000
FXUS63 KTOP 130451
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1151 PM CDT Wed Mar 12 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Thursday)
Issued at 337 PM CDT WED MAR 12 2014

Water vapor loop shows a weak shortwave moving across south central
Nebraska at 19Z. Scattered cumulus clouds developed across the CWA
this afternoon and are expected to dissipate toward sunset.

Tonight...High pressure will build into eastern Kansas resulting in
a light west wind overnight. Soundings and time sections show rather
dry air will be in place with clear skies expected through the
night. Lows tonight will cool into the upper 20s to lower 30s.

Thursday a warm west to southwest downslope wind develops across the
area with the thermal gradient from southwest into northeast Kansas
with 850 mb temperatures in the 7C to 10C range across north central
and northeast Kansas. Soundings show a well mixed layer during the
afternoon hours and mixing down from near 850 MB yields highs in
the mid 60s to near 70 with the warmest temperatures toward central
Kansas. Mixing drier air down from near 850 mb will yield afternoon
dew points in the lower to middle 20s. Minimum afternoon relative
humidity will drop below 20 percent for much of the CWA except the
northeast corner where values near 20 percent are expected. Winds
should be less than 20 mph and gusts look to be just under 25 mph so
will need to monitor for possible Red Flag conditions developing.
Very high fire danger is expected across the entire CWA in the
afternoon.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 337 PM CDT WED MAR 12 2014

The combination of the approaching northern and southern stream
shortwave troughs from the west Thursday night will gradually
increase high clouds over the county warning area (cwa). This is
conjunction with good/increased mixing through the night should help
to keep lows temps up into Friday morning ahead of the next front.
Little change was made to the lows in the low to middle 40s. A weak
frontal boundary will move across the cwa on Friday...but begin to
dissipate by later Saturday night. This front will still cool highs
slightly with readings expected to top out in the low to mid 60s as
high clouds thin through the day.

The next shortwave trough will move into the central high plains by
midday Saturday. This will induce leeside cyclogenesis and a return
to only light southerly winds as mid and high clouds gradually
increase again along with a slight chance for showers in the far
east central later in the afternoon. Edged highs up a degree or
two...although llvl wind speeds/mixing and component not as
favorable for stronger warming as previous systems...so will keep
highs in the middle 60s for now.

The main upper trough will pass across the cwa Saturday
night...exiting the area by midday Sunday...but the better forcing
is expected to be mainly south of the cwa and has increased its
expected speed with a faster exit time from the area. Bottom
line...have left pops generally as slight chance Saturday night and
early Sunday with a possible rain/snow mix Sunday morning northeast
as precip chances come to an end. Have removed precip chances for
Sunday afternoon. Kept lows in the 30s Saturday night and highs
Sunday in the 40s.

As the upper flow across the area backs into early next
week...warmer air will surge back east again with highs into the 60s
both Monday and Tuesday before another front and cooler air lower
highs back into the 50s for Wednesday. A quick moving shortwave will
skirt the northeast corner of the area with a slight chance for
rain or snow Monday night...otherwise will keep the remainder of the
extended dry for now.

&&

.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1147 PM CDT WED MAR 12 2014

VFR conditions expected through the taf period. Low level wind
shear may be possible towards the end of the period. As a boundary
approaches the area the low level jet increases to around 5o kt at
2 kft. Will let later shifts evaluate this potential in more
detail.

&&

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

$$

SHORT TERM...53
LONG TERM...63
AVIATION...Sanders