Area forecast discussion
National Weather Service Omaha/valley NE
337 PM CDT Tuesday may 21 2013
Discussion...
short term forecast concerns will primarily be showers...clouds
and cooler temperatures...then thunderstorms Friday and through
the Memorial Day Holiday.
At 12z...the 500 mb low was centered over eastern South Dakota and will
slowly shift eastward to southern Minnesota by 12z Wednesday and to
southern Wisconsin by 06z Wednesday night. Per the upper air maps...warmer
air is wrapped around the low...along with deeper moisture. This
was highlighted by the +8c temperatures and dewpoints at abr...however it
was only +3c at fsd. As a result...Theta-E advection over South
Dakota will spread into northern and then eastern Nebraska
tonight...with another round of Theta-E advection across South Dakota and Minnesota
Wednesday. The main area of rain over South Dakota and Minnesota
will remain to our north and east...however showers and will try
to develop southward into Nebraska overnight and Wednesday before
shifting off to the east late Wednesday. Will mainly focus chance
probability of precipitation in the north with isolated showers farther south and mainly dry
for the southern third of the forecast area through Wednesday.
Little diurnal range expected with the extensive cloudcover with
much below normal temperatures. Lows tonight mainly 46 to 51 and
highs Wednesday in the upper 50 near the South Dakota border to the middle and
upper 60s near the Kansas border. Lows Thursday morning should
drop back into the 40s with decreasing cloudcover.
There will be a break in the activity Thursday and Thursday night
as a large storm system affects the West Coast. We will see middle
level ridging Thursday and deeper moisture returning Thursday
night to the western High Plains. Highs Thursday should top out in
the 70s.
There will be an unsettled weather pattern through the weekend
with some periods of thunderstorms. Southwest flow aloft will lead
to waves of energy lifting through the plains Friday into the
weekend. Some thunderstorm chances continue into early next week.
The convection will be periodic...so even though we have a good
chance for thunderstorms into the Memorial Day weekend...temperatures
will be milder in the 70s and 80s and there will be a good amount
a rain-free periods as well.
&&
Aviation...
18z tafs for koma...klnk and kofk. VFR conditions
expected at koma/klnk...but likely becoming MVFR by 00-03z...which
should continue through the remainder of the forecast. Kofk will
likely remain MVFR through 00-03z...with spotty showers in the
vicinity of the taf site...then becoming IFR by 06-09z. Winds will
be west southwest...then northwest...with sustained speeds 12 to
15 knots...gusts up to 25 to 28 knots through 23-01z.
Dewald
&&
Oax watches/warnings/advisories...
NE...none.
Iowa...none.
&&
$$
Zapotocny
