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Columbia will begin to see chances for pop up storms for the beginning half of the forecast period. Looking around Columbia, one can see towering cumulus around the area, along with some of these showers starting to show up on radar. Temperatures will stay high, as will humidity. Thursday will also see the potential for pop up showers in the afternoon. Any of these pop up storms will begin to fade as the sun goes down. Temperatures will remain high through Thursday, with high temperatures in the low 90s to high 80s. Friday looks to start off quiet, however rain is expected after noon. Temperatures thus will not be able to get quite as high, however temperatures will still stay in the mid 80s. Saturday will see even more rain, with a similar temperature to Friday.
Forecasters: Heaven, Dowell
Issued: 4:20 p.m. ; September 18, 2019
Technical Discussion (The nerdy stuff we are discussing in class!)
WPC indicates models are not in great agreement on Friday and Saturday, the current reccomendation is GEFS Ensembles; as such, 12Z GFS will be the preferred deterministic model, along with usage of the 15Z SREF, 18Z HRRR, and 12Z GEFS ensembles.
Given current Satellite and radar images, along with 18Z HRRR guidance, pop up storms have been put into the main forecast; GOES East shows the Cu field over Missouri starting to agitate, along with these storms that are starting to rise showing up on radar. These storms are still fairly few and far between, thus the isolated showers. These pop up storms are also present for Thursday afternoon on the 18Z HRRR. The HRRR is pointing towards low level convergence as the reason for these pop ups, along with the current high temperatures and dew points. Friday will begin to see the breakdown of the ridge directly overhead, as the massive trough over the entire western United States begins to finally move east. Soundings from the 12Z GFS show very little vertical motion, and a stratiform style of rain; there is little indication for convective precipitation, if any. Rain is expected Friday afternoon into night, ending overnight for a short period before resuming again on Saturday. 12Z GFS indicates Saturday will see Columbia enter southwesterly flow as we begin to enter the trough. GEFS Ensemble also show us beginning to enter the trough on Saturday. Rain is expected most of the day Saturday. This rain will be very widespread, with soundings from Saturday evening indicating some sort of embedded convection. 700mb Omega also seems to line up with this, giving high omega values Saturday evening. Storms are expected Saturday afternoon.