Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 112352
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
652 PM CDT Fri Aug 11 2017

.SHORT TERM...(This evening through Saturday night)
Issued at 218 PM CDT Fri Aug 11 2017

Aloft: 12Z upr-air data...aircraft data and GOES WV imagery
showed a high amplitude ridge over Wrn Canada with a broad trof
downstream over the cntrl USA. A small but potent low was dropping
down the E side of the ridge thru Alberta/Sask. WNW flow will
remain over the Cntrl Plns thru 00Z/Sun. The low will cont moving
S into MT and the Dakota`s.

Surface: Canadian continental air remains over the Cntrl Plns
along with 1022 mb high pres. Weak low pres was just N of MT. This
low will migrate S thru the lee trof tonight and tomorrow with
the high drifting E into the upr MS Vly.

Rest of this afternoon: Fantastic. Enjoy it. Temps svrl degs
cooler than normal with very comfortable humidity and light winds.

Tonight: Daytime cu will dissipate leaving m/clear skies...but
there will probably be a few patches of altocu and cirrostratus
drifting thru (blow-off from upstream tstms over the Rockies). Low
temps svrl degs cooler than normal.

Sat: Gradually increasing clouds. Sct tstms will develop to our N
and W ahead of the approaching low aloft...with the best chance
here at night. Right now this fcstr is skeptical on svr potential.
A continental/low dwpt air mass will remain in place and 09Z SREF
suggests MUCAPE will be 500 J/kg or less. Another cool day
expected.

.LONG TERM...(Sunday through Friday)
Issued at 218 PM CDT Fri Aug 11 2017

Pattern: Over the last 10 days...the mean trof has been over the
Ern 2/3 of the CONUS with the ridge along the W Coast. The 00Z EC
ensemble mean and the 00Z bias corrected GFS ensemble mean are
both fcstg the trof to shift back into the Wrn USA with a ridge
over the E next week.

The upr low referred to above will gradually transition from the
Dakota`s into MN. A ridge will arrive in its wake Mon with fairly
low amplitude flow after is passes Tue-Fri.

Temps: cont below normal thru at least Tue...then there appears to
be good potential for temps to return to near normal Wed-Fri.

Precip: Typical summer. There is potential for hit or miss tstms
each day/night...but most of the time (and most locations) will be
dry. Zonal flow can yield small embedded shortwave trofs that
could create a favorable environment for isolated or sct tstms to
develop and/or move into the CWA from the High Plns. However...
these are mesoscale details that cannot be determined far in
advance. The fcst may be overly optimistic on rain chances during
some time periods...as model-generated QPF could be based on
convective feedback (i.e. - models may be fcstg tstms to develop
based on the remnants of other tstms that may or may not actually
occur).

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 644 PM CDT Fri Aug 11 2017

VFR conditions forecast. -TSRA are an outside possibility for the
final few hours of this forecast, but more than likely just
outside of the realm of time of the forecast as some numerical
model solutions predict a squall line moving through.

&&

.CLIMATE...
Issued at 1244 PM CDT Fri Aug 11 2017

Thru the first 10 days of Aug...the average temp at GRI is 67.2F.
This is 8.2F below normal.

The average temp has been below normal every day so far this
month...and extends back to the last 6 days of July. Will add some
more days onto this thru the middle of next week.

As of midnight...this 10 day period ranks as the 2nd coolest start
to Aug on record (period of record 1896-present). Here at the top
5 coolest:

1) 65.8 1974
2) 67.2 2017
3) 67.9 1948
4) 69.8 1927
5) 69.8 1915

Of these 1915 went on to be the coolest Aug since records began...
but 1974 and 1927 went on to remain in the top 5 coolest.

It appears temps will return to near normal late next week. It
will be interesting to see where this month ends up in the record
books. It`s difficult to sustain this kind of anomalous cool even
as long as we`ve had it. So continuing it thru the 2nd half of
the month is very unlikely.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&

$$

SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Heinlein
CLIMATE...Kelley



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