Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 181917

Area Forecast Discussion
National Weather Service Goodland KS
117 PM MDT Wed Apr 18 2018

.SHORT TERM...(Today through Friday)
Issued at 245 AM MDT Wed Apr 18 2018

Upper ridge will build across the area today and Thursday ahead of
a slow moving upper low in the Great Basin. Expecting mostly sunny
and dry conditions with temperatures slightly below normal both
days. Elevated fire weather conditions are expected both days as
well, with northwest winds today of 20 to 30 mph and south winds
on Thursday of 25 to 35 mph. Relative humidity will drop to as low
as 20 percent both days.

Upper low will move into the southern Rockies Thursday night and
emerge onto the plains on Friday. Rain chances will begin Friday
morning and continue through the early weekend. Best chances for
rain will be Friday afternoon and Friday night. Models have
continued the trend of lower QPF totals, with generally between a
half and one inch (including Saturday). Leaned towards cooler side
of guidance for Friday temperatures, with highs mainly in the 40s
due to clouds and precipitation.

.LONG TERM...(Thursday night through Wednesday)
Issued at 116 PM MDT Wed Apr 18 2018

The extended period starts off with a large, slow-moving upper low
tracking east over the Southwest U.S.  Meanwhile, upper ridging
exists over the Central High Plains.  Latest numerical guidance has
the system moving a little slower than previous runs which seems
reasonable given the low is closed.  The GFS continues its trend of
moving the system faster than the ECMWF or NAM and prefer a slower
movement.  One item to note is that this system is currently still
offshore, just now approaching the northern California and Oregon
coasts.  Future forecasts may ultimately converge on timing once the
system gets onshore.

The main influence from this system in terms of precipitation will
not be felt until Friday at which time the nose of a 120 kt jet at
250 mb rotates up into Colorado.  Rain will begin over Colorado into
far western Kansas Friday morning and overspread the rest of the
forecast area Friday afternoon and night.  Precipitation will linger
through much of Saturday but rainfall amounts will be lighter
Saturday.  The system will ultimately begin to move ESE on Saturday
once it emerges onto the southern Plains as a second strong upper
wind max rotates around the southern periphery of the low.

At this time the potential for snow appears minimal, and if any rain-
snow mix occurs it would be over parts of our Colorado counties.
There is not a lot of cold air with this system and a saturated
lower atmosphere will prevent much in the way of any wet bulb
cooling.  Latest precipitation totals for Fri-Sat indicate a general
3/4-1" liquid.

Once the upper low moves out Sunday, model solutions diverge
significantly, therefore confidence toward the end of the extended
period is quite low.  For example, at midday Tuesday the EC shows a
weak upper trough approaching the area while the GFS has broad


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1158 AM MDT Wed Apr 18 2018

VFR conditions expected for the TAFs. Northwest winds will begin
to decline in the next hour or so, becoming light this evening.
During the night a surface ridge will move through, turning the
winds to the southwest.




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