Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Omaha/valley NE
1132 PM CDT Tuesday Jun 30 2015

Short term...(tonight through friday)
issued at 256 PM CDT Tuesday Jun 30 2015

Tonight

Early afternoon water vapor imagery indicated potent shortwave trough
over ND. This system and associated forcing for ascent will be
spreading southeastward over the next 18 hours. Ahead of this forcing...850 to
700 mb warm air advection had led to a band of -ra from eastern South Dakota into western Iowa. This
band will likely to continue to slide southeastward through the eastern County Warning Area into the
evening hours within this zone of isentropic lift. By early to middle
evening are likely to also see some increase in showers and maybe a
few thunderstorms over southern South Dakota into northern Nebraska as the better qg
forcing starts to move toward the forecast area. Latest objective analysis
indicates that the better instability is along our far western County Warning Area
where 1000-2000 j/kg of MLCAPE resides...and this appears where the
best chance of thunderstorms will occur this evening. The precipitation is
expected to increase in coverage through the late evening as it
spreads southeastward with models indicating that best vertical motion moving
through the forecast area for a couple hours on either side of midnight. The
showers and isolated thunderstorms and rain then should decrease in coverage late in the
night as the forcing starts to shift southeastward.

Wednesday through Friday

The upper wave moving through the region will be exiting Wednesday
morning...but a few lingering showers could occur in the morning
along the Missouri River corridor. There isn't substantial forcing
for Wednesday afternoon...but instability could allow isolated
thundershowers to pop up...again along the Missouri River...but
not expecting anything substantial.

The next wave moves out of the northern rockies Wednesday night
affecting northeast Nebraska...then moves into the area on
Thursday with additional rain chances that linger into Thursday
night. By Friday...that wave could be past the area resulting in
dry conditions...but we could also still be within the cyclonic
flow to allow some instability thundershowers to pop up again
Friday afternoon.

Long term...(friday night through tuesday)
issued at 256 PM CDT Tuesday Jun 30 2015

Weak ridging in place across the region early in the period. The
European model (ecmwf) is generally dry through the weekend...but the GFS still
showing weak ripples affecting at least eastern Nebraska.
Confidence is low for the weekend...and will maintain just slight
chance probability of precipitation Saturday/Sunday. Temperatures seem very seasonable in the
80s with no oppressively hot weather expected. A strong wave and
associated front could move into the area Sunday night through
Monday with a better chance of rain during that time. That wave
could move out of the area...or it may hang up along the NE/Kansas
border for Tuesday...but again confidence is low that far out.

&&

Aviation...(06z tafs for kofk...klnk and koma.)
Issued at 1130 PM CDT Tuesday Jun 30 2015

Widely scattered thunderstorms will track across eastern Nebraska
and southwest Iowa through about 12z with pockets of MVFR visibility
possible with stronger storms. VFR conditions expected outside of
convection and extending through the remainder of the period.

&&

Oax watches/warnings/advisories...
NE...none.
Iowa...none.
&&

$$

Short term...boustead/Dewald
long term...Dewald
aviation...fobert

National Weather Service Glossary of Abbreviations