Area Forecast Discussion
Issued by NWS Dodge City, KS
FXUS63 KDDC 182100
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
300 PM CST Wed Dec 18 2013
...Updated synopsis and short term discussion...
ISSUED AT 257 PM CST WED DEC 18 2013
The 12z upper air analysis showed a more zonal 500 millibar wind
flow pattern over the lower 48 states compared to the last few days.
This was a result of a strong shortwave trough exiting New England
and the next big shortwave moving south through western Canada
toward the northwestern states. The airmass over the central plains
is pretty dry except in the upper levels where some high level
moisture was resulting in scattered to broken cirrus clouds. At the
850 millibar level, a very warm airmass was in place over the
central High Plains where temperatures were in the mid teens
Celsius. Very cold air was moving south through southern Canada
where temperatures were in the teens below zero Celsius.
At the surface, a broad trough extended from the northern plains to
along the Kansas/Colorado border and into northeastern New Mexico.
.SHORT TERM...(This evening through Thursday)
ISSUED AT 257 PM CST WED DEC 18 2013
The shortwave over southwest Canada will continue to dig southward
along the west coast through tonight and Thursday. The NAM/GFS/ECMWF
show the shortwave closing off into an upper low along the coast of
southern California Thursday afternoon. At the same time, the
northern portion of the wave is progged to head towards the Dakotas
and Wyoming. A quiet night weather-wise is expected tonight as
scattered to broken high level clouds continue to stream over
western Kansas. A cold front will push south into western Kansas by
Thursday morning and continue to slowly push south out of Kansas
during the day. Initially, the air behind the front will not be that
cold. As a result, we will see at least some diurnal temperature
trend across southwest Kansas with highs only reaching the mid 40s
along I-70 and into the mid and upper 50s along the Oklahoma border.
Have adjusted the amount of cloudiness to hold back on the intrusion
of low level stratus on Thursday. Central Kansas could see low
clouds moving in during the afternoon but areas farther south should
stay partly cloudy through the day.
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 403 AM CST WED DEC 18 2013
A dramatic change to the sensible weather is expected beginning
Thursday, followed by increasing confidence in winter weather
impacts heading into the weekend.
Both the GFS and ECMWF continue to be in agreement on the main
synoptic pattern evolution through the weekend. Another arctic surface
anticyclone will dive into the U.S. Plains Thursday with a cold
front likely moving through western and central Kansas during the
morning and early afternoon on Thursday. Falling afternoon
temperatures and increasing stratus clouds can be expected. The
models indicate the stronger winds won`t be right during frontal
passage but rather later in the evening into the overnight in the
subsident post frontal airmass.
Of probably even more concern will be potential for wintry
precipitation by Saturday evening. The numerical models continue to
show the pattern of a warm front creating potential for isentropic
lift across the southern plains late in the day. A significant
thermal gradient will be in place as a cold pool advances aloft,
enhancing mid level frontogenesis somewhere along the Kansas and
Oklahoma line. The ECMWF and GFS seems to suggest a brief period of
drizzle possible Saturday, but rapidly changing over to snow based
on the thermal top down forecast sounding profiles. Given that the
models already produce convection across eastern Oklahoma, a fair
amount of confidence exists in the pattern being basically
correct. The ECMWF was less aggressive that the GFS is in
determining snow amounts, however taking the least common snow
amounts, a couple of inches are possible from areas near MINNEOLA to
Medicine lodge and perhaps even farther north near Greensburg and
Pratt, depending on where the best frontogenesis occurs. Minor
adjustments to the forecast QPF and snow amounts were added,
focusing on accumulation along the KS/OK line.
Temperatures will likely return to near normal for late December
(highs in the 40s) briefly by Monday. Another Pacific cold front
appears poised to move into the Great Plains after Tuesday.
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1144 AM CST WED DEC 18 2013
VFR conditions will continue through this taf period. Southwest
winds at 10 to 20 knots will continue through this afternoon. The
winds will be gusty at times to around 25-30 knots at Dodge City
this afternoon. Look for winds to become light and variable
tonight before switching around to the north on Thursday morning
as a cold front pushes south across western Kansas.
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 49 18 35 / 0 0 10 10
GCK 29 48 17 35 / 0 0 10 10
EHA 34 58 21 40 / 0 0 10 10
LBL 31 55 20 38 / 0 0 10 10
HYS 30 44 15 30 / 0 0 10 0
P28 39 59 22 35 / 0 0 10 10