Area forecast discussion
National Weather Service Omaha/valley NE
348 am CDT Sat may 25 2013
Discussion...
still expecting a potentially active weather pattern to develop
over our area in the coming days. Upper ridging overhead will
slowly shift east through Monday as low currently rotating through
New England gradually moves off the coast. Meanwhile...western
trough extending from a low in southwest Canada will send impulses
into the plains and eventually push toward the plains by middle to
late week. Plume of deep moisture currently from the Southern
Plains into the High Plains will also shift east over our area by
Sunday or Sunday night. So moisture under increasingly supportive
flow aloft suggests much of next week could be active.
For the rest of the weekend things are a little less clear.
Convection spreading through eastern Nebraska and into western
Iowa this morning was disrupting surface pattern...but models
indicate warm front will lie from western Nebraska into northeast
Kansas later this morning. That front should lift north during
the day after convection wanes...reaching the Interstate 80
corridor later today. Surface dew points in the 60s will follow
the warm front into southeast Nebraska today...then spread across
all of the County Warning Area overnight. While warm front may focus convection
later in the afternoon...instability will likely focus west of our
area where heating and moisture will be more robust. While some
storms could fire in the heat of the day in eastern
Nebraska...expect best chances will come overnight as low level
jet rides over frontal boundary and focuses best convection in
northeast Nebraska into west central Iowa.
All of eastern Nebraska and western Iowa should be in warm sector on
Sunday with surface dew points well into the 60s and warm nose at
or above 850mb capping most afternoon convection. Again better
chances will come overnight as afternoon convection firing in
western Nebraska propagates southeast toward eastern Nebraska with
increasing low level jet. Much of the same is expected Monday.
Lingering morning convection could redevelop late in the day...but
will likely hold off until the evening when low level jet kicks
in...with speed convergence pointing to best chances in the
northern County Warning Area.
Widespread severe storms do not appear likely through Monday.
Afternoon maximum instability axes will lie west of our area each
day where moisture/insolation will be highest. And middle level flow
will continue to be rather meager. Looks like best bet for severe
would come with mainly elevated evening/overnight storms helped by
low level jet.
Can not really rule out thunderstorms during any period for the rest
of the week Tuesday through Friday. However best chances for the
strongest storms appear to be Wednesday and Thursday when upper
low/trough moves into the northern plains and drives a cold front
toward our area. Stronger middle level flow and cooler temperatures
aloft will also be in place.
Dergan
&&
Aviation...06z tafs for koma...klnk and kofk.
The thunderstorms and rain in southwest and central Nebraska continued to develop
eastward late this evening. Expect that trend to continue for the
overnight hours. Will mention thunderstorms and rain at all three sites...with
some wind gusts around 30 knots at klnk. Trend should be for MVFR
and possibly IFR ceilings to develop with precipitation. These may last
into middle morning and then break up.
There will be some chance of thunderstorms and rain at all three sites 21z-03z
but confidence was too low to include in tafs at this time.
Miller
&&
Oax watches/warnings/advisories...
NE...none.
Iowa...none.
&&
$$
