textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated and a new key message for the potential for patchy dense fog was added.

KEY MESSAGES

- 1) Below normal rain chances through Friday with increasing rain chances over the weekend.

- 2) Patchy to areas of fog will be possible tonight with some dense fog possible.

- 3) Hot and humid conditions expected into the upcoming weekend.

DISCUSSION

KEY MESSAGE 1: Below normal rain chances through Friday with increasing rain chances over the weekend.

Wednesday: Mostly dry conditions will prevail through Wednesday as the broad upper ridging builds over the area. Based off 12z sounding data, the subsidence inversion has not quite built over the area but it has show up over interior part of south Carolina and Georgia. However, the profile even today remains rather dry and should continue to dry out as subsidence builds eastward. As a result, there should not be much in the way of clouds let along rain tomorrow.

Thursday through Labor Day: High pressure should become centered over the Carolinas by the end of the week. This will keep a fairly hot, dry and subsident environment in place with a progressive resultant sea breeze likely to occur each afternoon. There may be just enough moisture return along southwest flanks of the surface high pressure centered well offshore to allow for isolated to perhaps scattered showers/tstms to develop by Thursday and Friday across southeastern Georgia. However, much will depend on exactly where the center of the upper high becomes situated. Rain chances will increase over the Labor Day holiday weekend as the upper ridge breaks down in response to broad troughing developing across the eastern CONUS. This system should push a cold front into the area and possibly drops southward through the Southeast States with shower and storms focused along this advancing boundary.

KEY MESSAGE 2: Patchy to areas of fog will be possible tonight with some dense fog possible.

With the high pressure building over the area and enough low level moisture hanging around we should see another night of potential low stratus and fog to develop. Given the last few nights fog and some guidance supporting at least patchy fog developing mainly along and east of I-95 we went ahead and added patchy to areas of fog for the entire area tonight. Some locations could be dense; however, confidence in fog let alone dense fog is too low to support the need for a product at this time. If confidence for dense fog increases this evening, then a special weather statement or advisory may be needed.

KEY MESSAGE 3: Hot and humid conditions expected into the upcoming weekend.

Aloft, a ridge of high pressure will extend from the Midwest to the Mid-Atlantic/Southeast regions today, marking the beginning of a warming trend mid to late week. Today, the region will start to slide under the eastern periphery of the ridge, bringing widespread temperatures in the upper 80s to lower 90s, with heat index values in the upper 90s to lower 100s. On Wednesday, the ridge axis remains slightly north of the local area while weak h5 vort energy shifts onshore across the Southeast Coast late Wednesday and Thursday, which should maintain similar heat/humidity conditions with slightly higher chances of precip and clouds across southern areas mid-week. Heading into late week, a notable increase in ridging occurs aloft, supporting warmer temps into the low-mid 90s Friday, then mid 90s Saturday. These temps in combination with mid-upper 70 dewpts could support Heat Advisory conditions across the coastal corridor this weekend (highest chance Saturday), before a cold front arrives early next week.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

01/18z TAFs: KCHS/KJZI/KSAV: VFR will prevail for all terminals through 02/09z. Light easterly winds will becoming light and variable overnight with yet another round of low stratus and fog possible between 09Z and 14Z at all terminals. IFR to LIFR vsbys and cigs have been added to the TAF with this cycle and if confidence increases temporary reduction to VLIFR could be added with future updates. VFR conditions should return after 14z to the entire area.

Extended Aviation Outlook: Showers/thunderstorms could bring brief flight restrictions to the SAV terminal Thursday and Friday. Greater chances for flight restrictions with showers/thunderstorms arrive to all terminals Saturday with a passing cold front.

MARINE

Through Tonight: There are no concerns. Northeast winds will back more easterly at the coast this afternoon as the sea breeze forms and moves inland. East winds this evening will gradually back to the northeast again near the beaches late. Winds look to remain 10 kt or less through the period with seas 3 ft or less. Some patchy marine fog could be possible after midnight, especially across the immediate nearshore coastal waters and Charleston Harbor.

Wednesday through Sunday: High pressure north/offshore and weak coastal troughing positioned closer the Southeast Coast will support conditions well below Small Craft Advisory levels through mid week, although increasing chances for thunderstorms should occur across Georgia waters on Thursday. Outside this activity, onshore flow should peak between 10-15 kt daily with afternoon sea breeze circulations while seas range between 2-4 ft. Conditions should remain below Small Craft Advisory levels this weekend, but there should be a slight uptick in winds (15-20 kt) as a cold front approaches, then shifts across local waters. Seas remain between 1-3 ft during this timeframe.

Rip Currents: A modest east-northeast wind along with long period swells of 2.5 ft every 12 seconds supports a Moderate Risk of rip currents along Georgia beaches Wednesday.

CHS WATCHES/WARNINGS/ADVISORIES

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