textproduct: Wakefield

WHAT HAS CHANGED

18z aviation discussion.

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

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 continues to result in poor air quality and reduced visibilities over much of the area.

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

DISCUSSION

As of 340 PM EDT Thursday...

KEY MESSAGE 1...Smoke from Canadian wildfires continues to result in poor air quality and reduced visibilities over much of the area.

Widespread visibility reductions and very poor air quality are in place across most of the area this afternoon. Our MD and VA counties are either in Purple or Red alerts with Orange alert level added to portions of NE NC earlier this afternoon. Visbilities are generally 1-3 miles across MD and VA. The latest guidance from the HRRR and RRFS keep the smoke in the region through the evening before gradually eroding from the south and southeast as winds become SE overnight. Some smoke and/or haze will likely linger into Saturday morning, especially for north and northeastern portions of the area.

Smoke has limited surface heating over much of VA and MD with temperatures mainly in the upper 80s and low 90s. Into NE NC, smoke has been much thinner, resulting in greater insolation and heat indices aoa 105. A Heat Advisory remains in effect for our NC counties until 8 PM this evening. Greater heating has also resulted in a few widely scattered showers and storms along and south of the 'smoke front' (differential heating boundary between smokey vs not smokey areas) in NC. A few strong gusts are possible from this activity but widespread severe wx is not expected.

KEY MESSAGE 2...Thunderstorm chances increase this weekend, bringing the potential for strong winds and 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 significantly less impact tomorrow, though some haze and lingering air quality issues are possible. This will allow hot temps to return, with highs well into the 90s (potentially upper 90s in a few spots) alongside surging dewpoints. Heat indices Saturday are likely to reach 105-108F for much of the area before any convective cooling arrives. Therefore, a more widespread round of heat headlines will be needed. In coordination with neighboring offices, opted to let the current Heat Advisories in NC to expire before issuing additional headlines for Saturday. At this time, it appears that areas near and east I-95 have the best chance for a few hours of 105+F heat indices in late morning and afternoon.

Showers and storms are expected to develop along the lee trough by mid to late 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 25-40 kt range (highest N). Shear is weaker farther S but DCAPE increases substantially into the 1200-1500 J/kg range. SPC maintained the day 2 Slight Risk Risk with damaging wind gusts as the primary threat. Greater shear to the north could support more organized convective structures with some potential for hail or a brief tornado.

Shear weakens a bit on Sunday but sufficient heating and moisture will support a continued strong storm threat across the southern half of the area. SPC has a Marginal Risk from Richmond south and a Slight Risk extending along and south of a line from from South Hill, VA eastward into Hampton Roads. Strong to severe wind gusts are the main threat along with locally heavy rainfall. Hampton Roads has been included again in a Marginal Risk in the latest Day 3 ERO from WPC. 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.

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 /19Z FRIDAY THROUGH WEDNESDAY/

As of 145 PM EDT Friday...

Widespread IFR VSBY due to smoke across the region this afternoon. ECG is the only TAF site that has escaped the IFR smoke conditions. CIGs are mostly MVFR in smoke as well. Expect IFR conditions to continue into this evening before gradual improvement is expected from SE to NW tonight as winds become SE. Smoke or haze lingers longest at SBY and could remain MVFR or lower through most of the period.

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 300 PM EDT Friday...

- Benign marine conditions will persist through Saturday afternoon, though wildfire smoke continue reduce visibility to 1-3 NM into tonight.

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

- Moderate risk of rip currents across the northern beaches on Saturday and possibly Sunday.

Generally light east to northeast winds across the waters as frontal boundary has stalled just south of the area. This has allowed widespread smoke to move across the waters this afternoon with mostly 1-3 NM vsbys. This front will move north later tonight into tomorrow, allowing the winds to turn SE tonight into Sat morning. This wind shift should allow to smoke to move back north by Saturday morning.

SW winds will increase later in the day Saturday and especially Saturday evening ahead of a cold front. Still expecting 15 to 25 kt winds across the waters ahead of this front late Saturday into Saturday night and a small craft advisory will likely be needed. In addition, waves should build to 3 to 5 feet across the waters by Sat night.

The front will gradually move south of the area during the day on Sunday allowing winds to turn E-NE and weaken. Fairly quiet marine conditions are expected Sunday through Tuesday, before S-SW winds possibly increase to small craft advisory levels on Wednesday ahead of the next cold front.

Increasing winds and seas will 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 until 8 PM EDT this evening for NCZ012>017- 030>032. VA...None. MARINE...None.