Video summary
The weather forecast for Longmont from September 3rd to September 10th, 2026, begins with a mix of dry conditions and increasing storm activity as the season progresses. Early in the week, specifically on Thursday and Friday, the region will experience hot and dry air with only a slight chance of thunderstorms, while flooding risks are noted elsewhere in the country like Tucson. However, the situation shifts significantly by Saturday and Sunday, when severe weather chances remain high across the eastern part of Colorado due to moisture surges from the Gulf and Pacific. These days are expected to be particularly stormy, with afternoon storms bringing precipitation that could lead to localized flooding, especially as a dying hurricane dumps cold water and moisture into the western United States.
As the week continues into mid-September, temperatures will begin to drop from the upper 80s toward the low 80s by the 14th, though nights will remain unusually warm, hovering around 53°F before dipping slightly lower. Despite the cooling trend, the area will stay above normal temperatures for much of the period, with heat lingering over the Great Plains and Colorado until a zonal flow pattern establishes itself around the 18th or 19th. This shift brings cooler air from the north but also sets the stage for a significant increase in rainfall, with Wednesday standing out as the wettest day of the week with an expected third of an inch of rain. The moisture levels will fluctuate, creating a pattern where dry spells are quickly followed by surges of humidity that fuel thunderstorm development across the western slopes and eastern plains.
Looking beyond the immediate week, the broader September outlook suggests that Longmont is currently on the edge of receiving above-normal precipitation, with a 50/50 chance of exceeding median rainfall for the month. While drought conditions are improving nationally and Arizona is seeing substantial water replenishment, Colorado will still face periods of intense heat followed by heavy storm coverage. The forecast indicates that the next five days will see spotty rain where most residents get something, but the following ten days promise much heavier rainfall as moisture continues to surge through the region. Meteorologists are keeping a close watch on winter snowpack forecasts, which predict 110 to 120% of normal accumulation, hinting at a potentially wet and snowy winter ahead if current precipitation trends hold true.
Read the full video transcript
Welcome to the weather forecast for the
week beginning Thursday, September 3rd,
2026. This is chief meteorologist John
Ensworth for Longmont Public Media. I
was looking at the
uh my computer over the weekend. Did I
record a video last week? Sure, I did. I
must have. Uh no. So, I'm into four
weeks having students here and a month
and a half of being at a new school and
boy, time just seems to be going faster
and faster. So, sorry about that. Here
we are back at it again. Thursday,
September 4th, we'll have a third
quarter moon in the morning sky.
The sun is fairly quiet. We have a
sunspot or two just coming in here, but
we had a big coronal mass ejection over
on the left limb last night. Um, so
there should be some really active stuff
coming around this weekend. Uh, Saturday
sunrise 6:32 a.m. since at 7:25 p.m. and
we've lost about 36 minutes since I last
recorded a video. Yeah, still I'm
looking straight into sunlight going
east in the uh 6:20 in the morning. So,
yeah, can't wait for it to stay dark.
Let's take a look at uh drought
conditions over the last two weeks. And
you can see they've actually gotten
better in many places. uh the edges or
margins of the more severe drought are
um kind of being whittleled back and
nationally kind of shifting towards
Texas, but still some drought out there.
Arizona is actually doing really well
and it's going to get a lot more
precipitation as we'll see. And so the
September outlook has Arizona, Utah, and
the western slopes are getting drought
removal or improving. So, lots more
water to come. Smoke, we're in the
clear. Uh, wonderful. And for
precipitation, we've gone from 75 to 77%
of median for this date. So, hey, that's
good. We're uh going in the right
direction. I'm going to keep an eye on
winter forecasts. our weather bell uh is
forecasting
110 to 120% snow pack of normal and um
2° or something like that uh colder than
normal. So might actually be a real
winter um and you'll have some snow and
some skiing. So precipitation wise you
can see yeah some fairly good amounts
half inch to an inch hit maybe a third
of the state in spots.
Looking at the severe weather
climatology going through July, August,
first week of September. Still have a
little elevated risk. Um, nothing this
week that I can see is going to do that,
but we'll see.
For Thursday, just a chance of
thunderstorms. Friday, just a chance of
thunderstorms. The sphere is out in
Nebraska and
oh, no, Kansas, sorry. and Saturday
still thunder thunderstorm chances
remain over 2/3 of the eastern part of
Colorado. So we are in the dry on
Thursday
with some flooding possible around
Tucson. Uh expands into western New
Mexico and the thunderstorms return on
Friday and Saturday thunderstorms around
with front draped up in Wyoming. Not
going to do much. Our normal highs are
starting to drop pretty quickly. what's
actually happening is not dropping very
quickly, but 83 down to 80, we expect 80
uh as a high in 10 days from now. So on
the 14th, midmon, um you can see the
actual [clears throat] forecast
temperatures do drop into the upper 80s
and even mid 80s, low 80s by the end. So
nighttime temperatures are staying way
above the 53 down to 49. Boy, that would
actually kind of feel chilly. And
they've got elevated storm chances on
Sunday, Monday, and next Saturday with
some precipitation between. So this week
could be a lot more stormy. Take a look
at Sunday, Monday, clouding up. Sunday,
Monday, uh increasing chance of
afternoon storms, some precipitation,
and then next Saturday, storms again,
but some rain midweek. Wednesday, third
of an inch. It's the wetest of all. And
pretty windy on Sunday as well. So
Sunday, Monday is going to be a
definitely a weather couple weather days
to watch.
We have dry air over us right now on
Thursday. So not much in the way of
clouds at all out there. Let's put the
upper air 500 millibar map into motion.
And the big ridge is out in the middle
of the nation. So it's like right over
Nebraska and Kansas there. And that
allows this flow to come around from the
Gulf and and the Pacific and up across
Colorado. So we have a pretty continuous
supply of moisture.
Yeah, it wiggles around now sitting by
Thursday, Friday, it's down to the
southeast part of the nation with the
ridge up into the Dakotas trough kind of
sitting off the west coast. uh by the
13th 14th that ridges over the Tennessee
Valley and we are definitely still
getting flow from the south. So nice.
Now something weird happens by the 16th
it pops back to the panhandles of Texas,
Oklahoma and then the flow gets really
zonal west to east for the 18th 19th
just
all the kinks go away. That's a weird
That's a weird site.
So, we do with that trough off the west
coast, we have cooler um air out there,
but the heat remains on this side of the
Rockies with the heat center out on the
Great Plains. You see that uh some of
that's precipitation cooled in Arizona,
Utah, and some of it's just a general
cooler air under the trough, but the
heat is still there. the 9th and 10th.
We're still above normal cuz now normal
is dropping almost into the 70s and
we're still playing with upper 80s and
90s. So here's the 12th 13th west coast
cools down but doesn't push the heat
very far. It just kind of remains over
Colorado
at midmon. Now the heat expands back to
the west
and really extreme heat in the Great
Plains. We just have a little edge of it
there. We're up to the 18th 19th and
that's when the zonal flow kind of kicks
in.
You can see there's cold air to the
north and we just started the loop over
again. All right. Let's look at
precipitatable water and it never really
gets pushed away. So the heat stays and
the moisture stays throughout this time.
So it's just little ripples or little
surges of moisture that kick off extra
thunderstorm coverage on like se uh
Sunday, Monday, Wednesday,
[clears throat] next Saturday. But dry
air just the north. Wyoming's dry for a
little bit. But we are we have that
hurricane there that's dying and dumping
its moisture into the western part of
the nation. Water is very cold. So
thunderstorm thunderstorms. Yeah,
thunderstorms and a hurricane just shut
off. And it's not until about the 15th
we see some dry air in the western
slopes. Then there's a surge coming up
from the south. So you can see Arizona,
New Mexico starting to flood in towards
the four corners and then bang, we're
back into good amounts of moisture.
They're way above normal in northern
Arizona. I guess there's big flooding in
Grand Canyon with the Himalayan
flooding. Um I haven't seen any video of
what happened in Grand Canyon uh
recently.
Hey, due points are very similar story.
So I I don't think I'll park here much,
but you can see there's good deep
moisture, especially into this weekend.
We got 50s even 60 due points not far
away and into Monday another surge of
moisture. So it's going to feel humid
and you're going to see thunderstorms.
Uh pretty good coverage. So let's go
look at the thunderstorms. There's
[clears throat] a hurricane down there.
And this is into Saturday kind of dry.
And then into Sunday there's big storms
all over the eastern plains moving out.
Surge of moisture through Utah with like
a little front out there. Then we get
storms again on Tuesday. Monday, sorry.
Monday, Tuesday. Now more storms.
Western slopes get it first and then we
get some on Thursday
there. Friday is pretty good on the
western slopes. Up in the mountains, a
lot of thunderstorm activity in the
western slopes. And then Saturday comes
out again into the eastern plains.
We'll take this up to the 14th and 15th.
You can see it's really dry uh again by
midmon with that break and the
precipitatable water and dupoint and
then slowly that moisture starts coming
back up through Arizona
and kicking off in the mountains.
Sometimes only in the mountains. Here's
the 19th and 20th
and
we start over again. So, the next 5
days, spotty uh rain, but looks like
almost everybody gets a little
something. Just a few people lucky with
lots of water. Then over the next 10
days, that is a lot of rain. So, really
expecting the thunderstorm coverage to
pick up. So, we start out hot and dry
Thursday into Saturday, uh 90s. Then we
cool into the 80s, but still above
normal with pretty much a 50/50 chance
of storms every day. Week two, above
normal temperatures. September outlook,
above normal temperatures. Week two,
above normal precipitation to some
extent. And September outlook, we're
right on the edge of above normal
precipitation to 50/50. Could go either
way. This has been chief meteorologist
John Ensworth urging you to keep looking
up.