917
FXUS63 KGLD 221732
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1132 AM MDT Sun Sep 22 2024

.KEY MESSAGES...

- Showers will continue through the mid-day. Total rainfall
  amounts look to be around 0.25 inch for most of the area.
  Hazardous weather is not expected.

- Low temperatures in the mid to upper 30s are forecast for
  eastern Colorado by Monday morning, potentially allowing for
  some patches of frost. There is a concern for fog formation
  Monday morning, too.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 247 AM MDT Sun Sep 22 2024

Showers are moving across the area, albeit with less coverage than
was forecast 24+ hours ago. These showers, moving from the southwest
to the north and northeast and are expected to persist until the
late morning. An additional surge of dry is starting to move into
the area from the southwest, as easily seen at the 320K level, which
will limit the amount of QPF these showers can produce.

Around 18Z, the low will start moving out of the area. The following
pressure rises and additional dry air in lower levels will end the
showers in the southwest first, with the northeastern CWA seeing
rain last. By 21-23Z, all of the rain is expected to have moved out
of the area. QPF totals from this event look to be around 0.25 inch,
significantly lower than what many previous forecasts had.

The lower amounts of precipitation have also kept overnight
temperatures notably warmer, which gives most of the CWA the
potential at a midnight high today, and will increase day-time
temperatures slightly. 24 hour maximum temperatures look to be in
the mid 50s to low 60s while the day-time highs will be +/-3 degrees
of the 24 hour maximums. The cool temperatures are due to the
northerly winds, thick cloud cover, and slight evaporational
cooling.

As the low moves out of the area this afternoon/evening, a surface
high will traverse the CWA. Winds will weaken, shift from northerly
to southerly, and the sky will clear out as a result. This creates
an interesting setup overnight where two things could happen, a
mixture of both, or neither (which is looking more possible).
Potential one is patchy to widespread fog; with clear skies, light
winds, and recent precipitation, the environment is primed for fog
formation, with a couple of catches. The light winds that will exist
won`t be easterly (upslope) for long, if it all, lowering the fog
potential. Also, while an inversion does look likely to form,
surface layer moisture looks to be too dry from a lack of heavy
precipitation. Most likely scenario is valleys and locations
sheltered from the light breezes will see fog form. Confidence in
patchy fog is around 20-25%, widespread fog is around 5-10%.
Potential two is frost formation, mainly northwest of a line from
Kit Carson, CO to Wray, CO. The same conditions that make fog
possible overnight could allow for temperatures to drop into the mid
30s, allowing light, patchy frost to form. The big unknown, and
limiting factor, for the frost potential is what the dew points will
do overnight. If dew points remain around 40 overnight, the
potential for frost is near 0. However, if the dew points drop to
the mid 30s, patchy frost becomes more likely. Confidence for patchy
frost forming is around 15%. As mentioned before, there is a chance
(~10%) that both could occur; we could see fog in the eastern CWA
and frost in the western CWA. The potential for neither of these
possibilities to occur is around 30%. Southeast of the
aforementioned line will cool into the low to mid 40s overnight.

Monday will see the benefits of the surface high as clear skies and
weak southerly winds will dominate. Highs could rebound pretty
quickly and warm into the low to mid 70s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 159 AM MDT Sun Sep 22 2024

Below average forecast confidence. Forecast confidence
typically decreases with range -- `below average` in this
context is intended to communicate a further reduction in
confidence associated with /inherent to/ increased pattern
complexity -- e.g. patterns with cut-off waves, multibranched
wave interactions and potentially significant forms of
constructive/destructive interference or feedback.

Guidance continues to diverge Tue-Tue night.. as a pronounced
upper level ridge progresses east across the Intermountain West
and Rockies. Solutions via recent (00 UTC 09/22) operational
runs of the GFS/ECMWF are consistent only in the sense that they
remain inconsistent. Both models suggest that some degree of
northern and southern stream jet phasing (or interaction) within
a complex split flow regime on the eastern periphery of the
advancing ridge will foster the development of a closed low
somewhere invof the Central/Northern MS River Valley Tue night.
Poor model-to-model and run-to-run continuity essentially
precludes further discussion, other than to say that.. whatever
the outcome, hazardous weather seems unlikely. Steering the
forecast toward climatology remains the most viable course of
action at this time.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1127 AM MDT Sun Sep 22 2024

For KGLD & KMCK... VFR conditions are expected through the
period, though GLD may see some 2500-3000ft ceilings for the
first hour or two of the period. Winds are forecast to remain
from the north until around sunset, when winds will then shift
to out of the southwest at 5 kts or less. There is a low chance
for fog as temps lower to near dewpoints overnight, but the
westerly component of the winds should hinder fog development.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.

&&

$$

SHORT TERM...CA
LONG TERM...Vincent
AVIATION...KAK