Issue Date: 6/27/2018
Issue Time: 7:25 AM

NO FLOOD THREAT IS FORECAST TODAY.

The main story today will be the hot temperatures underneath the strong high pressure ridge that has settled over the region. High temperatures will be a degree or two warmer, with a swath of 100+ degree high temperatures blanketing the Arkansas River valley in the Southeast Plains. If you must be outside today, it will be important to take plenty of water breaks and find shade when possible.

Respite from the otherwise hot day will come in the form of isolated afternoon/evening thunderstorms over portions of central and eastern Colorado. Over the higher terrain of the Northern Mountains, Central Mountains, and Southeast Mountains, a couple isolated thunderstorms are expected as strong daytime heating works alongside orographic forcing. The lack of moisture in these regions will lead to gusty winds, virga, and lightning, with very little (if any) rainfall.

A weak surface boundary will ease its way through northeastern Colorado, settling just south of the Palmer Ridge this afternoon. Upslope flow behind the front will allow for shallow moisture to work back into Colorado, providing just enough fuel for strong daytime heating to produce isolated thunderstorms. Thunderstorms will produce more wind and lightning than rain due to the dry low-levels, so no flood threat is warranted. Strong winds up to 60 mph and small hail will be the most that the strongest storms can muster.

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, jump below the map.

Zone-Specific Forecasts

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

Hot temperatures and abundant sunshine will be the main weather story today, as the mercury climbs a few degrees higher than yesterday. A weak surface boundary will ease through northeastern Colorado and settle over/near the Palmer Ridge, with upslope flow behind the front bringing an increase in shallow moisture. This will provide the fuel for a few isolated thunderstorms this afternoon and evening over the Front Range, Urban Corridor, Palmer Ridge, Northeast Plains, and northernmost portions of the Southeast Plains. Strong winds and lightning will be the main impact from thunderstorms as the low-levels remain too dry for heavy rainfall. One or two storms will become strong-to-severe, producing strong winds up to 60 mph and small hail. Maximum rain rates are as follows:

Front Range: 0.05-0.15 inches/hour
Urban Corridor, Palmer Ridge, and Southeast Plains: 0.2-0.4 inches/hour
Northeast Plains: 0.25-0.5 inches/hour

Timing: 2 PM – 8 PM for the Front Range and Urban Corridor, 3 PM – 10 PM for the Palmer Ridge and northern portions of the Southeast Plains, and 3 PM – Midnight for the Northeast Plains

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

Hot and dry, with plenty of sunshine to go around. High temperatures will nudge a degree or two higher than yesterday’s readings, with lower valleys near the CO/UT border reaching into upper 90s and low 100s. Red Flag Warnings have been issued for this afternoon and evening across much of the area, so be sure to check with your local NWS office for more information.

During the afternoon and early evening hours, a couple isolated thunderstorms will develop over the higher terrain of the Central Mountains, Southeast Mountains, and Northern Mountains regions thanks to strong daytime heating. Owing to the lack of moisture present, this activity will produce virga, gusty winds, and lightning, but very little (if any) rainfall. Rain rates will remain below 0.1 inches/hour.

Timing: 1 PM – 7 PM

Issue Date: Tuesday, June 26, 2018
Issue Time: 08:35AM MDT

— Flooding is NOT expected today

The ridge marked in the visible imagery below will slide east today over Colorado. Currently, Colorado is under northwest flow aloft, and this will become more westerly this afternoon as the ridge flattens out due to a passing trough to the north. This should pull in dry, warm air and mix out the majority of the residual surface moisture. Temperatures are expected to continue to climb today with highs reaching close to 100F over the Southeast Plains, San Luis Valley and Grand Valley. Other lower elevations will reach the mid-90Fs with low 80Fs in the mountain valleys. Low level water vapor imagery shows there is a small disturbance in the ridge that is currently over northern Utah. As this moves over Colorado later this afternoon/evening, it is forecast to increase cloud cover over the mountains. However, since not much moisture will be available for showers and thunderstorms only trace amounts of rainfall are expected with plenty of virga. There may be some brief, gusty winds under the cores of the elevated storms. As anticipated, flooding is not expected today.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. For Zone-Specific forecasts, scroll below the map.

Zone-Specific Forecasts:

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

A little bit of fog today over the northeast corner of the state as seen in the visible satellite image. This should burn off quickly as the sun provides some warming. Showers and thunderstorms are not expected today due to very dry air in the lower levels, but there will be some increased cloud cover this afternoon over the higher terrains. Plenty of virga with these elevated storms, so there may be some brief, gusty winds. High temperatures will climb to the mid-90Fs and above over the lower elevations with 70Fs and 80Fs in the mountains.

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

Over the northwest corner of the state, critical fire weather will be reached as the upper level disturbance over Utah ushers in gusty winds to drop humidity levels to the single digits. A Red Flag Warning is in place through this evening. Elsewhere, there will be some increased cloud cover over the higher terrains this afternoon, but rain is not expected. High temperatures will be on the rise increasing 5-8F from yesterday and the Grand Valley and San Luis Valley may hit 100F.

Issue Date: Monday, June 25, 2018
Issue Time: 08:30AM MDT

— Flooding is NOT expected today

The upper level low that brought widespread showers to the eastern portion of the state and cooler temperatures will begin to move to the east today. That also means the trailing showers over the eastern plains will come to an end this afternoon. Behind the low, a ridge (marked in the water vapor imagery below) will begin to slide over the state and promote northwesterly flow aloft. Dry air and general subsidence will cease shower and thunderstorm activity over the state today. Expect a few cumulus clouds over the higher terrains this afternoon, but it should remain clear elsewhere. Temperatures will also be on the rise heating up 10-15F when compared to yesterday. To the west, the eastward movement of the jet stream means a break from widespread critical fire weather. Though, some isolated ridgetop gusts up to 25 mph are expected this afternoon. Flooding is not forecast today.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. For Zone-Specific forecasts, scroll below the map.

Zone-Specific Forecasts:

Northeast Plains:

Spotty showers continue over the Northeast Plains that are associated with the upper level low. They will continue their eastward progression throughout the morning into the early afternoon. Cloud cover will keep temperatures a bit cooler today. Totals up to 0.25 inches are possible, but flooding is not expected.

Primetime: Ongoing to 4PM

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

Showers and thunderstorms are not expected today as general subsidence and drier air moves into the state. Temperatures will start to increase (10-15F) with highs much closer to normal for this time of year. A few cumulus may form over the higher terrains and Palmer Ridge this afternoon, but it should remain clear elsewhere.

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

As the upper level jet slides east, there will be a break in widespread critical fire weather. There is still a chance for some gusts over the high ridges this afternoon, but it should remain calm otherwise. Temperatures are forecast to reach 90F in the valleys and 65-70F over the higher terrains. Clear skies overnight will allow temperatures to drop into the mid 50Fs and 60Fs.

Issue Date: 6/24/2018
Issue Time: 9:32 AM

A LOW FLOOD THREAT HAS BEEN ISSUED FOR PORTIONS OF THE URBAN CORRIDOR, PALMER RIDGE, NORTHEAST PLAINS, SOUTHEAST PLAINS, AND RATON RIDGE.

An active day of showers and thunderstorms is expected as the upper-level low currently situated over Wyoming shifts eastward, reaching north-central Nebraska later tonight. As it does so, broad-scale support will be in place across Colorado, with a shortwave axis acting as the trigger for scattered-to-widespread showers and thunderstorms today and into the late evening hours. Isolated-to-scattered showers/thunderstorms will get their start over the Northern Mountains, Central Mountains, and Front Range during the late morning hours (11 AM – Noon), with those storms moving eastward with time. This early activity will be capable of gusty winds, lightning, and periods of light-to-moderate rainfall, but not much more. Showers/storms will continue over these regions through the afternoon, diminishing during the early evening hours.

The main show today will occur east of the mountains, where better moisture, instability, and favorable wind shear coincide with the passage of the upper-level low. Scattered-to-widespread showers and thunderstorms are expected to kick off around lunchtime, increasing in coverage through the afternoon and early evening hours, tracking generally eastward with time. The strongest storms of the day will occur over southern portions of the Northeast Plains, eastern portions of the Palmer Ridge, and across the Southeast Plains and Raton Ridge, where the best instability resides. Strong winds, large hail, and periods of moderate-to-heavy rainfall will attend this activity. Relatively quick storm motions will help mitigate the flood threat, so only a low flood threat is warranted. Activity will diminish from northwest to southeast, with storms ending/exiting the state completely by 11 PM.

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, jump below the map.

Zone-Specific Forecasts

Urban Corridor, Palmer Ridge, Northeast Plains, Raton Ridge, and Southeast Plains:

Scattered showers and thunderstorms are expected, beginning around lunchtime over the Urban Corridor and Palmer Ridge, developing and spreading eastward with time. The strongest storms of the day are expected over eastern portions of the Palmer Ridge, southern portions of the Northeast Plains, Raton Ridge, and the Southeast Plains. Large hail, strong winds, and an isolated tornado or two cannot be ruled out. Maximum rain rates are as follows:

Urban Corridor: 1.0-1.4 inches/hour
Northeast Plains and Palmer Ridge: 1.2-1.6 inches/hour
Southeast Plains and Raton Ridge: 1.8-2.2 inches/hour

The main threats will be street/field ponding in poorly drained areas, flooding of low-lying areas and intersections, and small stream/creek flooding. Relatively quick storm motions to the east will mitigate the flood threat somewhat, as heavy rainfall residence time will be reduced.

Timing: 11 AM – 9 PM for the Urban Corridor and Palmer Ridge, Noon – 9 PM for the Northeast Plains, 1 PM – 11 PM for the Southeast Plains, and 3 PM – 11 PM for the Raton Ridge.

Northwest Slope, Northern Mountains, Central Mountains, Front Range and Southeast Mountains:

Isolated-to-scattered showers/thunderstorms are expected to begin late this morning and continue into the evening hours. Most showers/storms will be garden variety, producing gusty winds and periods of light rainfall. A stronger thunderstorm or two over the Front Range and Southeast Mountains will be capable of producing small hail, brief moderate rainfall, and strong winds. Maximum rain rates are as follows:

Front Range and Southeast Mountains: 0.4-0.7 inches/hour
Northern Mountains, Central Mountains: 0.2-0.4 inches/hour
Northwest Slope: 0.05-0.15 inches/hour

Timing: 11 AM – 7 PM for the Northwest Slope and Northern Mountains, 11 AM – 9 PM for the Front Range and Central Mountains, and 1 PM – 10 PM for the Southeast Mountains

Grand Valley, San Juan Mountains, San Luis Valley, and Southwest Slope:

Mostly sunny, cooler, and dry will be the name of the game today. High temperatures will be about 4-8 degrees cooler than average.