FTB 06-30-2020: Fire Danger Remains Elevated Across Southern Colorado

Issue Date: Tuesday, June 30th, 2020
Issue Time: 8:55AM MDT

— Flooding is NOT expected today

Not much change in the location of the Low from yesterday. Today it will continue to lift to the northeast, which will push a vorticity max (purple “X” on the right) and rain showers associated with this southwest jet eastward. Behind the speed maximum, flow aloft will become more westerly, which should mix out a lot of the surface moisture. There will also be general subsidence; thus, outside of some high-based storms over the Northeast Plains producing light rainfall along the speed max, it should remain dry over eastern Colorado. High surface winds are forecast over portions of the Southeast Mountains, San Juan Mountains, and San Luis Valley with higher winds speed aloft today. Paired with very dry air and low relative humidity values, a Red Flag Warning has been issued.

Additional weak storms are possible over the Northwest Slope as a second disturbance (purple “X” on left) moves over the area. Again, not much moisture associated with this shortwave and overall system, which can be seen by the yellow shade over the state below. So, the main threat will be some brief, gusty outflow winds under the stronger storms with only a little accumulation forecast for the Northern Mountains. As anticipated, 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:

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

Some weak showers are possible this evening and tonight over the Northwest Slope and Northern Mountains as a shortwave moves overhead. Accumulations will be light over the Northern Mountains with totals under 0.10 inches. Temperatures this afternoon will also be cooler than yesterday by 5-10F. This cool off will be short-lived, so be sure to enjoy it.

Primetime: 4PM to 11PM

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

As the speed maximum and associated cloud cover moves eastward, some light showers will be possible over the Northeast Plains where moisture is a little higher. Storms will likely produce more wind than rain over the border counties, but max 1-hour rain rates up to 0.25 inches will be possible in that area. Subsidence and dry westerly flow aloft will keep the eastern mountains/adjacent plains quiet this afternoon, and cooler temperatures are also expected behind the front (5-10F). Flooding is not forecast.

Primetime: 2PM to 8PM

Southeast Mountains, Raton Ridge, San Juan Mountains, & San Luis Valley:

Higher fire danger is anticipated in portions of these regions with the dry air mass and jet overhead. Highest fire danger today will be over the San Luis Valley and eastern San Juan Mountains. Winds are forecast from the west between 10 and 20 mph with gusts up to 35 mph possible. Higher gusts are possible over the mountain passes such as Wolf Creek Pass. Some gusty winds could fill into the I-25 corridor, although Red Flag Warnings are not issued at this time. Be sure to tune into your local NWS office for the latest on the elevated fire danger.

FTB 06-29-2020: Critical Fire Weather & Windy Conditions

Issue Date: Monday, June 29th, 2020
Issue Time: 9:10AM MDT

— Flooding is NOT expected today

The strong Low pressure system has migrated into Idaho, and the jet that’s rotating around base of the trough will move east into Colorado throughout the day. This southwest flow will pull in a fairly dry air mass over the state, and it will help to mix out the majority of the residual surface moisture. Increased surface winds are also forecast across the state with the jet overhead and a developing lee trough, which will elevate fire danger (pink dotted line). So other than some weak, high-based showers over the northwest corner of the state, it should remain dry, hot, and windy. A cold front begins to move into the state from the west later this evening, so expect southwest winds to shift to the northeast as the front passes. There may be some weak showers over the mountains this evening/overnight associated with front, but more stratiform clouds are forecast than wetting rainfall. Like everyone else, I’m looking forward to those cooler temperatures tomorrow. Flooding is not forecast 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:

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

A couple high-based storms will be possible this afternoon over the northwest corner of the state as mid-level energy mixes with some residual moisture. Overall, the dew point depression will be large, so only light rainfall and sprinkles are forecast from the storms. The main threat will be gusty outflow winds on top of already higher winds. Additional weak showers may be possible along the front overnight, but flooding is not forecast. Tune into your local NWS office for the latest on Red Flag Warnings that have been issued.

Primetime: 2PM to 5AM

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

It’s going to be a hot one with highs forecast to reach the mid to upper 90Fs along the I-25 corridor. Highs will likely reach the triple digits over the far eastern plains. It will be windy this afternoon with a developing lee trough, so tune into your local NWS office for the latest on Red Flag Warnings that have been issued. It’ll be too dry for afternoon rainfall, but expect an increase in cloud cover this afternoon to help with the heat.

FTB 06-28-2020: Approaching Disturbance to Bring More Wind Than Rainfall

Issue Date: Sunday, June 28th, 2020
Issue Time: 8:55AM MDT

— Flooding is NOT expected today

An impressive disturbance was noted on visible satellite this morning, see below, with the upper level trough located over northern Oregon as of 8:30AM MDT. The accompanying surface low was located over the Great Basin, forcing some morning showers and even a few weak thunderstorms in northern Utah. This disturbance will not be in any particular hurry today and will slowly approach Colorado as it digs southeastward. However, cooler mid-level temperatures and some mid-level dynamics on the outskirts of the trough imply a higher coverage of showers and thunderstorms today over central and western Colorado.

While the PW at Grand Junction (0.68 inches) appears fairly elevated, an inspection of this morning’s sounding shows that the vast majority of the moisture lies well above the boundary layer. As such, any thunderstorms that do form this afternoon will be much more effective at producing gusty winds than rainfall. By this afternoon, an area of very strong mid-level winds is expected to approach western Colorado. This sets up an enhanced risk of wildfires since dry lightning will be possible, along with fairly low relative humidity. A Red Flag Warning and Wind Advisory have already been issued for the Northwest Slope, Grand Valley and Southwest Slope.

East of the Continental Divide, very warm weather will return today after a brief hiatus with temperatures up to 10F above normal. Isolated to widely scattered storms are possible later this afternoon, but rainfall will be limited and the main impact will be gusty winds.

Flooding is not 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:

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

Partly to mostly cloudy this morning, the scattered showers and thunderstorms, mainly over the higher terrain. Max 1-hour rainfall up to 0.4 inches possible. Flooding is not expected today.

Winds will pick up this afternoon, especially over the Northwest Slope with gusts above 60mph possible over the highest peaks. Furthermore, an elevated fire risk exists over the Grand Valley and Southwest Slope today due to the combination of wind speed and low relative humidity. Stay tuned to NWS forecasts and #COfire threat for updates.

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

Mostly sunny this morning then partly cloudy and hot with isolated to widely scattered showers and thunderstorms this afternoon. Coverage will be highest over the higher terrain extending northeast into the Northeast Plains. Max 1-hour rainfall up to 0.4 inches. Gusty winds, up to 45 mph, will accompany the strongest storms that do form. Flooding is not expected today.

FTB 06-27-2020: Another Round of Scattered Storms Expected for Southern Colorado

Issue Date: Saturday, June 27th, 2020
Issue Time: 8:55AM MDT

— Flooding is NOT expected today

Taking a look at the visible satellite imagery below it’s a beautiful start to the morning across the state for as much rain and severe weather as we had yesterday. As far as the synoptic set up, not much has changed. The entirety of the shortwave trough (red “L” and orange “X’s”) will push eastward through Colorado today as the next, anomalously strong Low moves inland over the Pacific Northwest. This will allow for another round of widespread, scattered storms this afternoon that should initiate over the mountains by early afternoon. Storm motion will continue to be westerly/southwesterly with flow aloft shifting to the northwest tonight as the trough moves as the trough begins to influence the state. This more westerly/southwesterly flow aloft has scoured out a lot of the low-level moisture that filled in behind the cold front yesterday and will continue to do so throughout the day, so storms are expected to be less widespread and have higher bases. This will limit their rain rate efficiency and cause storms to produce more gusty winds than wetting rainfall. With dew points less than 40F (minus the far eastern border), flooding from thunderstorms is not expected.

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:

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

Storms will favor convective initiation further south today, so that means the Southeast Mountains, Palmer Ridge, and eastern Raton Ridge. Expect less storm coverage over the Front Range/adjacent Urban Corridor. As storms move off the mountains, expect some very strong outflow winds due to the dry boundary layer. If storms are able to stay intact and make it a little further east, they should strengthen a bit in the moister environment. However, quick storm motion and relatively dry low-levels should keep the flood threat away today. Max 1-hour rain rates up to 0.15 inches (west) and 0.75 (east) will be possible. Damaging outflow winds are once again expected along with severe hail under the stronger storms. Best chance for those higher rain rates will be over southern Yuma County, Kit Carson County, northern Cheyenne County, and northern Lincoln County.

Primetime: 1PM to 10PM

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

Best chance for storms to produce rainfall today will be over the high terrains in the southwest corner and near the Continental Divide as the shortwave (slightly higher moisture content) slides across the southern border. Localized max 1-hour rain rates up to 0.20 inches (south) and 0.10 inches (north) will be possible. Dry thunderstorms this afternoon will pose a threat for fire danger as dew points drop off into the 20Fs. This will also allow storms to continue to produce very strong outflow winds. Gusts between 50 and 60 mph should be expected once again after looking at this morning’s sounding (coming from the stronger storms). Additionally, a Red Flag Warning has been issued for the San Luis Valley. Expect westerly winds in the 10 to 20 mph range with gusts up to 35 mph.

Primetime: 1PM to 8PM