945
FXUS65 KBOU 111146
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
546 AM MDT Thu Jul 11 2024

.KEY MESSAGES...

- Warmer again today with scattered showers and thunderstorms over
  the mountains. Slight chance of a thunderstorm in the northeast
  corner.

- A heat wave is expected Friday through Monday with temperatures
  reaching 98 to 105 degrees across the urban corridor and plains.
  Overnight lows will be near 70 across the urban heat islands,
  resulting is limited relief from the heat.

- A heat advisory is in effect Friday, Saturday, and Sunday from
  10a-8p for the I-25 corridor. It will be hot everywhere,
  including outside of the advisories, so take steps to limit
  outdoor activity and find ways to cool off and stay hydrated as
  much as possible.

&&

.SHORT TERM /Through Friday/...
Issued at 239 AM MDT Thu Jul 11 2024

We`re starting to see an accumulation of moisture at the top of
the mixed layer around the edge of the upper high, and that zone
will be over central and eastern Colorado today. For the most
part, it`s a shallow layer and probably won`t result in more
shower/storm activity this afternoon, but there will likely be a
bit more cloud cover especially in the late afternoon and evening.
This will also likely limit the additional warming today to just a
few degrees although mid level temperatures are warming a bit more
than that. Previous forecast temperatures look good with mid to
upper 90s on the plains. We`ve got lows tonight about 5 degrees
warmer counting on some clearing, but if we wind up with more
clouds overnight these numbers may need to come up more.

&&

.LONG TERM /Friday night through Wednesday/...
Issued at 239 AM MDT Thu Jul 11 2024

The extended forecast will begin with the arrival of the highly
anticipated high pressure system that is expected to bring a
prolonged period of above average temperatures to the region. Given
the prolonged duration of this heat event, the impacts on public
health, particularly for vulnerable populations, remain a concern.
Beginning Friday, high temperatures are expected to be 98-103
degrees each afternoon therefore, Heat Advisories have been issued
for Friday, Saturday, and Sunday beginning at 10 AM and continuing
through 8 PM each day for metro Denver and the I-25 corridor. While
this has been mentioned in previous discussions, the message remains
the same in that residents in these areas and all across the plains
should remain vigilant in practicing heat safety measures, and
are urged to take precautions to prevent heat-related illnesses,
including staying hydrated, avoiding prolonged outdoor activities
during peak heating hours, and checking on vulnerable neighbors
and pets.

Friday will bring N/NW flow aloft overhead as the ridge finally
shifts east over Colorado. This is expected to raise 500 mb heights
to roughly 2 - 2.2 sigma above normal through the weekend. Guidance
agree that 700 mb temperatures will be notably elevated and range
from 19C to 21C. These anomalously high mid-level temperatures will
contribute to the hot surface temperatures that are forecast to
reach triple digits across the plains Friday through Sunday, with
portions of the plains remaining slightly above 100 degrees into
Monday, mainly for the South Platte Valley. While Monday is not
currently included in the issued heat highlights, ensembles continue
to show potential for the 100 degree threshold to be met that day as
well across the same areas that are already under the Heat
Advisories. This will continue to be monitored through the coming
days, however, it WILL be another HOT day across the plains whether
any highlights are issued or not. For example: the current ECMWF,
GFS, and CMC ensembles show Fort Collins reaching a high temperature
of 99, 100, and 99, respectively on Monday afternoon.

Precipitation chances look to remain anchored to the higher terrain
through the weekend as the plains are expected to stay hot and dry
with limited potential for cloud development under subsident
conditions. Some high-based convection will be possible that could
bring some gusty winds and little rainfall. With dry conditions in
place across the forecast area, isolated dry lightning is expected.
Moisture is expected to increase by Tuesday while temperatures are
expected to start their decrease towards more climatological
normal values.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 545 AM MDT Thu Jul 11 2024

VFR through tonight. Light southwest winds will become northwest
after 15z and then east to northeast around 10 knots by 20z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 10 AM to 8 PM MDT Friday for COZ038>040-043.

Heat Advisory from 10 AM to 8 PM MDT Saturday for COZ038>040-043.

Heat Advisory from 10 AM to 8 PM MDT Sunday for COZ038>040-043.

&&

$$

SHORT TERM...Gimmestad
LONG TERM...Bonner
AVIATION...Gimmestad