7/4/05 TALK: Central/Southern High Plains

[Mark Farnik]

Happy Fourth of July everyone!
Well, there looks to be an interesting setup this afternoon and evening for the Central/Southern High Plains from the Nebraska Panhandle all the way down to around Lubbock, TX. This area is under Slight Risk. An excerpt from the SPC's 1300 UTC Day 1 Outlook:
...CNTRL HI PLNS TO OK/TX PANHANDLE REGION...
LOW LEVEL UPSLOPE FLOW SHOULD BECOME ESTABLISHED OVER THE CNTRL HI
PLNS LATER TODAY...IN RESPONSE TO BOTH DIURNAL HEATING OF THE MTNS
AND CONTINUED ESE MOTION OF WY/UT IMPULSE. ASSOCIATED INFLUX OF
BOUNDARY LAYER MOISTURE FROM THE LOWER PLAINS...AND LARGE SCALE
ASCENT ASSOCIATED WITH UPPER DISTURBANCE...SHOULD SUPPORT SCATTERED
TSTM DEVELOPMENT BY MID AFTERNOON OVER THE HIGHER TERRAIN OF S CNTRL
WY...CNTRL CO AND NRN NM.

COMBINATION OF INCREASING MOISTURE/UPSLOPE FLOW...STRONG HEATING AND
30-35 KT WNWLY MID LEVEL JET WILL PROMOTE SUPERCELL DEVELOPMENT AS
THE STORMS MOVE E/SE INTO THE PLAINS. LARGE HAIL AND POSSIBLY A
COUPLE TORNADOES APPEAR LIKELY. SUSTAINED MOISTURE INFLUX AND STEEP
MID LEVEL LAPSE RATES SUGGEST EVOLUTION INTO ONE OR TWO MCSS BY
EVENING. WHILE THESE SYSTEMS MAY MOVE E INTO WRN KS...THE STRONGEST
ACTIVITY MAY SPREAD SSE TOWARD THE OK/TX PANHANDLE REGION. THESE
CLUSTERS MAY POSE A RISK FOR WIND/HAIL INTO EARLY TUESDAY.

Currently the SPC has eastern Colorado outlined under 5% risk for tornadoes, which has me slightly concerned because of all the festivities today. They also have us hatched with 25% large hail probabilities.

The Denver AFD also reflects concern over the storms that could form later today:SHORT TERM...TODAY IS SHAPING UP TO BE MORE ACTIVE THAN YESTERDAY
CONCERNING BOTH COVERAGE AND SEVERITY OF STORMS. WE HAVE ALREADY
HAD ONE SEVERE STORM ROLL SOUTHEAST THROUGH JULESBURG OVERNIGHT
PRODUCING PENNY SIZED HAIL. LOW LEVEL MOISTURE WILL HAVE A BETTER
SHOT OF MOVING BACK INTO THE FORECAST AREA TODAY CONSIDERING
STRENGTH OF HIGH PRESSURE BUILDING ACROSS THE NORTHERN PLAINS AND
BETTER DAY 2 SCENARIO WITH EAST/SOUTHEAST FLOW POSSIBLY SETTING UP A
DENVER CYCLONE. LOW LEVEL DEWPOINTS BY MID AFTERNOON ARE EXPECTED
TO RANGE FROM THE MID 40S IN THE I-25 CORRIDOR TO THE MID 50S OVER
THE EASTERN PLAINS. THIS WOULD YIELD CAPES FROM 1000-1500 J/KG IN
THE FRONT RANGE METRO AREAS TO 2000-2500 J/KG OVER THE PLAINS.
SHEAR PROFILE WILL BE FAVORABLE FOR SUPERCELL DEVELOPMENT AS 0-6KM
SHEAR IS NEAR 20 M/S. THERE IS EVEN A RISK OF A COUPLE TORNADOES AS
LOW LEVEL SHEAR WILL BE BETTER THAN YESTERDAY...AND STORMS ARE
EXPECTED TO DEVELOP OVER THE TYPICAL CONVERGENCE ZONE SOUTH AND EAST
OF DENVER.

Dewpoints as of 8:00 a.m. are 56 at Akron, 51 at Greeley and 57 at Burlington, which is unusually high for the eastern plains of CO. There is a considerable dewpoint dropoff west of Greeley (only 41 at DIA; now that is a drastic difference in a short distance; I believe the term is a dewpoint depression. Correct me if I'm wrong, please, I am an amateur forecaster. ) These dewpoints almost always only occur when we are going to have a severe weather outbreak. Where I live(20 miles north of Fort Morgan) it terribly humid and low, moist gray stratus deck is beginning to break up already. With high's in the mid 80's and little if no capping present, there could be a few explosive, potentially tornadic supercells over much of eastern CO today, later forming a south/southeastward propogating MCS that will race towards southwestern KS and the OK/TX Panhandles with damaging winds, very heavy rains and large hail. I'm worried, to be frank. Why couldn't this have waited till tomorrow so all of us Colorado chasers could go after these potentially very impressive storms? :x Oh well, LOL. Feel free to post your comments on this developing situation. Everyone stay safe today and God Bless America! :!:

 

[Verne Carlson]

Looks like a good day for e. CO especially to the south/east of Denver.

Target: Byers, CO to start then south of Limon on HW71

I would look for storms building over the Palmer Ridge and then moving to the se into the better parameters near LaJunta - Lamar. The latest RUC has the best shear 30-40kts, helicity and cape along the Arkansas river basin.

I have a BBQ at my house today otherwise I would definately be out chasing today. I am hoping that tues and weds are just as good when I can get out after 3pm for some local action!

 

[Mark Farnik]

The SPC just posted their 1630 UTC Outlook...
The 5% tornado probabilities now cover an area from Guymon, OK to Scottsbluff, NE south to north and Aurora, CO to Goodland, KS west to east. The 25% hail probabilities area has also been enlarged with all of eastern CO hatched. Wind probabilities were upgraded from 15% in the 1300 UTC Outlook to 25% with a hatched area from Burlington, CO to Vega, TX. Dewpoint has actually risen one degree to 57 at Akron, dropped one to 50 at Greeley, risen one at Burlington to 58. In Cheyenne the dewpoint is at 54.4 and at Kimball it is 53.6 so there is plentiful low level moisture in Wyoming and Nebraska as well. Dewpoints are coming up considerably along the Front Range, with DIA at 48 and Jeffco Airport at 50, a considerable rise from the 41 and 39 they were just three hours ago. This shows that the low level moisture is advecting into the Front Range with this muggy southeast wind we have going. An interesting detail is that Monument Hill's dewpoint is only at 37 and Limon's is at 47. There seems to be a pocket of LOWER dewpoints along the Palmer Divide.
Strange. I've also noticed a faint boundary of sorts on visible satellite set up southwest to northeast from far northern Douglas County across western Araphahoe/Adams counties into Morgan County which might be a storm focus point later this afternoon. The latest Denver HWO mentions this boundary for the potential of a brief tornado. This evening I'm going to be at Brush at my grandparent's celebrating both the Fourth and my cousin Jared's birthday(His birthday is actually the 9th but we have always combined them together). I hope this won't be as nasty as it possibly could be... Combine one strong supercell with large hail/damaging winds/possible tornadoes and blissfully unaware 4th of July picnicers and you have a potential recipe for mayhem. :shock: I know it sounds like I'm being melodramatic and blowing this out of proportion but someone could really get hurt, especially with the threat of large damaging hail and fierce high winds, which could knock over the picnic tents and send plastic utensils, freestanding barbeque grills etc. flying.
Everyone that lives in eastern CO should be alert and aware this afternoon and evening. :!:

 

[Verne Carlson]

MD has just been issued for e. CO, s. WY, NE panhandle:

http://www.spc.noaa.gov/products/md/md1640.html

 

[Mark Farnik]

Looking at the wording of the MD, when they issue a watch it will most likely be a tornado watch. Looking at the latest boundary locations and dewpoint figures, I'm guessing on the watch area being from Cheyenne in the northwest to Cheyenne Wells in the southeast and from Colorado Springs in the southwest to Julesburg/Big Springs in the northeast. Possibly a second watch down in SE Colorado as well, probably later in the afternoon/early evening. It's all coming together folks. Looks probable that we will see Mother Nature's fireworks as well as the manmade ones tonight. I'm a little nervous about that boundary draped right across Morgan County. We'll wait and see.

 

[Joe Zemek]

There will be tornadoes today in E CO... because earlier I was hoping to be up there this weekend but am not

The RUC is for once totally messed up, failing to account for moisture in place and/or trying to scour it, but with what? E/NE flow across NE/KS is far from dry and convergence will enhance local Tds. Satellite loops show some weak boundaries in the upper corner of the state and into NE. My main concern would be whether RUC has it together on strengthening of wind fields later, but when you have upslope and upper 50s Tds in E CO, you chase.

Good luck to any heading out; I'll be photographing artificial fireworks instead.

 

[Tony Laubach]

I'm in the wrong place on the wrong day... again... but for good cause.. I'm visiting my Dad in Snyder, Texas today, but fortunately, do have some chance for storms, although not nearly as good as my resident state... story of my season...

I'm keeping an eye on things down in Texas just in case I can take my skeleton equipment bag and rental car out on a "local" trip between Lubbock and Abilene. Gotta stay out of the hail today, though... I didn't get the damage waiver on the rental!

 

[Tony Laubach]

Storms look to be firing along the boundry in Colorado right now. Few small cells going up just to the west and south of Limon.

As for me, I find myself in Snyder, Texas on the west side of a CU field which has developed over West-Central Texas. SPC put out an MD for the area from Northeast New Mexico stretching south and east into West-Central Texas. Hopefully storms can form a bit further to the west and move over my area at their peaks.

 

[Mark Farnik]

All right... here is the lowdown. As of 3:50 p.m. there are several severe warned cells in eastern CO. Currently the most intense is located in northeastern Lincoln/southern Washington/northwest Kit Carson counties moving east.
Other cells are in northern Weld county around Rockport/Carr/Grover heading southeast.
There is one cell of particular interest. It is developing only 25 miles southeast of me, just southwest of Brush. It seems to be rooted in the boundary that Denver has been talking about all day. It is rapidly intensifying and is currently stationary. This cell may be the one to watch.
From the SPC's 2000 UTC Outlook:
...CENTRAL AND SRN HIGH PLAINS...
THUNDERSTORMS HAVE BEGUN TO DEVELOP -- MAINLY INVOF THE HIGHER
TERRAIN -- ACROSS SERN WY / ERN CO / NERN NM ATTM...WITHIN SELY
UPSLOPE FLOW / FAIRLY MOIST POST-FRONTAL AIRMASS. STORMS SHOULD
INCREASE AS DESTABILIZATION CONTINUES...AND THEN SPREAD SEWD
OVERNIGHT AS MODEST SELY LOW-LEVEL JET DEVELOPS BENEATH MODERATE
NWLY FLOW ALOFT.

WITH SELYS INCREASING AT LOW LEVELS AND PERSISTENT NWLY FLOW
ALOFT...SHEAR WILL BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS.
THOUGH HAIL AND DAMAGING WINDS ARE EXPECTED WITH STRONGER CELLS THIS
AFTERNOON...INCREASING SHEAR WITH TIME SHOULD SUPPORT STRONGER STORM
ROTATION LATER THIS AFTERNOON / EVENING...WHEN SIGNIFICANT HAIL
AND/OR A COUPLE OF TORNADOES WILL BECOME MORE LIKELY.

I think if we can get a few discrete supercells that get rooted in these surface boundaries I think we have a fair shot at a few tornadoes in northeastern CO between 4 and 9 p.m. Leaving in about an hour for Brush for family party. Since my grandparents don't have internet I'll have to rely on my trusty weatherband radio for updates and my own two eyes to track the cells.
This could get very interesting very quickly. :shock:
Stay tuned.

 

[Edward Ballou]

Hey all, we're safely in Denver for the honeymoon. Just thought I'd drop in to say that we watched a cell RAPIDLY develop over Ft. Morgan. It was really awesome. Tony, I kept watch out for your tracer. That sucks that you can't be in the area. I think we just had thunder over head. We're a 15 minute walk from Coors Field. I wonder if they'll call the game tonight.

 

[Chris Allington]

Fairly intense cell now in Dawson County, NE...

core is up to around 70 dBz at times on the Hastings 88d, this cell seems to be basically following along a line just to the south of I-80...

 

[Mark Farnik]

All right, I'm going to leave for Brush now. Right in advance of a nasty looking cell bearing down on us from the northwest, as luck would have it. After looking at the radar, I'm taking our 1997 F-150. It already has hail dents from several previous storms. I'm not going to risk getting my pristine 44,600 mile 1995
F-150 beat up first thing. These cells are going nuts, they are popping everywhere. Stay safe everyone, and enjoy the fireworks if you don't get rained/hailed out tonight!" :!:

 

[Tony Laubach]

Log Lane Village just to the west of Fort Morgan is about to get hammered with some good-sized hail. Storm had a 70Dbz core on it a couple scans ago and will probably cover I-76 with 1 inch or larger hail as it passes over. Last scan shows a bow forming in this cell, which probably will also create some havoc on I-76 as it passes, probably blowing a few semis sideways.

Meanwhile in Texas, storms fired south of Big Springs but basically stay ovwer one area. Hard to chase in a rental cause I really have no place to go to get in the way and let it pass over me while I'm under a shelter. Not wanting to punch into the core to see what's falling out of it. Looks like its growing in size, though. No storms north of I-20 ATTM.