Issued: 6pm on Wednesday, January 15th 2020
Technical Forecast Discussion
Short Term (Wednesday 1/15 through Saturday 1/18)
As of 22z Wednesday, an occluded surface low is currently directed over northern Ohio with its southerly extending cold front advancing onto SE Ohio. This FROPA will be anticipated over the next few hours and between 23z-02z Thursday. This surface boundary will be deprived of moisture and structured precipitation as much drier air resides within much of the lower-upper atmosphere (850mb-400mb). However, cloud cover will remain increased near the surface as light and isolated rain showers may develop ahead and along the approaching front later this evening. Mid-lower level CAA and flow aloft will moderately increase overnight and into Thursday morning following the aforementioned FROPA, which will significantly impact Thursday’s high temperature. These temperatures will progressively fall overnight from the mid-40s until dipping into the upper 30s by the early afternoon hours. In addition, this extended cloud cover will stick around into Thursday afternoon, exclusively near the surface as this lower-level moisture remains hesitant to leave. A decent break in this cloud cover will likely be seen later Thursday afternoon as high pressure ~1038mb and upper level ridging progresses eastward throughout the Great Plains region. Much higher surface pressure ~1044mb will advance over the Great Lakes Thursday night into Friday generating a weak northeasterly flow onto the region. This circulation and subtle increase in cloud cover late week will maintain seasonable temperatures within the upper 30s/lower 40s through Friday. Upper-level troughing will quickly follow behind the exiting ridge with cyclogenesis developing across the easterly portion of Colorado by the afternoon on Friday. Following the left exit region of an upper level jet, this Colorado Low will propagate further into southern Wisconsin by 12z Saturday, which will lift a warm front just north of the region. Surface winds will greatly being to veer southerly Friday night as low-level moisture advection begins to increase. Precipitation will likely begin early Saturday morning with the increasing presence of the aforementioned warm front. Temperatures near the surface overnight into Saturday morning are anticipated to be at or below freezing keeping any falling precipitation primarily snowflakes. However, as the early morning hours progress between 09z-12z Saturday, a deep warm layer slightly above the surface may transition these snow showers over to a brief mix/freezing rain in before rain taking over by noon. This surface low will lift further northeasterly and advance a cold front onto the region later Saturday afternoon. Following this FROPA, lingering precipitation will transition back over to a snow as temperatures fall well below freezing. Snowfall accumulation will be minimal and likely below half an inch, whereas Total Precipitation Accumulation through Sunday morning is currently projected between 0.50″-0.75″.
Long Term (Sunday 1/19 through Tuesday 1/21)
High pressure will progressively filter into the region, keeping weather conditions dry throughout this long term. Amplified upper-level troughing will remain fixed across the eastern U.S throughout Tuesday, which will influence a northerly flow and introduction to a cooler air mass. The return of these cooler ‘winter-like’ temperatures will likely last through the midweek of next week.
(*Next Technical Discussion will be posted on Sunday 1/19*)