Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 181729

National Weather Service Des Moines IA
1229 PM CDT Tue Oct 18 2016

.SHORT TERM.../Today/
Issued at 336 AM CDT Tue Oct 18 2016

Cold front currently progressing across the state as shortwave
passes through the upper Midwest.  Have seen a narrow band of low
clouds where moisture has condensed in the frontal inversion
immediately behind the boundary.  However, as drier air advects in
from the north and deepens, the low cloudiness has dissipated.
Expect much of the low clouds to be out of the forecast area an hour
or two after sunrise.  May continue to see some mid level cloudiness
in the far north for a while this morning, but even those clouds
will dissipate as the system pulls away from the state this
afternoon.  Otherwise, cold advection will continue today as thermal
trof builds toward state.  Highs will be a good 15 degrees cooler
than yesterday but still above normal for this time of the year -
Just goes to show how warm temperatures were on Monday.

.LONG TERM.../Tonight through Monday/
Issued at 336 AM CDT Tue Oct 18 2016

Summary...Temperatures cool through Thursday, though still within a
few degrees of normal, then rise back above normal through the
weekend and into next week. Only real opportunity for
precipitation through early next week to move through Wednesday

Tonight through Wednesday Night...After record highs through parts
of the state Monday, temperatures will continue to moderate back
towards normal during this time frame as northerly winds and high
pressure moves in and dissipates ahead of amplifying trough. Best
opportunity for precipitation chances through forecast Wed night,
though questions remain. Best overall lift will reside SE of area
within the right entrance region of upper jet and vicinity of
surface front. Over Iowa, a series of vort maxes will round the base
of the trough as it amplifies and pivots through, providing a fair
amount of lift. Cloud cover of no question, however precipitation
anything but a slam dunk with fair amount of low level dry air to
overcome. Expectation is that pockets of light rain will develop
within areas of greatest lift/vorticity, and not much more with nil

Thursday through Monday...Trough will finish pivoting through the
region, introducing northerly flow through Thursday and dropping
temps on the cool side of normal in the 50s. While northwest upper
flow will dominate the remainder of the period both Euro/GFS build in
periods of 850mb ridging into Mon, allowing temperatures to slowly
rise back above normal into the 60s and possibly touching 70.
Euro/GFS also diverge a bit within this window, though both keep
precipitation chances away until early/mid next week as they begin
to significantly diverge.


.AVIATION.../For the 18Z TAFS through 18Z Wednesday afternoon/
Issued at 1229 PM CDT Tue Oct 18 2016

There is a high confidence in VFR conditions through the period. Skies
were clear over nearly the entire forecast area at 17z and
outside of some patchy mid clouds brushing western sections
through early this evening conditions should remain that way. NW
winds will diminish becoming either variable or light NE into Wed





LONG TERM...Curtis
AVIATION...Small is the U.S. government's official web portal to all federal, state and local government web resources and services.