Area Forecast Discussion
Issued by NWS Goodland, KS

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000
FXUS63 KGLD 210844
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
244 AM MDT Fri Jul 21 2017

.SHORT TERM...(This evening through Friday)
Issued at 201 PM MDT Thu Jul 20 2017

Latest upper air analysis shows the ridge nearly stationary.  There
were a few weak disturbances in the upper level flow rotating around
the ridge.  At the surface a warm front was moving north into
Nebraska.  Behind the front temperatures were around 100 and winds
were breezy from the south.  Ahead of the front winds were from the
east and temperatures were around 90.

Added a mention of rain for tonight mainly west of the CO border.
During the evening a weak upper level short wave trough will move
over the west edge of the forecast area. Isolated to scattered storm
coverage may accompany this short wave trough. Dew point depressions
do lower below 500mb, but the environment is still quite dry. Am not
very confident of storm activity over the the CO counties, but
cannot rule out any storm activity. The majority of the storm
activity will remain west and north of the forecast area, rotating
around the upper level ridge over KS. Any storm activity will be
confined to the evening.

While confidence for storm activity is low, there is some
uncertainty as to how far east any storms will develop/move into the
forecast area. Most data supports storm coverage will be west of the
CO line, so have chances for rain mainly over the west, with a small
extension into KS and NE to account for any storms that may be
slightly further east.

The main threat with any storms that do form will be damaging wind
gusts.

Friday highs will be very similar to today.  This will cause heat
indices to be around 105 for the same counties that are currently in
the heat advisory.  To keep the message simple extended the current
advisory through the afternoon.  The main uncertainty with this will
be the possibility of dew points being lower than currently
forecast.  If this occurs heat indices will be around 100.

During the afternoon an upper level short wave trough will approach
from the west.  Accompanying the trough will be a weak cold front
and isolated to scattered storm activity.  These storms will move
into the forecast area from the west during the late afternoon.  The
main threat with these storms will be damaging wind gusts.

.LONG TERM...(Saturday through Thursday)
Issued at 239 AM MDT Fri Jul 21 2017

Monday and Tuesday: H5 high pressure will be situated to the west
with a very subtle surface trough to the southwest. Remnant theta-e
boundary will be in place, giving us a chance of thunderstorms
through the afternoon before pushing east as we head into the
evening. Relatively weak ridge axis moves overhead on Tuesday,
limited by a very strong upper low moving across Canada. This will
serve to dry things out across the entire CWA as subsidence will
prevail through the day on Tuesday.

Wednesday and Thursday: Model guidance begins to disagree as we head
into Wednesday with a general flattening of the ridge expected. The
GFS builds a very narrow H5 ridge axis well into central Canada,
thus pushing guidance toward higher temperatures across the Plains.
While this is not necessarily in disagreement with the Canadian and
ECMWF models, it is far more pronounced. At the H7 level, a
differnent story emerges with both the GFS and the Canadian
developing a strong trough in the lee of the Rockies. ECMWF develops
the trough as well; however, the signal is much weaker. There will
be a chance of thunderstorms for both Wednesday and Thursday
especially during the afternoon and evening. Instability will be in
place along with a weak shear profile, thus a few stronger to
marginally severe storms will be possible both days. Better chances
will encompass the western half of the forecast area on Wednesday
before shifting east on Thursday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1112 PM MDT Thu Jul 20 2017

VFR expected at both KGLD and KMCK through the TAF period. Only
concern might be thunderstorm chances late in the TAF period,
Friday night, but confidence in coverage is lacking at this point.
Scattered thunderstorms will develop in northeast Colorado Friday
afternoon and move around the periphery of the upper ridge into
northwest Kansas and southwest Nebraska Friday night.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 8 PM CDT this evening for KSZ002>004-015-016.

CO...NONE.
NE...Heat Advisory until 7 PM MDT /8 PM CDT/ this evening for
     NEZ079>081.

&&

$$

SHORT TERM...JTL
LONG TERM...TL
AVIATION...024



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