Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
241 AM EDT Wed Jul 04 2018
Valid 12Z Sat Jul 07 2018 - 12Z Wed Jul 11 2018
...Overview...
An upper high will continue to dominate the lower 48 this coming
weekend into the middle of next week. Troughs in the Northwest and
Northeast will flatten with time as a more zonal flow takes shape
along the US/Canadian border as heights become above average from
coast to coast. A front in the east will sink into the Southeast
this weekend and dissipate next week as a western front tilts
across the Upper Midwest/Great Lakes and eventually moves into the
Northeast.
...Weather threats/highlights...
Temperatures will be near or below average in much of the east
this weekend but trend back to above average by the middle of next
week. The Deep South will lie south of the upper high and subject
to easterly mid-level shortwaves that, coupled with the surface
front, will maintain a daily chance of showers/storms and cooler
than average max temperatures. The west will see near to above
average temperatures, especially Saturday in southern California
with 90s likely to the coast and 100s inland which should
tie/break daily records.
Moisture is forecast to gradually increase into the Southwest out
of Mexico, first into New Mexico and then into Arizona. This will
keep daytime temperatures near or a couple degrees below average.
...Guidance evaluation/preferences...
Models/ensembles remained in very good agreement and a consensus
blend was used through the period. The 12Z ECMWF may be too
aggressive in its forecast of a forming upper low in the Northeast
next Wednesday as the consensus lied offshore in a weaker state.
Fracasso
WPC medium range forecasts of 500 mb heights, surface systems,
weather grids, quantitative precipitation, and winter weather
outlook probabilities 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