Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 122340
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
540 PM CST Tue Dec 12 2017

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday)
Issued at 303 PM CST Tue Dec 12 2017

The overall pattern shows a persistent mid-level ridge located over
the western US, with a deep trough over the Great Lakes region. Over
northeast Kansas, northwest flow continues across the area while at
the surface, a surface boundary approaches the area later this
evening from the northwest.  Dry conditions will prevent any
precipitation chances with this passage.  A cloudless sky tonight
will aid low temperatures dropping near freezing.

Winds shift from the northwest behind this boundary and increase
into the late morning and early afternoon.  Sustained winds of 20-25
mph are expected, with gusts up to 35-40 mph through mid-afternoon.
Main mid-level shortwave moves across the area Wednesday afternoon,
but all the best moisture remains well north and east of the area
keeping another dry day forecast.  Highs wil be above normal
Wednesday reaching into the upper 50s near central Kansas, towards
the low 50s in far northeast Kansas.  With minimum RH values in the
afternoon near 30 percent, elevated fire danger is expected across
the area. See the fire weather discussion for more details.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 303 PM CST Tue Dec 12 2017

The surface gradient begins to relax by Wednesday night decreasing
winds.  Ahead of the next shortwave to impact the area, clouds move
into the area but do not do much to moderate temperatures overnight
with lows reaching into the upper 20s early Thursday morning.  The
clouds hold on through the day and the first small chance for
precipitation occurs for mainly areas north of Interstate-70. During
the afternoon light rain would occur, with the possibility of a
changeover to snow with any lingering precipitation into the night.
For now, no accumulations and little impacts are expected.  Some
flurries may continue through the very early morning.

Another small warm-up into Saturday is seen with highs reaching the
mid-50s Saturday afternoon.  Not too much model agreement after this
timeframe as the ECMWF shows a closed upper low merging with a
northern shortwave, possibly allowing for some precipitation over
the area early Sunday, while the GFS keeps conditions dry as the
northern shortwave lags and the bulk of energy from the southern
system  stays south of the area.  For now, have continued with what
was loaded with no PoPs after the Thursday night system, although
this will need to continue to be monitored.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 531 PM CST Tue Dec 12 2017

Expect VFR conditions for the next 24 hours. A westerly low-level
jet will develop around 1500 feet after 6Z. Therefore the low-
level wind shear will be in the 30 to 40 KTS range during the
early morning hours of Wednesday. After 13Z the surface winds will
increase due boundary layer mixing. West-northwest winds will
increase to 15 to 20 KTS with gusts of 25 to 30 KTS during the
late morning and through the afternoon hours of Wednesday.

&&

.FIRE WEATHER...
Issued at 303 PM CST Tue Dec 12 2017

Very high fire danger is expected across most of northeast Kansas
Wednesday afternoon.  Southwest winds veer from the northwest during
the morning hours, persisting from the northwest through the
afternoon.  Sustained wind speeds of 20-25 mph are expected with
gusts up to 40 mph.  Minimum RH values remain near 30 percent in
central and east central Kansas.  Some models are hinting at
slightly warmer temperatures which may act to decrease RH values
slightly in the afternoon.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Heller
LONG TERM...Heller
AVIATION...Gargan
FIRE WEATHER...Heller



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