438
FXUS63 KGLD 122009
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
209 PM MDT Fri Jul 12 2024

.KEY MESSAGES...

- Record to near record highs through Monday.

- Isolated showers and thunderstorms possible this afternoon and
  evening and Saturday afternoon/evening. Wind gusts up to 60
  MPH possible with these storms.

- Increase in rain chances middle of next week along with a cool
  down.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 202 PM MDT Fri Jul 12 2024

Latest upper air analysis shows an upper level ridge centered over
Utah.  Underneath, and around the ridge, areas of clouds were
forming as temperatures reach convective values.  At the surface a
dry line of sorts was located on the western edge of the forecast
area. Cumulus clouds were developing along it, moving south, along
with isolated storms over Lincoln County.

For the rest of the afternoon, mesoanalysis shows MLCIN over most of
the forecast area, except for Eastern CO.  An upper level short wave
trough will form over East Central CO, along with a weak LLJ nose.
Would not be surprised if isolated showers/thunderstorms form where
this lift will occur.  Model data has become less optimistic about
it as the day has progressed, so confidence is quite low any storms
will form over East Central CO.  However, this is a similar
environment to yesterday when isolated storms did form during the
late afternoon. The main threat with these storms will be wind gusts
up to 60 MPH.

Tonight the isolated thunderstorm activity will end by 8 PM MT or
so, if any do form.  There were chances for storms in the forecast
after midnight.  However the latest model data is showing subsidence
where the storm chances were, so have removed them.

Saturday and Sunday the hot weather will continue as the ridge edges
slowly to the east.  The current forecast has highs in the low 100s
for the forecast area both days.  Heat Index values will be 95-105F
both days.  In addition the Heat Risk values will be in the Moderate
to Major category for Saturday, then Major to Extreme category on
Sunday (with some Extreme areas in Eastern CO).  Lows will be rather
warm, only falling to the low 70s, specifically over the eastern half
of the forecast area.

On a side note, the 10th percentile data for high temperatures has
values of 100-105F for both days.  Records may be tied or broken on
Sunday.  For simplicity, and in coordination with surrounding
offices, have decided to issue a Heat Advisory for the entire
forecast area for these two days.

Saturday a chance for isolated thunderstorms was added in for the
central part of the forecast area given a similar setup compared to
today.  Model data looks slightly more favorable for storm
development than today.  However confidence is still low given the
little to no CAPE to work with and the deep dry layer below any
clouds that form.  If any storms do form the main threat will be
gusts up to 60 MPH.

Relative humidity values will fall to 15% or so Saturday and Sunday
afternoons for the west half of the forecast area.  However winds
will remain light enough to not be a concern for fire weather.

&&



.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 202 PM MDT Fri Jul 12 2024

Main focus for this is two aspects, the cool down mid week and the
rain chances returning, especially with the cold front mid week.

The upper level ridge will continue to build east over the Plains on
Monday, yielding even hotter temperatures than Sunday.  However, the
heat dome ends after Monday when a closed low in Canada sends a
trough axis south over the Plains.  This causes the ridge to be
pushed back west, along with the hot, dry air mass.

Relative humidity values will fall to 15% or so Monday afternoon for
the southern half of the forecast area.  However winds will remain
light enough to not be a concern for fire weather.

Another, somewhat strong, upper level short wave trough rounds the
ridge Tuesday with another round of cooler air behind it.  Both the
national model blend and the EC/GEFS ensembles show the best chance
for the week for rainfall occurring on Tuesday night.

The coolest highs will be Wednesday, with a gradual warming trend
through the rest of the week.  Rainfall chances decline after
Tuesday as well due to the slow laminar flow over the forecast area
between the ridge to the west and the trough to the east.


&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1145 AM MDT Fri Jul 12 2024

VFR conditions forecast for the TAFs. Light and somewhat
variable winds can be expected through the TAF period. Tonight
the LLJ moves over the forecast area. This may lead to LLWS at
both sites.

&&

.CLIMATE...
Issued at 202 PM MDT Fri Jul 12 2024

Saturday high temperature records
            Record  Year

Yuma        108     1954
Burlington  103     1934
Goodland    108     1934
Tribune     107     1934
Colby       111     1934
McCook      108     1954
Hill City   115     1934


Sunday high temperature records
            Record  Year

Yuma        105     2010
Burlington  105     1925
Goodland    107     1934
Tribune     107     1934
Colby       109     1934
McCook      109     1954
Hill City   113     1934


Monday high temperature records
            Record  Year

Yuma        102     2006
Burlington  103     2000
Goodland    106     1925
Tribune     108     2000
Colby       108     1925
McCook      112     1925
Hill City   113     1934


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory from noon MDT /1 PM CDT/ Saturday to 9 PM MDT
     /10 PM CDT/ Sunday for KSZ001>004-013>016-027>029-041-042.
CO...Heat Advisory from noon Saturday to 9 PM MDT Sunday for
     COZ090>092.
NE...Heat Advisory from noon MDT /1 PM CDT/ Saturday to 9 PM MDT
     /10 PM CDT/ Sunday for NEZ079>081.

&&

$$

SHORT TERM...JTL
LONG TERM...JTL
AVIATION...JTL
CLIMATE...JTL