Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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718 FXUS62 KCAE 012237 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 637 PM EDT Wed May 1 2024 .SYNOPSIS... Dry and warm conditions will continue through Thursday as surface high pressure and upper level ridging build back into the area. Rain chances start to increase Friday as southwesterly low level flow increases and steadily pushes moisture into the region. Showers and thunderstorms are then likely over the weekend as a series of weak disturbances push across the area and moisture continues to build. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Line of cu associated with coastal sea breeze can be seen clearly on vis satellite moving inland. This has been enough to set off a few isolated thunderstorms near the coast where there is deeper moisture and still a touch of cyclonic flow aloft. However, dry mid to upper levels is there to great the boundary as it moves into the southeasternmost midlands and CSRA, so it will be difficult to see much in the way of shower activity this evening in the CWA. Since there is low level moisture in the southeastern half of the CWA, and winds are expected to be light all night, I think some fog is in the offing once we get past midnight. I have introduced patchy fog for many areas in the forecast for late tonight and early Thursday morning, with areas of fog in the southeast where the moisture will be a bit deeper on the oceanward side of the decaying sea breeze. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... Thursday and Thursday night: Quiet and dry conditions are expected for Thursday and Thursday night as ridging aloft builds and surface high pressure builds just offshore. As a result, afternoon highs will likely be a few degrees warmer than Wednesday, with temperatures reaching the mid to upper 80s. Seasonably mild overnight lows can also be expected as temperatures drop into the lower 60s. Friday and Friday night: The upper ridge begins to flatten while the axis shifts offshore. Meanwhile, a shortwave trough is forecast to move toward the area and PWAT levels increase during the day to over 1.5". This combination brings an increasing chance of afternoon showers and maybe thunderstorms, mainly for the western portions of the forecast area. CAPE values are forecast to be on the lower side (100-200 J/kg) and shear values are forecast to be around 15 kts, so the severe weather threat is very low. Diurnal temperatures should be similar to Thursday as well. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A more active, summer-like pattern looks to be setting up for the weekend and into the first part of next week. The upper trough is forecast to begin weakening through the weekend with a series of shortwaves moving through the Southeast. These shortwaves bring the chance for daily (mainly) afternoon showers and thunderstorms into the early part of next week. Low-level flow is expected to become southwest, bringing additional moisture to the region. As a result, the risk for stronger storms increases for each afternoon as the instability gradually increases each day. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... VFR through early tonight. Slightly drier low level air in place today across much of the forecast area (FA), with lower dewpoints noted late this afternoon at DNL/AGS. SCT diurnal Cu is expected to dissipate this evening, leaving clear skies and very light winds overnight, with weak surface high pressure over the area. Some radiation fog, and possibly stratus, expected to develop late tonight. With very little wind, think fog and VSBYs will be more of an issue than CIGs. Guidance generally indicates best potential over southern and eastern areas, favoring OGB and the Coastal Plain, with IFR to LIFR potential. Think less potential at DNL/AGS with the drier low level air, though will indicate MVFR VSBYs at AGS due to the localized fog prone nature of the site. After early morning restrictions dissipate, expect VFR conditions Thursday with a relatively dry atmosphere and an upper ridge overhead. Diurnal Cu expected, with any bases above VFR level. EXTENDED AVIATION OUTLOOK...Late night/early morning fog and stratus possible through the period. Increased potential for showers and thunderstorms Friday afternoon through Monday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$