879 FXUS21 KWNC 011839 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT July 01 2026 SYNOPSIS: Rebuilding mid-level high pressure over parts of the western and central contiguous U.S. (CONUS) supports above-normal summertime temperatures with an increased heat risk extending from the southwestern U.S. into the upper Midwest during week-2. Further south, enhanced subtropical high pressure also favors the potential for extreme heat conditions for parts of eastern Gulf of America coast during the period. Surface low development and an accompanying heavy precipitation risk remains favored over parts of the Southeast and Mid-Atlantic. Over the West Coast, strengthening pressure gradients favored leads to increased chances for episodes of high winds across the Pacific Northwest and California for much of the period. HAZARDS Slight risk of extreme heat across much of the Great Basin, Northern Intermountain, Rockies, Southwest, and Great Plains, Thu-Wed, Jul 9-15. Slight risk of extreme heat for the eastern Gulf Coast and Florida Peninsula, Thu-Wed, Jul 9-15. Slight risk of heavy precipitation for parts of the Mid-Atlantic and the Southeast, Thu-Sat, Jul 9-11. Slight risk of episodic high winds for portions of California and the Pacific Northwest, Thu-Wed, Jul 9-15. DETAILED SUMMARY FOR SATURDAY JULY 04 - WEDNESDAY JULY 08: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR THURSDAY JULY 09 - WEDNESDAY JULY 15: Following a significant heat event that is forecast to affect much of the central and eastern CONUS during week-1, models have been consistent in favoring a retrograding 500-hPa ridge by early next week. Anomalously warm temperatures and potential extreme heat conditions are mainly favored along a mean ridge axis that become established over the western and northcentral CONUS towards the middle of next week. Heading into the week-2 period (Jul 9-10), much of the ridging is favored to deamplify, where both the GEFS and ECMWF ensembles show a weaker mean solution of this mid-level feature compared to yesterday. However, this deamplification looks to only be temporary, as there is growing model support for a rebuilding ridge across the Interior West towards the middle of week-2. The ECMWF appears most bullish with this restrengthening, and features a mean 597 dm height field peaking over the eastern Four Corners on days 12-13 (Jul 13-14). The pattern reamplification and potential renewal of heat is noteworthy, as not often anomalies of this magnitude are evident at these longer leads due to ensemble spread. Across the lower latitudes, enhanced subtropical ridging over the Gulf of America and western Atlantic looks to remain a factor in the outlook. Consistent with the evolution of mid-level ridge further north over the Interior West, a reamplification is depicted in the ensemble guidance where coupled with anomalously warm sea surface temperatures in the eastern Gulf, this favors more persistence of above-normal temperatures and heat risks over parts of the Southeast throughout week-2. Due to the varying strength of the 500-hPa ridge favored during the period, there is more reliance on the raw temperature tools in the updated outlook, as these tools appear to show a more consistent response to the evolving pattern aloft compared to the calibrated guidance. With the ridge axis remaining in a fairly stable position during the period, a slight risk of extreme heat remains posted from the southwestern CONUS northeastward to the Upper Midwest but is now valid for all of week-2 to capture fluctuations in anomalous temperatures and accompanying heat risks. Relatively cooler daytime temperatures and decreased heat risks are possible within the highlighted area as the ridge deamplifies early in the period, which is best supported by low chances for daytime temperatures exceeding the 85th percentile in the ECMWF PET. Over time, both the GEFS and ECMWF PETs come into better agreement favoring remerging warm signals with 20-30% chances of maximum temperature exceeding the 85th percentile over the Interior West, as well as in the raw tools depicting higher temperature exceedance signals by days 10 and 11 (Jul 11-12) with probabilities supportive of the slight risk. Should the models show good continuity in maintaining the very strong mid-level height departures (as advertised by the ECMWF late in week-2) over the Interior West in the coming days, higher risk designations of extreme heat (including moderate and high risks) are likely to be added in upcoming outlooks. The potential for a higher risk designation is also supported by models tendency to underestimate high temperatures over areas with antecedent dryness, where actual temperatures could end up being higher than favored. Tied to the more persistent enhanced subtropical ridging favored over the Gulf and western Atlantic, a slight risk of extreme heat is also posted over the eastern Gulf coast and Florida Peninsula and now valid for all of week-2. This risk is supported by the deterministic NBM depicting apparent temperatures above 100 deg F late next week, and the PETs indicating increased chances for daytime temperatures exceeding the 85th percentile throughout week-2. Very warm sea surface temperatures in the eastern Gulf, with anomalies registering upwards of 1.5 to 2 deg C above normal. The NBM also continues to show a number of locations with very warm nighttime lows approaching and/or breaking records along the Gulf coast through late next week. Downstream of the anomalous ridging over the western and central CONUS, more mid-level troughing is favored over the eastern U.S. where there continues to be ensemble support for surface low development potentially affecting parts of the Southeast and Mid-Atlantic. Similar to yesterday, there are several low members featured over the lower eastern Seaboard and just offshore in western Atlantic which are also reflected in probabilistic ECMWF and Google AI tropical cyclone development tools. As is often the case with these types of lows forming near shore, there is high uncertainty as to whether any low that develops will acquire tropical characteristics, but such a realization cannot be ruled out. Regardless, enhanced precipitation is favored to accompany any developing surface low as PETs and raw tools continue to show increased chances for 3-day amounts exceeding the 85th percentile and 1 inch early in week-2. Therefore, a slight risk of heavy precipitation remains issued for parts of the Southeast and lower Mid-Atlantic, Jul 9-11. Within the highlighted slight risk area, any enhanced precipitation is expected to be welcome following the heat favored during week-1, though localized urban flooding is possible. Based on the PETs, elevated wind speeds are possible along the coastal Carolinas and Georgia, however the strongest winds are favored offshore and no corresponding wind hazard is posted. Across the Desert Southwest, the ECMWF PET shows a northward extension of the wet signal into the Great Basin, whereas the GEFS PETs maintains a more suppressed signal over western Mexico towards the middle of week-2. Despite this difference, the increase in percentile space well aligns with the time where models favor the reamplification of the ridge, and suggests a more active monsoonal circulation later in week-2. Due to the continued lack of support in the raw tools with both daily and 3-day mean totals remaining low, no corresponding precipitation hazards are posted. Localized thunderstorms are still possible and this area will continue to be monitored with ensemble guidance indicating precipitable water increasing during the week-2 period. Surface high pressure off the West Coast along with thermally induced low pressure over the Great Basin and Desert Southwest increase chances for episodes of high winds during week-2. The GEFS and ECMWF PETs continue to indicate at least a 20 percent chance of wind speeds exceeding the 85th climatological percentile. Therefore, a slight risk of high winds remains posted across this region, Jul 9-15. It should be noted that any substantial increase in monsoonal moisture and precipitation will bring cooler temperatures, which is likely to break down the thermal low pressure and weaken this high wind potential during the period. FORECASTER: Nick Novella $$