077 FXUS21 KWNC 141808 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT June 14 2026 SYNOPSIS: Mid-level high pressure is expected to increase chances for extreme heat from the Central Gulf Coast through Florida and the South Atlantic Coast into the middle of the period. Then, as conditions in the Southeast ease, mid-level high pressure is expected to build farther west in the second half of week-2, bringing the threat of extreme heat to the South-Central States, the Desert Southwest, and the California Central Valley. A surface front along the southern edge of unseasonably cool air is predicted early week-2 from the east-central Great Plains through much of the Middle Mississippi, Tennessee, and Ohio Valleys, enhancing chances for heavy precipitation there. HAZARDS Slight risk of extreme heat along the Central Gulf and South Atlantic Coasts, and the entire Florida Peninsula, Mon-Fri, Jun 22-26. Slight risk of extreme heat for much of the vicinity of the Southern Plains and Louisiana, Thu-Sun, Jun 25-28. Slight risk of extreme heat across the Desert Southwest and Central Valley of California, Thu-Sun, Jun 25-28. Slight risk of heavy precipitation for the east-central Plains, Middle Mississippi, Ohio, and Tennessee Valleys and adjacent areas, Mon-Tue, Jun 22-23. DETAILED SUMMARY FOR WEDNESDAY JUNE 17 - SUNDAY JUNE 21: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR MONDAY JUNE 22 - SUNDAY JUNE 28: Subtropical mid-level ridging is expected to extend into the Florida Peninsula and adjacent areas of the Central Gulf and southern Atlantic coasts through the middle of week-2, increasing the odds for extreme heat in those areas. Bias-corrected GEFS and ECENS Heat Index guidance for week-2 depicts values peaking near 105 deg F, and the National Blend of Models (NBM) predicts near-record or record high nighttime minimum temperatures of 76-80 deg F across much of the Florida Peninsula and a few nearby locations. Some locations on the Florida Keys may not drop below 85 deg F on one or more nights. The Probabilistic Extremes Tools (PETs) from the European ensemble (ECENS), Canadian ensemble (CMCE), and GEFS depict the best chances for high temperatures above the 85th climatological percentile across the Florida Peninsula (with the ECENS depicting 30 percent chances or greater). The slight risk of extreme heat continues through June 26th when most tools show the subtropical mid-level ridge flattening across the Southeast and emerging farther west. During the middle and latter parts of week-2, mid-level subtropical ridging is expected to emerge over the central and interior western CONUS, bringing an increased risk of extreme heat to much of the south-central CONUS along with much of the Desert Southwest and California's Central Valley. Internal skill-weighted guidance blending ECENS and GEFS output shows 40 to 60 percent chances for heat indices over 105 deg F across most of Louisiana, eastern Texas, the central tier of Oklahoma, and the lower Rio Grande Valley. This appears largely driven by unusually high humidity, as the PETs depict actual air temperatures remaining near or below 100 deg F with low chances of reaching the 85th climatological percentile. However, uncalibrated temperatures from the ECENS and GEFS show one or two incursions of unseasonably cool air moving into the south-central Plains and Lower Mississippi Valley, resulting in significant uncertainty in the temperature outlook. A slight risk of extreme heat is therefore designated for the southern High Plains, Texas, and Louisiana, June 25-28. Considerably above normal temperatures cover most of the interior West, including the Rockies, Intermountain West, and Northwest during the last half of week-2, but temperatures and heat indices are expected to remain below hazards thresholds. The PETs and internal heat index guidance from the ECENS and GEFS depict low chances for temperatures or heat indices to top 100 deg F in these areas. The building mid-level subtropical ridge also increases the chances for extreme heat in the Desert Southwest and the Central Valley of California during the latter half of week-2. The ECENS and GEFS PETs show a 20 to 30 percent chance of temperatures reaching 110 deg F in the Desert Southwest on some days during the second half of week-2, and comparable chances for highs topping out over 100 deg F in the California Central Valley. The same tools show 20 to 30 percent chances for temperatures exceeding the 85th climatological percentile. A frontal boundary (separating the heat in the Southeast from unseasonably cool air farther north) is expected to be draped from the east-central Great Plains eastward through most of the Middle Mississippi, Tennessee, and Ohio Valleys early week-2. This is expected to drive abundant precipitation and enhanced thunderstorm activity. The PETs indicate at least a 20% chance of 3-day precipitation exceeding the 85th climatological percentile. Uncalibrated ECENS output depicts a 30 to 60 percent chance for precipitation totals to exceed an inch during the first few days of the period throughout the slight risk area. Toward the middle of week-2, mid-level troughing and unusually cool surface air is expected to moderate and retract northeastward, weakening the frontal boundary and bringing an end to the heavy precipitation threat. Given this, a slight risk of heavy precipitation remains posted for portions of the east-central Plains, Middle Mississippi, Ohio, and Tennessee Valleys valid Jun 22-23. FORECASTER: Anthony Artusa $$