Area Forecast Discussion
Issued by NWS Des Moines, IA

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183
FXUS63 KDMX 190440
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1140 PM CDT Sun Jun 18 2017

.SHORT TERM.../Tonight through Monday/
Issued at 332 PM CDT Sun Jun 18 2017

CU field in place with back side of upper trough/cyclonic flow
remains aloft across the area today into Monday. Seeing some
enhanced CU on satellite and a few echoes on radar across far north
central IA and southern MN. This trend should continue with pop-up
showers/possible weak thunderstorms through the remainder of the
afternoon into early evening with steep lapse rates aloft and weak
instability. Could have a few gusty winds or small hailstones with
any stronger storm that might develop this afternoon, given the low
freezing levels. Another weak shortwave to dig into the back side of
the upper trough Monday which could help bring some showers/storms
again to the northern/eastern half of the area by late morning into
the afternoon hours. Again with the low freezing level on Monday and
slightly stronger instability, could see some low to possibly even
marginally severe hail with any stronger storm Monday afternoon.

Temperatures should cool off pretty decent tonight with mostly clear
skies across much of the area through the night and drier air in
place. Temperatures to be slightly warmer into Monday with low level
waa and moisture advection across much of the state. Therefore have
temps topping out in the mid to upper 70s and low 80s.

.LONG TERM.../Monday night through Sunday/
Issued at 332 PM CDT Sun Jun 18 2017

A relatively active pattern through the extended. The diurnal
showers/storms from Monday should be diminishing quickly by the
evening. The next short wave/PV anomaly will be dropping quickly
through the northwest flow after midnight Monday night. This will
bring another round of showers and a few storms to mainly
northwest Iowa. High pressure will arrive and bring a pleasant day
for Tuesday with an abundance of sunshine, a light breeze and dry
conditions.

Strong return flow will develop Tuesday night as the high pressure
departs to the east and low pressure moves into the Dakotas and
Nebraska. The return flow likely will help spark a few elevated
thunderstorms as the forcing passes across the state into
Wednesday morning. Drier and much warmer conditions should arrive
by the afternoon as the elevated mixed layer (EML) becomes
established. The next weak impulse will reach the area Wednesday
evenings as a surface boundary enters the nw portion of the state.
This set up with good instability ahead of the boundary will have
the potential for severe weather. The boundary will linger over
central Iowa on Thursday and should lead to another round of
storms during the late afternoon and night ahead a stronger
shortwave.

By the end of the week, much of the Upper Midwest will be within
the trough of a large upper low over Hudson Bay. Another strong
shortwave moving through this flow should arrive by next weekend
bringing another chance for showers and storms. In addition,
cooler conditions can be expected as the boundary passes through
Thursday night and the evolution into the upper low trough occurs.

&&

.AVIATION.../For the 06Z TAFS through 06Z Monday night/
Issued at 1140 PM CDT Sun Jun 18 2017

VFR conditions will remain widespread for the duration of the
forecast with any ceilings generally at or above 8kft. Surface
winds will be light overnight but increase once more from the west
northwest on Monday as daytime mixing increases. A few showers
will once again be possible in northeast portions of the state and
may affect KMCW and KALO during the afternoon with main concern
from restrictions to visibilities.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Beerends
LONG TERM...Donavon
AVIATION...Cogil



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