Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, 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
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
237 FXUS62 KGSP 091831 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 231 PM EDT Thu May 9 2024 .SYNOPSIS... A cold front will continue to push east of the area, before another system approaches Friday. Showers and thunderstorms are possible Friday afternoon, before dry high pressure builds in from the north through the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 200 PM: An area of light rainfall is moving quickly across the southeast half of the CWA, associated with shortwave trough. This will be the last gasp of precip for today as the airmass remains worked over from the overnight storms and precip, and subsidence in the wake of the shortwave looks to suppress any new deep convection even after the cloud debris thins/exits later this aftn. Temps have consistently run near the low end of the guidance envelope for today and even where insolation is able to occur temps look to will top out near normal. Tonight, decreasing cloud cover should permit good radiational cooling for a time. Some dry advection will begin overnight, seemingly just enough to maintain a dewpoint depression of a few degrees in the foothills and upper Piedmont, and furthermore some gradient wind is expected to persist. Thus, the likelihood of radiation fog/stratus looks small in those areas. Mountain valleys are likely to see some fog, along with the SE CWA border where the drying is least effective, due to moisture pooling along weak convergence axis. Mins will remain several degrees above normal. More details forthcoming. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... As of 1245 PM Thursday...An upper shortwave axis continues to swing east of the area Fri night as a cP air mass mixes into the lower levels. This airmass will slowly modify warmer over the weekend as a small scale ridge gives way to another diving Canadian h5 trof Sat afternoon. This trof looks to bring it/s own moisture and will probably produce some rain showers across the NC mtns Sat afternoon into the evening. No good chance of thunder during that time as sfc td/s drop into the 40s and potential instability remains nil or quite low. Drier conds with warming temps across the FA Sun as a broad sfc high builds over the area from the west. Generally, both days will be rather pleasant with highs a couple degrees below normal Sat, then back to normal levels on Sun. Mins will likely fall a couple degrees below normal each night. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 120 PM Thursday...A more springtime pattern returns during the ext range. The latest guidance contines to show a subs zone becoming displaced by waves of srn stream energy while a mlvl trof/low travseres the MS to OH valleys. The surface response indicates an opening GOM flow, which will supply a good amt of moisture to a broad frontal system each day. Onset precip timing Mon is suspect with the majority of models indicating a later timeframe than the moister insitu wedge pattern progged by the latest GFS. In any case, thunder probabilty remains low with non-conducive llvl thermal profiles. By Tue, expect a better chance of afternoon thunderstorms as a wavy cold approaches from the west and sfc dewps rise into the u50s to l60s. The pattern remains uncertain, yet possibly active into Wed as another round of srn stream energy may be pushing east across the GOM coastline by then. High Temps remain near normal Mon, then drop abt 5 degrees below normal Tue with the best chance of widespread precip and cloud cover. Highs rebound to normal values Wed. Lows begin the period near climo, then warm abv normal Tue/Wed nights. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... At KCLT and elsewhere: -SHRA over or near the Upstate sites and KCLT through mid-aftn, associated with convective debris. TS not expected thru tonight with airmass already having been stabilized/overturned by the early morning convection, and subsidence increasing aloft reinforcing cap. Some LIFR cigs are forming where rain has ended in NE GA and chance of this reaching KAND is high enough for a FEW LIFR mention this aftn. As high altitude cloud debris advects out this evening and dewpoints fall behind dry cold front, radiational cooling could allow fog/stratus to form with much of the area having saturated soils. Most guidance depicts Td falling slightly more quickly than T, and also light to moderate SW winds continuing, so currently think fog is less likely than a cig, but even the latter not being especially likely. Hence only SCT mention of IFR clouds tonight at KCLT/KGSP/KGMU. A weak upper disturbance may ride over the front late tonight and spawn weak convection between about 10-16z but not confident enough on impacts to mention aside from low VFR clouds at the SC sites and KCLT. An isolated strong or even severe t-storm can`t be ruled out near KCLT in the afternoon, but chance still too small to warrant mention at this range. Outlook: Drier and likely VFR conditions can be expected this weekend. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SBK NEAR TERM...Wimberley SHORT TERM...SBK LONG TERM...SBK AVIATION...Wimberley