Briefly:
Normal summer weather begins.
Friday update:
We saw three tornadoes touch down yesterday, and lots of big hail. Severe weather is shifting to the eastern Plains today. You should see a wall of large thunderstorms forming to your east this afternoon. We return to seasonal temperatures (mid to low 80s) with a slight chance of afternoon thunderstorms each day.
Update end of Friday.
Thursday update:
Yesterday was an active day. Longmont received, on average, another half-inch of rain (more on the south side). 8 tornadoes were reported in the state (updated figure 2).
All conditions remain for a repeat today, but the risk of more severe weather, including tornadoes, includes areas west of I-25 and up into the foothills (barely up to Estes Park including Red Feather Lakes, for example – updated Figure 3) . Like yesterday, stay alert this afternoon and evening.
Update end of Thursday.
Same day update:
Immediately after publishing today’s post, the Storm Prediction Center increased our severe weather risk Improved (3 on a scale of 1-5). There is a better chance of damaging large hail and tornadoes from west of I-25 into the eastern Plains (updated figure 1). Be aware of severe thunderstorms, tornadoes and warnings that will be issued this afternoon. I don’t post hours and warnings here (I’m not always online). Please use apps like Weatherbug and Storm Shield to be alerted!
End the same discussion of expectations.
Significant moisture is back, and the jet stream is set to help bring all flavors of severe weather near or along I-25 today and possibly Thursday as well (Figure 1). Storms should begin impacting the foothills and I-25 communities between 1-2 PM on both days. Rain chances remain high until around 10pm-12am
The hillsides are covered with a marginal risk (1 on a scale of 1-5) while I-25 people heading east have a slight chance (2 out of 5 – Figure 2). Hail, strong winds, and even a few tornadoes are possible near Longmont and Broomfield and to the north (Figure 3). Stay alert!
For Thursday, the slight risk pushes slightly west. Hail and strong winds are expected (Figure 4). At this time (Wednesday), there is no forecast for tornado chances, but that may be updated later tonight or tomorrow morning.
Rainfall east of the division may be very heavy in some areas as well. Figure 5 shows widespread totals in excess of 1 inch raising concerns of flooding as the area remains completely saturated due to the heavy rains seen so far this season.
Long-term outlook:
After these two days of excitement, we return to seasonal temperatures and little to no precipitation chances (Figure 1).
