Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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000
FXUS63 KEAX 240459
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1159 PM CDT Thu Oct 23 2014

.DISCUSSION...
Issued at 303 PM CDT THU OCT 23 2014

The main challenge for tonight is the potential for dense fog
tonight or whether the lower stratus will redevelop. The boundary
layer is very moist both from recent rainfall but more so from moist
advection into the area. This is leading guidance depicting high
probabilities for fog development. The 23/15Z SREF shows
probabilities of seeing less than a mile visibility around 75%. But
there is an equal probability of low stratus. Soundings suggest that
we don`t fully decouple and the result would be low stratus with
more minor fog development. For now, have added areas of fog to
northern/northeastern MO and patchy fog for the rest of the forecast
area. Have also increased cloud cover for the overnight period to
get some mention of clouds but not certain on when/if or even where
any stratus may redevelop have at this point have not gone more than
about 50% sky cover over the forecast area after the current stratus
either moves away or breaks up.

Otherwise, the weather for the weekend looks to be calm and warm for
this time of year. For Friday, highs near 80 seem likely given the
very warm air aloft. However, if cloud cover hangs on later than
expected, temperatures may not rebound as high as forecast. Clouds
seem more likely to linger over the northeastern quadrant of the
forecast area so temperatures closer to 70 look more likely in the
Kirksville area. A weak front may move into/through the area on
Saturday and knock a few degrees off temperatures compared to
Friday. This should be short-lived through as winds again return from
the south and allow temperatures to climb to or above 80 degrees.
This around 15 degrees above normal for this time of year so very
warm for late October.

Our next good chance for rain looks to be Monday and Monday night. A
progressive shortwave trough will track across the Central Plains
and into the Midwest with its associated front trailing through our
region. This should lead to showers and a storms during the day
Monday with thunderstorms diminishing Monday night as instability
wanes. The precipitation should move of the area by Tuesday, though
the GEM is the slowest with the trough and keeps a fair amount of
rain in the area through the day. Have side more with the GFS and
ECMWF, which have been handling the recent upper waves more
consistently, and trimmed back POPs for Tuesday to just the far
eastern zones. For Wednesday and Thursday, the upper ridge will
rebuild over the west with northwesterly flow regime over the Plains
and Missouri Valley. This looks to keep temperatures closer to
seasonal normals with dry conditions expected.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1159 PM CDT THU OCT 23 2014

Very tricky TAF forecast during the first 10 hours of the TAF period
as fog will be a player during this timeframe. Currently the TAF
sites have vsbys ranging from 2SM-4SM. These vsbys will either hold
steady or perhaps even improve with a bkn high cirrus deck moving
over the terminals. Overnight, this cirrus deck may thin and fog may
become more dense. If this scenario were to come to fruition, vsby
would drop to 1/4SM-1SM and as such have added a tempo group for
those potential conds mainly btn 10Z-14Z. It is during this time
frame model guidance and soundings are also hinting at a IFR stratus
deck and have included that in the TEMPO grp as well. But, if the
high clouds do hold over the terminals all night vsbys will remain
MVFR even VFR is conds improve. Fog is expected to hold over the
terminals btn 14Z-15Z when vsbys will lift to P6SM and cigs will sct
btn 2-3kft. Expect skies to clear tonight and that may set the stage
for an early onset of fog tomorrow night at fog prone STJ where vsbys
will decrease in a hurry. Winds thru mid morning will be light out of
the south before veering to the SSW an increasing to around 10kts.
Winds will again diminish tomorrow night to around 5kts which will
also aid in potential fog development tomorrow night.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...DENSE FOG ADVISORY until 9 AM CDT Friday FOR MOZ003>008-013>017-
     021>025-030>032.

&&

$$

DISCUSSION...CDB
AVIATION...73






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