Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 141722

1222 PM CDT Mon Apr 14 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 417 AM CDT MON APR 14 2014

Early Monday morning, the Sunday cold front had surged well into
Texas with strong cold advection across the region. 3 AM
temperatures were in the mid 30s across the local area and only
slowly falling, but still expect near-freezing or sub-freezing
temperatures in much of the area this morning. Winds remained strong
with gusts up to 40 mph ongoing through the overnight hours with a
fairly strong pressure gradient in place and a strong northerly low
level jet across the area. Aloft, while the initial strong short
wave passed through on Sunday, a second strong wave was moving out
of southeast Colorado this morning. A broad area of moderate to
strong forcing aloft was overspreading Kansas in advance of this
trough, interacting with weak to moderate frontogenesis extending
from SW into NE Kansas. This has resulted in widespread light snow
in western and central Kansas, with embedded bands of at least
moderate snow coincident with strongest areas of frontogenesis. This
setup will shift east across the area this morning with the maximum
forcing expected prior to 8 AM while a second area of weaker forcing
will move over the area through noon. While light snow is possible
across the whole forecast area through 8 AM, the best chances are
south of a Minneapolis to Manhattan to Holton line. After 8 AM, snow
should be limited to areas near/south of I-70 and moreso south of
the turnpike. Light accumulation is possible, but will probably be
quite dependent on snowfall rate as any light rates will melt
quickly given fairly warm ground temps. The best chance for
accumulation more than a dusting seems to be in one area from near
Abilene through Junction City, with another favored area perhaps
from Emporia into the Lawrence area. All-in-all, other than briefly
reduced visibility and some slick bridges/overpasses, expect this to
be a low impact type of snowfall.

Winds will gradually decrease today but will gust to 30+ mph for
much of the day. High temperatures will struggle into the lower 40s
as clouds begin to clear late in the day, hopefully in time for some
warming sunshine. There is some indication of another small area of
clouds around 5000 feet AGL moving across the forecast area from
this evening into the early morning hours, clearing the area by
around 6 AM. So, while high pressure and light winds are expected
tonight after a rather cold day, have not gone as cold with low
temperatures as if it were totally cloud free. Regardless, lows are
forecast to be in the 23 to 27 range, plenty cold to damage
cold-sensitive vegetation, and the freeze warning is more than
warranted tonight.

.LONG TERM...(Tuesday through Sunday)
Issued at 417 AM CDT MON APR 14 2014

Tuesday through Sunday ...

By Tuesday, the mid-level trough that has brought active weather to
the region this past weekend will have progressed further east
toward the Ohio River Valley, with a transition toward a more zonal
mid-level flow expected by mid week. Models show surface high
pressure situated just south of the area by Tuesday morning, but it
looks to be shunted further toward the southeast through the day as
the flattening mid-level flow helps to push an area of low pressure
over the northern Rockies southward into the central High Plains.
With this advancing area of low pressure, the pressure gradient
looks to tighten over north central Kansas by Tuesday afternoon and
continue to develop eastward across the entire outlook area by
Tuesday evening. With this surface pattern, winds will prevail out
of the southwest and gust upwards of 25 to 30 mph across north
central Kansas. This breezy southerly flow will result in
temperatures quickly rebounding into the middle 50s to low 60s.
Additionally, conditions look to be fairly dry on Tuesday with
dewpoints only reaching into the 20s, resulting in RH values
possibly dropping into the low to mid 20 percent range across north
central Kansas. These dry conditions combined with the gusty winds
may result in very high fire danger concerns for north central
Kansas Tuesday afternoon. The tight pressure gradient should remain
in place over the region Tuesday night, keeping overnight low
temperatures warmer in the upper 30s/low 40s, and through much of the
day on Wednesday. In fact, could see wind gusts reach upwards of 30
to 40mph through the day. These strong southerly winds will boost
temperatures up further for Wednesday with highs reaching into the
mid/upper 60s. Depending upon how much green-up we`ll get over the
next few days from this weekend`s rain, Wednesday has the potential
to have high fire weather concerns as well.

On Wednesday, a mid-level trough over the northern Rockies will
deepen southward across the High Plains, helping to push a cold
front southward through the forecast area late Wednesday afternoon
through Thursday morning. While the models are coming into better
agreement with the mid-level pattern of this system, there are still
some minor discrepancies with (a) the strength of the deepening
trough and how far south it digs into the Central Plains, (b) how
quickly the front will track through the area, and (c) the exact
start and end time of precipitation chances. The NAM/GEM bring
moisture in sooner to north central Kansas while the GFS/ECMWF are a
bit slower to saturate behind the front. Trended more toward the
GFS/ECMWF and have PoPs gradually increasing Wednesday night into
Thursday. There`s fairly good agreement in having deeper saturation
in place for much of Thursday and Thursday night, so have continued
to trend upward with PoPs during that period. There may be some
light precipitation lingering across far eastern Kansas Friday
morning before exiting east of the area by late morning/early
afternoon. With colder air surging into the region behind this
system, the potential for wintry precipitation once again becomes a
concern. Temperatures have been trending a bit cooler for early
Thursday morning behind the front across far north central Kansas
with lows possibly dropping into the middle 30s, so have added a
mention of rain/snow mix for that area. By Friday morning, lows may
range from the low 30s to upper 30s from northwest to southeast, so
have continued to mention of rain/snow mix and will need to monitor
the potential for precipitation to switch entirely over to snow
across far north central Kansas.

Surface high pressure will move into the Central Plains on Friday
behind this system with dry conditions Friday afternoon through
Saturday. Models are showing a southern wave trying to merge with
the northern mid-level flow Saturday night into Sunday, however
there is still a great deal of uncertainty with this wave pattern
and the potential for any precipitation across the area, so have
only slight to low-end chance PoPs in for that period.


.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1221 PM CDT MON APR 14 2014

Little change to VFR forecast. Winds should die off quickly around
0Z with surface high building in and be quite light through at
least 15Z, with very light SW winds developing around then.


FREEZE WARNING from 11 PM this evening to 9 AM CDT Tuesday FOR



SHORT TERM...Barjenbruch
LONG TERM...Hennecke
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