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
278 FXUS62 KCAE 181430 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 1030 AM EDT Sat May 18 2024 .SYNOPSIS... Periods of showers and thunderstorms are expected today and into tonight. Rich moisture across the region will keep rain chances likely lingering into Sunday. Cooler and drier air moves in for Monday and Tuesday with temperatures rebounding during the middle of next week as another ridge moves in from the west. && .NEAR TERM /THROUGH TONIGHT/... An upper level low, part of a broader positively tilted upper level trough, is centered over eastern Arkansas and western Tennessee this morning. This upper trough, along with an associated weak surface low pressure system, will move east toward the area through tonight. Morning shower activity will continue shifting east and eventually out of the area by midday, leaving much of the early to mid afternoon rain-free as convection across the Florida Panhandle robs moisture advection into the area. Convection is expected to redevelop later in the afternoon as forcing ahead of the approaching upper trough increases across the area. The higher resolution mesoscale models generally show the greatest coverage of this convection across the northern Midlands and into the Pee Dee into this evening. The overall severe weather threat appears limited today, as morning shower activity and abundant cloud cover will limit instability. However, if storms do become strong or even severe, the greatest potential appears to be across the northern Midlands and Pee Dee where instability and forcing will likely be greatest. Strong wind gusts appear to be the primary threat, but there is some hail potential as well. Temperature rises will be limited by the abundant cloud cover today, but warm air advection with a southwesterly low level flow in place should allow for highs in the upper 70s to lower 80s. Any convection this evening should gradually wane as the best lift moves out. It will remain cloudy though with temperatures falling into the lower to mid 60s tonight. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Sunday and Sunday night...Highly positively tilted upper level trough will be just west of the forecast area at daybreak and gradually move eastward through the day reaching the coast by Sunday evening. At the surface a weak boundary will be sinking southward with winds turning northerly with passage and the atmosphere becoming increasingly stable indicating wedge-type conditions. The boundary will push into the northern Midlands and Pee Dee by daybreak through the central Midlands during the mid morning then begin weakening as it reaches the southern Midlands and CSRA by mid afternoon. Although much of the forecast area will see increasing stability there will be some instability in the far eastern Midlands into the southern CSRA which could generate a few thunderstorms if there are enough breaks in the clouds to allow for sufficient heating. Overall have lowered pops and increased clouds which has also resulted in afternoon high temperatures also coming down a few degrees with low 70s in the north and upper 70s to around 80 in the southern Midlands and CSRA. Sunday night the upper trough will continue slowly moving offshore with high pressure building in at the surface. Model soundings indicate plenty of dry air overtaking the region Sunday night however moisture will be trapped near the surface resulting in partly to mostly cloudy conditions overnight. With the continued northerly flow low temperatures Sunday night will be in the upper 50s to around 60. Monday and Monday night...Upper level ridging will be approaching the region Monday and Monday night as the upper level trough becomes nearly stationary over the western Atlantic. High pressure will control the surface with dry air dominating the mid and upper levels. Mid level lapse rates will be 5.5 C/Km at best so any cumulus which form will be vertically limited. Northerly flow will persist over the region so although there will be partly to mostly sunny skies allowing for plenty of sun expect afternoon highs in the upper 70s to low 80s. With little change for Monday night expect another night of partly cloudy skies and overnight lows in the upper 50s to around 60. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Upper level pattern remains amplified yet progressive through the long term. Upper level ridging and weak surface high pressure will remain in control of the area through Wednesday night with the next frontal boundary currently expected to move into the region Thursday. As it typical for this time of year the front will struggle to reach the forecast area and stall just to the northwest. This will result in the front acting more as a focusing mechanism for showers and thunderstorms Thursday and Friday with the highest pops over the northern Midlands. Temperatures through the long term will be near to slightly above normal. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... Periodic Restrictions Possible through the TAF Period... The morning shower activity has generally moved east of the terminals as of late morning, but flight restrictions persist at most terminals due to lingering low ceilings. Guidance suggests that ceilings should improve around midday with a return to VFR conditions in the afternoon. However, additional showers and thunderstorms will be possible across the region later this afternoon. The forecast will maintain VCSH after 21Z due to low confidence in thunderstorm timing. EXTENDED AVIATION OUTLOOK...Periodic restrictions from showers and thunderstorms continue through Sunday night. Low ceilings are also possible Sunday morning. Conditions should improve on Monday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$