Area Forecast Discussion
Issued by NWS Des Moines, IA

Current Version | Previous Version | Text Only | 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 44 45 46 47 48 49 50
000
FXUS63 KDMX 240857
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
357 AM CDT Fri Mar 24 2017

.SHORT TERM.../Today through Tonight/
Issued at 356 AM CDT Fri Mar 24 2017

Intense low pressure system over southeast Colorado this morning
with a very pronounced warm front extending northeast into southeast
Nebraska and southwest Iowa. Temperatures at 3 am this morning were
still in the low to mid 60s over southwest Iowa while temperatures
were in the upper 30s across the far northern portion of the state.
Showers and a few thunderstorms were currently confined to the
northwest third of the state and northwest of a Harlan to Fort Dodge
and Mason City line. The precipitation will remain prevalent over
this area the next few hours. The latest CAMs push the precipitation
mostly north of the IA/MN border by 12z which looks reasonable and
have begun to diminish pops as a result for early today.

The area of low pressure will begin to shift slowly east today and
fill. A strong area of theta-e advection will lift northeast this
morning through Missouri and into Iowa. This will be the catalyst
for increasing instability and the potential for showers and
thunderstorms across the forecast area. The potential for severe
weather should remain low today into tonight. The threat for strong
winds that were occurring overnight to the west will diminish as the
winds at 850 mb and below have diminished. As the low pressure moves
further east, it will drag the colder air south along with
increasing precipitation along the deformation axis through tonight
and will keep the potential for precipitation going for much of the
night.

A wide range in high temperatures today due to the boundary with 60s
and low 70s central and south and mid 40s far north. Lows tonight
will be mid 30s north to low to mid 50s far southeast.

.LONG TERM.../Saturday through Thursday/
Issued at 356 AM CDT Fri Mar 24 2017

Rainfall will continue on Saturday a stacked and slow moving low
gradually moves East.  PWAT`s continue to be around an inch through
the day.  The instability will have moved off to the East so not
really looking at much of a thunder potential, just a dreary wet
day.  Depending on how much rain we get today, rivers may need some
attention as well.  Still anticipating pretty decent within bank
rises and some minor flooding along the Cedar but confidence is not
high enough to do anything but monitor the situation at this point.

The low will move off into the Great Lakes for Sunday and bring an
end to precip over Iowa.  Temps will also be colder than what the
guidance is suggesting.  It`s gonna be hard to warm much with clouds
and precip all day Saturday and a warm front that will sag South
allowing for at least weak cold advection over all but the far
South.

Sunday night and Monday a strong wave will move across the Southern
into the Central Plains. Models vary on the location and strength of
this wave...with the GFS even developing a closed low with the
system...although right now that is the outlier solution. There will
be new precip chances with this system mainly across Southern Iowa
but if the GFS is right then precip will be a little more
widespread.

Late Monday night through Tuesday evening we will have an upper
ridge move overhead which will give us a dry and slightly warmer
period.

Wednesday through Thursday and beyond the forecast period another
closed low will move across the Southern/central Plains...very
similar to what we will see through Saturday...except that right now
models do have this low a little further South which means not quite
as much precip and it should mainly be across Southern Iowa.  Being
that this is in day 7 and models will change many times yet, not
much confidence in any one solution but it definitely bears watching
as there will again be heavy rain possible somewhere.

&&

.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 649 PM CDT Thu Mar 23 2017

Front will set up just north of the border overnight with a band
of showers across northern Iowa tonight in vicinity of the front.
Strong low level non convective wind shear is also likely
overnight with strong low level jet across the state. Ceilings
will mainly be VFR overnight but as front sags southward across
the state on Friday, ceilings will become MVFR to IFR in northern
to central Iowa during the day. There will also be widespread
shower activity during the day as well.

&&

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

$$

SHORT TERM...Donavon
LONG TERM...FAB
AVIATION...Cogil


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