textproduct: Wakefield

WHAT HAS CHANGED

Updated discussion. Added Climate section with record high temp information.

KEY MESSAGES

1) Warmer today, with a small chance for isolated afternoon and early evening showers/storms north of Richmond and over the VA Northern Neck and MD Eastern Shore.

2) Remaining hot and dry, with well above normal temperatures continuing through Wednesday.

3) An increasingly unsettled and cooler pattern looks to evolve for the late week period into the Memorial Day Weekend.

DISCUSSION

As of 320 AM EDT Sunday...

Key Messages:

KEY MESSAGE 1...Warmer today, with a small chance for isolated afternoon and early evening showers/storms north of Richmond and over the VA Northern Neck and MD Eastern Shore.

Temperatures continue to ramp up today. A mid-level trough will drop across the Western CONUS today, driving a building upper- level ridge over the eastern third of the country. Meanwhile at the surface, 1024+mb surface high pressure becomes anchored in the Western Atlantic near Bermuda. Building heights, plenty of sunshine, and strong/deep mixing will all add up to a very warm afternoon across the lower Mid-Atlantic region. There remains strong agreement with models and in-house thickness tools that highs today climb into the lower 90s inland, with highs in the mid to upper 80s along the coast with developing afternoon sea breeze. However, dewpoints mixing out and falling back into the 50s will likely keep the heat index values near or even below the air temperature.

The REFS and past few runs of the HRRR continue to suggest a low chance for some isolated convection over central Virginia, mainly north of Richmond over the VA Northern Neck and the Lower MD/VA Eastern Shore, given forecast MLCAPE values of ~500-700 j/kg. However, given the previously referenced building heights and weak PW values across the region, the atmosphere may remain capped through the afternoon. Certainly, the expectation at this time is that most areas, unfortunately, will remain dry. That said, the lee trough just inland may be just enough of a trigger to allow for an isolated storm or two by 4-6 pm this afternoon, allowing a lucky few to get in on a late day shower or storm. For that reason, have maintained the slight chance (20%) PoPs over the northern third of the area for now. Any showers or storms should quickly clear out within a few hours of sunset, allowing for a clearing and mild to warm evening and overnight. Lows mainly in the 60s to near 70 degrees along the coast.

KEY MESSAGE 2...Remaining hot and dry, with well above normal temperatures continuing through Wednesday.

Summer-like heat makes its presence felt across the region for much of the first half of the upcoming week. Building ridging and minimal low-level moisture should lock in a hot and dry first half of the week. Ensemble guidance continues to suggest broad support for widespread temperatures in the low to mid 90s each day Monday through Wednesday, with H85 temps maxing out between 18-20 deg C. The warmest day looks to be Wednesday, with compressional heating peaking ahead of an approaching cold front. Overall, there remains a very low 1-3 deg interquartile range for Max T each day, indicative of very high model confidence in these temperatures each day. As noted in the first point above, the strong mixing and dry antecedent conditions will continue to allow early morning dewpoints to mix out by afternoon, and fall back into the upper 50s to low 60s each day. This should help to keep a bit of a lid on truly oppressive heat index values, as the heat index is not likely to be much different than the actual temperature.

KEY MESSAGE 3...An increasingly unsettled and cooler pattern looks to evolve for the late week period into the Memorial Day Weekend.

The mid-level trough referenced above lifts across the upper Midwest into eastern Canada by Wednesday. This will serve to dampen the east coast heat ridge, while also allowing cool high pressure to settle over the Great Lakes and SE Canada. it is this feature that will build east Thursday and Friday, driving a cold front through the region Thursday into Thursday night. While LREF probabilities for rainfall >0.50" continue to unfortunately dwindle, now down to 20-50% per the 00z/17 run, model spread in 2m temperatures remains >12-15 deg F for Friday and Saturday across much of the area. This reflects the typical model struggle with the inland extent of shallow marine layers. The current forecast favors high-chance to low-end likely PoPs, which should be mainly stratiform rain and drizzle within the cool, onshore flow. That onshore flow should knock afternoon highs back into the 70s over much of the area through the late week period, with some 60s to low 70s possible in the Piedmont. Lows mainly in the 50s inland to 60s along the coast.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

As of 655 AM EDT Sunday...

VFR conditions currently across area terminals, with VFR conditions expected to prevail through the 12z/17 TAF period. High pressure has moved offshore with winds across the terminals mainly S or SW around 7-10 kt. Winds inland largely stay SSW through the day, though expect some onshore winds from seabreeze effects at ORF by the mid-late afternoon hours (18z and later). Forecast soundings show some moisture around 5000 ft by the afternoon, so expect FEW/SCT CU. Some instability is also noted such that an isolated shower or storm is not out of the question north of KRIC to KSBY, but confidence remains much too low to mention in the TAF.

Outlook...VFR conditions expected through midweek, as high pressure remains in control. South winds each afternoon may gust to 15-20kt as high pressure remains nearly stationary off the coast. Next chance of rain not expected until late Wed or Thursday.

MARINE

As of 315 AM EDT Sunday...

Key Messages:

1) Mainly Sub-SCA conditions are expected across the local waters through at least mid-week with primarily southerly winds.

Expansive high pressure extends across the Southeast, leading to southwest winds across the area this morning. Winds across the local waters have come down a few knots after yesterday evening's surge, with marine-based observation sites measuring 10-15 kts with gusts to 20 kts across the Bay and 15-20 kts across the coastal waters. Seas have continued to struggle to reach their full potential this morning, with only 2-4 ft being observed in the coastal waters, while the Bay is seeing 1-2 ft (2-3 ft at the mouth of the Bay). While Small Craft Advisories are in effect for the VA and MD coastal waters, these will likely be dropped with the next Coastal Waters Forecast update unless measured wave heights start to rise. Guidance does suggest they will start to come down over the next few hours anyways, as winds continue to trend down.

Through mid-week, high pressure will settle into a typical summertime Bermuda High configuration. Winds remain primarily SSW around 10 to 15 kt outside of the daily mid to late- afternoon nearshore seabreeze. The afternoon breeze will likely bring additional localized gusts of 15-20 kt to the lower Chesapeake Bay and nearshore ocean waters each afternoon before winds veer back offshore and diminish through the overnight. Expect generally benign marine conditions to prevail through midweek. The next cold front looks to cross the waters some time early Thursday morning with increasing NE winds late week. At this time, in-house wind probs suggest that even behind the front, only brief marginal SCA conditions are possible and conditions may stay under SCA criteria through next weekend.

CLIMATE

As of 400 AM Sunday...

Record High Temps for 5/17 - 5/20

Record Record Record Record High/Year High/Year High/Year High/Year Location 5/17 5/18 5/19 5/20 -------- ---- ----- ------ ------ Richmond 94 (1974) 95 (1962) 97 (1962) 97 (2022) Norfolk 94 (2017) 95 (1877) 96 (1880) 98 (1996) Salisbury 91 (2017) 96 (1911) 97 (2011) 98 (1911) Eliz. City 95 (1941) 93 (1987) 95 (1996) 98 (1996)

Record High Min Temps for 5/17 - 5/20

Record Record Record Record High High High High Min T/Year Min T/Year Min T/Year Min T/Year Location 5/17 5/18 5/19 5/20 -------- ---- ----- ------ ------ Richmond 69 (1990) 72 (2015) 71 (1997) 71 (2018) Norfolk 72 (2018) 75 (1995) 72 (2017) 73 (1996) Salisbury 69 (1974) 71 (1953) 70 (1929) 70 (2018) Eliz. City 70 (2018) 73 (1995) 72 (2018) 73 (2018)

AKQ WATCHES/WARNINGS/ADVISORIES

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