{"id":4685,"date":"2026-08-18T17:24:42","date_gmt":"2026-08-18T17:24:42","guid":{"rendered":"https:\/\/discussions.weather.arizona.edu\/?p=4685"},"modified":"2026-08-18T17:27:22","modified_gmt":"2026-08-18T17:27:22","slug":"august-18th-2026-a-gulf-surge-will-bring-moisture-back-to-arizona-for-the-next-few-days-isolated-storms-are-expected-today-but-a-significant-increase-in-strong-storms-in-both-tucson-and-phoenix-is","status":"publish","type":"post","link":"https:\/\/discussions.weather.arizona.edu\/?p=4685","title":{"rendered":"August 18th, 2026: A Gulf Surge will bring moisture back to Arizona for the next few days. Isolated storms are expected today, but a significant increase in strong storms in both Tucson and Phoenix is forecast tomorrow.\u00a0"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Summary<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Upper-level water vapor satellite imagery shows the jet stream stretching from the Pacific to northern California, with a quasi-stationary low-pressure system off the West Coast. An upper-level low just south of El Paso is splitting the subtropical high in two. It will push an inverted trough east that will change the wind direction aloft and sweep up MCS circulations happening in northern Mexico. Surface dewpoints remain similar to yesterday morning, but a Gulf Surge of moisture is moving into southwest Arizona and northwest Mexico. Elevated moisture and favorable mid-to-upper-level flow will bring more activity to the region from tomorrow on. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Today&#8217;s soundings show inversions at the top of the boundary layer and subsidence above that, meaning isolated mountain storms today, with limited rainfall expected in the valleys. Sufficient precipitable water exists, particularly near Hermosillo, which may reinforce the Gulf Surge, with another MCS possible in northern Mexico this afternoon\/evening. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tomorrow afternoon, the increased moisture raises the likelihood of thunderstorms, strong winds, dust, and heavy rain, especially for Tucson and Pima County, and outflows will take storms to Phoenix by the evening. The monsoon pattern is expected to stay active into next week, with moisture recycling and rebuilding of the subtropical helping storm development.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Yesterday&#8217;s Weather<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Thunderstorms developed, as forecast, yesterday east of the outflow boundary observed on satellite imagery on Sunday night and Monday morning. The outflow boundary brought enough mid-level moisture from storms to develop amid yesterday afternoon&#8217;s high temperatures. The thunderstorms ended soon after dark as they moved south into Mexico.<\/p>\n\n\n\n<figure class=\"wp-block-video aligncenter\"><video height=\"766\" style=\"aspect-ratio: 1240 \/ 766;\" width=\"1240\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/20260818-1518-58.4220138.mp4\" playsinline><\/video><figcaption class=\"wp-element-caption\">GOES-19 visible satellite imagery with mosaic radar and lightning overlaid from August 17th from 12 pm to 9 pm, College of DuPage.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">A thunderstorm complex developed along the Gulf of California. Outflow from the thunderstorms has produced a Gulf Surge that reached Puerto Pe\u00f1asco this morning and may move into far southwest Arizona later today. \u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"751\" height=\"347\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-141.png\" alt=\"\" class=\"wp-image-4687\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-141.png 751w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-141-300x139.png 300w\" sizes=\"auto, (max-width: 751px) 100vw, 751px\" \/><figcaption class=\"wp-element-caption\">GOES-19 infrared satellite imagery August 17th at 10 pm, College of DuPage.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The Pima County Flood Control District rain gauge data for Monday is shown below. The minimum amount of rain in the gauge must be 0.04 inches or more; anything less is not reported on this map. There were lighter amounts of rain in the eastern half of the Tucson metro area. The core of the rain shafts were small, and the heavier rain shown below only represented a small\u00a0area near the gauge (e.g., the rain gauge at Kolb and Golf Links had 0.35\u201d,\u00a0but only 0.02\u201d fell at Pat\u2019s house a few blocks north of that location). The small rain shafts were probably the reason the wind gusts were not too strong or widespread. A 41-mph wind gust was observed at Davis-Monthan AFB and Safford,\u00a0Graham County.\u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"623\" height=\"632\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-142.png\" alt=\"\" class=\"wp-image-4688\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-142.png 623w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-142-296x300.png 296w\" sizes=\"auto, (max-width: 623px) 100vw, 623px\" \/><figcaption class=\"wp-element-caption\">24-hour precipitation totals from Pima County Regional Flood Control District gauges, <a href=\"https:\/\/alertmap.rfcd.pima.gov\/gmap\/gmap.html\">Alert Map<\/a>.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The HRRR-UA WRF 12Z 24-hour accumulated precipitation forecast (left) and corresponding observed precipitation from MRMS (right) are shown below. The heaviest rain was over the mountains: Cochise County precipitation was highest near the Chiricahua Monument and the Huachuca Mountains south of Sierra Vista, receiving 1.75&#8243;.\u00a0The forecast and observed precipitation are pretty good, and the curvature south of El Paso is probably due to Tropical Upper Tropospheric Trough (TUTT) circulation centered south of the TX\/MX border. \u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"335\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-143-1024x335.png\" alt=\"\" class=\"wp-image-4689\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-143-1024x335.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-143-300x98.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-143-768x251.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-143-1536x503.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-143.png 1732w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z 24-hour accumulated precipitation forecast (left) and corresponding observed precipitation from MRMS (right) for August 17th.<\/figcaption><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">Analysis<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The upper-level water vapor satellite image shows the jet stream stretching from the Pacific Ocean to northern California (black arrow) and is associated with a large trough off the western coast of the United States (light blue &#8220;L&#8221;). A TUTT low is south of El Paso, and another is approaching the Mexican coast south of Brownsville (red &#8220;L&#8221;s). Finally, high pressure is in the southern Gulf of California, created by last night&#8217;s thunderstorm complex (dark blue &#8220;H&#8221;).<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"539\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-083929-1024x539.png\" alt=\"\" class=\"wp-image-4690\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-083929-1024x539.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-083929-300x158.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-083929-768x405.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-083929.png 1160w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">GOES-19 upper-level water vapor image August 18th at 8 am, College of DuPage.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Morning surface dewpoint temperatures haven&#8217;t changed much today compared to yesterday, but we will need to keep an eye on southwest Arizona and northwest Mexico as surge moisture moves into that area. A Mesoscale Convective System (MCS) may develop in northwest Mexico this afternoon and evening, with outflow from yesterday\u2019s MCS that will reinforce the Gulf Surge.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"553\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-084556-1024x553.png\" alt=\"\" class=\"wp-image-4692\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-084556-1024x553.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-084556-300x162.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-084556-768x415.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-084556.png 1466w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Surface weather station observations for Arizona and New Mexico at 7:00 am, <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<\/div>\n\n\n<p class=\"wp-block-paragraph\">The HRRR-UA WRF 12Z initialization (left) and observed (right) sounding for Phoenix at 5 am are shown below. There are two inversions on the observed sounding; the first inversion is at 510mb and is at the top of the boundary layer, and the second at 420mb is a subsidence inversion associated with the upper-level high pressure. Both initialization and observed soundings have precipitable water values near 32 mm (1.3&#8243;).<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"514\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-144-1024x514.png\" alt=\"\" class=\"wp-image-4693\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-144-1024x514.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-144-300x151.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-144-768x386.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-144-1536x771.png 1536w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-144.png 1577w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z (left) initialization and observed sounding (right) at Phoenix for 5 am this morning.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The observed sounding below is from Empalme (Guaymas), Mexico, and the inversion near 900mb is related to the Gulf Surge. Surface dewpoint temperature at Hermosillo increased about 10 degrees over 24 hours. Temperatures should easily reach convective temperatures this afternoon at Hermosillo, helping create an MCS that would reinforce\u00a0the\u00a0Gulf Surge. \u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"695\" height=\"792\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-145.png\" alt=\"\" class=\"wp-image-4694\" style=\"aspect-ratio:0.877521613832853;width:575px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-145.png 695w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-145-263x300.png 263w\" sizes=\"auto, (max-width: 695px) 100vw, 695px\" \/><figcaption class=\"wp-element-caption\">Observed sounding at Empalme, Mexico from 5 am this morning.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">At 250mb, the TUTT low is further west (south of El Paso)\u00a0than indicated by the analysis that feeds forecast initialization. The TUTT is located along the trough axis (red dash) that extends from Oklahoma\u00a0southwest to the TUTT low, then southeast from there to the TUTT low south of Brownsville. This trough cuts in two the subtropical monsoon ridge reforming in Texas and the one west of the Baja Peninsula.\u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"838\" height=\"853\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-085655.png\" alt=\"\" class=\"wp-image-4695\" style=\"aspect-ratio:0.9824024483550114;width:604px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-085655.png 838w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-085655-295x300.png 295w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-085655-768x782.png 768w\" sizes=\"auto, (max-width: 838px) 100vw, 838px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">At 500mb, the monsoon ridge is trying to get back to the Four Corners, and this morning it is just south of San Diego, with another ridge center in Texas. While the ridge rebuilds over Arizona and New Mexico, the TUTT low southwest of El Paso will combine with circulation from the\u00a0thunderstorm complex in Mexico last night and continue moving west. This will change the wind direction aloft in Arizona from northeasterly to easterly.\u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"846\" height=\"850\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-092615.png\" alt=\"\" class=\"wp-image-4700\" style=\"aspect-ratio:0.9952999627555135;width:608px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-092615.png 846w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-092615-300x300.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-092615-150x150.png 150w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-092615-768x772.png 768w\" sizes=\"auto, (max-width: 846px) 100vw, 846px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The monsoon ridge is elongated from central Arizona to north central Texas, at 700 mb. The inverted trough (red dash) will continue moving west and help initiate the MCS south of Douglas and Nogales.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"848\" height=\"851\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-093259.png\" alt=\"\" class=\"wp-image-4701\" style=\"aspect-ratio:0.9964806736809911;width:606px;height:auto\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-093259.png 848w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-093259-300x300.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-093259-150x150.png 150w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-093259-768x771.png 768w\" sizes=\"auto, (max-width: 848px) 100vw, 848px\" \/><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">Today<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">It\u2019s difficult to find any Convective Available Potential Energy (CAPE) on either forecast sounding, Tucson at 3 pm (left) and Nogales at 5 pm (right).\u00a0The strong inversion at the top of the boundary layer at 500 mb is limiting the CAPE, indicating isolated mountain storms are more likely, with the valleys remaining dry.\u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"581\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-091155-1024x581.png\" alt=\"\" class=\"wp-image-4696\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-091155-1024x581.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-091155-300x170.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-091155-768x436.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-091155.png 1402w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z forecast soundings for Tucson at 3 pm (left) and Nogales at 5 pm (right).<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The forecast radar reflectivity for this afternoon shows only a few thunderstorms in the White Mountains and isolated from Tucson south into Mexico.&nbsp;No significant microbursts are expected, and any rainfall in the valleys will be light.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-video aligncenter\"><video height=\"752\" style=\"aspect-ratio: 1134 \/ 752;\" width=\"1134\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/20260818-1617-11.8992015.mp4\" playsinline><\/video><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z simulated radar reflectivity from 1 pm to 2 am.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Tomorrow<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Gulf Surge moisture is moving into southwest Arizona today. The Tucson sounding (below, left) for Wednesday afternoon at 2 pm shows the surge of moisture has moved into Tucson. The Phoenix sounding (below, right) does not show surge moisture, but thunderstorms may form along the outflow forecast for later in the day.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"580\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-095504-1024x580.png\" alt=\"\" class=\"wp-image-4707\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-095504-1024x580.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-095504-300x170.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-095504-768x435.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/Screenshot-2026-08-18-095504.png 1415w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z forecast soundings for Tucson tomorrow at 2 pm (left) and Phoenix at 5:30 pm (right).<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Tomorrow, thunderstorms form in the afternoon from Tucson west into central Pima County. These storms will bring high winds, blowing dust, and heavy rain, and they will arrive in Phoenix around 9 pm.\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-video aligncenter\"><video height=\"752\" style=\"aspect-ratio: 1134 \/ 752;\" width=\"1134\" autoplay controls loop muted src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/20260818-1638-50.9544401.mp4\" playsinline><\/video><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z simulated radar reflectivity tomorrow from 1 pm to 2:30 am.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The 10-meter wind speed forecast for tomorrow at 6:30 pm shows the type of outflow that will help initiate storms in the Phoenix area after 8 pm.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"676\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-147-1024x676.png\" alt=\"\" class=\"wp-image-4705\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-147-1024x676.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-147-300x198.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-147-768x507.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-147.png 1131w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z 10-meter wind speed tomorrow at 6:30 pm.<\/figcaption><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">Outlook<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Typically it\u2019s an up-day\/down-day pattern in monsoon season for Arizona, but the forecast shows another up day for Thursday. Surface moisture from the Gulf Surge will be recycled, with surface heating and convective temperatures as the potential limiting factors.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"677\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-149-1024x677.png\" alt=\"\" class=\"wp-image-4708\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-149-1024x677.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-149-300x198.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-149-768x508.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-149.png 1142w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">HRRR-UA WRF 12Z simulated radar reflectivity Thursday at 6 pm.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Long-range global model forecasts\u00a0show we\u2019re back to a more active monsoon pattern through to next week.\u00a0<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"824\" src=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-146-1024x824.png\" alt=\"\" class=\"wp-image-4699\" srcset=\"https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-146-1024x824.png 1024w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-146-300x241.png 300w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-146-768x618.png 768w, https:\/\/discussions.weather.arizona.edu\/wp-content\/uploads\/2026\/08\/image-146.png 1082w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Global Ensemble Forecast System (GEFS) ensemble forecasts of 2-meter temperature (top) and 3-hour accumulated precipitation (bottom), NCAR.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Discussion written by Pat Holbrook and Patrick Bunn<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Summary Upper-level water vapor satellite imagery shows the jet stream stretching from the Pacific to northern California, with a quasi-stationary low-pressure system off the West Coast. An upper-level low just south of El Paso is splitting the subtropical high in two. It will push an inverted trough east that will change the wind direction aloft &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":[8],"class_list":["post-4685","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-8"],"_links":{"self":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/4685","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=4685"}],"version-history":[{"count":11,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/4685\/revisions"}],"predecessor-version":[{"id":4715,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=\/wp\/v2\/posts\/4685\/revisions\/4715"}],"wp:attachment":[{"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4685"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4685"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/discussions.weather.arizona.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4685"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}