— A LOW<\/strong> flood threat has been posted for parts of the Southwest Slope and Grand Valley<\/em><\/p>\n
A plume of monsoonal moisture continues to stream unusually far north, as shown in the visible satellite image below. Meanwhile, substantial drying is occurring on the eastern side of the upper-level ridge guiding the monsoonal surge. This has created a strong gradient in moisture this morning. Grand Junction PW<\/span> came in at 1.05 inches, while Denver’s is only 0.65 inches. Model initializations this morning suggest the southwest corner of Colorado is seeing PW<\/span> in the 1.0-1.2 inch range, which is much above normal. Additionally, dewpoint temperatures are 3-5F higher this morning. For example, Cortez and Durango have dewpoints of 55F or higher, which is noteworthy given their elevation of ~6,000 feet or higher. While some drying will erode moisture a bit over the eastern San Juan Mountains, we expect plenty of moisture to hang around the far southwest part of the state to support at least one if not several rounds of heavy rainfall this afternoon and evening. Yesterday’s rainfall totals were not overly impressive, but a look at individual storm cores showed intensity up to 0.4 inches in 10 minutes. Instability today will be higher, up to 1,400 J\/kg. This, coupled with veering southerly steering flow over time should limit cloud cover to the south of the region (due to lower terrain in northern New Mexico), and support a longer period of instability. Thus, a MODERATE flood threat is warranted for a climatologically preferred but narrow region on the west side of the San Juans where up to 2.0 inches of rainfall is possible through tomorrow morning. Mud flows and debris slides are possible given the steep terrain here. Further north, a LOW flood threat extends through the Uncompahgre Plateau, but drier air north of there is expected to limit rainfall efficiency.<\/p>\n
![\"\"](\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/07\/vis_markup-4.png\")
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