textproduct: Wakefield

WHAT HAS CHANGED

Visibilities have been lowered today in increasing smoke over MD/VA counties. Air Quality Alerts are in effect for MD/VA.

A Heat Advisory has been issued for northeast NC away from the northern OBX. A Slight Risk for Severe Storms is in effect for most of the area for Saturday, mainly for potential late day and evening strong to severe storms. Damaging winds are the primary threat.

KEY MESSAGES

1) Smoke from Canadian wildfires will result in poor air quality, reduced visibilities, and slightly cooler temperatures over much of the area, except over far southern sections where smoke concentration will be lowest. A Heat Advisory has been issued for much of northeast NC today.

2) Thunderstorm chances increase this weekend, bringing the potential for locally heavy rain, along with very warm and humid conditions persisting into early next week.

DISCUSSION

As of 320 AM EDT Thursday...

KEY MESSAGE 1...Smoke from Canadian wildfires will result in poor air quality, reduced visibilities, and slightly cooler temperatures over much of the area, except over far southern sections where smoke concentration will be lowest. A Heat Advisory has been issued for much of northeast NC today.

Very warm and humid conditions continue today. The RRFS and HRRR show waves of near-surface smoke from Canadian wildfires pushing down through the region this morning. This plume will gradually lift out this afternoon and evening, though lingering haze will persist through the night. Haze and visibility restrictions in smoke appear likely today, along with deteriorating air quality; Air Quality Alerts are now in effect for all of our MD and VA counties. The smoke-shading effect will be at play again today, with the near-surface smoke further suppressing solar insolation due to the higher particulate concentration.

Additionally, lower dewpoints on the backside of a weakening frontal boundary have worked into our northern tier of counties and should progress into central and eastern VA before stalling. Consequently, max heat indices should only hold in the 90s for most of the area. However, the southward progress of this boundary looks to get hung up enough to maintain oppressive lower-to-middle 70s dewpoints near and south of the US-58 corridor. Combined with less smoke interference across southern sections, hotter temperatures will yield heat indices rising to Heat Advisory criteria (105F+) in the far south. A Heat Advisory has been issued for our NC counties away from the Northern Outer Banks.

Expect mainly dry conditions today. CAMs show some isolated showers and storms firing along the piedmont trough and riding east along the weakening ridge, which could conceivably make it into south-central VA and interior NE NC before weakening. The best chances for an isolated storm or two remain south of US-460, but probabilities are very low. Kept PoPs capped at 20%.

KEY MESSAGE 2...Thunderstorm chances increase this weekend, bringing the potential for locally heavy rain, along with very warm and humid conditions persisting into early next week.

The upper-level ridge continues to gradually break down and shift off the Southeast US coast over the weekend as upper troughing re-establishes itself over the northern Mid-Atlantic and northeast CONUS. At the surface, low pressure tracking from the eastern Great Lakes into New England will push the stalled boundary back north as a warm front late tonight into Saturday morning, sending its attendant cold front south toward the local area through the weekend. This slow-moving front will likely become hung up and linger across our area into Monday. An influx of deep Gulf moisture ahead of the boundary will push PWs AOA 2.00-2.25" by Saturday afternoon.

Smoke should have a lesser impact on Saturday, though some haze and lingering air quality issues remain likely. This will allow hot temps to return, with Saturday highs well into the 90s (potentially upper 90s in a few spots) alongside surging dewpoints. Heat indices Saturday are likely to reach 105-109F for most of the area before any convective cooling arrives. Therefore, a more widespread round of heat headlines will likely be needed. Given the stifling mid-to-upper 70s dewpoints, there is potential for localized indices near 110F across Hampton Roads and interior NE NC.

Showers and storms are expected to develop along the piedmont trough Saturday afternoon. The first in a series of shortwaves crossing the Eastern Lakes/Northeast will provide adequate forcing for ascent to allow scattered to numerous showers and storms to fire to our west later Saturday, pushing into our area Saturday evening and late night. Given the climatologically favored WNW-NW flow aloft and the highly unstable pre-frontal environment, some organized convective line segments are possible, mainly after 4-6 PM Saturday. Deep-layer shear is respectable ahead of the front in the 25-35 kt range, and SPC has included the entire CWA in a Day 2 Slight Risk with damaging wind gusts as the primary threat.

Due to weakening shear on Sunday, some gusty winds are possible, but the main threat will transition primarily to heavy rainfall along the sagging, weakening frontal zone. Highs Sunday will be slightly cooler but still muggy in the lower 90s (Heat indices 100-105 F), with storms likely re-developing earlier in the day. Hampton Roads has been included again in a Marginal Risk in the latest Day 3 ERO from WPC.

High temperatures trend even cooler into Monday with greater amounts of cloud cover. Additional showers and storms are likely over the southern half of the area, again with locally heavy rainfall as the main threat.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

As of 630 AM EDT Friday...

A thicker plume of wildfire smoke is making its way across the terminals this morning. Expecting conditions to continue to deteriorate more over the next few hours as winds become NE, bringing more surface-based smoke to the area. Models continue to indicate the worst flight conditions today being across northern areas, including SBY, which is already seeing significant VIS reductions to IFR levels at this time. RIC will also likely see VIS drop down to ~2-3SM this morning. ORF and PHF are expected to see reduced VIS through the day too, but likely not as low as RIC/SBY. ECG will see some HZ, but the thicker FU will stay to their north. There could be some locations, especially across the north, that drop to 1SM or less at times. Still not confident on if/when conditions improve later today. Guidance shows winds becoming more SE later this evening potentially pushing the thicker smoke back out of the area, but some haziness will likely linger regardless.

Outlook: Increasing rain chances are expected later Saturday afternoon (highest at RIC/SBY), gradually spreading SE Saturday night. A few storms may be strong to severe with damaging winds, and IFR-LIFR VSBYs will be possible in any storm. Showers/storms are expected to redevelop again Sunday, with additional flight restrictions.

MARINE

As of 320 AM EDT Friday...

- Benign marine conditions will persist through Saturday afternoon, though wildfire smoke will likely reduce visibility today.

- Potential Small Craft Advisory conditions with elevated south/southwest winds and waves expected Saturday night into Sunday ahead of another front.

Benign conditions continue across the local waters early this morning. Winds will become northeasterly throughout the morning as a weak boundary drops through the area, though speeds will remain light. This will also bring in thicker coverage of wildfire smoke, possibly creating visibility restrictions on the water. Confidence isn't high enough now, but if visibility does approach the 1NM criteria, a Marine Dense Smoke Advisory will be issued as needed. For now, think the worst reductions will be across northern waters. Winds will gradually become SE later this afternoon/evening potentially helping push some of the thick surface-based smoke out, but will need to stay tuned to later forecast guidance as things change.

Guidance is consistent with the potential for SCA conditions across the waters Saturday night into Sunday morning as SSW winds increase. Currently forecasting 15-20kt with gusts to 25kt in the Bay and lower James River, with 20-25kt and gusts to 25-30kt offshore. Waves in the Bay will build to 3-4ft with seas increasing to 4-6ft across the northern waters and 3-5ft across the south. Winds and waves look to subside during the day on Sunday.

There is a low risk of rip currents across all beaches today. Increasing winds and seas will likely result in a moderate rip risk for the northern beaches on Saturday. Lingering swells may also require a moderate rip risk for the northern beaches on Sunday.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for NCZ012>017-030>032. VA...None. MARINE...None.