Issue Date: Sunday, September 6th, 2020
Issue Time: 8:20AM MDT

— Flooding is NOT expected today

Hot and dry conditions are expected to continue today, but the main difference will be an increase in widespread, critical fire weather. Below in orange is the area with elevated fire weather conditions, and in red is where critical fire weather conditions are expected. Smoke from the Cameron Peak fire can also be noted over the eastern plains below. The ridging pattern will begin to break down with the 500mb High pushed westward as a shortwave passes to our northeast. This will drop the northwest jet south over the northern portion of the state and lee troughing should increase surface wind speeds; especially over the eastern plains. With PW around 0.30 inches and hot temperatures forecast once again, relative humidity values are forecast to be in the low teens and single digits. A Red Flag Warning has been issued for most of northern Colorado. More details can be found from your local NWS office.

Some isolated, weak showers maybe possible over the southern Front Range/northern Southeast Mountains, but the more likely scenario is just an increase in afternoon cloud cover due to drying from downsloping winds. Therefore, flooding is not expected. The fire danger and warnings continue through Monday evening as the aforementioned strong, cold system dips south and tightens the pressure gradient.

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:

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

Hot temperatures are forecast again, similar to yesterday, with little to no afternoon cloud cover helping with the heat. Thick smoke from the Cameron Peak fire may help to keep highs down further north. Expect poor air quality over this area and most of eastern Colorado today. A large Red Flag Warning has been issued through Monday evening. Over the northern Front Range, west winds in the 10 to 20 mph range with gusts up to 35 mph are forecast. Over the adjacent plains, winds will shift from the north. Finally, over Larimer and Boulder Counties, winds will be from the northwest. Please to your local NWS office for the latest and more details. Outside of some cloud cover and possible sprinkles later this afternoon over the southern mountains, rain is not expected.

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

Another hot day here as well with temperatures similar to yesterday. Virtually no chance for rainfall, but some afternoon fair weather cumulus may form over the mountains. Critical fire weather conditions are expected over the northern portions of these zones. West winds are forecast in the 10 to 20 mph range with gusts up to 30 mph possible. With relative humidity values in the low teens to single digits, a Red Flag Warning has been issued for the lower Colorado River and Colorado River Headwaters. The statewide open fire ban remains in effect.

Issue Date: Saturday, September 5th, 2020
Issue Time: 8:25AM MDT

— Flooding is NOT expected today

Other than some light cloud cover over the southern border, the visible satellite imagery below shows no clouds over Colorado this morning. PW values are in the 0.41 to 0.46 inch range, and with more drying in the boundary layer anticipated due to westerly flow aloft, conditions should continue to remain dry. There may be another round of isolated, high-based showers over the southern high terrains, but totals should remain below 0.10 inches. This means that no flooding is expected 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:

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

Sunny today with temperatures on the rise. Highs will likely reach the century tick over the plains with upper 90Fs along the I-25 corridor. In the mountains, expect highs in the 80Fs (valleys) and 70Fs (higher terrains). Over the eastern plains, afternoon, southerly winds may reach about 20 mph providing areas of elevated fire danger. Also, a decrease in near surface smoke is anticipated from the Cameron Peak fire this afternoon (relative to this morning), but some smoke will likely remain. This is especially true in the more upper levels of the atmosphere.

As far as rain, isolated showers are possible over the southern high terrains again, but totals should remain under 0.10 inches. Stronger storms that develop may produce some brief, windy conditions. Increased fair weather cumulus over the mountains should provide a little relief from the heat. Flooding is not forecast.

Primetime: 1:30PM to 7:30PM

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

It should be clear and dry with an increase in high temperatures again today. The Grand Valley may reach the century mark with 90Fs for the valleys and 80Fs over the mountain valleys. The HRRR smoke is still showing some surface and upper air smoke this afternoon over the northern portion of these zones. Lighter surface winds this afternoon will keep the fire danger lower, although the low relative humidity values and some stronger surface winds along the northern border may created pockets of elevated fire danger.

Issue Date: Friday, September 4th, 2020
Issue Time: 09:40AM MDT

— Flooding is NOT expected today

Today will be very similar to yesterday, but a slight increase in the chance for a few raindrops exists over the high elevations of the southern mountains. Colorado remains pinned between a broad trough to the northeast and a high pressure ridge to the west (see image below). This high pressure ridge will again drift eastward towards Colorado today, keeping dry and warm weather in the forecast. This morning’s soundings show it is fairly dry over the western half of Colorado, with dew points in the 20Fs and 30Fs. The Grand Junction sounding shows a PW value of 0.3 inches, which is in the bottom 10% in terms of normal this time of year. The water vapor satellite image below shows mainly dry air encompassing much of the US West and Colorado (red/yellow colors). However, some weak surface moisture has worked its way across northern New Mexico and into the southern San Juan Mountains overnight. Dew points are a degree or two higher this morning compared to yesterday over this area. This slight increase in moisture will increase the chances for seeing clouds and maybe even a quick light shower or two over the high terrain of the southern San Juan, Central, and Southeast Mountains, but chances are still very low for accumulating rainfall due to the expected high cloud bases and limited moisture. A brief gust of wind up to 30 mph could accompany any shower that is able to generate some raindrops. The rest of the state should stay dry with high temperatures on the rise. No flooding is expected today.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. 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:

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

There will be plenty of sunshine and some smoke around today over the northern half of these zones. Temperatures should climb to above average again with high temperatures topping out in the mid 90Fs for the lower elevations of the Grand Valley. Surface winds should remain weak today as the high pressure ridge shifts east over the area, so fire danger remains lower. With diurnal heating, up-mountain slope flows will cause mountain-top convergence and some clouds to form over the southern mountain regions. A few of these clouds may be able to generate some raindrops, but plenty of sub-cloud evaporation should limit any rain accumulation to only the high elevations. Max rain rates over these high terrains should stay below 0.2 in/hr with most totals under 0.1 inches. No flooding is expected today.

Primetime: 3PM to 7PM

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

Mainly sunny for the eastern half of Colorado, but smoke from the Cameron Peak fire will continue to build up and lower air quality over the Urban Corridor. Surface winds will remain weak today as the jet stream stays well northeast of Colorado and Colorado gets engulfed more into the high pressure ridge. This will continue to keep the fire danger lower, but the dry conditions mean wildfires will still be able to burn easily. Additional smoke from other western US wildfires will also move into Colorado today, especially over the northern and eastern regions.

Temperatures will rise above average again today, with high temperatures into the upper 80Fs and low 90Fs forecasted. Some clouds and a few raindrops are possible over the high terrains, especially the southern Front Range and Southeast Mountains, but a cap should limit any precipitation from falling over the plains regions. Max rain rates should stay below 0.1 in/hr over the high elevations. No flooding is expected today.

Issue Date: Thursday, September 3rd, 2020
Issue Time: 09:40AM MDT

— Flooding is NOT expected today

A cold front made its way south along the plains of eastern Colorado this morning, which brought brief gusty winds up to 40 mph. This front does not have much moisture with it, as dew points behind the front are in the 30Fs, so it will not increase precipitation chances today. The true color satellite image below shows there aren’t any clouds associated with the cold front, indicating the limited moisture. In fact, the front is pushing higher surface moisture out of the area in the Southeast Plains, where dew points were in the low 50Fs earlier this morning. The front will act to keep high temperatures slightly cooler today along the plains, but not by much. Above average temperatures will continue along the western slope. Stronger upper-level flow will shift east today between the broad trough over the Great Lakes and the eastward building high pressure ridge over the West Coast (see image below). This will act to weaken pressure gradients over Colorado, so weaker surface winds are forecast, which will lower the fire danger. Northwest flow over northern Colorado is pushing some smoke from the Cameron Peak wildfire into the northern Urban Corridor and lowering air quality. Other than some smoke back in the forecast, most of Colorado will see clear and dry weather today. No flooding is expected.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. 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, Urban Corridor, Front Range, Palmer Ridge, Raton Ridge, Southeast Mountains, & Southeast Plains:

A passing cold front will cool temperatures down by a tick or two today, but limited moisture behind this front and stable conditions will keep precipitation chances near zero. Expect clear skies once again today, so no flooding is expected. Some smoke may lower air quality for the northern Urban Corridor, but current Colorado wildfires are not producing large amounts of smoke due to increased containment.

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

Mostly sunny and warm today, with high temperatures getting into the low 90Fs for the Grand Valley and Southwest Slope. A few mountaintop, fair weather clouds could pop up with diurnal heating, but no measurable precipitation is expected today. Winds along the Northern Mountains should be weaker today, so fire danger is lower. However, spark-producing activities should still be avoided due to low relative humidity and dry fuels.