FXUS02 KWBC 200833

PMDEPD



Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

433 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 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 by mid-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 part, 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 potentially, record breaking heatwave in the West. A

prominent upper-level ridge will support maximum temperatures that

are 20-40 degrees above average from the Southwest to Great 

Plains. Widespread maximum and minimum temperature records are 

expected from the Southwest early next week to the Central U.S. by 

midweek. This heatwave, combined with dry conditions, will 

contribute to fire weather concerns over portions of the Northern 

High Plains, Central Rockies and Southern Plains early next week. A

critical threat (70% chance) of strong winds, low relative 

humidity and warm temperatures will be in place over the 

aforementioned areas.



A potent mid-latitude cyclone will move from the Northwest to the

Canadian Maritime next week. This system will bring moderate to

heavy rain over the Pacific Northwest Tuesday. Most of the

precipitation from this will be in the form or rain since the

shortwave aloft will be embedded within the broader Western ridge.

Higher elevations of the Olympic and Cascade mountains will 

receive some snowfall, especially on the backside of the associated

cold front. The low pressure system will weaken while it tracks 

across the Central U.S., before reinvigorating over the East and 

producing some rain/snow for parts of the Great Lakes and Northeast

by late next week.





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











































$$