Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Des Moines Iowa
1240 PM CDT Tuesday Mar 31 2015

Synopsis...
issued at 321 am CDT Tuesday Mar 31 2015

Low pressure east of Iowa will pull away as its associated cold
front stall today...then begins lifting north as a warm front.
Stronger low over Alberta will move east with a cold front
sweeping into Iowa late Wednesday into early Thursday. Pacific high
pressure will build in behind the cold front.

&&

Short term /today/...
issued at 321 am CDT Tuesday Mar 31 2015

A weak surface low passes to the east of Iowa overnight dragging a
weak trough and windshift across the state. Today weak surface high
pressure will drift across the state as the flow aloft remains out
of the northwest. The result will be a lighter wind out of the
northwest and with lighter wind and less mixing and a weak
northwesterly flow...temperatures will be a few degrees cooler today.
Soundings are dry though and the sun will be bright today and temperatures
will still be well above average so another sunny warm day is
expected.

Long term /tonight through Monday/...
issued at 321 am CDT Tuesday Mar 31 2015

Strong warm air advection will take place tonight into Wednesday.
Temperatures Wednesday are likely to be closest to the warmest guidance
solutions with good solar insolation through the day. Models are
in good agreement with the cold front entering the northwest in
the afternoon. Strong Theta-E advection with surface dew points
rising into the 50s will set the stage for thunderstorm
development during the late afternoon into the overnight. Decent
instability with about 2000 j/kg available during prime
time...though instability is lost reasonably quickly. With front
slowing down and 800 mb jet increasing to at least 50 kts...moisture
convergence is strong. Warm cloud depths increase to over 2500
meters with precipitable water values in in the 1.3 inch range...about 3 sigma
above normal for this time of the year. There is a severe
potential across the County Warning Area...but as the night progresses expect to
see more of a linear structure with isolated severe and heavy
rainfall. At this time do not feel rainfall will be enough to
cause flooding...but that will need to be monitored.

Cooler weather overspread the area Thursday after lingering
showers end. Cold front is not likely to get too far south of the
state with the southwest flow aloft continuing and mean trough
position over the western U.S. Rain will move back into the south
about Friday...and over the County Warning Area for Sunday into early next week.

&&

Aviation...31/18z
issued at 1237 PM CDT Tuesday Mar 31 2015

VFR conditions will remain in place throughout taf period. Winds
will remain around 8 to 12 kts today and diminish this evening.
Winds will be out of the south tomorrow and pick up siginificantly
by late morning and early afternoon...upwards of 20 to 25kts and
gusts to 30kts or greater.

&&

Dmx watches/warnings/advisories...
none.
&&

$$

Synopsis...MS Mar 15
short term...fab
long term...MS Mar 15
aviation...Curtis

National Weather Service Glossary of Abbreviations