Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 161736
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1236 PM CDT Thu Oct 16 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 317 AM CDT THU OCT 16 2014

08Z water vapor shows a low amplitude ridge over the central plains
and upper MS river valley with a shortwave propagating east
northeast across MT. A surface low has developed over western ND in
response to the shortwave with a surface trough extending south
through the southern high plains.

As the shortwave continues to propagate east across the northern
plains, the surface trough/frontal boundary should move southeast
across the central plains. Forecast soundings show the boundary
layer remaining capped ahead of the boundary with only some week
forcing from frontogenesis. Additionally there is quite a bit of dry
air in the mid levels of the atmosphere. Therefore the frontal
passage is likely to remain dry with only some high clouds passing
overhead. Since the mean westerlies and jet stream stay to the north
with little if any meridional component to the synoptic pattern,
models do not show much cold air advection behind the boundary.
Because of this MOS guidance is coming in with highs in the upper
70s to around 80. Forecast soundings mix the boundary layer to
around 900MB. Mixing this to the surface adiabatically suggests
highs in the upper 70s. With some reasonable insolation think upper
70s are probable and have bumped up highs for today in spite of the
wind shift to the northwest this afternoon. If anything think highs
could be a touch warmer due to downslope effects and continued
mixing behind the boundary. Overnight models keep a little bit of a
pressure gradient across the forecast area. So there may be some
mixing through the night helping to disrupted radiational cooling
and keep lows from bottoming out. Think Friday morning lows will be
in the mid to upper 40s. If anything the forecast may be on the warm
side if the boundary layer is able to decouple.

.LONG TERM...(Friday through Wednesday)
Issued at 317 AM CDT THU OCT 16 2014

As phasing/deepening of the upper troughs over the Great Lakes takes
place...a reinforcing push of cooler air will take place across
the county warning area on Friday that will persist into Saturday.
The atmosphere however will remain dry with no significant forcing
so a dry forecast still looks good through Saturday. Highs
temperatures in the 65 to 70 degree range northeast to southwest
across the CWA respectively will then generally only top out in
the lower to middle 60s on Saturday following lows around 40.

Model continue to trend with weaker moisture return and forcing in
association with the next shortwave trough and cold front Sunday
afternoon into early Monday. Have therefore kept Sunday afternoon
dry and limited shower chances to south and east of the Kansas
Turnpike Sunday night before going dry all areas on Monday. Upstream
ridging aloft will then develop eastward across the CWA through mid
week in advance of the next shortwave trough in the Intermountain
West. This will keep the CWA dry through Wednesday with highs
generally in the upper 60s to middle 70s.

&&

.AVIATION...(For the 18Z TAFs through 18Z Friday Afternoon)
Issued at 1232 PM CDT THU OCT 16 2014

VFR conditions expected through the period, with wind shift
primary impacts. Winds slowly shift from southerly to
northwesterly through the evening hours and may become gusty late
in the taf period.

&&

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

$$

SHORT TERM...Wolters
LONG TERM...63
AVIATION...67





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