Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
102 AM EDT Mon Jul 22 2019
Valid 12Z Thu Jul 25 2019 - 12Z Mon Jul 29 2019
...Overview and Guidance/Predictability Assessment...
The models continue to show deamplification of the eastern US
trough next weekend into early next week, with persistent upper
ridging centered across the Four Corners region/Southwest and
developing over Florida. Mid level waves and associated surface
fronts traverse the northern tier from the Pacific northwest to
the upper Great Lakes.
The mid week front stalls as it crosses from the Florida
Panhandle/northern Peninsula to South Texas. The front decays next
weekend. Farther west, shortwave energy should move a cold front
across the northern Great Basin/northern Rockies, reaching the
northern High Plains by day 3 (Thu) and 4 (Fri). This fronts
decays as the parent low pressure departs into central Canada.
Additional shortwave energy is expected to reach the Pacific
Northwest next weekend and deamplify as it moves inland across the
northern Rockies and Plains next Sun and Mon 29 Jul.
Deterministic and ensemble solutions showed sufficient consensus
during days 3-7 to use a multi-model blend (12Z ECMWF/ECMWF
Ensemble mean/18z GFS/18z GFS Ensemble mean/12 Canadian global/12z
UKMET).
...Weather Highlights/Threats...
The frontal boundary off the Eastern Seaboard into the Gulf of
Mexico is expected to focus areas of showers and thunderstorms
from the eastern Gulf coast to Florida.
The shortwave/frontal system moving from the Pacific Northwest to
the Northern Plains/Upper Midwest should bring an increase in
shower/storm chances to the Upper Midwest by late week and across
the Great Lakes next weekend and Mon 29 Jul.
Meanwhile, daily scattered storms will be possible across the
central/southern Rockies as some monsoonal moisture manages to
spread into the upper ridge.
Temperatures across the central and eastern US are expected to
gradually moderate back to normal towards the end of the week.
Areas of temperatures 5-10 degrees above normal developing from
the central Plains to the lower Great Lakes and northeast Sun 28
Jul and Mon 29 Jul as heights/temperatures aloft in the Ensemble
Means climb to above normal values. Temperatures cool to slightly
below normal values next Sun 28 Jul to Mon 29 Jul in the northern
Rockies to high Plains.
Petersen
Additional 3-7 Day Hazards information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, winter weather outlook probabilities
and heat indices are at:
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/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml