textproduct: Wakefield

WHAT HAS CHANGED

- Updated aviation discussion for 18z TAFs. Full update for the discussion/marine.

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

KEY MESSAGES

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

2) Cooler temperatures return over Labor Day weekend with decreasing precipitation chances during the second half of the weekend.

DISCUSSION

As of 205 PM EDT Sunday...

KEY MESSAGE 1...Hot conditions prevail during the early to middle portion of the week with increasing chances for showers and storms by late week.

Afternoon wx analysis shows strong upper ridging over the southern Plains with a weak shortwave passing by to our north, and sfc high pressure gradually shifting offshore. Dry and seasonable through tonight with perhaps an isolated shower near the Albemarle Sound from now-early evening. The main story for the next few days will be warming temperatures and potential Heat Advisories by Wednesday/Thursday. The above mentioned strong upper level ridge will expand 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, but an isolated aftn/evening storm is possible on the MD Eastern Shore on both Monday and Tuesday. However, confidence in this is very low.

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 continues to show 100F 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, and potentially even the I-95 Corridor/Richmond Metro. Heights start to fall a bit on Thursday and especially on Friday as the ridge gradually breaks down. An upper level trough is progged to track from the Great Lakes into New England late this week and push a 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. At this time, model consensus shows the front crossing the area sometime from late Friday-Saturday morning as low pressure deepens near Nova Scotia. Isolated afternoon/evening storms are possible (mainly N of I-64) on Thursday with storm chances expanding to the entire area on Friday as the front gets closer to the area. AI/machine learning tools continue to hint at a severe weather potential on Thursday and Friday, but this will ultimately depend on convective coverage. Given how hot it will be, there will likely be a localized damaging wind threat with any storms that do form.

KEY MESSAGE 2...Cooler temperatures return over Labor Day weekend with decreasing precipitation chances during the second half of the weekend.

The upper trough is progged to amplify off the Mid-Atlantic coast this weekend as high pressure tries to build in from the north. This will result in onshore flow, cooler temps, and decreasing precip chances through the weekend. There could still be a fair bit of cloud cover (especially near the coast) with the onshore flow. Highs will generally be in the 80s with lower humidity.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

As of 140 PM EDT Sunday...

VFR conditions are expected to prevail at the terminals through the 18z TAF period with winds aob 12 kt. 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%). SCT- BKN cumulus (3000-4000 ft AGL) will dissipate this evening, giving way to mainly clear skies tonight.

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

MARINE

As of 205 PM EDT Sunday...

Key Messages:

- High pressure translates offshore with sub-advisory southerly flow returning to the region through much of the week.

Surface high pressure is moving over the region this afternoon with yesterday's weak front continuing to lose definition across eastern NC. Winds have mostly switched to southerly but remain locally SE or E close to the coast and in the lower Bay/James River as sea/bay/river breeze circulations strengthen with peak heating. Waves are around 1 ft with seas 2 ft near shore and 2-3 ft in the 20- 60nm zones. Latest guidance continues to show a brief increase in winds to 10-15 kt with gusts to 20 kt this evening, mainly for the Ches Bay and adjacent Atlantic coastal waters. A few gusts may exceed 20 kt in these areas before winds become SW and decrease below 10 kt after midnight. High pressure will dominate the weather pattern over much of the upcoming week with sub-advisory conditions expected. A cold front will approach the region Thursday into Friday with strengthening flow ahead of and (especially) behind the boundary next weekend. Shower and storm chances will ramp up during the late week period ahead of the front. Waves will stay in the 1-2 ft range with seas mainly 2-3 ft.

AKQ WATCHES/WARNINGS/ADVISORIES

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