Area Forecast Discussion
Issued by NWS Dodge City, KS

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FXUS63 KDDC 172141

Area Forecast Discussion
National Weather Service Dodge City KS
341 PM CST Sat Feb 17 2018

...Updated Fire Weather Section...

.SHORT TERM...(This evening through Sunday)
Issued at 205 PM CST Sat Feb 17 2018

A vigorous upper level trough that was moving into western
Washington State early this afternoon will move rapidly across the
northern Rockies to eastern Montana by Sunday morning. Pressures
already were beginning to fall in the lee of the Rockies by 19Z,
and little pressure gradient was evident in western Kansas. Gusty
north winds will diminish quickly with loss of momentum transfer
later this afternoon and should become light and variable by early
evening before returning to the south and increasing during the
nighttime hours. The strong jet along the British Columbia will
continue to dig into the western United States tonight and Sunday,
and strong flow perpendicular to the Rockies will result in
deepening of the lee trough. As the initial trough moves across
the Dakotas Sunday, low level flow will veer, and a plume of very
warm air will spread into the central Plains. Low level moisture
in southwest Texas will begin to flow north Sunday morning, and
dewpoints will rise into the 30s in south central and central
Kansas by afternoon. However, most of western Kansas will remain
in the dry, downslope regime with critical or near-critical fire

Temperatures tonight will be mild for this time of the year since
low level winds will provide good mixing by late evening.
Temperatures Sunday will be anomalously warm with highs mostly in
the lower 70s. There will be some increase in cirriform cloudiness
as the plume of high level moisture evident on satellite imagery
from the tropics to the southwestern United States spreads
northeast in response to the digging trough.

.LONG TERM...(Sunday night through Saturday)
Issued at 205 PM CST Sat Feb 17 2018

An active flow regime can be expected with a mean trough in
western North America and a strong upper level ridge from the Gulf
of Mexico across Florida into the western Atlantic. The very deep
cyclone centered northwest of Hudson Bay should weaken slightly
and propagate toward Greenland early next week before redeveloping
back westward by next weekend. There will be a continued stream
of minor upper level troughs digging into the western United
States and subsequently lifting out across the central part of the
country, but the troughs will be so progressive and frequent that
it will be difficult for deep moisture to return to western
Kansas. As such, the potential for beneficial rainfall in western
Kansas is low for most of next week.

A strong stratospheric warming event that developed quickly over
the North Atlantic and the Scandinavian Countries the first week
of February has continued to expand in recent days, and
anomalously warm temperatures in the stratosphere covered much of
the polar region by late this week. There always is uncertainty
about how the troposphere will respond to such events, but it is
likely the high latitude flow will become weaker and more blocky
through late February and early March. The global models are in
reasonably good agreement with building strong upper level ridging
in western Europe with subsequent retrogression of the high
latitude ridge toward Greenland around 1 March and into eastern
Canada the first week of March. The deep Hudson Bay vortex likely
will weaken and retrograde into the western part of the Canadian
Arctic while the main lobe of the polar flow shifts toward Asia.
If the high latitude ridge does retrograde as suggested, an area
of low pressure may develop under the ridge in the Midwest with a
flow of cold air into the central part of the country by mid

A Madden Julian Oscillation in the Pacific Ocean will propagate
through the western hemisphere and reach the western Indian Ocean
by the last week of February. Although the Madden Julian
Oscillation is likely to weaken as it propagates toward the Indian
Ocean, it likely will maintain enough amplitude into early March
to have some effect on mid latitude flow. This evolution favors
troughing in the western United States and at least some chance
for precipitation at times in the central part of the country into
early March. If the blocky high latitude flow evolves as planned
in early March, the potential for beneficial precipitation in the
central Plains may be delayed to around the equinox. As with any
extended period forecast, confidence in details is extremely low.

The strong jet near the British Columbia coast will dig into the
southwestern United States Monday, and a cold front will sag
slowly south across Kansas. Temperatures are a real challenge in
southern Kansas Monday since the front may stall near the Oklahoma
border as cyclogenesis occurs in southeast Colorado. There will
be a sharp gradient along the boundary with temperatures in the
lower 70s south of the front and about 35 degrees colder on the
cold side of the baroclinic zone. The cold front will surge south
Monday night and Tuesday as an upper level trough lifts out across
the central and northern Plains. Low level moisture largely will
be shunted east of southwest Kansas, but there could be some
chance for light rain in south central Kansas Tuesday morning.

Cold high pressure will invade western Kansas as the cold front
surges south Tuesday, and highs likely will be mostly in the 20s
and low 30s Tuesday with some moderation Wednesday and Thursday.
The numerical models differ in synoptic scale details late next
week. The ECMWF and GEM maintain a deeper trough in the
southwestern United States than the GFS, and there are differences
in timing and amplitudes of minor troughs rippling through the
flow. It does appear that there may be another opportunity for
light precipitation in western Kansas Friday, but details are
highly uncertain. Temperatures will be near or slightly above
climatological averages.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1151 AM CST Sat Feb 17 2018

VFR conditions will continue through Sunday. Skies will remain
mostly clear with only a few thin cirrus clouds tonight and
Sunday. Low level north winds 20-30 kts with gusts to near 40 kts
will diminish to 10-15 kts by 21Z and become light and variable
around sunset. Low level south winds will increase during the
night to 15-20 knots with gusts to 25 knots after midnight. A
strong low level jet will produce low level wind shear from 08z
until the low level jet mixes out 15Z-16Z. Low level winds will
increase to 20-30 kts sustained with gusts to near 40 kts by 16Z.

A vigorous upper level trough was moving into southwest Iowa at
17Z, and a surface cold front extended from northwest Missouri to
southwest Oklahoma. Cold air advection behind the front was
supporting downward mixing of strong winds above the surface,
resulting in strong and gusty low level winds. Surface high
pressure will build in western Kansas this afternoon, and winds
will diminish quickly by mid afternoon.

An upper level trough near the British Columbia coast will move
rapidly to eastern Montana by Sunday morning, and pressures will
fall rapidly in the lee of the northern Rockies. Another deep
upper level trough will dig into the Pacific Northwest Sunday, and
a surface cyclone will develop in northeast Colorado Sunday
afternoon. A strong pressure gradient across Kansas will produce
gusty south winds late tonight and Sunday.


Issued at 205 PM CST Sat Feb 17 2018

Low level winds will become south tonight as pressures fall in the
lee of the Rockies and will increase to 25 to 35 mph with gusts to
near 50 mph by late Sunday morning. Critical fire weather is
likely with relative humidities falling to around 15 percent west
of a line from Liberal to Hays. Limited low level moisture return
in south central Kansas Sunday afternoon likely will keep relative
humidity values above the red flag criterion, but extremely dry
fuels and very strong winds will make fires very difficult to
control. In addition, the absence of snow or ice this winter in
much of western Kansas has allowed grasses to stand tall instead
of being matted to the ground. This favors very hot fires that
spread rapidly. The fire weather watch was upgraded to a red flag
warning in the area most likely to experience relative humidities
at or below 15% with a watch farther to the east. The moisture
return can be evaluated later to determine if the warning area
needs to be expanded.


DDC  36  73  44  65 /   0   0   0   0
GCK  34  74  36  58 /   0   0   0   0
EHA  37  75  42  70 /   0   0   0   0
LBL  35  76  46  72 /   0   0   0   0
HYS  34  71  32  42 /   0   0  10   0
P28  34  69  54  73 /   0   0  10  10


Red Flag Warning from 1 PM CST /noon MST/ to 7 PM CST /6 PM MST/
Sunday for KSZ030-043>045-061>063-074>077-084>086.

Fire Weather Watch from Sunday afternoon through Sunday evening
for KSZ031-046-064>066-078>080-087>089.



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