Forecast Discussion
— ExtendedGuidance/Predictability Assessment
Guidance uncertainty in the upcoming medium-range period begins primarily focused across the Plains and vicinity mid-later week. Recent GFS/GEFS runs swing a shortwave aloft and then brings an amplified frontal wave northeastward into the Midwest. This solution still seems too amplified compared with the rest of the dynamical guidance that dig energy more sharply through the West. The AI models also favor a delayed amplification relative to the GFS/GEFS. Thereafter, another upper-level trough/wave is now more uniformly forecast in guidance with 00 UTC Canadian model favorable trend toward the rest of 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. Elongated Day 4/5 (Wednesday/Thursday) WPC Excessive Rainfall Marginal threat areas are in place from the southern Plains through the Mid-MS and central Ohio Valley states given pooling moisture and repeat potential. Moisture overrun into cold Canadian high pressure skimming 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 detatched 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 loses southward influence.
Schichtel
Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at:
000 FXUS02 KWBC 010820 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 320 AM 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 runs swing a shortwave aloft and then brings an amplified frontal wave northeastward into the Midwest. This solution still seems too amplified compared with the rest of the dynamical guidance that dig energy more sharply through the West. The AI models also favor a delayed amplification relative to the GFS/GEFS. Thereafter, another upper-level trough/wave is now more uniformly forecast in guidance with 00 UTC Canadian model favorable trend toward the rest of 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. Elongated Day 4/5 (Wednesday/Thursday) WPC Excessive Rainfall Marginal threat areas are in place from the southern Plains through the Mid-MS and central Ohio Valley states given pooling moisture and repeat potential. Moisture overrun into cold Canadian high pressure skimming 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 detatched 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 loses southward influence. 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 $$