Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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656 FXUS21 KWNC 291813 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT May 29 2026 SYNOPSIS: Today`s primary hazard concern is the increased potential of extreme heat and Rapid Onset Drought (ROD) across parts of the central and east-central contiguous U.S. (CONUS) associated with strong mid-level high pressure across these regions. An area of mid-level low pressure is forecast to move into the western CONUS early in week-2. This may bring episodes of high winds to parts of the West. HAZARDS Moderate risk of extreme heat across parts of the Northern and Central Plains, Upper and Middle Mississippi Valley, and Great Lakes region, Sat-Sun, June 6-7. Slight risk of extreme heat for portions of the Northern and Central Plains, Upper and Middle Mississippi and Ohio Valleys, and Great Lakes region, Sat-Fri, June 6-12. Slight risk of high winds for parts of the West, Sat-Mon, June 6-8. Possible Rapid Onset Drought for parts of the Upper and Middle Mississippi Valley and Great Lakes region. DETAILED SUMMARY FOR MONDAY JUNE 01 - FRIDAY JUNE 05: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SATURDAY JUNE 06 - FRIDAY JUNE 12: A mid-level ridge across the West at the end of week-1 is anticipated to shift eastward to the central CONUS early in week-2, with multiple model ensemble means indicating this ridge amplifying across the central CONUS. Recent deterministic GFS and ECMWF model solutions indicate positive 500 hPa height normalized anomalies reaching greater than 3 standard deviations across the Northern Plains and Upper Mississippi Valley early in the period. This pattern amplification translates to increased signals for heat across the north-central CONUS in the model solutions and associated tools. Therefore a moderate risk (40-60% chance) of extreme heat is designated for parts of the Northern and Central Plains, Upper and Middle Mississippi Valley, and Great Lakes region, June 6-7. The PETs indicate at least a 20 to 30% chance of temperatures exceeding the 85th percentile climatologically and 90 deg F (85 deg F across more northern regions), with uncalibrated guidance indicating areas further north exceeding 90 deg F. A broader area of slight risk is highlighted for these regions in addition to the Ohio Valley, June 6-12. Southerly enhanced moist flow is possible as surface high pressure forms across the East, resulting in higher relative humidity which could result in higher heat index temperatures across the risk area. Recent model guidance shows 2-m dewpoint temperatures reaching the 70s (deg F) in the extreme temperature risk areas. Following a very wet spring across the Great Lakes and Upper Mississippi Valley, precipitation has been limited over the past several weeks. The most recent release of the U.S. Drought Monitor shows expansion of abnormally dry conditions across parts of the region. WPC`s week-1 forecast indicates below normal precipitation and above normal temperatures in this area. Above normal temperatures are forecast to continue into week-2 and near to below normal precipitation is favored as well. Therefore, a possible risk of ROD is posted for parts of the Upper and Middle Mississippi Valley and Great Lakes region. As the 500-hPa positive height anomalies progress eastward at the start of week-2, an area of mid-level troughing is forecast to develop near the West Coast. This system brings elevated chances for high winds to much of the West Coast and into the Great Basin. There is broad support for winds exceeding the 85th climatological percentile across this area and uncalibrated guidance also highlights elevated winds early in week-2 as this feature moves into the region. Therefore, a slight risk of high winds is posted for these regions June 6-8. In Alaska, river ice breakup season is ending, but many rivers north of the Brooks Range remain icebound. River breakup flooding can occur with little or no notice as conditions on frozen rivers can change quickly, so please check with the Alaska Pacific River Forecast Center for the latest conditions and advisories. FORECASTER: Ryan Bolt $$