Area Forecast Discussion
Issued by NWS Goodland, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KGLD 250149

Area Forecast Discussion
National Weather Service Goodland KS
749 PM MDT SUN JUL 24 2016

Issued at 747 PM MDT Sun Jul 24 2016

Extended the severe thunderstorm watch one more hour due to wind
gusts in thunderstorms still nearing 60 MPH occasionally. Storms
should continue to weaken as they move east.

UPDATE Issued at 533 PM MDT Sun Jul 24 2016

Updated the chances for rainfall for the evening based on latest
data and storm trends. As storms progress east they will enter a
corridor of much higher CAPE ranging from 1000-2500j/kg as evident
on SPC Mesoanalysis. Am thinking this corridor is along the
frontal boundary and drapes southeast following the front into
Southwest Kansas. Storms are also moving into deep layer shear of
25-45 KTS or so. Am thinking storms will continue to increase in
intensity as they move east. However east of the KS/CO border the
environment becomes more stable north of Highway 40. The storms
will weaken as they move into the more stable air. The question
is how far east will they remain severe before weakening, thus
the reason for including a tier of KS counties in the watch.

Storm activity should propagate southeast following the corridor
of higher CAPE values into Southwest Kansas where lift will also
increase along the front by mid evening. By this point the deep
layer shear will have moved further north or will be in the
process of decreasing, causing the storm intensity to decline
leading to more of a heavy rain threat.

There is some elevated instability over the southeast quadrant of
the Tri- State Area during the latter half of the evening, so
some chances for storms are justified north of the front. However
believe the majority of the storm activity will be south of the
Tri-State Area during the latter half of the evening.


.SHORT TERM...(This evening through Monday)
Issued at 1238 PM MDT Sun Jul 24 2016

Thunderstorms will develop later this afternoon in northeast
Colorado in the post frontal upslope regime as a weak shortwave
trough ejects out of the Rockies. Instability axis will reside
along the cool side of the front located roughly along the western
and southern boundaries of the forecast area. Deep layer shear
will be 30-40kts. These parameters suggest a few severe storms
will be possible and SPC accordingly raised the risk level to
slight. Although some of the short term convective models have
backed off on their QPF the synoptic scale models still show
copious QPF this evening in the western third. Given mean 0-6km
winds of 5kts or less, slow-moving storms will be possible with
locally heavy rainfall. Some models show 3"+ in northeast
Colorado. Will carry likely pops in Colorado tapering to chance in
northwest Kansas and slight chances in southwest Nebraska where
instability is very limited. Storms should wind down after
midnight as they trek southeast and out of the local area. Some
low clouds and perhaps patchy fog will develop around sunrise
Monday morning with persistent light upslope winds and low level

Upper heights actually rise on Monday as the ridge over the Four
Corners appears to briefly nudge northward...perhaps aided by
subsidence behind the convective complex. As a result, think
Monday will be dry during the day with the next upper disturbance
not arriving until Monday night. Temperatures will once again be
near to slightly below normal.

.LONG TERM...(Monday night through Sunday)
Issued at 232 PM MDT Sun Jul 24 2016

The area of high pressure aloft over the southern plains retrogrades
further west over the southwestern U.S. through the work week.
Westerly flow aloft across the northern tier of states turns
northwest as a trough deepens over the Mississippi valley region
downstream of the upper ridge amplifying over the west.

Temperatures are expected to remain near of somewhat above normal
for the period. Models differ on the details, but all seem to
indicate diurnal convective activity forming late each day moving
off the Rockies and over the plains during the evening and
overnight hours. Tuesday night and Friday night still seem to be
the favored time periods for the highest possibility of
thunderstorms and rain showers across the forecast area. These
periods correspond to a couple of the stronger short wave troughs
moving across the forecast region.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 533 PM MDT Sun Jul 24 2016

VFR conditions expected for the TAFs. Am expecting the storm
activity to just miss KGLD, but close enough to include a vicinity
thunder in the TAF. If any storms do move over KGLD will be during
the mid evening hours.  KMCK will be well north of almost all the
storm activity.


.GLD Watches/Warnings/Advisories...


AVIATION...JTL is the U.S. government's official web portal to all federal, state and local government web resources and services.