FTB 07-10-2019: Weak Thunderstorms Over the Southeast Quadrant of the State

Issue Date: Wednesday, July 10, 2019
Issue Time: 9:55AM MDT

Flooding is NOT expected today

The ridging pattern aloft has continued to strengthen and is centered over Colorado this morning. Upper level flow is not expected to change much today, but low level and surface features will provide chances for afternoon and evening thunderstorms. The majority of state, west of the Continental Divide, will remain dry today as westerly and southwesterly flow aloft continues. The surface high pressure that was centered over the area yesterday has shifted to the north, allowing for moderate moisture advection and upslope flow to occur by midmorning over the southeastern portion of the state. A cold front (blue line below) moved over the eastern plains last night and into this morning, which has provided cloud cover over the Southeast Plains. Although clouds are likely to burn off by noon, cloud cover this morning will prevent moisture from mixing out rapidly, with dewpoints expected to stay in the 50°Fs throughout the region. Moisture to the north of the cloud cover will mix out and combine with downslope flow in the northern half of the state, which will limit chances for rainfall. Moisture over the eastern plains is moderate, with PW measurements increasing to the east of the foothills from 0.5 to 1.2 inches over the CO/KS border.

The high pressure system centered over the CO/WY border is expected to move eastward throughout the day, advecting warm, moist air into the southeast quadrant of the state. Mid-level flows behind the surface high are forecast to generate a vorticity maximum over the Southeast and Central Mountains (marked with an “X” below), which will combine with upslope flow to produce afternoon thunderstorms over the Raton Ridge, Central and Southeast Mountains. Storms are forecast to move off of the mountains and over the Southeast Plains later tonight and into tomorrow morning.

Riverine: As of 9:30 this morning there are no NWS Flood Warnings or Flood Advisories.  AHPS gages remain at Action stage on the Arkansas at La Junta and the Rio Grande near Alamosa due to dam releases.  To track new Flood Advisories from dam releases, tune into your local NWS office.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. For Zone-Specific forecasts, scroll below the map.

 Zone-Specific Forecasts:

Central Mountains, Southeast Mountains, Raton Ridge, Front Range, Urban Corridor, Southeast Mountains, and portions of the Palmer Ridge and Northeast Plains

Upslope flow and a passing vorticity maximum will provide lift for thunderstorms over the Central and Southeast Mountains, Raton Ridge, and southern portion of the Front Range.  Rainfall accumulations are expected to remain low as moisture and deep upper level support is lacking.  Max 1-hr rainfall rates up to 0.3 inches is forecast over the high terrain this afternoon and into the evening.  Rain is possible over the Junkins, Spring Creek and Hayden Pass burn areas but flood inducing rainfall rates are not forecast. Thunderstorms are expected to move off of the Southeast Mountains around 10PM tonight.  Storm outflow boundaries could generate storms over the Palmer Ridge and southern portion of the Northeast Plains early tomorrow morning. Max 1-hr rainfall rates of 0.6 inches are possible over the far Southeast Plains.  Dry air over the Urban Corridor will limit accumulation over the area if storms move off of the Front Range.  Only trace amounts are expected over the area.  Flooding is not forecast for today.

Primetime: 3PM to 8AM

San Luis Valley, Northern Mountains, Northwest Slope, Grand Valley, Southwest Slope, San Juan Mountains

Advection of dry air from the west and southwest will provide mostly sunny skies and warm temperatures over the area today.  Afternoon cloud cover and brief showers are possible over the San Juan Mountains due to the incoming vorticity maximum, but max 3-hour accumulations are expected to be less than 0.15 inches.  High temperatures will reach into the mid 90°Fs over the low laying areas, and will decrease into the 70°Fs and 80°Fs over the high country.

Primetime: 4PM to 9PM