947
FXUS65 KBOU 132338
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
538 PM MDT Sat Jul 13 2024

.KEY MESSAGES...

- Heat wave continues through Sunday. High temperatures this
  afternoon will be in the upper 90`s to lower 100`s with highs
  reaching 100 to 105 degrees across the Urban Corridor and plains
  on Sunday. Important to take steps to limit outdoor activity,
  find ways to cool off, and stay hydrated as much as possible.

- A Heat Advisory is in effect both today and Sunday 10 am to 8 pm
  for all of northeast and east central Colorado.

- Monitoring dry lightning threat and possible new fire starts
  today and especially Sunday.

- Slight heat relief expected by Monday, but more so by Tuesday
  and Wednesday. Increasing chance of showers and thunderstorms
  for that period.

&&

.SHORT TERM /Through Sunday/...
Issued at 231 PM MDT Sat Jul 13 2024

Isold to widely sct hi based convection was over portions of the
higher terrain this aftn with the plains capped at this point.
Still looks like there is some potential for a few storms to develop
near the Cheyenne Ridge by late aftn and then move southeast thru
the early evening hours.  MLCAPE was around 1000 j/kg where low
level moisture hasn`t mixed out over the plains, so its possible a
few stronger storms could occur northeast of a Greeley to Limon line
thru the evening hours.  Otherwise, where larger T-TD spreads exist
there will be a threat of gusty microburst winds due to favorable
DCAPE.

On Sun, an upper level high will continue over the area as a slow
increase in mid level moisture occurs.  There should be an increase
in higher based shower/tstm coverage over the higher terrain.
However, activity will produce limited rainfall with mainly gusty
winds and lightning.  Meanwhile, outflow boundaries from
higher terrain activity will move across the plains by late
aftn.  As these boundaries move across, they may trigger isold to
widely sct showers/tstms over the plains.  Once again, with
favorable DCAPE activity will produce gusty winds but mainly
limited rainfall.

As far as highs, will keep highs in the 98 to 104 across the
plains. Depending on how quickly cloud cover moves across, this could
affect highs by a few degrees, especially along the I-25
Corridor.

&&

.LONG TERM /Sunday night through Saturday/...
Issued at 231 PM MDT Sat Jul 13 2024

Monday, a weak wave riding the east edge of the upper ridge will
bring a backdoor cool front across the plains. This will bring
northeast-easterly flow across the east plains. This along with
increasing mid-level moisture (more cloud cover) will provide subtle
relief from the previous few days with temperatures in the mid to
upper 90s instead of steamy low 100s. Instability remains marginal
(< 500J/kg CAPE). Model soundings show the classic inverted v
sounding profiles with mid-level moisture and sufficient dewpoint
depressions, indicative of gusty outflow wind potential. Model DCAPE
fields reflect this well with values in the 1000-1500 J/kg range.
This will support scattered showers and thunderstorms with some
capable of gusty outflow winds up to 50 mph. The higher
probabilities (>50%) will be confined to the mountains/foothills and
Palmer Divide. More moisture will decrease the dry lightning threat;
however, there is still a low chance given drier lower levels on the
foothills and adjacent plains.

An upper level trough moving across the Great Lakes region extends
far enough south to weaken the ridge aloft on Tuesday. This should
bring another reinforcing push of cooler air from the north and
northeast. A plume of above normal moisture extends further east,
across northeast Colorado, especially in the mid-levels. However,
some moisture returns back to the lower levels thanks to easterly
flow as well. Temperatures trend cooler with highs in the upper 80s.
More instability and moisture will lead to higher
coverage/probabilities of shower and thunderstorms in the afternoon.
Similar conditions expected Wednesday with higher coverage scattered
showers and thunderstorms in the afternoon.

Confidence decreases toward later in the week with regard to the
position of an upper level ridge. Ensemble guidance shows the upper
ridge retrograded west, but there are some differences in how far
west/east the thermal ridge positions which will determine
temperatures later in the week. If it stays, further west this will
bring continued cooler and unsettled. For now, sticking with
ensemble means (highs upper 80s to low 90s plains) until there is
more agreement on the position of the ridge.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 535 PM MDT Sat Jul 13 2024

Threat of gusty outflow winds this afternoon in KDEN vicinity
appears to be diminishing, with most activity remaining due N of
the terminal, and mostly stable conditions in place across the
Denver metro. Winds will rotate CW through this evening as they
return to S/SW drainage. Wind directions Sunday highly uncertain,
and potential quite variable, with speeds mostly under 10 kts
through early afternoon. Higher potential for high-based showers
and gusty outflow winds after 21Z. VFR conditions will prevail for
all terminals.

&&

.FIRE WEATHER...
Issued at 231 PM MDT Sat Jul 13 2024

Elevated fire danger will remain in place across most of the area on
Sunday. Well above normal temperatures along with dry conditions
and low humidity will continue. There will be some dry lightning
as well, especially over the higher terrain.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM MDT this evening for COZ038>051.

Heat Advisory from 10 AM to 8 PM MDT Sunday for COZ038>051.

&&

$$

SHORT TERM...RPK
LONG TERM...Mensch
AVIATION...Rodriguez
FIRE WEATHER...RPK