Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 250446
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1146 PM CDT Sat Jun 24 2017

.SHORT TERM...(Tonight through Tuesday)
Issued at 325 PM CDT Sat Jun 24 2017

Long wave trough positioned over eastern North America
will dominate the sensible weather across the region through
the short term. A series of short waves will rotate around the
periphery, with a quasi-stationary jet core anchored over the
mid-upper Mississippi Valley. Channeled nature of short waves do
not bode well for moderate to strong forcing, but jet dynamics
could generate transient bands of showers/sprinkles. Caveat is
large scale surface ridge will limit large scale moisture
advection, so will keep forecast tonight into Sunday dry for now.
Moist, isentropic ascent increases late in the period late, as
surface ridge moves east and more potent short wave carves long
wave extent of long wave. Not much in the way of instability, so
continued previous forecast trend of mentioning only showers for
Sunday night. Warming temperatures and increased moisture
advection on Monday, will increase instability, though SBCAPE
values still less than 1000 J/Kg. As such, broadbrushed chance of
isolated storms.

Another cool night temperature-wise, with mostly clear skies and
low level cold-advection. Low temperatures will be at or near
those seen Saturday morning. Low-level CAA continues into Sunday,
with less deep mixing expected, as such maximum temperatures
likely will be slightly cooler. Downslope warming may counter
across western CWA. Sunday min temperatures likely to occur early,
as surface flow returns to a southerly direction. Backed flow will
keep temperatures from rebounding too much on Monday, but expect
max temps to be a couple degrees above those seen on Sunday.

.LONG TERM...(Tuesday night through Saturday)
Issued at 325 PM CDT Sat Jun 24 2017

H5 ridging builds over central plains on late Monday into Tuesday,
and will allow temperatures to rise at or slightly above seasonal
norms for Tuesday. Ridge begins to flatten by mid week, as short
wave swings across southern Canada, and helps develop broad
trough across CONUS through the rest of the forecast period.
Various short wave features will affect the area, through the
forecast period. Deterministic and ensemble models fairly
consistent with timing and strength through Thursday, but then
ensembles showing quite a bit of spread late Thursday into
Saturday.

First glimmer of storms arrives Tuesday night with the possibilty
of storms that develop across western high plains moving into the
area, sustained due WAA/isentropic ascent. Limiting factor will
lessening moisture and increased stability as storms move into
eastern Nebraska and western Iowa.  Better chances will occur
Wednesday into Thursday, as surface front moves through the area.
Low and large scale flow becomes southerly, and that too should
increase moisture availablity. Exact timing, location and
intensity still questionable thus will keep PoP only in high
chance categories. Storm chances Friday-Saturday look probable,
but phase differences H5 pattern in ensembles, not generating
a clear solution.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1145 PM CDT Sat Jun 24 2017

VFR conditions are expected through the period.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...Fortin
LONG TERM...Fortin
AVIATION...Kern



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