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087
FXUS65 KBOU 010224
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
824 PM MDT Tue Apr 30 2024

.KEY MESSAGES...

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- Isolated showers northern plains and mountains tonight

- Cooler late Wednesday into Thursday with a quick round of snow
  showers in the mountain and rain showers and thunderstorms on
  the plains.

- Another round of showers and storms late Friday/early Saturday.

- Warmer and breezy over the weekend.
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&&

.UPDATE...
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Issued at 824 PM MDT Tue Apr 30 2024

Some shallow convection has been attempting to develop across the
plains north and east of Denver. This has occurred in an area of
shallow anticyclonic upslope, weak frontogenetic forcing, and a
transition from subsidence to neutral or slightly upward QG
forcing. The mid levels have also moistened slightly per latest
ACARS soundings and water vapor imagery. Most of this should be
fairly weak given MLCAPE mostly under 200 J/kg, but perhaps a
rumble or two of thunder. We earlier added some low PoPs to the
plains north and east of Denver. Some of these should could linger
overnight into early Wednesday morning with increasing QG lift
noted. Otherwise, pretty small adjustments made for the latest T,
Td, and wind trends with the anticyclonic flow.
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&&

.SHORT TERM /Through Wednesday/...
Issued at 341 PM MDT Tue Apr 30 2024

True-Color satellite imagery shows a beautiful day across the
forecast area today with widespread sunshine. Tonight will be mild
and dry with increasing clouds through the overnight hours. Low
temperatures will stay a few degrees above normal seeing widespread
high 30s/low 40s across the foothills and plains with the mountains
staying in the high 20s/low 30s.

Overnight, westerly flow aloft will transition to the southwest by
early tomorrow morning as a shortwave trough advances eastward from
the PNW. The latest guidance indicates mid and upper level moisture
will increase throughout the day and with decent mid level lapse
rates (6-9 deg C/km), and a jet overhead in the morning, there is a
chance for some morning rain showers to develop over the northern
mountains. With mid level lapse rates remaining in the 7-8 deg C/kg
range through the afternoon across the lower elevations, there is a
chance for some rain showers or a few isolated thunderstorms to
develop in these locations. Temperatures will be well above normal
for Lincoln County reaching the high 70s, and closer to the norm for
the rest of the plains and foothills reaching 60s and 70s.

&&

.LONG TERM /Wednesday night through Tuesday/...
Issued at 341 PM MDT Tue Apr 30 2024

It still looks like there`s a pretty good chance of getting
a brief round of showers/storms Wednesday evening as there`s some
instability. Not much of a severe threat, although there may be as
much as 1000 J/kg of CAPE in the northeast corner in the early
evening. There`s quick drying behind the trough, so the threat of
showers and probably clouds will be gone by morning. There may be
enough moisture left for isolated diurnal convection Thursday
afternoon, but it may just be too dry. We may be briefly close to
critical fire weather conditions.

The next shortwave still looks like it comes late Friday, probably
well timed for another quick round of showers/storms helped by an
afternoon cold front.

The weekend looks dry and warm under a shortwave ridge Saturday,
and then southwest flow ahead of a west coast trough for Sunday.
Our forecast remains on the warm side of the ensemble envelope,
which is probably alright and near the operational runs. We could
have critical or near critical fire weather ahead of the trough,
though greenup is limiting fire danger now. The trough probably
brings another quick round of showers/storms as it comes by
quickly and possibly north of us. Scattered PoPs Monday and slight
cooling Tuesday in the NBM look good.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 543 PM MDT Tue Apr 30 2024

VFR conditions will persist through the TAF period. Winds will be
the main concern, but for now it appears easterly winds (with
gusts to around 20 knots) will dominate through about 06Z before
trending more southeasterly overnight. There could be a period of
stronger south/southwest winds toward 17Z-21Z Wednesday with
gusts up to 20-28 knots...depending on how fast we heat up and
mix, but somewhat lighter south/southeast winds (40-50% chance)
could also prevail. The southerly component wind is expected to
last until a cold front arrives toward 21Z, turning winds more
from the north/northwest and increasing with gusts up to 30 kts.
We`ll also see growing chances of showers behind the front. The
most likely time for showers and IMC would be after 00Z tomorrow
evening, so covered that with a TEMPO group. Only isolated
thunderstorm possible (10%).

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Barjenbruch
SHORT TERM...Bonner
LONG TERM...Gimmestad
AVIATION...Barjenbruch