Scientific Forecaster Discussion
fxus63 kdmx 150459
Area forecast discussion
National Weather Service Des Moines Iowa
1159 PM CDT Sat Sep 14 2019
Discussion.../tonight through Saturday/
issued at 339 PM CDT Sat Sep 14 2019
Convection that started out over eastern Nebraska and western Iowa
in an area of warm advection aided by a low level jet that has not
died. Storms have been very pulsy dropping brief heavy rainfall and
anywhere from pea to quarter sized hail. Storms will continue to
push through the state this afternoon and possibly early evening.
There may be a brief period this evening that is convection free but
a shortwave will pass through the northern plains tonight and brush
northern and possibly central Iowa Iowa. This will be coupled with
a surface low and trough traversing the state overnight. Forcing is
best over northeast into east central Iowa so the better/stronger
storms are expected. Shear is weak but the storms will have the
potential for some severe hail and wind. Bigger threat will be
heavy rainfall with pwat's increasing to 1.7 inches.
Precip threat pushes east by Sunday morning with ridging building
in. Return flow will push temperatures back into the mid 80s with
increasing dewpoints to around 70. By Monday/Tuesday highs will be
near 90 so well above normal for this time of year.
By Wednesday, a strong system carves a trough over the northern
plains into the upper Midwest bringing another chance for storms to
the region. Ridging builds back into the area for Thursday then
another shortwave rides the ridge late Friday/Saturday for
additional storm chances.
Aviation.../for the 06z tafs through 06z Sunday night/
issued at 1155 PM CDT Sat Sep 14 2019
Scattered thunderstorms possible overnight at most sites overnight
that will progress from north to south and are expected to be done
by 12z. The wind will become light and variable and there will be
some potential for fog especially across northern Iowa. VFR
conditions are expected much of the day Sunday.