Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 290530

Area Forecast Discussion
National Weather Service Topeka KS
1130 PM CST Fri Feb 28 2020

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Saturday)
Issued at 347 PM CST Fri Feb 28 2020

Another weak shortwave within the upper level northerly flow has
brought scattered clouds and possibly a few sprinkles to far
northeast Kansas this afternoon, but otherwise skies are mostly
sunny across the region. Ridging will continue to build overnight
and into tomorrow, with skies clearing and winds subsiding
overnight. With clear skies, light winds, and some lingering surface
moisture, can`t completely rule out some patchy river valley fog
towards sunrise tomorrow morning, but this is a lower probability

Tomorrow, warming 850-700 mb temperatures and deep boundary layer
mixing will enable temperatures to warm into the upper 60s. Highs
could reach the low 70s if mixing is slightly greater than
forecast, or moisture advection is slightly less than forecast.
With lee troughing developing towards Colorado and western Kansas,
a tight pressure gradient will form across central and eastern
Kansas, resulting in some gusty southerly winds. (See Fire Weather
section for more details.)

.LONG TERM...(Saturday night through Friday)
Issued at 347 PM CST Fri Feb 28 2020

Warm temperatures will continue Sunday ahead of an approaching cold
front, pushed southward by a strong upper trough near the US/Canada
border. This front will move into north-central Kansas during the
afternoon and evening, with a shift from southerly to northerly
winds as it passes. Even behind the front, deeper mixing will allow
temperatures to reach the 60s, as the colder air lags to the north.
The front will continue to pass through the area Sunday evening and
overnight, with cooler temperatures slowly filtering in. By Monday,
a weak shortwave from within the deep Southwest US trough will move
eastward, with a weak surface low developing and lifting to the
northeast along the front. Some light rain and/or snow is possible
north of this low along an area of mid-level frontogenesis, but
overall precipitation chances have trended lower on Monday as the
front should make a farther push south and east.

Tuesday and Wednesday, the main southwest US trough will lift
northeast into the Southern Plains. There are still differences
between various model solutions, but overall trends have been for a
farther south track of the main trough. While still uncertain, if
this occurred it would allow for most of the precipitation to remain
well to the south, leaving northeast Kansas mainly dry. After that
system passes, ridging should once again begin to build in for the
end of the work week, with dry and quiet conditions looking likely
Thursday and Friday.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1123 PM CST Fri Feb 28 2020

A VFR forecast continues through the period. Winds with strong
southerly flow increase by late morning and remain gusty through
the afternoon. Do expect that winds begin to relax into the
evening, but a little uncertain in how much sustained winds calm
into the end of the period. The thinking right now is that LLWS
conditions may be supported with a strong LLJ aloft overspreading
the area. But the actual strength of those winds aloft are
somewhat lower confidence at this time when compared to the
surface wind speeds. Therefore, have decided to hold off on
mentioning LLWS in the TAF forecast.


Issued at 347 PM CST Fri Feb 28 2020

Deep boundary layer mixing will lead to very high fire weather
conditions tomorrow afternoon across the entire area. Relative
humidity will fall to around 25 percent across the Flint Hills and
north-central Kansas, and to around 30 percent for northeast Kansas.
Southerly winds are expected to increase to 15-20 mph area wide
during the afternoon, with higher gusts of around 25 mph. Land
managers report heavy fuel loads, which despite higher soil moisture
are still dry with the spring green-up yet to take place. As a
result, any fires could grow rapidly, especially given the forecast
weather conditions.




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