textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated for the end of the fire danger statement for northeast Georgia.

The forecast for this week remains largely the same, but some added discussion is now provided for possible wintry weather next weekend.

KEY MESSAGES

1. Rain returns to the forecast on Wednesday, before a brief period of drying on Thursday. 2. Another disturbance arrives on Friday, with the potential to bring wintry p-types to the forecast over the weekend. Confidence remains extremely low at this point.

DISCUSSION

Key message 1: Rain returns to the forecast on Wednesday, before a brief period of drying on Thursday.

As broad, low-amplitude z500 ridging continues to shift eastward on Monday night and Tuesday, a moist subtropical air mass will remain in place across the Southeast, driving anomalously warm temperatures climbing as high as the upper 60s or even lower 70s on Tuesday afternoon. Lows on Tuesday night will only fall into the mid 50s for most of the area.

By Wednesday morning, a lobe of southern stream energy will phase with a weak shortwave over the upper Mid-Atlantic to drive a cold front down the Ohio Valley and into the Carolinas. As a result, a cooler and drier air mass should settle into the forecast area through the day, ushering in a round of scattered rain and starting the process of cooling our temps back down. Lo-res ensembles are in better agreement than they were yesterday that this intrusion of drier air will keep the weather quiet on Thursday...in a trend sharp and consistent enough that it's already reflected in the latest NBM.

Key message 2: Another disturbance arrives on Friday, with the potential to bring wintry p-types to the forecast over the weekend. Confidence remains extremely low at this point.

The arrival of another upper-level disturbance embedded in NW flow aloft will prompt reactivation of a remnant boundary to our south, and operational models all depict a resurgence of low-level moist upglide on Friday...accompanied by another round of rain. By this point in time, a mature surface low will be migrating out of the southern Great Plains into the Ozarks, and so as its moist conveyor belt begins intensifying...upglide and associated precipitation should continue through Friday night into Saturday.

Unfortunately, on Friday night and especially Saturday night, forecast temperatures are cold enough to support frozen p-types. Owing to the uncertainty in the exact track and strength of the surface low, the surface high, and the associated upper forcing, there is a wide range of ensemble solutions for what p-type that would actually fall as. However, pattern recognition alone suggests that...with a cold surface layer and strong warm advection in the low levels...freezing rain is not out of the question for at least some portions of the area. It cannot be overstated: confidence remains extremely low at this time scale! But, we'll need to watch the evolution of this system closely. Tiny details that simply cannot be captured with any degree of certainty at this point will make all the difference between an all-rain forecast, a snow forecast, and a freezing rain forecast.

AVIATION /00Z MONDAY THROUGH FRIDAY/

At KCLT and elsewhere: VFR conditions will prevail at all terminals through the TAF period. High clouds continue to stream across the region and will continue to do so through the overnight and into tomorrow morning. Mostly sunny skies should return by late in the period as high clouds finally shift east of the area. Winds will be light and variable and initially out of the east/northeast. By tomorrow afternoon, winds should shift to out of the south.

Outlook: Dry, VFR conditions are expected through Monday. Moisture will return during the middle part of the week, which could result in some ceiling restrictions on Tuesday and Wednesday.

GSP WATCHES/WARNINGS/ADVISORIES

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