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
911 FXUS62 KCAE 221747 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 147 PM EDT Sun Sep 22 2024 .SYNOPSIS... High pressure building over the SE US will keep warm conditions over the Southeast into the first half of the work week. Multiple shortwaves moving overhead bring at least daily slight chances for precipitation through much of the week. Confidence is low in the forecast beyond midweek as uncertainty remains high with the evolution of an upper trough moving toward the region and the potential for tropical development in the Gulf. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Upper ridge persists with above normal temperatures. - Isolated afternoon showers or storms over southeastern Midlands and CSRA. This afternoon: Hot temperatures persist underneath the upper ridge axis, with highs still on track to reach the low to middle 90s. Tonight: Weak surface trough may be able to trigger an isolated shower or storm across the eastern Midlands and CSRA early this evening, generally in an area with slightly higher pwat values. Any activity that develops would dissipate by 02z tonight, with dry conditions then expected the remainder of the night. Winds turning light overnight. Lows tonight remaining on the milder side, bottoming out generally around 70 degrees. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Key Message(s): - Upper ridge continues to bring above average temps. - Afternoon and evening precipitation is possible each day, mainly north. Upper ridging is expected to be over the area as surface high pressure is filtered into the region from the Northeast to start the short term period. Meanwhile, an upper trough is forecast to continue developing over the Upper Midwest. All of these features slide eastward over the short term period. Multiple shortwaves are forecast to ride around the periphery of the ridge as it passes overhead, bringing chances for precipitation to the northern half of the forecast area each afternoon and evening. Also, the upper trough is anticipated to dig southward and assist in developing a surface frontal boundary, resulting in southwest flow locally. The southwest flow will likely lead to increased moisture to the region ahead of the frontal boundary, bringing slightly higher chances for precipitation on Tuesday. Due to the ridging, temperatures are expected to remain on the warm side, with highs in the mid 80s north to lower 90s south each day. Overnight lows remain warm as well, with lows around 70. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Key Message(s): - Chances for precipitation increase in the long term despite forecast uncertainty. Uncertainty remains pretty high in the long term, leading to a lower confidence forecast. The two main features causing uncertainty are the aforementioned upper trough and the potential for tropical development in the Gulf of Mexico. For the trough, some guidance shows the trough will continue to most eastward as an open trough, while others indicate it will close off. For the tropical development, the National Hurricane Center is not expecting development in the next 48 hours, but has increased the probability of development to 70% within the next 7 days. So, confidence is increasing the some tropical system will develop in the Gulf, but where it goes and how strong it gets is where the uncertainty comes in. Assuming something does form, the strength and track of it will be partly dependent on what happens with the upper trough. Regardless of what happens, daily chances for precipitation continue through the forecast period. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Outside of KAGS, generally VFR conditions anticipated through the TAF period. KAGS may see usual mvfr/ifr visibilities overnight near the river. Skies mostly sunny this afternoon with satellite and visual observations showing the development of a few afternoon cu. Weak surface trough moving through the area, may combine with slightly better moisture and instability across the eastern Midlands and Central CSRA areas to develop an isolated shower during our peak heating hours this afternoon. Coverage would appear to remain rather limited based on latest models, and am inclined to keep mention of any activity out of any tafs due to the low confidence of a terminal being impacted. Conditions will remain vfr through the period at all taf locations except at KAGS. In that locations, the usual overnight development of mvfr/ifr visibilities will remain possible after 07z lasting through around 12z. Otherwise vfr at that location. Winds mostly out of the westerly around 5 to 6 knots through the afternoon, then light and variable overnight into Monday. EXTENDED AVIATION OUTLOOK...There are no significant concerns for restrictions at this time. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$