6/09/2010 FCST: CO/WY

[Adam Adkins]

Wednesday looks like a good setup from the Colorado Springs, CO to Cheyenne, WY area.

All models are showing CAPE values in excess of 3000 j/kg, with the NAM showing as much as 4500 j/kg over the northern palmer divide.

QPF looks healthy on both models but placement is an issue as the NAM has it over the palmer divide while the GFS has it mainly in Wyoming.

Bulk shear values look over 60kts with effective helicities over 300-400 max in central CO.

CAP looks pretty strong early, but upslope flow along and north of a developing warm front in central CO should help initiate supercells.

Definitely favorable for tornadic supercells in central CO!

 

[Andrew Stoller]

I learned my lesson with this pattern Monday! It was a death cap then, and looks to be tomorrow. You'll need to stay as far north as possible into east central WY where the jet stream is and where temps are cooler. Convection seems to fire off the Laramie range daily.

 

[Mike Hollingshead]

I learned my lesson with this pattern Monday! It was a death cap then, and looks to be tomorrow. You'll need to stay as far north as possible into east central WY where the jet stream is and where temps are cooler. Convection seems to fire off the Laramie range daily.

Yesterday had the 16c 700mb line running along I80 over towards North Platte...even warmer to the south of that. It also had pretty cool sfc temps relative to that in a lot of northern CO. Tomorrow via the 18z NAM is more like 10-11c at 700mb in the same area. It's all around much cooler than Monday was. I could see better heating and moisture this time as well. To me looks like a pretty solid setup from Denver to Cheyenne.

http://www.wxcaster2.com/CENTRAL_MESO-ETA_700_GPHTMPWINDRH_30HR.gif

Far more doable.

 

[Eric Bucsela]

Yesterday had the 16c 700mb line running along I80 over towards North Platte...even warmer to the south of that. It also had pretty cool sfc temps relative to that in a lot of northern CO. Tomorrow via the 18z NAM is more like 10-11c at 700mb in the same area. It's all around much cooler than Monday was. I could see better heating and moisture this time as well. To me looks like a pretty solid setup from Denver to Cheyenne.

Agreed. Just looking now at the 00z NAM, and CINH for Wed does look much lower than Monday, consistent with the lower 700mb temps. NAM simulated radar shows precip in east-central CO by 00z, with decent shear and moderate CAPES of 2000 to almost 3000 J/kg. I'm looking forward to a good chase day.

 

[Adam Adkins]

Well today seems very similar to last monday when a strong cap prevented any kind of thunderstorm activity over northeast Colorado. The GFS shows a strong cap that would likely prevent severe storms however the NAM shows a much weaker cap. The RUC is more in line with the NAM. I'm not sure how it will play out!

 

[Andrew Stoller]

Yea, the 12z NAM has much cooler 700 mb temps in ne CO, and it looks like the RUC is trending that way as well. One caveat today is extensive morning cloud cover except along the front range north of Denver. Southeast WY looks fairly socked in as well. I'd probably park along I25 somewhere north of Denver today and go from there.

:edit: RUC is still fairly capped across CO - has precip breaking out mostly in se WY. I'd target Cheyenne today.

 

[Adam Adkins]

It's hard to determine what will develop today. I sure hope it is not in Wyoming because it seems like every single setup this year has been so far north. The 12z WRF shows the CAP completely eroding across all of northeast Colorado and breaks out some healthy precip in the area - south of Wyoming. However, I would appreciate some more experienced forcasters opinions!

 

[Adam Adkins]

The CAP seems to be eroding fairly substantially around the Greeley area north. SBCAPE over 3000 and MLCAPE over 2000 plus 50+ bulk shear in the same area. Looks like a good setup around the Greeley area north to the border. Thoughts appreciated!

Edit: SPC has just issued a watch likely MD for the area from Denver to Cheyenne.