Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 251910
Area Forecast Discussion
National Weather Service Goodland KS
110 PM MDT MON JUL 25 2016
Issued at 541 AM MDT Mon Jul 25 2016
Just completed an update. First had to raise pops a little in the
far eastern portion of the area due to the rainfall leaving slower
than expected. Also added patchy fog for a small portion in our
.SHORT TERM...(Today through Wednesday night)
Issued at 311 AM MDT Mon Jul 25 2016
Main forecast issue will be continued thunderstorm chances.
Satellite showing an amplified pattern over the Pacific. This
transitions a flat ridge over the southern half of the country with
progressive flow over the northern half.
At jet level...The Nam was a little better at the start than
everyone else. At mid levels...The Gfs and Canadian were doing a
little better than the Nam. The HRRR and Sref were doing the best on
the surface wind and pressure field. The Gfs and Canadian were doing
the best on the low level thermal field.
More importantly is model performance on yesterdays and tonights
precipitation event. Not only the 00z Nam but all the convective
allowing models, except for the HRRR showed little to no
precipitation/thunderstorm complex going across late yesterday
afternoon and night. Also the large scale output did not catch what
happened from yesterday afternoon through this morning. This really
significantly lowers my confidence at any of their output early on
due to the environment being drastically affected mesoscale affects
and a large area of rainfall.
Today/tonight...Look to have some lingering rainfall in the east
through mid morning. Then the rest of the day looks dry with
subsidence behind exiting complex and rising heights.
Light upslope winds through the day will be balanced by what looks
to be plenty of sunshine. As a result only made minor adjustments to
the high temperatures.
Only a weak shortwave trough is going across during the night. At
this time will have slight chance pops moving across the area but am
not optimistic of this.
Tuesday/Tuesday night...Heights rise through the middle of the day
in advance of the next shortwave trough. Shortwave trough approaches
the western portion of the area late in the day with the surface
focus still to the west of the area. This shortwave moves across the
area during the night but the models have different solutions on
this. At the same time, a right rear quadrant affects the area
during the afternoon and evening.
So will have a slight chance in the west late in the afternoon. Then
will have chance pops moving across the area during the night. Air
mass is warmer as southerly winds increase with plenty of sun. So
raised maxes a little.
Wednesday/Wednesday night...Heights rise behind whatever shortwave
trough/thunderstorms occurred during the previous night. Then a
complex mess happens after this. Models showing a number of
different waves moving through in the northwest flow aloft and they
poorly resolve the details. It looks like one shortwave moves across
in the afternoon, mainly affecting the eastern portion, and then
another shortwave approaches the western portion of the area later
in the afternoon then moves across the entire area during the night.
Will start out with slight chance pops for the afternoon then
increase pops over most of the area during the night but confidence
is below average. At this time this looks to be the warmest day of
the three, but considering the model differences am a little
uncertain about this.
.LONG TERM...(Tuesday night through Monday)
Issued at 107 PM MDT Mon Jul 25 2016
Western ridge strengthens as we head into Wednesday. As the ridge
builds, it will enhance the eastern trough and bring northwest flow
aloft to the CWA on Thursday and Friday. An unsettled pattern will
develop as a result of this flow pattern as a series of shortwave
troughs propagate between the western high pressure area and the
eastern trough. Guidance does not agree upon the timing or strength
of the troughs; however, a pattern emerges that supports afternoon
thunderstorm chances each day through Friday with convective
possibilities extending into the overnight hours as well.
The best PoPs are on Thursday afternoon/evening as a strong trough
moves across the region. Good low and mid-level lapse rates in the
presence of a strong theta-e gradient, CAPE values over 1600 J/Kg
(GFS), and shear over 50kt (GFS) will lead to possible severe
thunderstorms during the late afternoon and early evening.
High temperatures through Thursday will be near normal in the
upper 80s to lower 90s.
The ridge will begin to slide eastward on Friday and Saturday which
will flatten and speed up the pattern a bit. We will likely see
temperatures begin to rise above normal as the ridge moves across
the CWA with middle to upper 90s possible on Sunday and Monday. PoPs
decrease as heights increase and subsidence takes over as we head
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1131 AM MDT Mon Jul 25 2016
VFR condition are anticipated through the TAF period at MCK and
GLD. Isolated thunderstorms will move off the rockies and across
the plains late today, but are expected to dissipate as they move
east before they can affect the GLD or MCK TAF sites. With
residual low level moisture and mostly clear skies
overnight...some low clouds and possibly even some fog is expected
around the GLD site. Have only mentioned a brief period of low
clouds at GLD between 11-13Z as they should dissipate fairly
quickly following sunrise.