Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 241046
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
446 AM CST Sat Feb 24 2018

.SHORT TERM...(Today and tonight)
Issued at 445 AM CST Sat Feb 24 2018

As of 10Z Saturday morning the stubborn mid-level trough across
the western CONUS is beginning to eject into the central Plains. A
broad surface high was positioned across the upper midwest,
yielding easterly surface winds. A surface low was centered across
northeast NM with a warm front wrapping southward into central TX
and northward from there into central AR. Isentropic upglide
within the 280-295K layer continues to produce areas to widespread
drizzle across the area. The freezing line was positioned from
near Minneapolis, KS to near Holton, KS. Areas to south have
received predominately non-freezing drizzle. While areas to the
north have remained below freezing with a few hundredths of ice
being reported. Have trimmed the southern extent of the winter
weather advisory by canceling Jefferson, Shawnee, Wabaunsee, and
Lyon counties. As the aforementioned warm front moves northward
through the morning, increasing WAA is expected with most of the
area warming above freezing by midday. Counties in far north
central KS may remain below freezing slightly longer, with
temperatures warming above 32F closer to 21Z. RAP/HRRR/NAM
solutions continue to transition isentropic fields to neutral if
not slightly downglide through the morning. As a result have
decreasing PoPs area wide through the morning and afternoon hours.


The main mid-level trough overspreads the region this afternoon
resulting in steepening mid-level lapse rates. Short term RAP/HRRR
solutions suggest 100-200 J/Kg of MUcape are possible across east-
central KS. Therefore have the potential for a few thunderstorms
mentioned during the early afternoon hours. Otherwise as the mid-
level trough pushes northeast of region and the surface low ejects
into southern MO this evening, ending precipitation chances from
west to east. HRRR/RAP solutions have the entire CWA dry by 00Z
this evening. Westerly surface trajectories will yield weak CAA
across the area, allowing low temperatures to range from the upper
teens to mid 20s Sunday morning.

.LONG TERM...(Sunday through Friday)
Issued at 445 AM CST Sat Feb 24 2018

Next upper wave Sunday still brings with it only some mid and high
cloud, but despite weak advections, highs will still be several
degrees warmer than today. Stronger south to southwest winds develop
for the early week as zonal flow develops over the central Rockies
downstream of an upper trough digging along the California coast.
Warm-air advection Monday is still not strong, though should be
enough for humidity levels to drop into the 20s, with enough wind
for at least Very High fire danger possibilities, mainly in western
areas. Deeper moisture returns in subsequent periods with precip
chances ramping up late Tuesday into Wednesday as the trough swings
into the southern Plains, but model timing differences of this
progression increase notably by this time. Could see enough cold air
come in behind this system for light wintry precip again, but the
modified Pacific airmass moving in should keep any cool-down brief
and weak.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1142 PM CST Fri Feb 23 2018

For the 06Z TAFs, onset of precip has indeed arrived earlier per
previous forecast, but not yet in the form of -FZDZ. Temps are
expected to continue to fall, so have kept freezing precip in the
forecast rather than changed to a prevailing -RA then changeover,
which at the current time could take place in the very short term
forecast especially at KMHK. Expect that by 14-15Z freezing precip
will no longer be a concern like it will be overnight. Still
forecasting LIFR conditions with reasonable confidence as colder
temps and additional moisture settles in over the next several
hours. Improvements come in the last portion of the forecast
period.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 3 PM CST this afternoon for
KSZ008>012-020>024-034>036.

Winter Weather Advisory until 9 AM CST this morning for KSZ037.

&&

$$

SHORT TERM...Baerg
LONG TERM...65
AVIATION...Drake



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