Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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428 FXUS62 KCAE 020539 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 139 AM EDT Tue Jul 2 2024 .SYNOPSIS... A cold front will move south of the area this afternoon and tonight. Slightly cooler and drier air will spread into the area through Tuesday. Moisture will slowly increase across the area mid to late week. High pressure building aloft by mid to late week will result in well above normal temperatures by the weekend. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... KEY MESSAGES: - Cooler behind a front tonight with isolated showers in the southern area. Surface analysis indicates that the cold front is just south of the forecast area with drier air pushing in from the northeast. Some isolated shower activity remains possibly near the front but otherwise drier and cooler tonight with lows in the mid-60s in the north to low 70s south. && .SHORT TERM /7 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... KEY MESSAGES: - A brief respite from the heat and humidity. Tuesday and Tuesday night...The upper trough will be off the New England and Mid Atlantic coast with an upper ridge to our west across the lower Mississippi Valley. The front appears to move south of the area and drier and cooler air will advect south from North Carolina. Precipitable water decreases to less than an inch in the northern Midlands to near 1.5 inches south. RH values 35% north to near 60% south. The Nam model is much cooler than other guidance mainly due to considerable low cloudiness. Think these clouds are a little overdone, but clouds may linger in the southern areas until drier air spreads south in the afternoon. So went with a consensus incorporating the NBM 25th percentile temps. This gives me mid 80s across the region. The air mass appears mainly stable in the afternoon and think at most, an isolated shower is possible in the southeast Midlands and CSRA. But cut pops from previous forecast and overall NBM pop guidance. Overnight temps near or slightly below normal, 65 to 70 degrees. Wednesday and Wednesday night...The upper ridge will be building east across the area and expect subsidence to increase. Moisture appears tor remain quite low across the region although late in the day, precipitable water increases in the Piedmont around 850mb ridge. Air mass appears stable. So, expect temperatures to warm a bit to near normal values and any showers should be quite limited. Lowered the pops to mainly less than 15 percent, i.e., below the NBM mean pop. && .LONG TERM /THURSDAY THROUGH MONDAY/... KEY MESSAGES: - Heat and humidity returns back to the region as high pressure aloft rebuilds once again. The upper ridge builds across the area and precipitable water increases again to near or above 2 inches, especially by the weekend. High confidence we will be at least reaching heat advisory criteria by Saturday and possibly excessive heat conditions as max temps reach 100 degrees or a little higher. As moisture increases late week and the Piedmont trough sets up to provide some low level convergence, expect an unstable air mass leading to scattered mainly diurnally driven thunderstorms. The upper ridge shifts to the coast over the weekend as a series of low amplitude trough move from the northern Plains across the Great Lakes/Upper Mississippi Valley. This will push a weak front toward the area, possibly moving into the area Monday. Ensembles are showing precipitable water > 2 inches by Sunday as moisture flux increases ahead of the frontal system. Chance of afternoon and evening thunderstorms possibly increasing a bit as the front approaches. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... VFR conditions likely at all TAF locations through the period, with some low end MVFR cigs possible at OGB/AGS/DNL over the next few hours. Dry air has filtered into the forecast area, with most of the clouds hanging off to the south of the TAF sites. Some MVFR ceilings are trying to work their way into the southern sites, and thinking is that OGB has the best shot at consistently seeing ceilings between 2500 and 3000 feet for the next few hours. AGS and DNL certainly may see some restrictions, but it isn`t as likely so a TEMPO group will cover the possibility there. Beautiful weather is expected after this diminishes, as the dry air will remain in place through much of the period. Clouds will be few to scattered, and winds should slowly veer from easterly or northeasterly to southeasterly by the end of the period. EXTENDED AVIATION OUTLOOK...No restrictions expected through midweek outside of some early morning stratus which may briefly become MVFR. Moisture returns late in the week with afternoon showers and thunderstorms possible into the weekend. && .FIRE WEATHER... KEY MESSAGE(S): -Increased Fire Danger mid to late week. -Rainfall probabilities remain relatively low mid week. Increased fire danger during the Independence Day Holiday week, especially late week as temperatures rise again to well above normal values. Scattered afternoon and evening thunderstorms possible may aid current dry conditions. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION... FIRE WEATHER...