Sunrise 6:36 AM   Sunset 8:07 PM Moonrise 12:00 AM   Moonset 8:40 AM

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FXUS62 KCAE 281712 AFDCAE

Area Forecast Discussion National Weather Service Columbia SC 112 PM EDT Sun Apr 28 2024

SYNOPSIS
Weak high pressure centered northeast of the region will remain in control through Monday along with a warming trend. A weak front is expected to bring a slight chance of showers and thunderstorms late Tuesday through Thursday, mainly northern and eastern areas.

NEAR TERM /THROUGH TONIGHT/
SE flow continues today advecting moisture into the forecast area. However the moisture will be shallow with PWAT values around 1.2 inches from the GOES-16 derived imagery. The onshore flow should promote mostly cloudy skies but a considerable inversion aloft, along with some dry air, should prevent rainfall. The subsidence inversion is lower today than is was yesterday based on the 12Z CHS sounding. Yesterday the inversion began at about 700mb versus today's is lower at about 850mb.
This should prevent the shallow showers from developing that we saw yesterday. This evening low clouds will begin to diminish with sunset with mid and high clouds also clearing tonight. This could allow low stratus or fog to develop early Monday morning.
High temperatures this afternoon will be in the upper 70s to low 80s with lows tonight in the mid 50s.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
Quiet weather is expected to continue on Monday, with high confidence in the forecast. Latest ensemble and operation guidance continues to show our pattern moderating downstream from the active central Plains. A series of shortwaves and low pressure systems are forecast to ride northeastward atop the ridge over the eastern US, with fronts slowly pushing the low-level ridge axis southward. In turn, our prevailing flow will shift from southeasterly to southwesterly on Monday. As a result, warm air advection is likely to be a bit more notable, with 850 hPa temps starting the day in the 12-14C range. This will allow highs to likely jump into the low and mid 80s, with more sunshine aiding the warming trend. Rain is unlikely as we'll see subsidence under shortwave ridging, manifested in a strong inversion showing up in model soundings between 750-800 hPa. Overnight, look for dry conditions to continue, with lows in the upper 50s and lower 60s.

A slow moving shortwave trough is forecast to approach the forecast area on Tuesday. Guidance has slowly trended towards a more organized trough and a slower progression of said trough on Tuesday.
As a result, there is more forcing aloft for precipitation Tuesday afternoon. Big however, though. Guidance is split on the amount of moisture that will be in place ahead of this as the front and upper level support approaches Tues afternoon/evening. Amongst LREF guidance, GFS/GEFS are the most aggressive with rainfall chances, while the ECM/ECE members are least aggressive. The Canadian ens & operational model (and the early runs of the NAM) are somewhere in the middle, which seems like a reasonable spot to be in currently.
The fly in the ointment is how much mixing we see by Tuesday afternoon, which could lower our dewpoints and yield lesser instability. I think the middle of the road is a good scenario here, with scattered showers or thunderstorms developing by the afternoon hours. Guidance (other than the ECM) is suggesting at least ~500 j/kg of CAPE developing for much of the area, which should yield the chance of thunderstorms. With weak shear, though, anything severe is unlikely. Highs will likely be in the mid to upper 80s across the area. Some showers could continue into Tuesday night, with lows in the low 60s.

LONG TERM /WEDNESDAY THROUGH SUNDAY/
Confidence in the long term remains fairly high. Front should slowly push through the area on Wednesday, with all LREF members showing afternoon/evening rain chances persisting as the front won't totally clear the region and moisture will remain in place ahead of it. Mid- level ridging will again build in by late week, with temperatures warming to near 90 Thur/Fri with subsidence aloft keeping us dry and sunny. By Saturday and Sunday, ensembles and operational models begin to show a more active pattern developing, with showers and thunderstorms possible again. So in general, the short and long term periods are fairly high confidence, especially with regards to above normal temperatures developing. Confidence is also high that our best chances of rain/storms will be Tues/Wed, & Sat/Sun.

AVIATION /18Z SUNDAY THROUGH FRIDAY/
Stratus and fog possible early Monday morning.

A subsidence inversion aloft will hinder vertical growth and prevent showers at the terminals today. Clouds will diminish with sunset as some drier air moves into the area. Clearing tonight and light winds could promote fog and stratus development early Monday morning. The highest confidence is in AGS experiencing its typical river-valley-based fog but all sites could see restrictions from 09Z to 15Z Monday. After 15Z winds will pick up out of the south with a few cumulus and high clouds.

EXTENDED AVIATION OUTLOOK...Restrictions possible in early morning fog or stratus. Then there is at least a slight chance of afternoon showers and thunderstorms Tuesday onward.

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

Bacon Bridge
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Sun -- 12:03 AM EDT     Moonrise
Sun -- 01:55 AM EDT     2.12 feet High Tide
Sun -- 06:35 AM EDT     Sunrise
Sun -- 09:31 AM EDT     0.23 feet Low Tide
Sun -- 09:39 AM EDT     Moonset
Sun -- 02:07 PM EDT     1.65 feet High Tide
Sun -- 08:00 PM EDT     Sunset
Sun -- 09:18 PM EDT     0.19 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Bacon Bridge, Ashley River, South Carolina, Tide feet

Cuckolds Creek
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Sun -- 12:04 AM EDT     Moonrise
Sun -- 04:01 AM EDT     3.74 feet High Tide
Sun -- 06:38 AM EDT     Sunrise
Sun -- 09:42 AM EDT     Moonset
Sun -- 10:12 AM EDT     1.04 feet Low Tide
Sun -- 04:29 PM EDT     3.11 feet High Tide
Sun -- 08:02 PM EDT     Sunset
Sun -- 10:05 PM EDT     1.03 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Cuckolds Creek, Combahee River, South Carolina, Tide feet

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Columbia, SC,