Area Forecast Discussion
Issued by NWS Topeka, KS

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895
FXUS63 KTOP 202318
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
618 PM CDT FRI MAY 20 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Saturday)
Issued at 322 PM CDT FRI MAY 20 2016

Center of upper low was into north central Missouri early this
afternoon with high clouds clearing. Lee trough under southwest
upper flow keeping southerly low-level flow in place but gradient
remains weak. Lower levels remain moist with some peaks of sun
mixing in but 19Z dewpoint depressions remain generally below 10F.

Weak lower level flow remains in place into Saturday as mid/upper
ridge axis builds east into the Central Plains. A more easterly flow
may bring dome drier air into eastern areas overnight for some
clearing to continue but weak isentropic lift should combine with
deeper moisture remaining for a cloudier night and day Saturday.
Both the lift and instability look rather meager through tonight,
with somewhat better ingredients for precip developing in the midday
hours of Saturday as the mid level ridge comes east. Will keep
precip mention small in far western areas late tonight and in mainly
southwestern areas Saturday, with thunder chances rather small but
not zero. Will continue with some fog mention in northeastern
locations overnight with more clearing and lighter winds
anticipated.

.LONG TERM...(Saturday Night through Friday)
Issued at 322 PM CDT FRI MAY 20 2016

Models continue to show a low level warm air advection pattern
with decent moisture advection Saturday night and Sunday
morning, so have continued with a slight chance POP since some
but not all solutions want to develop some elevated storms. Deep
layer shear is progged to weaken as the upper ridge axis moves
across the central plains, so chances for strong or severe storms
appears to be pretty small.

The next chance for precip continues to be late Sunday night and
Monday. Models have shown good consistency with storms developing
out west Sunday afternoon and moving east into the forecast area
by Monday morning. Once again, 0-6KM shear is progged to be fairly
weak through the early morning Monday and begins to increase once
the precip is expected to already be moving across the area.
Therefore organized severe weather again looks to be limited. The
main uncertainty with Monday is whether morning precip clears out
and the airmass recovers by the afternoon in which the GFS
develops new convection along the surface trough. The better
forcing is expected to be lifting north of the area by Monday
afternoon. Because of this the better focus for redevelopment may
end up being north of the forecast area and have left POPs in the
chance range for Monday night.

For Tuesday through Friday, models keep a pretty moist airmass
over eastern KS with southwest flow aloft. The GFS is a little
less amplified with the pattern allowing weak vort maximum to move
across the region while the more amplified ECMWF wants to lift a
well defined wave out into the plains late in the forecast
period. Overall shear remains marginal (between 30 and 40 KTS
0-6KM shear) for this time of year, but given the magnitude of
potential instability progged there remains some potential for
strong or severe storms next week. Confidence in trying to time a
specific period is low since the pattern is generally not very
amplified with well defined shortwaves. Nevertheless the forecast
maintains some chances for thunderstorms through the end of the
work week.

The forecast for gradually warming temps continues to look
reasonable as 850 MB temps are progged to warm. With increasing
low level moisture, lows also look to be quite mild. So lows in
the lower and mid 60s with highs in the lower 80s is expected next
week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 614 PM CDT FRI MAY 20 2016

Clouds are beginning to scatter out, which may set up the taf
sites for some haze and or fog tonight. The better chance for
restricted vis will be at TOP/MHK during the predawn hours. If the
clouds do not clear out tonight then the vis might not drop much.
Tomorrow during the day there is a very slight chance for a stray
shower around MHK, but did not mention in the taf due to
uncertainty.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders



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