Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
207 AM EDT Tue Jul 07 2020
Valid 12Z Fri Jul 10 2020 - 12Z Tue Jul 14 2020
The WPC product suite was mainly derived from a composite of
reasonably clustered guidance from the 18 UTC GFS/GEFS mean, 12
UTC ECMWF/ECMWF ensemble mean and 01 UTC National Blend of Models.
This blend maintains good WPC continuity and seems supported by
newer 00 UTC model guidance. Smaller scale differences remain with
an Eastern Seaboard coastal low currently being monitored by NHC.
The WPC composite offers moderate development versus deeper recent
UKMET runs, whose solutions fall within ensemble forecast spread
and seem to benefit from a more offshore track east of the main
upper trough and over warmed water.
...Weather Pattern/Hazard Highlights...
Upper trough energies will periodically work inland over an
unsettled Northwestern U.S. and western Canada. A steady stream of
ejecting impulses then progress downstream over southern Canada
and the U.S. northern tier. This will force moderating fronts over
the broad region and spawn some strong to severe thunderstorms.
Convective rainfall potential may focus from the Midwest to the
Northeast and with a stalled/wavy front over the humid
South/Southeast. Triple digits maximum temperatures
(approaching/exceeding some heat records) are likely from portions
of CA and the Southwest/southern Great Basin to the south-central
Plains, with heat indices making it feel closer to 115 in some
places. A heavy rain/weather threat is also expected to lift from
the coastal Mid-Atlantic to New England contingent on potential
coastal low development and track.
Additional 3-7 Day Hazards information can be found on the WPC
medium range hazards chart at:
WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, winter weather outlook probabilities
and heat indices are at: