Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 211728
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1228 PM CDT Fri Jul 21 2017

.SHORT TERM...(Today through Sunday)
Issued at 320 AM CDT Fri Jul 21 2017

Heat headlines and storm chances are the main forecast concerns in
the short term.

Main jetstream at 300 mb extended northeast from northern CA to
north of the ND and Canada border then east/southeast across the
Great Lakes region. Ridge at 500 mb was over KS and OK eastward
into MO and AR. Hottest temperatures at 700 mb were to our west
over WY and CO.

The 500 mb ridge is expected to build eastward a bit today as the
shortwave trough over British Columbia tracks eastward. The
problem is that south/southwest low level winds should affect much
of the forecast area today, pushing temperatures to the mid or
upper 90s and possibly over 100. This may not be quite as favorable
for the recent high dewpoints though. One exception to this could
be across northeast NE.

Some shower and T-Storms that developed early this morning could
linger a bit past sunrise, and there could also be some late
afternoon storms there as well. Will leave current heat headlines
as is and let the day shift look to see if any changes may be
needed. Weak cold front should continue to sag southward tonight,
and some storms possible mainly along or north of that boundary.
Lows tonight across much of the area should drop to the lower or
mid 70s (but might stay in the mid or upper 70s southern quarter).

North or northeast winds on Saturday should allow for some cooler
air to filter in, with highs mostly 90 to 95. There is some
question whether or not the cooler and drier air will work down
across all of southeast NE, but for now will not extend the heat
headline for Saturday. Will keep some low thunderstorm chances for
Saturday afternoon into Saturday night for the far southern parts
of the forecast area, but left most areas dry. Sunday may be a few
degrees cooler than Saturday, and currently expect highs in the
upper 80s or lower 90s.

.LONG TERM...(Sunday night through Thursday)
Issued at 320 AM CDT Fri Jul 21 2017

At the start of this period, a 500 mb ridge will be over the
central and southern Rockies, with our area in weak northwest mid
level flow. That ridge is expected to build east through mid week,
allowing our temperatures to increase a bit, but then cool later
in the week as heights decrease.

Sunday night through Tuesday looks mainly dry, but then there will
be some low thunderstorm chances Wednesday into Friday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1208 PM CDT Fri Jul 21 2017

VFR conditions are expected thru the fcst pd. There is a chance
for isold TSRA though developing along a weak sfc boundary
drifting swd thru the area late this afternoon/evening. Given
areal coverage is in question...have opted for VCTS at all
terminals.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Excessive Heat Warning until 8 PM CDT this evening for NEZ034-
     044-045-050>053-065>068-078-088>093.

     Heat Advisory until 8 PM CDT this evening for NEZ011-012-015>018-
     030>033-042-043.

IA...Excessive Heat Warning until 8 PM CDT this evening for IAZ055-
     056-069-079-080-090-091.

     Heat Advisory until 8 PM CDT this evening for IAZ043.

&&

$$

SHORT TERM...Miller
LONG TERM...Miller
AVIATION...DEE



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