textproduct: Wakefield

WHAT HAS CHANGED

Added a Heat Advisory for the Albemarle Sound counties of interior NE NC. Otherwise, forecast thinking remains fairly similar.

KEY MESSAGES

1) Heat and humidity persists today across the south, along with isolated to scattered showers and storms area-wide late in the day and into tonight.

2) An unsettled pattern continues through the remainder of the week. However, uncertainty remains high.

DISCUSSION

As of 700 AM EDT Tuesday...

KEY MESSAGE 1...Heat and humidity persists today across the south, along with isolated to scattered showers and storms area-wide late in the day and into tonight.

Early morning WX analysis indicates a W-NW flow aloft with the Bermuda high now getting shunted farther south to the Gulf coast and Bahamas. The latest radar indicates a decaying MCS affecting the northern 1/2 of the area, with a series of trailing systems upstream over OH/WV and another farther NW IA/IL.

With the airmass overturned from yesterday's widespread convection across VA/MD, today's SVR potential is highly uncertain. Debris clouds are likely to persist across at least the northern 1/2 of the CWA through late morning/early aftn which will limit or at least delay instability. The CAMs, which generally did poorly yesterday show varying solutions for this aftn/evening- the 06Z RRFS has backed off with an organized line of storms through the CWA from late aftn into the early evening, now suggesting the main event could be this evening/tonight (which matches closer to the next shortwave aloft). SPC has most of the area in a Marginal SVR risk, primarily for damaging wind gusts, as shear is decent for August (25-30 kt) with a Slight Risk just making it into our far NW. The SPC discussion does note the high uncertainty given the current MCS and how this might affect aftn conditions. In addition, a Marginal ERO is in effect for most of the region (with a Slight nudging into the far NW). The sfc winds are a bit more from the W-SW today, and given this, decided to hoist a small Heat Advisory for the interior NE NC zones along the Albemarle sound where sfc dew pts should be several degrees higher, along with highs into the mid 90s, leading to heat indices of 105+ for a few hrs. Elsewhere, highs will generally be in the lower 90s (upper 80s/around 90F far N with heat indices in the upper 90s to lower 100s).

KEY MESSAGE 2...An unsettled pattern continues through the remainder of the week, trending to a cooler and somewhat drier start to the weekend. However, uncertainty remains high.

WNW flow aloft continues Wed through the remainder of the week as a ridge aloft is expected to continue through late in the week as an upper level ridge builds across the central CONUS, and eventually shifts E-SE across the deep south. Meanwhile, a trough lingers across New England and eastern Canada. Expect an active pattern with the daily potential for isolated to scattered storms each afternoon/evening.

SPC has maintained a marginal risk (level 1/5) for severe storms across southern portions of the FA Wed. However, confidence continues to remain low given uncertainty in aforementioned MCS timing and impacts. For now, have largely kept NBM PoPs (30-35% SW to 15-25% NE) to account for the potential for isolated to scattered storms. Beyond Wed, the pattern remains similar with mostly only a slight chance (15-25%) for a few isolated showers or storms on Thu (and only general thunder risk) with a better chance on Fri (30-40% PoPs). Outside of convection, temps remain near the warm side of normal with highs in the upper 80s to lower 90s Wed and Thu and upper 80s to lower 90s Fri.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

As of 715 AM EDT Tuesday...

Primarily VFR conditions prevail early this morning aside from some local pockets of fog and low stratus over interior SE VA, though none of this has affected any of the main terminals. Mid/high clouds from decaying MCS prevail for the northern 1/2 of the region through late morning, with perhaps a SHRA at SBY through -15Z (have a PROB30), but remaining dry elsewhere. Otherwise, winds will be mainly from the W today at less than 10 kt (ORF could see a shift to the NE for a few hrs this aftn). Storm coverage later today is highly uncertain, but still have mainly 20-30% later in the aftn/early evening, then rising slightly into tonight, so have included PROB30 groups for TSRA at RIC/PHF/ORF/ECG between 22Z through 02Z (though this may need to be trended even later). Showers/storms generally diminishing after 06Z.

Outlook: Expect predominate VFR conditions prevail through Thu. However, daily low-end chances for isolated to scattered showers and storms exists each day. Along with this comes a chance for early morning stratus/ground fog each late night/early morning Wednesday through Friday AM.

MARINE

As of 345 AM EDT Tuesday...

Key Message:

- Sub-SCA marine conditions are expected to prevail through most of the week.

Morning weather analysis shows high pressure continuing to sit well offshore, with a weak surface low over New England. The pressure gradient from these two systems continues to remain weak but just strong enough to keep the winds out of the W around 10kt with some gusts around 15 kt. Seas this morning are around 1-2ft across the bay and 2-3ft across the ocean. Through the morning and into the afternoon of today, winds will shift out of the WSW and remain around 10 kt with gusts nearing 15kt. Seas will remain quite benign and not change much through the day and stay around 1-2ft in the bay and 2-3 ft across the ocean. In terms of storm chances for this afternoon, models continue to back off on scattered to numerous showers and thunderstorms. This is due to the possibility of cloud cover lingering from this mornings ongoing convection to the west. However, if the clouds are able to clear and daytime heating is able to take place the threat for a strong to severe storm cannot be ruled out. The main threat with these storms would be strong winds greater than 34kt. Greater convective coverage is possible on Wednesday but with low confidence on the details. Otherwise, benign marine conditions are expected to prevail through the end of the week.

By the end of the week a cold front will gradually approach and shift winds to the N-NE by late Friday into next weekend. Models are generally keeping the winds rather light, but if the front actually pushes south of the waters, this would potentially bring SCAs, but uncertainty is high at this range.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for NCZ015>017-031-032. VA...None. MARINE...None.