textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No major changes.

KEY MESSAGES

1. Fog may develop across portions of the forecast area this morning before lifting around mid-morning. 2. Dry for the workweek before rain chances return this weekend. Highs will mostly be near to above normal through the week, with the exception Tuesday, when highs drop a few degrees below normal.

DISCUSSION

Key message 1: Fog may develop across portions of the forecast area this morning before lifting around mid-morning.

The wedge reasserts itself through the early morning hours allowing low clouds to build back over most of the GSP forecast area. Patchy fog may develop as well through daybreak, with pockets of dense fog not entirely out of the question. Patchy to locally dense fog looks most likely across much of northeast Georgia, the western South Carolina Upstate, and the North Carolina foothills. The North Carolina mountains may also see patchy fog develop, especially in the mountain valleys. Any fog that develops should lift by mid- morning but mostly cloudy skies will linger through the morning hours before sunshine gradually returns from west to east this afternoon and into this evening.

Key message 2: Dry for the workweek before rain chances return this weekend. Highs will mostly be near to above normal through the week, with the exception Tuesday, when highs drop a few degrees below normal.

Upper troughing lingers over the northern and eastern United states through Friday. At the surface, dry high pressure builds in from the north through Tuesday before the center shifts offshore the Mid- Atlantic Coast Wednesday. Another area of high pressure builds in from the northwest Thursday into Friday keeping dry conditions around. We will see a brief warm up today before slightly cooler and just below normal highs return Tuesday. A warming trend develops Wednesday into Thursday, with highs climbing back into the low to mid 80s across the mountain valleys and east of the mountains on Thursday. Slightly cooler highs return Friday, ranging from the upper 70s to lower 80s across the mountain valleys and east of the mountains.

An upper ridge in the western Atlantic builds westward towards the Southeast coast while an upper low develops over Texas and lifts northward over the weekend. These two systems will work together to funnel in Gulf moisture over the region. And there will be plenty of moisture thanks to a frontal boundary nudging northward out of the northern Gulf as an area of low pressure develops in the western Gulf this weekend. This will bring rain chances back but exact timing remains murky as global models are not in great agreement on the arrival time of rain. The GFS and Euro are in fairly good agreement that dry conditions will linger through Saturday, before rain chances return Saturday night into Sunday. Meanwhile, the Canadian is the faster solution, showing rain chances returning by Saturday afternoon. NBM chance PoPs on Saturday appear reasonable for now. Cooler highs should return for the weekend with thick cloud cover and widespread rain in place, especially on Sunday.

AVIATION /06Z MONDAY THROUGH FRIDAY/

At KCLT and elsewhere: A quite tricky aviation forecast over the next 6-9 hours, as a thick blanket of high clouds persists over the region...atop a very moist/residual cold air damming air mass. Cigs are mainly VFR early this morning, except for low MVFR at KGMU/KGSP...and a recent appearance of LIFR at KHKY. Moisture is more than adequate for widespread fog/low stratus, but the high clouds are the fly in the ointment...possibly preventing the necessary cooling that will allow for complete saturation of the near-surface layer. Due to the inherent uncertainty, we have made liberal use of tempos...favoring at least a couple of hours of IFR or LIFR at the upstate SC terminals and KHKY, with mainly MVFR advertised at KAVL/KCLT. VFR conditions should prevail by late morning, with clearing high clouds expected into the afternoon... followed by mostly SKC conditions from later this afternoon through the end of the forecast period.

Outlook: VFR conditions are expected to prevail through the week...except for potential mountain valley fog and low stratus each morning.

GSP WATCHES/WARNINGS/ADVISORIES

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