\n—Threat will continue into the overnight hours<\/em>
\n—Afternoon forecast update is possible today<\/span><\/p>\n
Despite general drying, especially across central and western Colorado, above normal low-level moisture continues to hang on in the northeast quadrant of our state. As shown in the water vapor image, below, a large-scale trough<\/span> is positioned over the west coast. It is currently too far west to have a direct influence on our weather. However, it is supporting a surface low pressure system over southeast Colorado. This will maintain its intensity through this afternoon, promoting the influx of moist air into northeast Colorado. Although morning Precipitable Water<\/span> (PW<\/span>) values at the two main sounding sites, Grand Junction and Denver, are a relatively unimpressive 0.69 and 0.67 inches, respectively, much higher moisture exists just to the east. For example, the North Platte sounding’s PW<\/span> was 1.28 inches, which is in the 90+ percentile for this time of year. This moist air will be readily available for import into Colorado this afternoon and evening.<\/p>\n For today, we expect several rounds of showers and thunderstorms across mainly the northern half of Colorado as well as the far southern areas over the Raton Ridge. The highest rain coverage and intensity will be in the Northeast Plains. Afternoon and evening thunderstorms will have the potential to cause isolated<\/span> flash flooding<\/span>. In addition, large-scale outflow boundaries<\/span> are expected to arrive into northeast Colorado from convection<\/span> farther north in the late evening hours. Thus, a secondary round of isolated<\/span> heavy rainfall will be possible south and east of the South Platte River into the early overnight hours. A Low flood threat has been posted for today\/tonight for isolated<\/span> flash flooding<\/span>, street flooding and small stream flooding. Heavy rainfall coverage is not expected to be wide enough for major rivering flooding. Large hail, up to 1.75 inches, will be possible with the strongest cells this afternoon in the Northeast Plains.<\/p>\n
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