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
36
37
38
39
40
41
42
43
44
45
316 FXUS62 KCAE 301843 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 243 PM EDT Tue Apr 30 2024 .SYNOPSIS... A shortwave trough aloft will push through the area Tuesday and bring scattered showers-storms in the afternoon and evening. Expect drier, warmer weather for Thursday and Friday with highs back in the mid to upper 80s. Shower and thunderstorm chances increase for the weekend as low level moisture increases. There will be at least a slight chance of showers and thunderstorms through the end of the long term with above normal temperatures favored. && .NEAR TERM /THROUGH TONIGHT/... A potent mid-level shortwave trough continues to move through the TN valley this afternoon. WAA ahead of this feature has increased temperatures into the upper 70s and low 80s with dewpoints in the low 60s due to onshore flow with the surface high sitting offshore. PWATs are generally between 1" and 1.3" with this highest values across the CSRA. This feature will translate through the state this afternoon into this evening with scattered showers and thunderstorms forming amid 500-1500 J/kg of SBCAPE. A quick look at a few other parameters reveals strong low-level lapse rates but modest mid-level lapse rates, and effective bulks shear of 25-35 kts. Therefore, any severe potential appears limited. The caveat to this is a thin corridor of 800-900 J/kg of DCAPE extending from the CLT area south to around SAV, likely due to some mid-level dry air intrusion. That in mind, storms that develop will have the potential for producing some gusty winds. CAMS suggest the bulk of the showers and thunderstorms should diminish by around 01/03z, with most of the CWA precip-free after about 01/06z. There should then be a period of clearing late tonight into early Wednesday morning, with guidance suggesting the development of some patchy fog/stratus. This should be focused west of Columbia into the Augusta area, since moisture will be slow to move out as winds diminish in the boundary layer. As such, another night of mild lows with values in the low 60s. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... An upper level ridge will build into the Southeast on Wednesday. Drier air will also move into the area from the west with PWAT values around 1 inch. Expect isolated to scattered showers along the coastal plain and into the eastern Midlands where low level moisture is higher. The severe weather threat is low given the dry air aloft hindering growth and warmer temps aloft. A downslope component to the wind fields will help push temps back above average, in the mid to upper 80s. As we move into Thursday, broad ridging will deepen across the SE CONUS and the ridge axis will set up nearly directly overhead. So while the dry northwest flow will weaken, general subsidence will continue and skies will remain mostly clear again Thursday. Thursday`s highs will be in the mid to upper 80s. As surface high pressure strengthens offshore, surface winds will turn more out of the east in the afternoon and allow dew points to push back into the 60`s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... The WPC cluster analysis page shows that most ensemble members keep broad ridging in place through the long term, however not as amplified as Thursday and Friday. This will open up the synoptic pattern to a series of weak shortwaves sliding to our northwest starting this weekend through the end of the period. Ensembles generally favor an increase in atmospheric moisture over the weekend with PWAT values around the 90th percentile. This pattern of shortwaves riding over broad ridging and above normal PWATs favor at least a chance of showers and thunderstorms each day of the long term with highest PoPs over the weekend when atmospheric moisture is expected to be highest. Thunderstorms in general will be favored during the afternoon hours but could fall outside the typical diurnal period if shortwave troughs cross the region outside of peak heating. Above average temperatures are likely through much of the long term. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... Generally VFR conditions this afternoon with occasional restrictions due to scattered showers and thunderstorms. SCT-BKN cumulus with high clouds. CIGs generally remaining VFR, but with the development of -SHRA/-TSRA, occasional MVFR/IFR restrictions. Scattered convection develops this afternoon and moves through the terminals into the evening. Patchy light showers possible until about 01/06z, then generally dry at the terminals. Patchy fog possible late tonight if skies clear enough toward daybreak. Outside of convection, winds around 10 kts into this evening from the south/southwest then speeds decreasing overnight. Winds Wednesday morning increasing out of the north/northwest generally remaining less than 8 kts. EXTENDED AVIATION OUTLOOK...Restrictions become possible Friday night into Saturday ahead of a frontal boundary. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$