Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 160444

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1144 PM CDT Mon May 15 2017

.SHORT TERM...(Tonight through Thursday)
Issued at 320 PM CDT Mon May 15 2017

WV imagery this afternoon showing a deep longwave trof over the
western CONUS with a closed off low/potent vort max currently
digging southward through southern CA heading toward Baja.
Meanwhile...surface low pressure was centered in eastern CO with
attendant thermal boundary extending northeastward into south-
central MN. Good moisture advection into the central Plains
continues per VWPs showing anywhere from 20-30kts just off the
deck. This, along with daytime heating has allowed quick
environmental destabilization with MLCAPE ranging 1500-2500 J/kg
over the region. Strong CAP though remains in place.

For tonight...appears that another round of convection will develop
this evening west of the CWA on the nose of strengthening low
level jet. Both HRRR/RAP13 show a small cluster of thunderstorms
initiating in western KS late this afternoon/early evening along
axis of boundary layer theta-E convergence/steep mid-level lapse
rates 8C/km. Activity is progged to push into the CWA then shortly
before midnight. And at this appears the brunt of
activity will push across the northern CWA.

Tuesday afternoon...western shortwave trof eventually bottoms out
just south of the 4-corners region with leeside cyclogenesis
ensuing. Both the NAM/GFS prog impressive thrust of gulf moisture
into the central Plains culminating in PWS increasing to 1.75".
Convection...once CINH weakens...will likely form on the edge of a
dry line extending from north-central Neb to western KS and
increase in areal coverage heading into the evening hours.

With impressively steep lapse rates over top stout low level
moisture...seems quite probable several storms will be large hail
producers during the early evening hours. In addition...a heavy rain
threat is on the table as well. Precipitation efficiency will be
relatively high given deep warm cloud layer/strong low level
inflow/high environmental moisture content coincident to 20-30
microbars of omega. Interestingly enough...both HIRES ARW/NMM show
storms transitioning to a bowing line over the CWA toward mid

Lingering wrap around precip looks possible on Wednesday as the
central Plains vort max pivots and lift through the CWA into the
upper Midwest.

.LONG TERM...(Thursday night through Monday)
Issued at 320 PM CDT Mon May 15 2017

Precip chances continue Thursday afternoon through at least Saturday
morning in association with a large and relatively slow moving
system ejecting out of the central Rockies before lifting into the
Dakotas then the upper Midwest. A cooler air mass is then progged to
push southward into the region in the wake of the exiting system.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1133 PM CDT Mon May 15 2017

Thunderstorms are affecting KOFK currently and may impact KLNK
around 06-09Z. Also, in wake of thunderstorms, winds are shifting
to more of a southwesterly direction and becoming quite gusty, and
that should continue for a couple of hours. Conditions should
improve by morning, with the potential for low-level wind shear at
KOFK/KLNK into the morning. Another round of showers and
thunderstorms is possible on Tuesday afternoon/evening, and have
hinted at potential with VCSH at KOFK/KOMA and VCTS at KLNK later
in the TAF period.




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