Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
226 AM EDT Sat Jul 27 2019
Valid 12Z Tue Jul 30 2019 - 12Z Sat Aug 03 2019
...Overview and Guidance/Predictability Assessment...
An upper high will meander around the Four Corners region as
troughing digs into the eastern states as well as the Pacific
Northwest. The models/ensembles largely agree for the first few
days of the period (Tue into Thu) and a general model blend
sufficed. For later next week into next Saturday, 18Z GFS and 12Z
ECMWF showed reasonable agreement though displaced a bit from the
ensemble means in the northeast Pacific where the guidance has had
trouble settling on a solution. Trend seems to be for a bit slower
progression which favors the GFS/ECMWF more than the slightly
quicker ensemble means, so shifted the forecast in that direction
but with limited confidence. Downstream result may be for a bit
deeper troughing and a farther southward push of a cold front into
the TN Valley.
...Weather Highlights/Threats...
Temperatures in the Southwest will trend cooler as monsoonal
moisture increases and clouds/showers/storms expand in coverage.
Convective rainfall including some locally heavier
downpours/runoff issues will focus along and ahead of the frontal
boundaries from the Great Lakes to the Northeast and southward to
the southern Plains/lower MS Valley/Southeast. Florida may see an
enhanced period of rainfall with a dissipating surface boundary
over the central peninsula early next week. The Pacific Northwest
will see an increased chance of rain with an approaching system
later in the week.
Fracasso
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