Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 241124
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
624 AM CDT WED AUG 24 2016

.SHORT TERM...(today through Friday)
Issued at 345 AM CDT WED AUG 24 2016

Forecast concerns for the short term will be chances of
thunderstorms through Friday and heavy rain potential later this
afternoon and tonight.

This first round of thunderstorms had pushed through the area and
drier air is making it into the northwest part of the county
warning area. For details on the rain overnight and hydrologic
concerns, see below. A few showers may try to re-develop in parts
of western Iowa.

Water vapor satellite imagery and upper air analysis shows the
complicated weather pattern with a closed h5 low over saskatchewan
and leading shortwave troughs from Minnesota into southwest Iowa
and another area of low pressure over Colorado into Arizona. The
h3 jet streak over the Dakotas is forecast strengthen and drop
southward with time as it pushes across the northern U.S.
Meanwhile...there is another jet segment from New Mexico into
Kansas and this strengthens and merges with the northern stream
jet by Thursday.

The resulting h5 pattern calls for the h5 low to track into
Manitoba today as the trough deepens over the plains and then
becomes more westerly as the trough heads into the Great Lakes
Thursday night. Another h5 develops over the Rockies Friday
deepening over the Western High Plains Friday night

The 45kt low level jet has veered and is now feeding into the
storms across Kansas...Missouri...Iowa. From 12-00z...this low
level jet weakens to 25kts and begins to increase again after 00z
across eastern Kansas and northern Missouri. Typically, this would
favor thunderstorms south of our area and this is again the case.
The surface front will be in southeast Nebraska and southwest
Iowa. The H85 front is complicated with the rich h85 dewpoints
south of the forecast area...however sufficient dewpoints for
storms linger south of I80 and gradually push south through
Thursday...then return northward Thursday night and Friday.

Favorable upper level divergence...and the approach of the
shortwave over Colorado combined with heating and residual
moisture lead to a chance for thunderstorm re-development south of
I80. The forcing is not as strong as last nights and the theta-e
axis is south of the forecast area, however will include
thunderstorm chances this area...with the highest pops closer to
the front. There is a 0-3km 35kt speed max into southeast Nebraska
at 00z and a 45kt max in northeast Kansas at 06z...so will need to
keep an eye on storms that form near the border for strong winds.

Although not as favorable...do maintain shower/thunderstorm
chances for through Thursday with that lingering moisture and
upper level support although we are on the cool side of the front.

Better shower and thunderstorm chances return Friday with decent
warm air advection and return of rich moisture ahead of the next
shortwave trough.

Highs today will be in the 80s with 70s for Thursday through
Friday.

.LONG TERM...(Friday night through Tuesday)
Issued at 345 AM CDT WED AUG 24 2016

Active pattern continues Friday night through Saturday night with
the passage of the mid tropospheric trough. Beyond Saturday night
thunderstorm chances will be more spotty. Highs Saturday through
Tuesday will range from the upper 70s to the mid 80s.

&&

.AVIATION...(12Z TAFS for KOFK...KLNK and KOMA.)
Issued at 625 AM CDT WED AUG 24 2016

Generally expect VFR conditions outside of any TSRA the next 24
hours. There are some ceilings of 3500 to 5000 feet around early
this morning and these clouds will affect KOMA. They could also
affect KLNK. Winds had shifted to northwest at all three sites and
will veer to more north later today. Felt there was enough of a
chance of TSRA to include a PROB30 group at KLNK later today.
Bulk of pcpn will probably stay south of KOMA and KLNK though.

&&

.HYDROLOGY...
Issued at 345 AM CDT WED AUG 24 2016

Rainfall amounts over the last day per dual-pol estimates were
from 5 to 8 inches near Blair. A public report of 5 inches was
received near Blair before 10pm and it was still raining in the
area. A large area of 1 inch to 4 inches was noted from east
central Nebraska into southwest Iowa. 4.79 inches fell at the
Kennard ALERT river gauge and 3.56 inches at the Chalco gauge.
Gretna had 3.19 inches. Omaha Eppley reported 1.2 inches and
Lincoln 0.17. Here are the NWS office we had 2.81 inches. The
ALERT gauge did not reach flood stage at Kennard, however it did
at Fort Street on the Big Papillion. Most of the local gauges have
dropped from their earlier rises.

With the band of storms in the morning in northeast Nebraska .5
to 2.5 inches was likely and Norfolk received 1.15 inches.

Concerns for later today and tonight should be focused farther
south...however with storms forecast for southeast Nebraska and
southwest Iowa...and parts of these areas had rains last night,
included them in the Flash flood watch per coord with DMX/EAX/TOP.

&&

.OAX Watches/Warnings/Advisories...
NE...Flash Flood Watch from 6 PM CDT this evening through Thursday
     morning for NEZ091>093.

IA...Flash Flood Watch from 6 PM CDT this evening through Thursday
     morning for IAZ090-091.

&&

$$

SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Miller
HYDROLOGY...Zapotocny



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