Monday, September 15, 2014
Seasonable weather returns
Subsidence accompanying the arrival of an anticyclone over the upper-midwest this evening will provide clearing skies. With light winds and clear skies, radiational cooling will be maximized leading to chilly nights tonight and Tuesday. With full sun, the high temperatures on Tuesday will easily rebound into the mid 60's. A weak but dry frontal passage on Wednesday afternoon will slow the warm-up over the state as another anticyclone builds over the area from southern Canada. As the anticyclone moves east, warm thickness advection will boost temperatures up to and beyond daily normals for the week's end (average daily high temperature for later in the week 70F; low 49F).
The only wrinkle in an otherwise dry forecast for the week, is the overall fate of Hurricane Odile located over the southern Baja Peninsula of Mexico. The remnants of the cyclone (primarily the water vapor) are forecast by the GFS to move into the southwestern US and then northeast to the midwest by weeks end. If this moisture gets entrained into the broad southwesterly flow expected to develop over the central US, a wet Saturday is possible for southern Wisconsin.
Michael C. Morgan