Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 010545
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1145 PM CST Tue Feb 28 2017

.SHORT TERM...(tonight through Friday)
Issued at 250 PM CST Tue Feb 28 2017

Forecast concerns this package will primarily be if thunderstorms
will hold east and south of the area...light precipitation
coverage/precip type this evening and if there will be enough
moisture for light precipitation Wednesday...then temperatures and
winds through the forecast.

Quite a variety of weather occurring in the Midwest both to the
east and southeast of the forecast area. Locally...the surface
cold front/wind shift is near Falls City with temperatures in the
60s there. Northwest winds with readings in the 30s and 40s
prevail under cloudy skies across the rest of the forecast area.

Showers developed last evening near the Missouri River and
thunderstorms developed just east of our forecast area in
southwest Iowa. Another round of storms developed later overnight
in central Iowa and produced some large hail in southern
Wisconsin.

The h5 longwave trough continues to deepen as it progresses across
the Rockies and this broad lift combined with upper level jet
support...mid-level shortwave trough energy...lower level warm
air advection/higher dewpoints and a strengthening 45-55kt low
level jet is reflected by increasing thunderstorm activity over
parts of Iowa and Missouri and echoes aloft increasing across
Nebraska.

The NAM/RAP did well on the convective precip this afternoon as
depicted by the thunderstorms racing across southern/southeastern
Iowa. Although there may be some sprinkles...the HiRes models
tend to hold off on any measurable precipitation until after 00Z
and tend to focus it over southeast Nebraska and southwest Iowa
southward...most of the other models continue to show a signal for
light precipitation...thus left in the chance pops for light rain
in...and likely pops in the evening for southeast Nebraska and
southwest Iowa. The 18Z NAM12 is farther north and heavier with
the precip...so this will need to be watched. The thunderstorm
chances this evening approach Falls City...however look to hold
out of our area. The 18Z RAP/HRRR continues to support likely pops
this evening.  Colder air does work into the system and although
it should mostly be rain...a rain snow mix or briefly changing to
snow could occur before ending overnight.

A second re-inforcing shortwave follows in behind the h5 trough
Wednesday...there may be some flurries or snow showers (mix) as
some cape...25j/kg were noted in the soundings. Due to low
confidence in moisture fields...will hold off on rain/snow showers
Wed. with that shortwave diving through as it may hold east of
the area.

Another clipper passes to the north Thursday and again the snow
should hold northeast of our area. Northwest winds increase with
these features both Wed. and Thursday...however as high pressure
settles in for Thursday night, they should become light and
variable. Highs Wed should be in the 30s and 40s...with
30s/40s/50s for Thursday.

South winds increase for Friday with warming into the 40s and 50s
with some clouds as a clipper passes to the north.

.LONG TERM...(Friday night through Tuesday)
Issued at 250 PM CST Tue Feb 28 2017

A mild and mainly dry pattern is forecast for Saturday and Sunday
with highs in the 60s with a few more 70s on Sunday. South flow
strengthens from the Gulf through the Plains Sunday...however at
this time the showers do not quite make it into the forecast area.
Lowering heights move into the Rockies and Plains...however there
are still some timing and strength challenges Sunday into Sunday
night. The surface low with the medium-range models is to the
north...thus precipitation chances are better across the Northern
Plains and the Upper Mississippi Valley and Great Lakes.
Temperatures remain above normal through Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1137 PM CST Tue Feb 28 2017

MVFR cigs will prevail through 12Z as mid level trough tracks
across the central plains. Conditions will improve to VFR between
12Z and 18Z as northwest winds increase across the area with lower
levels seeing a return of drier air. Clearing conditions then
develop by 00Z with loss of surface heating and extend through
06Z.

&&

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

$$

SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Fobert


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