Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 201133 AAA

633 AM CDT Mon Oct 20 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 322 AM CDT MON OCT 20 2014

Water vapor at 07z shows the most recent northwest flow shortwave
trough extending from the upper MS valley southwestward into the
central plains with good drying within subsidence region aloft
overspreading the county warning area (cwa) with clear skies in all
but the far southeast corner of the cwa. At the same time...surface
boundary is slowly working southeastward across the cwa with only
weak mixing along and ahead of it. This could lead to a brief window
of opportunity for patchy ground fog to form through sunrise across
portions of northeast and east central...although it is not expected
to be significant enough to warrant inserting into the forecast at
this time. Otherwise sunny skies and north to northeast winds
generally under 10 mph will be the rule. Although mixing will not be
deep...thermal fields across the cwa through 850 mb will be slightly
warmer than yesterday at peak expect highs to be as
warm or even slightly warmer than yesterday. Expecting highs to
range from near 71 in the Hiawatha vicinity to the middle 70s in
areas from Minneapolis to Garnett. With clear skies and light winds
tonight...cannot rule out some patchy ground fog in the favored
areas as temperatures cool into the 40s.

.LONG TERM...(Tuesday through Sunday)
Issued at 322 AM CDT MON OCT 20 2014

An upper level trough will move into the western US on Tuesday, then
move east across the plains Wednesday night and early Thursday.

The mild weather will continue on Tuesday as an upper level ridge
moves east across the plains. Highs will reach the lower to mid 70s.

Southerly winds will increase Tuesday night and begin to advect
deeper moisture northward across the plains. The upper trough will
move into the northern and central high plains by late Wednesday
afternoon. A surface cold front will move into western KS Wednesday
afternoon and move east across the state during the night. As the upper
trough moves east into the central plains, stronger ascent ahead of
the H5 trough along with surface convergence ahead of the
approaching cold front will cause showers and isolated thunderstorms
to develop across the western counties of the CWA late Wednesday
afternoon and spread east across the CWA during the night. Highs on
Wednesday will reach the lower to mid 70s with increasing clouds.

As the H5 trough shifts east into the upper Midwest and mid MS river
valley by Thursday afternoon, the showers will end from west to east
across the CWA during the morning hours of Thursday. Skies will
begin to clear during the afternoon hours of Thursday. Thursday will
be the coolest day of the week with highs in the mid to upper 60s.

Expect mild temperatures and dry conditions by the end of the week
and into the weekend as an upper level ridge builds east across the
central and southern plains. Highs will be in the 70s with lows in
the upper 40s to mid 50s.


.AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning)
Issued at 623 AM CDT MON OCT 20 2014

IFR/LIFR vsbys in fog will become vfr by 14z with light/calm winds
becoming north/northeasterly but at speeds less than 9 kts.
Winds will veer more easterly 00Z/21 but at speeds less than 5 kts.
Some potential for patchy fog again between 09z-12z/21...although
confidence remains too low this far out to insert into terminal fcsts
at this time.




LONG TERM...Gargan
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