Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
231 AM EDT Sat Jun 19 2021
Valid 12Z Tue Jun 22 2021 - 12Z Sat Jun 26 2021
...Heat intensifies from the interior Northwest to the Plains next
week...
...Guidance/Predictability Evaluation...
A composite blend of well clustered model solutions of the 18 UTC
GFS and 12 UTC ECMWF/UKMET/Canadian seem to offer a good basis for
the day 3-5 (Tuesday-Thursday) forecast period in a pattern with
above average continuity and predictability. Model continuity
begins to suffer into days 6/7 and the WPC product suite was
instead mainly derived from still compatible GEFS/NAEFS/ECENS
means and National Blend of Models in a period with slowly growing
forecast spread and uncertainty. 00 UTC guidance remains in line.
...Weather Highlights/Hazards...
Record-breaking and dangerous heat now over the
Southwest/California is expected to return to seasonal next week.
However, heat will intensify from the interior Northwest to the
north-central Great Basin/Rockies and Plains where some record
values may build.
In the wake of wet "Three", well organized convective rains and
lingering runoff issues are expected for the Gulf Coast states and
the Eastern Seaboard Tuesday with frontal passage. Some activity
will linger over the Southeast/Florida into later next week with
the stalling front. Digging upper energy, instability and frontal
support upstream may combine to favor an emerging late week strong
convection/rain threat for the Midwest.
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, 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