textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

The aviation discussion has been updated for the 12Z TAF issuance.

KEY MESSAGES

1. 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: 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.

Despite abundant low level moisture within residual cold air damming air mass, extensive high clouds have prevented widespread saturation of the low levels, and fog/low clouds have been relatively patchy as a result, with only very isolated dense fog being reported. What fog/stratus there is will lift by late morning.

Otherwise, 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 /12Z MONDAY THROUGH FRIDAY/

At KCLT and elsewhere: As expected, the combination of abundant low level moisture underneath extensive high cloud cover has resulted in a tricky aviation forecast this morning, with widely varying flight categories at the TAF sites...from VFR at KCLT/KAVL...to IFR at the upstate SC terminals...to VLIFR at KHKY. Will rely heavily on obs for this morning's forecast, making use of tempos to advertise the solid potential for brief cig restrictions at KCLT/KAVL. VFR conditions should prevail at all sites by late morning, with clearing high clouds expected through the afternoon... followed by mostly SKC conditions from later this afternoon through the end of the forecast period. The only exception is the anticipated development of fog/low stratus in the mountain valleys late tonight/early Tuesday...with IFR/MVFR visby likely to develop at KAVL by daybreak.

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

GSP WATCHES/WARNINGS/ADVISORIES

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