textproduct: Greenville-Spartanburg

SYNOPSIS

Dry but mild high pressure remains over the area through Monday. A moist cold front will cross the area in the Wednesday time frame, ushering in much cooler temperatures behind it.

NEAR TERM /THROUGH TONIGHT/

As of 1101 PM Saturday: Persistent split flow regime continues to dominate the synoptic pattern across the country with a belt of perturbed northern stream westerlies draped from British Columbia to the Great Lakes into New England. Farther south, a lead shortwave trough within the southern stream is quickly sliding off the Carolina coast with a trailing cutoff closed upper low spinning over the Desert Southwest. A trough dropping through the Great Lakes has helped push a surface cold front through the area with dry and cool advection ushering in a cooler airmass. While cooler, temperatures will still be a good bit above average for late November, just not challenging record highs. Surface high pressure sliding across the Great Plains will become centered over the Appalachians Sunday into Sunday night. At least some degree of wind will keep the boundary layer weakly mixed tonight with lows in the low 40s to low 50s. Afternoon highs will warm into the low 60s to low 70s beneath mostly sunny skies for a rather pleasant day. Radiational cooling is expected to maximize Sunday night into Monday morning as the boundary layer decouples in the presence of calm winds and clear skies. This should allow temperatures to fall into the mid 30s to mid 40s by daybreak Monday morning with a few instances of low 30s not out of the question in favored cool drainage areas.

SHORT TERM /MONDAY THROUGH WEDNESDAY/

As of 1220 AM EST Sunday: High pressure over the area Monday slides east Monday night as a cold from approaches from the west. Dry conditions continue but increasing clouds expected in the developing deep southwesterly flow. Highs will be 5 to 10 degrees above normal. Lows will be around 10 degrees above normal.

A short wave associated with a dampening upper low moving by to our north crosses the area Tuesday. This will push a cold front toward the area. A wave of low pressure moves along the front. Deep moisture and forcing are expected, bringing categorical to likely rain chances into the area. There could be a weak CAD develop Tuesday and the precip moves in. A stronger short wave rotating around and upper low moving into the Great Lakes crosses the area Wednesday. This pushes the front into and across the area. There area still some timing differences, but the guidance does appear to be trending to a later Wednesday FROPA. As a result, the guidance all now show sbCAPE into the 500 J/kg range, which is near the muCAPE values and higher than yesterday's guidance showed. Ensemble means are also showing this increase, although they do keep the chance of sbCAPE greater than 500 J/kg on the low side. Bulk shear increases into the 40 to 50 kt range. This could indicate and increased potential for some severe storms, but uncertainty remains. Obviously, this will be monitored as the day approaches. With the forcing, deep moisture, and convective potential, some heavy rain is also possible. The dry antecedent conditions will help limit the flood threat, which will also be watched.

Highs Tuesday will be a few degrees above normal where the CAD develops and potentially 10 degrees above normal outside of the CAD or if the CAD doesn't develop. Lows Tuesday night will be 15 to 20 degrees above normal, keeping the precip all liquid. Highs Wednesday could be 10 to 15 degrees above normal, depending on frontal and convective evolution.

LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/

As of 1245 AM EST Sunday: Heights fall Thursday as a secondary short wave rotates around the upper low and across the area. A flat ridge moves in Friday then moves east Saturday as a trough moves into the central CONUS. At the surface, cold and dry high pressure builds into the area Thursday and Friday, then moves east Saturday as another cold front approaches from the west. Saturday looks to remain dry at this time even as a moist southwesterly flow develops and clouds increase. Lows Thursday will be near to slightly below normal with highs 5 to 10 degrees below normal. Lows and highs Friday and Saturday will be 5 to 10 degrees below normal.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

At KCLT and elsewhere: VFR conditions will prevail at all terminals through the TAF period. A few patches of mid-level stratus are apparent this morning, but ceilings remain high enough that no restrictions are expected. Clouds should clear through the morning with mostly clear skies prevailing through the remainder of the period. Winds will be light out of the north today with the potential for a few Upstate sites to see a brief shift to out of the south/southwest this afternoon. Winds will be light to calm overnight as high pressure settles over the region.

Outlook: Expect dry, VFR conditions to continue thru Monday with the potential for mountain valley fog/low stratus each morning. Shower and thunderstorm chances and associated restrictions, return Tuesday into Wednesday as a moist cold front moves into our area.

GSP WATCHES/WARNINGS/ADVISORIES

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