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
799 FXUS62 KGSP 230605 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 205 AM EDT Thu May 23 2024 .SYNOPSIS... Temperatures will remain several degrees above normal each day through Tuesday of next week as humid subtropical air remains over the Southeast. Chances for showers and thunderstorms increase Thursday and will remain higher than normal for this time of year into next week as well. && .NEAR TERM /THROUGH TODAY/... As of 200 AM EDT Thursday: Areas of thicker high clouds seems to be delaying any fog development, as expected. The forecast area is expected to remain dry thru daybreak, as ripples of weak synoptic forcing will move overhead during the predawn hours, but will encounter air too dry to support much, if any, precipitation. The increasing cloud cover should help to inhibit fog formation, including the mtn valleys, thru daybreak, while keeping lows in the mid-60s, which is about 4 to 6 degrees above climatology. Otherwise, we can expect more convective activity for Thursday aftn/ evening. Despite the fact that flat upper ridging will remain to our south thru the near-term period, heights will fall on Thursday as a cold front sags into the upper Tennessee Valley/Cumberland Plateau. Afternoon profiles look much more favorable for convection with an influx of colder air aloft helping to increase lapse rates. This in turn should allow for the development of roughly 1000 t0 1500 J/kg of sbCAPE across much of our area and possibly more over the I-77 corridor. Shear values should remain fairly weak (ie, <30 kts of deep-layer shear) and low-level helicity will be minimal at best as well. Thus, strong to severe downburst winds appear to be the main threat for tomorrow with hail being more of a secondary threat. Thus, SPC`s current day 2 Marginal Severe Risk highlighting both wind and hail still appears pretty well placed. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... As of 215 PM Wed: A series of short waves will cross the area with some sort of weak surface feature associated with the waves. This will lead to mainly diurnal convection each day, with some lingering showers possible during the overnight periods. Moderate instability and bulk shear around 40 kts is possible on Friday, along with decent sfc delta Theta-e values. A few severe storms will be possible with some organization. With the good forcing in place, expect widespread to numerous convective coverage of the mountains and foothills and high end scattered coverage elsewhere. Temps will be around 5 degrees above normal. Coverage will not be as widespread on Saturday, but high end moderate instability, along with 20 kts of shear and continued high levels of sfc delta Theta-e values, along with increasing dCAPE may lead to an uptick in severe thunderstorm chances. These would be more of the pulse severe, damaging wind variety. Temps will be around 10 degrees above normal. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 230 PM Wed: Unsettled weather expected into early next week as the series of short waves continue to march across the area. Again, there looks to be weak surface features until Monday when a more organized cold front crosses the area. Expect precip chances to steadily increase Sunday and Monday, although the convection should be mainly diurnal. Some severe storms will be possible again especially if the moderate instability and shear and dCAPE overlap. Temps will be 5 to 10 degrees above normal. Some lingering showers possible Tuesday even as the front moves east, but thunder chances diminish. Temps will be up to 5 degrees above normal. Dry high pressure expected on Wednesday with temps near to slightly above normal. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: Thunderstorm chances return to the area today, as a cold front approaches from the NW. Plenty of high clouds are expected to stream in from the west thru the morning, which will limit fog potential. So expecting VFR to start the day. Convection is expected to fire across the NC mountains early in the aftn then spread/expand in coverage east late aftn thru the evening. There is a lot of disagreement among the CAMs on the timing of the convective initiation and tracking east. The latest PROB30 groups for TS are based on the HRRR, which has some run-to-run consistency, but confidence on the timing is below average. Convection will exit to the east late evening thru the overnight, leaving some debris mid and high clouds around, but some clearing is expected before daybreak. With expected scattered to numerous precip coverage, light winds and some clearing, may see areas of fog develop late tonight, especially in the mountain valleys and the NC Piedmont. Coverage of precip and subsequent fog potential is expected to be lowest across the Upstate. Outlook: Scattered to numerous showers and thunderstorms, along with their associated flight restrictions, are expected again on Friday. A more active pattern may persist thru early next week. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...ARK/JPT SHORT TERM...RWH LONG TERM...RWH AVIATION...ARK