Marine Weather and Tide Forecast for Tall Timbers, MD

KEY MESSAGES
1) Numerous showers/storms are forecast this afternoon and early evening. Strong to severe storms have the ability to produce damaging winds, large hail, and a brief tornado.
Localized flash flooding in urban/flood prone areas is also a threat. A Flood Watch and a Severe Thunderstorm Watch are in effect through late evening for a large majority of the area.

2) A more summer-like pattern takes hold Wednesday night into the weekend.

DISCUSSION
As of 235 PM EDT Tuesday...

KEY MESSAGE 1...Numerous showers/storms are forecast this afternoon and early evening. Strong to severe storms have the ability to produce damaging winds, large hail, and a brief tornado.
Localized flash flooding in urban/flood prone areas is also a threat. A Flood Watch and a Severe Thunderstorm Watch are in effect through late evening for a large majority of the area.

A slow moving cold front will cross the area late this evening with a surface low forming and deepening along the front with an associated upper shortwave/MCV. Before the clouds covered the area, ample amounts of sun allowed temperatures and moisture levels to rebound in the area, particularly SE VA/NE NC, this morning. This has allowed for more than enough MLCAPE across the area with analyzed values over 1500 J/kg across the eastern half of the area.
Additionally, there is more shear with the front/MCV than previous days with 30-40 kt of effective bulk shear across the area. Strong to severe storms have already developed across the area, with likely more to come. Convection will continue through the afternoon and evening, moving offshore by ~8 PM. There is a threat for damaging wind gusts given sufficient sfc heating and enhanced mid/upper flow which will allow for some degree of storm organization, especially near the coast. In addition, there is a low but nonzero tornado threat near the center of the low (especially near the coast) where the LLVL flow could be locally backed. A Severe Thunderstorm Watch has been issued for a large portion of the area, excluding the NW piedmont counties, through 8 PM.

In addition to the severe threat, there is a threat for locally heavy rainfall, with the greatest concern east of I-95 and a little bit to the north of the low track where some training of storms appears likely. With PWATs above ~2.0", rainfall rates will be efficient. The latest CAMs agree on a localized area receiving up to 3-5" of rain with a more general 1-2" across the area. The Flood Watch was expanded this morning to include central and coastal VA, as rainfall amounts could exceed 1-2" of rain with localized 3-4" in the areas. Comfortable tonight with lows in the upper 50s-60s.

KEY MESSAGE 2...A more summer-like pattern takes hold Wednesday night into the weekend.

A drier airmass will take over behind the cold front, keeping Wednesday dry. Temperatures won't be much cooler though, with highs near normal in the mid to upper 80s across the area Wednesday. By Wednesday night, winds will quickly shift back to the SE-S and bring back normal June humidity amd temperatures. For the remainder of the week, a more typical summertime pattern sets up. Upper heights gradually rise on Thu/Fri, with dry wx continuing on Thu and isolated aftn/evening storms possible Fri (mainly N/NW). There is a better chc of tstms Saturday aftn/evening as a more well defined shortwave crosses the area. Expect highs mainly in the upper 80s and low 90s, with overnight lows in the 60s to near 70F.

AVIATION /19Z TUESDAY THROUGH SUNDAY/
As of 145 PM EDT Tuesday...

Degraded flight conditions from widespread rain and storms have pushed into the area this afternoon from the west, currently affect RIC with MVFR CIGs and IFR VSBYs. Storms in the area have the potential of becoming severe and produce gusty winds of 30-40kt+. The showers/storms will continue to move eastward throughout the afternoon and evening, likely reaching the SE VA terminals (ORF/PHF) around 20-22z. Low IFR/MVFR clouds will linger after the convection into late evening. Conditions will then improve to VFR after midnight as drier air moves in from the NW.

Outlook: Mainly dry/VFR Wednesday. Late day showers/storms possible Thursday and Friday.

MARINE
As of 225 PM EDT Tuesday...

Key Messages:

- A cold front will move across the local waters this afternoon. Decent cold air advection forecast for behind the front has prompted the issuance of SCAs for the Bay and lower James this evening through early Wednesday morning.

- Benign, sub-SCA conditions are expected for much of the rest of the week.

A cold front with low pressure developing along it was progressing through Central VA as of early afternoon sfc analysis. Showers and thunderstorms have already started moving in over the upper tidal rivers and will continue east through the rest of the afternoon.
Some storms may be strong or severe with wind gusts in excess of 60mph and waterspouts possible. There is also a low-end potential for hail.

In the wake of the front, a surge of CAA is expected to push across the waters. Local wind probs for sustained winds of 18 kts across the Bay have increased to 80-90%, so SCAs have been issued to capture this brief NW wind surge between 20z-08z for the Bay, and 00z-05z for the lower James. A few gusts to ~25 kt are possible across the coastal waters, but not issue a SCA for the coastal waters at this time, especially since we are not expecting rapidly building seas due to the less than favorable wind direction (NW).
After this brief wind surge, winds will quickly decrease across all waters as high pressure builds back over the region. Light winds prevail Wednesday and most of Thursday, then breezy south winds come back Thursday evening into Friday.

AKQ WATCHES/WARNINGS/ADVISORIES
MD...Flood Watch until 10 PM EDT this evening for MDZ022>024.
NC...None.
VA...Flood Watch until 10 PM EDT this evening for VAZ077-078- 084>086-088>090-092-097>100-523>525-528>531.
MARINE...Small Craft Advisory until 4 AM EDT Wednesday for ANZ630>632- 634.
Small Craft Advisory from 7 PM this evening to 1 AM EDT Wednesday for ANZ639.