textproduct: Wakefield

WHAT HAS CHANGED

Temperatures have trended cooler Friday and Saturday as a cool wedge airmass develops over the region.

KEY MESSAGES

1) A strong cold front brings the potential for strong to severe storms across far northern portions of the area late this evening.

2) An increasingly unsettled pattern takes shape from Thursday through the Memorial Day weekend. Generally cooler to start, with periods of rain Thursday night and Friday, followed by a low- confidence temperature forecast for the weekend.

DISCUSSION

As of 300 PM EDT Wednesday...

KEY MESSAGE 1...A strong cold front brings the potential for strong to severe storms across far northern portions of the area late this evening.

Storms have started to blossom this afternoon well N/NW of the area (Shenandoah Valley/I-81 corridor) closer to the front where there is better forcing. DCAPE values of ~1300+ J/kg exist over far northern portions of the state over to the MD Eastern Shore. However, the overall motion of the front has slowed down a bit compared to earlier model runs. In addition, there is very dry air at the surface and mid-levels as seen on surface obs and model/ACARS soundings. Given this, it still appears that the better instability and forcing remain to our N/NW. Storm timing over the local area is quite likely to hold off long enough that cells will start to dissipate as they arrive after 00z tonight into early Thursday morning. That said, there remains some potential for a few stronger to severe storms, mainly for far northern portions of the area (Fluvanna/Louisa counties over to far northern portions of Caroline county over to the MD Eastern Shore). Specifically, the best chance of stronger storms likely comes in the event of convective outflows from more widespread storms to our NNW. Damaging wind gusts are the main threat with any storms that can penetrate the area.

KEY MESSAGE 2...An increasingly unsettled pattern takes shape from Thursday through the Memorial Day weekend. Generally cooler to start, with periods of rain Thursday night and Friday, followed by a low-confidence temperature forecast for the weekend.

A shortwave trough is still forecast to eject northeast across the northern Plains and upper Midwest late tonight, pushing into Ontario and Quebec Thursday. This will serve to dampen the SE ridge, while allowing cool high pressure to settle over the Great Lakes and interior Northeast. Meanwhile, the cold front pushes south through the rest of the area Thursday. Still some differences in regards to frontal timing on Thursday, which will have a big impact on temperatures (and possible strong storm chances). If the front crosses the area slower on Thursday, temperatures will be able to warm into the mid to upper 80s over much of the southern half of the forecast area. In addition, there should be enough instability (and marginal shear) to kick off showers and thunderstorms. There is a low-end threat for a few stronger storms, especially near and south of the VA/NC border, where we will be able to get the most heating before the front pushes south. A few stronger wind gusts may be possible, though mid-level lapse rates will be poor, which will help to limit a more widespread severe weather potential. Temperatures will remain cool across the northern half of the area with northeast flow developing in the wake of the front, early highs in the upper 60s to lower 70s are expected before falling back into the lower to mid 60s later in the day.

Increasing overrunning moisture and quickly rising PW values will allow rain chances to ramp up quickly Thursday afternoon, especially along and south of US-58. Showers and scattered storms are expected to develop and focus along the front as it drops across the southern third of the area Thursday afternoon into Thursday evening, eventually settling over the Carolinas on Friday. In its wake, an emerging cool air/CAD wedge setup takes hold for Friday. Forecast highs remain in the 60s to 70s Friday with periods of mainly stratiform light rain and drizzle.

There is still some uncertainty with respect to the durability of the cool air/CAD wedge setup heading into the weekend. Namely, because of the mid-level ridging, there continues to be a growing signal that the warm front remains pinned to our south a bit longer, therefore holding the wedge airmass in place through the first half of the weekend. This injects a bit more uncertainty into temperatures for Saturday, and possibly Sunday as well, as stable, low-level NE marine flow persists. Eventually, the warm front does lift back north over the area to fully erode the CAD airmass later Sunday and Monday. Stagnant flow will then likely result in that weakening frontal boundary getting hung up over northern portions of the area late in the holiday weekend into early next week. This leads to the potential for continued unsettled conditions lingering throughout the holiday weekend. Cooler temperatures than currently in the forecast are quite possible for both Saturday and Sunday, though quick warming is likely heading into early next week as mid- level ridging rebuilds east of the Rockies.

The unsettled pattern will allow for rain chances virtually every day from Thursday through the middle of next week. While the weekend certainly doesn't look to be a washout, rain chances will be higher than they've been of late each day into the middle of next week. The 12z GEFS averages 1.0"-1.5" area wide through Monday, while the EPS averages 1.5"-2.0".

AVIATION /19Z WEDNESDAY THROUGH MONDAY/

As of 150 PM EDT Wednesday

VFR conditions prevail through the daylight hours into the first part of the night. Generally clear skies to start off the period with increasing clouds from the NW later this afternoon and evening ahead of an approaching cold front. Mainly dry conditions are expected outside of a very low chance for a shower or storm at RIC and SBY ~03z. Later tonight into Thursday morning, clouds will continue to lower as the front drops into the local area, with MVFR CIGs reaching SBY ~09z, RIC ~11z, and PHF ~14z (ORF and ECG likely stay VFR throughout the period). CIGs may drop to IFR at SBY, especially after 11z. Rain chances (north) and shower/storm chances (south) also increase late Thursday morning/early afternoon. SW winds ~10kt, with occasional gusts to 20 kt through this afternoon. Winds become NE later tonight as the front drops south.

Outlook: Sub-VFR CIGs (potentially widespread IFR) are likely later Thursday through at least Saturday for a majority of the area as a cool, wedge airmass develops over the area. Sub-VFR may linger through Sunday, especially NW. Conditions also become unsettled with numerous chances for rain later Thursday through a majority of the weekend.

MARINE

As of 300 PM EDT Wednesday...

Key Messages:

- Sub-SCA conditions are expected across the local waters today and tonight.

- A front crosses the waters on Thursday. SCAs have been issued for the bay, ocean north of the VA-NC border, and Lower James River from Thursday afternoon-Friday evening. NE winds will average 15-20 kt with gusts to 25 kt, though gusts to 30 kt are possible on the northern coastal waters.

- Winds gradually diminish and become more variable this weekend, but 5 foot seas could linger across the northern coastal waters.

High pressure remains centered off the SE CONUS coast this afternoon with SW winds of 10-15 kt across the marine area. Similar to yesterday, winds will increase by a couple of knots this evening- early tonight, with a few gusts to 20 kt likely in the bay. A pattern change is finally expected later this week. A cold front approaches the area late tonight into Thursday morning. The 12z guidance has trended a couple of hours slower with the FROPA, which is progged to cross the waters from mid/late Thu AM-Thu aftn. The front is still expected to stall across the NC waters near or just south of the CWA. A period of elevated NE winds is expected from Thu- Fri evening. Wind speeds will average 15-20 kt with gusts to 25 kt north of the VA-NC border...with winds a few knots higher over the coastal waters N of Cape Charles (where gusts to 25-30 kt are possible at times). Winds may struggle to increase as much in the southern waters (especially S of VA Beach) due to the location of the front. Seas build to 4-7 ft (highest N) by Thu night with waves of 2-5 ft on the bay. Have issued SCAs for the bay, lower James, and coastal waters N of the VA-NC border from Thu aftn-Fri evening. Local wind probs for sustained 18 kt winds are still quite high (60- 100% over the advisory area). At this time, the front is progged to slowly lift north Friday night-Saturday morning, which will allow winds to diminish this weekend as the gradient relaxes some. If the front lifts more slowly on Saturday, the northern waters could still see SCA winds linger through Saturday afternoon. Confidence in lighter (~10 kt), more variable winds is high from Saturday night through the remainder of the holiday weekend. However, 5 foot seas could linger north of Parramore Island through much of the weekend even if winds decrease.

There is a moderate rip current risk for the northern beaches (including Ocean City, MD) through this evening, with a low risk elsewhere. With increasing winds and seas associated with the frontal passage on Thursday, all beaches will see a moderate rip current risk. Increasing seas and lingering stronger winds in the wake of the front will produce a high rip risk at all beaches to end the week on Friday. The high rip risk continues on Saturday due to lingering swell.

CLIMATE

As of 300 PM EDT Wednesday...

Tue 5/19: Richmond tied a record high min (71), and SBY also tied the record high min (70). No record high highs were set or tied.

Another day of near-record to record- breaking heat is expected today, both for record highs and record high minimum temperatures. See below for reference.

Record High Temps for Wed 5/20:

Record High/Year Location 5/20 -------- ---- Richmond 97 (2022) Norfolk 98 (1996) Salisbury 98 (1911) Eliz. City 98 (1996)

Record High Min Temps for Wed 5/20:

Record High Min T/Year Location 5/20 -------- ---- Richmond 71 (2018) Norfolk 73 (1996) Salisbury 70 (2018) Eliz. City 73 (2018)

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 1 PM Thursday to 7 PM EDT Friday for ANZ630-631. Small Craft Advisory from 4 PM Thursday to 7 PM EDT Friday for ANZ632-634-639-650-652. Small Craft Advisory from 7 PM Thursday to 7 PM EDT Friday for ANZ654-656.