STP 09-25-2016: Pockets of Leftover Rain and Snow Showers, Otherwise Dry

Issue Date: Sunday, September 25th, 2016
Issue Time: 8:58AM MDT

Summary:

With the strong trough overhead and a remaining fetch of moist west-northwest upslope flow, parts of the Central and Northern Mountains received steady rain and snow showers on Saturday. In particular, the Park, Gore and Sawatch ranges, as well as the Flat Tops tend to do well (if you like snow, that is) during west-northwest flow events. With it still being September, temperatures were warm and snow-levels fluctuated between 9,000 and 10,500 feet. Impressively, the Tower SNOTEL site received 1.0 inch of liquid equivalent, corresponding to 5 inches of snowfall. During the winter, the same 1 inch of liquid could produce up to 25 inches of snow, so the seasons do make a big difference. Below 9,000 feet, light rain or a rain/snow mix resulted in up to 0.5 inches of total precipitation by this morning.

Farther east, a dry and cool fall day was observed with temperatures running a few degrees below normal. Gusty winds in the morning eventually subsided leading to an excellent opportunity to enjoy the outdoors.

No official flooding reports were received on Saturday. For rainfall estimates specific to your area, check out our Storm Total Precipitation map below.

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Storm Total Precip Legend

FTB 09-25-2016: Dry and Cool Sunday

Issue Date: Sunday, September 25th, 2016
Issue Time: 9:00AM MDT

— Flooding is NOT expected today

As the water vapor image, below, shows the trough that has been in our weather discussion for about a week has moved east of Colorado. Interestingly and somewhat unexpectedly, a part of the disturbance broke off and is now spinning by itself near Baja California. This may increase subtropical moisture across the Southwest US in the coming days, but is not a factor today. Instead, Colorado will begin to be influenced by the rather strong ridge centered just west of California. This will promote downward motion and aside from a few boundary layer clouds today, it will be sunny across the state. In the low-levels, cool northerly flow will ensure at least one more day of slightly below normal temperatures. Neither precipitation nor flooding is expected today.wv_markup

 

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, scroll below the map.

 

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Flood Threat Legend

Zone-Specific Forecasts:

All Zones:

Mostly sunny early then partly cloudy and continued cool. High temperatures will continue to hover at or slightly below seasonal normal.

STP 09-24-2016: A Taste Of All Flavors on Friday

Issue Date: Saturday, September 24th, 2016
Issue Time: 8:58AM MDT

Summary:

Friday’s weather was very Colorado-like courtesy of a strong upper-level trough that finally entered the state during the late afternoon. So what do I mean by “Colorado-like”? Well, high temperatures soared above 90F in the Arkansas River valley as strong southerly flow and sunshine worked in tandem. There were scattered thunderstorms, albeit weak, mainly in the Northeast Plains. These raced northward with storm motions up to 50mph, and as you can guess, did not have any time to produce heavy rainfall. Nonetheless, a relatively impressive 0.5 – 0.75 inches did result from the strongest cells. Farther west, light to moderate rain showers with rainfall accumulations up to 0.75 inches eventually turned to snow showers above about 9,500 feet (though a non-accumulating rain/snow mix likely made it to lower elevations). Pictures and measurements from the Grand Mesa show over 3 inches of snowfall. Similar amounts were reported in the San Juans with Crested Butte officially notching 3.5 inches as of this morning; the Front Range higher peaks also got in on the action. Finally, gusty winds were found across the state, but especially east of the Continental Divide. Official reports of winds show gusts up to 70 mph across the Southeast Plains that were not associated with thunderstorm activity. Fortunately, no significant damage was reported although the winds certainly blew around patio furniture, trash cans and broke small tree limbs as evidenced through social media posts this morning. Finally, to top it all off, by far the coldest temperatures of the young fall season were observed this morning for many locations. For example, Pikes Peak bottomed out at 12.1F this morning with a wind chill of about -15F. All in all, a very Colorado-like Friday!

No official flooding reports were received on Friday. For rainfall estimates specific to your area, check out our Storm Total Precipitation map below.

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Storm Total Precip Legend

FTB 09-24-2016: Much Cooler With Leftover Rain/Snow For Some; Otherwise Dry

Issue Date: Saturday, September 24th, 2016
Issue Time: 8:50AM MDT

— Flooding is NOT expected today

The strong upper-level trough finally entered Colorado overnight, bringing a slew of changes for many and unofficially signaling the start of fall. In terms of the today’s flood threat, this morning’s precipitable water (PW) chart, below, shows all one needs to know. Moisture, both mid and low-level, has plummeted statewide with PWs at all five stations that we typically use reading below 0.5 inches. Despite the presence of some dynamics overhead, without moisture there will be no threat of heavy rainfall today. Otherwise, expect windy conditions to slowly subside by late afternoon. Ongoing rain and high-elevation snow showers are expected to continue across the Northern Mountains, Central Mountains and Northwest Slope making it feel like winter. For every else, enjoy the first true taste of fall!

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Today’s Flood Threat Map

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, scroll below the map.

nofloodthreat
Flood Threat Legend

Zone-Specific Forecasts:

Southeast Plains, Northeast Plains, Palmer Ridge, Raton Ridge, Front Range, Urban Corridor, Southeast Mountains:

Mostly sunny and much cooler with gusty morning winds (especially over higher terrain) gradually subsiding by mid-afternoon. High temperatures will be up to 20F cooler than on Friday. A few isolated rain and snow showers will be possible in the higher elevations of the Front Range. Max 1-hr rainfall rates up to 0.15 inches.

San Juan Mountains, Southwest Slope, Grand Valley, Central Mountains, San Luis Valley, Northwest Slope, Northern Mountains:

Mostly cloudy skies with scattered rain and snow showers continuing through the day. Max 1-hr rain rates up to 0.3 inches possible, with max 24-hour precipitation totals up to 0.7 inches in favored west-facing locations of the Northern Mountains, Northwest Slope and Central Mountains. Morning snow level is around 9,000 feet and this will climb to about 10,000-10,500 feet through the day. Up to 7 inches of snowfall will be possible in the very highest elevations.