Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1156 AM EDT Thu Jul 05 2018
Valid 12Z Sun Jul 08 2018 - 12Z Thu Jul 12 2018
...Weather threats/highlights and Guidance
evaluation/preferences...
It remains the case that an upper high will dominate much of the
lower 48 next week. Troughs over the Northwest and Northeast
overall flatten with time as a more zonal flow takes shape along
the US/Canadian border. Heights will become above average coast to
coast which supports near to above average temperatures over most
areas outside the southern tier. A moderating front in the east
will dissipate next week as western North American fronts shift
downstream across the northern plains, Upper Midwest/Great Lakes
and Northeast along with thunderstorm focus and local severe storm
threat as per SPC. The Southwest will see enhanced monsoonal
moisture around the upper high realized as precipitation initially
over the higher terrain and then into some of the lower deserts.
The WPC medium range product suite was mainly derived from a blend
of reasonably clustered guidance from the 00 UTC GFS/ECMWF and
NAEFS/ECMWF ensembles into Day 5/Tue. Quickly switched to
ensembles only later Tuesday to days 6/7 given increasing model
forecast spread/smaller scale system uncertainty. The 06 UTC
GFS/GEFS trended toward progression, but this scenario seems less
likely considering upstream northern Pacific to Alaskan flow
amplification.
Schichtel
WPC medium range 500 mb heights, surface systems, weather grids,
quantitative precipitation, winter weather outlook probabilities
and heat indexes are found at:
http://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
http://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
http://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
http://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
http://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
http://www.wpc.ncep.noaa.gov/heat_index.shtml