Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 171728

Area Forecast Discussion
National Weather Service Omaha/Valley NE
Issued by National Weather Service Sioux Falls SD
1228 PM CDT Mon Oct 17 2016

Issued at 502 AM CDT Mon Oct 17 2016

Trimmed a little more of the dense fog advisory. It appears less
likely that widespread dense fog will affect Omaha/Council Bluffs
and Lincoln. Recent HRRR/HRRRX model runs suggested that. Will
continue the advisory farther to the northwest, including
Columbus, Norfolk and Wayne.


.SHORT TERM...(Today through Wednesday)
Issued at 330 AM CDT Mon Oct 17 2016

The primary forecast concerns again this morning are fog, drizzle,
low clouds and how much of an impact these will have on high
temperatures today.

Thermal ridge at 850 mb last evening was rather impressive for mid
October, with 25-30 degree C values extending from Mexico northeast
into Colorado and western Kansas. On the eastern edge of this warm
air, there was decent 850 mb moisture (dewpoints 12-15 degrees C).
The thermal ridge at 700 mb was a little farther east, with the
axis stretching into southeast Nebraska. 500 mb chart had decent
southwest flow from the eastern Pacific into the northern and
central Plains. Main feature at the 300 mb level was a band of
winds in excess of 100 knots (with one aircraft report of 165
knots) extending from off the coast of northern California into
northern Utah.

Current observations and IR fog satellite product show areas of
fog, mainly in parts of northeast and east central Nebraska into
parts of western Iowa. Will make some adjustments to the dense fog
advisory, generally trimming the southeast edge. Will also extend
this an hour or two depending on location. The central part of the
fog area should dissipate last, so will hang onto that until 11
am. The fog should decrease by noon. With a warm start and good
mixing with southwest winds, we look for highs mainly from the
upper 70s to mid 80s. Record highs for today at the main climate
sites include KOMA/84 - KLNK/85 - KOFK/89.

Winds will turn to the northwest as a weak cold front pushes
through the region tonight. Look for lows in the 40s in northeast
Nebraska and upper 40s to lower 50s in southeast Nebraska and
southwest Iowa. The cooler air should continue to filter into the
area through Wednesday with highs mostly in the 60s.

Forcing for ascent increases late Tuesday night into Wednesday,
 so will keep a mention of possible showers mainly for the
northwest half of the forecast area Wednesday. The GFS rain
amounts are probably a little high, but some spots could see
values approaching a tenth of an inch.

.LONG TERM...(Wednesday night through Sunday)
Issued at 330 AM CDT Mon Oct 17 2016

Some spotty showers may occur into Wednesday night, otherwise the rest
of this period looks mainly dry.

Mid tropospheric trough axis should move east of our area on Thursday
as a ridge develops from off the southern California coast up into
Saskatchewan. Through Saturday, that ridge will broaden and expand
eastward, allow our temperatures to moderate a little and reach back
above normal by Saturday.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1224 PM CDT Mon Oct 17 2016

Areas of low lying stratus will persist across northeast Nebraska
through mid afternoon as area of low pressure slowly lifts
northeast. As atmosphere decouples tonight, strong northwest flow
will develop on backside of the departing system resulting in low
level wind shear at 1500-2000 feet agl. This wind shear will
weaken after 07z, and continue to decrease through Tuesday morning
as high pressure builds into the area.




LONG TERM...Miller
AVIATION...BT/FSD is the U.S. government's official web portal to all federal, state and local government web resources and services.