570 FXUS21 KWNC 021839 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT July 02 2026 SYNOPSIS: Rebuilding mid-level high pressure over parts of the western and central contiguous U.S. (CONUS) supports increased extreme heat risk from the Interior West into parts of the Great Plains throughout week-2, with a moderate risk identified for much of this area around the middle of the period. Further southeast, enhanced subtropical high pressure also enhances the extreme heat risk across the Gulf Coast, the Florida Peninsula, and the South Atlantic Coast. Meanwhile, surface low development and an accompanying heavy precipitation risk is possible early over the eastern Carolinas. Near the West Coast, strengthening pressure gradients are forecast, which increases the risk for episodes of high winds. HAZARDS Moderate risk of extreme heat across much of the Interior West and Great Plains, Sun-Wed, Jul 12-15. Slight risk of extreme heat across much of the Interior West, Rockies, Plains, Gulf Coast, and South Atlantic Coast, Fri-Thu, Jul 10-16. Slight risk of heavy precipitation for parts of the Mid-Atlantic and the Southeast, Fri-Sat, Jul 10-11. Slight risk of episodic high winds along and near the West Coast, Fri-Thu, Jul 10-16. DETAILED SUMMARY FOR SUNDAY JULY 05 - THURSDAY JULY 09: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR FRIDAY JULY 10 - THURSDAY JULY 16: Following a significant heat event that is forecast to affect much of the central and eastern CONUS during week-1, models favor a building, slowly-retrograding 500-hPa ridge by early week-2. Anomalously warm temperatures and potential extreme heat conditions are mainly favored along a mean ridge axis that become re-established over the central and western CONUS towards the middle of the period. Around the cusp of weeks 1 and 2 (Jul 9-10), much of the ridging is favored to deamplify temporarily. This is exemplified by both the GEFS and the European ensemble (ECENS), about the same as yesterday. However, this deamplification appears only temporary, as model solutions support a rebuilding mid-level ridge that drifts over the central and interior western CONUS towards the middle of week-2. The dynamical European model (ECMWF) is most bullish with this restrengthening and stronger than yesterday, featuring a 601 dm height field maximum over the eastern Four Corners around days 11-12 (Jul 13-14). The GEFS and European ensemble (ECENS) means are only slightly more muted, peaking at 597 and 598 dm, respectively, around this time. The pattern supports a slight risk of extreme heat throughout week-2 across a large part of the central and western CONUS, with a moderate risk of extreme heat during the middle of week-2, when models are in best agreement on the timing and location of the amplified mid-level ridge. The ECMWF forecasts daily highs peaking at 110 to 115 deg F in much of the California valleys, and near 120 deg F in parts of the Desert Southwest. The ECMWF forecasts temperatures approaching 110 deg F at times as far north as western South Dakota and the lower elevations of southeastern Washington, but other tools are not as robust in these areas, so the moderate risk area does not extend that far north. The largest mid-level height anomalies are forecast to be near the central Rockies around the middle of week-2, but this area of mostly higher elevations is at lower risk of temperatures reaching hazards criteria despite being well above normal. Across the lower latitudes, enhanced subtropical ridging near the Southeast and western Atlantic supports a slight risk of extreme heat throughout week-2 across the Gulf and South Atlantic Coasts. The Probabilistic Extremes Tool (PET) from the ECENS is considerably more robust with the heat signal than the PETs from the GEFS and the Canadian ensemble (CMCE) across the Florida Panhandle, peaking in the 40 to 60 percent range in the ECENS but generally the 20 to 40 percent range in the other PETs, and only for a couple days. This implies a slightly better chance for extreme heat in the Florida Peninsula than other parts of the Southeast, but a moderate risk area is not supported by a preponderance of the tools, so only a slight risk is posted. Still, internal heat guidance shows the combination of high temperatures and humidities could push heat indices above 105 deg F from the southern Plains to the South Atlantic Coast. Downstream of the anomalous ridging over the western and central CONUS, some degree of mid-level troughing is favored over the eastern CONUS north of the Gulf Coast region, where some ensemble members continue to support surface low development that could potentially affect parts of the south Atlantic coast early week-2. Overall, however, models are a little less indicative of this scenario than yesterday, and ensemble means are placing the heaviest precipitation off the south Atlantic coast. Enhanced precipitation is favored to accompany any developing surface low, which sufficiently increases the odds for heavy precipitation early week-2 to justify posting a slight risk across the eastern Carolinas during the first two days of the period (Jul 10-11). This is restricted farther to the east than yesterday. Across the Desert Southwest, the PETs all highlight some potential for above-normal precipitation across parts of the Southwest, but chances for totals to exceed hazards thresholds are limited. In addition, raw precipitation forecasts from the models keep amounts under an inch for week-2 as a whole. The signal for increased precipitation aligns well with the time models favor the peak strength of the reamplifying western CONUS ridge, and suggests a more active monsoonal circulation later in week-2. But the continued lack of robust support in the raw tools and PETs, no corresponding precipitation hazards are posted. Localized thunderstorms are still possible and this area will continue to be monitored for increases in model forecasts of precipitable water and rainfall totals. Surface high pressure development off the West Coast is expected to coincide with thermally- induced low pressure centered over the Southwest. The resulting pressure gradient increases the chances for episodes of high winds throughout week-2 over parts of the Far West from the western fringes of the area at increased risk of extreme heat to the Pacific Coast. The GEFS, ECENS, and CMCE PETs continue to indicate at least a 20 percent chance of wind speeds exceeding the 85th climatological percentile at various times and locations for the duration of week-2 in the affected areas, with the ECENS PET depicting odds exceeding 30 percent toward the middle of week-2 along central sections of the West Coast. Therefore, a slight risk of high winds remains posted across this region Jul 10-16. It should be noted that if there is a substantial increase in monsoonal moisture and precipitation, somewhat cooler temperatures would result, likely reducing the strength of the thermal low pressure and weakening the high wind potential. FORECASTER: Rich Tinker $$