Area Forecast Discussion
Issued by NWS Dodge City, KS
FXUS63 KDDC 220814
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
314 AM CDT Tue Apr 22 2014
...Updated synopsis and short term discussion...
ISSUED AT 313 AM CDT TUE APR 22 2014
The 00z upper air analysis showed shortwave troughs moving into the
Great Lakes region and the Deep South. West of these features, a
shortwave ridge extended from Alberta, Canada into the Four Corners
region. In the lower levels, high pressure was centered over the
central High Plains.
.SHORT TERM...(Today and tonight)
ISSUED AT 313 AM CDT TUE APR 22 2014
Through today, the upper level ridge will continue to move east out
over the Plains states while a strong shortwave trough moves into
the Intermountain west. The surface ridge will move east as well.
Warm air advection will increase in the low to mid levels over the
central High Plains today, along with some increasing low level
moisture. The far southwest portion of Kansas will see the warmest
afternoon high temperatures in the lower 80s while in central Kansas
around Hays, temperatures should manage to climb into the mid to
upper 70s. As surface pressure falls occur int he lee of the Rockies
today, a strong surface pressure gradient will develop across
western Kansas with breezy to windy conditions developing.
The models continue to indicate thunderstorms developing over eastern
Colorado this afternoon. As warm air advection continues to strengthen
in the lower levels, widely scattered elevated storms should continue
to build eastward into western Kansas especially as a low level jet
strengthens overnight. Will continue to show an eastward progression
of the best thunderstorm chances overnight as the low level jet veers
to the northeast overnight. Have brought thunderstorm chances a little
bit farther south than previously indicated. Overnight lows will be
mild...staying in the mid to upper 50s.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 216 PM CDT MON APR 21 2014
Surface pressures will continue to fall along the lee of the
Rockies Tuesday night as an upper level trough approaches the
central Rockies from the west. Warm air advection develops along
the nose of a low level jet near the eastern edge of an elevated
warm layer after 03z. Based on cooler mid level temperatures, warm
air advection and improving moisture around the 850mb level some
overnight thunderstorms still can not be ruled out near and north
of a Garden City to Rush Center line. Will therefore keep a 20
percent chance of convection Tuesday night in this location.
A dryline will cross portions of far western Kansas on Wednesday.
As the dryline shifts east, a cold front will drop south out of
Nebraska into northwest Kansas. Behind this dryline dewpoints are
expected to fall back into the upper 20s/lower 30s which will
result in relative humidities bottoming out around 15 percent by
late day across portions of far western Kansas. At this time
confidence is not high on how far east the dryline will be late
day, however based on the latest model trends it currently appears
that by late day this boundary will be located west of Dodge City.
Given the movement expected from this dryline Wednesday afternoon
and timing of when the lower dewpoints will begin to spread into
portions of far western Kansas it currently appears that relative
humidities will only briefly drop as low as 15 percent for a few
of the far western counties near the Colorado border. At this time
red flag warning criteria will not be reached for 3 hours so will
therefore not be issuing a red flag warning or watch this
East of the dryline Wednesday afternoon 0-6km shear will be
improving to 40kts or greater by 00z Thursday and CAPE values
greater than 1500 j/kg will be possible which continues to support
the chance for severe thunderstorms on Wednesday afternoon/early
Wednesday night. Surface dewpoints are expected to range from the
upper 40s to lower 50s by late day and model soundings suggested
that the cloud bases will be at or above the 700mb level. At this
time large hail and strong winds appears to be the main hazard
from any storm which does develop late day.
Thunderstorms will be likely through at least the first half of
Wednesday night as convection developing along the cold front
surges south/southeast across western and central Kansas. Based on
the low level moisture axis Wednesday night the area more
favorable for overnight convection will be east of highway 283. A
tight surface pressure gradient along with 925mb-850mb winds
behind this front/convection Wednesday night supports gusty north
winds at 25 to near 35 mph for several hours behind this front.
On Thursday a northwest flow aloft along with subsidence will
develop behind the upper level trough as it moves out of Kansas
and into the Mid Mississippi Valley. At the surface a surface
ridge axis will cross western Kansas during the day, and a trough
of low pressure will begin to develop along the lee of the
Rockies. This trough of low pressure will continue to deepen
Thursday night and Friday as an eastern Pacific upper level storm
system moves east into the southwest United States. GFS, ECMWF, and
ensembles today all differing on track and strength of this next
system from Thursday night through Saturday night as it approaches
the central and southern Rockies. As a result confidence is not
high on timing of the weekend frontal passage or precipitation
chances over the weekend period. All the models do support
improving chances for another round of precipitation for most of
western Kansas sometime this weekend. Based on this will stay
close to the latest CRExtendFcst_Init which currently supports
this improving precipitation chances over the weekend period.
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1200 AM CDT TUE APR 22 2014
Surface high pressure centered over the northern and central Plains
tonight will move into the Mississippi valley by Tuesday evening.
At the same time, surface pressure in the lee of the Rockies will
fall sharply during the day. The increasing surface pressure gradient
across western Kansas will bring gusty south winds. Look for light and
variable winds through the early morning hours to increase from the
south by late morning with wind gusts of 25-35 knots likely by Tuesday
afternoon. VFR skies and visibilities will prevail through the period.
.PRELIMINARY POINT TEMPS/POPS...
DDC 80 55 83 47 / 0 10 40 70
GCK 82 56 84 43 / 10 10 50 50
EHA 83 56 84 43 / 10 10 20 20
LBL 83 57 85 47 / 0 10 30 30
HYS 77 55 82 45 / 10 20 50 70
P28 78 54 83 50 / 0 10 40 40
FIRE WEATHER WATCH from Wednesday afternoon through Wednesday
evening FOR KSZ074-075-084-085.