


Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
888 FXUS02 KWBC 072035 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 435 PM EDT Mon Jul 7 2025 Valid 12Z Thu Jul 10 2025 - 12Z Mon Jul 14 2025 ***Heavy rain and storms expected for the Midwest and portions of the East Coast, and high heat continues for the Southwest states*** ...Pattern Overview... A well defined upper level trough is forecast to track from southwestern Canada eastward to the northern Great Lakes for the end of the week and into the weekend. This will bring a cold front that will cross the central and northern Rockies, and then across the north-central U.S. to close out the work week. Meanwhile, a stationary frontal boundary will be idling across the Mid-Atlantic region with copious moisture to fuel daily showers and storms. A separate complex of organized convection is also likely for the upper Midwest Thursday into Friday ahead of the front. Upper level ridging continues over the Southwest states and this will lead to a continuation of the very hot conditions. ...Guidance/Predictability Assessment The 12Z model guidance starts off in excellent agreement across the Continental U.S. on Thursday, with a multi-deterministic model blend working well as a starting point in the forecast process. The models agree on a stronger shortwave trough and probable closed low over the Dakotas and Minnesota to close out the work week. The CMC is now more in line with the model consensus, and also fits in well with the AIFS guidance, so it was included through the end of the forecast period. Model differences become more pronounced with trailing shortwave energy across the western High Plains and into south-central Canada by Sunday and Monday. The ensemble means were gradually increased to about half by this time to account for the model differences. ...Weather/Hazards Highlights... Scattered convection anticipated to fire ahead of, and along progressive cold fronts, stalled boundaries and round the upper high in the Southern Rockies. The exact location of higher QPF is less certain however there is the potential for isolated instances of flash flooding-- including areas from the Corn Belt into the Midwest and Ohio Valley, Appalachians, Mid-Atlantic, and Northeast. In terms of the excessive rainfall outlooks, the broad Marginal Risk area is maintained across the Upper Midwest for both days 4 and 5. Upon examination of the 12Z model guidance suite, a small Slight Risk area has been introduced for extreme eastern Nebraska and west- central Iowa for Day 4. There is a good overall model signal for organized MCS activity to develop with the potential for 1+ inch per hour rainfall rates. Elsewhere, a broad Marginal Risk remains from interior portions of the Deep south to the southern Appalachians to the Mid-Atlantic coast, and a Slight Risk was also added for portions of central North Carolina into south-central Virginia for Day 4. This region will be south of a quasi-stationary front with copious moisture in place, and the combination of saturated grounds from both recent and short range predicted rainfall will increase the potential for flooding. Many locations will have daily maximums climbing well into the 100s at lower elevations across the Southwest and mainly dry conditions, except for perhaps far southeastern Arizona into New Mexico where some monsoonal moisture may be present. Experimental HeatRisk values may rise to Major or Extreme levels (3 out of 4 or 4 out of 4) from the California deserts into southern Nevada, Utah, and Arizona. Extreme Heat Watches have been raised for parts of Arizona through at least Thursday. Campbell/Hamrick Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$