Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 220900
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
300 AM MDT THU SEP 22 2016

.SHORT TERM...(Today through Saturday night)
Issued at 300 AM MDT Thu Sep 22 2016

Early morning RAP and satellite analysis show a large scale
trough over the western US, with a closed center near the
California/Oregon border. Ridging extends across the central US
into the Northern Rockies, with SW flow over the intermountain West.

Today-Tonight: A quasi-stationary front will remain either over the
northern part of our CWA or just north of our CWA complicating temp
forecast. WAA south of this feature should support highs in the 90s,
while north highs may struggle to reach the low 80s (depending on
cloud cover). Precip chances are minimal due to storm track to our
west, and a very dry/stable in place over much of our CWA. There is
a weak precip signal in high resolution guidance in our west
associated with elevated instability above dry adiabatic layer. A
few thunderstorms may develop and attempt to track northeast late
this afternoon and evening with steepening lapse rates near the
surface trough along the CO border ahead of front, but confidence
is low. I introduced slight chances in eastern CO for now.

Friday-Friday night: Large scale forcing increases with entrance
region of jet ahead of large scale trough transitioning over our
CWA. Dry line develops near the CO border and could act as focus for
possible thunderstorm development early in the afternoon Friday
before main period of forcing occurs Friday evening. Biggest question
is going to be low level moisture along/east of this trough and
impact on instability. NAM currently shows ML CAPE around 1500 J/KG
which could be sufficient for an elevated risk of severe
thunderstorms considering the very high shear values ahead of trough
(50kt+ effective shear values). Based on soundings if favorable CAPE
materializes we may see potential for thunderstorms to merge in a
cluster or squall line with a potential for a widespread severe wind
event. Severe hail may be a secondary threat at this point, unless
we see better CAPE profiles than currently advertised.

Other forecast issue of concern Friday would be potential for near
critical fire weather conditions in eastern Colorado as windy
conditions are expected (gusts 40-45 mph possible). There is enough
spread on Tds between models but good mixing may support RH values
dropping below 20 percent in our west (behind dry line). Will need
to monitor.

Saturday-Saturday night: Post frontal air mass with subsidence
building from the northwest should preclude precip chances in all
but our far east/southeast. Expect temperatures to return to near
seasonal normals (highs around 80 and lows in the 40s to the lower
50s).

.LONG TERM...(Sunday through Wednesday)
Issued at 227 AM MDT Thu Sep 22 2016

The long term period is looking to be dry for the entire period.
Yet, there are some major discrepancies between the GFS and EC. The
current model run for the GFS has an exiting deep trough impacting
the region through Tuesday night with a ridge building in behind it.
The EC is much different, with the bulk of that trough moving out of
the region Sunday and then developing a closed low off the trough
over the southwestern states. That closed low is embedded under a
ridge that is over the region. So as far as the models go, there is
little confidence in which one will hold true at this point. One
thing to mention is that Sunday and Monday nights could potentially
see temperatures drop into the mid to upper 30s in some locations.
Will keep an eye on this due to the possibility for a frost
advisory. Otherwise, high temperatures are expected to be in the 60s
and 70s through the entire period, which is about average or just
under for this time of year.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1127 PM MDT Wed Sep 21 2016

Main aviation concern will be the possibility of low clouds and
reduced visibility in fog overnight and into Thursday morning. A
cold front will sag southward tonight and both are expected to
develop in the post frontal low level upslope environment.
Conditions will gradually improve through Thursday morning.


&&

.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

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



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