This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.
Forecast Discussion:
The ridge still rules, the atmosphere is dry, there is no smoke in the state, and a cool down is visible - 8 days out from now.
Figure 1 shows the dry weather on this side of the stationary west coast trough (purple is center of moist axis). The surface map for later today shows dry conditions and high pressure over Colorado (Figure 2). The temperatures will continue to be about 10-13F above average (Figure 3). Toasty!
The longer range forecast:
Figure 4 is the animation of the upper air pattern showing Colorado sitting under the same pattern for most of the next week. You can see Florence drift in, die inland and zip off to the northeast on this run of the GFS. Finally, about 7 days out, you can see the ridge modify and break down. Troughs start to enter the West.
The first big cold front roars into the state the early morning of Thursday the 20th (Figure 5). That is a 30F drop from the week between now and then.
Looking at Florence, there is coverage of this storm everywhere now, and is often updated more frequently than this column as landfall is hours away. Figure 6 shows the push-me-pull-me of the two highs will now result in the storm drifting VERY slowly to the southwest for 48 hours or more before heading deep inland to die. Some folks in the Carolina's will see feet of rain. The tangle of models all pretty much agree. The pink arrow in Figure 7 is the approx. location of the earlier path. That is quite a southward drift!!
