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709
FXUS65 KPUB 010940
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
340 AM MDT Wed May 1 2024

.KEY MESSAGES...

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- Critical fire weather conditions for the San Luis Valley and
  portions of the southeastern plains today.

- Isolated thunderstorms possible this afternoon and early
  evening over the central mountains, the Palmer Divide and the
  far eastern plains. One or two strong thunderstorms possible
  across Kiowa, Bent and Prowers counties.

- Critical fire weather conditions possible for the San Luis Valley
  Thursday and Friday.

- Isolated to scattered showers and thunderstorms possible through the
  rest of the work week into the weekend.
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&&

.SHORT TERM /THROUGH THURSDAY/...
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Issued at 336 AM MDT Wed May 1 2024

Currently...Cold front last evening has produced easterly winds
across the eastern plains, while winds aloft remain brisk and out of
the west to southwest in response to an upper low pressure system
moving across the northern Rockies. Temps as of 3 AM have cooled
into the 30s to lower 40s for the high valleys, and 40s for the
plains.

Today and tonight... A lot going on today as an upper trough slowly
crosses MT and WY over the next 24 hours. Increasing west-southwest
flow aloft will advect warmer and dry air into much of the forecast
area today, though the central mts and northward will likely see
some enhanced cloud cover and isolated convection by the afternoon.
The central mts may see 1 to 3 inches of new snow through tonight,
mainly across the higher peaks of Lake County.

Convection/thunderstorm potential:  As the upper trough gradually
moves east, the best dynamics will remain over the northern half of
CO, clipping the central mts starting by midday, then sweeping east
across Teller County and the Palmer Divide by mid-afternoon. Plenty
of solar heating today will help a surface low to deepen over
southeastern CO, and the question will be where exactly the dryline
sets up. Some models indicate it quickly pushes into KS, while
others have it linger for a few hrs in eastern CO before pushing
east. Given the expected brisk southerly surface winds across the
far eastern plains, coupled with an approaching cold front early
evening, feel that there will be a window of opportunity out ahead
of the front for a strong storm or two to tap into higher dewpoints
across Kiowa, Bent and Prowers counties this afternoon between 3 PM
and 9 PM. There will be plenty of shear, 0-6km bulk shear of 55-65
kts, and CAPE sitting at around 1000 j/kg. The actual time window
will likely be smaller, depending on the arrival of the cold front
which is timed in the forecast to push south across the Palmer
Divide right around 8 PM. The main threats from storms that do
develop will be gusts up to 55 mph and hail to the size of nickels.

Critical fire weather potential: Further south, feel that with the
low humidity levels and expected gusty winds developing during the
afternoon, the current Red Flag Warning in place for the San Luis
Valley and portions of the southeast plains looks good. The only
questionable area will be Baca County, where the dryline will be
flitting across and could negate the dryness criteria.

Activity dies off quickly for much of the area by midnight, with
much of the action pushing east into the central US plains, and just
isolated showers lingering over the central mts.

Plan on high temps today in the mid 60s to mid 70s for the high
valleys, and upper 60s to around 80F for the plains. Overnight lows
tonight will cool into the 30s for the high valleys, and 40s for the
plains. Moore
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&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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Issued at 336 AM MDT Wed May 1 2024

Moderate to strong west to southwest flow aloft continues across the
region Thursday and Friday, with one embedded shortwave translating
east into the Northern High Plains early Thursday morning, as another
embedded wave remains progged to translate across the Northern Rockies
through the day Friday, which continues out across the Northern High
Plains late Friday night. A cold front associated with the 1st passing
wave backs across the southeast Plains early Thursday morning, with the
potential for some patchy early morning stratus across the lower eastern
slopes. Latest models indicate drier mixing across the region through the
day Thursday, though with steep mid level lapse rates and easterly low
level upslope flow, will see isolated to scattered high based showers and
a few possible storms across the higher terrain, with best coverage across
the Pikes Peak region. Further west, breezy westerly flow aloft and afternoon
mixing develops critical fire weather conditions across the San Luis Valley,
where a Fire Weather Watch has been issued for Tuesday afternoon into the
early evening.

Latest model data indicates increasing southwest flow aloft across the
Rockies ahead of the next embedded wave Thursday night, with developing mid
level waa supporting chances of showers across the southeast Plains through
the overnight hours. Developing lee troughing across the Plains allows for
breezy southerly winds across the plains through the day Friday, with
increasing low level moisture east of the trough support chances of afternoon
showers and storms across the Plains Friday afternoon, while uvv associated
with the passing wave supporting scattered showers and storms spreading across
the higher terrain Friday afternoon and out across the Plains Friday night,
as the passing systems cold front pushes across the plains into early Saturday
morning. Breezy west to southwest winds across the San Luis Valley through the
day Friday, will again support critical fire weather conditions for the Valley
and possibly into portions of the I-25 Friday afternoon and early evening.

Shortwave ridging builds across the Rockies on Saturday, with enough moisture
combined with low level upslope behind this front will help to develop a few
showers and storms across the eastern mtns and immediate adjacent plains
Saturday afternoon.

Latest model data coming into slightly better agreement for Sunday and into
early next week, as a strong upper low translates across Great Basin Sunday
and then lifts out across the Northern Rockies Monday. Strong southwest flow
across the region Sunday could develop a dryline across the Plains Sunday
afternoon, with chances of showers and storms across the far southeast Plains
Sunday afternoon and evening. Dry, warm and breezy westerly flow then looks
to prevail across the Rockies Monday into the middle of the work week, with
fire weather concerns continuing across the region.
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&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
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Issued at 336 AM MDT Wed May 1 2024

An upper low pressure system passing by to the north will bring
deteriorating conditions for the northern half of the state today,
which will clip the central mts. MVFR to IFR conditions expected to
develop due to snow and lowering cigs over mt passes of the central
mts after 18z-20z and continue into the evening.

Elsewhere, much of the forecast area is expected to enjoy VFR
conditions over the next 24 hrs, including the three main TAF sites
of KCOS, KPUB and KALS. A cold front is forecast to push south
across the Palmer Divide between 00z and 02z, affecting KCOS
and KPUB but pcpn is not anticipated at terminals. Further east
across the plains, stronger storm activity may occur, especially
near /KS border.

KCOS and KPUB: Increasing S-SE winds with gusts to 25 kts between
18z and 02z. Cold front passage roughly 01z at KCOS and 03z at KPUB
will swing winds around to the north with gusts to 25-30 kts and
lowering cigs towards the end of the forecast period.

KALS: Increasing W-SW winds with gusts 30-35 kts developing between
17z and 02z.
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&&

.PUB WATCHES/WARNINGS/ADVISORIES...
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Red Flag Warning from noon today to 9 PM MDT this evening for
COZ224-232-233-237.
Fire Weather Watch from Thursday afternoon through Thursday
evening for COZ224.
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&&

$$

SHORT TERM...MOORE
LONG TERM...MW
AVIATION...MOORE