{"id":929,"date":"2025-07-15T17:55:14","date_gmt":"2025-07-15T17:55:14","guid":{"rendered":"https:\/\/discussions.weather.arizona.edu\/?p=929"},"modified":"2025-07-15T17:58:10","modified_gmt":"2025-07-15T17:58:10","slug":"potential-for-heavy-rainfall-in-tucson-and-even-a-few-drops-for-phoenix-july-15th-2025","status":"publish","type":"post","link":"https:\/\/discussions.weather.arizona.edu\/?p=929","title":{"rendered":"Potential for heavy rainfall in Tucson, and even a few drops for Phoenix: July 15th, 2025"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Yesterday&#8217;s Weather<\/h2>\n\n\n\n<p>Model forecasts did a reasonable job yesterday, with storms from the Mogollon Rim to the White Mountains and even showed less activity in Graham and Cochise Counties.<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"814\" style=\"aspect-ratio: 1316 \/ 814;\" width=\"1316\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Recording-2025-07-15-094809.mp4\"><\/video><figcaption class=\"wp-element-caption\">GOES19 visible satellite image from July 14th 1pm to 9:30pm, College of DuPage<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"332\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-093551-1024x332.png\" alt=\"\" class=\"wp-image-931\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-093551-1024x332.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-093551-300x97.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-093551-768x249.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-093551-1536x498.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-093551.png 1732w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 15Z 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<p>The storms in Pima and Santa Cruz Counties did not have much vertical depth thanks to the strong mid-level easterly winds and convergence aloft. Overnight low-level moisture pushed back into the state.<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"696\" style=\"aspect-ratio: 1386 \/ 696;\" width=\"1386\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Recording-2025-07-15-093258.mp4\"><\/video><figcaption class=\"wp-element-caption\">Cloud camera footage looking north from UofA campus at the Santa Catalina mountains at 3pm to 4:30pm, July 14th.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Analysis<\/h2>\n\n\n\n<p>Joining the situation today is another tropical upper tropospheric trough (TUTT) which is off the spur of the Baja. The TUTT in the Gulf of Mexico is in about the same location in the northwest of the Gulf. The TUTT in the Atlantic has weakened and moved northward with a shear zone extending southward into the central Caribbean Sea then to the TUTT in the Gulf of Mexico, and then to the new TUTT off the Baja coast (shown by the TUTT axis below).<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"606\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-095614-1024x606.png\" alt=\"\" class=\"wp-image-938\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-095614-1024x606.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-095614-300x177.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-095614-768x454.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-095614.png 1366w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">GOES19 upper level water vapor images from July 15th 9:40am, College of DuPage<\/figcaption><\/figure>\n\n\n\n<p>At 250mb, anticyclones are in Georgia and in Mexico southwest of the Big Bend, and well off the west coast of the United States. A shear axis extends northward from the low across southern Arizona and is moving slowly west along with the low. This will put southeast Arizona in divergent flow this afternoon (shown by green contours below).&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-video aligncenter\"><video height=\"746\" style=\"aspect-ratio: 742 \/ 746;\" width=\"742\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Recording-2025-07-15-100638.mp4\"><\/video><\/figure>\n\n\n\n<p>The upper low at 500mb is off the west coast of Baja and flow around the low is from the northeast at 25 knots. A ridge axis is from southern California to northern Arizona then east to Oklahoma. The winds should weaken during the day as the low moves further west.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"745\" height=\"752\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-100956.png\" alt=\"\" class=\"wp-image-940\" style=\"width:625px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-100956.png 745w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-100956-297x300.png 297w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-100956-150x150.png 150w\" sizes=\"auto, (max-width: 745px) 100vw, 745px\" \/><\/figure>\n<\/div>\n\n\n<p>At 700mb, winds are generally light from the west across the region with an axis of higher relative humidity values running from the Sierra Madre mountains in Mexico northward to southeastern Arizona. The ridge is over Big Bend and there&#8217;s low pressure southwest of the spur of Baja.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"742\" height=\"753\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-101123.png\" alt=\"\" class=\"wp-image-941\" style=\"width:618px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-101123.png 742w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-101123-296x300.png 296w\" sizes=\"auto, (max-width: 742px) 100vw, 742px\" \/><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">Today<\/h2>\n\n\n\n<p>The model forecast soundings below are for 5am and 2:30 pm at Tuscon. The mid-level winds weakening, combined with divergence aloft, and typical daytime heating means thunderstorms will fire on the mountains and move westward.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"573\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-102534-1024x573.png\" alt=\"\" class=\"wp-image-943\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-102534-1024x573.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-102534-300x168.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-102534-768x430.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-102534.png 1238w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>The HRRR-UA WRF runs for 12Z yesterday (left) and today (right) valid for this afternoon are consistent with the storms in southeast Arizona as well as the White Mountains and Mogollon rim.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"335\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103349-1024x335.png\" alt=\"\" class=\"wp-image-945\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103349-1024x335.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103349-300x98.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103349-768x251.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103349-1536x502.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103349.png 1735w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z from yesterday (left), 12Z from today (right), simulated radar reflectivity forecast for 6pm.<\/figcaption><\/figure>\n\n\n\n<p>Oddly enough Tucson airport has 1.2 inches of rain in the HRRR-UA WRF 12Z run and 0.3 inches in the latest HRRR-UA WRF 15Z. The best thing to say is that somewhere in the city both totals will happen.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"335\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103510-1024x335.png\" alt=\"\" class=\"wp-image-946\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103510-1024x335.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103510-300x98.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103510-768x251.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103510-1536x503.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-103510.png 1733w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>The 250mb divergence forecast this afternoon is also favorable for deep convection as flow is over-the-top of the ridge axis.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"688\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104016-1024x688.png\" alt=\"\" class=\"wp-image-948\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104016-1024x688.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104016-300x202.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104016-768x516.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104016.png 1112w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Overnight tonight some of the storms push up into Phoenix with the GFS (right side below) more generous than the HRRR (left side below). <\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"568\" style=\"aspect-ratio: 1740 \/ 568;\" width=\"1740\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Recording-2025-07-15-103911.mp4\"><\/video><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z (left), GFS-UA WRF 06Z (right), simulated radar reflectivity forecast from 2:30pm to 7am toomorrow.<\/figcaption><\/figure>\n\n\n\n<p>Those concerned about a dust storm\/haboob; today should be the best day for it.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"336\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104402-1024x336.png\" alt=\"\" class=\"wp-image-949\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104402-1024x336.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104402-300x98.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104402-768x252.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104402-1536x503.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104402.png 1727w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z (left), GFS-UA WRF 06Z (right), 10-meter wind speed forecast for 8pm tonight.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Tomorrow<\/h2>\n\n\n\n<p>It looks threatening, but the valleys should be pretty worked over by today&#8217;s storms. Except for storms on the mountains of the Mogollon Rim, and southwest of Tucson, they should be quickly shut down due to the lack of CAPE in the valleys. Maybe there will be enough rain to help put out the fires in the Grand Canyon.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"335\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104612-1024x335.png\" alt=\"\" class=\"wp-image-950\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104612-1024x335.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104612-300x98.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104612-768x251.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104612-1536x503.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104612.png 1735w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z  simulated radar reflectivity (left), convective available potential energy (right), forecast for tomorrow at 3pm.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Outlook<\/h2>\n\n\n\n<p>Mid-level flow will be from the southeast, and this is not favorable for organized convection until Friday. Only isolated mountain storms are expected on Thursday. GEFS plumes are equally split between no significant precipitation for the next week,&nbsp;versus a low-grade monsoon bringing less than an inch.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"973\" height=\"737\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104837.png\" alt=\"\" class=\"wp-image-951\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104837.png 973w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104837-300x227.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-15-104837-768x582.png 768w\" sizes=\"auto, (max-width: 973px) 100vw, 973px\" \/><figcaption class=\"wp-element-caption\">Global Ensemble Forecast System (GEFS) <a href=\"https:\/\/www.emc.ncep.noaa.gov\/users\/meg\/gefs_plumes\/index.html?stationname=KTUS\">plumes <\/a>for Tucson.<\/figcaption><\/figure>\n\n\n\n<p>Discussion written by Pat Holbrook and Patrick Bunn<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Yesterday&#8217;s Weather Model forecasts did a reasonable job yesterday, with storms from the Mogollon Rim to the White Mountains and even showed less activity in Graham and Cochise Counties. The storms in Pima and Santa Cruz Counties did not have much vertical depth thanks to the strong mid-level easterly winds and convergence aloft. Overnight low-level &hellip;<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-929","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/929","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=929"}],"version-history":[{"count":8,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/929\/revisions"}],"predecessor-version":[{"id":955,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/929\/revisions\/955"}],"wp:attachment":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=929"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=929"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=929"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}