Area Forecast Discussion
Issued by NWS Dodge City, KS
FXUS63 KDDC 230515
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
1215 AM CDT Sat Aug 23 2014
...Updated synopsis and aviation discussion...
ISSUED AT 1211 AM CDT SAT AUG 23 2014
At 00z Saturday a -17c 500mb trough was centered over Idaho with
a 300mb jet streak extending from the base of the this upper
trough north northeast into the central high plains. Further south
near the right exit region of the upper level jet another upper
level disturbance across southwest New Mexico. Just east of this
upper level system a wedge of higher 700mb and 500mb dew points
were observed across west Texas and western Kansas. Scattered
convection which was ongoing across the Texas Panhandle and
southwest Kansas appeared to relate well to the 700mb moisture
axis ahead of the approaching New Mexico upper level system. At the
surface at 00z Saturday a trough extended from northeast New
Mexico into southwest Kansas. A cold front was located from
eastern Colorado into south central Nebraska. 850mb temperatures
varied from 22c at North Platte to 27c at Dodge City to 29c at
Amarillo and +13c 700mb temperatures were reported at Dodge City
and Amarillo at at 00z Saturday.
.SHORT TERM...(This evening through Saturday)
ISSUED AT 352 PM CDT FRI AUG 22 2014
Subtropical high pressure will continue along the Gulf Coast while a
progressive upper level long wave trough gradually progresses toward
the central part of the country by mid week. Temperatures will
remain well above seasonal averages through the weekend with only
brief cooling behind a weak cold front Saturday night and Sunday.
The numerical models are in good agreement in the near term and
appear reasonable, although they have struggled with the position of
the weak surface trough/stationary front extending from southeast
Colorado into northeast Kansas. The biggest challenge for the short
term is anticipating evolution of thunderstorms tonight and timing
the northward progression of the weak front as a modest low level
jet develops this evening.
Very rich mid level moisture covered the central United States this
morning with H7 dewpoints near 5C in the tropical plume extending
from old Mexico to the Central Plains. A vigorous upper level trough
was evident in central New Mexico early this afternoon, and the
upper level trough will progress across western Kansas to central
Nebraska by Saturday morning. An upper level vorticity maximum
evident in eastern Arizona will progress into Kansas Saturday
morning as the vigorous northern stream upper level trough over the
Pacific Northwest drops into the mean long wave trough position. A
subtropical jet streak with H25 winds in excess of 60kts will move
into eastern Colorado early tonight and into western Nebraska
Saturday morning. Upper level divergence in the entrance region of
the jet streak will support large scale upward vertical motion this
evening, especially across eastern Colorado into northwestern
Scattered thunderstorms with little organization developed early
this afternoon across far southwest Kansas, where surface
temperatures near 100 degrees overcame residual CIN on soundings.
Mid level flow in western Kansas was weak, and limited shear with
backing winds in the mid levels is not favorable for development of
rotating updrafts. The potential exists for microbursts with
inverted V soundings through the late afternoon and evening hours.
The better potential for more organized thunderstorms will exist
later this evening in northeast Colorado into northwest Kansas as
shear increases over rich low level moisture north of the surface
boundary. The boundary likely will lift northward slowly this
evening, and the best baroclinic zone likely will extend from
northwest Kansas to south central Nebraska by 06Z. Upward vertical
motion in the entrance region of the jet will support another area
of thunderstorms that will move from eastern Colorado into western
Kansas this evening. Divergence aloft should be sufficient to keep
scattered showers and thunderstorms going well into the night in
western Kansas, and some high based showers may persist until
sunrise. South winds 10 to 15 knots will keep temperatures warm
tonight, and lows in the upper 60s and lower 70s can be expected.
Saturday will be very warm again with H8 temperatures from 25C to
30C during the afternoon hours. Weak upward vertical motion in
advance of the Arizona upper level trough likely will be sufficient
to support development of widely scattered thunderstorms during the
afternoon hours. Instability will be marginal on Saturday with
dewpoints only in the 50s in southwest Kansas, but inverted V
soundings will support the potential for microbursts.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 404 PM CDT FRI AUG 22 2014
Hot temperatures and periodic tstorm chances will continue for the extended
period. On Sunday, a weak front will move across the region, although
temperature advection associated with the front is not that strong.
The net result is continued temperatures in the 90s. A few thunderstorms
may develop towards the afternoon and evening hours along the front.
This front will stall out across the region towards the beginning of
the next business week. The ECMWF does continue the trend of keeping
at least 2/3rds of the CWA in the warm sector, so not confident on
much of a cool down in averaging the area as a whole. Tstorms during
this period will remain isolated/widely scattered. The highest chance
for storms is during the middle portion of next week as a trof with
upper level dynamics moves across the western Kansas. We could also
see the "coolest" temperatures Wednesday/Thursday, but really, temperatures
will be slightly below or near normal. Beyond that, stuck with the allblend
temperatures. The 12Z ECMWF would suggest slightly cooler temperatures
than compared to the official grids to close out the next business week.
This would not last long though, as warm air advection returns ahead
of the next synoptic trof approaching from the northwest.
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1211 AM CDT SAT AUG 23 2014
Scattered convection will gradually taper off through the predawn
hours as the right exit region of an upper level jet lifts north
towards the Nebraska border. 00z NAM BUFR soundings indicating
that ceilings overnight and early Saturday will be between 7000ft
and 15000ft AGL. A trough of low pressure will be located near the
Colorado border during the day on Saturday which will keep the
surface winds southerly across western Kansas. Wind speeds will
increase into the 15 to 20knot range by late morning.
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 94 69 96 / 20 10 20 20
GCK 67 93 67 95 / 10 10 10 20
EHA 66 93 67 94 / 10 10 20 20
LBL 69 95 69 96 / 10 20 20 20
HYS 69 94 68 95 / 20 10 20 30
P28 73 98 70 98 / 10 20 20 10