Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 252339

Area Forecast Discussion
National Weather Service Goodland KS
539 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 00Z TAFS through 00Z Wednesday evening)
Issued at 539 PM MDT Tue Apr 25 2017

MVFR ceilings expected at both sites this evening/tonight as a
weak disturbance moves through. Anticipate conditions to improve
after midnight as drier air moves in. A few showers/isolated
storms are forecast, across primarily east Colorado. Can`t rule
out a shower/storm at KGLD. Confidence was too low to put in VCTS
so felt VCSH was more appropriate for now. Will monitor/amend in
case that changes. North winds become gusty for a period this
evening, then weaken some early tomorrow morning. Winds pick up
again at around 15z.




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