Marine Weather and Tide Forecast for Asheville, NC

KEY MESSAGES
1. Above-average rain chances and below normal temperatures continue through Thursday.
2. A more typical summer pattern begins Friday and continues through early next week with temperatures being around normal and thunderstorm chances being elevated throughout this weekend. Rain and thunderstorm chances dwindle to normal past this weekend and early into next week.

DISCUSSION
Key message 1: Above-average rain chances and below normal temperatures continue through Thursday.

The synoptic pattern remains rather monotonous as a pesky upper ridge remains parked over the Desert Southwest while a Bermuda high builds off the east coast. Farther north, a broad longwave trough extends across the Northern Plains into the Great Lakes region.
Closer to home, over the Southern Appalachians, a weak closed upper low continues to spin over us early this morning but its demise is imminent. As we head through the day, the closed low will evolve into a weak upper shortwave trough and then become completely absorbed into the longwave trough by Thursday morning. Nonetheless, persistent south/southeast return flow will continue to advect plumes of deep moisture into the area that will foster the development of at least scattered diurnally driven showers and thunderstorms. A relative PWAT minimum of 1.5-1.7" is apparent for today, which may limit coverage to widely scattered with the best chance for numerous storms confined to the mountains. On Thursday, a renewed surge in PWATs with values climbing back to 2" will support scattered to numerous showers and storms across much of the area, especially the mountains. As usual, for both today and Thursday, isolated severe weather and flash flooding cannot be ruled out with any summer storm. Low-end thermodynamic parameters with lapse rates just barely above moist adiabatic and moderate instability with a lack of more robust DCAPE will generally preclude a greater severe threat, but any deeper cores will still be capable of producing locally gusty/damaging winds. Same with isolated flash flooding, sufficient deep moisture will be in place but a lack of better forcing and focused convection will keep any flooding threat limited to isolated pockets where locally heavy rainfall is able to fall.
Lower heights and sufficient cloud cover will once again keep temperatures a couple degrees below normal through the period.

Key message 2: A more typical summer pattern begins Friday and continues through early next week with temperatures being around normal and thunderstorm chances being elevated throughout this weekend. Rain and thunderstorm chances dwindle to normal past this weekend and early into next week.

As persistent troughing starts to move out of the area starting Friday, a ridge starts to build in as the Bermuda high off the east coast moves closer to the area. Over this week, there has been a widespread trough over southern Canada which has allowed the Bermuda high to stay up north. Starting early next week, this troughing over southern Canada moves more southeast which flattens the high.
Consequently, this pushes it southward causing a ridge to build in over the eastern US. Across the mentioned period, temperatures are near to slightly above normal and stay in the low 90s with apparent temperatures reaching into the low 100s in some areas. Initially Friday into Saturday, this ridge is less dominant allowing for widespread CAPE being around 1500-2000 J/kg, and the 700-500 mb lapse rates ranging from 6-7 C/km. Rain and thunderstorm chances increase mainly over the mountains with at least scattered storms toward the east. Precipitation chances will range from 80-90% in the mountains and around 20-50% everywhere else. Further into next week, guidance becomes more uncertain as to how pronounced the northern trough builds into the area. While some models show a deeper trough, causing higher precipitation chances, others show lesser chances because the trough isn't pushed farther south. That being said, overall guidance for next week has decreased PoP chances with the mountains only getting up to 40% and some areas east of the mountains less than 10%.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
At KCLT and elsewhere: Areas of low stratus and some fog are ongoing this morning across the area, especially in favored mountain valleys and across the North Carolina foothills and Piedmont. IFR to LIFR restrictions can be expected with this activity over the next several hours with a gradual return to VFR by this afternoon. At least widely scattered showers and thunderstorms are forecast this afternoon into the evening, but coverage may be lower compared to the last few days. Nonetheless, brief impacts cannot be ruled out at any given terminal. Another round of mountain valley fog/stratus is expected tonight with at least some stratus across the foothills and perhaps extending into the Upstate and Piedmont. Winds will be light and variable this morning before shifting to out of the south today.

Outlook: Scattered, diurnal showers and thunderstorms will con- tinue through the remainder of the week, with associated flight restrictions. Patchy fog and low stratus will be possible each morning, especially in the mountain valleys and anywhere that received significant rainfall the previous day/evening.

GSP WATCHES/WARNINGS/ADVISORIES
GA...None.
NC...None.
SC...None.