Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 270456

Area Forecast Discussion
National Weather Service Goodland KS
1056 PM MDT Wed Jul 26 2017

Issued at 955 PM MDT Wed Jul 26 2017

Convection over Colorado has been persistent this evening, producing
locally heavy rainfall around Pueblo and Colorado Springs and
areas further southeast. Precipitation still has not reached the
southwest part of our forecast area. Latest guidance indicates
showers and isolated thunderstorms will still be possible tonight,
mainly over Cheyenne County Colorado and Greeley and Wichita
counties in Kansas, but heavy rain potential may remain further
south. Light northeast winds and moisture in low levels will
result in a low stratus deck and patchy fog developing overnight.


.SHORT TERM...(This evening through Thursday)
Issued at 200 PM MDT Wed Jul 26 2017

Cold front has cleared the forecast area and continues to move
south. Thunderstorm chances tonight will be tied to post frontal
upslope into the higher terrain of northeast Colorado, with
perhaps some help aloft from weak shortwave energy rotating
around the ridge. Storms will initiate along the Palmer Divide and
move east-southeast with the mean flow, which is very weak. They
will also be moving into an increasingly moist environment with
precipitable water values of greater than 1.5 inches in western
Kansas. The combination of slow storm motions and anomalous
moisture content may lead to locally heave rainfall. The main
threat will be along and south of Highway 40. Storms will linger
through the overnight and into Thursday morning, gradually
weakening through that time, ending by late Thursday morning.
There might be some patchy fog around Thursday morning as well
with the light upslope surface winds and high dew points.

The models are dry for Thursday afternoon as the upper ridge
strengthens and the mean flow turns more southward. Any storms
that develop on the Palmer Divide Thursday afternoon should move
south rather than east into our area. High temperatures will be in
the middle to upper 80s, near normal for this time of year.

.LONG TERM...(Thursday night through Wednesday)
Issued at 230 PM MDT Wed Jul 26 2017

The long-term forecast period can be characterized by a large upper-
level pattern shift, bringing a relief to the very hot and dry
conditions observed over the past week or two. Overall, the upper
level ridge that dominated the weather pattern will slide further
west, eventually taking shape over Nevada, Utah, and Arizona.

What does this mean for the Tri-State Region? With the high pressure
ridge further west, this means our piece of the High Plains will be
under northwest flow aloft. As disturbances move around the high
pressure perimeter, storms should develop over the Rockies,
spreading east to southeast over the plains. Further, a cold front
will move through and more or less remain stationary along to south
of I-70, providing a boundary for additional storms to develop
along. Finally, winds at the surface are expected to remain from the
southeast to south, allowing for a persistent fetch of gulf
moisture. With this persistent flow of moisture, there should be a
chance for storms each day from tomorrow night onwards for most
locations. With regards to temperatures, indications are that we can
anticipate below normal temperatures for the foreseeable future.
Forecast calls for afternoon highs in the 80s for most of the
period. If cloud cover and precipitation persist on some days, highs
may not climb out of the 70s.

As far as potential for severe weather, with each day there will be
a chance for a strong to severe storm or two. MUCAPE of 1500 J/kg
should be present each afternoon/evening generally along the
Colorado border, precisely where the moisture shall persist.
Favorable 850-500 mb lapse rates should also remain further west
where temperatures will be warm. Also, as with recent days, wind
shear isn`t very impressive. There is an uptick in shear in the
vicinity of the stalled frontal boundary due to the extra
directional shear. During this extended forecast period, widespread
severe weather should not be anticipated. A few storms may be
capable of large hail and damaging winds.

One concern to watch for will be the potential for heavy rain and
flash flooding, especially for locations near the stalled front and
where storms are able to train over. Precipitable water values will
climb to 1.75" to near 2.00" by Saturday night, nearly 175 percent
of normal. This highlights how anomalously moist the atmosphere will
be at times. Saturday night is also when the best chance for storms
is expected as a decent shortwave trough pushes through. Will need
to watch Saturday and Saturday night for potential flooding concerns
as we approach this period. Another bout of high precipitable water
is expected Tuesday and Tuesday night as another disturbance moves
through. This period should be watched closely as well.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1046 PM MDT Wed Jul 26 2017

KGLD: MVFR ceilings will become IFR after 07Z with light upslope surface
winds and a very moist lower atmosphere. Rapid improvement 13Z-15Z
then VFR remainder of TAF period under surface high pressure.
Light NE winds overnight will transition to ESE by 18Z Thursday.

KMCK: VFR CIGS overnight with light NE winds. Some concern MVFR
CIGS will develop later tonight but confidence is not high. Added
a SCT deck at FL012 to cover uncertainty. VFR Thursday with light
ENE-E winds as surface high builds into the region.




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