FTB 05-23-2020: Critical Fire Weather Expands & Isolated Storms are Forecast for the Northeast Plains

Issue Date: Saturday, May 23rd, 2020
Issue Time: 9:05AM MDT

Flooding is NOT expected today

The base of the trough is just to our west this morning and will slowly migrate eastward. This will increase southwest flow and place the jet stream directly over the state. Higher wind speeds are forecast to mix down to the surface by noon causing winds to increase into the 15 to 25 mph range with gusts between 35 to 45 mph. Very dry air is still indicated over New Mexico and Arizona by the lack of cloud cover in the visible satellite image below, so this will cause Red Flag Warning conditions for the majority of the state (mostly lower elevations) as relative humidity values are expected to drop into the teens and single digits.

Over the far northwest corner of the state, southeast surface winds will keep higher moisture in place as a surface low develops near the Palmer Ridge. This will be the best shot for measurable precipitation this afternoon; first along the dry line and then along the cold front later this evening. Brief, strong winds and large hail will be the main threats for the severe thunderstorms that form along the dry line. Over the mountains, except some scattered storm development over the Central and Northern Mountains as a second surge of cold air moves in associated with the upper level Low. More virga and gusty winds are expected than measurable rainfall for this region. Rainfall will not meet flood threat criteria today, so 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:

Northwest Slope, Northern Mountains, Front Range, Central Mountains, Urban Corridor, Palmer Ridge, Northeast Plains:

Cooler temperatures are forecast for the Northwest Slope today due to the cold front that moved through yesterday evening. With a second surge of cold air forecast tonight, there is a Freeze Watch in place for the Yampa River Basin. Today, scattered storm activity is forecast for the Central/Northern Mountains and Front Range with the best chance of accumulation along and west of the Divide. Max 1-hour rain rates up to 0.20 inches will be possible with lots of virga and gusty outflow winds.

Back east, max 1-hour rain rates along the dry line could reach 1.25 inches with dew points in the 50Fs. Large hail and strong outflow winds will be the main threats, but coverage will be too small in area to create any flood threat. Along and just behind the cold front that moves through overnight, max 1-hour rain rates up to 0.75 inches will be possible.

Primetime: 2PM to 1AM

Grand Valley, Southwest Slope, San Juan Mountains, Southeast Mountains, Raton Ridge, San Luis Valley, & Southeast Plains:

A Red Flag Warning has been issued from noon today until sundown tonight for the lower elevations, so be sure to tune into your local NWS office for the latest. Southwest winds will pick up into the 15 to 25 mph range with gusts up to 40 mph possible. Be sure to use caution with any open flames and avoid burning. Rainfall chances increase tomorrow east of the Continental Divide behind the cold front with wet snow forecast for the high elevations as the snow line drops overnight. Cooler temperatures and light surface winds should also decrease the critical fire conditions west of the Divide.