We have experienced a cool week here in Warren County with frost advisory most mornings and cools starts to the day. Tonight a Freeze Advisory has been issued by the NWS in Louisville valid until 8 am CDT tomorrow. Tonight, we will have clear skies over the area allowing the temperature to drop lower than previous forecast lows. Overnight, an area of high pressure with slide over the area and move out to the east into Thursday. This will keep our skies mostly clear and morning lows low.
Our next chance for showers and thunderstorms will come Thursday night as another trough axis swings through the upper levels. A merging/splitting pattern of the polar jet and subtropical jet will provide enhanced difluent flow aloft which will provide some upper level support for thunderstorm development. Moisture will again be somewhat limited with northerly winds advecting dry air from a cold air mass over the great lakes and Dakotas over our area. A warm front will move north from the south west and cause and increase in clouds by Thursday night. This will allow us to warm temperatures a few degrees as the warm front passes Friday-Saturday and winds shift from the north west to the south east gradually into Thursday night.
Looking into the weekend, we see a powerful system develop off the west in the form of a cut off low that develops off the west coast and slowly wobbles our way with fast moving winds circulating through it at the 500 mb and 250 mb levels. This system will drag over the Rockies and develop an associated surface low as it passes over the mountains and into the lower plains. As this system progresses, the low will be reabsorbed into the polar jet flow Saturday night into Sunday as it progresses towards our area. The next forecast update will detail the expectations for this system further.
Thursday: High, 65. Low, 50. Clouds increasing into the night as another weather system moves in. 30% chance of showers and thunderstorms Thursday night.
Friday: High, 70. Low, 50. Left over precipitation will move out with temps warming back up.