Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
884 FXUS61 KLWX 170054 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 854 PM EDT Wed Sep 16 2026 .WHAT HAS CHANGED... The lingering showers over the Potomac Highlands have now dissipated, though additional light showers possible late tonight. && .KEY MESSAGES... - 1) Turning warmer and more humid with a return of shower and thunderstorm chances for Thursday and Friday. - 2) Rain-free and less muggy conditions are likely on Saturday, before the weather turns more unsettled again from Sunday into next week. && .DISCUSSION... KEY MESSAGE 1...Turning warmer and more humid with a return of shower and thunderstorm chances for Thursday and Friday. The late afternoon to evening showers and a few rumbles of thunder in the Alleghenies and Potomac Highlands have now dissipated. Expecting mostly dry conditions for the first half of the night, then scattered showers approach the mountains late. Cloud cover is expected to increase after midnight from the north and west. For Thursday, the prospects for showers and thunderstorms will increase by mid to late afternoon, especially for the Alleghenies, the Shenandoah Valley, and the I-95 corridor. This is tied to a slow moving cold front, making a gradual approach from the Ohio Valley and Pennsylvania. As you head farther southeast through Virginia and into the coastal plain, the chances for rain should decrease. Thursday looks like the warmest day of the week, although this is contingent on how much sunshine/heating can take place earlier in the day. At this juncture, we`re expecting highs well into the 80s again, with parts of the Shenandoah Valley up towards the I-95 corridor perhaps making a run at 90. By Friday, the frontal boundary itself should be across central to southern VA. This will lead to a continued chance of showers, along with somewhat cooler readings as compared to Thursday. KEY MESSAGE 2...Rain-free and less muggy conditions are likely on Saturday, before the weather turns more unsettled again from Sunday into next week. Current indications point to a rain-free start to the weekend, with the above mentioned cold front pushing down into the Carolinas, and weak high pressure building down from the north. However, signals also point to more unsettled weather from Sunday into next week, as a persistent upper ridge axis gets shunted towards the deep South, allowing upper-level impulses to move across the Mid-Atlantic from the west. This should provide the impetus for at least hit and miss showers and thunderstorms on a daily basis. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Predominantly VFR conds are expected areawide through Thursday morning. Periods of passing showers and thunderstorms are possible at times Thursday afternoon and again Thursday evening, with PROB30 groups added to most TAF sites. Could see CIGs approach MVFR thresholds, but confidence is low at this time. A cold front moves through the region early Friday which yields a shift to northerly winds. Afternoon gusts could approach 15 to 20 knots, with any storm chances back toward central Virginia. High pressure passing to our north shifts winds out of the east to southeast Saturday, turning southwesterly by Sunday. Over the weekend, gusts up to 15 to perhaps 20 knots are possible. In general, expect predominantly VFR conditions to persist, but flight conditions could deteriorate as shower and thunderstorm potential increase late in the weekend. && .MARINE... Canadian high pressure remains nearby into tonight, favoring sub-SCA conditions over the waters. By Thursday, this ridge edges offshore ahead of the next cold front. Ahead of this system, southerly winds increase which could near Small Craft Advisory levels on Thursday afternoon/evening. This is particularly the case over wider waters of the Chesapeake Bay due to southerly channeling. The cold front crosses the waters early Friday which shifts winds over to northerly. Breezy conditions in the wake could again near advisory levels. As high pressure tracks across southern Quebec, marine winds turn northeasterly into Friday night with gusts around 10 to 15 knots. High pressure passing to our north shifts winds out of the east to southeast Saturday, turning southwesterly on Sunday. Over the weekend, gusts up to 15 to perhaps 20 knots are possible. && .TIDES/COASTAL FLOODING... As winds have turned more south to southeasterly, the onshore flow has raised tidal anomalies to just below 1 foot. This has been enough to push a few of the more sensitive locations into the Action stage. Until the cold front moves through early Friday, water levels will remain somewhat elevated. Although no tidal site is shown to experience any coastal flooding, it will need to be monitored. This is particularly the case at Annapolis, especially during the higher of the two astronomical high tides. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ DISCUSSION...BRO/KVH/KRR AVIATION...BRO/KVH/KRR MARINE...BRO/KVH/KRR