Marine Weather and Tide Forecast for Kilmarnock, VA

KEY MESSAGES
1) Hot conditions with moderate humidity levels prevail for the remainder of the week, along with mainly dry conditions.

2) Waves of smoke from Canadian wildfires will push into the area later today through late this week.

3) Increasing thunderstorm chances this weekend, with very warm and humid conditions persisting into early next week.

DISCUSSION
As of 245 AM EDT Wednesday...

KEY MESSAGE 1...Hot conditions with moderate humidity levels prevail for the remainder of the week, along with mainly dry conditions.

The latest analysis indicates a potent and anomalously strong (597+ dm) upper level ridge centered across the Mid-Mississippi River Valley and an upper trough over Atlantic Canada that has pivoted well offshore of the Northeast and Mid-Atlantic coast.
At the surface, high pressure is located over the region, with deepening sfc low pressure over Atlantic Canada.

Temperatures warm up a bit more today as the strong upper level ridge expands E-SE into the local area, allowing heights to rise along much of the eastern seaboard. Locally, humidity levels look to stay moderate, keeping afternoon heat indices from rising much above ambient air temperatures. However, with the core of the ridge centered across northern areas today, the hottest temperatures and heat index values look to remain over the VA Northern Neck and the Maryland Eastern Shore. Afternoon dewpoints look to mix out into the upper 60s, but with highs around 100 F, still anticipate seeing a 3 to 4 hour period this afternoon with heat indices near 105 F. For that reason, a Heat Advisory remains in effect from Caroline Co. east across the Northern Neck and into the MD Eastern Shore and Accomack (VA).
Eastern King William, Gloucester, and Mathews counties have been added to the Heat Advisory with this package.

Given the referenced Canadian low pressure and a cold front trailing the deepening cyclone to our north approaching, increasing W-SW low-level flow should push hot temperatures all the way to the Atlantic coast (including Ocean City and Wallops), with highs in the upper 90s to around 100. Areas to the south will mix out a bit more, allowing dewpoints to lower into the 60s and yielding heat indices right around 100 degrees.

Tomorrow still looks to be the hottest day of the week, with widespread readings in the upper 90s to around 100F over much of the local area, though slightly cooler over southside Hampton Roads into northeast NC, farther away from the core of the heat ridge. Another round of Heat Advisories are likely to be needed over the same northern areas tomorrow and will also probably need to be expanded south to at least the Richmond/Tri-Cities area and much of Hampton Roads. Convection should remain suppressed away from the area through most of Thursday, though we will maintain a slight chance (~20%) PoP Thursday evening across the MD Eastern Shore, as upstream convection approaches from the north before washing out. On Friday, temperatures will likely be a little cooler over the north and along the coast and the Eastern Shore. Additional Heat Advisories may be needed across south- central and SE VA into northeast NC. A low chance for isolated showers/storms moves in from the NW Friday evening, as isolated convection riding along the ridge could make it into the area before weakening.

KEY MESSAGE 2...Waves of smoke from Canadian wildfires will push into the area later today through late this week.

As if the returning heat and humidity weren't enough, waves of dense smoke aloft emanating from wildfires over west-central Ontario will push south toward the area later today and intermittently over the next few days. The smoke shows up well on early morning GOES imagery, getting funneled SE into the region along the eastern periphery of the building upper ridge.
CAMs (HRRR/RRFS) indicate a bit more smoke pushes in later today and tonight, but remains mainly well aloft for now.

However, as the ridge breaks down in the coming days and stronger WNW-NW flow aloft develops, it is possible some near- surface impacts could develop, namely air quality issues and visibility restrictions in haze by Friday. An Air Quality Alert has been issued for Maryland for today, including the MD Lower Eastern Shore. Additional alerts are possible later this week and we will continue to monitor potential further impacts in the days ahead.

KEY MESSAGE 3...Increasing thunderstorm chances this weekend, with very warm and humid conditions persisting into early next week.

The upper level ridge continues to gradually break down over the weekend as upper troughing re-establishes itself over the northern Mid-Atlantic and northeast CONUS. A series of shortwaves will track across the area from Saturday through Monday ahead of the next front approaching from the north. It now seems likely that this weakening front will linger across the area into Monday.

While considerable uncertainty remains regarding the exact timing and coverage of storms, the upper flow turning WNW-NW over a hot, increasingly humid, and moisture-pooled boundary layer sets up a climatologically-favored pattern for locally heavy rainfall and downbursts. Low-level frontal forcing still appears weak, typical of mid-July, but moisture pooling along the slow-moving boundary beneath steep mid-level lapse rates will favor a hot, muggy, high DCAPE setup capable of producing isolated to scattered damaging wind gusts each day this weekend, potentially lingering into Monday. Areal coverage of these storms will ultimately depend on the timing of each shortwave, which remains highly uncertain at this time range.

High temperatures trend a bit cooler with the increasing PWs and cloud cover. However, with that comes higher dewpoints. This appears especially likely across SE VA and NE NC, where max heat indices will likely linger near 105 F through Sunday, if not Monday.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
As of 650 AM EDT Wednesday...

VFR conditions are expected to prevail across all terminals through the 12z TAF period. Light SSW winds increase to 7-10 kt later this morning into this evening. Will note there is some high level smoke from Ontario wildfires that approaches from the north later today and especially tonight, but should not impact flight condition yet.

Outlook: Dry conditions prevail through late this week. An isolated SHRA/TSRA possible at SBY Thu evening. High-res guidance indicating an increasing chance for VSBY restrictions in haze/smoke on Friday morning/afternoon. Another chance of isolated showers/tstms mainly west of KRIC on Friday, with better chances area wide coming later Saturday and Sunday.



MARINE
As of 245 AM EDT Wednesday...

- Benign marine conditions are expected into late week with high pressure focused near the area.

An elongated area of high pressure remains in the vicinity of the local waters early this morning. Winds are currently SW 10-15 kt with gusts up to 20 kt across the local waters. There will be a slight decrease in winds during the day today with SW winds around 5- 10 kt before increasing again overnight tonight into Thursday with 5- 10 kt with gusts to 15 kt in the Ches. Bay and 10-15 kt with gusts to 20 kt over the coastal waters. The high pressure will remain near the area through Thursday, allowing for sub-SCA conditions to prevail with S- SW winds. A weak frontal passage remains possible Thursday into Friday, but now looks to lose the forcing before making it through the local waters. A wind shift to the E-NE Friday is possible, more likely for the northern waters than the southern waters. Southerly flow could approach SCA thresholds Saturday night into Sunday morning ahead of a frontal system. Seas will generally be around 2 ft through the end of the week, increasing to 3-4 ft as S winds increase later Saturday.

There is a moderate risk for rip currents across the northern Outer Banks, NC today with a low risk elsewhere. A low risk is favored everywhere Thursday and Friday.

CLIMATE
As of 650 AM EDT Wednesday...

- Record Highs:

- Today 7/15 Thu 7/16 Fri 7/17

- RIC: 100 (1995) 101 (1980) 100 (1980)
- ORF: 101 (1995) 102 (1879) 100 (1887)
- SBY: 100 (1995) 99 (1915) 99 (2012)
- ECG: 97 (1997) 98 (1995) 99 (1942)

- Record High Mins:

- Thu 7/16 Fri 7/17

- RIC: 77 (1983) 77 (2025)
- ORF: 80 (1995) 80 (2024)
- SBY: 78 (2024) 80 (1983)
- ECG: 79 (2012) 80 (2019)

AKQ WATCHES/WARNINGS/ADVISORIES
MD...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for MDZ021>025.
NC...None.
VA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for VAZ064-075>078-084>086-099-517>522.
MARINE...None.