05/23/05 FCST: High Plains

[Verne Carlson]

0Z Eta is showing mucapes of 3000 and very high theta-e values for monday afternoon over eastern CO. With SE surface winds under WNW upper level winds it could be an exciting chase day in E CO.

 

[tom hanlon]

Well I believe that Monday has as good of chances as any other day this month.

SPC is predicting more of a MCS type event into NE as the eveneing arrives, so a very tentative target of Wray CO or basically the Border of CO/NE North of I70.

I had to read between the lines of the CO AFD to find this one ray of hope.

"THE POTENTIAL INSTABILITY IS BETTER ON MONDAY. THE QPF GRIDS
INDICATED SOME RAINFALL BOTH AFTERNOONS."

From the Goodland KS HWO

"THERE WILL BE A CHANCE OF THUNDERSTORMS EACH DAY FROM MONDAY
AFTERNOON THROUGH WEDNESDAY NIGHT. THERE IS POTENTIAL FOR SOME OF
THESE STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. "

From the North Platte NE AFD.

"ON MON...SE WINDS IN THE LOWER LEVELS
WILL ADVECT SOME MOISTURE...ALTHOUGH NOT A SIGNIFICANT AMOUNT. IN
THE WEST...DRYLINE BULGE PRESSES INTO THE PANHANDLE AND WESTERN
ZONES. THIS LOOKS TO PROVIDE A ROUND OF ISOLATED TSRA THAT WOULD
PUSH TO THE ESE THEN WEAKEN AS THE SUN GOES DOWN."

All in all the local forecast offices are not too positive about the chance of severe. The SPC however is fairly strong, well stronger anyhow, on the chances of severe. I wonder if sparsely populated areas are less aggressively warned or monitored ? After all a severe event in Yuma County CO is not likely to do much damage compared to an event along the Missouri River.

Target, Yuma and Phillips County Colorado. Hoping for some "upslope magic" and I admit a touch of wishcasting exist in this post.

--
Tom Hanlon

 

[tom hanlon]

Sitting in the North Platte NE Motel 6.

The DOW trucks and the Tornado Intercept Vehicle are parked next door. They are also hoping for something off the high plains of CO.

Goodland KS HWO..
" VERY LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOS WILL BE POSSIBLE WITH THESE STORMS. "

Might move the target a little south to Mid CO on the KS border. Southern Storm Movement as the main reason.

 

[Bill Hark]

I am in Goodland, Kansas. The forecast tomorrow is interesting with a slim chance of supercells and tormadoes. Pluses include backed winds and ample moisture. There is fairly good upper level support though according to the ETA, the higher 500 mb winds and helicities are to the north of Goodland into the Nebraska Panhandle. This is somewhat away from the better dewpoints. The May 23 00Z ETA shows precip breaking out across eastern Colorado, then spreading into Nebraska and Kansas by 0600 May 24. I am not sure how the models handle the effect of the increase in elevation and lifting. Right now, I'm thinking the Burlington to Yuma areas. After busting terribly yesterday in SE South Dakota, I'm hoping there will finally be storms.

Bill Hark

 

[Bob Schafer]

First I wasn't going to chase Monday, then I was, now I'm not.

I was impressed by the helicities progged 12 hours ago (in SE CO, NE NM) but they went away. The lack of 700mb and 500mb winds, mostly, and some possible cap issues are big concerns.

I predict junk down there in the form of your basic summertime garbage, and high based stuff up N of there.

Bob

 

[Bill Hark]

I am still hopeful for today but more concerned about the cap. Upper levels show 30 of NW flow at the 500mb level across the NE colorado, NW Kanas and Nebraska Panhandle. There is good flow at the 250 level but it rapidly drops of as one moves south from the South Dakota border. The 700 MB chart in concerning. The 10 degree line peaks over the area, almost reaching the Montana border.
http://www.rap.ucar.edu/weather/upper/upaCNTR_700.gif This should shift southward if you believe the RUC.
I am hoping the combination of instability and orographic lifting can overcome this. Dewpoints are improving with narrow area of 60+ in south eastern Colorado. Limon is already 58 with SE winds. The better dynamics and helicities are northward according to the RUC. As a compromise, I would still stay with Yuma, maybe now northward to Brush. I think Yuma is a big data hole. I have time to stay in Goodland and check more data.

Bill Hark
http://www.harkphoto.com

 

[Tony Laubach]

Hey gang! Good morning! Ready for a fun day in Colorado today! Looks like it'll be a doozy! Here's my morning analysis brought to you in part by the Mellow Yellow I smuggled out of Central Nebraska last week!

RUC ANALYSIS
Upslope, good CAPE, decent SRH; sturdy cap, but breakable. RUC shows very good parameters setting up across Eastern Colorado. CAPE values shows awesome amounts for our altitude with values over 2000 over most of Eastern Colorado by 0z. Worth noting that at 21z, there's a value progged at 3581 just to the southwest of Burlington! How's that for crazy! Higher values shift eastward from 21z to 0z, but more than enough for storms back west to fire and then move into higher values. Helicity values dot various areas along the foothills. Its strange, but they look as if they're centered near Ft. Collins, Denver, Colorado Springs, and Pueblo; not sure why those bullseyes are arranged that way, but they are according to the RUC. Values in these bullseyes range from 200 to 500 at 21z and down to 150 to 350 at 0z. A capping issue may create some problems at some point, however the RUC shows no cap at 21z over the Front Range and by 0z, shifts it to points east. 700mb temps are a bit higher than I'd like to see with values in the low teens across all of Eastern Colorado, but high temps today combined with the moisture we're suppose to see should be enough to overcome the cap. We couldn't ask for better moisture up here with values in the 50s and 60s! Thetea-E values look reasonable, and decrease through 700mb, so that's looking good, too. The RUC breaks out precip west of I-25 at 21z then fills an east/west band from Denver to about Yuma between the interstates.

15z SFC analysis shows low 60s dewpoints in Southeastern Colorado and mid to upper 50s east of Denver! Wow (for us)! Southeasterly winds will stream moisture in throughout the day today and keep us in an upslope pattern. We should do well today.

The ETA isn't so optomistic with those values, but I'm having a hard time believing models much these days anyway. This is Colorado; when this setup brings itself about, you chase.. PERIOD!

A target for today, I would says south of Akron wouldn't be bad, however you're in a data hole with no real chance for Wifi access. However, there is a library in Akron if you wanna old school it. Its at 302 Main Ave and should be open through the early evening hours.

Today looks like it'll play out further east with tomorrow likely being the better of the two days for Eastern Colorado. I'd be content with both setups, to be perfectly honest, and there's nothing that would keep me sitting at home for today's. I'm a bit concerned as NWS Denver has really played this setup down, not making mention in AFDs or HWOs even as SPC has thrown all sorts of odds over Eastern Colorado. I'm not sure why there is discrepency in this, but I guess they're making it so we have to make our own decisions! However, I am pretty confident that the best shows will happen east of a Buckingham/Roggen/Byers line, probably closer to I-76 as opposed to I-70 with better dynamics further north and the chance that storms will last well after dark up there.

Jon V and I should be on the road by noon up along I-76, likely stopping in Fort Morgan for data and maybe a southward adjustment in either direction from there.

Good luck to all out there today and I hope we see you all out there!

 

[Joe Zemek]

Tony, just homecasting here, but I wonder about the LL shear today. One line in the SPC Day 1 states that wind fields will be relatively weak, & I kinda see that in the NAM. Perhaps that's why the Denver NWS is holding off for now. I don't see a Denver Cyclone developing today, though if it does, wow is the moisture gonna be there. 500mb winds aren't really favorable to move a storm along the Palmer Divide. W/o that I'm not sure where my target would be, except that it would be at an intersection of two good roads.

At any rate, I agree, tho; gotta chase on a day like today in E CO and hope it pans out. CO does things that break conventional rules, that's for sure. Good luck!