157 FXUS61 KLWX 141814 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 214 PM EDT Mon Sep 14 2020 .SYNOPSIS... High pressure moving into the Great Lakes out of Canada will build across New England through Tuesday. As the high pressure center shifts offshore Wednesday into Thursday, a cold front will follow in its wake. Meanwhile, Hurricane Sally will approach the north-central Gulf of Mexico Coast. The front is expected to dive south of the area by Friday morning, with another strong area of high pressure building out of Canada behind it likely suppressing the remnants of Sally to the south. This area of high pressure will gradually build across the Great Lakes and Northeast through the weekend. For the latest information on the track and strength of Sally (as well as several other tropical cyclones), please visit hurricanes.gov. && .NEAR TERM /THROUGH TONIGHT/... There is a hazy appearance to the sky this afternoon. This is a result of smoke lofted from wildfires out west being caught in the jet stream and moving overhead at about 20,000 to 25,000 ft. Northerly to northwesterly breezes are ushering in a drier and cooler airmass. At least some light wind will likely persist across the region through much of the night as a secondary (dry) cold front drops through, with slightly stronger winds (15-20 mph gusts at times) near/east of I-95. This probably won't allow much radiational cooling except perhaps in the most sheltered valley locations, but if winds do go calm, dew points dropping well into the 40s could allow temperatures to do likewise. Otherwise, temps likely hold in the 50s. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... High pressure will pivot across New England Tuesday into Tuesday night before moving offshore Wednesday. Dry conditions are expected during this time, though a light onshore flow will lead to an uptick in humidity. This may result in a few extra clouds or patchy fog especially during the overnight hours. Otherwise, highs will generally be in the 70s with lows in the 50s and 60s. It is likely that smoke from wildfires out west continues to obscure what would otherwise be a vibrantly clear sky the next couple days. Clouds will increase Wednesday night ahead of an approaching cold front and well in advance of the remnants of Sally near the Gulf of Mexico Coast. A shower or two may make it into west- central Virginia by daybreak Thursday, but chances are pretty low. && .LONG TERM /THURSDAY THROUGH MONDAY/... A strong upper-level low draped near Montreal will allow for a weak/moderate cold frontal passage through our area Thursday into early Friday. This, along with the remnants of Sally will keep the Mid-Atlantic/SE moist leading into the weekend. Guidance wants to keep the remnant low pressure from Sally south of our CWA leading to minimal impacts (if any) for the area. Depending on future track shifts, impacts may increase as we get closer to the event. We will continue to hold on to chances for precip (Thu-Fri) associated with the cold front passing through but overall impacts look to be lack-luster with PWATs well below 2" and overall QPF totals remaining below an inch. Aside from any meandering these two systems decide to do, expect just a chance for scattered showers leading into the weekend. Continue to follow the National Hurricane Center for official updates on the track and strength of Sally. Heading into the weekend, Canadian high pressure will begin to reside across the area leading to fairly swift zonal flow through Sunday into early next week. Chances for any precip appear to be near zero. Temperatures for the extended are shaping up to be a bit cooler than normal with highs struggling to reach 70F by Sunday. Northerly winds will allow us to keep a cooler air mass over us as the weekend progresses. We may begin to see our first look at frost for some locations during the weekend with lows potentially dipping down into the 40s in some areas, with 30s not out of the question in sheltered high elevation valleys near the Appalachian Mountains. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR expected thru Wed night, with a small chc of patchy fog or a few low clouds early Wed AM. N flow w/ gusts to 20 kt abate this eve then turn S Tue-Wed. Sub-VFR conditions are possible Thu-early Fri as scattered showers associated w/ a passing cold front affect the area. && .MARINE... Northerly winds gusting 20 to 30 knots are expected at times through tonight behind a cold front. Winds will become lighter Tuesday then turn to the south through Wednesday. Dry weather is expected during this time. SCA criteria may be reached late Thursday into Friday with a northerly wind shift associated with a passing cold front. && .TIDES/COASTAL FLOODING... Northerly flow is helping reduce water levels this afternoon, and will continue to do so through Tuesday morning. Given the trajectory of the flow (especially tonight when it becomes east of north), water is being held into/bottled up at the mouth of the Chesapeake Bay. Anomalies of 1-1.25 feet are currently being observed near Norfolk, and this excess water will return northward by Wednesday as lighter winds turn back around to the south. This will likely result in minor tidal flooding during the middle portion of the week. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until noon EDT Tuesday for ANZ530>534-537- 539>541-543. Small Craft Advisory until 6 AM EDT Tuesday for ANZ535-536-538- 542. && $$ SYNOPSIS...DHOF NEAR TERM...DHOF SHORT TERM...DHOF LONG TERM...ADM AVIATION...DHOF/ADM MARINE...DHOF/ADM TIDES/COASTAL FLOODING...DHOF