Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 081129

Area Forecast Discussion
National Weather Service Denver/Boulder CO
529 AM MDT Thu Jun 8 2023

.SHORT TERM...(Today and tonight)
Issued at 400 AM MDT Thu Jun 8 2023

Water vapor imagery shows a trough over southern Nevada with
southeasterly flow over our forecast area. A stream of mid to
upper level moisture is extending over our forecast area coming
from storms in Texas. This mid to upper level moisture may be
producing some very light rain showers as some weak echos are
showing up on radar. A small area of enhanced vorticity is
associated with these clouds and this enhanced vorticity will be
over far northeast Colorado by this afternoon so much of the area
will be under NVA and light subsident flow aloft. This, along with
slightly less heating due to morning cloud cover, will result in
lower coverage of showers and storms today compared to the
previous days.

Models don`t seem to have a good grip on the location and
coverage of storms today. The current thinking is that there will
be three main areas for thunderstorm development. One area will be
the northern foothills and mountains of Boulder and Larimer
Counties as there will be the best low level convergence and
upslope flow there. A limited threat of flash flooding in the
recent burn areas will exist as storms could produce heavy
rainfall. The second area of focus for storms will be near the
Palmer Divide especially late this afternoon and evening. Moderate
instability will build in there and the terrain will aid in
developing weak upslope flow and surface convergence. Some of
these storms may generate an outflow boundary that moves northward
across the Denver metro that could initiate a few isolated
storms along the urban corridor. Overall, the urban corridor will
see low coverage of showers and storms today. In southern Elbert
and Lincoln Counties, there may be just enough deep layer shear,
due to enhanced westerly aloft there, for a storm or two to near
severe thresholds. Hail and damaging wind gusts will be possible
there. The last area of focus for showers and storms will be the
far eastern and northeastern plains. Popcorn storms will form this
afternoon and more organized storms may form later this evening.
Showers and storms could last well into the night in the far
northeast corner.

The below normal temperatures will continue today with highs in
the mid to upper 70s across the plains. Winds will be light and
there will be no fire weather concerns.

.LONG TERM...(Friday through Wednesday)
Issued at 239 AM MDT Thu Jun 8 2023

On Friday, the upper low will weaken over the Great Basin
but appears a weak wave ejects out and expected to move across
Colorado Friday afternoon and evening. Still only neutral to
slightly upward ascent noted on QG fields. Moisture will be in place
with precipitable water values ranging around a .5" over
mountains and up to an inch over the northeast plains. Given upper
40s/lower 50 dewpoints on the plains and decent instability given
expected good heating (highs nearing 80 on plains) resulting in
surface based CAPE values range from 800-1800j/kg. The flow aloft
does shift bit more stronger from the southwest so there should be
movement of storms out over the plains. Given decent CAPE and
increasing flow aloft could see a few marginally severe storms
with hail and winds. SPC also has targeted portions of the eastern
plains with a marginal threat of severe storms.

Saturday also looks to be an active day with even higher areal
coverage for showers and storms. Despite a ridge of high pressure
aloft over central Colorado, a cold front will drop southward
into eastern Colorado Saturday morning. There is some initial
stabilization behind the front but forecast soundings showing
enough destabilization for showers/thunderstorms during the
afternoon and evening. Precipitable water values approaching an
inch over the Front Range so heavy rainers and possibly marginal
severe hail with CAPE values of 800-1500j/kg.

Sunday looks to be the coolest day of the upcoming week with a
reinforcing shot of upslope flow and likely a stratus deck over the
plains Sunday morning along with ridge aloft over Colorado. This
will result in a capped airmass initially but forecast soundings
showing cin dissolving resulting in around 1000j/kg of MLCAPE and
perceptible water values closing in around an inch over much of
the plains. Given more cloud cover, temperatures will likely only
be in the 60s. Expect higher coverage of storms over the foothills
and higher terrain of the Palmer Divide.

On Monday, the next Pacific closed low continues to eject eastward
into Utah with an increasing southwest flow over Colorado and
increasing QG ascent ahead of the low and an upper jet nosing into
southeast Colorado.  Monday could see a higher severe weather threat
with ample instability and improving shear profile.

For Tuesday, the upper trof weakens and moves across the eastern
plains by late Tuesday afternoon with another round of showers and
storms, though possibly a bit weaker intensity than Monday. Finally,
by Wednesday and Thursday Colorado will be under a bit drier West
to northwest flow aloft and expect storm coverage somewhat lower
along with warming temperatures.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 523 AM MDT Thu Jun 8 2023

Winds will be light throughout the morning hours and into the
afternoon as they slowly veer towards northeast. Afternoon and
early evening storms will form mainly over the Palmer Divide and
Cheyenne Ridge. It is unlikely that a storm moves over any of the
three terminals but it is possible. Gusty winds, small hail, and a
brief drop in ceilings would be the main impacts from a
thunderstorm. Some showers may linger over the terminals past 02Z
until about 04-05Z but they will have minimal impacts. Skies will
slowly clear tonight with drainage winds developing.


Issued at 400 AM MDT Thu Jun 8 2023

All burn areas will have a limited chance of flash flooding today
with the Cameron Peak burn area having the highest chance. Storms
will not be as strong today as yesterday and they will be moving
a bit faster as a shortwave trough passes to the northeast of our
forecast area. Most models have very few storms forming in Grand
County so the flash flood threat for the East Troublesome and
Williams Fork burn areas will be very low and close to none.
Models are in good agreement that storms will form in the Cameron
Peak burn area which is why there will be a higher threat there.

Expect at least limited threats of flash flooding over the burn
scars through the period with the best chances this weekend with
the highest moisture levels, especially on Sunday. The threat for
flash flooding will slowly lower towards the middle of next week
as the airmass dries out a bit and storm motions increase.




SHORT TERM...Danielson
LONG TERM...Entrekin
HYDROLOGY...Danielson/Entrekin is the U.S. government's official web portal to all federal, state and local government web resources and services.