textproduct: Columbia

SYNOPSIS

A major warmup begins Thursday with near record temperatures expected through Sunday. The next storm system impacts our area Sunday into Monday as a cold front moves into the area, followed by much cooler temperatures next week.

NEAR TERM /THROUGH TONIGHT/

Key Message(s):

- Isolated showers and storms will remain possible overnight.

With the loss of heating this evening, stronger storm activity has weakened. Focus for showers and storms shifts more into the upstate of SC overnight, but still can not rule out isolated showers or storms throughout the remainder of the night over the forecast area. With lingering low level moisture , expecting another night with low stratus likely developing despite increasing 850 mb flow to around 25-35 kts and thus increased surface winds. Cloud cover will keep overnight lows toward the mid to upper 60s.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Key Message(s):

- Steady warmup begins. - Near record highs Friday.

Throughout Thursday, low level southerly component flow and warm advection will strengthen over the area. Heights will consequently build as the broad 500mb flow pattern aloft amplifies as a series of troughs dig into the SE CONUS. As a result, well above average temps are expected across the forecast area as highs climb into mid to upper 80s, despite widespread cloud cover especially in the morning. Isentropic lift is fairly weak within the warm advection regime, but enough upslope flow will likely produce some showers in the Upstate. During peak heating, some of these showers could sneak into the western Midlands but latest guidance keeps most areas dry. With subsidence inversion stronger, removed pops from the western Midlands.

Friday and Friday night...Upper ridge centered offshore strengthens a bit and heights aloft rise. Subsidence appears stronger than Thursday and moisture remains confined to the low-levels around 850mb. There may be a few isolated showers around the periphery of the ridge but mainly west of the Midlands. ECMWF EFI indicates temperatures well above normal. So went with temperatures above the NBM means, near record highs. Overnight lows above normal.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Key Message(s):

- Highly anomalous warmth expected with near record high temps through Sunday.

There has not been much change in the overall thinking through the weekend with the long term period dominated by deep mid- upper level ridging and an extremely strong offshore surface high. These will yield near or exceeding record high temps across much of the area starting Thursday and lasting through Sunday; the timing of when the next front actually clears the area next week is still uncertain. The ECMWF and its ensembles continues to be slower than the GFS/GEFS. The NBM pops remain high through Monday. Regardless, high temps well into the 80's or low 90's are expected during this window, with a remarkable signal in the EC EFI and NAEFS for anomalous max and min temps. EC EFI shows consistent 0.9+ with SoT of over 1.0 for both max and min temps. NAEFS shows near record 500mb heights off the Atlantic coast with near the 99th percentile heights and temps through Saturday night. So overall, guidance is flagging this period as one of the more anomalous temp patterns we have seen in awhile.

The upper ridge breaks down Sunday into Monday as the upper low out west moves toward the southern Plains. Given the deep moisture available ahead of the front, there is some severe potential but lots to figure out regarding the synoptic forcing and shear; SPC has a small area of the CSRA in a Day 5 outlook (Sunday).The ECMWF is slower/less progressive/less amplitude with northern stream trough than GEFS. CMC ensemble appears slower too. So front may hang up in the area and qpf could be higher but in general the guidance indicates 1-1.5 inches possible. A notable cool-down into the extended range after the frontal passage. Near-below average temperatures throughout next week as the deep troughing slowly digs into the eastern CONUS.

AVIATION /01Z THURSDAY THROUGH MONDAY/

VFR conditions to start off the evening, then ceilings develop and lower into MVFR as stratus deck forms overnight. A return to vfr possible late in the taf period on Thursday.

Most shower activity has moved away from terminals across the forecast area this evening. Still can not rule out an isolated shower overnight, but confidence not high enough to include any mention on forecasts. Increasing low level moisture moving inland will help to develop another night of mvfr/ifr ceilings later tonight over the entire forecast area, lasting through Thursday late morning. Fog should be less likely due to a strong enough low level jet and expected mixing. The jet will be around 25-35 kts at 850mb, and this should allow winds to remain elevated overnight.

EXTENDED AVIATION OUTLOOK... Another day with the threat of early morning restrictions continues on Friday with continued low level moisture in place. Precipitation remains unlikely through Saturday before the next rain chance moves in Sunday.

CAE WATCHES/WARNINGS/ADVISORIES

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