Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
307 AM EDT Sat Jul 13 2019
Valid 12Z Tue Jul 16 2019 - 12Z Sat Jul 20 2019
...Tropical Storm Barry expected to weaken as it tracks up the
Mississippi Valley/Lower Ohio Valley but continue to produce areas
of heavy rainfall...
...Overview and Guidance/Predictability Assessment...
...Weather Highlights/Threats...
The forecast track for Tropical Storm Barry, per the National
Hurricane Center, has it making landfall in south-central
Louisiana on Saturday July 13. Once inland, Barry will weaken as
it goes north through Arkansas and then curve eastward through
Missouri and Illinois as a remnant low by the beginning of the
extended period (Tuesday). Heavy rain associated with this system
will spread from central Arkansas to southern Indiana by Wednesday
morning. There may be a severe threat over some areas to the right
of the surface low track but with low predictability in details
this far out in time. Later in the week the remnants of Barry
could interact with a wavy northern stream front and produce
enhanced rainfall over the Northeast, but this depends on the
strength of Barry in the short term and timing in the northern
stream in several days. Please consult latest NHC products for
updated information on Barry.
Much of the Southwest, Southern/Central Rockies and High Plains
will remain mostly dry as mid/upper level ridging remains in
place. Southern Canada and the northern states will have organized
convection bringing up to 1 to 2 inches through Thursday, and
across the Northeast Thursday and Friday, within the low amplitude
flow. Periods of excessive rainfall may be possible across the
Northern Plains and Upper Mississippi Valley/Upper Great Lakes as
a frontal boundary stalls over the region. The pattern across the
West will transition as a low approaching the Pacific Northwest
toward the end of the week. This would bring a period of steadier,
light to locally terrain-enhanced moderate rainfall between the
Pacific Northwest coast and Cascades. Consult the latest WPC
Hazards chart for more information on these potential threat.
A few locations will have above normal temperatures that may tie
or set new daily high minimum records. Above normal temperatures
with some pockets of plus 10F or greater anomalies will spread
from the Northern Plains into Northeast through Wednesday with
some warmth lingering over the Northeast into Friday. The
increased cloudiness from Tropical Storm Barry will likely keep
the afternoon temperatures slightly cooler over portions of the
Lower Mississippi Valley (perhaps near record low max values).
Once Barry passes, portions of the Central Plains and
Mid-Mississippi Valley will reach 10 to 15F above average by the
end of the forecast period. Heat indices will be around 105 to
115F with parts of the Southern Rockies and Southern High Plains
5 to 10 F warmer. The Pacific Northwest will trend cooler by
Friday with highs 5 to 10F cooler than average.
This forecast was mostly based off of the 00Z ECWMF, with lighter
weighting of the GFS, CMC and ECWMF mean.
Campbell
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