FTB 09-28-2017: Another Round of Showers for Eastern Colorado as the West Begins to Dry Out

Issue Date: Thursday, September 28, 2017
Issue Time: 10:40 AM MDT

— Flooding is NOT expected today

Showers continue this morning over the eastern high terrains and adjacent plains. The showers over the Southeast Plains are being support by the jet stream, which has lifted north with the Low pressure system. Dense fog was reported over Delta County with visibility down to 50 feet. Other automated stations over the mountains have also reported fog with the decreased temperatures and high dew points. Precipitable Water (PW) at Denver this morning was 0.77 inches and 0.64 inches in Grand Junction. The western portion of the state is better positioned in the dry slot today, so PW is expected to decrease throughout the day. The entrainment of dry air with the more southwest flow will limit rainfall totals over the higher terrains and valleys and decrease shower activity throughout the day.

Another day of unsettled weather and little sunshine as the upper level Low continues to slowly lift to the northeast. The jet stream and mid-level energy will provide ample vertical motion for showers and isolated thunderstorms over the mountains and eastern plains today. Moisture will remain above climatology with the southerly and southwesterly surface winds east of the Continental Divide. Expecting the first round of showers, currently over the Southeast Plains, to move northeast throughout the morning before the next round of showers this afternoon and evening. With cloudy skies, not much instability should build this afternoon, so the threat for thunderstorms and high hourly rain rates are marginal. Highest 24-hour accumulations are expected over the southern portion of the Southeast Plains with totals up to 1.5 inches. Over the higher terrains, the highest accumulations are expected over the Southeast Mountains and western Raton Ridge again. Expected more isolated showers over the northern high terrains this afternoon and evening. Snow will be likely again at the higher elevations with the snow line dropping to around 9,000 feet overnight. Overnight, showers will remain in place over the eastern plains and Southeast Mountains, but expecting little to no accumulation north of I-70. 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:

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

With most of the region being under the influence of the dry slot, showers are expected to decrease in coverage and intensity throughout the day. More isolated showers are expected over the higher terrains this afternoon with max 3-hour rain rates up to 0.7 inches (north), 0.4 inches (central) and 0.8 inches (southeast) possible. Flooding is not expected today.

Primetime: 11AM to 10PM

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

Cloudy with showers this morning over the southern mountains and eastern plains. Another round of showers is expected later this afternoon and evening after the first round exits the region to the northeast. Over the higher terrains, max 3-hour rain rates up to 0.6 inches (south) and 0.4 inches (north) are possible. Over the Southeast Plains, max 3-hour rain rates up to 1 inch are possible. Flooding is not expected today.

Primetime: 11AM to 7AM