Key MESSAGE 1, A hot and slightly drier westerly flow is expected once again today, with afternoon highs topping out in the low to mid 90s. Like yesterday, the slightly drier downslope flow should allow dewpoints to mix out to the upper 60s for some inland coastal plain locations. This is expected to hold heat indices down closer to 100- 103 degrees. Meanwhile, further south (ie. South of HWY 70), dewpoints are not expected to mix out quite as much, especially as the seabreeze moves inland keeping dewpoints elevated. This should support a period of heat indices topping out in the 103-107 degree range there. In light of all of this, a Heat Advisory has been issued for the counties where confidence is highest regarding heat indices reaching 103-107.
KEY MESSAGE 2, A remnant MCV/shortwave is forecast to move offshore of the Carolinas this morning, with a brief period of shortwave ridging and subsidence in its wake. Like yesterday, it's expected that this will tend to limit convection during the late-morning through mid-afternoon period. Later this afternoon and into tonight, another in a line of MCVs is forecast to translate east from the TN Valley into North Carolina. The thinking is that this will lead to another round of scattered bands of convection progressing east across central and eastern NC, primarily with a risk of gusty/damaging winds of 50-70 mph.
In the wake of the late-day/evening convection, a frontal boundary is forecast to settle into the area, with areas of low pressure rippling east along it through Monday. Increasing moisture and lift along the frontal zone is expected to support multiple rounds of scattered to numerous showers and thunderstorms. While the pattern appears kind of messy for severe weather, the frontal zone probably helps to boost deep layer shear some, and there may be at least a marginal/low-end severe risk, especially on Sunday. Additionally, multiple rounds of thunderstorms within a moist environment could lead to some hydro issues. This may especially be the case on Sunday when instability and lift will be maximized, favoring the heaviest rainfall rates and amounts. In light of this, WPC has increased the risk of flash flooding from marginal to slight for much of ENC for Sunday.
KEY MESSAGE 3, In the wake of the active convective period through Monday, a not as hot northeasterly flow regime will develop across the Carolinas early next week, favoring slightly below climo temps. This will offer a brief reprieve from the dangerous heat of late. The reprieve is expected to be short- lived, however, as heat rebuilds late-week.
12z Saturday through Wednesday The next 24 hours are expected to be very similar to the past 24 hours. Sct to BKN mid-level clouds early this morning are forecast to give way to clearing skies by late-morning. It appears that the TSRA risk today will tend to be delayed like it was yesterday, with the risk holding off until after 20-21z. The main difference tonight is that the TSRA risk may last longer compared to yesterday evening. Sub-VFR CIGs and reduced VIS can be expected with any TSRA. Additionally, the strongest TSRA will be capable of 40-55kt downburst winds. In the wake of the TSRA tonight, guidance suggests a period of sub-VFR conditions may develop in either BR/FG or low stratus. There is still some uncertainty regarding how the TSRA will evolve tonight, so for now I've opted to keep conditions VFR.
Outlook (Sunday through Wednesday): An increased risk of TSRA is expected to last into Monday, along with an increased risk of sub-VFR conditions. This is due to a frontal zone and a developing area of low pressure interacting with a moist and unstable airmass over the area. Predominantly VFR conditions are expected to return by Tuesday.
The thunderstorms from last night appear to have disrupted the gradient across the ENC waters, which has allowed winds to lay down slightly. Consequently, this has lowered the risk of 25kt winds for the remainder of the early morning hours, and all Small Craft Advisories have been cancelled early. Later this afternoon into this evening, another marginal risk of 25kt wind gusts appears plausible south of Cape Hatteras and across the Pamlico Sound. However, once again thunderstorms moving through may disrupt the gradient, shortening the potential window of Small Craft Advisory conditions. In light of this, no marine headlines are planned for today or tonight.
Outlook (Sunday through Wednesday): On Sunday, an area of low pressure is forecast to move east along a stalling frontal zone. The low is then forecast to linger of the area through Monday, then shift east by Tuesday. A period of 25kt winds and/or 6ft seas may develop around this low Sunday or Monday, and marine headlines may eventually be needed for a portion of the waters, especially on Monday. Boating conditions are forecast to improve by Tuesday or Wednesday as winds and seas lay down.
Nc, heat advisory from 11 am this morning to 8 pm EDT this evening for ncz090>092-094-193>196-198-199-204-205. Beach hazards statement through this evening for ncz195-196- 199-204-205. Marine, none.
