Issue Date: 6/4/2017
Issue Time: 9:00 AM

NO FLOOD THREAT IS FORECAST.

The upper-level low that helped produce a few showers/thunderstorms over eastern Colorado yesterday has finally drifted out of the state, centered over the TX/OK panhandle. Following it, the upper-level ridge will continue to build over the region today, resulting in a mainly dry day for Colorado. The exception to the dry rule will be over the higher terrain, where daytime heating & orographic effects will work on residual moisture, producing a few weak showers/thunderstorms. Rainfall will generally be light, with a few small pockets of moderate rainfall, but nothing to warrant any flood threat concerns.

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, Southeast Plains, and Raton Ridge:

Sunny and dry, with high temperatures reaching a few degrees above normal for the date. There isn’t much else to say except urge you to get outside and enjoy this early June day.

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

Mostly sunny and mainly dry conditions will prevail, especially in the valleys and lower elevations. A few isolated, weak showers/thunderstorms will develop during the afternoon and evening hours, thanks to daytime heating and orographic effects playing on residual moisture. Heavy rainfall is not expected, and thus no flood threat is warranted. Rain rates will generally be in the 0.05-0.15 inches/hour range, with small pockets of 0.15-0.25 inches/hour. Gusty winds and some lightning will also attend thunderstorms.

Timing: Noon – 10 PM

Issue Date: 6/03/2017
Issue Time: 9:00 AM

A LOW FLOOD THREAT IS FORECAST TODAY FOR PORTIONS OF THE NORTHEAST AND SOUTHEAST PLAINS.

The water vapor image below tells the story for today, with an upper-level high positioned/building over the southwestern US and a shortwave low-pressure trough spinning over northeast CO/southwestern NE. With this pattern in place, drier (and more stable air) will filter in from the west with time, but eastern Colorado will have to contend with scattered showers and thunderstorms as the shortwave slowly moves south-southeastward. A few isolated showers and thunderstorms are also expected over the higher terrain along/east of the Continental Divide this afternoon/early evening where lingering moisture is worked on by daytime heating. West of the Continental Divide is expected to remain dry throughout the period.

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

Scattered showers and thunderstorms are expected to develop around noon, peaking in coverage/intensity around 4-6 PM, and diminishing by around sunset. Most of the activity will remain over the Northeast Plains and Southeast Plains, but an isolated shower/thunderstorm or two is expected for portions of the Urban Corridor, Palmer Ridge, and Raton Ridge. Generally speaking, rain rates will remain below flash flood threat thresholds, but maximum rain rates over the eastern plains and eastern portions of the Raton Ridge are the reason for the low flood threat.

Front Range, Urban Corridor, and Raton Ridge: 0.25-0.5 inches/hour
Northeast Plains and Palmer Ridge: 0.8-1.2 inches/hour
Southeast Plains: 1.0-1.5 inches/hour

Timing: Noon – 10 PM

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

A few isolated-to-widely scattered showers/thunderstorms are expected over the higher terrain along the Continental Divide and east, with dry conditions expected to the west. With moisture waning, heavy rainfall is not a threat today, so no flood threat has been issued. Rain rates will generally be 0.1-0.25 inches/hour, with a brief period of heavier rain to the tune of 0.25-0.5 inches/hour possible over the Central Mountains.

Timing: Noon – 10 PM

Issue Date: Friday, June 2nd, 2017
Issue Time: 10:30AM MDT

— MODERATE flood threat for parts of Northeast Plains and Southeast Plains
— LOW flood threat for parts of Urban Corridor, Front Range, Palmer Ridge, Southeast Mountains, and Raton Ridge

— An update to the Flood Threat Bulletin is possible this afternoon, depending on how conditions evolve.

The steady increase of moisture continues today across Colorado. Precipitable water (PW) values are now in the 0.7 – 1.0 inch range east of the Continental Divide and 0.5 – 0.7 inches to the west. As the water vapor image shows, below, there are two disturbances that will favor upward motion, and contribute to heavy rainfall chances. The first disturbances is easily seen extending from Montana to Utah. This will continue to move E/SE today and generate late morning storms across the Front Range, spreading south and east through the day. The second disturbance is farther south in New Mexico. As this slowly moves east, it will continue to favor showers and storm chances across southern Colorado. A large area east of the Continental Divide will be under a Low flood threat today for isolated flash flooding. Near the Kansas border, a small area has been placed under a Moderate flood threat due to higher chances of flash flooding as well as relatively high antecedent moisture. The South Fork of the Republican River and Beaver Creek (Kit Carson County) should be watched for flooding later today. As such, an afternoon update is possible for the Flood Threat Bulletin.

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.

Issue Date: Thursday, June 1st, 2017
Issue Time: 10:15AM MDT

— LOW flood threat for parts of Front Range, Palmer Ridge, Southeast Mountains, Central Mountains, San Juan Mountains and Raton Ridge

Another mostly sunny morning has greeted most of Colorado, a foreshadowing of the warm day to come. Meanwhile, moisture has continued to increase across the state over the past 24-48 hours. This morning, precipitable water (PW) values are greater than 0.5 inch for almost everyone, with eastern Colorado seeing values closer to 0.8 inches. Low-level moisture will continue to slowly increase as the diurnal circulation, favoring weak easterly upslope flow, keeps advecting higher moisture into our state. By this afternoon, expect PW values to be at or above 0.7 east of the Continental Divide.

Looking at the water vapor image, below, reveals a cutoff low centered over northwest Mexico. Also (loosely) associated with this feature is a disturbance that is currently position near the Four Corners, moving slowly northeastward. This will provide large-scale upward motion, increasing shower and storm chances across western and central Colorado. Instability will be present today across most of the state, but highest chances of precipitation are limited to western and central areas. West of the Continental Divide, rainfall rates will be just below flood threat levels. However, in the foothills south of Denver all the way through the New Mexico border, there will be the potential for at least isolated heavy rainfall capable of causing flash flooding. A Low flood threat has been posted for this region.

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.