{"id":1010,"date":"2025-07-18T17:28:17","date_gmt":"2025-07-18T17:28:17","guid":{"rendered":"https:\/\/discussions.weather.arizona.edu\/?p=1010"},"modified":"2025-07-19T16:48:35","modified_gmt":"2025-07-19T16:48:35","slug":"isolated-mountain-storms-today-and-maybe-nighttime-rumbler-july-18th-2025","status":"publish","type":"post","link":"https:\/\/discussions.weather.arizona.edu\/?p=1010","title":{"rendered":"Isolated mountain storms today, and maybe nighttime rumbler?: July 18th, 2025"},"content":{"rendered":"\n

Yesterday’s Weather<\/h2>\n\n\n\n

The Mesoscale Convective Vortex<\/a> (MCV) in western Arizona moved northwest into California west of Las Vegas and storms were limited to far northwest Arizona. Storms were limited in the rest of Arizona due to warm air aloft advecting in from the south. Storms in the mountains that did form had their tops ripped off by strong winds aloft. <\/p>\n\n\n\n

GOES19 long-wave infrared from July 17th 10am to 3am this morning, College of DuPage<\/figcaption><\/figure>\n\n\n\n

New Mexico continued to have storms over the eastern portion of the state while the rest of the state saw mostly mountain storms. <\/p>\n\n\n\n

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HRRR-UA WRF 12Z 24-hour precipitation accumulation forecast from yesterday (left) versus observed 24-hour precipitation accumulation from MRMS multi-sensor data (right)<\/figcaption><\/figure>\n\n\n\n

Analysis<\/h2>\n\n\n\n

A tropical upper tropospheric trough (TUTT) is near San Diego now and continues to move north while the other TUTT has moved west to near Durango, Mexico with a north-south convergence center between the two circulations. Ther e is a col along the mainland Mexico side of the Gulf of California, from Guaymas to Culiacan and should be a location for strong convection today. <\/p>\n\n\n\n

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GOES19 upper level water vapor images from July 18th 9:30am, College of DuPage<\/figcaption><\/figure>\n\n\n\n

Stong southerly winds are over Arizona at 250mb, with maximum winds of 50 knots. This will push anvils well to the north ahead of the storms. The ridge is centered over northern Mississippi with ridge axis extending from North\/South Carolina border west to northern New Mexico.<\/p>\n\n\n

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At 500mb, the TUTT to our west has a center in about the same position as at 200mb, south of San Diego, and is moving north. The 500mb low associated with the other TUTT to our southeast, is further southeast of the 200mb center, implying baroclinicity. The warmest air aloft is over southeast Arizona, but models show that by late afternoon cooling will occur as the circulation from the TUTT to our southeast brings in some cooling into this area. The flow in western Arizona is stronger from the south. New Mexico has mostly light winds withe the coldest air aloft remaining in eastern New Mexico. <\/p>\n\n\n\n