866 FXUS62 KCAE 130855 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 355 AM EST Sat Feb 13 2021 .SYNOPSIS... Cold air damming pattern will continue through the weekend with below normal temperatures and periods of rain and drizzle. The rain chances will continue into early next week as a low pressure system moves into the area. && .NEAR TERM /THROUGH TONIGHT/... Wedge remains entrenched across the region with temperatures in the upper 30s to low 40s across the forecast area. Satellite and WSR-88D imagery shows relatively low and warm cloud tops currently over the area with cooler cloud tops moving through GA. MRMS currently shows scattered showers in the central and northern Midlands with more widespread coverage moving into southern GA. Overnight increasing isentropic ascent will again result in rain overspreading the area with intensity increasing toward daybreak in the CSRA and southern Midlands. With the wedge in place temperatures will only fall a few degrees with mid 30s to around 40 for overnight lows. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Fully expect the CAD wedge to remain in place on Sunday as the trend in MOS guidance continues to get cooler with each run. The next low pressure system will be lifting northward from the eastern Gulf of Mexico on Sunday as shortwave energy rounding the base of the upper trough to the west lifts northeastward out of the Gulf of Mexico over the region. The wedge front will remain pinned near the coast as weak low pressure lifts north along that baroclinic zone and isentropic lift increases over the forecast area Sunday. The strongest moisture transport remains near the coast and expect the convective rainfall and highest rain rates to also remain east of our area but still expect to see significant rain with 0.5-1.0 inches of rain Sunday into Sunday night. There should be a break in the rain late Sunday night into Monday as the forecast area falls in the wake of the departing shortwave trough and slightly lower PWATs move over the region. However, the break will be short lived as significant moisture advection returns late Monday and Monday night ahead of yet another strong low pressure system lifting northeastward out of the Gulf of Mexico. PWATs rise to near 1.5 inches, nearly 200 percent of normal, Monday night with strong moisture transport over the region driven by a 50 to 60 knot southwesterly 850mb jet. There is the potential of some instability reaching the forecast area if the strong southwesterly flow erodes the CAD wedge, and if that does occur, an isolated severe storm cannot be ruled out given the very strong shear, although confidence remains low at this time. Expect the potential for another round of a half inch or more of rain across the area with this system. Temperatures will be well below normal on Sunday deep in the CAD wedge air mass and will continue to go below MOS guidance leaning closer to the NAM and raw consensus for temperatures. Monday may be slightly warmer according to the guidance but history in these strong CAD events leads me to think temps will remain well below normal and lower than guidance suggests for highs, at least until Monday night when the wedge may break in the strong southwesterly flow. && .LONG TERM /TUESDAY THROUGH FRIDAY/... There is a general consensus among the ensembles favoring a mean trough over the middle of the country during this period. This will keep a persistent southwesterly flow aloft over the region and result in generally above normal temperatures. The forecast area will be between low pressure systems mid week as the first low pressure system lifts away from the area early Tuesday with a relatively dry air mass briefly building over the region into Wednesday. The next deep upper trough will dig into the Plains and Mississippi Valley Wednesday night, inducing low pressure along the Gulf coast which will lift northeastward through the TN Valley into the Ohio Valley/Mid Atlantic region Thur/Thur night. This will bring rain back into the forecast area by Wednesday night with strong moisture transport continuing over the forecast area through at least Thurs night and possibly into Friday. So the active amplified weather pattern will continue through the end of the week. Confidence is reasonably high in the series of systems bringing active weather to the forecast area with best chances of rain Thursday and Thursday night. Thunderstorms do not appear likely at this point given very little if any instability forecast. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... Mainly IFR through the TAF period, with LIFR predominant through the morning. Moisture continues to move into the region from southwest flow aloft. A cold air wedge is causing prolonged drizzle and rainy conditions through the weekend. Widespread light rain is starting to move in from the southwest, further bringing down visibilities and ceilings. Within more moderate bands of rain, expect ceilings to drop to LIFR then rise once again as they move out. Some periods of MVFR possible after sunrise much like the previous day. Gusts out of the northeast should keep visibilities from lowering to LIFR. EXTENDED AVIATION OUTLOOK...Unsettled conditions will result in periods of widespread and prolonged flight restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$