Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
245 AM EDT Sun May 19 2019
Valid 12Z Wed May 22 2019 - 12Z Sun May 26 2019
...Overall Weather Pattern...
The upper level pattern across the continental U.S. will remain
quite amplified and slow to change next week. A hot upper level
ridge over the southeast U.S. becomes anchored over the region and
gradually becomes stronger for the second half of the upcoming
work week. Across the western U.S., a large scale upper trough
will be dominant as multiple shortwave perturbations keep
conditions cool and unsettled. This will also be slow to move
given the expected development of an omega block type pattern
upstream over the eastern Pacific. Lead main weather features
include a strong low pressure system for the Plains and Upper
Midwest Tue/Wed, followed by weaker lows and frontal boundary
meanderings from the Southwest to the Northeast U.S. later week
overtop the Southeast ridge. The pattern offers a periodic local
threat for strong to severe convection and potential for cell
training/excessive rainfall.
...Weather Highlights and Hazards...
The main things that will make weather headlines for the second
half of the week and extending into next weekend will be the
anomalous heat and humidity building across the southeastern
quadrant of the nation, the unseasonably cool weather expected for
the interior western U.S. and northern plains, and the ongoing
threat of heavy rainfall and potential severe weather across the
central U.S. High temperatures are forecast to be on the order of
10 to 15 degrees above late May averages from the Midwest to the
Southeast U.S., with the hottest readings expected for the Friday
to Sunday time period. There is a good chance that the first 100
degree temperatures of the season could be realized across inland
portions of southern Georgia and South Carolina. The opposite
will hold true for the western U.S. under the influence of the
upper level trough, with daytime highs of 15 to 25 degrees below
normal for mid-week, and then moderating to 5 to 15 degrees below
normal by the end of the forecast period.
D. Hamrick
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