Under mostly clear skies a strong inversion developed overnight across Star Valley. Dramatic differences in temperatures were observed this morning. Etna ES dipped to 13 and Afton 12. However, in places like the forested areas of Star Valley Ranch and Salt River Summit, above the inversion, low temperatures this morning were as much as 20 degrees warmer, barely dipping below freezing.
Warmer air has spread across Star Valley above the inversion on Thanksgiving Day. Surface temperatures have risen into the 40s above the valley floor such as at Star Valley Ranch, even as clouds thicken ahead of the next Pacific storm. However, as of early afternoon Etna ES, below the inversion, has yet to reach freezing. The next system currently in the Pacific Northwest will move rapidly eastward bringing at least some snow across southeastern Idaho and western Wyoming beginning after midnight. There could be brief moderate snow as the cold front crosses the area late tonight and Friday morning. The speed of the system is expected to limit accumulations to no more than a couple inches in the Valley and somewhat greater amounts in the mountains, particularly the Tetons.
Rapid improvement will occur by Friday afternoon as high pressure takes over. This will lead to a dry weekend continuing into the middle of the coming work week. The storm track shifts well to the north assuring a quiet end to what has been a stormy November.
|Comparison of GFS and ECMWF 500 mb Tuesday afternoon 11/29/11|
While there are considerable differences in the model solutions Tuesday, both keep the storm track to the north of the Valley. However, by late Wednesday/Thursday the ECMWF(European Model) suggests a return to stormy conditions while the GFS(Globel Model) keep the Valley high and dry.
|Comparison of GFS and ECMWF 500 mb Wednesday afternoon 11/30/11|