Sunrise 6:19 AM   Sunset 8:22 PM Moonrise 2:04 PM   Moonset 2:17 AM

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FXUS62 KCAE 180107 AFDCAE

Area Forecast Discussion National Weather Service Columbia SC 907 PM EDT Fri May 17 2024

SYNOPSIS
Chances of showers and thunderstorms will continue overnight as a weak system begins to slowly cross the region. 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 /UNTIL 7 AM SATURDAY MORNING/
Positively tilted upper trough continues to slowly progress through over the central/southern Plains toward the Mississippi River Valley this evening. Southwest flow aloft continues to usher in moisture with PWATs between 1.5" and 1.7" and dewpoints in the mid to upper 60s. PW values are expected to increase overnight to between 1.7" and 1.9", with a few locations closer to 2" across the CSRA/southern or eastern Midlands.

Ongoing convection to our south is progged to remain out of the area tonight. However, weak short wave energy moving through the mid level flow is expected to generate scattered showers across the area amid increasing isentropic lift. The latest HRRR shows a reasonable solution, with perhaps a bit of a stronger area of showers and thunderstorms pushing through the CSRA around daybreak. Severe threat remains low though brief heavy rainfall is possible.

Overcast skies and a well-mixed boundary layer keep overnight lows quite mild, only falling into the mid to upper 60s/near 70. Low dewpoint depressions may generate some reduced visibilities in and near shower activity.

SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/
Positively tilted trough will continue to slowly push eastward towards us and should be centered across the lower MS Valley by tomorrow morning. Strong flow at 500 hPa is expected to create strong shear profiles, and CAMs are generally showing some sort of MCS structure to our southwest, but how far north this gets and how fast it will be is in question. Generally, guidance has struggled with speed and placement of convective structures like this in recent weeks. So there is uncertainty about this, but confidence is high that an MCS of some sort will be in central GA at the start of this period. Ahead of this, rich moisture should favor some instability, and given the shear in the atmosphere, strong to marginally severe storms are again possible depending on the location of this convection. Thinking the best chance for this is in the southern FA, but timing and severity is hard to piece together right now. Think it'll be approaching or through our FA by late morning, and if this happens, it opens the door for some afternoon sunshine and another round of thunderstorms in the central and northern FA.
While the strongest shear will be to our east, robust instability is possible where we see sunshine tomorrow afternoon so we'll need to watch for strong strong storms along an amorphous surface front across the northern part of SC. Highs should generally be in the mid 80s but upper 80s are possible for those that see more sunshine. Showers will probably hang around into Saturday night as the trough approaches with lows in the mid 60s expected. On Sunday, more showers and embedded thunderstorms are possible as the trough approaches and pushes over the region. Some uncertainty is present with where the surface low and resultant convergence develops, adding some overall uncertainty to rain coverage Sunday afternoon. But confidence is high that we'll see scattered to numerous showers across much of the area, with highs in the upper 70s and low 80s. Showers should clear out on Sunday night as a back door front pushes through and pushes low PW air into the area.

LONG TERM /MONDAY THROUGH FRIDAY/
Confidence continues to remain fairly high in the long term period. Cool and dry air is expected to remain in place on Monday, with highs well below normal near 80s. Modification quickly begins on Tuesday as high pressure shifts to our east and ridging aloft begins to build. This should carry highs back into the upper 80s and low 90s by Thursday. Another cold front is forecast to approach by the Thur/Fri timeframe, with the possibility of showers and thunderstorms in the afternoon in association with that.

AVIATION /01Z SATURDAY THROUGH WEDNESDAY/
Restrictions to begin overnight and continue into Saturday.

A few showers earlier this evening have moved out of the region, leaving behind VFR ceilings for the time being. After sunset, ceilings are expected to lower to eventual IFR levels after about 07z. Guidance is not as consistent at AGS/DNL for IFR, so addressed that with a TEMPO group. Low level moisture will also likely lead to areas of fog overnight with scattered showers possible. Latest guidance has been indicating less shower coverage overnight than earlier runs, but with the low level moisture in place, showers can't be ruled out. Ceilings begin to improve after 15z or 16z, and anticipated to return to VFR after around 21z.Another round of showers and potential thunderstorms arrives late in the period.

EXTENDED AVIATION OUTLOOK...Increased confidence in restrictions with showers and thunderstorms continues through Sunday night.

CAE WATCHES/WARNINGS/ADVISORIES
SC...None.
GA...None.

Bacon Bridge
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Fri -- 01:31 AM EDT     0.42 feet Low Tide
Fri -- 03:12 AM EDT     Moonset
Fri -- 06:19 AM EDT     Sunrise
Fri -- 06:39 AM EDT     1.76 feet High Tide
Fri -- 02:01 PM EDT     0.31 feet Low Tide
Fri -- 03:00 PM EDT     Moonrise
Fri -- 07:24 PM EDT     1.77 feet High Tide
Fri -- 08:15 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION

Bacon Bridge, Ashley River, South Carolina, Tide feet

Pimlico
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Fri -- 01:47 AM EDT     1.08 feet Low Tide
Fri -- 03:12 AM EDT     Moonset
Fri -- 06:18 AM EDT     Sunrise
Fri -- 07:22 AM EDT     1.62 feet High Tide
Fri -- 02:17 PM EDT     0.80 feet Low Tide
Fri -- 02:58 PM EDT     Moonrise
Fri -- 08:07 PM EDT     1.63 feet High Tide
Fri -- 08:14 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION

Pimlico, West Branch, Cooper River, South Carolina, Tide feet

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Columbia, SC,