Howdy everyone,
Well, here is the vital stats for my stomping grounds, the High Plains of Eastern Colorado.
Chase season: April 30 - September 20
What to expect: Colorado's eastern plains usually experiences it's first severe weather around the 30th of April. (Though this year it came early- on April 20 an HP supercell developed just north of the Palmer Divide and raced east/northeast, dropping hail ranging in size from golfball size near DIA to grapefruit size near Otis, in Washington County and Yuma, in Yuma County. All this after NE Colorado spent most of the day socked in under a stratus deck; the warmest temperature in this part of the state was only 62 degrees at Burlington; it got chillier farther north.That's Colorado for ya!)
Our first true severe weather outbreak usually is waiting in the wings and happens about May 10-20. A good example of this is May 17, 2000, when over 22 tornadoes dropped from HP supercells rotating around a deep lee side low that formed directly overhead. The first severe storms hit just before 11 a.m. and continued until about 7 p.m. that night. One of those tornadoes passed directly over my farm, but that's another story for another topic. (Hmmm...) June is our best severe weather month, with classic and LP supercells in abundance. We usually have severe weather about 20 to 25 days out of the month in a normal year. Colorado's strongest tornado in recent history struck the city of Limon on June 6, 1990, almost 15 years ago. It carved a half mile wide path of destruction through the downtown buisness district as well as the northern residential area of that town. It was an F4, and it was thanks to our improved warning system that no one died in that storm and only twenty or so were injured.
Once we hit July and August, we hit monsoon season, when thunderstorms are almost a daily occurrence in a normal year and are often slow moving (thanks to sluggish winds aloft during that time of the summer) HP supercells that can create severe flash floods (July 31, 1976 Big Thompson Canyon Flood; July 28, 1997 Fort Collins Flood; and July 29, 1997 Pawnee Creek Flood) and very large and destructive hailstorms (July 11, 1990, "7-11" Estes Park to Colorado Springs- over $625 million in damage from golf ball to baseball size hail that fell for a long period of time; many of my fellow CO chasers that live in the Metro Area probably remember that one well!) However, July storms can also be tornadic (July 5, 2000, beautiful classic supercell dropped a multiple vortex F3 just after dark, a mile or so north of Dailey in eastern Logan County (east of Sterling, for those who are not familiar with the area) that obliterated 5 farms and caused well over $1 million in damage; July 21, 2000, "wedding cake" LP drops highly visible F2 over eastern Weld County, near Masters, which was on the ground for over a half hour and was well documented by news choppers and chasers alike.) Our severe weather season generally winds down by September 10, though we can still have nasty storms after that, just not very frequently.
Time of day: Though they can form as early as 11 a.m., most storms here hold off until about 1 or 2 p.m. Best time to chase is 1 to 9 p.m.
Cell movement: In April, May and June, cells usually move in the typical east/northeast direction. However, in July, August and September, storm motion is usually from northwest to southeast.
Storm formation points: Storms usually develop in one of three places around NE Colorado: A) The Cheyenne Ridge B) The Palmer Divide or C) The Foothills.
Road network: I will be discussing the roads east of I-25 and north of I-70, which is my territory. We have a pretty consistent road network in northeastern Colorado, with roads pretty much following the set N-S/E-W pattern. One place to avoid is northeastern Weld County (the Pawnee Grasslands) north and east of Briggsdale; it is very easy to get lost in that couple hundred square miles if you don't know the area. A rule of thumb is that these roads often defy what they are shown as in the DeLorme atlas. The roads are very curvy and pass through lots of steep draws and creek bottoms. Flash flooding is common, especially in July and August, and you ABSOLUTELY DO NOT WANT TO GET CAUGHT UP THERE IN AN HP STORM AT NIGHT! That happened to me and my dad once and it was SCARY AS HELL! Otherwise, the county roads are fine.
There are three east/west highways north of I-70: Highway 14 (northernmost option; runs from Fort Collins to Sterling, passing through Ault, Briggsdale, New Raymer and Stoneham along the way), 34(middle option; our section starts at at Loveland and runs slightly south of east through Greeley, Fort Morgan,Brush, Akron, Yuma and Wray on into Nebraska; and 36 (the southernmost option, which begins at Byers and shoots east to Last Chance, Anton, Cope and Idalia before it jogs north 3 miles and turns back east, entering Kansas.)
There are a total of 6 north/south options. They are: Highway 79, which is farthest west; it runs for only 22 miles from Bennett to Prospect Valley.
Then there is Highway 52, a weird highway;the first section runs east from Boulder, through Dacono, Fort Lupton, Hudson, and Prospect Valley before it makes a right angle north in southwestern Morgan County and ends at Wiggins. The second section (which I am very, very familiar with as I drive it every day from mid August-late May to and from school and every Sunday to and from church) is Main Street in Fort Morgan, then heads north out of town, under the Interstate and over the South Platte river, heading north for twenty five miles. It has essentially NO SHOULDER whatsoever and has lots of curves as it goes through the Wildcat Creek valley. It is not a fun road to drive on a daily basis, but should suffice if you need to intercept at New Raymer.
The third road is Highway 71, which in it's entirety runs from southwest of La Junta all the way to the Black Hills, where it terminates at Hot Springs, South Dakota. However I will focus on my section of the road, which is from Limon to the Nebraska border south of Kimball. For the most part, this is a very desolate road; it only goes through four towns: Snyder (about 150 people) Brush (population 6,000 or so) Last Chance (nothing more than a crossroads) and Limon (just a little over 2,000 souls). If chasing south from Brush, make sure you fill up because there is NO GAS for 76 miles. If chasing north from there, do the same because it is something like 89 miles between Brush and Kimball, again with no service.
The fourth is a nasty piece of work called Highway 63; it runs south from Atwood through Akron and ends at Anton. Avoid this road at ALL COSTS; the state has not maintained this road and hasn't repaved it since the 1970's. Nothing but 53 miles of suspension-wrecking pavement. We had to bring a combine we had bought down this highway a few years back and one of those monster potholes damaged the axle badly :evil: Highway 61 is a pretty decent road: it is only 42 miles long, running from Sterling to Otis. It is in pretty good shape and is good if you need to drop south from Sterling or north from Otis to intercept.
Highway 59 is much like 71; long and lonely. It goes from Eads all the way to Sedgwick, however I will discuss the section I am familiar with, which crosses under I-70 at Seibert and heads north to Sedgwick. From Seibert, it is 26 miles to the interseciton with 36; it then jogs east 6 miles and resumes its northerly course just west of Joes. From there, it is 33 miles to Yuma (population 3,285). From there, it is 37 more miles to Haxtun, then yet another 24 to Sedgwick. It is a good option.
The final and easternmost north/south option is U.S. Highway 385, which probably rings a bell for all who have chased in the Texas Panhandle. That is because this is probably the longest north/south road in this part of the country: it runs all the way from Big Bend National Park to Rapid City, South Dakota, then becomes 85 and goes clear to the Canadian Border! Again, my focus is on the northeast Colorado section, which runs from Burlington to Julesburg. From Burlington (population 3,678) it is 56 miles to Wray (population 2,187) and then 37 miles to Holyoke (population 2,261). From there, the last leg of the Colorado section of 385 is 30 miles long, passing through Julesburg (population 1,467) and into Nebraska. Whew, that was a lot of writing! I hope anyone who wants to chase here finds this useful. Maybe I should write a guide for chasers to the highways of northeastern CO...
Visibility: Visibility is excellent for the most part. Only things that might hamper visibility is occasional hills/ridges. Best visibility is east of Akron, where the land is much flatter (west of Akron the land becomes more transistional between plains and foothills, i.e. more low hills, canyons etc.)
though it is still very good out here where I live. Right around and north of Wray there are a lot of sandhills, which cut down on visibility to some extent so watch out for that.
Distance to Tornado Alley: Right on the western edge of it, baby!
Non-Weather Photo Ops: The Pawnee Buttes and surrounding chalk bluffs in northeastern Weld County are awesome. Area around Wray is also scenic. Lots of abandoned farms/barns for those who are into photographing those. Also, there are tons of windmills around here; they make cool subjects for sunrise/sunset shots!
The mountains are only a hundred miles away; on clear days you can see them very well! A kind of prairie photographer's mecca, if you will! I know I love it! 8) 8)
