Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 160533

Area Forecast Discussion
National Weather Service Topeka KS
1133 PM CST Thu Feb 15 2018

...Update to aviation forecast discussion...

.DISCUSSION...(This evening through Thursday)
Issued at 243 PM CST Thu Feb 15 2018

As of 21Z Thursday afternoon a mid-level trough axis extended from
the northern Plains into southern California. At the surface a
trough was bisecting the CWA from northeast to southwest. Winds have
shifted to the northwest north of the front with the northern
counties remaining in 50s for afternoon temperatures. Areas south of
the front have seen deeper mixing with heights upwards of 800mb. As
a result temperatures have risen into the upper 60s and lower 70s.
The deeper mixing has also resulted in lower surface RH values in
the lower 20 percents. Westerly winds have also remain sustained
between 10 and 15 MPH with gusts upwards of 20 to 25 MPH. As a
result a Red Flag Warning was issued for the southern tier of
counties through 6 PM. Given the latest temperature and wind trends
the warning may be allowed to expire prior to 6 PM. CAA will
continue to overspread the area through the evening and overnight. A
tightening pressure gradient will yield gusty north winds overnight
with sustained between 15 and 20 MPH with gusts upwards of 25 to 30
MPH. Visible satellite and observations reveals an area of low
stratus across northern NE. Short term guidance suggests this will
overspread the region after sunset. Short term solutions are also
trending towards slightly warmer temperatures overnight with lows in
the upper teens and 20s. That being said, wind chill values are
expected to range from 0 to 10 Friday morning.

Surface high pressure area will overspread the region throughout the
day Friday, decreasing cloud cover and reducing winds to 5-10 MPH.
High temperatures are progged to reach the mid to upper 30s. A
secondary mid level trough and associated surface front will
traverse the CWA Saturday. Most if not all precipitation looks to
remain south of the CWA as available moisture will remain limited
across the area. Fire weather concerns increase behind the front as
northwest winds increase to 15-20 MPH with gusts to 25 MPH. Relative
humidity values are progged to reach the low to mid 20 percents
Saturday afternoon as well. Southerly surface returns to the area
Sunday ahead of the next cold front. High temperatures are progged
to reach the 60s. Fire weather concerns may arise Sunday afternoon
as well, although the worst conditions may stay west of the CWA
where deeper mixing heights are expected. Model solutions continue
to remain in decent agreement regarding the evolution of the western
mid-level trough early next week. All model solutions continue to
generate a few hundred joules of MLcape (400-800 j/kg) ahead of the
cold front Monday. Therefore, continue with the mention of
thunderstorms throughout the day Monday. Maintain a chance for rain
and/or snow Monday into Tuesday as the main mid-level trough ejects
across the northern Plains. Otherwise, much cooler temperatures
arrive Tuesday morning with lows ranging from the mid teens to near
30. Temperatures will begin to moderate Wednesday with highs
returning to the 30s and 40s.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1131 PM CST Thu Feb 15 2018

Lowered cigs for the next few hours just below 2000agl but should
break up toward sunrise. Added some vcsh given some elevated
echoes near the terminals also. Wind forecast remains similar and
diminishes into tomorrow.




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