Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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743
FXUS63 KOAX 260438
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1138 PM CDT Tue Jul 25 2017

.UPDATE...
Issued at 703 PM CDT Tue Jul 25 2017

The Heat Advisory was allowed to expire at 7 PM CDT. Temperatures
will continue to slowly cool through the rest of the evening.

&&

.SHORT TERM...(Tonight through Friday)
Issued at 319 PM CDT Tue Jul 25 2017

A mid to upper-level low over Manitoba will continue east into
eastern Canada while a series of lower-latitude impulses track
from the eastern Great Basin into the mid MO Valley late tonight
into Wednesday. In the low levels, a boundary stretching from the
ND-MN Red River Valley through south-central SD into wrn NE will
serve as the focus for strong to severe storms this afternoon into
evening. The nocturnal strengthening of a LLJ coupled with
increased forcing for ascent attendant to a lead impulse emerging
from the Rockies will sustain thunderstorms overnight, a subset
of which are forecast to move across the area through 12z/Wednesday.
Strong wind gusts and locally heavy rainfall will accompany the
most intense storms, though the nocturnal maximum in stability
will preclude the potential for an organized severe weather
threat.

Latest model guidances hints at a relative lull in convective
development from mid morning into early afternoon Wednesday with
an uptick in storm coverage and intensity along the southward-
moving cool front by mid afternoon. The extent and longevity of
the early-day storms will impact the degree of air mass
destabilization, as well as the location of the effective surface
boundary with the greatest risk for a few severe storms being
across southeast NE and southwest IA from mid afternoon into early
evening. Corridors of heavy rainfall (i.e. two to three inch
storm-total amounts) are possible, the locations of which will
likely be modulated by mesoscale features.

A surface high will build into the area Thursday and Friday,
yielding a cooler and drier low-level air mass.

.LONG TERM...(Friday night through Tuesday)
Issued at 319 PM CDT Tue Jul 25 2017

Medium-range guidance continues to advertise the re-
intensification of a long-wave ridge over western North America
during the long-term period with downstream troughing from Hudson
Bay to the Gulf Coast. Weak mid-level perturbations embedded in
northwest flow aloft will foster small chances for showers and
thunderstorms. Otherwise, it appears temperatures will remain
relatively mild with daytime highs near seasonal normals.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1140 PM CDT Tue Jul 25 2017

SHRA and TSRA will move across the KOFK TAF site early Wednesday
morning. Ceilings could drop to the MVFR category and possibly
lower for a brief period, with gusty winds around or over 35 kts.
MVFR ceilings also possible much of the daytime at KOFK. SHRA and
TSRA will move toward KLNK by about 10Z or maybe a bit earlier,
then toward KOMA by 11Z. Winds could gust to around/over 30 kts.
MVFR ceilings may occur in the heavier precipitation,

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

UPDATE...KG
SHORT TERM...Mead
LONG TERM...Mead
AVIATION...Miller



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