Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 240517

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1217 AM CDT TUE MAY 24 2016

.SHORT TERM...(tonight through Thursday)
Issued at 322 PM CDT Mon May 23 2016

Forecaster uncertainty remains high as several disturbances drift
into the region through the holiday weekend. It is hard to find any
12 hour period that has little to no chance of thunderstorms.

Initial wave of weak convection has pushed through the CWA and
second wave is beginning to show itself along a very weak low level
boundary. A weak shortwave currently over southwest Nebraska will
continue to drift northeast and approach the area. A very moist
boundary layer in addition to daytime heating has allowed an
instability axis to extend across the CWA with MUCAPE around
2000J/KG. Despite weak low level convergence, 40-45kts of deep layer
shear could be enough to sustain an isolated severe threat for
hail/wind. Also have a report west of our CWA of a brief landspout
tornado along this weak boundary. High-res CAMs continue isolated
convection along this area of weak convergence and then transition
it into an MCS across southeast Nebraska through the evening hours.

Much of Tuesday morning looks dry but pops are reintroduced again
Tuesday afternoon as a low pressure trough continues to deepen
across the central High Plains with continued southwesterly mid
level flow over our region. This will send a couple of shortwaves
into the area during peak heating where a continued very moist and
increasingly unstable airmass resides. Better focus for deeper
convection will be across the Nebraska panhandle in association with
a stronger shortwave trough. This activity could maintain itself and
spread east into Wednesday morning but many uncertainties remain.
PW`s remain very high and heavy rain continues to be a threat.

.LONG TERM...(Thursday night through Monday)
Issued at 322 PM CDT Mon May 23 2016

Forecast uncertainty remains high through the long term period as we
move into the holiday weekend. By Thursday night the primary mid
level shortwave axis will extend across eastern Colorado and drift
northeast across central Nebraska Thursday or Friday with the 12Z
operational ECMWF timing a bit slower than the 12z operational GFS.
In any case, lee side cyclone will deepen over eastern Colorado with
a northeastward extending warm front draping across the CWA Thursday
night into Friday. Instability ahead of this wave will be very
high and could lead to a fairly good shot for severe wx if timing
all works out.

Sporadic chances for scattered convection will continue through
Memorial Day weekend as several embedded shortwaves move through
southwesterly flow into the region.


.AVIATION...(06Z TAFS for KOMA...KLNK...KOFK through 06Z Wednesday)
Issued at 1214 AM CDT Tue May 24 2016

Thunderstorms will move east of KOMA and KLNK TAF sites early in
the period. Then a period of VFR conditions will occur before MVFR
cigs/vsbys overspread KLNK/KOMA...with some brief IFR vsbys in fog
possible between 10Z and 15Z. KOFK will likely see IFR vsbys in
fog during that time as well. Expect vsbys and cigs to improve to
VFR during 15Z to 18Z timeframe. The attention turns to the
potential for thunderstorms again Tuesday afternoon or evening.
There is some question exactly when storms will fire near TAF
sites, with the most likely time after 00Z.


.OAX Watches/Warnings/Advisories...


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