Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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606 FXUS62 KCAE 180809 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 409 AM EDT Thu Apr 18 2024 .SYNOPSIS... A warm and sunny day expected today with warm temperatures and no chance of rain. Moisture will increase Friday and Saturday as a cold front moves into the area. With strong heating, diurnally driven showers and thunderstorms are expected to develop. The front will become stationary near or slightly south of the area Sunday. Deep moisture and lift across the area will result in numerous showers Sunday through early Monday. Temperatures Sunday and Monday are expected to be well below normal. && .NEAR TERM /THROUGH TONIGHT/... Weak shortwave energy is crossing the region early this morning and should clear the high clouds out allowing for a mostly sunny day. PWATs will be falling below an inch this morning as drier air moves in behind the departing shortwave with some subsidence. Surface low pressure will lift northeastward from the Central Plains this morning to the western Ohio Valley by this evening pushing a cold front into the Mississippi Valley remaining well west of our area. Temperatures this afternoon should be warmer than yesterday with plenty of sunshine expected in addition to some downsloping flow with high temperatures expected to be in the upper 80s to around 90 degrees. Temperatures may approach record values at AGS (91 set back in 1896). Deep mixing within a drier air mass should result in low humidities as dewpoints fall into the 40s. Tonight, chances of rain increase after midnight as hi-res guidance shows some showers and possible thunderstorms developing ahead of the front to our west. There is some agreement that any activity that moves into the western Midlands will be weakening as it moves in and will be moving into a drier air mass so will only carry slight chance pops in the western Midlands and upper CSRA tonight. Overnight lows should remain above normal and be similar to this morning with lows in the lower to mid 60s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Shortwave will be moving through the area Friday morning as moisture increases with HREF mean PWATs climbing to above 1.2 inches. Some showers are possible associated with the shortwave from west to east, tapering off mid to late morning with a lack of forcing into the early afternoon limiting the potential for precip until a surface trough shifts into the area by late afternoon into Friday evening, strengthening low level convergence. With temperatures above average once again as highs rise into the mid to upper 80s, expect moderate destabilization with 70% of HREF members showing sbCAPE exceeding 1000 J/kg. CAMs indicate convection developing along the surface trough, mainly across the northern portion of the forecast area. SPC maintains a marginal severe risk over the entire area. Deep layer shear increases late in the day and while it will likely not be overly impressive, it will support organized multi- cells. Isolated damaging wind gusts or marginally severe hail will be possible with the strongest storms. Storms should dissipate Friday night with a loss of daytime heating. Lows remain mild, in the low to mid 60s. A cold front will be pushed into the area Saturday from the north aand slowly move south through the area which will lead to a tighter temperature gradient with southern portions of the forecast area once again in the upper 80s but along the north, closer to 80. While upper forcing appears to be somewhat limited with zonal flow aloft, surface convergence along the front will support scattered showers and thunderstorms once again, although a bit more uncertainty as to the degree of instability across the forecast area. Chances for showers and even an isolated storm continue overnight with a shortwave expected to move in. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... The front will be near the southern border of the forecast area early Sunday morning with strengthening isentropic lift over the forecast area and a more robust shortwave moving in late in the day leading to widespread rain. Guidance continues to trend more towards an in situ wedge developing Sunday so have continued to go below blended guidance for temperatures, keeping highs mostly in the 60s. There is some uncertainty as to whether or not this wedge breaks into Monday but typically see biases in models of breaking the wedge too early so for now have gone below blended guidance for highs Monday as well and kept at least low chances for rain. Beyond Monday, expect gradual warming trend through mid-week. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... VFR conditions generally expected through the 24hr TAF period. Satellite imagery shows higher clouds continue to move over the area but the back edge should move through during the 09z-12z time frame with mostly clear skies expected through most of the day. Cannot totally rule out some brief MVFR vsbys in fog during the predawn hours at CAE/AGS due to the clearing of higher clouds and diminishing dewpoint depressions, although confidence is limited and guidance is not showing any restrictions. Light and variable winds will pick up from the northwest to west at around 5 knots by 14z as a weak surface trough shifts southeastward through the area. Winds may shift back to the southwest by 20z in response to an approaching frontal boundary. EXTENDED AVIATION OUTLOOK...No significant impacts to aviation expected through Saturday. Restrictions expected on Sunday into Monday with possible developing wedge conditions. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$