Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

000
FXUS63 KOAX 232319
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
619 PM CDT FRI SEP 23 2016

.SHORT TERM...(tonight through Monday)
Issued at 318 PM CDT FRI SEP 23 2016

Impressive upper level closed system continues to slide east
through the Great Basin and into the central Rockies. Downstream
from this trough strong ridging aloft was allowing for a
seasonably hot, but capped atmosphere over the FA. Height falls
still start to spread into the high Plains this evening, and into
the mid Missouri River valley during the day on Saturday as an
intense 110 kt H3 jet rotates into the Dakotas. Warm-air advection
associated with a dynamic low-level jet will increase tonight, but
point forecast soundings generally indicate we will stay capped
tonight and will maintain a dry forecast through 11Z. After this
time the moisture profile appears to improve sufficiently for some
showers to develop. As the large-scale forcing for ascent
increases during the day on Saturday we will likely continue to
see a slow uptick in convection through the day. Although lapse
rates are not overly impressive, with surface dew point in the mid
and upper 60s coupled with 700-500 mb lapse rates of 6-6.5 C/KM,
we will likely develop around 1000-1500 j/KG of MLCAPE by
afternoon along and ahead of the cold front. As mid-level flow
increases to 35-45 kt across the boundary, point forecast
soundings indicate around 30 kt of effective shear. Thus we may
see some organization to the storms through the afternoon with
isolated severe possible. Given the hodographs and backing of the
mid and upper level flow through the afternoon it appears that
wind associated with line segments would be the greatest threat.

The cold front will slowly work off to the southeast on Saturday
night with the threat of some showers or maybe a few thunderstorms
continuing in southeast Neb and southwest IA. Most of this
activity should be south of the area on Sunday with brisk
northwest winds and much cooler air into the CWA. Mixing to 850 mb
yields highs in the upper 60s to lower 70s, and with the cold air
aloft we will likely see a good deal of SC. Some lows in the lower
40s are likely in the northwest on Sunday night as the surface
ridge axis develops toward the area. The cooler air will remain
over the area on Monday, but we should see more sunshine through
the day.

.LONG TERM...(Monday night through Friday)
Issued at 318 PM CDT FRI SEP 23 2016

As the Great Lakes trough starts to slide off to the east on
Tuesday/Wednesday we will see increasing heights aloft with
temperatures starting to warm to back to above normal. The global
models then start to move a system from the west into the Plains
toward the end of next week. The GEM/GFS are much quicker to this,
but we generally prefer the slower solution of the ECMWF. This
will bring back the chances for rain starting on Thursday night
and into the day on Friday.

&&

.AVIATION...(00Z TAFS for KOFK...KLNK and KOMA.)
Issued at 617 PM CDT FRI SEP 23 2016

Wind shear is possible at all sites later tonight into Saturday
morning. Showers may begin to affect KOFK by around 12Z, but more
widespread threat for showers begins in the afternoon and focuses
more on KOMA/KLNK. Have included a PROB30 mention for
thunderstorms in the afternoon. For now, have kept visibility in
the MVFR range and ceilings in the VFR range with that activity.

&&

.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&

$$

SHORT TERM...
LONG TERM...
AVIATION...Mayes



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.