Key MESSAGE 1, Hot and humid conditions prevail this afternoon with NW flow keeping the sea breeze pinned to the coast. Temperatures have reached the mid 90s away from the immediate coast with upper 80s to lower 90s along the coast. Dew point temps in the mid to upper 70s have allowed heat indices to climb to around the 105-115 degree range. The Extreme Heat Warning and Heat Advisory remains in effect through 00z this evening.
Wednesday will see slight relief from the heat with a frontal boundary stalling just off the coast overnight bringing N to NE winds into Wednesday morning before the sea breeze becomes dominant later in the afternoon. Temps expected in the upper 80s/lower 90s northern tier with heat indices peaking around 100-105, however southern sections of the forecast area will see temps reach the mid 90s with heat indices around 105-110 and have issued a Heat Advisory for Pamlico, Craven, Carteret, Jones, Onslow and Duplin Counties. A return to S/SW flow across the area Thursday will bring a greater area of heat indices around 105-110 and will likely see another Heat Advisory for much of the area. A frontal boundary drops into the are Friday bringing greater cloud coverage as well as coverage of storms and expect Heat Indices to remain below criteria.
KEY MESSAGE 2, NW flow has kept the sea breeze pinned to the coast this afternoon with limited convection across ENC so far, however a few thunderstorms are beginning to develop across Mainland Dare Co. Additionally, widely scattered thunderstorms are pushing across NE NC associated with a subtle shortwave and weak cold front moving north of the area. Convection this afternoon is generally expected to be confined to coastal sections along the sea breeze and northern counties as the weak front drops into the area and should dissipate during the evening with loss of heating. The front weakens with the sea breeze becoming dominant and making a farther push inland Wednesday afternoon. Precip chances generally remain around 20-40% 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. Otherwise, overall severe threat is low - less than 5%.
Continued moist and unstable on Thursday with a mid level shortwave pushing across the region bringing a slight increase in shear to around 25 kt which may allow for stronger storms. Spc has a marginal risk (Level 1 of 5) for severe storms with damaging wind gusts the primary severe threat.
KEY MESSAGE 3, Deeper trough begins to dig across the Ohio River Valley on Thursday and push towards the Eastern Seaboard on Friday and into the weekend with a cold front stalling across the region. Favorable jet dynamics, moist SSW flow aloft along with a series of shortwave trough the upper level trough will bring high chances of showers and thunderstorms late in the week and into the weekend. Greater cloud coverage will likely limited strong instability and storms are generally expected to be sub- severe, though heavy rainfall will continue to be a threat with PW values greater than 2".
18z Tuesday through Sunday Pred VFR conditions through the evening with isolated thunderstorms potentially bringing brief sub-VFR conditions, though most storms are expected to remain east of the TAF sites. A front will push south through the area this evening with weak N to NE flow developing. Guidance generally keeps fog potential fairly low, less than 30 percent but the chances for stratus is a bit higher with HREF probs for IFR cigs around 40-70 percent. Not all guidance develops stratus, however, and limited low cloud coverage to sct in the TAF for now. If stratus does develop, it will dissipate around mid morning. Widely scattered thunderstorms possible again Wednesday afternoon.
Outlook (Wednesday night through Sunday): Pred VFR expected through Thursday though isolated to widely scattered diurnally driven seabreeze shower and thunderstorm activity may bring brief sub-VFR conditions. 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.
Generally light winds across the waters through Wednesday with a weak cold front temporarily dropping into the area tonight into Wednesday morning bringing N to NE winds less than 15 kt. The front will dissipate Wednesday with the sea breeze becoming dominant bringing SE winds across the waters. Seas will continue around 2-3 ft. 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 until 8 pm EDT this evening for ncz029-044>046- 079-080-091-092-193-203>205. Extreme heat warning until 8 pm EDT this evening for ncz047- 081-090-094-194>196-198-199. Heat advisory from 11 am to 8 pm EDT Wednesday for ncz090-092- 094-193>196-198-199. Marine, none.
