textproduct: Wakefield

WHAT HAS CHANGED

- Timing for the storm potential today has been further pushed back, generally favoring the evening into early tonight.

- A Heat Advisory has been issued for most of NE NC Monday.

KEY MESSAGES

1) The potential remains for some strong-severe storms, as well as heavy rainfall and localized flooding, mainly this evening into early tonight.

2) Hot and humid with afternoon storms Monday ahead of the next cold front. A Heat Advisory is in effect for most of NE NC.

DISCUSSION

As of 300 PM EDT Sunday...

KEY MESSAGE 1..The potential remains for some strong-severe storms, as well as heavy rainfall and localized flooding, mainly this evening into early tonight.

Quite the interesting sfc analysis across the local region this afternoon. The highest dew points (mid-upper 70s) are situated in the Piedmont with the lowest (mid-upper 60s) closer to the coast. Unsurprisingly, a north-south oriented warm front bisects our CWA and is located just E of I-95 as of 3 PM. Light showers are occuring across the Northern Neck and Eastern Shore with mainly dry conditions elsewhere. Upstream convection is located well NW of the area (across eastern OH and WV).

The widespread clouds and (light) precip across the area have introduced some uncertainty into the storm potential, particularly for this afternoon. Even W of the warm front, satellite imagery is showing quite a bit of clouds. Still, mesoanalysis indicates gradual destabilization is underway with 500-1500 J/kg of MLCAPE across our far western counties. Negligible CAPE is present E of I-95, but this should gradually chance as we head into the evening. It now seems likely that the main show today will be in relation to the aforementioned upstream convection. This activity may not push into the local area until well into the evening hours and the first part of tonight, with a relative lull until then. This later timing also introduces uncertainty into the severe wx potential. Most models still do show relatively impressive shear (for mid-August) of ~30-35 kt this evening and tonight and this will overlap with height falls from a quick-moving shortwave trough. So, some severe risk is still apparent from any cluster or line of storms that can move into our area. The northern half of the area is most favored for both the highest coverage and severe potential, but some risk could extend southward as well. The main risk would be damaging wind gusts, but a few instances of large hail are possible due to the favorable NW flow regime and supportive shear values. MCV- or warm front- augmented low-level shear could also support a low-end tornado threat.

Aside from the severe threat, heavy rainfall is also a concern and slow-moving or back-building storms could result in scattered instances of flash flooding. WPC maintains a Slight Risk ERO covering much of central and eastern VA, mainly north of US-460 and west of the Chesapeake Bay.

KEY MESSAGE 2...Hot and humid with afternoon storms Monday ahead of the next cold front. A Heat Advisory is in effect for most of NE NC.

Hot, humid conditions look to peak on Monday ahead of an approaching cold front, with highs reaching the low to mid 90s. Combined with dew points in the mid-upper 70s, heat indices of 105+ are likely for NE NC and potentially SE VA. Have issued a Heat Advisory for most of our NE NC counties (minus Northampton NC) where confidence is highest in reaching 105+, in effect from 11 AM-8 PM. Later shifts may need to expand the advisory further northward into SE VA if it widespread 105+ indices seem probable. Some scattered showers and storms are also expected Monday afternoon/evening along the lingering frontal boundary and localized severe wind and hail is possible in the strongest storms, mainly for western/SW portions of the local area. Drier and slightly cooler conditions arrive for Tuesday through midweek. A stronger cold front looks the cross the area at the end of week, potentially bringing a more noticeable reduction in heat and humidity.

AVIATION /00Z MONDAY THROUGH FRIDAY/

As of 755 PM EDT Sunday...

VFR conditions are in place early this evening at the main TAF sites. A line of strong convection with gusty winds is approaching RIC from the NW and should impact the terminal over the next hour or two. Timing convection at SBY is a bit more uncertain but have maintained at TEMPO group from 02-05z. PROB30 groups continue for ORF and PHF with considerable uncertainty when or if storms will make it that far SE. Removed the PROB30 from ECG where confidence is even lower. Outside of storms, some MVFR CIGs and/or VSBY could develop overnight, mainly at RIC and SBY. VFR expected for the first half of Monday. Isolated to scattered convection is possible Monday afternoon, mainly over the southern half of the area.

Outlook: Mainly dry/VFR conditions return through midweek as high pressure returns.

MARINE

As of 230 PM EDT Sunday...

Key Messages:

- Small Craft Advisories remain in effect for the Chesapeake Bay and coastal waters N of Cape Charles into tonight due to increasing southerly winds and building seas.

- Showers and storms are also this afternoon into tonight, some of which could be strong to severe.

This afternoon, a weak front is approaching the waters from the SW which is causing the pressure gradient to tighten. As a result, S to SE have started to increase and now average ~15 knots over a majority of the waters. The pressure gradient tightens further this evening into tonight, allowing for winds to become 15 to 20 knots with gusts of 25 to 30 knots. In addition, seas will also briefly build to 4 to 5 feet and will be highest north of Cape Charles on the ocean. Across the Chesapeake Bay, waves will briefly build to 3 to 4 feet. Small Craft Advisories remain in effect for the Chesapeake Bay and the ocean waters north of Cape Charles into early Monday morning. Showers and storms may also produce locally higher wind gusts later an isolated waterspouts later this afternoon into tonight. Wind and seas subside by mid-morning Monday, with generally light flow/benign conditions taking hold for much of the week.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Heat Advisory from 11 AM to 8 PM EDT Monday for NCZ013>017- 030>032. VA...None. MARINE...Small Craft Advisory until 7 AM EDT Monday for ANZ630>632-634- 650-652-654.