textproduct: Charleston

WHAT HAS CHANGED

The aviation section has been updated for the 6Z TAFs. Added a Climate section for near record high temperatures on Friday. Introduced a key message for warm and unsettled conditions later this week.

KEY MESSAGES

- 1) A period of unsettled and warm conditions for the end of the week into the weekend.

DISCUSSION

KEY MESSAGE 1: A period of unsettled and warm conditions for the end of the week into the weekend.

A ridge of high pressure centered over the Gulf of America builds during the later half of the week, with warm and moist southwesterly surface flow setting up over the region. Temperatures throughout the atmospheric column consistently flirt with the 90th percentile wrt climatology, per the latest ensemble situational awareness tables, which will result in daily maximum surface temperatures in the mid 70s to lower 80s Thursday through Saturday. Overnight low temperatures will be similarly warm in the upper 50s to lower 60s, which will be closer to our normal daily highs for this time of year in the mid 60s compared to normal lows in the lower 40s. Not currently forecasting record temperatures, but that could change with future forecast updates.

Unsettled conditions will likely accompany the warm temperatures at times, as isentropic lift from positive theta-e advection should provide enough lift to spark off at least scattered showers. Isolated thunderstorms will also be possible when instability levels rise, and while model agreement is overall good, agreement isn't high enough to pinpoint what day thunderstorms are to be expected.

A cold front is expected to push through the region at some point on Sunday.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Prior to the 6Z TAFs, IR satellite indicated an expansive area of restrictive ceilings from the Foothills to the coast. TAFs will initialize with MVFR ceilings and light winds, showers have generally dissipated. Forecast soundings and MOS indicates that IFR ceilings are forecast to develop as cloud bases lower by 9Z this morning. Once IFR ceilings form, cloud bases may remain below 2 kft until early this afternoon. Gusty NNE winds should develop after daybreak, with gusts around 20 kts until 18Z. After 18Z, conditions will likely return to VFR with decreasing winds, especially after sunset.

Extended Aviation Outlook: VFR through mid-week.

MARINE

The surface cold front will push offshore during the pre-dawn hours this morning. In the wake of the front, winds will turn from the northwest, with gusts increasing for a few hours this morning. Remaining Small Craft Advisories will remain in effect until this afternoon, highlighting gusty winds and elevated seas. High pressure build across the marine zones today and will remain into the mid- week. Fair conditions expected across the marine zones this evening through Wednesday. Very warm and humid conditions are forecast to build across the region Thursday and Friday. Given shelf water temperatures around 50 degrees, wind directions parallel to the coast, and dewpoints around 60 degrees, sea fog is possible during the late work week. At this time, a mention of patchy sea fog will be limited to Thursday night. Increasing rain chances on Friday into Friday night may disrupt any sea fog. However, if rain chances decrease then the potential for sea fog will increase.

CLIMATE

Record High Temperatures:

February 20: KCHS: 82/2018 KCXM: 78/1918 KSAV: 84/1991

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...Small Craft Advisory until 5 PM EST this afternoon for AMZ350- 374. Small Craft Advisory until 1 PM EST this afternoon for AMZ352.