Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1156 AM EDT Wed Jun 19 2019
Valid 12Z Sat Jun 22 2019 - 12Z Wed Jun 26 2019
...Weather Highlights/Threats...
Deep layer southerly flow under an upper ridge over the central
CONUS continues to advect warm air east across the southern
Mississippi Valley and the Southeast/TN Valley/Oh
Valley/Appalachians over the weekend, and continuing into the
Northeast early next week. Expect high warm sector temperatures
under this ridge including a risk of record warm minimum values
mainly for the eastern southern Plains and lower MS Valley
Saturday.
Forcing ahead of the trough crossing the Rockies this weekend
presents a threat of strong to severe/MCS convection and locally
heavy rains in areas with pooling moisture/instability. The
rainfall focus Sunday and Monday is forecast to be from eastern
Kansas and Oklahoma across the Mississippi Valley into the Great
Lakes and the Midwest.
On Tuesday/Wednesday the showers/storms are expected to focus from
east Texas across the Arklatex to the lower MS Valley, Ohio and TN
Valleys and the Northeast.
...Guidance/Predictability Assessment...
The WPC medium range product suite was derived from a composite
blend of compatible guidance from the 06 UTC GEFS and 00 UTC
ECMWF/UKMET and 00 UTC ECMWF ensemble mean guidance. The 06 UTC
deterministic GFS continued a trend of strengthening a shortwave
rounding a trough over the western CONUS and closing off as a
mid-level low over the Desert Southwest by Saturday which is not
in agreement with the preferred consensus.
The preferred models agree on the large scale pattern of the
initial northern Rockies closed low moving north into Canada by
early next week and a high amplitude southeast ridge persisting.
Next week, a new closed low develops and moves southeast from
offshore British Columbia into the Pacific northwest or adjacent
coastal waters by the middle of next week. This persistent and
slow moving circulation allows the deep layer ridge to rebuild
over TX and NM. There is less spread than normal for this
consensus, lending the situation to a consensus based approach.
Jackson
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 Central and Southern Plains,
the Mid and Upper Mississippi Valley, the Great Lakes, and into
the Ohio Valley, Sat-Sun, Jun 22-Jun 23.
- Heavy rain across portions of the Lower Mississippi Valley and
the Southern Plains, Mon-Tue, Jun 24-Jun 25.
- Flooding possible across portions of the Central and Southern
Plains, the Middle Mississippi Valley, and the Ohio Valley.
- Flooding occurring or imminent across portions of the Central
Plains, the Lower and Middle Mississippi Valley, the Ohio Valley,
and the Tennessee Valley.
- Flooding likely across portions of the Central Great Basin and
the Ohio Valley.
- Excessive heat across portions of southern Texas, Sat-Mon,
Jun 22-Jun 24.
- Much below normal temperatures across portions of the High
Plains, the northern and central Rockies, and into much of the
Great Basin, Sat-Sun, Jun 22-Jun 23.
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