083 FXUS61 KLWX 281407 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1007 AM EDT Sun Apr 28 2024 .SYNOPSIS... Very warm temperatures for late April are expected today through Tuesday as high pressure sits off the Mid-Atlantic coast. Shower and thunderstorms chances return Tuesday afternoon and again Wednesday as a cold front crosses the region. High pressure briefly returns Thursday before another front arrives late week and into the weekend with additional afternoon showers and thunderstorms. && .NEAR TERM /THROUGH TONIGHT/... Dense Fog Advisories have been allowed to expire as visibilities continue to improve this morning and into midday. The weak upper level disturbance from earlier this morning continues to push east while strong upper level ridging/high pressure over the coastal Carolinas takes hold across the area today. With building heights and an ample supply of south to southwesterly flow, temperatures should rise fairly quickly heading into the afternoon hours. Highs today will push into the low to mid 80s in many locations with 70s over the mountains. Conditions will remain dry with sunny to mostly sunny skies even in areas that are seeing low clouds and fog this morning. A stray shower cannot be ruled out over the Potomac/Allegheny Highlands, but will be fairly short lived given limited shear aloft and overall forcing as the ridge builds overhead. Skies will remain mostly clear to partly cloudy tonight with areas of patchy dense fog in particular over the river valleys along and west of the Blue Ridge. Expect a mild night with lows in the upper 50s and low to mid 60s areawide. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... The mid-level high over the Carolinas moves northeast to start the week, bringing us dry conditions and the hottest temps of the week. Afternoon highs reach the mid to upper 80s, with low 90s possible along parts of the I-95 corridor into Central VA. Very mild Monday night as lows only drop to the low to mid 60s. The ridge aloft moves east of the area Tuesday as an upper trough and associated cold front cross the area. Well above normal warmth likely once again, with highs reaching the mid to upper 80s. Scattered showers and thunderstorms are forecast to develop along the cold front Tuesday afternoon through late evening. A few storms could be strong, through the chance for more active/severe storms looks to be low given dew points in the upper 50s to low 60s and weak deep-layer shear at 30kt or less. Still, storms that do develop are going to be capable of producing frequent lightning strikes and strong gusty winds. Shower/storm activity moves east of the area late in the evening, with some lingering showers through part of the overnight. Not much temp relief as overnight lows settle in the upper 50s to 60s once again. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Some scattered shower and thunderstorm activity could continue into Wednesday afternoon as a weak cold front moves through. Instability and shear remain limited, but a few storms could be strong. With the passage of the front, high temperatures could drop a few degrees into the upper 70s and low 80s, but the heat likely continues for the end of the week. Brief high pressure over the Northeast should suppress convection on Thursday, but a few showers could develop west of the Blue Ridge. An area of pressure is currently progged to move from the Midwest into Great Lakes Friday/Saturday. The associated cold front looks to be the main driver for the area's next chance for widespread showers over the weekend as it approaches from the west. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... Pockets of IFR and LIFR continue to reside at KIAD, KRMB, KJYO, KOKV, KHGR, and KHEF this morning due in part to low clouds and dense fog. The fog and low clouds have since eroded elsewhere across the corridor and at terminals back toward the west where VFR conditions prevail. Low cigs have also been noted at BWI, DCA, and MTN, but even here quick improvement has been noted. Expect full improvement across the terminals between 15-16z/11am-12pm. VFR and dry conditions expected this afternoon through Monday night, with southwest to west winds at 5-10 knots. A cold front sweeps through the area Tuesday afternoon and evening, bringing scattered showers and thunderstorms. The strongest storms will be capable of producing wind gusts over 35 knots and lightning strikes, as well as brief periods of reduced visibility. Convection moves east of the area late Tuesday evening. Mostly VFR conditions are expected Wednesday and Thursday, isolated to scattered showers/thunderstorms could bring sub-VFR conditions to the terminals. Northwest winds on Wednesday become southeasterly Thursday as a front returns north. && .MARINE... Southwest to south winds continue to diminish this morning, though a few lingering gusts to 15-18 knots are possible through mid morning in the central Chesapeake Bay and Tangier Sound. After that, favorable marine conditions are expected through Monday night as high pressure brings dry and much warmer conditions. A cold front is forecast to cross the local waters Tuesday afternoon and evening, bringing scattered showers and thunderstorms. These storms will be capable of producing wind gusts of 35 knots or greater and lightning strikes. Special Marine Warnings may be needed as these storms cross the waters. Showers/storms push east of the area late Tuesday night as winds turn northwest behind the front. Northwest winds on Wednesday become southeasterly Thursday as a front returns north. Isolated to scattered showers and thunderstorms could bring stronger gusts to the waters, especially on Wednesday. && .TIDES/COASTAL FLOODING... Tidal anomalies continue to be on the decrease at this time, so no further tidal flooding is expected over the next several high tide cycles for most areas. A few locations could perhaps be close to Minor during the Sunday morning high tide, but have been trending down. Tidal anomalies could increase slightly with persistent southwest flow early this week but no flooding is expected at this time. && .CLIMATE... Near-record to record warmth is possible on Monday afternoon. Below is a list of record high temperatures for April 29th, and the year the record was set. Apr 29th Climate Site Record High Forecast High Washington-National (DCA) 91F (2017+) 91F Washington-Dulles (IAD) 89F (2017) 89F Baltimore (BWI) 91F (1951) 89F Martinsburg (MRB) 93F (1974) 86F Charlottesville (CHO)* 92F (1974) 89F Hagerstown (HGR)* 90F (1974) 86F Annapolis (NAK)* 92F (1974) 83F + denotes that multiple years reached this value, but the depicted year is the most recent * denotes sites where Record Event Reports (RERs) are not issued && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...EST NEAR TERM...EST SHORT TERM...KRR LONG TERM...CAS AVIATION...CAS/KRR MARINE...CAS/KRR TIDES/COASTAL FLOODING...KRR CLIMATE...KRR