Key MESSAGE 1, High pressure remains centered offshore this afternoon with some diurnal Cu developing across the region. While moisture continues to stream into ENC, with PWAT's now above 1.75", with a lack of strong forcing and a decent CAP still in place still expect the seabreeze to remain rather quiet with a low end potential (20% or less) of some isolated shower/tstm activity sneaking in from the NW/W in association with some ongoing activity near central VA/NC. Seabreeze continues to work its way inland as of this update as well with SW'rly winds turning to more of a S'rly direction with gusts up to 15-20 mph noted behind the seabreeze today. The bigger issue this afternoon will be the heat. With temps in the mid 90s inland and dewpoints in the upper 60s to low 70s, heat indices around 100-104 are currently noted across portions of ENC. While just shy of typical heat headlines, it is still rather hot so take proper precautions if you plan to be outside today and stay hydrated.
Any leftover shower/tstm activity is forecast to quickly dissipate this evening. With steady SW flow once again tonight, there will not be much relief from the heat with lows in the mid 70s. Once again there will be a threat for some mid and low stratus across ENC as well, though don't think this brings much in the way of impacts to the area and it is a low end chance.
Then as we get into Friday, low level thicknesses increase even further getting to about 1430-1440m which equates to the mid to upper 90s given local studies across ENC. This will threaten records (see climate section below for record high info). With dewpoints once again forecast to be in the upper 60s to low 70s in the afternoon and the slightly warmer temps, heat indices reach 103-108 across our inland zones and given this, we have issued a heat advisory across inland portions of the area away from the coast and OBX which starts up around 11AM and goes to Fri evening. In addition to this, the NWS experimental Heat Risk guidance shows much of ENC in the major category, with a few areas nearing the extreme category which lends further confidence in impactful heat across ENC on Fri. We will cool down slightly in the following days with highs in the low to mid 90s into early next week so while heat headlines are not anticipated at this moment it will still remain rather hot outside, and any precautions you can take if you plan to be outside for longer durations are encouraged. While its a lower end potential (less than 20%) the caveat to the current forecasted heat and heat indices through this weekend will be the coverage of convection (see KEY MESSAGE 2 for additional details), and the potential for high clouds/convective debris. Both of those factors can have significant impacts on the temperature forecast each day.
There does look to be a chance for shower and thunderstorm activity on Fri with the approach of a cold front and seabreeze, mainly during the afternoon and evening. Guidance suggests MLCAPE values will reach 1500-2500 J/kg. While deep layer shear will remain weak less than 25 kts on avg, forcing from the seabreeze and slightly less capping could promote some loosely organized structure in storms. Gusty winds would be the primary hazard if this were to occur. Will note, as long as the midlevel ridge holds on, very warm temps aloft will continue to cap a greater coverage of convection, and thus chances are only 10-20%, so slightly below climo for the afternoon. There is a greater risk after about 7PM of thunderstorm activity and this is noted in Key Message 2.
KEY MESSAGE 2, Synoptic pattern is expected to shift towards something more favorable for convection across ENC this weekend with a weak front crossing the FA SAT and stalling to the S of the area into early next week when troughing aloft develops, opening moisture transport from the Gulf. However, this shouldn't be read as a high coverage of thunderstorms each day. In fact most of the day will be rain free, but as is typical in convective season in ENC, hit and miss storms are going to dot the area each afternoon through early evening.
Stronger showers and thunderstorms develop to our W and approach the area near sunset. This activity is now forecast reinvigorate over the area when the prefrontal trough interacts with the seabreeze as it works over the Coastal Plain. While MLCAPE values may be on the downtrend Fri evening lowering to 1000 J/kg or less by about 9-11PM, ongoing activity could be more cold pool dominated and sustain itself as it enters into ENC. Greatest risk is generally north of Hwy 70 with wind (40-60 mph) being the primary hazard. Spc has also highlighted this area under a marginal risk given the attendant wind threat. Hourly NBM PoPs keep the area under 40-50% PoPs for the first half of the night with lower PoPs (20-40%) over the coast in the early morning hours SAT as momentum carries the weakening showers and storms offshore.
Temps aloft "cool" slightly as heights aloft fall ahead of the front and the stout mid level ridge begins to weaken, and this may support at least a risk of higher coverage seabreeze convection on Sat, particularly along the Crystal Coast seabreeze where likely PoPs are mentioned.
Early next week, higher than climo shower and storm chances are in the forecast with the greater moisture content through the column leading to PWATs in excess of 2". Additionally, deep layer shear of around 30-35kt along the front and low pressure system may support a modest increase in the potential for organized convection, some of which could be on the strong side. High pressure returns late next week when high pressure builds in behind a mid-week front.
00z Friday through Tuesday Pred VFR expected through the TAF period. Decaying thunderstorms across the coastal plain may bring a few showers to PGV and ISO through around 02z but not expecting sub-VFR conditions with them, otherwise expect dry conditions through the overnight. Light to moderate SW winds will keep lower levels mixed and expected to prevent fog development tonight. Model soundings show very dry conditions in the lower levels so the probability for stratus also remains minimal, but cannot rule out patchy stratus along the coast. Sw winds continue Friday with gust around 15-20 kt, especially after the sea breeze pushes through. Could see isolated thunderstorms during the afternoon Friday but converage not enough to mention in the TAF attm. A better chance for showers and thunderstorms after 00z Saturday with an MCS approaching from the NW.
Outlook: Better chance for afternoon/evening showers/storms this weekend when a front crosses the region Sat, stalling to the S and into early next week, with tempo reductions in vsby and/or cigs accompanying the heavier showers and at least a chance of MVFR CIGs directly along the front as it crosses the area early Sat.
No significant changes for today and tonight's forecast as the thermal gradient will ramp up allowing for widespread 10-20 kt SW winds and 25kt gusts across portions of the Pamlico Sound and the Central Waters with 5-15 kt winds and gusts up to 20 kts noted elsewhere across ENC this afternoon. Seas along the coastal waters generally remain around 3-5 ft. As a result ongoing SCA's across the Pamlico Sound and Central waters remain in place into tonight. These conditions will continue into tonight with winds across the Pamlico Sound decreasing closer to 10-15 kts with gusts up to 20 kts out of the SW resulting in SCA's ending here by early Fri morning. Steady SW winds continue with a potentiaL rinse and repeat forecast for Fri across our waters so will be monitoring for the potential addition of SCA's if needed.
Outlook (Fri night through Tue): A typical summertime regime, with swrly gradient flow maxing out between 21Z and 06Z each evening leading to marginal 25+ kt winds gusts in the favored areas mentioned above. Seas of 2-4ft will be common. The risk of thunderstorms will increase Fri night into early next week, with best chances in the late afternoon to evening hours. A front will cross Sat and stall to the S. Low pressure will develop along the boundary and lift back Nward across the Carolinas early next week.
Nc, heat advisory from 11 am to 8 pm EDT Friday for ncz029-044>047- 079>081-090>092-094-193-194-198. Beach hazards statement until 8 pm EDT this evening for ncz195- 196-199-204-205. Marine, small craft advisory until 4 am EDT Friday for amz135. Small craft advisory until 10 am EDT Friday for amz152-154.
