Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 190532

Area Forecast Discussion
National Weather Service Topeka KS
1132 PM CST Thu Jan 18 2018

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday)
Issued at 215 PM CST Thu Jan 18 2018

An increase in high clouds and continued warming temperatures are
the biggest highlights of the next 24 hours.

Northeast Kansas will find itself under continued broad SSW flow
through the period with H850 temps gradually warming from +7 C
this afternoon to +12 C by midday Friday. The snowpack once again
tempered high temperatures somewhat this afternoon, with most
locations reaching the mid 30s to mid 40s--warmest in southwestern
portions of the area and along a ribbon of nearly bare ground
running from Morris to Jackson counties. The 1.61 um NIR GOES-16
satellite imagery shows the snowpack to the SW of the CWA has eroded
substantially this afternoon, which will aid in boosting highs
tomorrow well into the 40s to near 50.

There remains some concern that the remaining (albeit localized)
snowpack will modulate temperatures more than previously forecast
and have trended down Friday`s highs in the eastern and northern
portions of the CWA. An increase in cirrostratus spilling over the
top of a SW-NE oriented H300 ridge axis NW of the CWA further
increases confidence that temperatures in the north will be on the
cooler side. Southerly winds on Friday do look to increase to 12
to 18 kts as the pressure gradient increases throughout the
region. Combined with increasing BL moisture transport and
dewpoints rising into the 30s, the remaining snowpack should
disappear before the start of the weekend.

.LONG TERM...(Friday night through Thursday)
Issued at 215 PM CST Thu Jan 18 2018

The bulk of the weekend will feature above normal temperatures,
with an extratropical cyclone bringing the chance for
precipitation Sunday and seasonal temps follow to start next

An upper level trough digs across the California early Saturday
and then lifts northeastward through the central U.S. by early
Monday in a negatively-tilted orientation. Lee cyclogenesis takes
place along the Front Range on Saturday as heights begin to fall
with subsequent increasing baroclinicity along a strengthening
warm front over Kansas. The low pulls eastward early Sunday
morning and then lifts northeastward late in the day. As with
previous forecasts, the dry slot looks to punch directly over the
CWA Sunday afternoon. Light drizzle/FZDZ is possible along and
north of the warm front Sunday morning with a slight chance of
thunderstorms along a pre-frontal trough racing eastward over
eastern Kansas. Despite the GFS MLCAPE fields being not as
impressive as earlier runs, have coordinated to maintain thunder
mention for the time being give the favorable synoptic setup.

The trailing deformation zone looks to linger over portions of
northern/NE Kansas through the night Sunday and into Monday. Total
snow amounts look to be on the lighter side, but the slower
departure of the band does lend some amount of uncertainty. A
moderating zonal flow sets in behind this system with temperatures
near average for early next week.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1128 PM CST Thu Jan 18 2018

The main concern through the period is LLWS through dawn this
morning. Maintain LLWS at all sites between through 14Z as a
40-45kt LLJ near 1kft continues. Otherwise southerly winds will
increase by late Friday morning with sustained near 10kts and
gusts upwards of 20kts. Winds look to decrease to near 10kts by




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