Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
423 PM EDT Wed Jul 31 2019
Valid 12Z Sat Aug 03 2019 - 12Z Wed Aug 07 2019
...Overview and Guidance/Predictability Assessment...
Strong upper ridging over southwest Alaska and the northeast
Pacific favors troughing along the Pacific Northwest and through
the Great Lakes with weakening ridging over the Four Corners
region. The model/ensembles mostly agree on the longwave pattern
and a blend of the deterministic models sufficed for the weekend
period. The 00z ECMWF became an outlier by trying to bring the
Northwest trough eastward and was deemed less useful with time
after Monday.
...Weather Highlights/Threats...
Monsoonal moisture will focus rainfall mostly over New Mexico
Saturday then into AZ/UT/CO next week. Leftover MCS (uncertain
details) may sink through Arkansas early Saturday as it rounds the
ridge. Elsewhere, rainfall will follow the front in the north and
largely pop up in the afternoon in the Southeast, perhaps enhanced
over eastern Florida into the coastal Carolinas as the tropical
wave/related disturbance and stationary front across the region
dissipate/weaken.
Temperatures will be a bit cooler than average over the central
states with higher chances of rainfall and clouds. Milder than
average temperatures are expected over the Great Lakes and
Northeast ahead of the northern tier system. Elsewhere,
temperatures will be within a few degrees of typical early August
values during the day and near/above average for overnight mins in
much of the West.
Roth/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
Hazards:
- Heavy rain across portions of the Middle/Lower Mississippi
Valley and the Southern Plains, Sat-Sun, Aug 3-Aug 4.
- Flooding possible across portions of the Upper Mississippi
Valley and the Northern Plains.
- Flooding occurring or imminent across portions of the Lower
Mississippi Valley and the Northern Plains.
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