{"id":16301,"date":"2021-09-27T10:20:05","date_gmt":"2021-09-27T16:20:05","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=16301"},"modified":"2021-09-28T07:58:31","modified_gmt":"2021-09-28T13:58:31","slug":"ftb-09-27-2021-isolated-heavy-rainfall-threat-returns-to-southwest-colorado","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=16301","title":{"rendered":"FTB 09-27-2021: Isolated Heavy Rainfall Threat Returns To Southwest Colorado"},"content":{"rendered":"

Issue Date: Monday, September 27th, 2021
\nIssue Time: 10:18AM MDT<\/p>\n

— A LOW<\/strong> flood threat has been posted for parts of the San Juan Mountains<\/em><\/p>\n

Although cut-off lows usually require meteorologists to carry extra ibuprofen, we still secretly like them. This morning’s visible satellite image, below, shows a distinct cut-off circulation over western New Mexico responsible for ongoing showers and weak thunderstorms over a large swath of the Four Corners region. The low has moved slowly eastward since yesterday morning, has deepened a bit and will continue to do so as it begins to feel the synoptic scale lift from a strong incoming trough<\/span> further to the northwest. Notably colder temperatures aloft have now moved into New Mexico and will enter southwest Colorado today. Yesterday’s QPE<\/span> up to 0.50-0.75 inches over the San Juan Mountains carried max hourly rain rates of up to a rather impressive 0.5 inches with very limited instability and moisture. In addition, isolated<\/span> heavy rainfall, near 1.5 inch\/hour, was observed over central AZ higher terrain yesterday. Thus, we expect that today’s rainfall intensity will very likely be higher over southwest Colorado. This morning’s Precipitable Water<\/span> (PW<\/span>) was 0.61 inches at Grand Junction and 0.48 at Denver. A PW<\/span> of 0.78 inches was measured at both Albuquerque and Flagstaff, and boundary layer<\/span> moisture advection<\/span> will be from the southwest today. Thus, we expect PW<\/span> up to 0.7-0.85 in the far southwestern portion of the state. With the aforementioned cooling aloft, instability up to 1,000 J\/kg will be possible this afternoon especially over areas that see some breaks in cloud cover as is expected. Steering winds will be modest, in the 20-25mph range and will be pushing storms towards the west.<\/p>\n

Translating everything into sensible weather, with the strengthening cut-off low<\/span>, we expect several rounds of showers and thunderstorms over southwest Colorado today. During the afternoon and early evening, there will be a chance for heavy rainfall over the San Juan Mountains roughly south of a South Fork-Silverton line. A LOW flood threat has been posted for this region.<\/p>\n

Elsewhere, expect one more day of significantly above normal temperatures before cooling overtakes the state starting tomorrow and especially Wednesday.<\/p>\n

\"\"<\/a><\/p>\n

Today’s Flood Threat Map<\/strong><\/h3>\n

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.
\"\"<\/p>\n

Zone-Specific Forecasts:<\/strong><\/h3>\n

San Juan Mountains, Southwest Slope, Southeast Mountains and San Luis Valley:<\/strong><\/h4>\n

Mostly cloudy with numerous<\/span> showers and thunderstorms developing later this morning and persisting into the late evening hours. Max 1-hour rainfall up to 1.1 inches, with max 3-hour rainfall up to 1.5 inches, warranting a LOW flood threat for parts of the region. Isolated<\/span> flash flooding<\/span>, mud flows and debris slides will be possible especially over steeper terrain. Gusty winds and hail up to 1 inch could also accompany the very strongest storms.<\/p>\n

Primetime: 2PM through 11PM<\/p>\n

Front Range, Urban Corridor, Northeast Plains, Southeast Plains, Palmer Ridge and Raton Ridge: <\/strong><\/h4>\n

A few clouds this afternoon, along with continued very warm temperatures up to 12F above normal. An isolated<\/span> shower cannot be ruled out over southern areas later this evening and into the overnight hours. However, flooding is NOT expected today.<\/p>\n

Northwest Slope, Grand Valley, Central Mountains and Northern Mountains:<\/strong><\/h4>\n

Partly cloudy with temperature slightly above seasonal normal. An isolated<\/span> shower or weak storm cannot be ruled out this afternoon and evening over far southern areas, but flooding is NOT expected today.<\/p>","protected":false},"excerpt":{"rendered":"

Issue Date: Monday, September 27th, 2021 Issue Time: 10:18AM MDT — A LOW flood threat has been posted for parts of the San Juan Mountains Although cut-off lows usually require meteorologists to carry extra ibuprofen, we still secretly like them. This morning’s visible satellite image, below, shows a distinct cut-off circulation over western New Mexico […]<\/p>","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/16301"}],"collection":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=16301"}],"version-history":[{"count":3,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/16301\/revisions"}],"predecessor-version":[{"id":16314,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/16301\/revisions\/16314"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16301"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16301"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16301"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}