Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
Versions:
1
2
509 FXUS02 KWBC 012000 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Sun Mar 1 2026 Valid 12Z Wed Mar 04 2026 - 12Z Sun Mar 08 2026 ...Emerging East-Central U.S. Heavy Rainfall Pattern this week... ...Guidance/Predictability Assessment... Guidance uncertainty in the upcoming medium-range period begins primarily focused across the Plains and vicinity mid-later week. Recent GFS/GEFS continues to advertise a frontal wave to track northeastward across the Midwest. This solution remains more amplified than the rest of the dynamical solutions that dig energy more sharply through the West. The AI models favor a delayed amplification relative to the GFS/GEFS but they have come into better agreement today. The ECMWF remains the least amplified guidance regarding this wave. Thereafter, another upper-level trough/wave is now more uniformly forecast in guidance to dig more through the West to the Southwest/Baja next weekend, but also allow for renewed Gulf return flow downstream in channeled flow on the western to northern periphery of a building/warming Southwest U.S./Atlantic upper trough. This will set another stage for the next bout of high QPF into next weekend from the south-central Plains to the Midwest in a region having just experienced widespread rainfall/convection. ...Weather/Hazards Highlights... A pronounced split upper flow pattern will dominate the nation this week. A leading southern stream upper trough and surface system will eject from the south-central U.S. through the Midwest then Northeast mid-late week and return inflow will fuel an emerging area of moderate to heavy rains/convection under a favorable upper jet. The Day 4 & 5 (Wednesday/Thursday) WPC Excessive Rainfall Marginal threat areas were reduced given the focus of highest QPFs is now across the southern Plains to the Mid-Mississippi Valley based on the latest from guidance. Overrunning moisture into cold Canadian high pressure sliding into the U.S. northern tier as driven by more progressive northern stream energies should also support a swath of snow from northern portions of the Upper Midwest/Great Lakes to the Interior Northeast where conditions may also support an icy transition zone to monitor. Meanwhile upstream, an amplified upper trough will dig sharply southeastward into the West from the Pacific Northwest to the Southwest/Rockies Wednesday-Friday and bring unsettled and cooling flow along with a widespread moderate precipitation focus from the Pacific Northwest through the north-central Intermountain/Rockies to include terrain enhanced snows. While recent guidance trends dig an increasing southern stream detached upper low/trough through the Southwest into Baja next weekend, downstream energy translation should also act to renew the wet/convective flow pattern next weekend again over the south-central U.S. to Midwest to monitor for runoff issues given ample earlier rainfall to moisten soils. Additional flow from the northeast Pacific may also work back into the Northwest to renew moderate precipitation next weekend and continued northern stream energy translation into cyclonic upper flow downstream into the northern tier could also allow for some cooler airmass intrusions to interact with the northern fringe of the aforementioned expanding southern stream precipitation area. In this pattern, amplified Southeast/Atlantic upper ridging and significant springtime warming will build and linger up the East Coast through later next week/weekend as lead cold damned high pressure moderates and loses southward influence. Kong/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 $$