Area Forecast Discussion
Issued by NWS Des Moines, IA

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579
FXUS63 KDMX 161114
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
614 AM CDT Thu May 16 2024

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Scattered showers and isolated storms ending east this
  morning.

- Warmer Friday into Saturday with highs into the 80s.

- Active pattern Sunday afternoon into early next week. Threat
  for severe weather and heavy rainfall may develop Sunday night
  and again Monday night into Tuesday, although specific
  details remain uncertain at this time.

&&

.DISCUSSION...
Issued at 316 AM CDT Thu May 16 2024

Weak convection continues across portions of north central into
northeast Iowa early this morning ahead of a weak boundary passing
into the state.  Otherwise, some patchy fog has developed ahead of
the boundary in portions of southern Iowa and this is likely to
persist in advance of the front through daybreak.  Otherwise, the
front advances eastward across much of the forecast area by midday
with increasing subsidence and drier air overspreading much of the
area.  The exception may be the far southeast where some
redevelopment occurs prior to frontal passage but any activity would
quickly exit the area into eastern Iowa.  Cold advection is most
pronounced across northern Iowa today but good mixing and some
sunshine should keep temperatures similar in most areas to
Wednesday`s highs or perhaps slightly warmer in the south where
the cold advection is much more negligible.

An upper trof across western Canada into the northwest United States
has a shortwave passing through the base on Friday into Saturday
over the northern US Rockies.  Warm advection ahead of this system
is expected to intensify across Iowa tonight into Friday with
increasing southerly surface flow.  Temperatures should respond in
kind by Friday afternoon as highs climb into the 80s over much of
the area with ample insolation through the day. As the upper system
pushes through North Dakota and Minnesota, it sends a boundary
across Iowa on Saturday.  Instability develops ahead of this front
by afternoon with MUCAPES in vicinity of 1500-1800 J/KG however
soundings indicate a decent cap is in place for much of the day.
Sufficient mechanical forcing near the front may be enough for a few
isolated storms during peak heating but it appears to remain limited
at this point.

Beyond this point, broad west to southwest flow develops across much
of the United States heading into next week. Both the GFS and Euro
indicate strong return flow on Sunday with moisture surging back
north into the state with increasing chances of storms by the
afternoon in the west.  Chances overspread much of the state into
Sunday night as the low level jet veers over Iowa.  Additional
convection seems likely on Monday into Tuesday as a surface wave
develops along a boundary in Kansas and moves northeast toward Iowa.
The threat for heavy rainfall is expected during this time along
with some potential for severe weather.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 614 AM CDT Thu May 16 2024

Scattered MVFR ceilings and visibilities are common across
central Iowa this morning but conditions improve to widespread
VFR by late morning. The VFR conditions are then expected to
persist through the end of the forecast period. Surface winds
mainly from the west northwest today becoming light from the
south tonight.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

DISCUSSION...Cogil
AVIATION...Cogil