Wednesday, December 20, 2006

Pre-Christmas Winter Storm

Update #1

The NWS out of Sioux Falls has issued a Winter Weather Advisory for areas of northwest Iowa tonight through Thursday evening.

The counties of Lyon, Sioux and Plymouth are under this advisory from 10 pm tonight through 6 pm Thursday; Temperatures just above freezing will halt any freezing rain that was possible this morning, thus mostly rain falling this afternoon before temperatures begin to drop once again. This rain should change over to snow tonight, with heavy snow possible tomorrow morning, total accumulations at this time are forecasted to be 4-7 inches…
Other counties within the FSD warning area, including Osceola, Dickinson, O’Brien, Clay, Cherokee, Buena Vista and Ida are also under the winter weather advisory from 3 am Thursday until Midnight Thursday. Areas of freezing rain and snow should move into the area tonight, becoming all snow by Thursday morning where total snow accumulations should reach 2-4 inches. Some light ice accumulations are also possible before the snow changeover…
The rest of the state will likely be looking at mainly rain throughout this system, however counties nearby ones under the advisories will likely see a changeover to snow on Thursday as well, but only an inch or two seems likely at the moment.

Currently precipitation is rotating around this low that is centered in southwestern corner of Kansas and the Oklahoma panhandle. The low should move northeast into central Kansas this afternoon giving latest pressure falls over the plains. This is putting the deformation zone, or any area near the low that will be under nearly constant precipitation over most of the state of Nebraska as well as the mountains of Colorado. Other precipitation is moving north through eastern Kansas as well as Missouri, should begin to enter the state of Iowa this afternoon. Thunderstorms are possible in southern Iowa with this system, luckily most of this will fall as rain and not freezing rain like it was last night in areas of KS/OK/TX.

Only some light rain this morning here at my house, expecting more precipitation to slowly work its’ way into the area this afternoon and the main core of the storm to begin late tonight. Any slight shift in the path could affect the amounts of snow/ice, so although this current forecast looks good, don’t be surprised to here any changes this afternoon as the low continues to move.

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