textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Hot and humid conditions are expected across the area this weekend and through early next week.

DISCUSSION

KEY MESSAGE 1: Hot and humid conditions are expected across the area this weekend and through early next week.

Sunday and Monday will see little change in the synoptic set up, with low pressure in the Northern Gulf and high pressure positioned over the Western Atlantic. This continued set up will allow temperatures to reach into the low to mid 90s each day, with heat index values around 100-105. The current forecast keeps heat index values just shy of Heat Advisory criteria (>108), however Heat Advisories cannot be ruled out, especially along the coastal corridor where the dew points will be highest. The pattern will begin to shift on Tuesday as an upper level trough swings eastward. This will yield greater coverage of afternoon showers/thunderstorms and limit the heat potential each afternoon.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

00Z TAFs: VFR. Winds will increase and become gusty Sunday afternoon due to the formation of the sea breeze.

Extended Aviation Outlook: Predominately VFR conditions through the period, however there is a low chance of brief flight restrictions each afternoon from showers and thunderstorms developing along the seabreeze.

MARINE

Tonight: As the local waters situate between an inland trough and a subtropical high to the east, this will cause the pressure gradient to be elevated. Expect wind speeds to range from 15 to 20 kts with gusts up to 25 kts (especially across the SC nearshore waters). Thus, Small Craft Advisories are in effect. We should have a slight downtrend in wind speeds late tonight, with winds ramping down just prior to sunrise Sunday. Expect seas to be in the 3 to 5 ft range.

Sunday through Wednesday: The marine waters will remain positioned between high pressure to the east and low pressure in the Northern Gulf into early next week. This will yield a pinched pressure gradient and SW winds gusting around 20 knots. Sunday will see gusts as high as 25 knots across the Charleston nearshore waters. A Small Craft Advisory is in effect for this marine zone through Sunday evening. Mid week a trough inland will shift offshore and again enhance the wind gusts. Small Craft Advisories could be needed mid- week, especially in the Charleston nearshore waters and the Charleston Harbor. The National Hurricane Center is monitoring a system in the Northern Gulf for possible tropical development, with a 40% chance of development in the next 7 days. If this system were to develop and track up the SE coastline there would be additional wind and wave concerns across the marine waters.

Rip Currents: The pinched gradient across the marine zones will yield SW wind gusts around 20 knots. Due to the enhanced winds along the coastline there is a Moderate Risk of rip currents at all area beaches tomorrow (Sunday).

CLIMATE

Record High Minimum Temperatures:

July 18: KCHS: 79/2007 KCXM: 81/2007

July 19: KCHS: 79/1986 KCXM: 83/1986

July 20: KCHS: 79/2025 KCXM: 83/2000 KSAV: 79/1942

July 21: KCHS: 80/1986 KCXM: 83/1998

July 22: KCHS: 81/2011 KCXM: 83/2011

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...Small Craft Advisory until 8 PM EDT Sunday for AMZ360. Small Craft Advisory until 6 AM EDT Sunday for AMZ362.