Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 182340

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

.SHORT TERM...(This evening through Thursday)
Issued at 124 PM MDT Wed Apr 18 2018

Latest upper air analysis shows the low from yesterday continuing to
move east.  Following the low is a ridge.  At the surface northwest
winds were gusty.  The strongest winds had occurred during the late
morning into the afternoon, with a peak gust of 57 MPH occurring at
Hill City.

Northwest winds will continue to decline during the rest of the
afternoon as the low level jet on the backside of the upper level
low continues to move east out of the forecast area.

Tonight the northwest winds will become light during the evening
then turn to the southeast as a surface ridge moves through.  Lows
will be cooler than last night due to the very light winds.

Wednesday the southwest winds will increase west of Highway 27,
beginning in the late morning as the low level jet strengthens ahead
of the approaching storm system that will bring much needed rainfall
to the forecast area.  Relative humidity values will be 15-20%
during the afternoon west of a Burlington to Tribune line.  This
will lead to elevated fire conditions when combined with the wind
gusts of 35 MPH.

.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 00Z TAFS through 00Z Thursday evening)
Issued at 540 PM MDT Wed Apr 18 2018

VFR conditions are anticipated at both KGLD and KMCK terminals
through the TAF period, with clear skies forecast overnight.
Northwest winds will decrease this evening, becoming light as they
shift eastward overnight. East/southeast winds increase at KGLD
midday on Thursday to 15 to 20 knots and to 15 knots at KMCK.




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