Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 201124
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
524 AM CST Sat Dec 20 2014
Issued at 355 AM CST SAT DEC 20 2014
Short Range (Saturday through Sunday):
The main story of this period will be the continued cloudy
conditions as well as the continued periods of fog and drizzle.
However, this period will also feature a warming trend.
Model soundings for this morning continue to indicate that the
column remains saturated from near the surface to about 4kft. This
will continue the potential for light drizzle or freezing drizzle
(as temperatures across northern Missouri hover around freezing)
this morning. However, as we go into the afternoon hours this
moisture becomes even shallower this will bring an end to the
drizzle however, stratus will persist over the area. WAA will allow
temperatures to warm today despite cloudy conditions with highs in
the mid 30s to lower 40s. WAA will continue overnight allowing for
deeper moisture to again penetrate the area and allowing for drizzle
and fog to redevelop especially north of I-70. Fog and drizzle will
persist into Sunday morning. However, WAA will increase out ahead of
an approaching cold front Sunday. This will keep drizzle chances
going on Sunday however, fog should dissipate as southerly winds
increase Sunday afternoon. Increasing southerly winds will also
help temperatures warm into the low to mid 40s.
Medium Range (Sunday night through Tuesday night):
Saturday night a upper level trough will push on shore across the
Pacific Northwest. This trough will quickly move into the northern
Plains by Sunday night. This trough will push across the northern
Plains Sunday night dragging a cold front through the Plains. This
front will will approach the area early Monday morning with rain
developing out ahead of it. Rain will affect the area on Monday as
the cold front moves through. The main concern will be with what the
upper level system does on the behind the cold frontal passage. The
00Z EC solution looks similar to the GFS 24 hours ago taking the
upper trough and moving it thru the Upper Midwest Tuesday and into
the western Great Lakes by Tuesday night. This solution would keep
the area dry on Tuesday and Tuesday night. The GFS deepens the
trough as it moves through the area with a closed low developing in
the base over the trough across the local area. This would bring the
chance for very light snow to the area Tuesday into Tuesday night
with minimal accumulations. With models solutions continuing to
differ through this timeframe have continued to opt for the blended
solution with low end chance and slight chance POPs for Tuesday and
Tuesday night. Temperatures will be cold behind the front on Tuesday
with highs in the mid 30s to the lower 40s.
Extended Range (Wednesday through Friday):
Models solutions continue to diverge through this period making for
a low confidence forecast through this period. The models are in
agreement at the beginning of this period with deep trough over the
eastern CONUS and upper level ridging out west. The GFS flattens out
this pattern through the end of the work week with just a weak upper
level trough pushing through the area on Friday with all associated
precipitation remain north of the area where better forcing resides.
The EC on the other hand digs another deep upper level trough into
the Plains on Thursday night bringing a major winter storm to the
area late Thursday night into Friday. Have generally side with the
GFS here as the EC solution appears to be the outlier. Temperatures
through this period will remain near season normals.
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 524 AM CST SAT DEC 20 2014
Cigs/vis have actually improved overnight with MVFR cigs at the
terminals and VFR vsbys. MVFR cigs will persist into the early
afternoon. However, satellite imagery shows an area of clearing
across eastern Kansas that is pushing slowly eastward. This clearing of
low level stratus will push into the terminals btn 18Z-20Z.
Otrw...expect ovc high cirrus through the afternoon and evening.
After midnight light fog will develop at the terminals reducing vsbys
to 4-5SM. Light winds this morning will increase out of the south to
5-10kts by late morning and persist through the pd.