Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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638
FXUS63 KOAX 290446
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1146 PM CDT Wed Jun 28 2017

.SHORT TERM...(Tonight through Saturday)
Issued at 444 PM CDT Wed Jun 28 2017

Nose of mid-level jet streak moving across Nebraska
evident on recent water vapor loop. Theta-e axis runs
from Des Moines to Concordia. Isolated severe storms developed
rapidly in southwest Iowa where SBCAPES 3500-4000 J/kg and bulk
shear values 50kts.

A tornadic storm is rooted on boundary and continues to push
east. Given little in the way to interrupt inflow and
the storm and given it`s developing on the nose of ULJ
jet streak, do not expect it to dissipate.  Additional
development to the southwest of leading storm, along
aforementioned theta-e axis.

Storms expected to continue to persist until mid-evening, then
models build upper level ridge into Nebraska, and that may
suppress convection.  Lull will be short-lived, as short wave
advances out of Rockies aft 06 UTC. Cold pool action will
determine how far south surface theta-e activity will push this
evening; however, with approaching wave, likely will see storms
to continue percolating across southern Nebraska and southwest
Iowa fed by persistent isentropic lift.  There may be a brief
lull in activity on Thursday morning due to mesoscale subsidence.

Boundary remains quasi-stationary on Thursday, and more potent
upper level wave moves out into central plains.  Deterministic
and ensembles all develop storms along lingering boundary and
additional developing expected along psuedo warm front
across northern NE. H5 westerlies and H8 southwesterlies will
allow storms to persist into the overnight. Expect storms
to diminish Friday morning, with a reprieve lasting into
Saturday.

.LONG TERM...(Saturday night through Wednesday)
Issued at 444 PM CDT Wed Jun 28 2017

Bulk of weekend looks dry, though moist southerly flow
and warm temperatures will allow for isolated diurnal convection.
MCS development late Sunday into Monday, will be the next
possible threat of severe weather. GEFS developing weak upper
level ridging over the area late Monday, though a few members
also showing an undercutting trough. Due to mixed signal,
cannot get too bullish on PoPs at this time. Due to increased
H5 ridging, temperatures rising a little above normal.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1142 PM CDT Wed Jun 28 2017

VFR conditions are forecast outside of any thunderstorm activity
at all eastern Nebraska TAF sites. Scattered storms early in the
TAF period should remain south of KLNK. Then an area of storms is
expected to track east across southern Nebraska, reaching KLNK and
KOMA between 13Z and 17Z. Brief MVFR or IFR cigs/vsbys could
result. Then more thunderstorms are forecast along a cold front
dropping southeast in the afternoon. Storms could affect KOFK as
early as 19Z, then KOMA and KLNK by 21Z. Expect several hours of
potential storms at each site, with attendant MVFR/IFR conditions.

&&

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

$$

SHORT TERM...Fortin
LONG TERM...Fortin
AVIATION...Dergan



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