Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus65 kbou 160928 

Area forecast discussion
National Weather Service Denver/Boulder Colorado
328 am MDT Tue Jul 16 2019

Short term...(today and tonight)
issued at 243 am MDT Tue Jul 16 2019

An upper trough over the western US coast will push inland and
into the northern rockies down into the Great Basin throughout
today. This will turn flow aloft from westerly to southwesterly,
continuing the warming trend. Drier air visible on water vapor
imagery is pushing into northeastern Colorado, which is expected
to drop precipitable water values by 0.2 to 0.4 inches over
yesterday's readings. This will result in another day of
convection firing off the higher terrain just after noon, then
spreading east over the plains. The difference will be that the
storms have a lower potential to produce localized flooding due to
less moisture available and they'll be be moving quicker due to
faster winds aloft. With a jet over northern state border, higher
shear will exist over this area and will give a better chance for
stronger storms including a higher chance for hail, possibly up
to an inch in diameter. A marginal risk for severe storms is in
effect for an area northeast of a line from Cheyenne to Fort
Morgan to Akron, where cape values of over 2000 j/kg are expected
to exist.

Storms should exit out east by midnight with clearing skies. A
surface trough will be deepening across the eastern plains to help
increase westerly winds in the high terrain and foothills,
downsloping into the urban corridor. This will result in warm
overnight lows.

Long term...(wednesday through monday)
issued at 243 am MDT Tue Jul 16 2019

Main trend through Friday will be warmer and drier,
especially Thursday and Friday with temperatures approaching 100
degrees on the plains and the potential for record setting

Initially for Wednesday, the high pressure ridge will remain
anchored across much of the southern High Plains with southwest flow
across Colorado. There will be drier air beginning to work its way
through mountains and Front Range but still some lingering moisture
still on the northeast plains. This will continue a slight chance
for thunderstorms mainly over higher terrain and eastern plains.

There will be a stronger westerly flow moving across much of the
western U.S. And Colorado for Thursday and Friday and this will
bring in much drier air to the region. There is also a strong 120kt
upper jet which will be draped across the northern rockies
through the end of the week. This dry, westerly flow will keep a
downslope component to the Lee of The Rockies and result in
warming temperatures and dry conditions. 700mb temperatures will
approach the +20c mark which will push high temperatures in the
upper 90s to around 100 degrees for Thursday and especially on
Friday. Strong mid level inversion will keep thunderstorm activity
capped for both days.

The hot and dry conditions will also result in an increase in fire
danger with low humidities and some gusty winds in the mountains and
nearby plains, especially on Wednesday. At this time land
managers have reported fuel status in the mountains on the low
side for any rapid fire growth.

Some relief is expected over the weekend as a strong upper trof
moves over the northern Rocky Mountain region and swings a cold
front into northern Colorado late Saturday or early Sunday. This
will result in cooler temperatures and a better chance for
thunderstorms by late Saturday afternoon and potentially into
Sunday. Once the northern trof swings through, high pressure will
rebuild into the 4 corners and western Colorado region early next
week. Should be enough moisture under the ridge for a chance of
late day storms and seasonable temperatures.


Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 243 am MDT Tue Jul 16 2019

Southerly drainage winds early this morning will trend to the
southwest through mid-morning before backing to the southeast
early in the afternoon. Another round of thunderstorms and
showers containing gusty outflow winds can be expected again near
20z. These are expected to push east by 00z and will likely push
outflow out of the east back to the airports, before the winds
become drainage again by midnight.


Bou watches/warnings/advisories...


National Weather Service Glossary of Abbreviations