Area Forecast Discussion
Issued by NWS Goodland, KS

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259
FXUS63 KGLD 231959
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
159 PM MDT Sun Apr 23 2017

.SHORT TERM...(This afternoon through Monday)
Issued at 158 PM MDT Sun Apr 23 2017

Upper level ridge extends across the Central High Plains, with
southwest flow beginning to build into the Central Rockies. At the
surface lee trough has developed across eastern Colorado, with high
pressure with southerly gradient in place over our CWA.

A weak mid level shortwave trough/pulse of positive vorticity
rotates through the region late tonight and another shortwave trough
moves through the region Monday afternoon. The surface trough shifts
southeastward with an approaching cold front late Monday afternoon.
Despite at least some instability and forcing, a substantial dry
layer below 500 mb (and later 600mb) will keep conditions dry. Main
impact of these shortwave troughs will be periods of high clouds
especially Monday afternoon. GFS/SREF does show a weak precip signal
Monday (mainly north), but other guidance keeps dry conditions in
place through Monday afternoon.

A strong LLJ develops tonight, and will gusty winds through the
night. This increased mixing and the moderation in air mass will
result in unseasonably mild lows in the 40s (possibly around 50).
High temperatures Monday will depend on where surface trough axis
sets up, but all indications are we will see above normal highs at
least in the lower 70s behind surface trough and low to mid 80s
ahead of surface trough axis.

Regarding fire weather potential Monday: Current models show the
strong LLJ ahead of surface trough transitioning eastward and a
weaker LLJ rounding the back side of the shortwave trough in the
north. Position of surface trough will tend to limit surface
gradient in regions of our southwest that have best chance for sub
20% RH, and with very little wind to mix down in the afternoon in
these locations we are unlikely to see even "elevated" fire weather
conditions unless the send LLJ shifts further south (current trends
do no favor this). Models are also showing an increase in Tds with
minimal decrease from the west, so current trends keep lowest RH
above critical criteria even in our far southwest CWA.

.LONG TERM...(Monday night through Sunday)
Issued at 106 PM MDT Sun Apr 23 2017

Upper trough will come out of the Rockies in several pieces Monday
night through Tuesday night, bringing chances for showers and
isolated thunderstorms. Instability is very limited, so not
expecting any severe threat. Will get a brief respite in
precipitation chances on Wednesday before the next system begins
to impact the region beginning Wednesday night. This is also a
very broad system which will takes its time moving out of the
Rockies and across the Plains in several pieces. The GFS does not
kick out the main upper low until Sunday, when it will be quite
wound up and might have enough cold air on the backside for a
chance of light snow.

Temperatures this period will start out near normal but by mid
week be below normal and by late week much below normal. Freezing
temperatures will be possible Saturday and Sunday mornings.
Primarily a light freeze is forecast by the models at this time,
but might get close to a hard freeze in northeast Colorado.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1120 AM MDT Sun Apr 23 2017

VFR conditions will continue through the TAF period with only
passing high clouds. South winds gusting 25-30 kt will slowly
decrease late tonight and shift to the southwest and then
northwest as surface low pressure moves across the region.
Strongest winds at the surface will tend to be this afternoon and
again late Monday morning. A strong LLJ will bring low level wind
shear to both KGLD and KMCK terminals late this evening through
14Z before this weakens and transitions east.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...024
AVIATION...DR



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