Marine Weather and Tide Forecast for Oakton, VA

KEY MESSAGES
- 1) Intermittent showers & thunderstorms possible between Thursday evening and Saturday as a slow moving cold front tracks through the region.

- 2) Above normal temperatures and dry conditions expected Monday and Tuesday; showers possible along a cold front by the middle of next week.

DISCUSSION
KEY MESSAGE 1...Intermittent showers & thunderstorms possible between Thursday evening and Saturday as a slow moving cold front tracks through the region.
So far any shower and thunderstorm activity has been pretty meager east of the mountains early this afternoon given a subtle stable layer aloft. It's a mashup of SCT-OVC cloud cover as a result of a cold front dropping south from Lake Erie and multiple pieces of shortwave energy ejecting east northeast from central WV and the south-central Ohio River Valley. Expect this activity to gradually drift east and northeast this evening as the shortwave shunts eastward and cold front drops south. The bulk of any shower activity should hold off until near midnight and continue through the pre- dawn hours of Friday morning. Shower activity will be relatively light to moderate with even a few embedded thunderstorms mixed in.

The severe weather threat appears low, but not zero given CAPE values hovering between 500-1500 j/kg and shear values around 30-40 kts. With a stronger piece of shortwave energy set to kick east out of WV expect an uptick in thunderstorm chances mainly across central VA and southern MD this evening where instability will be maximized due to more sunshine. These areas could see spotty clusters of thunderstorms with gusty winds as the primary threat along with frequent lightning and locally heavy rainfall. Not everyone will see the rain this afternoon and evening with more scattered to widespread showers expected later this evening and pre-dawn Friday morning as the front drops through.

Highs today will range from the mid 80s along the PA/MD line to low 90s over southern MD and central VA (70S mountains). Lows tonight will fall back into the low to mid 60s with upper 60s over central VA and southern MD. Some fog is possible west of the Blue Ridge although low clouds may be a bit more prevalent given the front nearby.

Additional rain showers could track east through the region Friday morning as the front sags to the south. Behind the front, instability lingers as a shortwave trough builds over the Ohio River Valley and begins to move through the region. This could bring additional intermittent showers and thunderstorms through the region late Friday and into Saturday as this system moves through. All told, total rainfall accumulation over the next 48-72 hours could range between 0.5 inches to greater than 1 inch in areas that receive multiple rounds of these intermittent showers/storms.

Highs through the weekend range in the mid-80s across most of the area, with humidity remaining elevated as the cold front slowly meanders to the south.

KEY MESSAGE 2...Above normal temperatures and dry conditions expected Monday and Tuesday; showers possible along a cold front by the middle of next week.

An upper level ridge is expected build overhead during the first half of next week supporting warmer than normal temperatures and dry conditions. The ridge starts breaking down during the second half of the week as a shortwave-trough digs across the Great Lakes. A cold front is forecast to cross the area next Thursday and will likely bring a few showers or possible thunderstorms, but the probability of severe wx remains too low.



AVIATION /19Z THURSDAY THROUGH TUESDAY/
VFR conditions are expected amongst the terminals through this evening. Temporary reductions are possible at times (21-02z/5-9pm)
this evening due to spotty showers and thunderstorms. Highest confidence for afternoon showers and storms appears to be from a line south of CBE/MRB/IAD/DCA to BWI/MTN.

The coverage of showers and embedded thunderstorms likely increases later this evening and overnight as the a ripple of energy ejects east from the Ohio River Valley and cold front drops south from PA.
Expect showers to move in from the west between 3-6z/10pm-2am before becoming more scattered to widespread across all terminals from 7z- 15/3am-11am Friday. Went will prevailing showers instead of Prob30s based on consistency amongst the hi-res guidance along with radar trends. Cigs will continue to bounce around with SCT-OVC mid and high level cloud decks expected well into the overnight hours.

Beyond the showers and thunderstorms, not looking at a whole lot of low clouds nor fog outside the mountains. MAV/MET guidance continues to hold a high likelihood of low cigs/vsbys mainly west of Blue Ridge heading into Friday morning. This will be something to monitor in subsequent TAF cycles. FOr now opted in for low clouds and even a little fog at both MRB/CHO although confidence is low. Any temporary restrictions this evening into early Friday morning will give way to VFR conditions Friday afternoon as brief dry air moves into the region. A leftover shower or thunderstorm is possible from KCHO south Friday afternoon and evening as the front stalls nearby.

Additional scattered showers and thunderstorms are possible during the afternoon/evening hours this weekend. This will lead to temporary reductions amongst the terminals at times otherwise VFR conditions will prevail. South to southeast winds Saturday will switch to the west and southwest winds Sunday at less than 15 kts.
Fair weather conditions expected during the first half of next week.
Winds turn to the north and northwest Monday and Tuesday as VFR conditions continue.



MARINE
Showers and a few thunderstorms are anticipated later this evening into tonight. A few Special Marine Warnings are possible, especially toward southern MD. Winds shift to the west and northwest tonight as a cold front crosses, then shift to north and east through Friday as the front stalls to the south. Winds shift to south and southeast on Saturday with southerly channeling yielding Small Craft Advisory criteria winds in the afternoon.

West winds on Sunday shift to northerly on Monday, remaining below SCA criteria each day. Showers and an isolated thunderstorm are possible over the waters on both Saturday and Sunday, although SMWs are not likely.

SCA conditions expected Monday into Tuesday on northerly winds.

TIDES/COASTAL FLOODING
Tide levels remain normal over the next couple of days as prevailing winds remain light. Looking towards late Saturday, levels increase again ahead of a warm front moving through the region on Sunday.



LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.