Thanks to IconArchive.com for the icons!
Tonight, we will see cloudy skies with storms in the evening, up to around midnight. The low will be about 60 to 64. On Thursday, skies will continue to be cloudy with highs reaching 66 to 70. Thursday night, cloudy skies along with cooler air from the north that will cause temperatures to dip to about 46 to 50 degrees. Friday will bring mostly cloudy skies and a high of around 64 to 68. Saturday will also bring cloudy skies, with a high of 74 to 78.
Forecasters: Heaven, Abruzzo
Issued: 4:30 p.m. ; October 2, 2019
Technical Discussion (The nerdy stuff we are discussing in class!)
Given current WPC analysis, 12Z GFS will be the primary model used, with 15Z SREF used as a supplement.
Wednesday night will finally see the passage of the cold front that has been looming to the west all day. Expected precipitation will be associated with a linear MCS. DCAPE values are looking particularly unimpressive, with soundings indicating sub 1000 J/kg. SREF also points to only about a 30% chance of DCAPE above 1000J/kg. Lapse rates are also particularly unimpressive, with both mid and low level lapse rates of about 5C/km. This system does seem to have decent dynamic support, with good divergence at 250mb. 850mb jet also seems to be fairly supportive of the system. Even though the dynamics are good, the setup is still too thermodynamically weak. Storms are expected, and some have the chance to be strong, however severe storms seem unlikely for Columbia. Thursday will see the start of CAA in the afternoon, although the GFS indicates this CAA will be rather weak; solenoids are long, with lines of thickness skewed a little bit off perpendicular. There will still be enough CAA advection to keep temps low in the afternoon. CAA will cease late Thursday, with the massive surface high to our northeast moving to be directly north. While not directly in CAA advection on Friday, values of thickness will be pushed south with the high to our north. These lines of thickness will be parallel to MSLP, with winds out of the east, but a slightly lower temperature is expected Friday. Late Friday night will see the start of WAA into the Columbia. This axis of WAA will be incredibly tall, with WAA starting in southern Missouri and ending in northern Quebec. The surface high that was off to our north will at this point be off to our northeast, and working in conjunction with a surface low to the northwest to advect warm air into the area. As such, a fairly significant 10 degree increase is expected from Friday into Saturday. Saturday seems to have the possibility for storms, as Columbia will be very near the triple point based off the occluded front attached to the low to our northwest. The period for storms currently seems incredibly brief, and as such, we have currently opted for no rainfall on Saturday, however this situation will need to be updated with fresh guidance when possible. Skew Ts from Saturday were rather impressive for early October, with 1500 J/kg of CAPE and minimal CINH. Again, however, this sounding is for exclusively 1 time period. While the environment is expected to change a lot in the next 24 hours, this event that is possible for Saturday will absolutely need to be updated at the next available period after cold frontal passage. Additionally, SREF guidance currently has a mean value for MUCAPE on Saturday of around 500 J/kg.