Area Forecast Discussion
Issued by NWS Goodland, KS

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000
FXUS63 KGLD 161141
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
441 AM MST Mon Jan 16 2017

.SHORT TERM...(This morning through Wednesday night)
Issued at 350 AM MST Mon Jan 16 2017

Winter storm continues to impact our CWA with freezing rain ongoing
from the CO border eastwards, and reports of snow further west in
eastern CO. Dual pol melting layer in eastern CO matches well with
obs as proxy on freezing rain/snow line, with Wray and Yuma already
reporting snow west of this. Using max Tw aloft from RAP analysis as
a proxy, warm nose is still in place near the CO border with 3-4C
temps aloft in our eastern CWA. Instability is in place as moderate
showers are leading to pockets of higher freezing rain accumulation
across our east. Another large area of moderate freezing rain over
SW Kansas is also transitioning northward towards our south-
southeast CWA.

Transition to snow is still expected as upper low moves north-
northeast, however there is a window this morning were moderate
freezing rain will continue and warnings were kept in place to
account for this. Transition to snow should continue in eastern CO
and expectation is that both ice and snow amounts will remain below
warning criteria for these western locations, so our remaining
eastern CO counties were downgraded to advisory.

Regarding snow today: A dry slot currently over south central Kansas
may try to move into our eastern CWA as trowal transitions north-
northeast complicating snow amounts. NAM/GFS/RAP keep this east
while ECMWF/SREF have it moving into our east. Deformation band of
snow is expected to develop by late morning over our CWA, but there
is still uncertainty in how quickly this shifts northeast what what
influence the dry slot could have. At the very least moderate snow
accumulations are still possible east of the CO state line. The
timing of the WSW was not changed to account for the potential for
moderate-heavy snow lingering through the afternoon. When the Ice
Storm Warning is replaced we will need to decide if we need a
product to cover the snow for locations in our southeast where dry
slot could have some influence.

Tonight-Wednesday night: Other than a brief period of lift
associated with a second shortwave drier air will support snow
ending this evening. Dry conditions are then expected with warming
temperatures. Another upper low may move into the region by
Wednesday night but models show a dry layer in place limiting
precip chances. Confidence is still low on highs despite
moderating temps aloft due to possible impact of lingering ice and
snow accumulations post winter storm.

.LONG TERM...(Thursday through Sunday)
Issued at 312 AM MST Mon Jan 16 2017

Forecast concern will be the chance of precipitation into Saturday
night with main emphasis on Friday into Friday night. Satellite
showing a progressive/nearly zonal flow over most of the Pacific.
However that flow buckles and become split and more amplified over
the western of half the North America.

Remnants of the southern end of complex upper trough that is
currently moving through the area will be hanging around through the
day on Thursday. The trough is weak plus there is little to no
moisture available for it to work on. So will keep it dry which is
what the forecast builder gave me.

What gets more interesting is the trough that affects the area
Friday and Friday night. Next mean/large scale upper trough is
developing from the eastern Pacific into the western half of the
country. Models differ on the details and are still not in good
agreement. However the models are consistent in developing a
negatively tilted/slightly closed off system just to our west and
then moving it north and east across the area during this period.

Models showing a decent amount of moisture with precipitable water
values near a half inch. The theta-e lapse rates are not negative
but are low positive. The forcing is weak to moderate. Am concerned
that models may be underdoing this system. Considering the
strength and negatively tilted nature of this system and a
favorable storm track, chose to have a low chance of precipitation
over most of the area. This time period will have to be watched
closely.

Models show another system coming in Saturday night on the heals of
the Friday night system. This system looks weaker, a little further
south, and moisture starved. So chose to keep the slight chance for
the far south and southeast portion of the area for Saturday night.

Mid/upper level ridging builds into the area Sunday and will bring
dry conditions with it. Considering the active nature of the flow
and lack of model/ensemble agreement, chose to make little to no
changes to the temperatures the builder gave me. However one thing
to note. Depending on the amount of snow and/or ice still around
from current storm and what the upcoming storm does, high
temperatures may need to be lowered.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 441 AM MST Mon Jan 16 2017

Winter storm continues to bring freezing rain to both KGLD and
KMCK terminals. Transition to snow should occur within the next
few hours, while vis/cigs will decrease this morning. Moderate
snow developing late this morning will result in vis decreasing
further. Track of band of snow today may result in lower
conditionslingering at KMCK towards 00z while conditions at KGLD
may improve by early afternoon. VFR conditions should prevail at
both TAF sites this evening through the end of the TAF period.
Winds have already increased at KGLD and this trend should occur
at KMCK a little later this morning. Gusty north-northwest winds
should also decrease around sunset.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Winter Storm Warning until 7 PM MST /8 PM CST/ this evening for
     KSZ001>003-013-014-027.

     Ice Storm Warning until 11 AM MST /noon CST/ this morning for
     KSZ004-015-016-028-029-041-042.

CO...Winter Weather Advisory until 7 PM MST this evening for
     COZ090>092.

NE...Winter Storm Warning until 7 PM MST /8 PM CST/ this evening for
     NEZ079>081.

&&

$$

SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR


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