Area forecast discussion
National Weather Service Goodland Kansas
523 am MDT Tuesday may 21 2013
Short term...(today and tonight)
issued at 223 am MDT Tuesday may 21 2013
500 mb low will remain over the eastern Dakotas today...and will
finally move east tonight. Model soundings continue the trend of
drying the low levels across the forecast area today. A weak
vorticity lobe will move across the northern part of the area during
the day. Even with upward vertical motion...the air mass will be
dry and increasingly stable enough to leave out precipitation chances.
The surface pressure gradient will be aided by decent northwest flow
at 850/700 mb to produce winds much like yesterday...20 to 35 knots.
Middle level ridge will develop late tonight over the High Plains for
continued dry.
Long term...(wednesday through monday)
issued at 223 am MDT Tuesday may 21 2013
The 500 mb ridge will strengthen Wednesday. Subsidence and lack of
low level moisture will produce dry weather. Weak warm air advection
will raise temperatures a few degrees Wednesday afternoon as surface
winds gradually become southeast in the afternoon. The GFS develops
some precipitation across eastern Colorado Wednesday night in a weak
warm air advection region. The air mass will be stable...however...
and expect low level moisture to be limited...so will keep the
forecast dry.
The ridge will shift east Thursday...and models bring a short wave
trough across northeast Colorado Thursday afternoon. Although the
air mass will continue to be stable and low level moisture will be
slow to return...will indicate a chance of showers by the afternoon
due to the implied lift with the short wave.
A shortwave trough embedded within a nearly stationary upper level low
over the Pacific northwest will influence our weather Friday. In
response...low level southeast flow strengthens and trajectories
favor a continued increase in low level moisture to the High
Plains Friday. Differences in medium range models appear by the
weekend. The European model (ecmwf) is furthest west with the Pacific northwest
upper low and retrogrades the upper level ridge westward placing
its axis over the forecast area Saturday and Sunday. The GFS and
Gem are further east with the position of both features keeping
our area in southwest middle/upper flow with the likelihood of weak
embedded shortwaves during this period. Isolated to scattered
showers and thunderstorms are possible each day through the
weekend and into the first part of next week. Coverage will depend
on exact timing and placement of embedded difficult to resolve
shortwaves in southwest flow aloft.
&&
Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 523 am MDT Tuesday may 21 2013
Surface winds are already 15-25 knots at kgld. With decent mixing
and moderate winds aloft...will indicate 20-35 knot winds at
kgld/kmck after 15z. Otherwise...expect some middle level clouds to
move over both sites...but conditions will be VFR.
&&
Gld watches/warnings/advisories...
Kansas...none.
Colorado...none.
NE...none.
&&
$$
Short term...Mentzer
long term...Bowers
aviation...Mentzer
