![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
134 FXUS62 KCAE 172337 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 737 PM EDT Sat Aug 17 2024 .SYNOPSIS... A cold front approaches the Southeast US this weekend along with increasing moisture and rain/thunderstorm chances. A few strong to severe storms will be possible, with better chances on Sunday. Drier air and cooler temperatures are then on tap for early to mid next week. The next chance for rain arrives late in the work week && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Thunderstorms likely in the western Midlands this evening, some damaging wind and hail possible. As the primary mid-level trough continues to dig towards the area, a shortwave and associated forcing is helping fire some convection across northern GA and Upstate SC. Given the synoptic scale trough pushing towards the area, we actually have some notable effective and deep layer shear across eastern GA and central SC, generally between 30-40 knots. Instability additionally is fairly impressive with a broad swath of 1500-2500 ML CAPE over the forecast area thanks to abundant low level moisture and falling mid-level lapse rates. These thunderstorms are expected to push into the Midlands before diurnal cooling helps stabilize things a bit, and diminishes any severe threat. So some scattered damaging winds, especially in Fairfield and Newberry counties, are possible through 11pm and in general, anyone along the I-20 corridor should be prepared for some potentially strong-severe thunderstorms from 8pm through 11pm. The threat after 8pm should transition to more of primary wind threat, rather than hail, as the line grows upscale and becomes more linear. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... Key Message(s): - Scattered afternoon thunderstorms expected, a few of which could produce damaging wind gusts. A bit of a tricky forecast for Sunday. Upper trough over the Great Lakes region is expected to amplify and eject a rather robust mid- level shortwave around its base. This disturbance is progged to move through GA and the Carolinas Sunday afternoon and evening in conjunction with a surface front. Adequate moisture will be available, with PWATs around 1.5"-1.7". Convergence along the approaching surface boundary is expected to be sufficient enough for convective initiation. Given forecast temperatures in the low 90s and dewpoints in the low 70s, SBCAPE between 1500 and 2500 J/kg should generate a broken line of storms along the front. Potential for mainly severe wind gusts will exist, given DCAPE values in excess of 1200 J/kg and 0-6km bulk shear of 25-35 kts aiding in organization. Some model discrepancies exist with the timing of the frontal passage, and the extent of thunderstorm coverage will likely depend on sufficient heating as it moves through. Current thinking is that the eastern half of the CWA is at greatest risk, or mainly east of I-20. This area should have convective elements lining up the best in time and location. HREF members are generally showing initiation in this region, though its possible the strongest storms will be reserved for the Coastal Plain. As the forecast stands now, SPC has placed almost all of the Midlands and CSRA in a Slight Risk for severe thunderstorms. Thunderstorms that do develop will push southeastward along with the front. Behind it, drier air will begin to filter into the area with falling PWAT values and lows around 70. && .LONG TERM /MONDAY THROUGH SATURDAY/... Key Message(s): - Dry through midweek before rain chances return for the end of the week. Next week is relatively quiet compared to the first half of the month. Upper level troughing will remain in place over the eastern CONUS through midweek with drying northwest flow aloft. We`ll still have some lingering moisture near the surface, but dewpoints will be lower, generally in the 60s or perhaps upper 50s, while PWATS will linger between 1" and 1.25". With this stagnant pattern, the front that pushes through Sunday and Sunday night will linger just offshore, with showers and thunderstorms south and east of our area through midweek. Late in the period, deterministic and ensemble solutions are in good agreement that surface high pressure will strengthen over the Great Lakes and move eastward before ridging down the coast. The breakdown of the upper trough is then expected to assist in allowing the offshore front to move back toward the coast. As such, there will be a slight increase in shower and thunderstorm chances at the end of the week, particularly for the eastern Midlands. Overall moisture will still be on the lower side though, so maintained only slight chances for these areas. Temperatures this week will be quite pleasant for August, in the mid to upper 80s with lows in the mid to upper 60s. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR outside of any convection. Broken line of showers and thunderstorms is better organized across much of upstate SC and GA this evening. This activity is forecast to hold together and remain quite organized over the next several hours. Latest guidance does show the thunderstorms approaching the central Midlands and CSRA after 02z this evening, lasting through about 06z. Have gone ahead and introduced vcts between 02z-03z, with a 2-3 hour tempo window for thunderstorm activity with mvfr restrictions at ags/dnl/cae/cub. Not as confident in any of these storms holding together into ogb, so not mention of any thunderstorms in that location. After 06z, remainder of the overnight into Sunday will be dry. Additional convection possible across the eastern Midlands on Sunday, but low confidence at this time. Outside of convection, vfr conditions are expected to prevail through the entire 24 hour taf period. Winds remain gusty this evening before becoming lighter late tonight. Additional wind gusts will pick back up late morning on Sunday. EXTENDED AVIATION OUTLOOK...Scattered showers and thunderstorms are expected Sunday afternoon and evening, possibly strong to severe with restrictions possible. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$