Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 161124

Area Forecast Discussion
National Weather Service Des Moines IA
524 AM CST Thu Feb 16 2017

.SHORT TERM.../Today through Tonight/
Issued at 312 AM CST Thu Feb 16 2017

A weak surface trough currently draped across Iowa will lift slowly
northeastward today as an effective warm front. It may not quite
exit our northeastern counties, where temperatures will remain
relatively cooler but still well above normal. Across the remainder
of the forecast area temperatures will rebound rather significantly
from the previous couple of days, aided by warm air advection on
modest southwest breezes. Highs will be in the lower 60s across
about the southwest third of the area, and this is only a harbinger
of things to come in the subsequent days, as discussed in the long
term section below. Tonight the boundary will continue to lift
northeastward, with light southwest flow across the entire forecast
area mitigating radiational cooling and resulting in overnight lows
in the 30s.

.LONG TERM.../Friday through Wednesday/
Issued at 312 AM CST Thu Feb 16 2017

Little changes to the going forecast, with the well above average
temperatures the main focus through the mid/long range. Westerly to
southwesterly flow in the lower levels with H85 temperatures
climbing into the mid teens celsius across the state for Friday
suggest the continued expectation of near record or record temps
into the mid to upper 60s across the CWA. Coolest location expected
to be around KMCW area where could still have a small amount of snow
left Friday. Any remaining snow likely to melt Friday, with ground
moisture still expected that can help limit warming as well.

Upper level ridge to move eastward Saturday with a weak cool
front/sfc trough axis moving through the CWA Friday night with high
pressure in place at the surface Saturday. Even though slightly
cooler temps expected, still should see max temps into the mid 50s
to mid 60s across the CWA. Thermal ridge then building back
northeastward through the region Sunday as more amplified upper
level ridging builds aloft. Strong southerly flow off the Gulf to
nudge from the central High Plains into Iowa late Sunday into Monday
ahead of an upper level trough digging through the intermountain
west. The associated surface low to push through the plains with the
waa continuing into Monday and chances for rain moving through the
CWA. Cold front to sweep through the state late Monday into Monday
night, with really little push of cold air behind the front. Have
more of a zonal flow pattern into the middle of next week, but still
mild air in place and well above average temperatures expected to
continue. Slightly stronger cold front to get hung up across the CWA
late Wednesday and just beyond the current forecast period which
could bring the chance for some rainfall and colder air back into
the region to end the week.

Given the snowmelt across the north, the extended period of warm
temperatures, and the chance for rain into Monday, may see some ice
jam potential across rivers in northern IA. Will continue to monitor
in the coming days for any issues. Given the warmer winter, depth of
ice on area rivers may not be too thick which will limit the
potential for ice jams as well.


.AVIATION.../For the 12Z TAFS through 12Z Friday morning/
Issued at 524 AM CST Thu Feb 16 2017

VFR conditions are expected through the TAF period with only high
clouds around FL200-300 and no precipitation. Winds will shift
from southeast to southwest today, but generally at speeds of
around 10 knots or less. There may be some light fog early Friday
morning, toward the end of the TAF period, but the probability and
potential intensity are far too low for TAF inclusion at this





LONG TERM...Beerends
AVIATION...Lee is the U.S. government's official web portal to all federal, state and local government web resources and services.