FXUS65 KPUB 232129

Area Forecast Discussion
National Weather Service Pueblo CO
329 PM MDT Tue Jul 23 2019

.SHORT TERM...(This evening through Wednesday)
Issued at 243 PM MDT Tue Jul 23 2019

Mountain storms so far this afternoon a little less widespread than
the past couple days, as precipitable water has drifted downward
slightly. Nly steering flow also keeping storms fairly close to the
higher terrain with storms drifting south or a little southwest so
far. Expect storm coverage to increase slightly this evening as weak
upper wave dives south over the ridge, with HRRR and various
iterations of the NAM suggesting fairly widespread activity over the
eastern mountains until 03z-05z. Given CAPE of 1k-2k J/KG pooling
along eastern mountain slopes, localized strong storms and heavy
rainfall look likely, with flash flood threat continuing in/near
local burn scars. While nly flow aloft will tend to keep most
activity west of the I-25 corridor into this evening, late arrival
of upper forcing from short wave trough may provide just enough lift
to spark a few storms east of the mountains after 00z, especially El
Paso/Pueblo Counties. Most activity then fades overnight, though a
few showers could persist near the Continental Divide into Wed
morning as mid level moisture lingers.

On Wednesday, little change in the pattern with upper level ridge
along the CO/UT border and plentiful moisture remaining in place
across the region. Expect another round of afternoon storms over the
mountains, with convection slowly drifting south under very light
nly steering flow. Most activity will stay along and west of I-25,
though a few weakening cells may drift toward lower elevations late
in the day. Main risk again will be heavy rain/burn scar flash
flooding, with models hinting that areas back toward the Continental
Divide may see the strongest storms. Lee surface trough on the
plains may induce some weak downslope flow in the afternoon, which
will boost max temps a few degf east of the mountains versus

.LONG TERM...(Wednesday night through Tuesday)
Issued at 243 PM MDT Tue Jul 23 2019

Overall the operational solutions are in decent agreement through
the extended period. Ensembles have relatively small spreads
through much of the period, with some differences in the upper
level high pressure that is forecast to build across the region.
Overall, forecast confidence is on the higher side.

Wednesday night through Friday...high pressure is forecast to be
centered over the Four Corners region through Thursday before it
retrogrades into southern California on Friday. This will keep the
potential for showers and thunderstorms across the region. Expect
ongoing mountain thunderstorms Wednesday evening with northwest
steering flow pushing the activity south and east. Locally heavy
rainfall and lightning will be the primary threats, but a few
stronger cells could produce gusty outflow winds and small hail.
This activity will dissipate after sunset and dry conditions will
likely prevail across the region by Thursday morning. Across the
Plains, an area of low pressure is forecast to move east with a
cold front dropping south into the I-25 corridor by morning.

For Thursday, expect another round of afternoon and evening
showers and thunderstorms across the region. Initial development
will once again be over the mountains. Weak northwesterly steering
flow should help push storms east into the I-25 corridor and
points east, before dissipating overnight. Low level flow will
likely be more upslope with abundant moisture across the region.
This will lead to locally heavy rainfall and flash flooding may be
possible on area burn scars and urban areas. In addition, small
hail, lightning and gusty outflow winds will be possible.

By Friday, the upper level ridge is forecast to retrograde
southwest into southern California. Drier conditions are expected
across the region. That being said, isolated to scattered
convection is anticipated. Locally heavy rainfall will once again
be possible with stronger storms.

Saturday and Sunday...an upper level disturbance is forecast to
track across the northern Rockies over the weekend. Expect better
chances for showers and thunderstorms on Saturday, especially over
the mountains. A cold front will arrive by Sunday morning with low
level moist flow turning upslope across the region. Sunday may be
the day for the greatest flash flood potential, especially over
burn scars. This will need to be monitored.

Monday into Tuesday...the upper level high is forecast to progress
back across the Four Corners region early next week. This will
bring a return to hot temperatures. Current model solutions are
dry, but isolated to scattered showers and thunderstorms will
continue to be possible, especially across the higher elevations.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 243 PM MDT Tue Jul 23 2019

Storms developing over the mountains this afternoon will gradually
spread to lower elevations into this evening.  Will carry a vcts
mention at all sites from 22z-03z, with lowest chance of a tsra at
KPUB, as steering currents will tend to keep storms closer to the
high terrain. Strongest storms will again produce briefly gusty
winds 40 kts and low visibility due to heavy rain. Convection ends
03z-06z, with clearing skies and VFR conditions overnight. Similar
pattern on Wed, with mainly mountain storms in the afternoon.





NWS PUB Office Area Forecast Discussion