Friday, 23 Sept 2011 Extended Pow County Forecast

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL DOMINATE WEATHER ACROSS THE EASTERN 1/3 OF IOWA INTO NEXT WEEK. TODAY AND TONIGHT THIS SYSTEM WILL REMAIN OVER WISCONSIN AND ILLINOIS SPREADING CLOUDS ACROSS EASTERN IOWA...THEN DRIFT SLOWLY WESTWARD INTO IOWA SUNDAY WITH THICKER CLOUDS AND AN ISOLATED SHOWER OR TWO ESPECIALLY EAST OF A LINE FROM OTTUMWA TO IOWA CITY TO LA CROSS WISCONSIN.  A STRAY SHOWER CAN'T BE RULED OUT FROM POW COUNTY EASTWARD.  THE LOW PRESSURE SYSTEM WILL THEN MOVE AWAY TO THE EAST ON TUESDAY BRINGING PLEASANT AND WARMER WEATHER WITH TEMPERATURES APPROACHING 80 DEGREES IN SOME AREAS ON WEDNESDAY.


Today thru Wed 23rd - 28th: Mainly Dry thru the period (may see a shower Sunday) with High Temps ranging from the Low 60's thru Monday to the Mid 70's by Tuesday and near 80 Wed. Low Temps will increase from Low 40's Saturday to the Lower 50's Tuesday.

Thursday thru Thursday 29th - Oct 6th: Dry and Breezy the 29th/30th with temps in the Low 80's - Windy and Rain on the 2nd/3rd with temps in the Mid 60's.

Fri thru Sun 7th-9t: Dry and Cool.

Winter 2011/12.

The basis for my forecast is the likely formation of a weak La Nina (cooling waters in the South Pacific) forming and continuing through the winter. Last years "strong" La Nina combined with high pressure over the North Atlantic lead to heavy snows across the Midwest and Northeast. Subtle changes will take place in the weather pattern (primarily a weakening dome of high pressure over the southwest U.S.) that force systems west to east out of the Central U.S. Rocky Mountains, causing a major dip in the jet stream over the eastern half of the country (East of the Miss River). This pattern would put Iowa at the leading edge of a storm track that would give us near normal temperatures leading into winter, and below normal temperatures going out. It would put the north and west 2/3 of the state slightly above normal for precipitation, and the south and east 1/3 of state at, or slightly below normal.


Iowa Winter Weather:

The southeastern 1/3 of Iowa will see Near Normal Snowfall, while the rest of Iowa will see 3-5 inches Above Normal.



What will the Winter of 2011/12 bring?
Here's my best guess right now. I'll refine it as time goes on. It may change - but it won't change a lot.......


Pow County will see Seasonal "Average Daily" Temps up thru Dec - then Jan, Feb, and Mar will be 3 Degrees Below Average.


Nov:
Average Snowfall - 2.1"
Forecast - 2.5"

Dec:
Average Snowfall - 6.5"
Forecast - 7.5"

Jan:
Average Snowfall - 8.1"
Forecast - 10"

Feb:
Average Snowfall - 7.2"
Forecast - 8.5"

Mar:
Average Snowfall - 3.8"
Forecast - 4.5"

Our Average Snowfall between November and March is 27.7". I'm forecasting a Total Snowfall of 33.0" - which is 5.3" Above Normal for the time period.

April: We'll see an inch or two early April.