Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 201817

Area Forecast Discussion
National Weather Service Goodland KS
1117 AM MST Fri Jan 20 2017

Issued at 1117 AM MST Fri Jan 20 2017

The remainder of the dense fog advisory has expired.

UPDATE Issued at 1010 AM MST Fri Jan 20 2017

updated forecast to trim off additional areas of the dense fog
advisory where visibilities have improved.

UPDATE Issued at 505 AM MST Fri Jan 20 2017

After taking another look at wet-bulb zero heights and snowfall
probabilities, decided to extend the mention of snow into the
early afternoon. With temperatures warming into the low 40s, the
snow should change to rain by mid afternoon. However if the cloud
cover keeps temperatures a few degrees cooler than forecast this
may not happen. Am not expecting more than a few tenths of an inch
of snowfall in the afternoon before changing to rain.


.SHORT TERM...(Today and tonight)
Issued at 217 AM MST Fri Jan 20 2017

Latest satellite and upper air analysis show a short wave ridge over
the Tri-State Area with another short wave trough approaching from
the west.  Between the two features was a band of snow, with some
moderate to heavy snow reported in the mountains.  At the surface
the trough was near the CO/KS border.  Along and east of the trough
visibilities ranged from a quarter mile to unrestricted.

Today the fog will follow a similar pattern to yesterday of
dissipating by late morning.  Some locations will have a glaze of
ice due to the freezing fog.  The approaching snowfall may cause
visibilities along the CO/KS border to improve sooner than forecast.

Meanwhile expect the band of snowfall to move into the area before
sunrise following a band of frontogenesis. The band of
frontogenesis will move north across the area this morning. As
the day progresses the upper level short wave trough will deepen
over the Tri-State Area. As it deepens WAA and speed convergence
on the west side of the trough will cause lift to increase.
Theta-e lapse rates will fall to around zero across the forecast
area, so there could be some convective driven precipitation in
the afternoon. The higher chances for precipitation will be in the
afternoon, moving in from the west.

Based on wet-bulb zero heights, the precipitation may remain as all
snow into the afternoon.  However, am thinking the early afternoon
temperatures of around 40 degrees should cause the snow to change to
rain.  During the afternoon the higher precipitation amounts are
expected, so if the precipitation does not change over to rain, some
small accumulations of snow can be expected.  Am not anticipating
any freezing rain due to the temperatures quickly warming above the
freezing point.

This evening precipitation chances will decline as the now closed
low moves northeast and the WAA and speed convergence shift out of
the Tri-State Area.  Any lingering precipitation will be northeast
of the Tri-State Area by midnight.

The surface trough will be pushed east of the Tri-State Area this
evening as the closed low lifts northeast.  Due to the surface
trough east of the area, am not expecting any fog to develop during
the night.

.LONG TERM...(Saturday through Thursday)
Issued at 212 AM MST Fri Jan 20 2017

Saturday and Sunday the weather will be dry.  A short wave ridge
will move through Saturday followed by another closed low in the
afternoon.  Some lift from WAA will round the closed low, but will
remain just south of the Tri-State Area Saturday night.  A weak cold
front will move through Saturday night.  Another ridge will begin to
build in from the west Sunday.  The incoming ridge will help negate
any cooling from the cold front causing highs to be similar to
Saturday.  Sunday afternoon northwest winds will be breezy as a weak
low level jet mixes down to the ground.

The main concern in the extended period continues to be an area of
low pressure that is set to develop on Monday, moving out of the
central Rockies and into the central High Plains on Tuesday. There
seems to be good agreement between the global models with regards to
the track; however, the agreement is not as strong as in previous
runs. The trend has been to a more northerly track, keeping the
primary impacts mainly north of Interstate 70. Precipitation will
begin making its way into the northernmost portions of the CWA
around or just after midnight on Monday with slgt chc PoPs becoming
chc PoPs after sunrise. Ptype will be snow at first with a brief
transition to a rain/snow mix or all rain during the early afternoon
before changing back to snow. At this time, the track is not
favorable for large amounts of accumulating snowfall as the center
of the low is expected to traverse our northernmost counties and QPF
is relatively low for our area. The best chances for accumulating
snow, barring any shift in the track, will be northern Yuma County
and the southwest Nebraska counties. The system will move out of the
area by the middle of Wednesday morning.

The remainder of the week will remain dry as high pressure builds
into the western States with a deep trough developing in the eastern
portion of the country. Below average temperatures on Tuesday and
Wednesday will begin to moderate and approach average values as we
head into next weekend.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1027 AM MST Fri Jan 20 2017

GLD will start out VFR and transition to MVFR due to lower
ceilings as light rain spreads across the area and continues
through about 03Z. VFR conditions are expected to return after 03Z
with skies clearing out after 14Z on Saturday.

MCK will start out IFR due to low ceilings with LIFR possible
intermittently through 20Z. After 20Z...isolated rain showers are
possible along with VFR conditions. Skies will be clearing after




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