Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
332 PM EDT Thu Jul 25 2019
Valid 12Z Sun Jul 28 2019 - 12Z Thu Aug 01 2019
...Weather Highlights/Threats and Guidance/Predictability
Assessment...
A strong/hot upper high will slowly migrate out of the Southwest
and into the southern Rockies next week as a summertime upper
ridge builds through the west-central U.S. The Southwest will see
an increase in monsoonal-driven showers/storms as the upper high
moves to the east of Arizona, allowing Mexican moisture to advect
northward and around the upper high across the south-central Great
Basin/Rockies. This main ridge/high will be sandwiched by
gradually amplifying upper troughs offshore the Northwest and over
the eastern U.S. A lead and weakening surface front stalled over
Florida and the Gulf of Mexico will boost convective potential
into early next week. Surface fronts will also meanwhile traverse
the US/Canadian border through this forecast period with area-wide
light/modest rainfall, but with a risk of locally heavier amounts
with focused convection, especially over and downstream from the
Midwest/Great Lakes. Model and ensembles agree fairly well with
each other Sun-Tue such that a consensus blend approach served
well as a starting point. By next Wed/Thu the 00/06 UTC GFS offer
a break from continuity and now bring much more ample Pacific
height falls/troughing rapidly inland across Canada. This is not
well supported by GEFS/ECMWF ensembles that preferably hold more
system energy offshore more in line with the 00 UTC ECMWF and WPC
continuity.
Schichtel
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
Hazards:
- Heavy rain across portions of the Upper Midwest and the Upper
Great Lakes, Sun, Jul 28.
- Flooding occurring or imminent across portions of the
Mississippi and Missouri River Basins.
- Excessive heat across portions of California, Sun, Jul 28.
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