National Weather Service Weather Forecast Office

June 2008 finished up generally warmer and drier than normal. But that only tells part of the story. Cooler than normal temperatures in May, continued on into mid June. This kept the record snowpack melting at a mostly manageable level. Warmer temperatures during this period could have produced damaging floods. Most of the region received the majority of the monthly precipitation in the first cooler half of the month, especially on June 4-5. Though the summer season officially began on June 20^th, summer-like temperatures started a week earlier.

 

June 2008 began with a High Pressure ridge over the region in a dry southwest flow. Red Flag Warnings were in effect for northwest Colorado. At the same time flood warnings and advisories were in effect for many of the rivers in northwest Colorado, and the Green near Jensen. On the 2^nd, a weak disturbance passed across the north with a shallow cold front into northwest Colorado on the 3rd producing a few associated showers.

On the 4^th, a Pacific Northwest trough of Low pressure dug into Utah with 150 knot jet on its backside. This trough reached the Four Corners region by morning of the 5^th.

Snow advisories were issued for elevations above 9000 feet. Mountain snowfall reports ranged from 2-6 inches, with valley rainfall amounts ranging from nearly 1 inch at Vernal to 0.1” Durango. Cool morning temperatures on the 6^th helped decrease river flows, and produced some dense morning fog in Grand Junction along the Colorado river.

 

On the 7^th, a stationary cold front along I-70, sagged south in the evening. This produced scattered thunderstorms and rainshowers across the north-central mountains along with gusty southwest winds. These showers spread into the central-southern zones on the 8th.

 

On the 9^th, dry northwest flow aloft backed to west thru the day, then southwest overnight as the next Pacific Northwest Low worked inland. Red Flag Warnings and Wind Advisories for the valleys were issued on the 10th as the cold front worked through Utah then through Grand Junction by midnight. The morning of the 11^th, the cold front reached Four Corners. Four inches of new snow was reported Steamboat Lake. Mostly light showers were reported north of I-70, though Aspen reported light snow for a few morning hours. This storm system brought the coldest air of the month to the region, some 10-15 below normal. More importantly it also produced deadly tornados in eastern Nebraska and Kansas.

 

As the upper Low moved slowly across the upper Midwest on the 12^th, this region had cold morning low temperatures. Valley low temperatures in the 20s were reported in Craig, Meeker, Crested Butte, Gunnison, Ridgeway, Durango. Gusty northwest flow in the afternoon verified a Red Flag Warning for southwest Colorado. Afternoon temps more than 10 degrees below normal.

A weather pattern change began on the 13^th. An Omega Block set up over North America, with Low pressure systems along the west and east coasts, and a ridge over the Rockies. For the next two weeks, the forecast models consistently showed this blocking pattern breaking down on days 5 or 6. But this warm and dry pattern persisted into July.

Temperatures climbed to near normal on the 14^th, and nearly 10 degrees above normal on the 16^th and 17^th. This hot High pressure began to pull in some meager moisture. Dry thunderstorms began the afternoon of the 16^th. Flood advisories continued for the Colorado River near Cameo, Elk near Milner, White at Meeker, Crystal at Redstone, and Eagle at Gypsum. Added on the 17^th, was theYampa River near Steamboat Springs, and Roaring Fork near Glenwood Springs.

 

A weak disturbance passed across the north on the 18^th-19^th, with enhanced overnight thunderstorms. Northwest flow on its backside brought less-hot temps to the northern  and central zones, and no thunderstorms on the 19^th-21^st.

 

Another disturbance passed across the north on the 22^nd.  This brought warmer temperatures and increased mid-level moisture for scattered dry mainly-mountain thunderstorms.  Trace of rain was reported at Vernal and Aspen, a gust to 50 mph at Meeker. Areal Flood Advisories were added for southern Eagle county, Pitkin county, northern Gunnison county. Widely scattered late-day thunderstorms continued on the 23^rd-24^th, producing gusty winds but little rain.

 

Finally on the 25^th, due to a waning snowpack, most flood advisories were cancelled. The final Flood Advisory, for the Eagle River below Gypsum was cancelled on the 26th.

 

Subtropical moisture from the south began to work into the High pressure ridge for the final days of the month. On the 30^th, a Red Flag Warning was issued for southwest Colorado due to dry lightning.