Issue Date: Saturday, June 24th, 2017
Issue Time: 9:20 AM MDT

NO FLOOD THREAT IS FORECAST TODAY.

Easterly, upslope flow east of the mountains has kept the low-levels fairly saturated east of the Continental Divide, resulting in widespread cloud cover this morning for those areas. As the day wears on, clouds will begin to mix out and daytime heating will play on this moisture, producing isolated showers/thunderstorms along and east of the Continental Divide. Any activity is expected to remain garden-variety, producing gusty winds (up to 40 mph) and periods of light-to-moderate rainfall. Moisture isn’t deep enough to warrant any flood threat considerations, but any heavy rain over poorly-drained areas may result in brief street/field ponding. The majority of the showers/thunderstorms that develop will do so over the Front Range, Southeast Mountains, and Palmer Ridge, moving east-southeastward with time over adjacent regions.

West of the Continental Divide, however, dry air is running the show resulting in nothing but sunshine. A few afternoon clouds will develop over the higher terrain, but mostly sunny skies will prevail. The one exception to the rule will be over the San Juan Mountains, where an isolated shower/weak thunderstorm or two is expected during the afternoon/evening hours, resulting in gusty winds, lightning, and light rainfall.

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:

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

Clouds will mix out a bit as the day wears on, resulting in partly sunny skies by this afternoon. Isolated showers/thunderstorms are expected to develop over the higher terrain of the Front Range and Southeast Mountains, as well as the preferred terrain of the Palmer Ridge. With time, the showers/storms will move east-southeastward over the adjacent regions. Maximum rain rates are as follows:

Front Range and Southeast Mountains: 0.3-0.7 inches/hour
Palmer Ridge, Raton Ridge, and Urban Corridor: 0.4-0.8 inches/hour
Northeast Plains and Southeast Plains: 0.6-1.2 inches/hour

Timing: 1 PM – 11 PM, with a few lingering showers/storms over the eastern plains and Raton Ridge into the early morning hours

Northern Mountains, Central Mountains, San Juan Mountains, and San Luis Valley:

A couple isolated showers/weak thunderstorms are expected over the higher terrain, eventually moving over the lower elevations to the south/southeast. The main impacts from any activity will be gusty winds, brief periods of light-to-moderate rainfall, and lightning. Maximum rain rates (0.3-0.6 inches/hour) will remain below flash flood thresholds, so no flood threat is warranted.

Timing: Noon – 11 PM

Southwest Slope, Northwest Slope, and Grand Valley:

Mostly sunny and dry conditions will be the name of the weather game today for these regions as high pressure and very little moisture remain settled over the area. A few cumulus clouds over the higher terrain will be about all Mother Nature can muster today.

Issue Date: Friday, June 23rd, 2017
Issue Time: 8:25AM MDT

— Flooding is NOT expected today

It is a tale of two weather patterns today, as easily seen in the visible satellite image, below. To the east of the Continental Divide, a stable air mass punctuated by a low cloud deck is firmly entrenched. Even with the high June sun, instability this afternoon will be slim to none as the clouds act as a barrier to insolation. To the west, clear skies are seen with temperatures cooling off to just above seasonal normal. A few showers will be likely mainly across southeast Colorado today. A week thunderstorm will be possible along the Sangre de Cristo mountains and northern San Luis Valley. However, flooding is NOT expected today.

With only limited rainfall expected, the Arkansas River below Pueblo Dam is expected to stay at current levels, just under Minor flood stage. Thus, the low flood threat has been removed there.

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:

Southeast Plains, Northeast Plains, Urban Corridor, Front Range, Palmer Ridge, San Luis Valley, Southeast Mountains:

Mostly cloudy and much cooler today with scattered showers and perhaps a weak thunderstorm possible especially over southern areas. Max 1-hour rainfall up to 0.5 inches. Flooding is not expected today.

Primetime: 11AM to 6PM

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

Mostly sunny and slightly cooler today. The gusty winds observed yesterday are expected to subside today, and the Red Flag warning has expired.

Issue Date: Thursday, June 22nd, 2017
Issue Time: 10:40AM MDT

— LOW flood threat for Northeast Plains, Urban Corridor, Front Range, Palmer Ridge, Southeast Plains
— LOW flood threat for the Arkansas River downstream of Lake Pueblo (Pueblo Dam)
— An afternoon forecast update may be issued today

A strong surface high pressure system will be moving across the Northern Rockies today, accompanying a southward moving cool front (see water vapor image below). The front is currently on the WY/CO border and will move across eastern Colorado throughout the day, stalling near the NM border later this evening. The front will bring about a significant drop in temperatures statewide, but especially east of the Continental Divide. Accompanying the drop in temperatures will be a period of time starting this afternoon through late this evening with a noticeable increase in low-level moisture.

With plenty of morning sunshine, the atmosphere will turn unstable later this morning and into the afternoon hours. Expect a round of shower and thunderstorm activity over northeast Colorado this afternoon, slightly after peak heating. Large hail up to 1.5 inches and gusty winds will be possible with these storms.

Things continue to stay interesting into the evening and early overnight hours as guidance is in good agreement that another surge of moist upslope flow will impinge on northeast Colorado. Isolated heavy rainfall will continue to be possible through the overnight hours as instability is maintained. In all, a Low flood threat has been posted for large parts of eastern Colorado.

Finally, the Arkansas River continues to run high below Canon City. Of particular concern is the stretch downstream of Lake Pueblo (Pueblo Dam) where high reservoir levels, and expectation of future snow-melt related inflows, are causing extra releases. Also exacerbating the threat is the potential additional precipitation this afternoon. A Low flood threat has been posted.

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:

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

Sunny early then partly to mostly cloudy and cooler with several rounds of showers and storms starting this afternoon, lasting into the overnight hours. Max 1-hour rain rates will be 1.2 inches closer to the foothills to 1.9 inches farther east. Large hail up to 1.5 inches and gusty winds could accompany the strongest cells. Heavy rainfall chances will persist into the overnight hours as moist upslope flow continues.

Primetime: 2PM to 3AM

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

Mostly sunny and slightly cooler today with isolated to showers and a weak thunderstorm possible especially for northern areas. Max 1-hr rainfall up to 0.4 inches. Flooding is not expected today. A Red Flag Warning is in effect for far western areas this afternoon. Dry lightning could also exacerbate the fire threat.

Primetime: 1PM to 8PM

Issue Date: Wednesday, June 21st, 2017
Issue Time: 11AM MDT

— LOW flood threat for Southeast Plains

Today’s low-level water vapor image, below, shows a rather disorganized picture with pockets of moisture noted underneath the strong Great Basin high pressure ridge. A strong jet stream was noted north of Colorado, supporting a surface low pressure across eastern Wyoming and into South Dakota. This will provide northeast Colorado with downsloping flow, contributing to one more day of intense heat. A secondary area of surface low pressure was noted in southeast Colorado. Very similar to yesterday, this will allow for a focal point for afternoon shower and storm activity in the far southeast part of the state. With plenty of instability expected, heavy rainfall will be a threat. Furthermore, parts of Baca County received over 1 inch of rain yesterday, implying that additional rainfall here will cause for enhanced runoff compared to dry soil. A Low flood threat has been posted for the region. Large hail, up to 1.75 inches, will also be a possibility.

Elsewhere, limited instability will support isolated to scattered storms across the northern half of the state. However, the instability profile and storm motion together suggest only light rainfall amounts. Gusty winds will also accompany the strong cells.

Riverine-wise, the Roaring Fork upstream of Aspen continues to recede though this is being mitigated by extra flow from closure of a diversion tunnel; flooding is not expected here. The Arkansas River is running at elevated levels upstream of La Junta. However, without additional precipitation, we do foresee a flood threat.

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.