859
FXUS02 KWBC 112005
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
405 PM EDT Mon May 11 2026

Valid 12Z Thu May 14 2026 - 12Z Mon May 18 2026


...Guidance/Predictability Assessment...

Guidance seems reasonably clustered with the overall larger scale
upper pattern evolution through next Monday, as highlighted by a
warming ridge that slides eastward into the central U.S. as an
amplified downstream trough shifts over/off the Northeast.
Notably, guidance has trended slightly more amplified for this
trough over New England, with higher warp-around QPFs into interior
New England Friday to Saturday.

Across the Northwest, with the upper trough pushing through and
then interacting with northern stream this weekend, there is higher
uncertainty on how the surface low will consolidate over the
northern Plains. Ensemble means are reasonably agreeable among
models but there is emerging agreement for an elongated low to
consolidate over the central Plains on Sunday. The latest guidance
is placing a little more emphasis on a wave ejecting out the
central Rockies toward the Midwest on Friday. In addition, guidance
has shown a trend for a stronger cyclone to move faster across
southern Canada. This stronger cyclone has resulted in a better-
defined front to trail south and interact with the ejecting wave
over the central Plains. The end result is an increase in rain
chances from the Midwest toward Ohio Valley Friday to early
Saturday ahead of a warm front lifting northeastward from the
central Plains.

There is also a trend for the aforementioned elongated low to be
deeper over the central Plains by Sunday. This will tend to
enhance southerly flow up the Plains toward the Midwest as the
weekend progresses. The associated dynamic forcings will likely
lead to higher temperatures across central to southern Plains this
weekend, as well as higher precipitation and thunderstorm chances
across the upper Midwest Sunday into Monday associated with a warm
front.

With the uncertainties noted above, the WPC forecast charts
are based on the latest global model consensus but with higher
percentages from the ensemble means beginning on Day 5 Saturday.


...Weather/Hazards Highlights...

It generally remains the case that an eastern Canadian closed
upper-level low/trough will help support longwave troughing down
over the eastern U.S. through late week. Impulses will lead to the
progression of a wavy frontal systems and showers/thunderstorms
through the East. System progression to the Atlantic will spawn
moderate coastal cyclogenesis with wrapping moisture/rains lifting
up/off the East Coast as a maritime threat. Troughing breaks down
by the weekend as low amplitude ridging builds in from the west.

Upstream, an eastern Pacific closed low is slated, still with much
uncertainty, to advance inland mid-late week to focus organized
light to moderate precipitation most likely across portions of the
northern Great Basin, Pacific Northwest, and northern Rockies.
Surface lows and frontal boundaries will form downstream, bringing
weekend shower/thunderstorm chances broadly from the central U.S.
to the Midwest/Great Lakes/East. Farther upstream system energies
with some showers will subsequently work inland into the West and
downstream over the lower 48 with uncertain timing in embedded
shortwaves and occasional amplifictions within a generally zonal
pattern aloft.

Temperatures for the eastern U.S. will be below normal into late
week before moderating with upper trough ejection to the Atlantic.
Meanwhile, an eastward shifting upper ridge will gradually spread
well above normal temperatures across the Central to East-Central
U.S. that may produce several summertime high temperature records.


Kong/Schichtel


Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw








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