Extended Forecast Discussion NWS Weather Prediction Center College Park MD 158 AM EST Sat Mar 1 2025 Valid 12Z Tue Mar 04 2025 - 12Z Sat Mar 08 2025 ...Numerous severe thunderstorms and heavy rainfall expected from eastern Texas to the Deep South states midweek... ...General Overview... The weather pattern across the continental U.S. will be quite active next week with two big storm systems of interest. The first and strongest low pressure system will be gathering strength across the central Plains on Tuesday in response to an amplifying upper level shortwave exiting the Rockies. Heavy rainfall, severe thunderstorms, and strong winds will be making weather headlines across the south-central U.S. through midweek, and the storm system reaches the East Coast by Wednesday night. A second and slightly weaker storm system develops over the Rockies on Thursday and likely reaches the central Plains on Friday, with additional showers and thunderstorms expected. This should reach the East Coast states by next Saturday as the flow pattern aloft remains rather progressive. ...Guidance/Predictability Assessment... The 00Z model guidance suite is in good overall synoptic scale agreement across most of the continental U.S., and has consolidated well regarding the track and intensity of the mid-week storm system. However, there are more question marks with the second storm behind it, with the models varying more beyond Friday morning as the system crosses the south-central states. This WPC medium range product suite was primarily produced from a broad composite of the deterministic guidance and ensembles along with the National Blend of Models, with the ensemble means increased to about half by Saturday. ...Weather/Hazards Highlights... An amplified upper level trough reaches the western High Plains by Tuesday morning, along with a rapidly developing surface low that will track eastward across the Midwest and then across the Great Lakes. Abundant Gulf moisture and instability will be advected northward to fuel widespread heavy rainfall from the southern Plains to the eastern U.S. through early Thursday. The latest guidance continues to signal the heaviest rainfall totals from the ArkLaTex to the western Ohio Valley on Tuesday/Tuesday night. Some areas have wet antecedent soil conditions, which would exacerbate flood potential. The Slight Risk area is maintained on the Day 4 excessive rainfall outlook across Arkansas and southern Missouri, and a new Slight Risk area will be added for portions of southern Iowa and northern Missouri. Once this storm system reaches the Northeast U.S. Wednesday, a Marginal Risk is planned for the new Day 5 outlook from New Jersey to southern Maine where 1-2 inches of rainfall is likely. Another facet of this low pressure system will be the elevated potential for widespread severe weather from eastern Texas to the lower Mississippi River Valley through Tuesday night. A favorable combination of kinematics and deep moisture increases the threat of damaging winds, large hail, and tornadoes. The Storm Prediction Center has additional information pertaining to this. A second storm system is expected to follow behind this, and bring additional rounds of showers and thunderstorms to many of these same areas, but the current thinking is that it will not be as intense as the midweek storm system. Some strong to severe thunderstorms will also be possible with this event late in the week, depending on how low level boundaries evolve. 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