Issue Date: Saturday, June 12th, 2021
Issue Time: 8:45AM MDT

— Flooding is NOT expected today

The building High pressure (south) means that temperatures will be on the rise today. With the increasing heights and the same dry air mass as yesterday in place, the majority of the state will be rain-free again this afternoon and evening. Best chance for an isolated storm or two will be over the Raton Ridge and far southeast corner of the state. Higher surface dew points exist behind yesterday’s front in the area outlined in green below. A surface High over Nebraska and South Dakota will help reinforce southwesterly flow across this region, which should pull some of this surface moisture back across the border. The initial threat from the stronger storms that develop will be hail and brief heavy rainfall, but the dry mid-levels will likely change this threat to wind fairly quickly. The dry air aloft will also help to limit rainfall rates in the small storm cores. Thus, there is no flood threat issued.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.

Zone-Specific Forecasts:

Southeast Plains & Raton Ridge:

A couple isolated storms may develop over the Raton Ridge this afternoon. As they drift east/southeast around the High, they will likely strengthen as they move into an area of higher dew points. Dry mid-levels will likely limit rainfall rates despite some higher dew points in the area. Max 1-hour rain rates up to 0.75 inches may be possible. The main threat from the storms will be hail and strong outflow winds. Flooding is NOT forecast.

Primetime: 2:30PM to 11PM

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

Dry day ahead and warming up this afternoon. Highs are forecast to reach into the upper 80Fs and low 90Fs over the I-25 Corridor and eastern plains. With increasing heights and low moisture availability (PW at 0.38 inches in Denver), rainfall is not forecast. Outside of scattered cumulus this afternoon over the mountains and ridges, expect clear conditions.

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

Temperatures will be on the upswing this afternoon with scattered cumulus clouds forecast to develop over the mountains (south). Highs could reach the mid 90Fs over the lower elevations with mid to upper 80Fs for the mountain valleys. Smoke will likely continue to limit visibility and affect air quality, although the near surface smoke looks to mix out by early afternoon. Rainfall is not forecast today.

Issue Date: Friday, June 11th, 2021
Issue Time: 8:30AM MDT

— Flooding is NOT expected today

It’s a “severe clear” morning across Colorado, our first in quite a while. A cool front passed across the state over the past 12-24 hours resulting in a ~10-15F reduction in high temperatures this afternoon in eastern Colorado. But more noticeable will be the significant reduction in humidity east of the Continental Divide. As shown below, dewpoint temperatures over parts of eastern Colorado have dropped up to 50F over the past 24 hours! Needless to say, it will be difficult to generate clouds today, much less precipitation. Thus, flooding is NOT expected.

The dry, windy conditions yesterday resulted in a couple of new wildfires. Some smoke will continue to be advected into Colorado from Utah, so keep an eye on air quality alerts from the National Weather Service.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.

Zone-Specific Forecasts:

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

Mostly sunny and seasonably warm today and not as windy. Some smoke drifting in from Utah has resulted in an Air Quality Alert over the Grand Valley. Stay tuned to the Grand Junction National Weather Service for updates. Flooding is NOT expected today.

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

Much cooler and drier today with mostly sunny weather. Flooding is NOT expected today.

Issue Date: Thursday, June 10th, 2021
Issue Time: 9:00AM MDT

— Flooding is NOT expected today

Today will mark the culmination of the recent early summer heat wave, with temperatures as much as 15F above normal especially east of the Continental Divide. As shown in the visible satellite image below, although the ridge responsible for the heat wave has moved slightly south and east, a warm air mass still remains over Colorado. A quickly approaching shortwave to the west will drag a strong cool front, by summer standards, across Colorado this afternoon and evening. However, before that happens, strong downsloping flow will cause a spike in afternoon temperatures east of the Continental Divide with near record highs in sight. West of the Continental Divide, the cool front passage will temper the heat to near seasonal normal level.

In terms of precipitation chances, we expect the vast majority of the state to be rain-free today. The only exception will be the far northeast corner of the state. There, very high moisture (morning dewpoints are in the low 70s F in parts of the South Platte valley – incredibly high for Colorado) should provide enough instability to spark a few thunderstorms during the cold front passage overnight. However, with 35+ mph west/northwest steering flow, only short-term heavy rainfall is expected. Large hail and gusty winds will likely accompany the stronger cells during the cool front passage.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.

Zone-Specific Forecasts:

Northeast Plains:

Hot and humid today but staying mostly dry. A cool front passage will trigger isolated to scattered thunderstorms overnight along the KS/NE border. Max 1-hour rainfall up to 1.3 inches will be possible, along with large hail and very gusty winds. However, flooding is NOT expected today.

Primetime: 12AM through 4AM

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

Very hot and dry today with near record heat possible. Flooding is NOT expected today.

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

Cooler, dry and very windy today, especially in the northwest. Red flag warnings have been posted for parts of the region mainly for critically low relative humidity especially during the early afternoon before a cool front passes through the region. Flooding is NOT expected today.

Issue Date: Wednesday, June 9th, 2021
Issue Time: 8:45AM MDT

— Flooding is NOT expected today

There is a lot of fog and cloud cover over the eastern plains to start the day, which is being generated from higher levels of moisture partially associated with the PM storms from yesterday. If you look closely, you can see the North and South Platte River valleys carved out. This cloud cover will likely linger through about midday before it burns off, but that could help to keep high temperatures 5-10F cooler this afternoon over the area. PW values will remain low today with the southwest and westerly flow continuing to pull in a dry and hot air mass over the state. PW was measured at 0.27 inches in Grand Junction this morning, and very low relative humidity values are forecast again. Surface winds should be slightly lower today, so while Elevated fire weather is forecast across the western border, a Red Flag Warning has only been issued for the Colorado River Headwaters (below 7,500 feet).

The strengthening ridge and general dryness east of the Continental Divide will be too much for storm development this afternoon/evening. Denver’s morning sounding measured PW at 0.45 inches and showed very dry levels above 700mb. High moisture will still exist over the eastern border counties, but a strong cap and no lifting mechanism to initiate storms means that precipitation chances are close to zero. Flooding is NOT forecast today.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.

Zone-Specific Forecasts:

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

A Red Flag Warning has been issued for the Colorado River Headwaters this afternoon. Southwest winds are forecast to be in the 15 to 25 mph range with gusts up to 45 mph possible. Elsewhere, along the border, fire danger will still be elevated due to dry fuels and low moisture. It will be too dry for any rainfall to develop over the mountains this afternoon. However, as the trough off the California coast starts to move inland today, expect upper level cloud cover to accompany it by mid-afternoon (see Utah/Arizona in above image). High temperatures will reach into the mid to low 90Fs across the valleys/slopes with mid 80Fs for the mountain valleys. Flooding is NOT forecast.

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

The ridge continues to build in strength today, so high temperatures are forecast in the low to mid-90Fs across the I-25 corridor again. Out east, where cloud cover can linger a bit longer, highs will be in the mid to upper 80Fs. If it burns off rather quickly, expect highs around 90F. Low to mid-80Fs are forecast for the mountain valleys. Between the building ridge and dry atmosphere, rainfall chances are close to zero today. No mechanisms to break the cap over the eastern plains where higher instability will exist, so flooding is NOT forecast. Expect an increase in cloud cover over the mountains and adjacent plains overnight as the trough and jet begin to approach the state from the west.