textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

The aviation forecast was updated to reflect the 12Z TAF issuance.

KEY MESSAGES

1. Dry again today with very low afternoon RH expected, but wind should not be as strong this afternoon. 2. Above normal warmth returns this weekend into next week, while limited rainfall chances, mainly in the mountains, provide little relief from ongoing drought conditions.

DISCUSSION

Key message 1: Dry again today with very low afternoon RH expected, but wind should not be as strong this afternoon.

If there's one thing that will spoil an otherwise beautiful Spring day, it would be the relatively dry air mass that will remain across the region as sfc high pressure moves from the mtns to the Carolina Coast. Temps will once again be 3-5 degrees on the cool side of normal, but the dewpoint is expected to mix out as it did yesterday, though not quite as dry. The chances of the RH falling below 25 percent in the new HREF are at best around 40 percent across the higher elevations and ridgetops, while most of the area has a prob of 20 percent. We have undercut the model blend accordingly, which brings the min RH this afternoon down into the 20-30 percent range, keeping the fire danger elevated because of the ongoing drought. Fortunately, with the high center moving overhead, wind should stay less than 10 mph.

Key message 2: Above normal warmth returns this weekend into next week, while limited rainfall chances, mainly in the mountains, provide little relief from ongoing drought conditions.

Model guidance shows the amplification of the upper trof/ridge pattern beginning on Saturday, with the mid/upper ridge building along the East Coast through the early part of next week, culminating in an upper anticyclone centered off Cape Hatteras by late Monday. This will keep the sfc high generally off the Southeast Coast in Bermuda High fashion into the middle part of the week, and the circulation around this feature will advect warmer temperatures up from the south while also increasing the low level moisture. As a result, temps rebound back above normal for Saturday, followed by the start of a stretch of Summer-like temps around 8-12 degrees above normal beginning Sunday and extending through the middle part of next week. That will push highs into the upper 80s to lower 90s each afternoon Sunday through Thursday, but probably not hot enough to challenge any records. Dewpoints will also increase into the upper 50s and lower 60s, but that won't be enough to bring the afternoon RH much above 35 percent or so, meaning the air mass will still feel relatively dry, and apparent temperatures will stay close to actual air temperatures.

Unfortunately, the model guidance doesn't hold much promise for rain until perhaps late next week as the pattern becomes more progressive. The GFS looks overly optimistic with shower development over the mtns for Sunday and a more subdued precip prob is favored until the CAMs show some support. Eventually, as the pattern moves forward by mid-week as a strong wave lifts out of the Plains and to our north, the eastern ridge gets pushed offshore and we get into a better SW flow aloft. That allows the trailing front to move eastward at least to the mtns on Wednesday. We shall see if that brings more meaningful rain chances to the region. In general, it would appear to favor better coverage of mainly diurnal convection for Thursday afternoon, so some folks might get lucky, but without anything organized, a lot of places won't get much relief from the drought conditions.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

At KCLT and elsewhere: VFR and dry at all terminals through the period. Starting out this morning with a light/variable wind in most places. Some valley fog is noted on satellite imagery in a few spots in the valleys, but it looks too dry for valley fog around KAVL, so we will monitor. Expect wind to return from SW by late morning. This could become a light cross-wind at KAVL for the afternoon hours. Wind should go light/variable again with sunset.

Outlook: VFR conditions are expected to continue into early next week. Isolated diurnal showers will be possible over the mountains each afternoon beginning on Monday.

GSP WATCHES/WARNINGS/ADVISORIES

GA...None. NC...None. SC...None.