Due to the recent abundant moisture in the lower levels of the atmosphere, the danger for outdoor fires has been kept at a minumum. Near 8 a.m. EDT at the nearest rawinsonde station to the Upper Peninsula, found in Green Bay, the upper-air sounding reported a dew-point depression of only three degrees celsius at the 700 millibar level. This indicates very moist air.
This moist air is associated with an upper-level shortwave trough passing from west to east just north of Lake Superior. At 500 millibars, this trough, now a cut-off low, has an estimated height of 560 decameters. These "low heights" are some of the lowest in the country. The rest of the continental U.S. is dominated by high heights and ridging.
Typically, when the upper-air pattern suggests low heights are moving over an area, that area should expect cooler temperatures. The recent passing of this shortwave trough over the Upper Peninsula can explain why we saw such cool temperatures, for this time of year, over the last few days.
The low-pressure center, reflected from this trough, at the surface, currently has a minimum pressure of 1007 millibars. This low-pressure center is located just to the north of New York state. It is forecast to move further to the east along with the upper-level energy associated with the trough. It will take most of the moisture with it, leaving us with mostly clear skies for a few days.
High pressure at the surface and upper-air ridging return to our forecast for the upcoming week. It will be a weather pattern similar to last week. But, the difference this time is that the lower-level winds will be mainly from the east-southeast instead of directly from the south. The warm-air advection pattern will be much weaker this time around. This means that we'll see warm temperatures again, just not quite as warm as last week.
TV Station Profiles & Public Inspection Files forWLUC