Monday's Debrief - Yesterday we all knew what we were up against. It was a battle if any 'Real' cells would make the valleys due to the atrocious storm speed.
I watched the radar very closely all day and here's what happened. No cell was able to survive two volume scans of the radar. Two volume scans of the Doppler Radar is 10 minutes, no cell made it 10 minutes without dying. Why did they die, I'll remind you one more time. When there is not enough wind aloft, rain falls straight down through the cumulus clouds own updraft, this kills the cell. We need to have 12 to 14mph at a minimum for a storm speed, these higher speeds displace the rain away from the cumulus clouds updraft, then the cells make the valleys.
I have been trying real hard to convey this to everybody, storm speed is critical to us getting convective rain. So long story short, unfortunately things cooperated forecast-wise as we only had a few showers. We are not going to get much rain with a weak storm speed, what fell yesterday was very light.
Quick Forecasts for Today (Tuesday):
Aspen: Mixed clouds and sun. A few cells roaming around this afternoon/evening. High 84 Aspen, 88 Basalt. Wind NW 10 to 20mph with a few gusts, wind becoming S this evening. Low 48 to 52.
On-Mtn: Mixed clouds and sun. A few cells roaming around this afternoon/evening. High 72 at mid-slope, 66/67 near 11K. Wind NW 10 to 20mph with a few gusts, wind becoming SE this evening.
Today (Tuesday)...Updated 545am - So today our winds aloft are not as northerly as they have been. The slight bit of westerly flow aloft will allow for a touch of upper air support coming east from Utah. Our PM dewpoints probably still remain a little below August thresholds, our storm speed averages out at 10kt (12mph) which is right on the borderline. Vector analysis is OK, this means there are some patches of low level convergence but nothing that lasts a while. Instability is there but our CAPE values are average.
Summation, I will call our sky cover mixed clouds and sun overall along with some elevated smoke/haze. We have enough OK parameters that I will allow for a few cells roaming around this afternoon/evening, we probably don't have enough solid parameters that a widespread shower/storm event occurs. Long story short, some of us get a little rain and others do not. Indices for Today...UV Outlook a 6, Outdoor Index a 6, Thunderstorm chance 30 to 35%.
Wednesday (Updated 545am) - There is enough wind from the west in the mid-levels of the atmosphere that I cannot take the risk of some cells being around in the afternoon/evening. Our ambient water will remain below August thresholds but it's high enough that instability will cause radar echoes to form. Our storm speed is around 11kt (13mph) which is at the low end of thresholds. So it's a day where it's doubtful anything widespread happens but a few of us get lucky with a shower/storm.
Summation, I'll call the day mixed clouds and intervals of sun with temps in the lower 80s around Aspen, There will be a few cells roaming around in the PM and hopefully some of us get lucky. Indices for Wednesday...UV Outlook a 5, Outdoor Index a 6, Thunderstorm chance 30%.
Thursday (Updated 545am) - Basically I have to do the same thing for Thursday. We have enough moisture that some PM cells develop but nothing stands out as extra special. Guidance has a storm speed under 10kt and we all know that means a widespread shower/storm event will not happen. Expect temps in the lower to mid 80s around Aspen.
Extended (Fri-Sun 8/17-8/19) - The models have a westerly flow aloft on Friday and Saturday. Once again this is better than a N or NW flow. I will keep the risk of some PM action in the forecast both days. The flow goes back to NW on Sunday and I'll keep it dry. Temps should remain warm through the period with lower 80s most likely around Aspen.