Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
001 FXUS61 KLWX 191500 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1100 AM EDT Fri Jul 19 2024 .SYNOPSIS... A front over the Carolinas will drift northward and weaken this weekend as high pressure slides by to the north. Bermuda high pressure offshore will linger through next week as another front meanders to the north. && .NEAR TERM /THROUGH TONIGHT/... Northeast to southeast flow and a mix of cumulus and cirrus are resulting in slightly below normal temperatures and lower humidity across the Mid-Atlantic. A front remains stalled over the Carolinas while high pressure builds from the Ohio River Valley toward New England. Any shower activity looks to be very brief, isolated, and limited to near the higher terrain given weak forcing and dry air. Clouds (especially cirrus) look to linger tonight as a jet streak pivots across and weak low pressure develops to the south. Humidity ticks up slightly with low temperatures near to slightly below normal for mid July. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... On Saturday, the stalled boundary to our south is expected to meander northward as a shortwave passes overhead. Precip chances will increase from southwest to northeast through the day, bringing much needed rainfall to the area. Cloud cover will keep high temperatures below normal, topping out in the low to 80s for most of the area. Rain chances drop off overnight as the shortwave exits and forcing is lost. Low temperatures will be a few degrees cooler than Friday, in the low to mid 60s for most. The front likely remains stalled to our south into Sunday, limiting PoPs to our southern zones. Expect coverage to be reduced compared to Saturday with subsidence on the back end of the exiting shortwave. Reduced cloud cover and southerly flow brings highs back to the upper 80s and low 90s. Clouds build in overnight resulting in milder lows, hovering in the 70s along and east of the I-95 corridor and mid-upper 60s expected elsewhere. && .LONG TERM /MONDAY THROUGH THURSDAY/... Showers and thunderstorms look to cement their place in the forecast each day next week as several waves of low pressure aloft pass over the region. The axis of the Bermuda Ridge builds into the far southwest Atlantic to start the week, and eventually over FL/GA and the Carolinas by mid week. This puts our area in a steady fetch of south to southwesterly flow that continually advects deep moisture from the Gulf of Mexico. An upper trough approaches from the west late in the week, though the exact timing and strength of this system varies. Rainfall is likely to be mostly beneficial, especially west of US-15 where extreme drought conditions are being observed. Locally heavy rainfall in the I-95 urban corridor could result in some flooding issues if storms persist over an area. Abundant cloud cover keeps highs near normal for late July, in the mid to upper 80s, with spotty low 90s. Overnight lows will be in the mid 60s to low 70s. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... VFR conditions are forecast to prevail through the weekend, though some patches of MVFR CIGs are possible near CHO during the early morning hours as they are closer to a front meandering to the south. Weak low pressure along this front may deliver occasional shower activity to the terminals along with brief restrictions Saturday. Generally weak instability lowers confidence in thunder potential. Winds will become SE to S through Saturday, then NW Saturday night-Sunday at 5-10 kts. Daily showers and thunderstorms return to the forecast for next week. The highest rain chances will be in the afternoon to early evening each day, with storms that move over a terminal likely to produce brief sub-VFR conditions. Outside of showers/storms, VFR conditions are expected in southerly winds around 5-10 knots. && .MARINE... SE to S winds are forecast through Saturday. Showers and a few thunderstorms are possible Saturday as weak low pressure moves along a front moving up from the south. Winds become NW Sunday, and look to remain below SCA levels through the weekend. Southerly winds remain below SCA criteria Monday and for most of Tuesday. Daily showers and thunderstorms are expected next week, with some storms possibly producing wind gusts in excess of 35 knots and frequent lightning strikes. Stronger southerly channeling Tuesday night could produce SCA conditions in the open waters of the central Chesapeake Bay. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...DHOF/EST NEAR TERM...DHOF/CAS SHORT TERM...DHOF/CAS LONG TERM...KRR AVIATION...DHOF/CAS/KRR MARINE...DHOF/CAS/KRR