textproduct: Charleston

WHAT HAS CHANGED

All Key Messages and sections were updated.

KEY MESSAGES

- 1) Record-setting heat possible again today as dry weather continues.

- 2) A cold front will bring low end rain chances Sunday, followed by a brief cooldown early next week.

- 3) Minor coastal flooding possible along the South Carolina coast with the evening high tides this weekend.

DISCUSSION

KEY MESSAGE 1: Record-setting heat possible again today as dry weather continues.

Upper level ridging lingers overhead, with latest observations showing mostly sunny skies and temperatures in the 80s. With the aid of south/southwesterly flow, should see these values rise into the low to mid 90s later this afternoon which may once again challenge daily records (see CLIMATE section below).

Additionally, the latest Drought Monitor indicates D4/Exceptional Drought over a small portion of interior southeast GA, with a recent expansion of the D3/Extreme Drought to encompass much of the remaining area. These persistent, very dry conditions combined with RH values dipping into the mid-20s ahead of the sea breeze again this afternoon merit attention from a fire weather standpoint, though wind gusts coincident with these min RHs only reaching to around 15 mph preclude the need for any fire weather hazard products. Nonetheless, we encourage folks to exercise caution with any activity that may cause a spark.

KEY MESSAGE 2: A cold front will bring low end rain chances Sunday, followed by a brief cooldown early next week.

Near term guidance indicates that a cold front will sweep across SE GA/SC during the daylight hours Sunday. The cold air advection in the wake of the front is strong enough to result in cooling temperatures beginning during the early afternoon hours. Temperatures should peak just prior to the front in the low to mid 80s, during the mid-day hours.

As noted in the previous discussion, latest CAMs continue to show a line of showers and thunderstorms pushing east across the Southern Appalachians late Saturday night into Sunday. By the time this line reaches our area, coverage looks to become more isolated to scattered in nature - though dry air in the low to mid levels may keep coverage entirely isolated. As a result, expect rainfall totals around a few hundredths at best. With rain chances forecast to remain minimal for the remainder of the extended period, should also expect drought conditions to persist and likely worsen as we head into the end of April.

Otherwise, look for a brief, but notable cool down to occur in the wake of FROPA Monday and Tuesday as highs dip back into the 70s. Lows in the upper 40s to lower 50s will also be common during this time. Temperatures then moderate back into the 80s by mid-week.

KEY MESSAGE 3: Minor coastal flooding possible along the South Carolina coast with the evening high tides this weekend.

The combination of the new moon (yesterday) and perigee (tomorrow) will bring elevated astronomical tidal ranges this weekend into early next week. Minor coastal flooding is possible with this evening's high tide along the South Carolina coast. Tide levels will be elevated again with the Sunday evening high tide, but the coastal flooding threat is uncertain and dependent on the timing of the cold frontal passage during the day and the direction of the post-frontal winds.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Prevailing VFR through the 18Z TAF period. Gusty SW winds this afternoon will diminish with nightfall. A cold front will push through the region tomorrow, with winds shifting to the NW by noontime Sunday. There is a very low threat of an isolated shower at all terminals tomorrow afternoon, however this threat is just outside of the 18Z TAF period.

Extended Aviation Outlook: Gusty winds are possible Sunday afternoon and evening.

MARINE

Light to moderate southerly winds prevail across the coastal waters today, with gusty winds developing nearshore this afternoon with the sea breeze. The gradient begins to tighten tonight as a cold front approaches from the west with 20 kt gusts becoming more frequent through the early morning hours Sunday.

A strong cold front is expected to sweep across the marine zones Sunday afternoon. Winds will veer from the NNE by Sunday evening, with gusts between 25-30 kts outside the Charleston Harbor. Seas are forecast to build from 2-3 ft on Sunday to 3-8 ft by dawn Monday. A portion of the marine zones may be highlighted with Small Craft Advisories to highlight the gusty winds and building wave heights. High pressure will return over the region on Monday, remaining into the mid-week. Conditions appear to remain less than Small Craft Advisory criteria.

Rip Currents: A Moderate Risk of rip currents remains in place for all beaches through Sunday due to the combination of 2-3 ft breakers, modest onshore flow, and increasing astronomical influences associated with lunar perigee/new moon. An elevated risk for rip currents remains possible Monday as a pinched gradient associated with a passing cold front supports a gusty northeast wind event along the Southeast Coast.

CLIMATE

Record High Temperatures:

April 18: KCHS: 92/1967 KSAV: 93/1967

CHS WATCHES/WARNINGS/ADVISORIES

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