textproduct: Wakefield

WHAT HAS CHANGED

No significant changes have been made to the forecast.

KEY MESSAGES

1) Warmer and remaining dry through tonight.

2) Showers and storms return Monday, with some storms potentially becoming strong to severe. A more summer-like pattern takes hold mid to late-week next week.

3) A more summer-like pattern takes hold for mid to late week.

DISCUSSION

As of 225 PM EDT Sunday...

KEY MESSAGE 1....Warmer and remaining dry through tonight.

Surface high pressure over the mid-Atlantic region gradually shifts to the south this evening, as an area of low pressure to our NW approaches the local area. A warm front attached to the low will lift through the region late tonight, with a resulting wind shift to the S-SW. Increasing moisture within the southerly flow is also forecast, with dew points climbing into the upper 60s to lower 70s by Monday morning. Rain will remain out of the forecast today and tonight, returning on Monday.

KEY MESSAGE 2...Showers and storms return Monday, with some storms potentially becoming strong to severe.

First, it is worth noting one substantial mesoscale wild card that could again throw a wrench into Monday's severe and thermal evolution. Latest 12z/21 CAMs continue to track a potential MCS/MCV that could develop this evening and track across N KY and S OH late tonight. While the multi-model consensus is quick to wash out this activity with loss of heating, as is often the case with nocturnal convection, there is some support for some LLJ enhancement that could allow the MCV to push into S WV/W VA by early Monday morning. If this feature can push that far east, its remnant debris cloud shield or at least a stabilized cold pool could spill into our northern and western counties Monday morning. Much like the system that quickly altered expectations late last week, this would more substantially limit morning insolation, strengthening or at least delaying cap erosion, or prematurely forcing early convective initiation along leftover outflow boundaries. While this is admittedly a low probability solution, given the inherent volatility with CAMs, confidence in the exact timing and coverage of Monday's severe threat remains limited until the evolution of this overnight complex becomes clearer.

Provided that wave of convection weakens as modeled, increasingly breezy S-SW winds are then expected by midday Monday in the wake of the attendant surface warm front lifting across the area Monday morning, while a surface low tracks to our N-NW. Gusts of 20-25 mph, up to 30 mph on the Eastern Shore, are forecast during the afternoon outside of any convective development. Increasing moisture may lead to a bit more cloud cover than previous days, but temperatures will still rise well into the 90s, yielding afternoon heat indices in the upper 90s to low 100s.

Forecast soundings show increasing instability by early afternoon, but also highlight some lingering convective inhibition that will need to be overcome. It still appears that rain chances will ramp up after 3 to 4 PM Monday as the cap erodes. SPC has maintained a Slight Risk (Level 2 of 5) for severe weather for most of the area Monday, noting that while the environment could support multiple storm modes, damaging winds remain the primary threat. However, the tornado threat will be relatively maximized across our northern tier of the MD Eastern Shore counties right along the southern periphery of the warm front. Meanwhile, small to marginally severe hail will also be possible area wide within the strongest updrafts.

In terms of storm mode, multicellular storms and bowing line segments are favored at this time. Deep-layer bulk shear is not expected to be overly strong, ranging from ~25-35 kt across the far north, tapering to ~20 kt south of Interstate 64. However, low-level lapse rates will again be quite steep due to very warm surface temperatures, favoring the potential for cold-pool dominated storms with water-loaded downdrafts. Additionally, PWAT values increase to 1.75-2.00" through the day, leading to the potential for locally heavy rainfall. Widespread flooding issues are certainly not expected given very dry antecedent conditions, but we will need to monitor urban and typical poor- drainage areas. Current QPF values range from around 0.25" in the southeast to near 1.00" in the northwest, though localized totals over an inch are entirely possible in the stronger storms. The shower and storm threat will continue through the evening before tapering off overnight.

KEY MESSAGE 3...A more summer-like pattern takes hold for mid to late week.

The front drops across the area on Tuesday, though the timing might be slow enough that southeast VA and northeast NC may still be able to warm up into the upper 80s with dew points in the upper 60s to lower 70s. Most guidance suggests that enough instability will linger across the area, especially near the coast, to support some additional shower and thunderstorm development Tuesday afternoon. This potential would be largely mitigated if the frontal timing ultimately trends a bit quicker, with time. For now, we have maintained low-end rain chances through Tuesday afternoon until better multi-model consensus can be reached.

For the remainder of the week, a more typical summertime pattern sets up for late week. Mainly seasonable temperatures are expected, with diurnally driven, scattered late-day and evening showers and storms possible each day. Expect highs mainly in the upper 80s and low 90s, with overnight lows in the 60s to near 70.

AVIATION /19Z SUNDAY THROUGH FRIDAY/

As of 145 PM EDT Sunday...

VFR conditions at all terminals to begin the TAF period. W-SW winds inland ~5-10 kt, with seabreeze circulations making for more variable winds out of the N-NE at PHF and E-SE at ORF and potentially ECG later this afternoon. Winds veer to the S-SE this evening into late tonight across all terminals as a warm front starts to lift across the area. FEW-SCT high levels clouds are forecast through tomorrow morning.

Outlook: Rain and thunderstorm chances will increase late Monday afternoon through Tuesday. A more typical summertime pattern evolves for the latter half of the week, with mostly VFR conditions. However, but can't rule out a few diurnally- driven late day/evening tstms, with scattered early morning VSBY restrictions due to early morning MIFG also possible.

MARINE

As of 345 PM EDT Sunday...

Key Messages:

- Benign marine conditions continue today and through most of tonight.

- S-SE winds strengthen on Monday ahead of the next system with Small Craft Advisories issued for all marine zones north of the VA/NC border from Monday through parts of Monday night.

Weak surface high pressure remains over most of eastern CONUS this afternoon, allowing benign marine conditions with mostly southerly winds around 5-10 kt. With the light flow, seas breezes are expected. A low pressure system tracks towards the area tonight from the mid-Mississippi River Valley, passing just to the north of the area Monday night. The low will drag a warm front through the area tonight, reinforcing the S-SE flow with wind speeds around 10-15 kt before sunrise. Winds increase to 15-20 kt on the rivers, and 20-25 kt across part of the bay and the offshore waters north of the VA-NC border (with gusts to 30 kt) behind the warm front during the day Monday. Winds will be a few knots less across the NC waters. Wind speeds will peak late Monday afternoon into the early evening before leveling off or diminishing slightly into Tuesday morning. Seas will build to 3-4 ft south/4-6 ft north. Small Craft Advisories remain in effect for all marine zones north of the VA/NC border from late monday morning through Monday night.

Additionally, isolated strong to severe storms are possible late Monday afternoon into Monday evening, which will likely necessitate SMWs. As the low tracks to our north, a weak cold front will cross the waters Monday night. By Tuesday morning, winds will have shifted out of the N-NW around 5-10 kt. Winds will likely increase slightly Tuesday night to ~10 kt with gusts to 15 kt, but looks to stay below SCA criteria in the Ches. Bay. Improving marine conditions are expected Tuesday night through midweek as high pressure returns.

A low rip current risk remains in place today across all area beaches. Monday, the rip risk increases to high across the northern beaches and moderates across VA Beach and Eastern Currituck.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 10 AM Monday to 1 AM EDT Tuesday for ANZ630>632-634. Small Craft Advisory from 10 AM to 10 PM EDT Monday for ANZ635>637-639. Small Craft Advisory from 10 AM Monday to 4 AM EDT Tuesday for ANZ650-652. Small Craft Advisory from 1 PM Monday to 1 AM EDT Tuesday for ANZ654-656.