FT ABV ASTRO NORMALS. LATEST ETSS GDNC SUGGESTS TIDES TODAY WILL COME IN UNDER MINOR FLOOD THRESHOLDS...BUT FOR SGSM2 AND ANNAPOLIS...ITS ONLY BY A COUPLE OF INCHES. WILL CONTINUE TO MONITOR...AS THERE IS ROOM FOR ERROR. ELEVATED WATER LEVELS WILL CONTINUE TONIGHT INTO EARLY MONDAY... BUT ANOMALIES SHOULD FALL CLOSER TO NORMAL LATER MONDAY.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ HTS/WOODY!

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