Marine Weather and Tide Forecast for Williamsburg, VA

NEAR TERM /UNTIL 6 AM TUESDAY MORNING/
As of 849 PM EDT Monday...

Key Message:

- Mainly clear and not quite as cool tonight. Early morning lows mainly in the 40s to lower 50s.

A clear, cool evening is ongoing across the forecast area.
Temperatures have quickly dropped into the upper 50s to lower 60s.
High pressure has settled right along the Mid-Atlantic coast, and winds are light. Aloft, a ridge is building across the eastern U.S., and northwesterly flow still prevails across the region. A quiet night is on tap for the forecast area, with clear skies and light winds expected again tonight. While this is usually favorable for good radiational cooling, southeast to south flow will help pull in a more modified airmass. Dew points will increase into the upper 40s to near 50 degrees overnight, which will keep the lower limit of temperatures in the upper 40s. Most communities can expect temperatures to drop into the upper 40s to lower 50s.

SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/
As of 230 PM EDT Monday...

Key Messages:

- Warming temperatures and continued dry conditions are expected Tuesday.

- Very warm on Wednesday with mid to upper 80s expected.

- Scattered showers and thunderstorms are expected Wednesday afternoon and evening, with the best chances along and south of I-64. Organized severe weather is not expected, but a few stronger storms remain possible with gusty winds as the main threat.

The ridge aloft crests over the east coast Tuesday before sliding offshore through midweek. Meanwhile, the sfc ridge slides into position off the SE coast, allowing low-level flow to veer to the SSW and increase. Frequent gusts to 20-25 mph are likely Tuesday afternoon and evening. Strong WAA allows highs to climb into the lower to mid 80s (upper 70s on the eastern shore) tomorrow. CAMs still show some convection develops west of the mountains Tue aftn/evening, crossing the mountains and likely weakening (and eventually dissipate) as it approaches the area early Wed AM, as instability will be very limited east of the mountains thanks to the lower dewpts. However, any residual boundaries from dissipating tstms may contribute to convective initiation over the local area Wed aftn. While a cold front approaches from the N on Wed, it will slow and ultimately stall Wed aftn before reaching the local area. Even warmer on Wed with continued breezy SW flow. Widespread mid to upper 80s are expected with dewpts rising into the lower 60s by the aftn/evening. The higher Td values allow for moderate surface- based instability (1000-1500 J/kg of MLCAPE) to develop by the afternoon. This combined with mid/upper height falls due to the ridge becoming suppressed to our SE and any residual boundaries from Tuesday's convection should allow for scattered tstms to develop across the area. While it is hard to pinpoint specifics attm, first look at CAMs for Wednesday continue to highlight the highest tstm chances look to be along and south of I-64, with most likely timing for tstms from 3-10 PM Wed with diurnal weakening expected in the late evening and overnight given relatively weak/unidirectional shear. So while organized severe wx isn't expected owing to the weak shear, a few strong to marginally severe storms are possible, with damaging wind gusts likely being the main threat.

LONG TERM /THURSDAY THROUGH MONDAY/
As of 230 PM EDT Monday...

Key Messages:

- Highs will be well into the 80s on Thursday and Friday, with continued shower/storm chances.

- Cooler and dry weather returns over the weekend in the wake of a cold front.

Deepening sfc low pressure is progged to track from the Midwest to Quebec from Thursday-Friday night. 12z/28 model trends favor lifting the front back north as a warm front on Thu, keeping the better forcing off to the north, but additional isolated to widely scattered showers and storms will be possible Thu aftn into the evening. PoPs were capped at 30% Thu.

This feature eventually drags a seasonally strong cold front toward the area late Thu into Fri, with that cold front expected to cross the area Friday night/Saturday AM. The associated shortwave trough aloft approaches the local area on Friday, before it crosses the area late Friday into Saturday morning.
We'll maintain above normal temps through Friday, as high pressure remains anchored over the western Atlantic. High temperatures well into the 80s are expected inland on both days. Dewpts will be in the low to locally mid 60s, so it actually feel somewhat humid Thu/Fri. The slow-moving front then looks to bring multiple rounds of showers/tstms Friday evening into Saturday.

LREF/NBM ensembles showing potential for locally strong to severe storms with the frontal passage that will need to be monitored for Friday night. Deep layer shear of 30-35kt (0-6km), and a decent chance (30-50% probability) of MLCAPE of 750-1000 J/Kg also portends at least the potential for some gusty winds with the initial frontal passage Friday evening. Only issue to be ironed out is typical temporal resolution issues, which will be monitored with time.

Latest model trends show the front hanging up along the coast into the day on Saturday, potentially bringing some lingering showers and storms across the SE coast Sat afternoon. Otherwise, drier and cooler weather arrives behind the cold front for the weekend into early next week with highs falling back in the 70s, with lows back into the 40s and 50s.

AVIATION /01Z TUESDAY THROUGH SATURDAY/
As of 726 PM EDT Monday...

VFR conditions will prevail at all terminals through the TAF period.
Winds will remain light overnight and will be quickly veering from the southeast to the south/southwest. Wind speeds will start to increase late tomorrow morning, with gusts of between 15 to 20 kts (closer to 20 to 25 kts at RIC and SBY) expected by tomorrow afternoon.

Outlook: VFR conditions are expected to prevail through Wednesday morning. Breezy SW winds develop Tuesday, gusting to 20 kt by afternoon. A cold front approaches from the north by later Wednesday into Thursday bringing an increased chance of showers and storms. A stronger front crosses the region late Friday into Saturday, bringing a better chance for widespread showers and storms Friday afternoon into Saturday morning.

MARINE
As of 300 PM EDT Monday...

Key Messages:

- Small Craft Advisories have been issued for the James River, Chesapeake Bay, and northern coastal waters Tuesday evening through Wednesday morning.

- Quieter marine conditions Wednesday and Thursday, outside of scattered afternoon and evening thunderstorms.

- Small Craft Advisories again possible at the end of the week.

Winds across the local waters this afternoon are light and variable with high pressure centered just offshore of Virginia Beach. An easterly sea breeze has also developed along the immediate coast. As the high shifts further offshore tonight, the wind direction becomes S-SE and increases to 10-15 kt, especially in the Chesapeake Bay. A few gusts to around 20 kt are possible closer to sunrise Tuesday. A weakening cold front approaches from the N/NW later Tuesday and the pressure gradient tightens as a result. 80-100% probabilities reflect strong confidence in meeting Small Craft Advisory criteria and headlines have been issued for the James River, Chesapeake Bay, and coastal waters N of Cape Charles from Tuesday night through most of Wednesday morning for SSW winds 15-25 kt with gusts 25-30 kt (highest on the coastal waters).
Confidence in meeting SCA criteria is lower in the southern coastal waters and in the York and Rappahannock Rivers, but will allow the next shift to reevaluate the potential in these zones. The gradient again relaxes as the weakening front drops into the region later Wednesday, with light easterly or a variable wind direction expected. The front pushes back N as a warm front Thursday evening and the wind direction shifts back to the SW. Marginal SCAs are again possible Thursday night through Saturday as another stronger cold front approaches.
Afternoon/evening showers and storms may also cause locally higher winds and waves Wednesday, Thursday, Friday, and Saturday.

Waves in the bay build to 2-3 ft Tuesday night with seas building to 3-5 ft. Wave guidance shows some potential for 6 ft seas out 20 nm across the N, but confidence in this is low. Another period of elevated waves and seas arrives Friday afternoon into Saturday.

AKQ WATCHES/WARNINGS/ADVISORIES
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 7 PM Tuesday to 7 AM EDT Wednesday for ANZ630-631-650-652-654.
Small Craft Advisory from 7 PM Tuesday to 10 AM EDT Wednesday for ANZ632-634.
Small Craft Advisory from 10 PM Tuesday to 7 AM EDT Wednesday for ANZ637-638.