405
FXUS65 KBOU 021128
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
528 AM MDT Thu May 2 2024

.KEY MESSAGES...

- Isolated weak showers late this afternoon and evening over the
  plains, with a slight chance for thunderstorms.

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

- Warmer and breezy over the weekend.

&&

.SHORT TERM /Through tonight/...
Issued at 333 AM MDT Thu May 2 2024

Westerly flow aloft will prevail across Colorado today and
tonight. A subtle ridge embedded in the westerly flow will cross
Colorado today. The westerly flow aloft will produce gusty west to
northwest winds over the mountains, foothill, and far northern
Colorado. Surface high pressure also slides over the region. Anti-
cyclonic flow is expected to produce east to southeast across the
Denver area and the nearby plains. Expect mostly sunny skies
through early afternoon due to the ridging and surface high.
Clouds increase late this afternoon and evening as the ridging
slides off to the east. The right entrance of the jet will provide
lift for the clouds and also for few weak showers over the
eastern plains late this afternoon through tonight. A brief
thunderstorm, can`t be ruled out as well. Cooler air behind
yesterday`s cold front will cause temperatures take a step
backwards today. Highs over northeast Colorado are expected to top
out in the lower 60s.

&&

.LONG TERM /Friday through Wednesday/...
Issued at 333 AM MDT Thu May 2 2024

Strong southwesterly flow and mid-level moisture increases Friday
as the next shortwave trough enters our region. A few favorable
conditions such as QG lift, steep lapse rates near 7-8 C/km, and
MLCAPE values between 500-700 J/kg will allow for scattered
thunderstorm development for areas mainly east of I-25 corridor
Friday afternoon. These storms located near the Kansas/Colorado
border have the best chance of becoming severe. If this occurs,
storms would likely produce hail and wind gusts up to 50-60 mph.
This outcome could occur in the small window just before the front
arrives sometime between late afternoon to early evening Friday.
As the front enters our CWA, wind gusts up to 40 mph could occur
across the plains. With snow level roughly near 8k ft, higher
elevations especially along the Park Range could accumulate snow
up to 1-4 inches through Saturday morning.

This weekend, ample amounts of drier air can be seen along cross
sections indicating a short-lived ridge pattern replaces our
shortwave trough. Afternoon temperatures increase especially
Sunday. Mountains and valleys increase near the low 50s to 60s.
Foothills and plains should reach the mid 60s to mid 70s. There is
a lack of QPF for the lower elevations thus if any storm were to
develop Sunday, it will likely be isolated near the northeast
corner with the potential for severe hail/wind. Steeper pressure
gradients are likely starting Sunday as our short-lived ridge
exits and a mid- level low enters northeastern Colorado. Expect
southwesterly flow to increase resulting in widespread wind gusts
up to 45 mph.

There is a bit more agreement on the placement of the trough axis
arriving Monday through Tuesday in southeastern Wyoming. Westerly
winds align with an upper level jet favoring strong cross barrier
flow. This could lead to strong downslope winds for the lower
elevations both Monday and Tuesday afternoon. Ensembles favor light
QPF amounts and with temperatures increasing, this may lead to rain
showers for the mountain valleys. For PoPs, the GFS/ECMWF differ in
how much moisture arrives east of the Divide. For now, following
NBM guidance. Either way, prepare for gusty conditions next week.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 528 AM MDT Thu May 2 2024

VFR to prevail through tonight and into Friday morning. Gusty
northwest winds over far northeast Colorado will produce anti-
cyclonic flow over the Denver area, resulting in east to southeast
winds for the Denver airports. The HRRR model seems to be over
mixing the flow aloft with the model showing gusty west winds this
afternoon. Most of the other models show east/southeast winds
which seems on track under this pattern. For late tonight and
Friday morning, winds turn southerly and increase ahead of a cold
that pushes through after 18Z Friday.

&&

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

&&

$$

SHORT TERM...Meier
LONG TERM...AD
AVIATION...Meier

NWS BOU Office Area Forecast Discussion