Marine Weather and Tide Forecast for Colonial Heights, VA

NEAR TERM /THROUGH TONIGHT/
As of 300 AM EDT Wednesday...

Key Messages:

- Continued warm today with mid to upper 80s expected.

- Scattered showers and thunderstorms are develop this afternoon and evening, with the best chances along and south of I-64. A few of the storms could produce locally damaging wind gusts, especially across south/southeast VA.

Early morning wx analysis shows ridging aloft centered along the SE CONUS coast, with sfc high pressure off the Carolina coast. As expected, convection to our west is rapidly weakening as it approaches (although a few very brief downpours are possible across the northern neck/eastern shore during the next few hours). It is quite mild with temps in the mid 60s-70F at this hour with a SW wind of 10-15 mph. A backdoor cold front just to our north will cross part of the area (mainly the eastern shore) today. Very warm wx is expected across much of the area with widespread mid to upper 80s in most of our VA/NC zones (w/ upper 70s-lower 80s on the eastern shore). However, the main forecast challenge will be timing/placement of afternoon/evening tstms. The aforementioned backdoor front and leftover boundaries from this morning's weakening convection will likely serve as a focal points for convective initiation this afternoon. Models have come into better agreement regarding placement and timing of convection. The first storms of the day likely form near or just south of a Farmville-Richmond- Williamsburg line around 2-4 PM before increasing in coverage during the late aftn/early evening as they progress southward before gradually weakening after 9-10 PM as they push into NE NC. The most likely timing for storms is 2-6 PM across central VA (including RIC), 5-10 PM in SE VA, and 7-11 PM in NE NC. With temps in the mid- upper 80s and lower-mid 60s dew pts south of the front, moderate instability (MLCAPE of 1000-1500 J/kg) will be present. While deep layer shear and mid-level lapse rates will be weak, a few of the storms could produce 45 to 60 mph wind gusts given the strong sfc heating and resultant downburst/cold pool potential. Gusts in this range could result in localized tree/power line damage. Mainly dry wx is expected after midnight tonight with lows in the lower 60s in most areas (mid 50s on the eastern shore with weak onshore flow).

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
As of 300 AM EDT Wednesday...

Key Message:

- A few showers and storms are possible across mainly N/NW portions of the area Thursday and Friday afternoon/evening with continued warm weather, as the approaching cold front will likely remain well to our NW through the end of the workweek.

The ridge aloft to expand back to the N a bit on Thu before becoming more suppressed on Friday. Meanwhile, the backdoor front quickly retreats northward on Thu as low pressure begins to deepen as it tracks from the Plains to southern Great Lakes. With the retreating front and strong low still well to our NW, and rising upper heights, the best forcing for ascent will be off to the north/northwest.
However, isolated showers and storms will be possible Thu aftn into the evening, mainly across N/NW portions of the FA. Severe wx is not expected on Thu, and doubt that we'll see much in the way of convection with the rising upper heights and not much forcing for ascent. Very warm inland w/ highs well into the 80s on Thu. The temperature forecast is tricky near the coast with the flow remaining onshore for most of the day. There may very well be a decent temperature gradient between places like Ocean City (where temps struggle to get out of the 60s) and the western part of the MD Eastern Shore (with temps near 80F).

The above mentioned low pressure system will continue to deepen as it tracks NE through the end of the week, reaching Quebec by Friday night. This feature eventually drags a seasonally strong cold front toward the area late Friday. The associated shortwave trough aloft remains well to our W through Fri night, only reaching IL/IN. The 00z/30 models have continued to be slower with the front, with most of the convection expected to be near/just west of the mountains on Fri/Fri night with isolated to perhaps scattered tstms across our area. Remaining very warm Friday, with highs well into the 80s (perhaps upper 80s for the SE 1/2 of the CWA).

LONG TERM /SATURDAY THROUGH TUESDAY/
As of 300 AM EDT Wednesday...

Key Messages:

- Shower/storms are likely on Saturday as a cold front crosses the area.

- The forecast for late next weekend into early next week remains highly uncertain given varying model solutions with respect to a slow moving upper trough that could potentially become cut off.

The shortwave trough aloft approaches the local area this weekend, There are still significant model and ensemble differences with respect to the evolution of that shortwave, although the 00z/30 models and ensembles continue to trend toward a cutoff low forming to our west by late in the weekend.
The GFS/GEFS remain very progressive and forecast the shortwave to move offshore by late in the weekend. However, am beginning to lean toward the cutoff low solution given ensemble trends from the CMCE and EPS.

Have higher confidence in the forecast for Sat and still have low confidence from Sun-Tue (but slightly favor the cutoff low solution)
as the GEFS ensemble is still very different from the EPS/CMCE (and it isn't just one deterministic run of the GFS that is an outlier).
Showers/tstms eventually become likely across all areas Saturday aftn-Saturday night. The highest chances initially are in the Piedmont during the aftn/evening but move toward the coast by Sat night/early Sunday AM. Highs still in the lower-mid 80s near the coast on Sat, with upper 70s farther inland. A few strong to severe storms are possible on Saturday as well (and shear will likely be higher with the approaching upper shortwave). The main threat will likely be locally damaging winds.

The forecast for late this weekend into early next week depends on the evolution of that shortwave. In general, cooler temperatures are likely regardless of what solution verifies, but the chc for rain remains highly uncertain. If it remains progressive like the GFS/GEFS shows, dry and less humid wx prevails Sunday- Tuesday. If a closed low does form per the ECMWF/CMC, clouds and precip chances will continue through early next week. NBM guidance now has chance PoPs across much of the area from Sunday-Tuesday owing to the trend toward a cutoff low. Hard to pinpoint specifics attm but we could see a widespread 0.50"+ of rain from Sun-Tue night if the cutoff low solution verifies.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
As of 645 AM EDT Wednesday...

Mostly VFR conditions will prevail at all terminals through the 12z/30 TAF period. Expect clear skies outside of SCT-BKN high clouds from dissipating convection through much of the morning.
Then, a cold front approaches from the north this afternoon, with SCT-BKN cumulus and the potential for showers and thunderstorms along and ahead of the front. The most likely timing for convection is between 19-00z at RIC, 21-01z at PHF/ORF, and 23-03z at ECG. Tstms are not expected at SBY. Have maintained PROB30 groups at RIC/PHF/ORF/ECG this afternoon/evening, as brief IFR/LIFR VSBYs and gusty winds are possible in any tstm. Convection should dissipate by 04-05z Thu.
MVFR CIGs are possible late at RIC/PHF/ORF just behind the cold front.

Outlook: Lingering MVFR CIGs are possible across central/SE VA Thu AM, with VFR returning the rest of the day. Isolated tstms likely remain NW of the terminals on Thu. A stronger front approaches the region late Friday, and is expected to move into the area on Saturday. The best chance now appears to be Saturday for widespread showers and storms, but there will be isolated- scattered coverage Friday afternoon/evening.

MARINE
As of 600 AM EDT Wednesday...

Key Messages:

- Small Craft Advisories remain in effect for the Lower Bay, northern coastal waters, and Lower James River early this morning.

- A weak front meanders over/near the local waters today into Thursday with sub-SCA conditions expected outside of any storms.

- Small Craft Advisories again possible from Thursday night into the weekend.

Early morning surface analysis depicted high pressure off the Southeast coast with a cold front approaching from the N. Winds early this morning were SW 15-20 kt with gusts up to 25 kt. As such, SCAs remain in effect across the Lower Bay, far N coastal waters, and Lower James River. Winds quickly diminish later this morning with winds diminishing to 10-15 kt by 10 AM. Winds become light and variable (5-10 kt) this afternoon as the weak cold front slowly moves S across the local waters. Scattered showers and storms with gusty winds are possible this afternoon (mainly late afternoon) into this evening across the local waters (best chance across the lower Ches Bay, rivers, and S coastal waters). Winds remain light into early Thu afternoon as the front lifts back N as a warm front.

At the surface, an area of low pressure tracks from the Midwest into SE Canada Thu into Fri, with an associated cold front approaching the local waters before slowing/stalling. Another area of low pressure forms along the stalled front Sat, helping to push the front across the local waters Sat night. Aloft, a longwave trough approaches the local waters Fri into Sat before likely becoming a cutoff low along or W of the Appalachian Mountains from late weekend into next week. Models continue to slowly trend towards the cutoff low solutions, which would result in a prolonged period of unsettled weather and onshore (potentially elevated) flow next week. While confidence remains low beyond late this weekend, confidence is moderate-high in a period of elevated SW flow (15-20 kt with gusts up to 25 kt) developing ahead of the cold front Thu night into Sat, before winds eventually become NW/N behind the front Sat night. Wind probs for 18 kt sustained winds across the Ches Bay late Thu night into Fri morning were 40-70%. As such, SCAs will be possible with this surge.

Waves and seas were 2-3 ft and 3-5 ft respectively early this morning (3-4 ft seas across the S coastal waters and locally 5-6 ft across the N coastal waters). Waves and seas subside to 1-2 ft and 2- 3 ft respectively later this morning. Another period of elevated seas arrives Fri afternoon into Sat.

AKQ WATCHES/WARNINGS/ADVISORIES
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 9 AM EDT this morning for ANZ632- 634-638.
Small Craft Advisory until 7 AM EDT this morning for ANZ650.