Area Forecast Discussion
Issued by NWS Wakefield, VA

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805 FXUS61 KAKQ 172026 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 426 PM EDT Thu Aug 17 2017 .SYNOPSIS... A warm and humid air mass remains in place across the Mid- Atlantic states tonight and Friday as the flow continues out of the south. The next cold front will arrive late on Friday night and exit the region by Saturday afternoon. High pressure builds in for Sunday through early next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... A warm and humid airmass is in place across the region this afternoon. There is a weak convergence boundary across the south central portion of VA into central NC from a lingering boundary associated with low pressure near Bermuda. There is some convection along this convergence boundary, but most of it is in NC and will remain out of the region. The remainder of the area is under the sw flow that is developing ahead of a cold front that is making its way across the Ohio valley. The models show a swath of moisture streaming northward out of the NC mountains with some associated convection that may impact the region this evening into the overnight hours. The models, both the 12z GFS and NAM take the energy associated with this convection and gradually organize it into an area of showers over the Lower MD Eastern Shore by Friday morning. So have increased the pops in that area toward morning getting pops to low likely range. The remainder of the area will otherwise be mainly dry, warm and humid overnight with lows in the low to mid 70s. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... The next cold front approaches late in the day on Friday into Friday night and moves the region by Saturday afternoon. This will be the dominate feature for this period and should produce some shower activity with the front with the best chance for convection across northern portions of the cwa. Further to the south, the lift is not as strong or as organized for not expecting as much pcpn there. So on Friday, will see some morning showers exiting the Delmarva and then a general wane in precipitation. Expect to see some scattered convection due to the heating of the day, but as the front arrives, activity should increase. The front slowly pushes southeast overnight reaching the SE portion of the CWA by Saturday morning. This is a bit of a change from the 00z and 6z model runs which stalled the front. But all the 12z guidance pushes the front to the south of the area by 18z. So have sped up the clearance of the pops by late Saturday afternoon. A strong shortwave trough sweeps across the Mid-Atlantic States Saturday night, but it remains north of the area and with the low level moisture gone, not anticipating much except some mid level clouds. By Sunday, high pressure will be over the region with dry and seasonable weather in place. For temperatures, will continue to see near normal weather with highs in the upper 80s to around 90 each day and lows in the low to mid 70s each night except for Saturday night when the drier air will allow temps to drop into the upper 60s to low 70s. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Sfc high pressure builds north of the area with stacked high pressure residing off the Southeast Coast through Mon night. A thermal trough develops in the lee of the Appalachians for Tue/Tue night, and then a cold front is expected to track through the area on Wed...exiting the coast late Wed night. Conditions will become increasingly more humid with each passing day. Sfc features rather diffuse for Mon, however seabreeze boundaries with the presence of ample moisture will keep a slight chance for showers/storms in the forecast... primarily for the aftn/early evening. Thunderstorm activity expected to become widely scattered Tue as convection develops invof lee trough. The frontal passage Wed/Wed night will provide a better focus for more organized thunderstorms to occur. Highs Mon-Wed generally upper 80s to lower 90s; low-mid 80s beaches. Lows Sun-Tue nights generally 70-75F. Lows Wed night mid-upper 60s NW to 70-75F SE. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... Latest radar shows some shower activity along the I-95 corridor, mainly south of RIC, moving east. The latest guidance suggests that these showers will dissipate and dive southeast this afternoon. As such, will keep any mention out of the terminals, with the exception of RIC where I will include VCSH 18-20Z. Otherwise, a weak boundary will move mainly north of the area later tonight into Friday morning. This may allow for additional shower activity at RIC and SBY, but confidence is not high enough to include in the terminals. Main story will be IFR cigs and possible VSBY at RIC late tonight into early Friday morning. With the wind staying around 5 kt, am expecting more of a lower stratus event vs. a low VSBY event at RIC. Elsewhere, it should remain VFR or MVFR with low probability of IFR expected. Outlook: A cold front approaches the region Friday into Saturday bringing another chance for showers, thunderstorms, and sub-VFR conditions. High pressure builds back into the region Sunday. && .MARINE... A boundary remains stalled just south of the Mason-Dixon line into Delaware this aftn. High pressure and fog/clouds earlier this morning have hampered widespread thunderstorm development today. However, isolated storms may still be possible over srn waters late this aftn/early evening. Winds generally SE around 10kt will increase to around 15kt and become more sly this evening into Friday as a cold front approaches the region. Seas/waves average 2-3ft. The cold front moves over the waters late Fri night into Sat. South winds average of 15kt Bay and 15-20kt ocean with the frontal passage. Seas build to 3-4ft north of Cape Charles Light Fri aftn and may even touch 5ft for a few hours out near 20NM as the front crosses the waters. SCA conditions still not anticipated with the increase in winds/seas Fri except with thunderstorms associated with the front. If any headlines are necessary, they can be handled with short-fused MWS or SMW products. Winds become more SW-W with speeds aob 10kt early Sat morning into Sun morning as the front stalls near the Mid Atlantic Coast, and then become more onshore Sun aftn into Mon as the front sags well south of the area. Seas subsiding from 2-3ft Sat morning to 2ft by Sat aftn through Mon night. Winds become S on Tue as a thermal trough develops inland with seas building to 2-3ft. Winds then become more SW aob 15kt Tue night/Wed as the next cold front is expected to cross the region; seas build to 3-4ft. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...ESS NEAR TERM...ESS SHORT TERM...ESS LONG TERM...BMD AVIATION...AJB/MRD MARINE...BMD is the U.S. government's official web portal to all federal, state and local government web resources and services.