Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 052119

Area Forecast Discussion
National Weather Service Topeka KS
319 PM CST Tue Dec 5 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 317 PM CST Tue Dec 5 2017

Upper low continues to deepen across central Ontario, Canada with
gusty and stout downstream flow over the central plains this
afternoon. Northeast Kansas resides between the sfc trough axis
towards the Midwest and the ridge axis over Oklahoma. As the trough
shifts eastward this evening, strong winds wane to around 10 mph
this evening as they veer towards the northwest. Increasing high
clouds spread southward overnight accompanied by an embedded
vorticity max over the high plains. The insulation will hold
overnight lows a few degrees warmer in the upper 20s.

As the upper vort lobe encounters drier air over northeast Kansas,
there is a slight chance for a few sprinkles or flurries on
Wednesday afternoon. Forecast soundings show a shallow moisture
layer around 800 mb with ample lift associated above it. The GFS and
a few of the high resolution guidance solutions are hinting at this
occurring while most guidance remains dry so confidence in any
accumulating precip is on the low end. Forecast highs and wind
speeds are fairly similar to today with readings in the middle 40s
and northwest sustained speeds between 15 and 25 mph. The main
exception is the higher dewpoints ranging in the upper teens to
middle 20s, resulting in higher minimum RH values in the 30 to 40
percent range.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 317 PM CST Tue Dec 5 2017

Little changes made to the extended period as the elongated upper
trough axis holds over Canada, placing our region under dry
northwest flow aloft. A stronger push of colder air arrives Thursday
through Friday morning. 925 mb temps are 8 to 12C below zero Celsius
Thursday afternoon while sfc highs struggle to reach the lower 30s.
Low temps on Thursday and Friday mornings are averaging in the teens
under mostly clear skies and winds under 10 mph. The main upper
trough gradually exits towards the northeast conus while winds back
from the north on Saturday to the southwest on Sunday, increasing
highs between the lower 40s Saturday to the middle 50s on Sunday
afternoon. Next slight chance for precip arrives Monday night with a
quick moving system over the central plains. Predominant precip type
is mostly rain with perhaps a mix of rain and snow towards the
evening hours in far northern Kansas. Details still remain uncertain
on timing even though both the GFS and ECMWF runs are highlighting
the qpf potential.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1121 AM CST Tue Dec 5 2017

VFR prevails at KTOP/KFOE/KMHK with main concern being the
development of LLWS aft 03Z. Stout sfc inversion develops tonight
with a passing upper system increasing winds around 1000 feet
between 30 and 40 kts. Winds at this level also veer towards the
northwest with light southwesterly winds at the sfc.


Issued at 317 PM CST Tue Dec 5 2017

The very dry and seasonal airmass has taken over the region this
afternoon with RH values hovering around 20 percent. Meanwhile high
temperatures are likely reaching their peak around 50 degrees so am
not expecting Rh values to fall any further this afternoon. The
strong westerly winds this afternoon are not as widespread as
previously forecast with most areas in the 10 to 15 mph sustained
range, gusting to 25 mph at times. Towards the higher elevations,
sustained speeds are closer to 20 mph sustained with gusts in excess
of 30 mph. As a whole, the cooler temps are likely playing a role in
the rangeland fire danger index not being in the extreme category,
however widespread very high conditions remain plausible for the
next few hours.




LONG TERM...Prieto
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