Area forecast discussion 
National Weather Service Omaha/valley NE 
619 PM CDT Monday may 30 2016 


Short term...(tonight through thursday) 
issued at 329 PM CDT Mon may 30 2016 


Chance for thunderstorms through Tuesday early evening is the 
primary forecast concern in the short term. 


Main driver for thunderstorms later tonight and Tuesday is a short 
wave diving into northern Montana this afternoon and associated cold 
front that will swing through our warning area late tonight and 
Tuesday. Ahead of those features, a weak perturbation was noted on 
water vapor imagery and rap analysis from eastern Nebraska into 
eastern Oklahoma. More pronounced forcing was well to our south 
where storms had bubbled up in Kansas and Missouri earlier this 
afternoon. But several runs of various short range hi-res model 
output have suggested convection will fire this afternoon farther 
north in our southeast cwa, and indeed that has happened. Mixed- 
layer cape from rap analysis indicated 3000 j/kg bullseye in far 
northwest Missouri with Cape Ridge noted along middle Missouri 
River valley region. Shear profiles are pretty tame in this area, 
with a slow northeastward drift to activity. Expect storms in 
southeast Nebraska and southwest Iowa to continue to bubble up 
late this afternoon, and given high cape environment, could see a 
few strong storms with hail the primary threat, though a brief 
strong wind gust could happen with collapsing storms. Hrrr/rap 
show storms diminishing with loss of daytime heating, so have a 
decrease in activity represented in grids this evening. 


Attention then turns to storms along approaching cold front. That 
front is slated into northeast Nebraska by around 06z as short wave 
rolls into the northern plains. Forecast soundings from NAM/GFS show 
1500 j/kg of elevated cape will be in place ahead of this boundary, 
but shear profiles are lacking across eastern Nebraska with stronger 
mid level flow closer to short wave well to the north. While there 
will still be some severe risk past midnight, chances will become 
increasingly lower as storms become more and more elevated with 
time. 


Front will lose its southeast momentum late tonight and Tuesday and 
only slowly drift through our southeast County Warning Area by late afternoon. 
Scattered showers and storms will continue along and behind the 
front through the day, with best, albeit slight, chance for severe 
in the afternoon over southeast Nebraska and southwest Iowa where 
highest Theta-E surface air will reside. Again mainly vertical storm 
structures are expected given low shear environment, thus hail and 
downbursts are possible. 


Front should sweep precip chances to our south and east Tuesday 
evening. Much of the rest of the short term period will be dry as 
heights slowly rise in wake of exiting northern plains short wave. 
There is a small chance for convection Thursday as a weak impulse 
induces mid level warm advection regime over returning surface 
moisture in northeast Nebraska. Have included a slight chance for 
storms there on Thursday. 


Otherwise temperatures should average the 70s for highs through 
Thursday, with Tuesday and Wednesday favoring the low to mid 70s 
when clouds/precip/colder airmass are in place, then mid to upper 
70s Thursday as south to southwest winds return. 


Long term...(thursday night through monday) 
issued at 329 PM CDT Mon may 30 2016 


Another short wave and cold front moving through the region Friday 
will bring our next chance for thunderstorms, with the rest of the 
weekend looking dry. 


A quasi-zonal flow regime will be in place to begin the longer term 
period before an impulse emerges from the northern rockies and moves 
across the northern plains on Friday. This wave will push another 
weak cold front into the Central Plains on Friday, providing a focus 
for storms then. Again better forcing will reside nearer short wave 
in the Dakotas, but modest moisture return and heating ahead of 
front will provide plenty of fuel for at least scattered storms. GFS 
indicates surface based cape over 2000 j/kg with 35kt of 0-6km bulk 
shear. Will maintain our chance for storms Friday into Friday night 
before front sweeps southeast. Then northwest mid level flow takes 
over for the weekend, bringing a mainly dry forecast. 


Temperatures will likely surge well into the 80s on Friday before 
moderating into the 70s or lower 80s for the weekend. 


&& 


Aviation...(00z tafs for koma...klnk...kofk through 00z wednesday) 
issued at 611 PM CDT Mon may 30 2016 


VFR conditions will be in place for most of the taf cycle. 
Thunderstorms may affect kofk in particular between around 06-09z, 
but coverage is less confident later in the night as the line 
approaches koma/klnk. There is a better chance of storms for those 
sites beginning in the early afternoon, with the cold front 
nearby, continuing through later afternoon. With lower confidence 
in timing a more precise window for storms, have used prob30 
wording for now at those sites. Winds should remain around 10kt or 
less, shifting from southerly/southwesterly ahead of the front to 
northwesterly/northerly behind it. 


&& 


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


$$ 


Short term...dergan 
long term...dergan 
aviation...Mayes 






National Weather Service Glossary of Abbreviations
Back to forecast page
Non-Expanded Version (with abbreviations)

Units: English | Metric

Find the Weather for any City, State or Zipcode, or Country:

U.S. State List | Severe Weather | Tropical Storms | Ski Conditions
United States | Canada | Central America | South America | Asia | Europe | Australia | Africa | Islands

Weather Underground

© Copyright 2016
The Weather Company, LLC