936
FXUS65 KBOU 301026
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
426 AM MDT Thu May 30 2024

.KEY MESSAGES...

- Scattered afternoon showers and thunderstorms today and Friday.
  A few could be severe across the plains, and even portions of
  the I-25 Corridor for Friday.

- Warmer and drier beginning Saturday, but a couple strong to
  severe storms still possible on the plains.

- Hottest temperatures of the year so far Sunday into early next
  week.

&&

.SHORT TERM /Through tonight/...
Issued at 425 AM MDT Thu May 30 2024

A weak cold front will drop across the northeast plains this
morning. A preliminary ripple came down into Denver, but a deeper
surge of north winds will come by mid morning. This will result in
some stabilization of the atmosphere across most of our area
today, and some drying aloft will help as well as deep mixing
occurs later today. For the most part, we`re expecting weak
convection without much precipitation over the northern and
western parts of our area most of the afternoon, maybe nothing in
the northern half. A little cooling around 700 mb along with some
moistening at the surface should bring an increase in convection
and scattered thunderstorms late in the day. Further south,
generally south of I-70 on the plains, there will be a bit more
instability as there should be less cooling and drying. So the
storms may form a bit earlier there and be stronger. There may
still be CAPEs up to 1000 J/kg in Lincoln county with a small
severe threat, mainly hail.

With fairly light winds aloft, whatever convection we get could be
slow to move east, and there will be moist surface winds providing
convergence to keep them going. So we`ll have PoPs over the
eastern part of the plains into the early morning hours. There`s
another surge of north to northwest winds late tonight along with
some QG lift from a better shortwave trough passing north of us.
Models vary on the strength of the surface boundary and whether
there will be a band of showers or thunderstorms with it. But this
threat is mainly over the northeast corner. If this feature is
strong enough and generates a decent batch of showers, it could
produce an area of stratus that pushes back to Denver at the end
of the night.

Only minor adjustments to forecast temperatures, the previous
forecast looks pretty good and is near guidance with highs about 5
degrees cooler today.

&&

.LONG TERM /Friday through Wednesday/...
Issued at 425 AM MDT Thu May 30 2024

Moist easterly low level flow combined with moderate flow aloft
and steep mid level lapse rates will bring a greater threat of
severe storms on Friday. However, that will be conditional on
whether or not we see enough surface heating and breaking of the
cap. The low levels will also be initially cool and areas of
stratus across the plains Friday morning. That will likely delay
the destabilization, but there is some broad scale lift in the
form of QG and right rear entrance region of a jet max to our
north that would potentially weaken the cap. Ingredients would be
favorable for a few severe storms late in the afternoon and
evening, including MLCAPE of 1200-1800 J/kg with mid 70s/~50 T/Td,
and 0-6km bulk shear of 40+ kts. Given the surface pressure
pattern, we believe the low level moisture actually has a decent
chance of holding in the I-25 Corridor, so the threat of a couple
severe storms could be as far west as Denver and Fort Collins.
Again, that`s dependent on stratus and surface heating, so
unfortunately we may not have any "clearer" answers until
tomorrow.

Moving onto Saturday, we`ll start to see flat ridging arrive,
leading to the beginning of true summer warmth. We are expected
to dry out along the Front Range with less and only high based
convection, while a dryline/lee trough pushes east across the
plains. A couple strong to severe storms will be possible east of
the dryline - right now we think that would mainly be along/east
of a Sterling to Limon line.

Sunday will bring on full summer warmth, with high temperatures
likely reaching 90F over most of the plains and I-25 Corridor.
There is now very good agreement in ensembles regarding this heat
and drier weather, which will likely last through at least
Tuesday. Ensemble averages only nudge down slightly (1-3 degrees
on average) toward the end of next week, but overall summer
warmth appears to be here to stay.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 425 AM MDT Thu May 30 2024

VFR through tonight. North to northeast winds will develop in the
12z-15z time range. Scattered thunderstorms are expected 20z-02z
with a couple of wind shifts with gusts to 30 knots the most
likely impact.

&&

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

&&

$$

SHORT TERM...Gimmestad
LONG TERM...Barjenbruch
AVIATION...Gimmestad