{"id":2592,"date":"2025-09-06T17:01:47","date_gmt":"2025-09-06T17:01:47","guid":{"rendered":"https:\/\/discussions.weather.arizona.edu\/?p=2592"},"modified":"2025-09-06T17:01:47","modified_gmt":"2025-09-06T17:01:47","slug":"monsoon-winding-down-storms-possible-in-tucson-this-evening-september-6th-2025","status":"publish","type":"post","link":"https:\/\/discussions.weather.arizona.edu\/?p=2592","title":{"rendered":"Monsoon winding down; storms possible in Tucson this evening: September 6th, 2025"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Yesterday&#8217;s Weather<\/h2>\n\n\n\n<p>Most of the acivity during the day yesterday was in the northern half of Arizona and New Mexico. Overnight it turned out to be more interesting as thunderstorms developed in Graham and Pima counties around 10pm before finally dissipating around 3am. These storms can be traced back to the thunderstorms that were in northwest Arizona yesterday morning before dissipating in the Phoenix area.\u00a0Another area of thunderstorms that developed in Nevada last night is now in northwest Arizona moving southeast and slowly dissipating. Upper-level disturbances created these storms and although the storms are dissipating now heating during the day will regenerate the activity this afternoon and evening.\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"792\" style=\"aspect-ratio: 1166 \/ 792;\" width=\"1166\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Recording-2025-09-06-083540.mp4\"><\/video><figcaption class=\"wp-element-caption\">GOES19 infrared satellite images from September 6th from 12pm to 7am this morning, College of DuPage<\/figcaption><\/figure>\n\n\n\n<p>Shown below are the 24-hour accumulated precipitation forecast from yesterday\u2019s HRRR-UA WRF 12Z (left) and equivalent observations from the MRMS system (right). The forecast got most areas of precipitation correct except for the overnight storms around Tucson. The stratiform precipitation associated with Lorena was farther south in Mexico than forecast. The precipitation coverage in New Mexico is more related to anvils blowing off storms and probably did not have the areal coverage or intensity shown in the accumulated precipitation map. \u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"333\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-083807-1024x333.png\" alt=\"\" class=\"wp-image-2595\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-083807-1024x333.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-083807-300x98.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-083807-768x250.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-083807-1536x500.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-083807.png 1731w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">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<h2 class=\"wp-block-heading\">Analysis<\/h2>\n\n\n\n<p>The surface dewpoint observations from this morning show there\u2019s not been much of a change in surface moisture since yesterday. Between Lake Havasu City\u00a0and Phoenix, a thunderstorm just dropped over a half inch of rain at the Smith Peak RAWS site this morning and the reason is the \u201cdynamic\u201d part of the thermodynamic equation is present. Adiabitc lift ahead of storms coming from the northeast aided the vertical push from the terrain to cause a thunderstorm to drop that amount over Smith Peak. \u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"526\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090126-1024x526.png\" alt=\"\" class=\"wp-image-2597\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090126-1024x526.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090126-300x154.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090126-768x394.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090126.png 1529w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Surface weather station observations for Arizona and New Mexico at 8:45am, <a href=\"https:\/\/www.weather.gov\/wrh\/hazards?&amp;zoom=8&amp;scroll_zoom=false&amp;center=32.656025851099066,-110.76888628244107&amp;boundaries=false,true,false,false,false,false,false,false,false,false,false&amp;tab=observation&amp;hazard=true&amp;hazard_type=all&amp;hazard_opacity=80&amp;obs=true&amp;obs_type=weather&amp;elements=temp,wind,gust&amp;temp_filter=-80,130&amp;gust_filter=0,150&amp;rh_filter=0,100&amp;elev_filter=-300,14000&amp;precip_filter=0.01,30&amp;obs_popup=false&amp;obs_density=60&amp;obs_provider=ALL\">NWS<\/a><\/figcaption><\/figure>\n\n\n\n<p>The observed sounding from Phoenix at 5am is similar to yesterday except that it is drier above the boundary layer and mixing during the day will decrease the rather high Convective Available Potential Energy (CAPE) values. Note that the winds are weak in the boundary layer.\u00a0Comparing the observations to the forecast initialization of the HRRR-UA WRF 12Z, there is more total precipitable water in the observed sounding (1.67\u201d versus 1.56\u201d), but otherwise a well initialized forecast.\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"581\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090803-1024x581.png\" alt=\"\" class=\"wp-image-2599\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090803-1024x581.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090803-300x170.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090803-768x436.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-090803.png 1395w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z initialization at 5am this morning (left), observed sounding from Phoenix at 5am this morning (right).<\/figcaption><\/figure>\n\n\n\n<p>The GOES-19 low-level water vapor satellite picture below illustrates the dry air shown on the soundings across the state. Also shown are the storms over northwest Arizona. \u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"654\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091229-1024x654.png\" alt=\"\" class=\"wp-image-2602\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091229-1024x654.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091229-300x192.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091229-768x491.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091229.png 1312w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">GOES19 low-level satellite image from September 6th at 7:30am, College of DuPage<\/figcaption><\/figure>\n\n\n\n<p>Scattered\u00a0low-level clouds across the state are not easy to see on the low-level water vapor image, so the\u00a0visible satellite picture from 7:30am this morning is also shown below. Note the dense low-level clouds across eastern New Mexico.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"670\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091034-1024x670.png\" alt=\"\" class=\"wp-image-2601\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091034-1024x670.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091034-300x196.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091034-768x503.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091034.png 1250w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">GOES19 visible satellite image from September 6th at 7:30am, College of DuPage<\/figcaption><\/figure>\n\n\n\n<p>At 250mb, a short-wave trough over northwest Arizona this morning will move east across the region during the\u00a0day and will be a focal point for thunderstorm activity today. The westerly winds will remain across the state through the week and will help strip out the low-level moisture.\u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"832\" height=\"861\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091921.png\" alt=\"\" class=\"wp-image-2604\" style=\"width:610px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091921.png 832w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091921-290x300.png 290w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091921-768x795.png 768w\" sizes=\"auto, (max-width: 832px) 100vw, 832px\" \/><\/figure>\n<\/div>\n\n\n<p>Winds are from the west at 10 to 15 knots across the region at 500mb. Temperatures are near \u20137\u00b0C across central and southern Arizona and New Mexico cooling to \u20139\u00b0C in northern Arizona. Since the flow is westerly, no significant change in temperatures is expected today.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"843\" height=\"856\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091812.png\" alt=\"\" class=\"wp-image-2605\" style=\"width:630px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091812.png 843w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091812-295x300.png 295w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091812-768x780.png 768w\" sizes=\"auto, (max-width: 843px) 100vw, 843px\" \/><\/figure>\n<\/div>\n\n\n<p>At 700mb, there is still plenty of moisture with dewpoint temperatures this morning still around 4\u00b0C across the region, but they should drop a few degrees due to mixing in the boundary layer today.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"842\" height=\"855\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091949.png\" alt=\"\" class=\"wp-image-2606\" style=\"width:632px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091949.png 842w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091949-295x300.png 295w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-091949-768x780.png 768w\" sizes=\"auto, (max-width: 842px) 100vw, 842px\" \/><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">Today<\/h2>\n\n\n\n<p>The forecast soundings for Phoenix (left) and Tucson (right) at 5:30pm look similar again. There is a slight inversion at 600mb, but by afternoon storms should be able to develop on the mountains. Thermal winds at both locations are near zero, so this may be a situation where there is training of storms on the mountains (one after another over a similar spot). The valleys will need outflows to get storms going because the low-level winds are from the west, meaning up-slope for Phoenix and Tucson metro areas.\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"578\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-093316-1024x578.png\" alt=\"\" class=\"wp-image-2607\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-093316-1024x578.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-093316-300x169.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-093316-768x434.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-093316.png 1411w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z forecast sounding for Phoenix (left), and Tucson (right), at 5:30pm this afternoon.<\/figcaption><\/figure>\n\n\n\n<p>Finally, as typical for this monsoon season, Tucson is too close to call with storms close by but maybe not close enough. The weak mid-level winds could inhibit storm propogation off the mountains. Phoenix appears to be out of luck as any storms the do form in the vicinity, will remain in the mountains. \u00a0<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"752\" style=\"aspect-ratio: 1132 \/ 752;\" width=\"1132\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Recording-2025-09-06-094147.mp4\"><\/video><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z simulated radar reflectivity forecast from 12pm this afternoon to midnight tonight.<\/figcaption><\/figure>\n\n\n\n<p>Total precipitation accumulation through tomorrow morning shows precipitation is mainly on and near the mountains.\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094414-1024x683.png\" alt=\"\" class=\"wp-image-2610\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094414-1024x683.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094414-300x200.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094414-768x512.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094414.png 1128w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Accumulated precipitation forecasts through to 5am tomorrow morning.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Tomorrow<\/h2>\n\n\n\n<p>Tomorrow\u2019s forcast shows the monsoon season is winding down. Nogales will probably be the last rain bucket to get monsoon precipitation.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"678\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094748-1024x678.png\" alt=\"\" class=\"wp-image-2612\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094748-1024x678.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094748-300x199.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094748-768x508.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-094748.png 1135w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z simulated radar reflectivity forecast from 7pm tomorrow evening.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Outlook<\/h2>\n\n\n\n<p>The GEFS plume forecast shows our last shot at precipitation is today. Another system is affecting the state next weekend, but it is not monsoonal. The ECMWF long-range forecast only shows about a tenth of an\u00a0inch of rain from this system. Through the end of September, the monsoon moisture will remain close to Arizona and any low pressure system in the westerlies can tap this to create thunderstorms.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"958\" height=\"742\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-095934.png\" alt=\"\" class=\"wp-image-2614\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-095934.png 958w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-095934-300x232.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2025\/09\/Screenshot-2025-09-06-095934-768x595.png 768w\" sizes=\"auto, (max-width: 958px) 100vw, 958px\" \/><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>.<\/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 Most of the acivity during the day yesterday was in the northern half of Arizona and New Mexico. Overnight it turned out to be more interesting as thunderstorms developed in Graham and Pima counties around 10pm before finally dissipating around 3am. These storms can be traced back to the thunderstorms that were in &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-2592","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\/2592","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=2592"}],"version-history":[{"count":9,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/2592\/revisions"}],"predecessor-version":[{"id":2616,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/2592\/revisions\/2616"}],"wp:attachment":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2592"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2592"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2592"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}