Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 152055

Area Forecast Discussion
National Weather Service Topeka KS
355 PM CDT Thu Mar 15 2018

.SHORT TERM...(This evening through Friday)
Issued at 309 PM CDT Thu Mar 15 2018

Red Flag Warnings are in effect through early this evening and
again tomorrow (Friday) as addressed in the Fire Weather section

Strong surface cyclogenesis continues over the central High
Plains. The interaction of the broader, strengthening cyclonic
flow within an eastward/southeastward-arching baroclinic zone is
inducing a zone of frontogenesis over the far northern forecast
area -- toward the Nebraska border. This zone serves as the
northern bound for the deepest boundary layer within which gusty
winds and low relative humidity are creating extreme fire danger.

While the boundary layer undergoes slight decoupling tonight and
surface winds correspondingly back, an influx of poorly modified
Gulf moisture will occur -- aided by a nocturnally strengthening
low-level jet within the cyclone`s warm sector. While more
appreciable boundary-layer moistening is presently confined to
central Texas vicinity and points southward, the substantial
poleward low-level mass flux above the surface should foster
elevated moisture transport into the region. This moisture will
eventually be manifest at the surface via shear-driven and then
diurnally enhanced mixing late tonight into Friday within a narrow
corridor arching eastward/southeastward from a surface cyclone
migrating eastward across northern Kansas. Larger-scale downslope
flow within the southern semicircle of the cyclone will encourage
the eastward and eventual northeastward spread of the diurnally-
enhanced deep boundary layer into portions of northeast Kansas
Friday afternoon. Sufficiently strong low/mid-level flow
overlapping with the boundary layer will result in extreme fire
danger across Friday`s Red Flag Warning area.

As the periphery of steep low-level lapse rates intersects the
corridor of modest return moisture, sufficient buoyancy will exist
for some potential for diurnal storm development, especially as
height falls preceding a migratory mid/upper-level low overspread
the buoyancy. Despite marginal buoyancy, sufficient deep shear
and low-level hodograph curvature may conditional foster
sustained, organized, rotating convection. However, present
indications are that storm motions may quickly displace convection
toward the cool/stable side of the return-moisture corridor upon
development, restricting the residence time of its ingestion of
surface-based effective inflow. As a result, the risk for strong
to perhaps severe storms is non-zero, but is highly conditional,
and will be confined to areas generally north of the Red Flag
Warning area.

.LONG TERM...(Friday night through Thursday)
Issued at 309 PM CDT Thu Mar 15 2018

An influx of continental air behind the departing cyclone will
result in little in the way of impactful weather through much of
the weekend. A surface cyclone accompanying a midlevel speed
maximum is forecast to move across parts of Oklahoma and Kansas
late Sunday into Monday. Surface-based buoyancy associated with
Gulf moisture return should remain south of the region, though
showers and perhaps a few thunderstorms may affect the area.
Strong storms are not expected. An influx of cooler air behind
the latter cyclone may support some potential for light snow
Monday night into Tuesday as another disturbance crosses the
region, before drier conditions become established later in the


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1240 PM CDT Thu Mar 15 2018

VFR conditions are expected through this afternoon and into
tonight. A stratus deck will become established by later tonight,
though ceilings should remain in the VFR category through much of
the overnight hours. However, by early Friday morning, ceilings
are expected to lower to the MVFR category across the TAF sites
with scattered showers and isolated thunderstorms developing and
persisting into the day. Confidence in thunderstorms affecting any
given TAF site is too limited for inclusion in the TAFs at this
time. Gusty southerly winds are expected into this evening, before
diminishing in speed and gradually shifting to the east-
southeast through Friday morning. During the day on Friday, east-
southeast winds are expected to become gusty once again, and will
gradually shift to more southerly during the day. Also, marginal
low-level wind shear conditions will be possible tonight.


Issued at 309 PM CDT Thu Mar 15 2018

A Red Flag Warning remains in effect until 8 PM this evening along and
south of a line from Concordia to Holton, and a Red Flag Warning
will be in effect from 10 AM to 8 PM Friday along and south of a
line from Minneapolis to Ottawa. In both cases, strong winds will
combine with relative humidity around 20-25 percent across the Red
Flag Warning areas. These factors combined with the presence of
very dry fuels warrant the Red Flag Warnings. Of note, a wind
shift from the south to west and then northwest is expected from
Friday afternoon to Friday evening.


Red Flag Warning until 8 PM CDT this evening for KSZ020>024-026-

Red Flag Warning from 10 AM to 8 PM CDT Friday for KSZ034>038-



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