Key MESSAGE 1, Latest surface analysis shows a surface trough currently moving east across the Coastal Plain this morning with a slow moving cold front still well off to the west near the Appalachians. This cold front will take its time to get to ENC today but will likely weaken as it approaches which won't produce much change in the airmass across the area over the next few days, but may help to focus shower and thunderstorm activity along the seabreeze. As mentioned above, with a lack of airmass change our area and much of the southeastern CONUS remains in the grip of a very hot and humid airmass.
It is warm and muggy this morning with temps in the 70s to low 80s. Much like yesterday, hot and humid conditions are once again expected today as temps climb into the mid 90s inland with upper 80s to low 90s along the immediate coast and OBX this afternoon. However, unlike yesterday where there was little to no relief provided by convection, today will be a bit more active day and many areas could be convectively cooled by this evening. Still, at least some period of HI of 110-115F is likely especially along the seabreeze with widespread 105-110F values elsewhere. As a result have kept previously inherited Extreme Heat Warnings and Heat Advisories in place today starting at 11AM and continuing into 8PM tonight.
As we get into Wednesday and Thursday, aforementioned front will remain stalled along the coast. While cooler northeasterly flow will likely keep the most oppressive heat at bay from the Outer Banks to Albemarle Peninsula, areas south of US 264, and particularly south and west of US 70, will likely still see an elevated risk of HI between 105-110 each afternoon. A more widespread cooldown is likely Friday into the weekend as a stronger cold front nears.
KEY MESSAGE 2, Currently have a mid level shortwave moving through ENC this morning with associated surface trough pushing east towards the coast. We do have some ongoing shower and weak thunderstorm activity noted along and north of Hwy 264 associated with this trough also pushing east. Outside of a stray gust to 40 mph, the main threat with these storms will be torrential downpours and frequent lightning. With a more stable airmass as you get closer to the coast and any leftover activity is forecast to weaken and eventually dissipate out near the OBX and coastal waters near daybreak.
Overall there will not be significant changes in the pattern into Thursday. Zonal flow will continue across the Mid-Atlantic through Wednesday as an upper ridge remains centered to our south and an active northern stream jet remains to the north. This will change however on Thurs into Fri as upper level winds turn to a SW'rly direction out ahead of an incoming trough. At the mid levels, weak shortwaves will track across ENC daily, with the first of such moving across the area this afternoon and evening, and another shortwave pushing through Wed afternoon. At the surface, the aforementioned front eventually stalls near the coast and combined with an inland moving seabreeze, this will be the focal point for shower and thunderstorm activity today and tomorrow. Main corridor today for shower and thunderstorm activity looks to be along Hwy 17 corridor and points east with just isolated chances further to the west. As we get into tomorrow, this threat likely pushes further inland with the seabreeze as the afternoon wears on. Precip chances generally remain around 20-40% each afternoon and evening before chances decrease after sunset. Despite poor shear, high PWATs exceeding 2.25" are expected and a stronger cell could pose an isolated wet microburst threat this afternoon and tomorrow. Otherwise, overall severe threat is low - less than 5%.
KEY MESSAGE 3, Deeper trough begins to dig across the Ohio River Valley on Thursday and push towards the Eastern Seaboard on Fri and into the weekend. Stronger shortwave will also be transiting along this trough bringing a stronger cold front to ENC this weekend, though latest trends suggest as this front nears the area it also will stall and weaken. Either way this front will bring a much welcome pattern change serving to both offer a reprieve from oppressive heat and humidity and a chance of strong to severe thunderstorms as shear increases alongside the boundary with stronger troughing. Details are coming into better focus but there are still some details to hammer out in the coming days such as frontal timing and strength. Will continue to monitor trends in the forecast for any adjustments in the coming days. Ncar medium- range AI NWP guidance continues to suggest at least modest probabilities (around 5%) of an environment favorable for strong to severe convection.
12z Tuesday through Saturday Primarily VFR flight cats are noted across ENC this morning. Showers and thunderstorms that had impacted areas north of Hwy 264 have since dissipated and just some patchy ground fog has been seen this morning, mainly located along the Crystal Coast and ISO TAF site. Expect any leftover ground fog to dissipate within the next hour or so. But, with leftover ground fog over ISO, have elected to issue a TEMPO group to account for the threat here through 13Z.
Once the rest of the patchy ground fog dissipates, VFR conditions are forecast this morning. However, as we get into the afternoon and evening a combination of the daily seabreeze and a stalling front will likely promote convective activity this afternoon and evening. Much of this activity will likely remain around and east of Hwy 17, and as a result have kept PROB30 groups in for EWN/OAJ TAF sites this afternoon. Within any thunderstorm, MVFR to IFR ceilings/vis are possible. We remain mainly dry across ISO/PGV TAF sites and surrounding areas so have no precip mention here. Any precip chances end near sunset with the loss of daytime heating. Once again, guidance is hinting at the potential for some patchy fog and maybe some low stratus tonight mainly after 06Z. However, much like the last several nights guidance may be too pessimistic. To account for this uncertain threat have just included a FEW009 cloud deck at the TAF sites for now and will have to monitor trends as we get closer to this evening to get a better handle on the potential sub-VFR threat. Outside of thunderstorm activity, winds remain light.
Outlook (Wednesday through Saturday): Expecting primarily VFR conditions through Thurs. The lone exceptions would be under isolated to widely scattered diurnally driven seabreeze shower and thunderstorm activity each day. No significant fog or low stratus concerns each night either but trends will have to be monitored in case the threat increases in the coming days. Yet another front begins to approach from the west Friday once again bringing increased shower and thunderstorm risks as well as increasing risks for sub-VFR conditions into this weekend.
No real changes in the marine forecast as outside of any shower or thunderstorm activity over the next few days winds and seas will remain rather benign across our waters. Have ongoing 15-20 kt SW'rly winds and 2-3 ft seas noted this morning across all waters. Do have some ongoing shower and weak thunderstorm activity currently impacting the inner rivers and sounds this morning, but outside of frequent lightning, minimal impact is forecast. This activity is forecast to weaken and dissipate near daybreak today. Expect winds to ease down to 5-10 kts by this evening with the approach of a stalling cold front. These light winds persist through the rest of the period. Seas wont chance much either maxing out around 2-3 ft across our coastal waters into Wed. Outlook (Wednesday through Saturday): Benign boating conditions persist through Wed and Thurs with eyes to next potential SCA Fri and into Sat with a stronger frontal boundary. Each day will bring a low to moderate risk (20-40%) of showers and thunderstorms to area waters, with increasing chances into the weekend.
Nc, heat advisory from 11 am this morning to 8 pm EDT this evening for ncz029-044>046-079-080-091-092-193-203>205. Extreme heat warning from 11 am this morning to 8 pm EDT this evening for ncz047-081-090-094-194>196-198-199. Marine, none.
