335 FXUS21 KWNC 271836 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT July 27 2026 SYNOPSIS: Strong mid-level high pressure is forecast to bring a prolonged heat wave to the West through the beginning of August. Antecedent dryness along with the likelihood of above-normal temperatures and below-normal precipitation during the next two weeks supports an increased risk for the Rapid Onset of Drought to parts of the Great Plains and Corn Belt. A renewal of an enhanced monsoon during early August is possible following the prolonged heat wave. Possible surface lows forming in the lee of the Rockies may support periods of high winds across the Northern and Central Rockies at the beginning of the period, which may lead to enhanced wildfire risk where hot and dry conditions are anticipated. HAZARDS High risk of extreme heat for portions of the Great Basin, and adjacent regions, Tue-Thu, Aug 4-6. Moderate risk of extreme heat for portions of the Southern Plains, Southwest, Great Basin, Rockies, and California, Tue-Fri, Aug 4-7. Slight risk of extreme heat for most of the western two-thirds of the CONUS and Southeast U.S., Tue-Mon, Aug 4-10. Slight risk of extreme heat for the Middle and Upper Mississippi, and Ohio Valleys, Great Lakes, Mid-Atlantic, and Northeast, Tue-Thu, Aug 4-6. Slight risk of heavy precipitation for parts of the Desert Southwest, Tue-Mon, Aug 4-10. Slight risk of high winds for the Northern and Central Plains, Tue-Wed, Aug 4-5. Rapid onset drought (ROD) possible for parts of the Great Plains, Middle Mississippi Valley and Great Lakes. DETAILED SUMMARY FOR THURSDAY JULY 30 - MONDAY AUGUST 03: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR TUESDAY AUGUST 04 - MONDAY AUGUST 10: The GEFS, ECENS and CMCE are in good agreement and remain consistent in showing a highly amplified 500-hPa ridge peaking in strength by the middle of week-1 when it becomes centered over the western Contiguous U.S. (CONUS) before weakening towards the end of week-1. However, tools are now showing an increase in strength of the mid-level height anomaly moving into the middle of week-2. By day 10, the ECENS and CMCE support a near 600dm ridge over the West. The increase in strength of the ridge moving into the middle of week-2 supports a high risk (>60% chance) of extreme heat for portions of the Great Basin, Aug 4-6. A moderate risk (40-60% chance) is highlighted across portions of the Southern Plains, Southwest, Great Basin, Rockies, and California, Aug 4-7. The moderate risk is spatially reduced relative to yesterday with much of the Southern Plains and lower elevations of the Desert Southwest removed from the risk area today. A slight risk (20-40% chance) is designated for most of the western two-thirds of the CONUS and Florida. Heat tools indicate greater than 30-40% chances of actual temperatures or heat index values exceeding 110 deg F across parts of the Desert Southwest and California Central Valley and 100 deg F across portions of the Great Basin. The National Blend of Models indicates near or record daily highs for parts of the southwestern CONUS at the beginning of week-2, as well as near to record nighttime lows across the southern tier of the CONUS, providing little to no relief in these areas. Surface low formation in the lee of the Rockies may help to propel a front across the Plains and into the Great Lakes. Ahead of this system, warm moist air from the Gulf of America may bring another round of extreme heat to portions of the Upper Mississippi Valley, Great Lakes, Ohio Valley and into the Northeast and Mid-Atlantic and adjacent areas. Therefore, an additional slight risk of extreme heat is posted for these regions for Aug 4-6. Based on the evolving mid-level pattern, this is likely to be a more transient heat wave relative to the extreme heat ongoing this week. These surface lows may bring enhanced winds to the region. A slight risk of high winds is designated across the Northern and Central Plains, Aug 4-5, where wind gusts could exceed 34 kts (~39 mph). Gusty conditions combined with hot, dry weather may enhance wildfire risk for some of these areas. According to the U.S. Drought Monitor valid July 21, abnormal dryness (D0) and moderate drought (D1) expanded this past week across the Dakotas where a Rapid Onset Drought (ROD) risk is underway. Increasing 30-day precipitation deficits, high evapotranspiration rates, and the increased chance of above-normal temperatures and below-normal precipitation during the next two weeks support an enhanced risk of ROD across even more of the Great Plains and Corn Belt. With extreme heat ongoing over the Southwest, and favored to continue through much of the next 10 days, thermal low formation over the region, plus a favorable location for the mid-level ridge as it weakens, would support a resurgence of the Southwest Monsoon early in August. Above normal precipitable water is favored over the Southwest by middle of week-2. Therefore, a temporally broad slight risk of heavy precipitation is forecast over parts of the Southwest, for all of week-2. FORECASTER: Ryan Bolt $$