Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 200248 CCA AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1046 PM EDT Sun Aug 19 2018 .SYNOPSIS... A cold front will slowly drop across the area through Monday morning. The front will stall over North Carolina Monday into Monday night, before lifting back north as a warm front Tuesday. A cold front crosses the area Wednesday. && .NEAR TERM /UNTIL 8 AM MONDAY MORNING/... As of 1045 PM EDT Sunday... Scattered convection continues to develop across the region this evening, mainly south of Interstate 64. This is due to the the shortwave trough that is over Ohio. The air mass remains moist across southern VA and NE NC so the scattered convection should continue into the overnight hours, but expect the number of showers to continue to diminish. These showers could produce brief heavy rain. The remainder off the area, including the northern neck and the Delmarva Peninsula should remain dry overnight. The location of the sfc boundary is difficult to find as the wind shift seems to have moved through a line from LKU- RIC- ECG. However, there seems to be little change in the surface airmass as most areas still show dewpoints in the low to mid 70s. The convection seems to be a little more robust south of the boundary but that appears to be the only difference. So have modified pops to be higher south of the boundary and diminish them moving north away from the boundary. Prev Discussion... An upper low is located over the lower Great Lakes this aftn, with WSW flow aloft over the Mid-Atlantic ahead of this feature. A subtle shortwave trough is tracking across the mountains and is triggering showers/tstms over the higher terrain and the Piedmont. Additionally, a narrow line of showers/tstms has developed in vicinity of the VA/NC border along what is likely a residual outflow or cold pool boundary from last nights convection. There is also some sea-breeze convection over the MD Ern Shore. The main cold front, though rather diffuse, appears to be located over nrn VA/NE MD/DE. Temperatures this aftn are primarily in the low/mid 80s with dewpoints around 70F N to the mid 70s S. The cold front will gradually push swd through the region this evening and overnight. This boundary combined with shortwave energy aloft should allow some convection to linger into the evening and early overnight hours, which has the potential to produce some localized heavy rain given rich moisture and some lift. PoPs will be highest (30-50%) along and S of the I-64 corridor, with 60% for NE NC, and aob 20% NE of I-64. Low temperatures tonight will generally be around 70F N to the low/mid 70s SE. Stratus is expected to develop along and N of the front later tonight into early Monday morning. && .SHORT TERM /8 AM MONDAY MORNING THROUGH WEDNESDAY/... As of 400 PM EDT Sunday... The cold front is expected to stall over nrn NC Monday. PoPs will for showers/tstms will be highest over NE NC in closer proximity to the front (40-50%), with 30-40% for central/srn VA, and aob 20% for the Ern Shore. The surface wind will be NE or E for much of the region, which combined with cloud cover will limit the rise in temperature for much of the area. Forecast highs range from upper 70s for the Atlantic coast of the Ern Shore, around 80F for the far NW Piedmont, to the mid 80s S. The front will lift back nwd and across the region as a warm front Monday night and Tuesday. This will occur as stronger surface low pressure organizes in the upper Midwest, and moves NE across the Great Lakes by Tuesday evening. Chances for showers/tstms will increase again over the entire region late Monday night through Tuesday. Lows Monday night range from 70-75F, and highs Tuesday in the mid/upper 80s. A cold front approaches from the NW Tuesday night and tracks across the area Wednesday. The primary moisture plume will be pushed offshore and PoPs will be lower (20-30%) with the frontal passage Wednesday. Lows Tuesday night will be in the low/mid 70s followed by highs Wednesday in the mid/upper 80s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 400 PM EDT Sunday... Drier and much cooler weather settles in Thursday, with only slight chance PoPs remaining across NC through mid-morning. 1024 mb high moves east over the Mid-Atlantic Thu PM thru Mon. 850mb temps in the +9 to +11 degC range spell out quite the cool down, with surface temps staying in the low 80s Thu, low-mid 80s Fri, and warming into the mid-upper 80s through the weekend. The only portion of our area with marginal rain chances Fri-Sat will be in NE NC, where ridging will be slightly weaker. 12z GFS wants to break down high pressure quicker, allowing for a few showers over NC/SE VA on Sunday...consider that solution TBD. Otherwise, dew points will be lower late week into the weekend, helping to make sensible weather more pleasant. Outdoor plans should fare well for the most part late week through the weekend, and into the start of next week. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... As of 800 PM EDT Sunday... Unsettled conditions continue this evening with an upper trough over the region, and a weak frontal boundary draped across the region just south of Petersburg. Scattered showers and tstms continue to develop especially along the Virginia/North Carolina border producing very heavy rain, lots of lightning, and MVFR/IFR conditions. With the frontal boundary in place and lots of moisture, scattered showers and the chance of tstms will be possible through the night over the region, although not much affect to TAF sites is likely. Confidence of a direct impact on a given terminal is low at this time. Stratus potentially develops late tonight into early Monday morning N of the front, mainly at RIC/SBY, and potentially PHF. The front lingers in vicinity of the VA/NC border Monday, then lifts back through the area as a warm front Tuesday, with a stronger cold front moving across the area Wednesday. Therefore, unsettled conditions will continue with daily chcs of showers/tstms. High pressure builds into the area later in the week. && .MARINE... As of 230 PM EDT Sunday... Rather tranquil on the marine area again this afternoon, despite frontal boundary being in the area. Front will gradually move into NC overnight, then stall, before coming back northward as a warm front on Tuesday. Winds turn NE behind the front, with some uncertainty regarding how strong. Appears strongest winds, mainly in the 12-18 kt range, will be across the northern and central portions of the Bay, and the northern half of the coastal waters. However, winds/waves/seas should remain below SCA criteria. Winds drop off for a time Monday night/early Tuesday as warm front lifts northward, then increase significantly from the south Tuesday afternoon/night ahead of stronger cold front approaching the area from the west. If models remain consistent, SCA will likely be needed in the 00Z Tuesday to at least 12Z Tuesday time frame. Cold front moves through on Wednesday. Model cold advection suggest winds are underdone in the models, and would anticipate a period of SCA winds on the Bay in the Wednesday night/Thursday time frame. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...AJZ/TMG NEAR TERM...AJZ/ESS SHORT TERM...AJZ/TMG LONG TERM...BMS AVIATION...AJZ/JEF MARINE...WRS

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