A Cold Blast to Finish Out the Week

The surface high pressure system that entered the area yesterday has mostly migrated to the New England states, but is still exhibiting control over our area into the lower Mississippi River valley. A cold front is extending from a surface low pressure center situated just north of Minnesota. The front extends with a SW orientation from Michigan’s Upper Peninsula into central Kansas. Overall, the upper level support is not very prevalent. For one, the 300mb trough has a neutral orientation with the jet max misaligned to the south of the center of surface low pressure. This will inhibit intensification and forward movement of the weather system. Also, there appears to be little positive vorticity advection, which in abundance stimulates lift and support for the surface low and front. The surface high pressure is important because it is preventing any chance of significant moisture advection into our area ahead of the cold front.

Above is the NWS Storm Prediction Center’s Short Range Ensemble Forecast Model valid for 7 AM this Saturday. It is showing probabilities for precipitation of .01 inches during a three hour span. Percentage values are almost nonexistent for our area.

Into Sunday, the upper level trough is shown to remain in its neutral orientation and deepening with the presence of a jet streak. As the jet max goes around the bottom of the trough, it will begin to shallow it out and move it eastward at the start of next week. The surface cold front presently draped across the midwest will likely fizzle out into Friday because of the stationary high pressure and lack of upper level support. The residual high pressure will resume control until being swept out by a cold front on Saturday. This front bearing low will have more support from the jet stream with the cold front looking to impact our area on Saturday afternoon. Because of the high pressure over our the region, the availability of moisture will be a concern and will determine the severity and even occurrence of precipitation associated with the frontal passage. Warm air advection will also be inhibited, which will put in question the strength of the front because of the diminished temperature gradient. Models are currently behind these assumptions with almost no indication of measurable precipitation associated with the frontal passage. With it being three days out, there is still room for error. Behind the front into Sunday, expect cooler temperatures again with a high pressure settling into the region.

Days at a glance:

Thursday: High 75 Low 48

Friday:      High 81 Low 54

Saturday:  High 77 Low 52

Sunday:     High 67 Low 37

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