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Wednesday night will be cloudy with a low between 58-62. Showers are likely throughout the day Thursday with the chance of thunderstorms in the evening, which has a possibility to be strong. Highs Thursday will be 73-77. Thursday night will be cloudy with a low 64-68. The high for Friday, 64-68, will occur in the morning and temperatures will progressively decrease throughout the day. Saturday will be sunny with a high of 52-56.
Forecasters: Heaven, Munley, Abruzzo, Dowell
Issued: 5:15 p.m. ; October 9, 2019
Technical Discussion (The nerdy stuff we are discussing in class!)
Current WPC guidance suggests a non-NAM blend for the forecast period, and as such the 12Z GFS will be used, along with the 15Z SREF.
Wednesday night will see the continuation of WAA into the area, with temperatures expected to stay rather warm, given the cloud cover also helping to insulate the surface. There is some low dbZ values on radar near Columbia, however given METARs and a significant dry layer near the surface, no rainfall is expected until tomorrow. Rain is expected to be on and off in Columbia, with most of our rain coming from convection throughout the day. Rumbles of thunder are likely throughout the day. Thursday night will see a decent shot at strong thunderstorms ahead of the cold front to our west. Dynamic support is good, with good positioning of the jet at 250mb and the LLJ at 850mb. PWAT values are good, with values around 1.5in, along with soundings indicating ~1500J/kg of CAPE with minimal CIN. Wind profiles and helicity values near 200m2/s2 point towards the possibility of rotating updrafts, however, these storms are expected to be elevated. There is a inversion incredibly close to the surface, which will allow for the possibility for surface based convection to take place if surface temperatures increase a few degrees. This is not expected to happen due to the rain earlier in the day, cloud cover, and the evaporative cooling that will come with this rainfall, but the possibility still remains if enough heating happens. The main threat of this system is expected to be hail and winds. Hail would be associated with any sustained updrafts, which seems rather unlikely, but possible. DCAPE values max out around 850J/kg, which is a decent amount below typical severe parameters. Lapse rates are also rather poor, with values around 6.5C/km for both the 700-500mb and 850-500mb levels. Severe weather is not expected at this time, however strong storms are possible. Thursday night low and Friday high are expected to happen in the same moment, at midnight on Thursday, as that is about the time expected for the front to pass. 15Z SREF Temperature guidance currently has a huge amount of spread among its members, with about 18 hours of spread at which point members expect FROPA. This forecast leans toward the warmer members of the SREF, as we expect FROPA a little after midnight. All members seem in rather good agreement after they push the front through, with strong CAA beginning directly after FROPA. The cooler members of the SREF pull values to near 30F, while those with a later cold front passage will hang around 32. SREF mean currently dips below freezing late Friday night. Saturday will see cooler temperatures, with no rain expected for homecoming. Weak WAA will be intermittent during the day Saturday, as the surface low to our north with start to bring some warm air out of the southwest. This WAA seems to not hold together well, with the lines of thickness regularly going parallel to MSLP, along with solenoids breaking down and reforming during various timesteps during the day Saturday. This will bump our temperatures up a little bit, but it will still be quite cool outside.