Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 162329
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
529 PM CST Thu Feb 16 2017

.SHORT TERM.../Tonight through Friday/
Issued at 341 PM CST Thu Feb 16 2017

An upper ridge builds into the state tonight through Friday and
strong warm advection sets up.  Winds aloft are quite brisk but due
to the strong inversion that sets up we will have little mixing and
surface winds through Friday will not be very strong.  10-15kts is
all we are forecasting at this point.  With dry conditions and
little to no snow left in the state we should see temps warm to
record or near record highs for all but the far Northeast and even
they will see highs in the mid to upper 50`s.

By late in the day Friday, a weak surface low develops over the
Plains and drifts across Southern MN dragging a weak cold front
through the state.  This will lead to only slight cooler temps on
Saturday which will be discussed below.  The front will enter the
far Northwest between 21Z and 00Z Friday.  The severe lack of
moisture will preclude any sensible weather other than a wind shift
to the West/Northwest and maybe some high clouds.

.LONG TERM.../Friday night through Thursday/
Issued at 341 PM CST Thu Feb 16 2017

Large scale flow through the weekend will be dominated by large
upper ridge across the central United States. Despite a weak front
passing through the state Friday night, the bulk of cold advection
with the system will remain well north of Iowa. The mild airmass
from Friday will linger into the weekend although slightly
modified by the boundary pushing through on Friday night.
Therefore, readings well above normal will persist through Sunday
with overnight lows even several degrees above the normal daytime
highs.

A significant shortwave will pass through the southwest US this
weekend with a tendency over time of the north stream energy
remaining more progressive and shearing away from the lagging
southern low, which will lag over Texas by Monday night. Moisture
will stream northward ahead of this system Sunday night with
isentropic lift increasing through Iowa on Monday. In addition,
weak elevated instability will also work into the state during the
day. Scattered shower activity is expected during the day with
some thunder by afternoon across much of the area in the narrow
instability axis. The forcing ends abruptly on Monday evening with
precipitation ending by late evening.

Thereafter, upper ridging will continue to dominate the central
United States for much of the work week. This will allow the
abnormally warm weather to persist for much of the week. The
onslaught of western system will eventually begin to break down
the mid continent ridging with a strong system entering the region
toward the end of the period. Still much divergence in model runs
on location of system in relation to Iowa, but precipitation
chances will surely increase by later Thursday and Friday as the
system nears the state.

&&

.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 528 PM CST Thu Feb 16 2017

There is high confidence in VFR conditions through the period with
a dry airmass and nothing beyond patchy high cloudiness. Winds
will gradually become more southerly and increase somewhat into
Fri afternoon.

&&

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

&&

$$

SHORT TERM...FAB
LONG TERM...Cogil
AVIATION...Small


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