Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 161113
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
613 AM CDT Mon Apr 16 2018

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 321 AM CDT Mon Apr 16 2018

A weather system that has been affecting the area in one way or
another since late last week should *finally* clear NE Kansas this
morning.

An expansive H850 cyclonic flow associated with a negative-tilted
upper tropospheric trough stretched from the eastern Dakotas to
Maine early this morning. A downstream omega block off the Eastern
Seaboard has resulted in the system lingering over the region for
longer than was previously forecast. The end result for northeast
Kansas early this morning has been a persistent stratus deck that
has prevented temperatures from bottoming out as low as first
thought. A few ribbons of clearing are translating down the mid-
Missouri River Valley, but these have been filling in as they work
into eastern Kansas. With recent satellite trends showing this
clearing over western Iowa increasing, it is possible that these
breaks do begin to work into far NE/east central Kansas in the next
few hours.

Nearly all of the short-range guidance has failed to resolve this
stratus shield, with recent runs of the RAP starting to latch onto
the clouds in its BUFR profiles. Using the RAP H850 wind streamline
analysis and current satellite trends, have gradually lessened the
coverage of the stratus along its western and eastern flanks between
now and 14Z and clear the last of the clouds by 17Z--coinciding with
the relaxation of the NNW flow ahead of the H850 ridge. However,
high cirrus spilling over an upstream H500 ridge axis will begin to
overspread the region this afternoon and tonight. CAA wanes with the
passing of the surface ridge early this afternoon, with H850 temps
climbing from -10C to +5C during the course of the day. Surface
temperatures will respond accordingly, rising into the 50s
throughout the CWA. This is still over 10 degrees below normal for
this time of year.

.LONG TERM...(Tuesday through Sunday)
Issued at 321 AM CDT Mon Apr 16 2018

A mid level ridge will be present over eastern Kansas Tuesday
morning then translate eastward as an mid and upper level trough
moves out into the Plains. A surface low is forecast to deepen over
central and northeast Kansas as a 500 mb 100 kt jet moves across
north central and northeast Kansas. A thermal ridge axis will extend
northeast into north central and northeast Kansas where 850 mb temps
will range from 13 to 22 Celsius in the afternoon, which will yield
highs in the mid 60s to upper 70s. Winds should pick up in the
afternoon and overnight Tuesday as the surface low deepens and moves
northeast into iowa by early Wednesday. There may be enough moisture
along the Nebraska border for a slight chance of showers near and
north of Highway 36. A cold front will move across the CWA Tuesday
night with gusty west to northwest winds behind the front. Lows
Wednesday morning will mainly be in the 40s behind the front. On
wednesday cooler temperatures near normal are expected. However
there will be good momentum transfer through the day with stronger
winds aloft owing to increased winds and wind gusts up to 40 mph
through the day. The gradient will weaken by late afternoon and
evening as the surface low moves northeast toward the Great Lakes.
High pressure builds into Kansas Wednesday night and Thursday with
light winds expected along with clear skies good radiational
cooling will allow temperatures to cool into the mid 30s by Thursday
morning.

The next chance for precipitation continues to come at the end of
the week and into the weekend as another upper trough moves out into
the Plains, but taking a more southern track across the central and
southern Plains. Currently will continue with rain as the
predominate precipitation type, although Thursday night could see a
brief rain and snow mix along the Nebraska border. Thermal profiles
from forecast soundings would suggest that precipitation could
mainly be rain Saturday and Sunday. Highs will mainly be in the 50s
and 60s with lows mainly in the 40s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 612 AM CDT Mon Apr 16 2018

A broad swath of MVFR stratus has started showing signs of eroding
in satellite data and should continue to decay throughout the
morning. Ceilings at the TAF sites should scatter out around 14 to
15Z. Light NW winds will become variable this afternoon as high
pressure moves through, becoming ESE at 5 to 10 kts this evening.

&&

.FIRE WEATHER...
Issued at 321 AM CDT Mon Apr 16 2018

Higher relative humidity expected on Tuesday in the 29 to 45 percent
range will relegate any very high fire danger to the far southern
portions of Morris and Lyon counties in the afternoon. The rest of
the are should continue to see high fire danger. On Wednesday drier
air will be in place and in conjunction with gusty northwest winds
up to 40 mph will yield very high fire danger across the entire area
as some dry fuels remain across the area.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Skow
LONG TERM...53
AVIATION...Skow
FIRE WEATHER...53



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