Marine Weather and Tide Forecast for Kilmarnock, VA

NEAR TERM /THROUGH SUNDAY/
As of 310 PM EDT Saturday...

Key Message:

- Hotter and slightly more humid today.

Upper-level ridging is expanding across the southern and eastern CONUS this afternoon as a trough axis slides further offshore.
Surface high pressure is centered just southeast of the region, though it extends well NW into the Mid-Atlantic and Appalachia region. Visible satellite imagery shows scattered cumulus clouds across most of the area as the boundary layer mixes. Temperatures have increased into the upper 80s to around 90 F and high temps should top out in the lower 90s inland and upper 80s at the immediate coast. Dew points are hovering in the mid 60s, which yields slightly muggier conditions compared to yesterday. Still, heat indices will only be a degree or two higher than the ambient air temp.

Slightly warmer tonight given light southerly flow and modest warm advection. Lows in the upper 60s to lower 70s.

Hotter temperatures develop Sunday as ridging expands further and a dome of high pressure settles over the eastern OH Valley vicinity.
The low-level flow also strengthens out of the south as the surface high sets up offshore. 850 mb temps increase to 18-20 C, supporting afternoon high temperatures in the mid-upper 90s, given a well-mixed boundary layer. Dew points also creep up further compared to today, but still remain in the 60s. Peak heat indices are in the upper 90s to around 100 F for the S/SW half of the area, with lower 100s for SE VA and points N and NE. Thus, we still look to stay shy of Heat Advisory criteria Sunday even though a few spots could briefly touch 105 F. SPC also introduced a Marginal Risk (1 out 5 risk level) for the far NE Sunday. Based on all available data, am not expecting any appreciable precip for our CWA but will monitor the progress of any upstream convective complexes Sunday should this thinking change/evolve.

SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
As of 310 PM EDT Saturday...

Key Messages:

- Hotter Sunday with peak heat indices of 98-102 F.

- The peak of the heat is expected Monday and Tuesday with Heat Advisories likely for the entire area.

Overnight lows become progressively warmer as the ridge remains stagnant over the region. Lows Sunday night drop into the lower-mid 70s.

850 mb temps inch up further to 21-23 C Monday as the high pressure ridge/dome aloft strengthens to ~598 dm. This ridge strength is approximately 2 standard deviations above climatology. Meanwhile, high pressure at the surface remains centered near or just south of the area. An (extremely) weak cold front drops south through the area early Monday, but little to no impact is expected from this feature other than a modest wind shift. In fact, PWATs also nudge upwards behind the "front." All of this will set the stage for the beginnings of a prolonged heat wave. Most of the deterministic, statistical, and ensemble guidance is in very good agreement with showing high temperatures in the upper 90s to around 100 F for the entire area Monday. The big question Monday (and the rest of the week as well) is what happens with the afternoon dew points.
Forecast soundings suggest dew points could drop into the upper 60s in the afternoon, though some guidance (such as the NAM/ECMWF)
suggest dew points remain in the lower 70s through the day. The recent wet spell gives some credence to them not fully dropping out.
Still, did drop dew points from the NBM output since they run egregiously high in these setups. Heat indices increase to 104-109 F for most of the area, with the highest values from the Richmond metro into the Northern Neck. A few areas could also near 110 F. All in all, looks like a high-end Heat Advisory for almost all of the area. There was some discussion to issuing these advisories on this shift, but decided to hold off a little longer per collaboration with our neighboring forecast offices. These temps and dew points would also imply strong sfc-based instability; however, strong subsidence from the ridge aloft and warm temps/capping around 750 mb should likely prevent any convective development. Lows Monday night in the mid-upper 70s.

Most of the available guidance is picking up on Tuesday as the hottest days as slightly higher thicknesses and 850 mb temps allow temps to increase to around 100 F for the entire area, with even some lower 100s possible in the urban corridor of central VA.
Afternoon dew points again are an area of uncertainty, but upper 60s/lower 70s dew points and the aforementioned temps yield heat indices in the the 105-110 F range for the entire area. Heat Advisories will be needed with some potential for Extreme Heat Warnings. Dry conditions should persist into Tuesday. However, there will again be strong (mainly capped) instability in place. Should a favorable sea breeze or differential heating boundary set up, there is a very low chance of a pop-up storm. Almost all guidance is dry save the deterministic GFS, which is a high outlier compared to most of its ensemble members. Have 5-10% PoPs in place, but confidence is not high enough for anything more at this time.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
As of 310 PM EDT Saturday...

Key Messages:

- Extended duration heat wave continues through the end of the week.

- Isolated to scattered thunderstorms possible by the afternoon/evening hours of Wednesday, Thursday, and Friday.

The heat wave continues into the middle and end of the week with the prolonged duration (and very warm overnight temperatures)
exacerbating the heat impacts. High temperatures Wednesday through Friday remain in the upper 90s to around 100 F with peak heat indices around 105 F or higher. Additional headlines are a good bet. Overnight lows in the mid-upper 70s are also expected, providing little relief from the heat. The ridge also will break down slightly, allowing the return of isolated to scattered afternoon convection. Given the strong instability, any storm could quickly pulse up and become briefly strong to severe.

Looking back at climate data, Richmond has only recorded 3 or more days in row of 100+ degree high temperatures 13 times throughout the entire climate record dating back to 1871. If this forecast holds, there is a chance that this heat wave will add a 14th time to that list if RIC hits 100F Monday-Wednesday. Also, since 1943 RIC has only hit heat index values at or above 110 six times in the month of June.

AVIATION /19Z SATURDAY THROUGH THURSDAY/
As of 130 PM EDT SATURDAY...

High pressure remains centered offshore today with FEW-SCT CU (5000-6000 ft CIGs ) this afternoon. CU dissipate this evening inland with lingering cloud cover possible at ECG/ORF through tonight. A few afternoon CU will again be possible Sun afternoon. Otherwise, VFR conditions continue with dry conditions. Winds remain S/SE 5-10 kt this afternoon, becoming S ~5 kt tonight. Winds become SW 5-10 kt Sun afternoon.

Dry and VFR conditions are expected to prevail Sun night through the middle of next week as strong high pressure builds over the region.

MARINE
As of 230 PM EDT Saturday...

Key Messages:

- Benign marine conditions are expected through next week.

This afternoon, ~1024mb high pressure was centered offshore with S/SE winds generally 5-10 kt. Winds increase to 10-15 kt with a few gusts up to 20 kt later this afternoon into this evening, eventually becoming SW 5-10 kt late tonight. While a few gusts up to 20 kt are possible, wind probs for 18 kt sustained winds were below 10%. As such, no headlines will be issued. A similar pattern is expected Mon Sun with light SW winds in the morning becoming S/SE 10-15 kt with a few gusts up to 20 kt by late afternoon and evening. A backdoor cold front pushes S Mon, but lacks CAA. As such, light and variable winds are expected Mon. High pressure lingers over the region through the week with generally benign marine conditions expected. Waves and seas remain around 1-2 ft and 2 ft (occasionally 2-3 ft)
respectively through the week. A low rip current risk continues Sun and Mon.

CLIMATE
Daily Record High Maximum Temperatures Sun 6/22-Wed 6/25

Date Richmond Norfolk Salisbury Eliz. City 06-22 101(1942) 99(1981) 98(1988) 98(1942)
06-23 101(1988) 99(2024) 99(1988) 99(2011)
06-24 102(2010) 101(1880) 100(1914) 99(2010)
06-25 100(1952) 100(1952) 99(1914) 100(1952)

Daily Record High Minimum Temperatures Sun 6/22-Wed 6/25

Date Richmond Norfolk Salisbury Eliz. City 06-22 76(2015) 79(2015) 75(1988) 76(1981)
06-23 78(2024) 79(2015) 75(1929) 78(2015)
06-24 78(2010) 79(1994) 75(1969) 76(2011)
06-25 76(1921) 79(1880) 75(1909) 76(1949)

AKQ WATCHES/WARNINGS/ADVISORIES
MD...None.
NC...None.
VA...None.
MARINE...None.