Off To The Front Range

Here in north Tucson, the mornings have been very pleasant for walking this week, with light winds and temperatures down in mid-to-low 50s. Afternoon have continued dry, with temperatures in the 90s, and with some windy periods. There is some weather of interest up along the northern Colorado Front Range however.

Webcam view of Denver (above) this morning shows damp clouds and fog hanging over the city, while Ft. Collins (at bottom) is wet but not foggy. View at Ft. Collins is from the Atmospheric Science Department, looking north toward Cheyenne - both images grabbed from Jack Hales webcam wall.

The GEFS QPF plumes caught my eye yesterday and again this morning. The plumes of QPF above are from 06 UTC runs and are for KDEN, which is the international airport northeast of the city. The models forecast a very wet night tonight and day tomorrow - this in the short term but note that the range of amounts forecast is about 3.5 inches. The operational GFS is by far wetter than the ensembles - over 2.0 inches difference between the operational and the ensemble mean (blue vs black). 

The current grid point forecast for KDEN indicates 80% chance of showers and thunderstorms tonight and Saturday but there are no mentions of possible rain amounts. The Forecast Discussion product mentions that models are all over the place and that the office will have to monitor the rain situation closely next 48-hours, but there are no watches yet, except for up in the very high mountains for winter type weather. Very unusual to see such extreme variance among the GEFS forecasts at 12 to 36-hour time frames. The GEFS plumes for Greeley (below) are even more extreme than those for KDEN. I'll keep an eye on how all this evolves.