textproduct: Wakefield

WHAT HAS CHANGED

- Updated aviation discussion for 12z TAFs.

- Growing confidence in a late summer heat wave building across the area Monday through Thursday.

KEY MESSAGES

1) Morning patchy fog gives way to a mainly dry and seasonable Sunday.

2) Hot conditions prevail during the early to middle portion of the week with increasing chances for showers and storms by late week.

DISCUSSION

As of 255 AM EDT Sunday...

KEY MESSAGE 1...Morning fog gives way to a mainly dry and seasonable Sunday.

Early this morning, high pressure extends from the Great Lakes to the Northeast and is nudging south into the local area. A dissipating stationary boundary is located near or just south of the VA/NC border. North of the front some residual moisture remains in place with dew points in the upper 60s to low 70s. With the residual moisture and calm winds, areas of fog and low stratus are possible this morning. Interior portions of the area and especially the VA Piedmont have the best chances of seeing fog this morning. Any fog quickly dissipates shortly after sunrise.

For this afternoon, high pressure builds over the local area leading to a seasonable and mainly dry day. A stray shower or storm cannot be ruled out across far southern portions of the area due to the lingering boundary, but overall chances are low (PoPs <20%). High temperatures today will be around or slightly above average for late August, with highs expected to range from the mid 80s to around 90.

KEY MESSAGE 2...Hot conditions prevail during the early to middle portion of the week with increasing chances for showers and storms by late week.

A strong 500mb upper level ridge expands eastward over the Ohio Valley and into the Mid-Atlantic early this week. Warm advection and deep mixing will allow for temperatures to rise into the low to mid 90s on Monday and Tuesday (locally upper 90s on Tuesday). Max heat indices on Monday and Tuesday should generally average 100 to 104 due to deep mixing keeping dewpoints in the upper 60s to around 70. Subsidence under the the upper ridge will cap most convective development, limiting any shower/storm chances to <15% (a very isolated shower/storm due to the afternoon sea breeze is possible).

The ridge peaks in strength Wednesday before flattening later in the week. Wednesday will see high temperatures likely in the mid to upper 90s for many inland locations. The NBM even shows a few 100 degree readings across southwest portions of the area, but this is likely too warm and is a known bias. Still, Heat Advisories may be needed for at least southern and southeastern portions of the area on Wednesday, especially if dewpoints overachieve. The ridge begins to break down on Thursday as an upper level trough moves across the Great Lakes and pushes an advancing cold front toward the Mid- Atlantic region. Thursday may be the hottest day of the period due to heating ahead of the front and a slight increase in humidity. Highs on Thursday will range from the mid to upper 90s for most inland locations. Heat Advisories may be needed for much of the area on Thursday. Conditions likely become more unsettled later Thursday and especially on Friday into the weekend as the front slowly pushes into the local area. AI/machine learning tools continue to hint at a severe weather potential on Thursday and Friday, but this will ultimately depend on the timing of the front.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

As of 645 AM EDT Sunday...

MVFR to IFR VSBY restrictions have developed this morning at RIC and PHF, mainly due to patchy ground fog. IFR stratus has also developed over the VA Piedmont, extending just west of RIC. Any fog or stratus dissipates by 13z, with partly sunny skies/VFR conditions expected at all sites through the remainder of the forecast period. An E-SE wind will average 5 to 10 knots this afternoon. An isolated shower or storm cannot be ruled out in the vicinity of ECG later this afternoon/evening, but overall chances are low (PoP <15%). Mainly SKC skies and light winds are expected tonight.

Outlook: Predominately dry/VFR conditions Monday through Wednesday. Shower and storm chances begin to increase Thursday afternoon/evening at all terminals ahead of the next cold front.

MARINE

As of 155 AM EDT Sunday...

Key Messages:

- Generally benign marine conditions continue today and into next week.

Benign marine conditions are still expected today and into next week. Light onshore flow continues for most of today. Later this evening, high pressure slides offshore and a weak boundary lifts back north which will result in winds shifting back to the S/SE. Forecasting a slight increase in winds through the evening hours to 10 to 15kt with strongest winds over northern waters. Going into Monday and Tuesday, winds will generally stay within the 5-10kt range and vary in direction between SW and SE with seabreeze development possible. Sub-advisory conditions and southerly flow are expected to continue the rest of the week as well.

Seas are generally 2-3ft with 1-2 ft waves (highest in the lower Ches. Bay) and will remain 2-3 ft seas and 1-2 ft waves through the forecast period.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...None.