MYRTLE BEACH S.C. (WBTW) — A heat advisory has been issued by the National Weather Service. The alert will be in effect from now until 7 p.m. Heat index values are already in the triple digits throughout the area, but indices are likely to top out between 105-107 degrees. Air temperatures will once again be in the low-90s for the Grand Strand and mid-upper-90s inland. Partly sunny and dry conditions will finish up today, and another muggy and mild night lies ahead.

Partly cloudy conditions will take center stage tonight and temperatures will once again be roughly five degrees above normal. The Pee Dee will range from 75-78 degrees, and the beaches will be in the upper-70s to near 80 degrees.

Luckily, big changes are on the way for the weekend. A cold front will attempt to pass through the area on Saturday. Currently, timing on the front places the boundary along the border belt in the mid-afternoon which is when the atmosphere is the most unstable due to rising warm air from incoming heat. Numerous showers and thunderstorms will overtake the area from noon until after sunset.

The Storm Prediction Center has our area in “general thunderstorms”, which is a level 0/5, so the thunderstorms tomorrow are not expected to be severe, but a couple of strong thunderstorms with heavy downpours and gusty winds will be possible.

One positive of the cold front is that temperatures will be knocked down five degrees or so. The beaches will cap out near 90 degrees and inland will be in the mid-90s on Saturday. Rain chances will linger through Sunday as the cold front hangs out near the border belt, but Saturday is the main rain event. Temperatures on Sunday will cool by another degree or so.

The cold front will not push fully through the area, so dewpoints will not be changing; therefore, it will still be extremely humid.

Here is a model comparison of what the GFS/EURO/Baron3k are projecting for rainfall totals through 11 p.m. on Sunday.

Lumberton: 3″/1.3″/1.1″

Laurinburg: 2.2″/0.62″/0.06″

Florence: 0.26″/0.5″/0.49″

Myrtle Beach: 0.22″/0.86″/0.86″

There is an agreement between the EURO and the Baron3k. Both agree that Lumberton will likely get around an inch of rain, half an inch in Florence, and over 0.75″ in Myrtle Beach. Between these two models, there is not much agreement about Laurinburg. Overall, the trend is that inland, and in particular, the border belt is likely to see the most rain and likely over an inch. Elsewhere, projections are 0.5-1″ with the heavy downpours being isolated.