Issue Date: Tuesday, May 23rd, 2017
Issue Time: 8:30AM MDT

— Flooding is NOT expected today

This morning’s visible satellite imagery shows a mostly clear start for nearly all of Colorado. The exception is a few bands of low/mid-level clouds across the Northeast Plains. This is actually associated with yet another disturbance that is rotating around the central United States trough that was described yesterday. Fortunately, today’s disturbance is significantly weaker than the past few days, and in fact will be weakening further throughout the day. In addition, the atmosphere is drier today with precipitable water values less than 0.5 inches statewide. While the aforementioned disturbance will graze mainly eastern Colorado with some light showers, partly to mostly sunny skies are expected for everyone else. Thus, no flood threat today.

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.

Zone-Specific Forecasts:

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

Mostly sunny this morning, then increasing clouds with isolated to scattered showers possible, mainly across eastern areas. Max 1-hour rain rates up to 0.2 inches. Flood is not expected today.

Primetime: 1PM to 6PM

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

Mostly sunny with warmer temperatures. An isolated rain/snow shower is possible in the Northern Mountains this afternoon, though less than 0.05 inches of precipitation is expected. Flooding is not expected today.

Primetime: 1PM to 5PM

Issue Date: Monday, May 22nd, 2017
Issue Time: 10:18AM MDT

— Flooding is NOT expected today

The impressive large-scale trough, centered over southwest Ontario this morning continues to rule the weather pattern in the Central Plains and Rocky Mountain states. The water vapor image, below, shows several disturbances (indicated by tan lines) rotating around the main low-pressure like spokes on a bicycle wheel. The southern disturbance is currently causing light to moderate rainfall in the Southeast Plains. In its wake, sunshine rules the land across central and northern Colorado.

The sunshine will be limited as clouds are streaming in from Wyoming. Looking ahead, it is this northern disturbance that will affect our weather this afternoon, evening and into the overnight hours. As it quickly moves south, it will cause mid-level lift, and scattered to numerous showers this afternoon and evening basically across the entire state (with perhaps slightly more coverage east of the Continental Divide). If this setup occurred later in the summertime, it could be conducive for a flood threat. However, today, moisture values are rather low with precipitable water values only in the 0.4-0.6 inch range. Thus, instability will be suppressed. Furthermore, storm motions will be swift, 35mph+, limiting rainfall in any given locale. Collectively, the best chances of a weak thunderstorm, and associated higher rainfall rates, will be in the Palmer Ridge and Southeast Plains. Even there, though, rainfall intensity will be light to moderate and a flood threat is not warranted.

A second impact of the large-scale trough is a cooler than normal atmosphere. This will promote more high-elevation snowfall. Later this evening, expect snow levels to fall below 8,000 feet once again.

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.

Zone-Specific Forecasts:

Raton Ridge, Southeast Mountains, Southeast Plains, Palmer Ridge:

Overcast with scattered showers this morning in the Southeast Plains. Expect brief clearing by early afternoon, followed by a second wave of showers and weak thunderstorms starting late this afternoon and into the overnight hours. Max 1-hour rain rates up to 0.7 inches. Max 24-hour rainfall up to 0.9 inches. Flooding is not expected today.

Primetime: 4PM to 1AM

Northeast Plains, Front Range, Urban Corridor:

Sunny early, then increasing clouds with scattered to numerous showers and perhaps a weak thunderstorm developing by early afternoon and lasting into the overnight hours. Max 1-hour rain rates of 0.5 inches per hour will be possible with max 24-hour rain amounts up to 0.75 inches. Snow level 9,000 feet lowering to 7,000 feet overnight. Flooding is not expected today.

Primetime: 2PM to 11PM

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

Sunny early then increasing clouds with scattered to numerous rain and snow showers starting in the north by early afternoon, then moving southward. Max 1-hour rain rates up to 0.4 inches, with max 24-hour rainfall up to 0.6 inches. Snow level 9,000 feet then lowering to 7,500 by late evening. Flooding is not expected today

Primetime: 1PM to 11PM

Issue Date: Sunday, May 21st, 2017
Issue Time: 9:15AM MDT

— Flooding is NOT expected today

A large-scale trough has setup over central North America, causing below normal temperatures for wide areas of the Central Plains and Rocky Mountain states including Colorado. As the water vapor image shows, below, another disturbance that is embedded within the trough’s circulation, currently over the Great Basin, is racing its way east/southeast. This disturbance will quickly cross Colorado today, providing at least isolated precipitation for many. The main impacts will be scattered rain showers (with snow showers above 9,500 feet) across most of western Colorado earlier in the day, spreading east by the mid-afternoon. Across the Palmer Ridge and Southeast Plains, weak instability will develop from the sun’s heating. This implies that weak thunderstorms could be embedded in the shower activity. However, storm motions will be 35 mph or higher, and moisture content is not high enough to support rainfall intensity capable of a flood threat. Thus, flooding is not expected today anywhere in the state.

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.

Zone-Specific Forecasts:

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

Scattered clouds early, then isolated to scattered showers and perhaps a weak thunderstorm developing by early afternoon and lasting into the overnight hours. Max 1-hour rain rates of 0.6 inches per hour will be possible in the Southeast Plains with lower rain rates elsewhere. Snow level 9,500 feet lowering to 7,500 feet overnight. Flooding is not expected today.

Primetime: 1PM to 7PM with showers continuing into the overnight hours

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

Partly to mostly cloudy skies with an increase in rain and snow showers by early afternoon. Coverage will be highest along and north of the I-70 corridor. Precipitation is expected to last into the late evening hours. Max 1-hour rain rates up to 0.3 inches with max 24-hour precipitation up to 0.5 inches. Snow level 9,000 feet lowering to 7,500 feet overnight. Flooding is not expected today.

Primetime: 1PM to 6PM

Issue Date: Saturday, May 20th, 2017
Issue Time: 9:40AM MDT

— Flooding is NOT expected today

This morning’s water vapor imagery, shown below (for the GOES-16 Band 10 which generally measures lower atmosphere conditions), indicates that the disturbance causing Thursday’s snowstorm continues to weaken and move out of Colorado. The last remaining impact from this feature will be some shower activity in the far northeast part of the state that will subside by late afternoon. Farther west, a pool of low-level moisture is being forced upslope, causing low clouds and scattered snow showers in the Northern and Central Mountains. In fact, if you look at the image closely, you can easily identify the Continental Divide as a moisture boundary! This activity will continue to subside through the day as drier air begins to mix in from the northwest.

For many higher-elevation areas, today’s theme will be melting snow. Temperatures are expected to rebound to just below seasonal normal, which along with the ample sunshine will boost the melt rates. At this time, we do not foresee any major flooding concerns as the melt-off is expected to proceed in a relatively orderly fashion. Thus, flooding is not expected today.

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.

Zone-Specific Forecasts:

Northeast Plains:

Mostly cloudy skies through mid-afternoon with isolated to scattered showers (and yes, possibly a snowflake mixed in) gradually ending. Max 1-hour rain rates up to 0.3 inches. Some clearing is possible late in the day. The South Platte River will continue to run high from Kersey through Sterling as the past storm’s flood crest moves through. Current analysis shows that river levels are staying on the lower side of forecasted values, and thus only isolated nuisance flooding of low-lying and poorly drained areas is expected. Thus, no flood threat for today.

Primetime: 11AM to 4PM

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

Mostly clear skies and much warmer temperatures today. Higher elevations of the Front Range and Urban Corridor will begin to see snow melt increase. While soils will be saturated, we do not expect flooding concerns as rivers and creeks continue to run below flood stage levels.

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

Mostly sunny except for higher elevations of the Northern and Central Mountains where isolated snow showers are possible through early afternoon. Warmer temperatures today, with substantial snow melt likely. However, flooding is not expected today.