Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
563 FXUS02 KWBC 301844 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 244 PM EDT Mon Jun 30 2025 Valid 12Z Thu Jul 03 2025 - 12Z Mon Jul 07 2025 ...Multi-day Heavy Rain/Flash flooding threat for Florida... ...Southwest U.S. to Southern Rockies/High Plains monsoonal rains as the tropics activate over the eastern Pacific and the Gulf... ...Northern Plains/Upper Midwest Heavy Convection/Rain threat... ...Guidance/Predictability Assessment... The latest suite of guidance is in good agreement, remaining fairly clustered into the weekend. For the weekend and beyond solution diverge on energy streaming the Pacific to the West Coast and points inland. This variances play a role in how much the ridge over the central U.S. will erode with multiple impulses riding the top of the ridge. There continues to be a persistent signal for increasing monsoonal moisture to the Southwest thanks to Tropical Cyclone Flossie in the East Pacific near Mexico and T.D. Barry out from the Gulf. Additionally, some of the models are suggesting leftover Gulf low pressure from a weakening frontal boundary out from the Southeast U.S. may impact the Florida Peninsula by the end of the week/weekend. The National Hurricane Center continues to monitor this feature. Given above average clustering, a multi-model approach was used for the first half of the extended periods before including the ensemble means. The tail end of the forecast was comprised mainly by the means. ...Weather/Hazards Highlights... Thunderstorms with deep moisture/instability will bring heavy convective downpours ahead of a upper trough and surface front into late week for the far Southeast U.S./Florida where WPC Excessive Rainfall Outlook (ERO) Marginal Risk areas exist Day 4/Thursday and Day 5/Friday. A focus for multi-day heavy rains may work to Gulf coastal central Florida where a Slight Risk area continues for Day 4/Thursday and Day 5/Friday given precursor rains and heavy rainfall potential given initial right entrance region upper jet support and anomalous Gulf tropical moisture. Focus may shift slowly southward over Florida over the weekend. Monsoonal moisture with some connection to eastern Pacific (T.S. Flossie) and Bay of Campeche (T.D. Barry) tropical features is anticipated to increase spatially which in turn should boost potential rain amounts across the Southwest, Southern Rockies/adjacent High Plains and locations along the western periphery of a warming central U.S. upper ridge. An ERO Marginal Risk area was maintained there for Day 4/Thursday, slowly shifting focus to the far southern High Plains Day 5/Friday. Areas like the Sacramento Mountains, where the steep terrain and burn scars cause the area to be particularly sensitive to rain and most vulnerable to potential flash flooding, especially with wet antecedent conditions there. Elsewhere, periodic afternoon and nocturnal strong to severe storms/MCS activity offer heavy rain/runoff potential to focus over the north-central Plains and Upper Midwest late week into Saturday as upper trough/impulse energies work over the northern periphery of the main central U.S. upper ridge as moisture/instability pools near wavy passing and draping fronts. WPC ERO Marginal Risk areas have been introduced for Day 4/Thursday and Day 5/Friday. Weekend to early next week activity with upper system/frontal progressions then work over the central Midwest/Great Lakes and the Northeast. Campbell/Schichtel 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 $$