Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 220440
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1140 PM CDT SAT MAY 21 2016

.SHORT TERM...(tonight through Tuesday)
Issued at 315 PM CDT Sat May 21 2016

Thunderstorm chances/intensity the next few days will provide the
main forecast challenges.

Large scale still shows an amplified mid level pattern with split
flow. Closed low at 500 mb was over Oregon...a ridge was over mid
America and another trough was over the eastern part of the CONUS.
A weak shortwave trough in north/northwest flow in combination
with lower tropospheric warm air advection helped produce some
isolated to widely scattered showers over parts of the area last
night and today. Short range high resolution models tend to show
that activity ending...with more isolated activity possible this
evening and tonight over the southwest parts of the forecast area.
Generally felt that better chances for significant precipitation
tonight and Sunday would stay farther to the west... but axis of
highest precipitable water does move into our area on Sunday.

Tonight...forecast soundings show a decent amount of moisture
in the 800 to 700 mb layer...with modest lapse rates above that.
If there was a stronger forcing mechanism...would be more
confident with rain chances.

Instability increases in our area Sunday...but best focus for
convection is farther west. Will keep some low pops going Sunday
evening but things look better after midnight as cold front moves
eastward. That front will likely help focus precipitation into
Monday and Tuesday. There does appear to be some potential for
severe storms Sunday night into Monday.

High temperatures through this period should be mostly in the mid
70s to lower 80s...with lows 55 to 65.

.LONG TERM...(Tuesday night through Saturday)
Issued at 315 PM CDT Sat May 21 2016

Pattern starts out with a trough extending from Saskatchewan back
to off the California coast. The southern part of the trough will
progress eastward toward the high plains by late week...and our
area should remain in southwest flow aloft. The GFS and ECMWF are
in good agreement with that. At the surface...a frontal boundary
is expected to be somewhere over or south of the region. Models
are not in good agreement with details of the frontal location.
Thus...like the past few days...felt compelled to keep at least
some mention of thunderstorms through the period. It will not be
stormy every day...but it will be very difficult to have high
confidence. Potentially...Tuesday night could be the most active.

Highs will be mostly in the 70s to lower 80s and lows still in the
55 to 65 range.

&&

.AVIATION...(06Z TAFS for KOMA...KLNK...KOFK through 06Z Monday)
Issued at 1137 PM CDT Sat May 21 2016

VFR conditions are forecast at eastern Nebraska TAF sites through
Sunday evening. Scattered to broken clouds at or above FL060
should prevail through at least 00Z. Some lowering of cigs is
likely between 00Z and 06Z when MVFR conditions could approach the
KOFK area. Though an isolated shower is possible, any significant
precipitation will remain west of TAF sites during the period.
Southeast to south winds will increase into the 15 to 25kt range
during the 16Z to 00Z period.

&&

.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&

$$

SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Dergan



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