Sunrise 6:06 AM   Sunset 8:35 PM Moonrise 2:21 AM   Moonset 3:35 PM

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FXUS62 KGSP 021855 AFDGSP

Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 255 PM EDT Sun Jun 2 2024

SYNOPSIS
A typical summer pattern is returning during the first half of the week with daily afternoon thunderstorm chances. Showers and thunderstorms will likely increase in coverage for Wednesday and Thursday as a weak cold front approaches our area. Drier weather is expected to return by the end of the week.

NEAR TERM /THROUGH MONDAY/
As of 2:25 PM Sunday...shower coverage remains widely sct across our fcst area this afternoon with little in the way of any thunder yet observed. We are beginning to see some breaks in the cloud cover over our southern zones, so I expect we will start seeing more discrete cells develop as instability increases over the next few hours. As for the severe potential for the rest of the day/evening, it's still pretty much zero for our CWA Showers will gradually move east of our area later tonight/overnight with low temps dropping to near-normal if not slightly above. With winds going light to calm and ample lin- gering boundary layer moisture, there's a good chance that we'll see at least patchy dense fog across our area with widespread fog certainly possible by daybreak.

Otherwise, an upper shortwave trof will translate over our fcst area and help push a weakening upper ridge off the Atlantic Coast today/ tonight. As we move into Monday, heights begin to rebound as upper ridging starts to build over the Southeast again. At the sfc, high pressure will continue to slowly move further off the SE Coast as a moist frontal boundary gradually moves thru our fcst area today and tonight and eventually washes out to our east on Monday. This will result in profiles undergoing some amount of drying on Monday. None- theless, we will remain under warming SLY low-level flow which will likely produce another round of diurnal, isolated to sct showers and thunderstorms, yet the severe potential still appears minimal at best on Monday. In addition, temperatures on Monday will rebound to near, if not slightly above, normal values under significantly less cloud cover and increasing thicknesses.

SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
As of 130 pm Sunday: A weak short wave ridge will meander across the region through much of the period, before shunting to the Coast by Wed evening, as an area of large scale height falls overspreads the Appalachians and vicinity. SW low level flow will provide the heat and humidity for diurnal deep convection Tue afternoon...although coverage is expected to be somewhat limited due to weak anticyclonic flow aloft and relatively low precipitable water values. Moderate instability should nevertheless allow for isolated to widely scattered coverage (20-40 PoPs) across much of the area, esp the high terrain.

A cold front associated with aforementioned height falls will enter the picture from the west by the end of Wednesday, enhancing diurnal convective chances during the afternoon/evening, especially over the mountains, where 60-70 PoPs are warranted. A consensus of short term guidance suggests destabilization could be quite robust Wed afternoon, with sbCAPE of 2000+ J/kg likely. Shear parameters are forecast to be quite meager, but 0-3km shear of 15-20 kts could support some local cell clustering along outflow boundaries which would pose a threat of isolated downbursts, while a few pulse severe storms also appear to be a good bet. With the front expected to steadily cross the region Wed night, some degree of convective coverage will likely persist long after the end of the diurnal heating cycle, albeit with a warning risk of strong-to-severe convection. Temps are expected to be a category or so above climo through the period.

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
As of 150 pm Sunday: A trough associated with a deep upper low is expected to develop across the East early in the extended...
gradually shifting off the East Coast through the period. An associated frontal boundary is expected to be draped over or near the forecast area at the start of the period, with scattered convection (generally 30-50 PoPs) expected from late morning through the afternoon Thursday. Lower theta-E air is expected to begin filtering in from the west by the end of the day, bringing an end to substantial convective chances from Friday through next weekend, although a few showers (PoPs 30% at most) will be possible across the mountains within deep NW/upslope flow regime Friday through Sunday. Other than a stretch of near-to-slightly below normal temperatures expected Fri night through Sat night, temps are expected to remain a category or so above normal through the period.

AVIATION /19Z SUNDAY THROUGH FRIDAY/
At KCLT and elsewhere: Sct showers with some embedded thunderstorms are expected to linger over the fcst area thru the afternoon and into the evening. Have TEMPOs for thunder at all taf sites until roughly 24z with some lingering vcsh after that. After the rain moves east of our area later tonight/overnight, expect cigs and visby to lower.
I think there's a decent chance that all of our taf sites (except for KCLT) will see a few hrs of IFR cigs and at least MVFR visby overnight and into the morning. KAVL has the best chance of seeing LIFR or lower around sunrise. Expect visby to improve and the lower cigs to sct out by roughly 14z late tomorrow morning with VFR for the rest of the day.
We will likely see another round of diurnal isolated to sct convection Monday afternoon/evening, which I have mentioned in a PROB30 for KCLT beginning at 20z. Otherwise, winds will go light to calm later tonight/ overnight and continue to favor a S to SW direction on Monday.

Outlook: Diurnal shower and thunderstorm chances with associated restrictions will linger thru the middle of next week.

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

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