Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 202150
Area Forecast Discussion
National Weather Service Goodland KS
350 PM MDT WED JUL 20 2016
.SHORT TERM...(This afternoon through Thursday)
Issued at 127 PM MDT Wed Jul 20 2016
Large scale mid-upper level ridging continues to dominated the
pattern across the US, with monsoonal flow (apparent on WV imagery)
rotating around the western edge of the ridge.
Regarding heat advisory: Temperatures are still in the process of
increasing early this afternoon and already in the mid to upper 90s
for most locations. Tds have mixed lower in the west (as expected),
however they have held up in our east and heat index values should
approach advisory criteria before temperatures begin decreasing.
There is a little less certainty on highs Thursday due to the
possibility of better thunderstorm coverage (discussed below),
however consensus continues to favor at least similar highs as today
and possibly higher Tds raising the possibility some eastern
locations could see heat indices approach 110. Friday highs are
discussed in the long term section. Confidence continues to remain
high enough to maintain current advisory through Friday, though
there could be a larger spread in heat index values in advised area
than currently indicated.
This afternoon-Tonight: Shower/thunderstorm activity has already
developed over higher terrain in colorado and mean flow sill tend
to bring this towards the northwest part of our CWA. Local CAPE
values are relatively weak (500 J/KG MU CAPE), CIN is very strong,
and with main region of forcing well to the west I am not confident
we would see see local initiation this afternoon in all but our far
west near surface trough axis. Better chances would be associated
with activity spreading eastward or outflow weakening the CIN
locally. Strongest signal from high resolution guidance is in our
far western CWA, and this is where I kept chance PoPs.
Thursday: There is a shift in the ridge to the east allowing for
southwest flow to develop over our cwa. This shifts the monsoonal
axis towards northwest Kansas and results in increasing in moisture
profiles and forcing above 700mb. Higher resolution guidance still
favors isolated to widely scattered activity, however considering
the shift in pattern I could see coverage being better than
consensus indicates. CAPE values increase to the 1500-2000 J/KG
range, however effective bulk shear will roughly be in the 15 kt to
25 kt range, so an organized severe threat is unlikely. PWAT values
will increase to be almost 1.5" and considering warm air mass and
skinny CAPE profiles we could see localized heavy rainfall with any
.LONG TERM...(Thursday night through Wednesday)
Issued at 213 PM MDT Wed Jul 20 2016
Hot temperatures continue to be a concern through the end of the
work week while precipitation chances persist through the majority
of the long term.
Thursday night: At the start of the period, high pressure remains
centered over the CONUS. A weak disturbance is expected to pass
across the region Thursday night, bringing thunderstorm chances.
There is some potential for severe storms Thursday evening for
northeast Colorado/southwest Nebraska as a cold front advances
towards the Central Plains. Widespread organized severe weather is
unlikely, but a few stronger storms could develop as the cap weakens.
Friday through Saturday night: A shortwave trough moves from the
Pacific Northwest towards the northern Plains along the Canadian
border, breaking down the ridge and sending the high pressure to the
west. With the weakening ridge, disturbances pass through the flow
which starts to become more westerly for the northern half of the
country. Cooler air begins to make its way south towards the High
Plains. As for temperatures, highs mainly in the upper 90s to low
100s on Friday in combination with dewpoints in the low 60s could
make for dangerous heat with heat indices near 105 possible
generally along and east of line from Stratton, Nebraska to Russell
Springs, Kansas. As a result, the heat advisory continues from the
start of this period through Friday afternoon with lows Thursday
night only lowering into the 70s for that area. Temperatures start
to decrease Saturday with highs mainly in the 90s.
Sunday through Wednesday: Shower and thunderstorm chances persist
next week with a boundary nearby Sunday into Monday. Guidance
differs on placement and timing, but several upper level
disturbances appear to pass through the flow during the extended.
With the ridge broken down and cooler air pushing south into the
region, temperatures will be more seasonal during this time with
highs in the upper 80s to low 90s and lows in the 60s. Guidance
indicates drier weather on Wednesday as ridging from the west
builds back into the region.
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 345 PM MDT Wed Jul 20 2016
For KGLD and KMCK, vfr conditions expected through the period.
South to southwest winds 10kts or less expected from taf issuance
through 11z before veering to the west then northwest at similar
speeds through 19z. After 20z Winds becoming variable in
direction at speeds under 5kts. Only some mid and high clouds
expected. Both terminals may experience a thunderstorm or two from
03z-09z...chances right now too low to include in forecast.
KS...Heat Advisory until 7 PM CDT Friday for KSZ002>004-014>016-028-
NE...Heat Advisory until 6 PM MDT /7 PM CDT/ Friday for NEZ079>081.