National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDDC 301013
AFDDDC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
413 AM CST Sat Nov 30 2013

...Updated Long Term Section...

.SYNOPSIS...
ISSUED AT 1154 PM CST FRI NOV 29 2013

The 00z upper air analysis showed a southern branch of the upper
level jet extending from northern Baja California into west Texas.
This was spreading some scattered cirriform cloudiness into the
southern plains from the southwest. A weaker northern branch of
the upper level westerlies extended across southern Canada into
New England. A weak shortwave trough in the northern branch
extended from southern Canada into the northern plains and was
moving into the upper Midwest tonight. This shortwave was pushing
a surface trough out of the western High Plains across Kansas this
evening.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 235 AM CST SAT NOV 30 2013

The above mentioned shortwave trough will move into the Great
Lakes and Ohio Valley by this evening. This has pushed a weak
surface trough out into western Kansas overnight. The downsloping
winds in the lower levels of the atmosphere have also pushed
warmer air into western Kansas. A weak Pacific cool front should
push into western Kansas today. Other than a shift to light
northerly winds, little impact will be felt with this front. Given
the warmer air in the lower levels, high temperatures this afternoon
should be able to top out in the low 60s in many areas. Central
and south central Kansas will be the cooler spots with highs in
the upper 50s to around 60. Visible satellite imagery shows some
lingering snow cover over parts of southwest Kansas especially
from Johnson and Ulysses to Richfield. Daytime high temperatures
in this area may also struggle to reach 60 degrees.

Light northerly winds will continue tonight as a surface ridge of
high pressure builds southward toward southwest and central
Kansas. Winds could go light and variable underneath the surface
ridge which would help temperatures spike downward toward Sunday
morning. Will go with mid 20s for lows in west central Kansas,
although a few locations could drop even further. Locations around
south central Kansas should bottom out in the low 30s.

.LONG TERM...(Sunday through Friday)
ISSUED AT 409 AM CST SAT NOV 30 2013

The invasion of arctic air by mid week poses the greatest challenge
for the extended period. There is some uncertainty regarding the
speed of the arctic air as it plunges south from the Northwest
Territories/Yukon, but there is no doubt that it will come and that
it will persist for several days. There is support for an extended
period of cold weather in the central United States and the Midwest
through much of December with only brief periods of moderation
between surges of cold air.

Tropical thunderstorms continue to be very active from the eastern
Indian Ocean to the Maritime Continent, and the velocity potential
field has become more organized into a wave one pattern in recent
days. Most of the numerical models do suggest that eastward
propagation of a coherent cluster of thunderstorms toward the
Maritime Continent will occur by 12-13 December, but it is uncertain
how much this will affect the flow in the North American sector.
Relative atmospheric angular momentum has decreased in recent days,
and the relative angular momentum tendency still is negative.
Although the signal is not strong, the atmosphere appears to be best
represented by phase one of the Weickmann/Berry GWO phase space
diagram. Phase one correlates with anticyclonic flow aloft in the
eastern Pacific and cyclonic flow aloft in the western United
States.

Ocean temperatures in the north Pacific continue to be anomalously
warm from around 130W to the dateline with only slightly below
climatological temperatures near the west coast of North America.
There have been anomalously high heights since September in the
northern latitudes between about 130W and 170W, and ridging is
likely to continue in the eastern Pacific. Stratospheric
temperatures have been warming from Europe to east of Greenland, and
this warming may suggest evolution of a blocking anticyclone in the
north Atlantic. The ESRL reforecast model is trending toward
shifting the coldest air around the hemisphere toward eastern Canada
in early December. The persistence of ridging in the eastern Pacific
and intensification of the polar vortex in eastern Canada favors
surface anticyclogenesis in Alaska, the Yukon and the Northwest
Territories and southward progression of successive surges of arctic
air into the United States.

In the shorter term, a strong upper level trough near 170W is
pumping considerable warm air north toward western Alaska, and a
full latitude ridge is likely to evolve near 145W by early next
week. The upper level cyclone evident on satellite imagery over
eastern Alaska will dig into the Pacific Northwest by Monday night,
and frigid arctic air will begin moving into Montana and Wyoming. As
the upper level trough propagates slowly east into the Rockies
Wednesday, the arctic front air will continue to plunge south in the
lee of the Rockies. Monday will be anomalously warm with downslope flow
and temperatures rising well into the 60s in western Kansas. The
GFS carries a stronger trough across North Dakota and Minnesota
Tuesday than the GEM or ECMWF and pushes the arctic boundary into
northern Kansas Tuesday. Confidence in the GFS solution is not
high, but shallow arctic air often moves faster than the numerical
models suggest. Assuming that the ECMWF is too weak with the
trough moving across the northern plains Tuesday, the cold air may
filter into northwest Kansas by noon Tuesday. The boundary likely
will be very slow to progress south during the day Tuesday with
strong mid level flow across the Rockies and downslope flow in the
lee of the mountains. Temperatures once again should rise into the
60s in advance of the boundary. The cold air should plunge south
across all of western Kansas Tuesday night, and temperatures
Wednesday should hold steady or fall during the day. Very cold
temperatures will persist through the weekend. Minor upper level
troughs in the southwest flow over the arctic air mass will
support snow flurries or areas of light snow in the very sharp mid
level baroclinc zone Thursday and Friday, but the potential for
anything significant is low.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1154 PM CST FRI NOV 29 2013

Fairly benign VFR conditions are expected across central and
southwest Kansas through this taf period. Only some scattered high
level cloudiness is expected. Winds should remain at or below 10
knots through the period.


&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  62  28  57  31 /   0   0   0   0
GCK  62  25  57  29 /   0   0   0   0
EHA  62  31  58  33 /   0   0   0   0
LBL  63  27  58  30 /   0   0   0   0
HYS  58  25  55  30 /   0   0   0   0
P28  62  31  57  30 /   0   0   0   0

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...Gerard
SHORT TERM...Gerard
LONG TERM...Ruthi
AVIATION...Gerard