FXUS02 KWNH 200801

PREEPD



Preliminary Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

400 AM EDT Fri Mar 20 2026



Valid 12Z Mon Mar 23 2026 - 12Z Fri Mar 27 2026



...Anomalous early season heat wave across the Southwest abating

somewhat early next week but may rebuild midweek...





...Overview...



The medium range period will feature an active northern stream,

supplied by a closed Gulf of Alaska low shedding lobes of shortwave

vorticity across downstream portions of the southern

Canada/northern CONUS. These transient waves will occasionally

erode ridging in the Northwest and generate precipitation.

Meanwhile, the predominant Western ridge will remain locked in over

the Southwest while gradually expanding into the Southeast next

week.





...Guidance/Predictability Assessment...



The latest guidance is in reasonably good agreement regarding the

evolution of the ridge across the Southern U.S. next week.

Uncertainty exists with respect to the timing and amplitude of the

shortwaves propagating through the northern tier of the U.S.. A

general model blend consisting of the non UKMET deterministic

guidance was used in the day 3 blend. A non Euro suite blend was

favored through the end of the period due, in parto to run-to-run

inconsistencies, some ensemble spread in the ECE, and a divergence

from the CMC/GFS suite consensus regarding the northern stream

evolution.





...Weather/Hazards Highlights...



The main story during the medium range period will be the

anomalous,and sometimes, record breaking heatwave in the West. A

prominant upper level ridge will support



Kebede





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







































$$