Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
109 AM EDT Fri Aug 07 2020
Valid 12Z Mon Aug 10 2020 - 12Z Fri Aug 14 2020
...Overview and Guidance/Predictability Assessment...
Guidance reasonably agrees that two closed upper lows will track
eastward over Canada as trough energies and moderating/convection
focusing fronts work over the northern half of the U.S..
Underneath, hot upper ridging will prevail over the southern half
of our nation.
The WPC medium range product suite was mainly derived from a
composite of well clustered guidance from the
GFS/ECMWF/UKMET/Canadian days 3-5/Mon-Wed in a pattern with above
normal predictability. Forecast spread growth and flow continuity
favors a transition into day 7/Fri to the ECMWF ensemble mean
along with continued usage of the National Blend of Models.
...Weather/Hazard Highlights...
Episodes of strong to severe thunderstorms are likely from the
n-central U.S. to the East. The most prominent focus for
convection will be with a cold front working into above normal
lead heat from the Midwest to the Northeast/Mid-Atlantic Mon-Wed.
The stalling front trailing back through the north-central states
will remain a convective focus next week as impulses eject from a
moderating upper trough set to dig into the Northwest.
Meanwhile, the Southeast/Florida will see diurnal convection of
varying intensity, with a weakening front over the Southeast
providing an added focus early in the period. Within the broad
area of shower/thunderstorm potential there will likely be areas
of heavy rainfall.
Schichtel
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