Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
000
FXUS63 KTOP 201728
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1228 PM CDT FRI MAY 20 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 336 AM CDT FRI MAY 20 2016

A compact vorticity maximum embedded within a broader upper trough
was moving across eastern KS early Friday morning per water vapor
imagery. Scattered light rain showers continued to develop in
association with this vort max amidst a moist lower troposphere.
This light rain will gradually shift east along with the focus for
ascent, with the back edge of the early shower activity exiting east
into Missouri by late morning. However, by afternoon, remnant
moisture and an expectation for scattering clouds and some sunshine
may set the stage for additional scattered convectively driven
showers with very weak instability up to 10000 feet. This activity
will be focused in the afternoon in areas where the sun can shine
for a couple of hours, and will decrease sharply by early evening.
Temperatures today should be in the middle to upper 60s across the
area after a warm start and a bit of afternoon sunshine. Skies are
expected to be partly to mostly clear in the evening, and should see
temperatures fall off where those clear skies are found. Clouds will
then increase from southwest to northeast overnight with
temperatures leveling out and perhaps increasing a bit especially in
central KS. There is a slight chance for an elevated shower or storm
to sneak into the HWY 81 corridor near sunrise but most elevated
parcels should be capped so potential is low. Another consideration
is potential for fog to develop given moist near-surface air, light
winds, and areas of clear skies.

.LONG TERM...(Saturday through Thursday)
Issued at 336 AM CDT FRI MAY 20 2016

The mid-term and extended periods of the forecast will be noted by
an increasingly more active weather pattern, during which there will
be several chances for precipitation.

Saturday into Sunday a narrow mid-level ridge will slide eastward
across the central U.S.  At the surface, the CWA will be wedged
between high pressure to the east and low pressure across the High
Plains, resulting in persistent southerly flow.  This southerly flow
will allow for decent warm-air advection and moisture advection
during the weekend, however temperatures will be very dependent upon
the cloud cover and the potential for precipitation. The last few
model runs have been trending toward increased chances for some
scattered precipitation to develop across the forecast area Saturday
and Saturday night due to the increased moisture and the presence of
some isentropic lift. However, there are some model discrepancies
with regards to the exact location of this scattered precipitation,
so have only slight to low-end chance PoPs at this time. Some
elevated instability will be possible, so could see some
thunderstorms develop. Due to this increasing potential for
scattered precipitation and thus increased cloud cover, have dropped
Saturday high temperatures a couple of degrees into the low/mid 70s.

While some scattered precipitation will be possible across north
central KS on Sunday, precipitation chances start increasing by
Sunday night into Monday as the mid-level ridge shifts east of the
area with a strong mid-level trough developing across the western
U.S. This advancing trough will help to push the surface low
pressure eastward toward the area, with a cold front advancing into
central KS overnight into Monday morning. While the better potential
for severe storms will be focused across western Kansas with the
dryline and cold front in place, cannot rule out the potential for a
few strong storms across north central KS as a complex of storms
across western KS may advance into the area Sunday night.

Through the upcoming week, the broad mid-level trough looks to
remain anchored across the western U.S., resulting in persistent
southwesterly flow aloft and the potential for several shortwaves to
track over the area.  This active weather pattern will help to
support the development of several rounds of showers and
thunderstorms throughout the week, however there are still notable
differences in the exact timing and tracking of these various waves
of precipitation.  As a result, have continued with the consensus
blend for PoPs, which paints PoPs in every forecast period but do
anticipate there being breaks in the precipitation throughout the
week.  With the persistent southerly flow through the week
continuing to support decent moisture and warm-air advection, expect
fairly steady conditions with high temperatures generally in the
upper 70s to mid 80s with dewpoint temperatures in the 60s. As a
result, expect sufficient instability throughout the week to support
the development of thunderstorms, with better 0-6km bulk shear
values noted on Tuesday and Thursday so those periods may have the
better potential for strong to severe thunderstorm development.
While there are several uncertainties still with these thunderstorm
chances next week, the important take-away is that there will be the
potential for strong to severe storms.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1221 PM CDT FRI MAY 20 2016

Current observations continue to show a mixture of MVFR and VFR
cigs across the area. KMHK has remained MVFR for the past several
hours, while the Topeka terminals continue to bounce between VFR
and MVFR. For this reason, have prevailing MVFR at MHK and a tempo
group of MVFR at the Topeka terminals through 22Z. The next question
is fog, confidence still remains low in dense fog formation as
mid- level cloud cover may limit radiational cooling. However,
continue MVFR visibilities within the KS River valley at TOP and
MHK in the 09-13Z timeframe.

&&

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

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...Baerg



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.