Area Forecast Discussion
Issued by NWS Des Moines, IA

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
000
FXUS63 KDMX 062107
AFDDMX

AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
307 PM CST Tue Dec 6 2016

.SHORT TERM.../Tonight through Wednesday/
Issued at 307 PM CST Tue Dec 6 2016

A strong cold front that move through central Iowa early this
morning has now pushed east of the Mississippi River and has left
colder and much drier air in its wake. Deep low pressure over far
northwest Minnesota has brought broad cyclonic flow to Iowa. A few
patches of flurries have reached as far south as the IA/MN border
this afternoon. The increasing temperatures and dewpoint spreads
in northern Iowa are likely resulting in any flurries there
evaporating before reaching the surface. A vigorous short wave
will be moving east across Kansas and Missouri overnight with QG
forcing spreading north into far southern Iowa. Moderate forcing
and increasing moisture above 700 mb is expected over far southern
Iowa after 06z. Have kept the forecast dry at this time with the
dry air below 700 mb expected to prevail. Light snow could occur
though is forcing is stronger aloft than anticipate which could
force saturation deeper into the dry air and limit the
evaporation impact.

Gusty winds will continue the next few hours before diminishing a
bit towards sunset. That said another wave of cold advection will
arrive tonight and will keep mixing intact keeping conditions
breezy. The mixed conditions will also keep temperatures from
dropping significantly overnight with overnight lows in the low
teens northwest to low 20s southeast. Wednesday will again be
breezy and cool. Shallow cumulus development may occur though deep
layer subsidence will be in place with a weak high pressure ridge
over the state. High temperatures will be in the upper teens to
upper 20s.

.LONG TERM.../Wednesday night through Tuesday/
Issued at 307 PM CST Tue Dec 6 2016

Another wave of cold advection will arrive late Wednesday into
Wednesday night. Expect the stratus plume to the north to wrap
southeast into at least the northeast half of the forecast
area into Thursday. Expect areas of flurries to possible very
light snow to accompany the stratus. Much of the lower 10 kft of
profiles will be situated within the -10 to -20 C dendritic range
resulting in the light precipitation potential. High temperatures
Thursday will be in the mid teens to low 20s. These temperatures
combined with northwest wind of 20 to 30 mph will bring wind chill
values in the zero to 10 below range Thursday morning and rising
slightly in the afternoon. High pressure ridge will move across
the state Thursday night and Friday and will bring less wind but
also will allow temperatures to drop into the single digits to
low teens by Friday morning.

Warm advection aloft will begin to spread east across Iowa as the
ridge moves east and low pressure intensify to the west over
eastern Colorado. The warm advection will bring the potential for
light snow over northern Iowa Friday night into Saturday. The
chance for snow will drop further south late Saturday into
Saturday night as gulf moisture streams north and enters into the
state. Uncertainty on how much the northern and southern stream
systems phase but this event could result in several inches of
snow across portions of Iowa should the southern moisture be
ingested into the northern system. The beginning of next week will
feature an upper low digging into Manitoba and Alberta. This will
allow arctic air to plunge south into Tuesday with 850 mb
temperatures near -20C nearing northern Iowa. The boundary likely
would have attendant light snow.

&&

.AVIATION.../For the 18Z TAFS through 18Z Wednesday afternoon/
Issued at 1138 AM CST Tue Dec 6 2016

VFR conditions will prevail most sites through the period. KMCW
will have intermittent MVFR cigs this afternoon that may linger in
to this evening. Breezy west wind will continue this afternoon
with the gusts diminishing overnight before increasing again
Wednesday morning. Mid level clouds will increase overnight but
remain AOA 10 kft.


&&

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

&&

$$

SHORT TERM...Donavon
LONG TERM...Donavon
AVIATION...Donavon



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.