Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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896 FXUS62 KCAE 081828 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 228 PM EDT Sat Jun 8 2024 .SYNOPSIS... Dry conditions continue through tonight with the potential for afternoon/evening showers and thunderstorms on Sunday as a cold front approaches. The front moves through the area and stalls along the coast early next week. This will result in scattered showers and a few thunderstorms at times through mid-week. Moisture may increase across the area mid to late week as a low pressure system develops in the Gulf of Mexico. This may lead to an increase in showers and thunderstorms. Temperatures will be near or above normal early in the week but cooler temperatures possible late in the week. && .NEAR TERM /THROUGH TONIGHT/... The flow aloft continues to be out of the northwest this afternoon as the forecast area is positioned between an upper ridge along the gulf coast and an upper trough centered north of the Great Lakes. Guidance continues to show the passage of a shortwave this evening but this should only result in an increase in mid to high level cloudiness as currently clear skies become mostly clear to partly cloudy. The clouds should arrive too late to have a significant role in high temperatures which are on track to reach the upper 80s to lower 90s. The increase in cloudiness will likely limit nocturnal cooling. The clouds combined with surface winds shifting to the southwest towards daybreak suggest overnight temperatures will be a few degrees warmer than last night with lows generally in the mid- 60s. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Sunday and Sunday night...Anomalously deep upper low over southeastern Canada/New England with west-north-westerly flow across the Carolinas into Georgia. A cold front will be extending from the Mid Atlantic region southwest across Tennessee by late in the day or evening. Weak Piedmont/pre frontal trough across SC. With west-northwesterly flow across the area ahead of the front, expect downslope and resulting adiabatic warming. So, temperatures are expected to rise into the mid 90s. But there are a couple of issues...1) Moisture appears to increase through the day with precipitable water likely increasing to greater than 1.5 inches based on ensembles. Satellite showing considerable upstream cloudiness associated with decaying mesoscale system over Kentucky. Additional clouds associated with short wave troughs in northwest flow. So expect some cloudiness especially in the afternoon 2) A few scattered showers/thunderstorms may develop in the afternoon, after 18z as weak short waves move southeast through the area with strongest dynamics across the north Midlands to the Pee Dee. The CAMS and model MOS/NBM suggest the highest pops across the north. But can`t rule out a few showers and thunderstorms developing in the rest of the area primarily in the evening as the cold front drops southeast into and probably through the area during the overnight. Some of the CAMS suggest more coverage near and south of CAE. SPC now has the area in a marginal risk, with models indicating strong deep layer shear, 30-40kt 0-6km. Instability weak to possibly moderate. So raised pops above NBM guidance all areas mainly during the evening. With increase in moisture, overnight lows expected to be a little above normal, the drier air behind the front is likely delayed until after daybreak Monday. Monday and Monday night... The ensembles are indicating the upper low over New England will be amplifying and moving south toward the Mid Atlantic and Carolinas. A few short waves will rotate through the base of the trough but the stronger dynamics should stay mainly to the north across North Carolina. The deterministic models suggest the front will be south of the area. The ensemble suggest some uncertainty as to where the front will be. So, kept low chance pops in the southeast Midlands/CSRA closer to the front. Dry air filtering in from the north so very low pops to the north but can`t rule out a showers with additional short wave troughs moving through the base of the longwave trough. Moisture should be limited though especially north of CAE. Slightly cooler behind the front with some lingering clouds. Highs near the NBM, mainly in the 80s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Uncertainty remains in the extended period. Drying expected now Tuesday as the upper low opens up and moves off the coast. Short wave ridging expected across the area. The front may be diffuse near the area so with some uncertainty, can`t rule out a few isolated showers southeast Midlands. But model trend is drier. Another upper low will move toward the Deep South from the southern Plains and may cut off over the Gulf of Mexico. the ensemble guidance suggests uncertainty mid to late week as this low possibly develops. Expect at least an increase in some moisture across the region especially late week into next weekend. The models differ on any surface low development and placement but overall the upper low is expected to retrograde to the western Gulf late in the period. Temperatures may be cooler but the NBM is near normal values. Uncertainty with pops but the NBM has generally scattered showers through the extended period, more likely diurnally driven at this point. && .AVIATION /18Z SATURDAY THROUGH WEDNESDAY/... VFR Conditions Likely to Persist through the TAF Period.... Clear skies and generally light northerly winds are being observed at the terminals this afternoon as high pressure builds in from the west. A vast area of cloudiness currently in the Ohio and Tennessee valleys will move in from the northwest bringing increasing mid to high level cloudiness for the evening and overnight hours. Surface winds should shift towards the southwest by daybreak Sunday resulting in an increase in moisture but the terminals should remain dry through the end of the current TAF period with no restrictions expected. EXTENDED AVIATION OUTLOOK... Increasing moisture could produce early morning low stratus and/or fog in addition to afternoon/evening showers and thunderstorms, potentially causing in brief restrictions at the terminals. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$