textproduct: Charleston

WHAT HAS CHANGED

Key Message 1 has been updated for ongoing trends. The Aviation Section has been updated for the 00Z TAF issuance. The Marine Section has been updated for ongoing trends.

KEY MESSAGES

- 1) Below-normal rain chances are expected through the weekend. - 2) Temperatures are expected to rise late this week and through the weekend, likely approaching triple digits this weekend. Heat Advisories could be needed.

DISCUSSION

KEY MESSAGE 1: Below-normal rain chances are expected through the weekend.

Tonight: Hi-res model consensus and the 24/12z HREF suggest any diurnal convection occurring early evening to be limited across an area that includes Beaufort, Jasper, Chatham, Effingham, Bryan, and Liberty counties. However, there remains considerable obstacles to overcome development including copious dry air aloft. Anything that develops will remain relatively weak and short-lived, coming to an end in the next hour or two as surface heating wanes. The overnight period is expected to remain dry for all areas.

For the latter part of the week and into the weekend, the surface pattern is expected to increasingly become dominated by subtropical high pressure. Model consensus is for at best scattered thunderstorm coverage, with the best chances appearing to be Friday, and then perhaps Sunday and Monday. Overall, there aren't any significant features to focus or drive initiation, so development will be dependent on surface heating and perhaps the sea breeze. Also, there does not appear to be any notable severe threat at this time.

KEY MESSAGE 2: Temperatures are expected to rise late this week and through the weekend, likely approaching triple digits this weekend. Heat Advisories could be needed.

The main story for the latter part of the week and through the weekend will be well above normal temperatures. Low to mid 90s are forecast to return by Thursday, mid to upper 90s by Saturday, and near 100 for Sunday into Monday. Dewpoints are also expected to be on the rise, especially from Friday onward, yielding increasing heat index values as well. The probability of heat index values into the 105-110 degree range will rise notably for Saturday through Monday, especially along the coast where the highest dewpoints are anticipated. Confidence in the magnitude of the heat threat remains relatively low this far out, but Heat Advisories could eventually be needed for at least portions of the area.

Additionally, low temperatures will be on the rise each night and we could approach daily record high minimums. See the Climate section below for additional details.

AVIATION /00Z THURSDAY THROUGH MONDAY/

VFR conditions are expected to prevail at CHS/JZI/SAV terminals through 00Z Friday, although an isolated shower/thunderstorm can not be ruled out near the SAV terminal Thursday afternoon.

Extended Aviation Outlook: VFR conditions are expected to prevail.

MARINE

Through Tonight: East winds will gradually turn more southeast into the evening with speeds mostly topping out around 15 kt. Flow will weaken considerably overnight, becoming 5 kt or less late. Seas should mostly average 2-3 feet.

Thursday through Monday: A pretty typical pattern is expected through the weekend and into early next week. Winds will generally be south to southwest, with some modest surging into the 15-20 knot range at times. Winds will increase along the land/sea interface each afternoon and evening with the development of the sea breeze. We could see a period of gusts up to around 25 knots Friday evening through Saturday evening across the Charleston County waters, and a marginal Small Craft Advisory could be needed.

CLIMATE

Record High Temperatures:

June 28: KCHS: 99/1998 KCXM: 100/1959 KSAV: 100/1998

Record High Minimum Temperatures:

June 27: KCHS: 77/2015 KSAV: 79/1952

June 28: KCHS: 78/2013 KCXM: 81/1998 KSAV: 80/1880

June 29: KCHS: 79/1977 KCXM: 83/1998 KSAV: 80/1885

CHS WATCHES/WARNINGS/ADVISORIES

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