Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 272141
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
341 PM CST Tue Jan 27 2015
.SHORT TERM...(This Evening through Thursday Night)
Issued at 341 PM CST TUE JAN 27 2015
In the short term, the main story will be temperatures as a surface
low slides eastward across the MO/IA border and a series of two
shortwave troughs push into the Great Lakes region, enhancing
southerly flow tomorrow and then pushing a surface cold front
through by Thursday morning.
High temperatures tomorrow afternoon will reach the upper 60s to
perhaps lower 70s in southwestern portions of the forecast area, as
a result of 850 mb temperatures in the +12 to +15 range and mixing
to nearly that level as south southwesterly low-level winds
increase. Mainly clear skies during much of the day will also
promote heating, and a dry-ish boundary layer should prevent any
afternoon cu development, especially across the western half of the
The cold front will slide through the CWA between 05z-09z Thursday,
resulting in steadily decreasing temperatures during the morning.
Some recovery into the mid 40s is expected as associated cloud cover
shifts eastward during the afternoon, but cold air advection will
still keep highs much cooler than Wednesday`s near record warmth.
Measurable precipitation with this system is expected to remain to
the north and east of the forecast area due to generally low deep
moisture availability, although light drizzle or a few sprinkles
aren`t out of the question for far northeast MO early Thursday
morning where shallow low-level saturation is a bit more prevalent.
.LONG TERM...(Friday through Tuesday)
Issued at 341 PM CST TUE JAN 27 2015
Friday - Friday night...
Shortwave ridging aloft will dampen as it shifts east into the
Southern Plains as an upper system closes off over southwestern U.S.
and northwest Mexico. Surface high from MN through MO will retreat
east as weak warm advection begins to spread east. However, overall
effect on sensible weather is nil and expect to see near seasonal
Saturday - Sunday night...
While the medium range models, especially the ECMWF and GFS, are
converging on a solution which brings an increasing chance for
precipitation over the CWA, snow and how much are less certain. Once
the upper system moves inland it will be better sampled and the
forecast confidence will improve. That being said it appears the
upper low which closes off over AZ will not phase with the northern
stream shortwave trough that sharpens as it dives southeast through
Based on the above scenario would expect to see an initial batch of
warm advection/isentropically induced precipitation spread across
the CWA on Saturday. Inspection of the GFS and lower resolution
ECMWF sounding profiles shows top-down saturation but with an above
freezing near-surface layer. The primary question is whether or not
cold air will be in place prior to the onset of precipitation. With
a southerly boundary layer and no cooling aloft have to lean more
towards rain or rain/snow mix until Saturday night when colder air
arrives with the northern streams attendant cold front. Too early
plus low confidence to consider snow amounts this far out. Do think
better chance for accumulating snow is over northern and eastern
counties of the CWA. Back edge of deformation cloud shield should
harbor all snow and will clear from west to east quickly.
Monday - Tuesday...
Strong subsidence and arrival of arctic airmass allows us to lower
temperatures both days and even then we may be too conservative.
Fast northwest flow could easily hide a weak impulse or two which
could generate light snow by Tuesday....if not earlier. For now will
leave forecast dry with much below average temperatures.
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1129 AM CST TUE JAN 27 2015
VFR conditions are expected to persist through the forecast period.
Winds will gradually turn to the southeast this afternoon and evening
at speeds below 10 kts, then will veer to the south southwest and
increase to 15 kts or greater, with gusts up to 25 kts.