Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 252041
Area Forecast Discussion
National Weather Service Goodland KS
241 PM MDT Tue Apr 25 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 234 PM MDT Tue Apr 25 2017
Main forecast issue will be chance of precipitation through tonight.
Satellite showing a slow moving/closed off low over Wyoming.
Satellite and height fall analysis shows the southern end this
trough extending from this low has begun and will continue split off
and dig to the south.
Nam and Ecmwf were doing a little better than the Gfs and Canadian
on the upper level jet. The Canadian and Nam were starting the best
with the mid levels. Other output is tending to have features/lower
heights too far east.
For tonight...a few things to note that required some changes to the
previous forecast. First the 12z DDC sounding show a very deep and
dry air mass that will advecting into the area ahead of the upper
low over Wyoming and southern extension of that low. The southern of
portion of this trough is shown by the model output to be
splitting/cutting off further south and west than indicated
The high resolution output picked on that with keeping the northeast
portion of my area dry through tonight. So removed the pops from
that area. There is still enough mid level lift along with a
secondary/weaker left front jet segment that will affect the
southwest portion of the area from later this afternoon through the
As a result, reduced pops a little over the central of the area.
Maintained or increased pops slightly in the far west per the
output and reasoning given above. Most of the precipitation will
be done by late evening with only a lingering chance in the far
south that will end a few hours after midnight.
For Wednesday...ridging aloft and drier conditions will prevail
across the area for this period. Will have more sun but the air mass
will be cooler. Overall the temperatures will be a little cooler
than what is occurring today.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 238 PM MDT Tue Apr 25 2017
The main focus of the extended period will be the chances for
precipitation and colder temperatures Thursday through Sunday.
Wednesday night: With upper level ridging in place, the night looks
to be dry with lows in the mid 30s.
Thursday-Thursday night: Messy pattern as the system that will bring
us our weekend weather gets its act together. A series of impulses
will rotate through the area and bring us chances of rain and
thunderstorms. May see some of the rain change to snow in the pre-
dawn hours across western portions of the CWA. No snow accumulations
Friday-Sunday: This period is a fairly tricky forecast with the
event still 3 to 4 days out. The main player will be a strengthening
closed low that most models show dropping south from Wyoming into
the Four Corners region and then moving across Kansas from the
southwest to northeast. 12Z runs of the GFS and ECMWF are much
slower with the progression of this system from previous runs,
whereas the CMC moves it through more quickly. A quicker solution
would place the CWA on the backside of the system faster, resulting
in a quicker change over to snow for the region, but less amounts of
precipitation for the entire event. There is high confidence in this
weekend being cold and wet with most areas (especially along and
west of the CO/KS border) seeing some snow Saturday night into
Sunday morning. There is low confidence in (1) that any change over
to snow will occur Friday night or through the daytime Saturday, and
(2) in the amount of accumulating snow for the entire weekend due to
phase changes and soil temperatures currently in the mid 50s. Precip
should begin Friday afternoon and move out of the area during the
day Sunday from west to east. QPF values of 0.50-1.50 in., depending
upon the speed of the system, will be possible across the region.
As for temperatures, the entire area will see below average temps
from Thursday through Sunday night. Saturday will be the coldest day
with highs struggling to get into the 40s. MOS guidance is showing
temperatures that will probably require a hard freeze warning in
western portions of the CWA for Saturday night.
Monday-Tuesday: Temperatures warm back to near normal levels through
the period. There looks to be a chance of rain Tuesday afternoon.
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1141 AM MDT Tue Apr 25 2017
For Kgld...Through the rest of the afternoon, into the late evening
hours, vfr conditions are expected along with northeast winds of
around 15 knots. Showers will begin moving close to the sight
later this afternoon into this evening. However, model output is
not clear on how far east this precipitation with more guidance
keeping further west of the sight. So chose only to put in
vicinity showers. In the 03z to 05z time frame mvfr conditions
will develop and the winds will shift to the north at 17 knots
with gusts to near to 25 knots. Even when conditions become vfr
around 09z, those gusty winds will continue until 13z. After 13z
the winds will be sustained near 14 knots.
For Kmck...Through the first half of the period, mvfr conditions
are expected with occasional vfr conditions expected during the
mid afternoon hours. Shortly after 06z, vfr conditions will return
for the remainder of the period. North winds will increase to near
17 knots with gusts to near 25 knots. Those winds will stop
gusting around 14z with the sustained winds remaining near 16
knots through the rest of the morning.