225
FXUS63 KGLD 030700
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
100 AM MDT Wed Jul 3 2024

.KEY MESSAGES...

- Thunderstorms in Colorado may increase in coverage and track
  eastward into Kansas early Wednesday morning. An isolated severe
  storm cannot be ruled out, mainly south of Highway 96 in
  southeast Colorado and southwest Kansas.

- Severe thunderstorms are possible Wednesday afternoon and
  evening. Significant uncertainty exists with regard to
  thunderstorm location and coverage.

- Breezy to gusty 4th of July; normal to below normal
  temperatures into early next week.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 113 PM MDT Tue Jul 2 2024

Mid level troughing is present across the area currently with a weak
cold front draped across southern portions of the area. 700mb
moisture looks to continue for the most of the area keeping skies
partly to mostly cloudy. Some thicker stratus looks to impact
northern portions of the area as well to start the afternoon with
continued overcast skies.


Weak shortwave which is currently moving off of the Rockies will be
the focal point for storm development as it reaches the Palmer
Divide. RAP has been showing an increase in 700-500 mb moisture
correlating with continued CAM initiation roughly around the Flagler
area around 20Z. Strong to marginally severe weather is possible
initially due to a lack of instabilty as dew points in the mid to
upper 40s are in place. As this continues to trek east into better
moisture do think a slow intensification process looks to occur. RAP
forecast soundings indicate an environment that would be
favorable for 70 mph winds and hail up to two inches in a fully
mature cell.

Cold front will slowly lift north as a warm front tonight. Another
weak wave will move off the mountains and with an increasing
LLJ will add to lift across southern portions of the area. HRRR
is currently suggesting an environment that would be supportive
of severe weather overnight across SW portions of the area with
stronger moisture advection. RAP and NAM are not as aggressive
on the moisture return which would keep elevated CAPE values
down some. Thinking there is some potential for overnight hail
around half dollar size with a mature cell. Showers and storms
will expand in coverage into the morning hours to the east. Will
leave the patchy fog in the forecast for tonight across the
east as the RAP continues to show around 90% surface RH and
light easterly winds which is supportive of fog development;
however if the showers and storms do occur that will end any fog
potential where the rainfall is ongoing.


RAP consistently has been showing a signal for low stratus to hang
around the majority of the day Wednesday so have trended high
temperatures down a few degrees along and east of Highway 27 where
this is forecast to occur. The main focus for the day Wednesday will
be on another round of severe weather. A sharp surface trough will
be across the region. A 250mb jet streak will also be developing
throughout the day to provide upper level support. A dry line looks
to be situated across Colorado which will be the focal point for
initiation, potentially as early as 1pm MT. Supercells capable of
very large hail initially, perhaps a tornado threat can develop as
well if a cell can remain discrete into the mid to late afternoon as
SRH increases. Storms are then forecast to grow upscale with outflow
boundaries as they interact with a very moist air mass and a
strengthening LLJ as it moves to the east. Do have some concerns
of a bow echo developing as 700mb winds increase into the
evening hours; if this does occur then wind gusts in excess of
70 mph will be on the table. There may be some potential for a
quick spinup squall line (QLCS) tornado as well along the
leading edge as the RAP does indicate 25-50 j/kg of 0-3 CAPE.
Depending on the orientation of the line if its W to E or NW to
SE oriented will be dependent on the tornado threat as the 0-3
shear vector looks to be oriented more SE to NW. However there
is some potential that storms will be more isolated and/or be on
the weaker side due to concerns about instability especially if
the cloud cover does in fact linger all day. There also does
appear to be some concern on the timing of the wave off the
Rockies as well which would turn the severe threat into if
severe storms in the Nebraska Panhandle can follow a CAPE
gradient into the CWA. So there area still quite a bit that
needs to be worked out so continue to stay up to date with the
forecast.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 100 AM MDT Wed Jul 3 2024

Friday...the forecast area is forecast to be under northwest flow
aloft, in between low pressure to our north and east and a
strengthening ridge to our west. GFS/NAM 700-500mb relative humidity
forecasts advertise a weather system moving through the
western/southwestern 1/3-1/4 of the forecast area during the
afternoon with potentially another moving through the entire area or
much of the area overnight if the NAM/ECMWF models are correct.
Presently, we`ll cap the pops at 20% for the time being. High
temperatures are forecast to remain below normal in the lower to
upper 80s with low temperatures in the 55 to 60 degree range.

Saturday...not much change in the general 500mb pattern when
compared to Friday. There is some agreement from the GFS/ECMWF/GEM
models that another weather system will move into the eastern part
of the forecast area during the afternoon hours from the southwest,
supporting NBM 20%-30% pops for thunderstorms generally east of
Highway 27. Overnight, there may be some type of weather system
moving through from the northwest, supporting 20%-40% chances for
thunderstorms. Timing of when this system arrives in somewhat in
question. GFS/ECMWF/GEM 850mb temperatures are showing a little more
spread compared to 24 hours ago with the GFS the warmest. If it were
to verify using typical mixing at 850mb, high temperatures would be
a few degrees lower than currently forecast. Presently, highs are
forecast to be in the upper 80s to lower 90s. Low temperatures are
forecast to be in the middle 50s to lower 60s.

Sunday...500mb pattern is showing an upper level trough axis moving
through within the broader pattern featuring troughing over the area
and ridging to our west. With surface high pressure moving in, high
temperatures look to be cooler than Saturday. Just how much cooler
is the question as ECMWF/GEM 850mb temperatures are in the 13C to
18C range with the GFS in the 19C to 21C range. Given the spread, no
chance of improving the current temperature forecast of highs in the
upper 70s to middle 80s. Low temperatures are forecast to be in the
50s. Regarding rainfall chances, there appears to be at least a 20%-
30% chance as there is some moisture in the 850-500mb layer moving
through which with the trough axis moving through should support at
least isolated to scattered chances for thunderstorms.

Monday and Tuesday...we remain under northwest flow aloft with slim
(20%) chances for thunderstorms to move off the Colorado front range
and into the area during the late afternoon through overnight hours.
High temperatures Monday are forecast to be in the 85 to 90 degree
range with 90 to 95 Tuesday. Low temperatures are forecast to be
in the middle 50s to lower 60s.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1045 PM MDT Tue Jul 2 2024

Aside from a potential for showers/thunderstorms at the GLD
terminal overnight.. and at either terminal Wed aft/eve.. VFR
conditions should otherwise prevail. Confidence in thunderstorm
location and coverage is low enough to preclude explicit
mention at this time. Light easterly winds will shift to the
south and increase to 15-25 knots late Wed morning into Wed
afternoon.

&&

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

&&

$$

SHORT TERM...Trigg
LONG TERM...99
AVIATION...BV