Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Des Moines Iowa
705 PM CDT Tuesday Jul 22 2014

Short term /tonight/...
issued at 320 PM CDT Tuesday Jul 22 2014

Frontal boundary passing through central Iowa this afternoon with
only isolated convection so far. Will likely see some better
coverage across the far south early this evening before the boundary
shifts into Missouri. Certainly sufficient cape for intense
updrafts although wind shear somewhat marginal. At this Point...
May see a few severe storms in the far southeast prior to departure
from the state with large hail and damaging winds the main threat.
Otherwise...will still see a few hours of heat indices in the lower
100s along and south of Kalo-kamw-kadu line and have continued the
advisory in these areas. Otherwise...north winds will transport a
much more comfortable Canadian airmass into the state overnight with
temperatures much closer to normal by morning.

Long term /Wednesday through Tuesday/...
issued at 320 PM CDT Tuesday Jul 22 2014

High pressure will begin to push into the upper plains Wednesday
with cooler and drier conditions through the day. However as high
pushes south winds will again shift to the south with increasing
moisture through the night Wednesday night. Ridge to the west of
state will begin to break down as large upper level low pressure
system tracks east across southern Canada. Models remain
consistent with wave pushing through ridge to the west of Iowa
Thursday. However...timing has not been consistent. Current model
trends indicate best chance across the west in the morning hours
Thursday...before decreasing somewhat into the afternoon as wave
weakens and lifts north...though still feel enough moisture and
forcing will be present to allow for slight chance probability of precipitation through
the day. Better forcing arrives overnight and into Friday. Models
keep best dynamics west of County Warning Area in the afternoon hours
Thursday...though enough cape/shear across northern Iowa to allow
for thunderstorm potential...and storms may be severe in west and
north...though will need to be monitored.

System will push quickly eastward and large upper level low will
drop south...generally into the northern plains. Models have poor
agreement on timing of this however. This will allow for cooler
temperatures to prevail...though periods of showers and
thunderstorms will be possible generally late Saturday into Sunday
near low as it begins to pull eastward. For end of
extended...models indicate amplified ridge building into
rockies...with northwesterly flow aloft across Iowa. This will
lead to additional periods of cooler temperatures and generally
dry conditions.


issued at 705 PM CDT Tuesday Jul 22 2014

VFR conditions are expected through the period with mostly clear
skies and light generally north winds. No precipitation or obscurations
are anticipated.


Dmx watches/warnings/advisories...none.



Short term...cogil
long term...awb

National Weather Service Glossary of Abbreviations