textproduct: Wakefield

WHAT HAS CHANGED

- Slight Risk for Excessive Rainfall across the Piedmont today.

- Marginal Severe Risk for Day 2 (Wed 5/27).

KEY MESSAGES

1) Showers and thunderstorms capable of heavy rainfall are expected today. Additional showers and thunderstorms Wednesday will continue the heavy rainfall threat with also a marginal risk of severe thunderstorms.

2) Drier weather returns to end the week and likely continues into next weekend.

DISCUSSION

As of 335 AM EDT Tuesday...

KEY MESSAGE 1...Showers and thunderstorms capable of heavy rainfall are expected today. Additional showers and thunderstorms Wednesday will continue the heavy rainfall threat with also a marginal risk of severe thunderstorms.

GOES water vapor channels depict an upper ridge over the subtropical western Atlantic early this morning, with an upper trough from eastern TX through the lower Mississippi Valley region. Between these features, a deep moist plume of moisture extends from the Gulf up through the Deep South and eventually rotates across the top of the ridge to the Mid-Atlantic. Locally at the surface, a stationary front extends from SW VA through central VA to the central Delmarva. A very moist airmass is in place with PW values of 1.8-2.0". Heavy rain from showers/tstms dissipated a few hours ago. However, areas of light rain and/or drizzle linger in vicinity of the boundary, along with low stratus clouds.

The stationary front remains over the area today, and may actually nudge a little southward during the day, before slowly nudging back to the N/NE by tonight. The exact position of the front will dictate where the heaviest rainfall falls, and also where tstms are favored. Surface-based instability (and tstms) are likely along and S of the front, with much lower storm chances to the N. Given a potential slight nudge to the S, the best coverage of showers/tstms may initially be S of the highest QPE axis from yesterday, primarily across s-central/SE VA into NE NC. However, as the front begins to lift N/NE this evening the 26/00z HREF does have a modest signal for excessive rainfall across the Piedmont this evening. This area has been placed in a 'slight risk' ERO for today/tonight given that this could fall concurrent with yesterdays heavy QPE axis across the Piedmont. A stronger tstm or two is also possible, but the severe threat is quite low given meager lapse rates and only modest shear. The front's location also has implications on the temperature forecast. At this point, the warmest temperatures are favored from southern VA into NC, though the gradient will probably be a bit more than currently indicated in the forecast.

Showers/tstms dissipate and lift NE tonight as the front retreats to the N/NE along with the loss of diurnal heating. By Wednesday, there will likely to be a mostly dry period in the morning/early aftn, with higher PoPs late in the day into the evening. This timing allowing for increased instability, better low level lapse rates, and somewhat drier air aloft has led to the Day 3 Marginal SVR threat carrying into the new Day 2 period, with 5% probs for damaging winds as the primary threat. Increasing 0-6km bulk shear to 30-40kt and 1500-2000 J/kg of MLCAPE could lead to more organized storm clusters. Additionally, heavy rain will remain a threat as PW values remain 1.8-2.0". Warmer area-wide Wednesday with highs into the mid- upper 80s for much of the area.

KEY MESSAGE 2...Drier weather returns to end the week and likely continues into next weekend.

A cold front arrives from the north Wednesday night, and gradually push south of the area late Wednesday night/early Thursday as a trough digs out of Eastern Canada into the Northeast CONUS. High chc to likely PoPs linger into Wednesday evening (highest E/SE) in advance of the front, but after that an influx of drier air should shut off precip chances into Thursday. Undercut NBM PoPs a bit on Thursday (still maintaining chc PoPs in the south into the aftn). NBM PoPs are mainly 20% or less Thursday, with locally 30-40% in interior NE NC with some low-level convergence and locally higher dewpoints, but these values overall are probably generous. Otherwise, partly to mostly sunny and less humid but due to a well mixed BL, forecast high temperatures remain in the 80-85F range Thursday. Friday will be mild and dry as high pressure settles from the Great Lakes to the local area with highs in the upper 70s to around 80 F inland, and in the mid 70s for coastal areas, after a pleasant morning with lows in the mid 50s to lower 60s.

By this weekend, another trough digs out of Canada and pushes another cold front south across the Mid-Atlantic. However, the latest trends are for a stronger northern stream, which suppress the moisture S. 26/00z EPS/GEFS each depict PW values remaining below normal through the weekend, and even into early next week. For now, NBM PoPs are 20% or less N of the VA/NC border, and 20-30% in NE NC. High temperatures will be below average by about 5-10 degrees, generally in the lower to mid 70s, with lows in the 50s inland and lower 60s along the coast. Overall, quite pleasant for the end of May into the beginning of June.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

As of 700 AM EDT Tuesday...

A stationary front lingered from near RIC to immediately S of SBY as of 12z. Widespread IFR/LIFR cigs were present or developing along the boundary. IFR/LIFR cigs are expected to expand to persist early this morning given abundant low-level moisture. IFR/LIFR cigs should prevail at RIC, SBY, and PHF through the morning, with primarily MVFR at ORF and ECG, with brief IFR possible at ORF through 14z. Cigs largely improve to MVFR later in the morning into the aftn, with IFR persisting the longest at SBY. Additional showers/tstms with heavy rain develop later this morning into the aftn as the boundary lingers over the region. Any showers/tstms have the potential to produce IFR/LIFR vsby in heavy rain. The wind will mainly be calm to light out of the E/NE along and N of the front, and SW 5-10kt to the S of the front. Additional IFR cigs are likely to develop tonight from RIC to SBY as the stationary front lingers across the region.

Outlook: Conditions remain unsettled Wednesday aftn/evening as showers/tstms develop during the aftn and evening (along with early AM CIGs/reduced VSBYs Wednesday morning). A more significant cold front pushes through late Wednesday night night/Thursday, with drier air, N winds and VFR conditions Thursday through Friday. Another cold front arrives by Saturday, but most guidance depicts this as a dry frontal passage with increased northerly winds and VFR conditions.

MARINE

As of 335 AM EDT Tuesday...

Key Messages:

- Marine dense fog remains a concern today, particularly north of Parramore Island on the ocean.

- Sub-SCA winds and seas prevail through most of this week. Thunderstorms could bring locally higher winds and waves today and Wednesday.

The weak frontal boundary that has resided near or over the area the past several days is situated just north of the waters this morning. The wind direction varies from the SW in the southern waters to a light W/NW or variable wind in the northern waters. The light flow and moist airmass continues to exacerbate fog concerns, with < 1 NM visbilities likely present N of Parramore Island on the ocean. A Dense Fog Advisory is now in effect through the early afternoon. Additional fog is possible through the day and could expand southward this afternoon and evening, but confidence is not particularly high. Additionally, showers and isolated storms are again possible today with the highest probability in the lower Chesapeake Bay and S of Cape Charles on the ocean. These will be in association with the aforementioned front, which will slowly drop southward through the day. In general, the SW wind this morning should become rather variable later today with the front nearby. A gradual shift back to the S and SW is then expected tonight into Wednesday as the front lifts back N. Seas average 2-3 ft with 1-2 ft waves in the Chesapeake Bay during this time.

A stronger cold front drops southward across the area early Thursday with the wind becoming northerly. While a brief surge in northerly winds is possible along and just behind the front late Thursday morning, conditions should mostly stay sub-SCA. High pressure builds in from NW Friday with light winds. A stronger system could bring a period of N/NE winds this weekend, with gradually building seas and potential SCAs.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Dense Fog Advisory until 1 PM EDT this afternoon for ANZ650- 652.