580 FXUS21 KWNC 151833 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT June 15 2026 SYNOPSIS: Persistent above-normal mid-level pressure over the western and southern Contiguous U.S. (CONUS) favor unseasonably warm temperatures across the West and along the Gulf Coast, potentially resulting in extreme heat for many locations. A nearly stationary area of mid-level low pressure over the Great Lakes is favored to produce several rounds of precipitation across the central and eastern CONUS, some of which could reach hazardous criteria. HAZARDS Slight risk of extreme heat for Florida and adjacent regions, Tue-Mon, Jun 23-29. Slight risk of extreme heat for much of Texas, the Desert Southwest, and the Central Valley, Tue-Mon, Jun 23-29. Slight risk of extreme heat for the Interior Northwest, Tue-Mon, Jun 23-29. Slight risk of heavy precipitation for the Middle Mississippi, Tennessee, and Lower Ohio Valleys as well as eastern portions of the Southern and Central Plains, Tue-Wed, Jun 23-24. DETAILED SUMMARY FOR THURSDAY JUNE 18 - MONDAY JUNE 22: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR TUESDAY JUNE 23 - MONDAY JUNE 29: Multiple model ensembles continue to depict a mostly stationary pattern across North America during the week-2 period, with ridging over the western CONUS and troughing over the Great Lakes. This pattern is likely to result in unseasonably warm temperatures across the West and bring potentially extreme heat along the U.S.-Mexico border, as well as most of Texas and the Central Valley of California. The Probabilistic Extremes Tools (PETs) from multiple ensembles indicate at least a 20% chance of maximum temperatures exceeding 100F along the Rio Grande and in the Central Valley of California, and 110F for the Mojave Desert. Temperatures are not expected to get quite as high for central Texas but very high dewpoints are likely, the result of robust inflow of Gulf moisture throughout the forecast period. Therefore a slight risk of extreme heat is posted for these regions, valid for all of week-2 (Jun 23-29). Further north the PETs indicate at least a 20% chance of maximum temperatures to exceed 95F for interior Washington and Oregon, as well as the lower Snake River Valley. While humidity is not likely to be much of a factor, this is well above the 85th climatological percentile and within heat criteria for the region, therefore a slight risk of extreme heat is issued for this region, also for all of week-2. Enhanced subtropical ridging over the western Atlantic and Greater Antilles is indicated by multiple ensembles, favoring above-normal temperatures for Florida. Like the other synoptic features highlighted, models favor this enhanced riding to remain in place throughout the week, resulting in higher temperatures. While maximum actual temperatures are not that large, very high humidity has the potential to push apparent temperatures into hazardous criteria. Additionally, record to near-record high minimum temperatures are indicated by the National Blend of Models, bringing very little relief from heat effects during overnight hours. Given all this, a slight risk of extreme heat is posted for all of Florida and adjacent areas, once again valid for the whole week-2 forecast period. Meanwhile, persistent troughing over the Great Lakes is favored to develop one or more frontal boundaries and push areas of rain across the central and eastern CONUS. Model spread is quite high regarding the extent, timing, and duration of resultant precipitation, however the Middle Mississippi and Lower Ohio Valleys are where models show the most agreement. Multiple PETs indicate the potential for 3-day rainfall totals to exceed the 85th percentile and at least 1 inch early in week-2, with uncalibrated daily probabilities of precipitation from the GEFS and ECENS targeting the first two days of the forecast period in particular. This increased concurrence among the models, along with synoptic pattern recognition warrants a continuation of a slight risk of heavy precipitation for the Middle Mississippi, Tennessee, and Lower Ohio Valleys as well as eastern portions of the Southern and Central Plains, covering the period Jun 23-24. FORECASTER: Danny Barandiaran $$