textproduct: Columbia

WHAT HAS CHANGED

Thunderstorms developing this afternoon, favoring the southeastern portion of the area. Aviation discussion updated for 18Z TAF.

KEY MESSAGES

- 1. Daily shower and thunderstorm chances continue into the upcoming week, with localized flash flooding possible through Tuesday.

DISCUSSION

Key Message 1: Daily shower and thunderstorm chances continue into the upcoming week, with localized flash flooding possible through Tuesday.

Today/Tonight: Showers and thunderstorms have developed early this afternoon near the I-95 corridor and hires models do indicate the activity will gradually advance farther inland, although much of the heaviest rain is expected to fall in areas that have not received significant amounts in the past two days, limiting the overall flash flood threat. PWATs remain high, between 1.8 to 2 inches, well above average and forecast soundings indicate efficient rainfall which could lead to localized flash flooding, especially in training storms. Overall, the severe threat appears lower than yesterday with the wedge front shifted a bit southward, limiting surface based instability, although once again isolated strong precip-loaded downdrafts could lead to a damaging wind gust or two. A weak shortwave will likely spark additional convection across central Georgia later this afternoon into evening which will continue to move eastward. Latest CAMs have this activity weakening as it approaches our area tonight, likely due to the shortwave lifting to the north and west and a loss of daytime heating. Still it will be worth monitoring, especially for areas of northern Lexington and Richland counties where significant rain fell last evening and flash flood guidance indicates 1-2" per hour rates could lead to flash flooding.

Southwest flow will persist at least through the first half of the week with the synoptic pattern favoring ridging offshore and an upper low over east Texas. NAEFS mean indicates PWATs remain around or above the 99th percentile through Tuesday. Heavy rain and isolated flash flooding will be possible with afternoon convection, although a strong trough strengthening in the Pacific Northwest leads to strengthening ridging over our area which would limit forcing somewhat. With moisture so high and moderate destabilization each afternoon, will likely get scattered to widespread storms developing, favoring the sea breeze and propagating inland. Storm coverage Wednesday through the end of the week may be a bit more limited as southwest flow weakens but isolated diurnal showers and storms will remain possible.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Restrictions from showers/storms possible this afternoon and evening before more stratus is possible overnight into Monday morning.

Skies are gradually becoming VFR with cloud bases lifting this afternoon and winds picking up near 4-7 kts out of the southeast generally. An area of convection is currently moving near OGB, and activity is expected to continue near here over the coming hours as the inland pushing sea breeze is expected to bring more storms near here. The other TAF sites are a bit tricky as model guidance has trended towards keeping this initial activity away until after 21-22z as another round of showers/storms gets going, but the possibility remains outflow boundaries develop additional storms near the other TAF sites. The main restrictions with convection are expected to come from heavy rain (lower vsby's), though some gusty winds could be possible in the strongest storms. This evening a broken line of showers/storms is expected to approach the CSRA, bringing more possible restrictions from convection near AGS/DNL/AIK mainly from 22z through around 02z. This activity may reach the Columbia terminals as well. Showers may linger into the overnight before gradually diminishing into Monday morning. There is fairly good consensus another round of stratus and possibly patchy fog should develop late tonight, with MVFR to IFR ceilings expected after 05-08z, continuing into Monday morning. Winds likely remain light and out of the southeast overnight before becoming a bit more southerly after daybreak Monday through the end of the TAF period.

EXTENDED AVIATION OUTLOOK...Abundant low level moisture will bring more rounds of morning restrictions from fog and/low low clouds to start the next work week. Scattered afternoon showers and thunderstorms are possible each day into the middle of the week.

CAE WATCHES/WARNINGS/ADVISORIES

SC...None. GA...None.