Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
374 FXUS02 KWBC 151959 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Mon Jun 15 2026 Valid 12Z Thu Jun 18 2026 - 12Z Mon Jun 22 2026 ...Significant Excessive Rainfall/Flooding Threat for the Gulf Coast States and Southeast Thursday through Friday... ...Pattern Overview and Guidance/Predictability Assessment... An amplified pattern of troughing over the Northeast and ridging out west becomes more zonal by this weekend. A tropical feature along the Texas Coast shifting into the Southeast occurs south with a central states low this weekend. NHC has increased its probability of tropical development along the Texas Coast to 50%. There remains uncertainty with this low and its track inland later this week. The EC remains the slowest solution while the EC-AIFS seems to be a decent middle ground between the faster UKMET/CMC and weaker GFS. The Day 3-7 progs were based on a generally model blend favoring the 06Z AIFS where manually possible. QPF has updated 13Z NBM with the 06Z AIFS/GFS and some EC this weekend over the North-central states. ...Weather/Hazards Highlights... A wave of tropical origin lifts up the Texas coast midweek, tracking over the Southeast through Friday as it interacts with an existing frontal boundary. Deep tropical moisture influx and instability will surge in from the coast a fuel a notable excessive rainfall/flash flooding threat into at least Friday. The ECMWF remains the slowest solution, so timing and uncertainty persist with this feature. Please see the Excessive Rainfall Discussion (ERD) and hazards chart (both are linked below) for further details on the Moderate Risk on Day 4 and lingering risks from Texas to the Southeast for Day 5. This weekend, a Colorado low looks to form and track over the Central Plains to the Great Lakes. Abundant moisture streaming into this system should lead to sizable areas of heavy rain that shift east/southeast with time. West Coast ridging keeps temperatures 10-20 degrees above normal over the Northwest/northern Intermountain West through Friday with a northern stream low over BC breaking down the ridge a bit over the weekend. Ridging looks to return to the West Coast early next week. Otherwise, somewhat normal summer temperatures are expected across CONUS, though the tropical moisture along the Gulf Coast will maintain high nighttime temperatures, making for a heat wave over the Florida Peninsula and portions of the Gulf Coast. Jackson 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, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages are at: 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 $$