109 FXUS61 KLWX 192006 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 306 PM EST Sat Jan 19 2019 .SYNOPSIS... A strong storm system will move northeastward across the region tonight. Arctic high pressure will gradually build across the region Sunday through Tuesday. A slow moving cold front will slide into the region Wednesday, with another strong storm system possibly moving across the region late in the week. && .NEAR TERM /THROUGH SUNDAY/... Latest surface analysis depicts a strengthening low pressure near Memphis, Tennessee. A warm front extends eastward toward the Carolina coast, with a cold front extending southwest into the Gulf. A second front, nearly stationary, extends northeast from the low across Kentucky and West Virginia, then straddles the PA/MD line eastward towards Atlantic City. This front lying just to the north is what we thought would bring air cold enough to support some wintry weather today, but this has not yet come to pass. Given that precip is moving in and the cold air remains north, it is increasingly likely that most areas will see limited if any wintry weather. Have mostly scaled back snow and ice accumulations, with ice now mostly limited to higher elevations except in western MD and the west end of the eastern WV panhandle. This has meant a general scaling back of the winter headlines, with most of the warning converted to advisory and much of the previous advisory now cancelled. That said, there can still be some mixed precip as the main mass of moisture moves in, but with temps now in the mid-upper 30s region wide, accumulations will be limited to non-existent. Warm front along the Carolina coast will try to nudge northward into southern MD later this evening into the overnight as the low to the southwest approaches, which should allow temps to rise slowly but steadily in these areas. The actual surface low may make a jump of some sort as it crosses the mountains, with a new center reforming near the DC/Baltimore region. Will have to watch overnight for locally heavier rain near the new low track across the I-95 corridor, as well as potential for some sort of convective line south of it in the "warm" sector. Might also start to get some cold air draining back south as this center jump occurs, which could allow some places which are above freezing now in northern MD and eastern WV to drop below before the precip ends. The system pulls quickly to the northeast early Sunday, with precip pulling out near or just after dawn, mostly in the form of rain. Strong pressure gradient developing on the back side of the low will likely lead to widespread gusts of 40-45, perhaps 50 mph, so have issued wind advisory for most of the CWA on Sunday. Otherwise, the theme of the day will be winter's return as cold air rushes back into the region. Temps which will start out in the fairly mild 40s in the metro will end up in the 20s by the end of the day, with whatever liquid remains likely freezing up. Perhaps not quite a "flash" freeze technically, but definitely a hazard. Further west will not start out so lucky, with temps likely stuck in the 30s most of the night, but they too will end up well below freezing by day's end. Wind chills will also plummet, with readings likely into the single digits by nightfall. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... Low pressure will continue slowly moving away Sunday night through Monday night as arctic high pressure slowly builds in. This will keep the winds from diminishing rapidly, with only a slow decline. Combined with bitterly cold arctic air, wind chill advisories will almost certainly be needed across most of the CWA, and its possible some of the high mountains out west might need a wind chill warning. The northwest winds will likely also result in some snow showers in the upslope areas, but accumulations will be minimal. Snow showers should abate Monday as the gradient relaxes slowly and high pressure moves closer. Monday promises to be the coldest day so far this winter, with temps struggling to reach 20, and many places likely failing to do so. Monday night will also be cold, but with the high moving overhead, winds should slack off considerably, so wind chills likely won't be nearly as bad. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Changeable weather expected through next week with very cold conditions early giving way to moderating temperatures with increasing precipitation mid-week, followed by falling temperatures again by the end of the week. Strong 1035-1040mb high pressure will be positioned overhead Tuesday morning, leading to near ideal radiational cooling conditions with morning lows likely bottoming out in the single digits and teens for many locations, with some sub-zero air temperatures likely. The air mass will however bounce in and out quite quickly, with south/southwest flow developing during the day Tuesday. Dry conditions still expected with highs rebounding in the 30s. The next system will then rapidly be moving through the eastern Great Lakes Tuesday night into Wednesday with its attendant cold front pushing eastward towards the region. This would place our region in the warm sector, with rain being the favored precipitation type on Wednesday. However as with any departing arctic air mass, there may be enough cold air to produce some freezing rain if precipitation can move in Tuesday night. Temperatures will then moderate further Wednesday. The most uncertainty then lies Wednesday night and Thursday as most model/ensemble guidance depicts secondary wave of low pressure riding along the frontal boundary near the region, although details to be determined. A secondary re-inforcing cold front will then move towards the area Friday with upslope snow showers possible. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... Conditions deteriorating tonight as storm system moves in. Most precip should be rain, though some freezing rain is possible at MRB and some sleet or snow could mix in elsewhere, briefly, but it should not accumulate at the other TAF sites. Low level wind shear will be a significant issue overnight along with rain, low clouds and low visibility. Rain ends very early Sunday with gusty winds, perhaps 40-45 knots, being the main issue most of the day. Highest winds in the afternoon. Winds lighten up slowly after that but otherwise remaining VFR Sunday night through Monday night. VFR expected for Tuesday with strong high pressure overhead. Potential for sub-VFR conditions then increases Wednesday into Thursday with widespread precipitation as next low pressure system moves into the area. Gusty southwest flow and low level wind shear may also become a concern Wednesday. && .MARINE... SCA remains in effect for the waters as low pressure crosses the region. Should then get very windy on Sunday as strong low pressure pulls away, so have gales for all waters. May need to extend gales into the night Sunday night and possibly Monday, then winds relax Monday night as high pressure moves overhead. Sub-SCA conditions expected Tuesday with high pressure overhead. SCA conditions then return Tuesday night through Thursday with increasing southwesterly flow ahead of the next low pressure system, turning northwest behind. && .TIDES/COASTAL FLOODING... Tides are elevated with onshore flow. Near minor flooding is possible through Sunday before strong northwest winds ensue. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Wind Advisory from 11 AM to 7 PM EST Sunday for DCZ001. MD...Wind Advisory from 7 AM to 7 PM EST Sunday for MDZ003-501-502. Winter Weather Advisory until 6 AM EST Sunday for MDZ003>006- 502. Wind Advisory from 11 AM to 7 PM EST Sunday for MDZ004>006-011- 013-014-016>018-503>508. Winter Weather Advisory until midnight EST tonight for MDZ507. Winter Storm Warning until 6 AM EST Sunday for MDZ501. VA...Wind Advisory from 7 AM to 7 PM EST Sunday for VAZ025>031-503- 504-507-508. Winter Weather Advisory until 6 AM EST Sunday for VAZ028-031. Wind Advisory from 11 AM to 7 PM EST Sunday for VAZ040-051>054- 501-502-505-506. Winter Weather Advisory until midnight EST tonight for VAZ026- 027-029-030-507. WV...Wind Advisory from 7 AM to 7 PM EST Sunday for WVZ050>053-055- 501>506. Winter Weather Advisory until 6 AM EST Sunday for WVZ050>053- 055-501>506. MARINE...Small Craft Advisory until 6 AM EST Sunday for ANZ532>534-537- 540>543. Gale Warning from 6 AM to 6 PM EST Sunday for ANZ530>543. && $$ SYNOPSIS...RCM NEAR TERM...RCM SHORT TERM...RCM LONG TERM...MM AVIATION...MM/RCM MARINE...MM/RCM TIDES/COASTAL FLOODING...DHOF