In Brief:
More rain showers followed by daily afternoon storms. Welcome water!
Monday Update:
The waves of rain and thunderstorms (thankfully nothing became severe in Colorado with that storm) brought about 0.2" of water around Longmont and about a quarter to a third of an inch of rain to Boulder (Figure 2 update). Broomfield saw about 0.1 to 0.3 inch of water in spots (Figure 3 update).
Another wet system will begin drop rain along I-25 around 3pm Tuesday continuing to mid-morning Wednesday (Figure 4 update). The weatherunderground.com model brings about 0.6" of water with this system while the GFS leans on a heavier amount approaching an inch in many spots.
After that, we'll see some warmth return with wandering afternoon storms then an extended unsettled period next week. We will take all the moisture we can get!
End Monday update.
Sunday Update:
There is a Marginal Risk (1 on a scale of 1-5 where 5 is the highest threat) for severe weather associated with thunderstorms today across all of the state from an east-west line running through south Denver up to Wyoming. There is a 5% chance that damaging thunderstorm winds (>65mph) or damaging hail (>1inch in diameter - Figure 1 update) will occur within 25 miles of any particular spot/home in this upper half of the state (as issued by the SPC and the NWS).
Timing: Thunderstorms should start in the mountains around 10am and begin to impact the I-25 cities around 12-1pm. Storms and showers will continue on and off into the late evening hours and even towards Monday morning. The severe threat should diminish in the early evening.
Amounts: Most locations will receive 0.1-0.25 inch of water but some locations may approach a (fortunate) 0.5 to 1 inch of wonderful water.
End Sunday update.
Forecast Discussion:
We enjoyed three days of summer-like heat at the end of the week. Our next cold front sweeps the state midday on Sunday with storms and showers ahead and behind the front (Figure 1). This is driven by a relatively slow moving trough (red line Figure 2) and a low forming downwind of the Rockies in southeastern Colorado (Figure 3).
The thunderstorms that form with this system warrant a marginal risk for severe weather (1 on a scale of 1-5 where 5 is the highest risk - Figure 4). The primary risk is for a 5% chance of wind gusts over 65mph within 25 miles of any point in the shaded area - Figure 5).
The Longer Range Forecast:
Another trough rotates through the first trough bringing in another round of showers Tuesday to Wednesday (Figure 1). Over the next 5 days, we should see about 1/2 inch of water from Longmont to Broomfield (Figure 6). Warm weather returns on Thursday with afternoon thunderstorms giving a hint of summer 'monsoon' rainfall patterns.
