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Area Forecast Discussion (AFD)

Issued by Denver/Boulder, CO (BOU)

FXUS65 KBOU 181610

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1010 AM MDT Sun Aug 18 2019

Issued at 1010 AM MDT Sun Aug 18 2019

GOES-16 imagery currently is showing a good erosion of the 
stratus deck from south to north. The clouds will be out of the 
Denver metro area shortly, burning off last from Boulder north and
northeastto the Loveland-Greeley-Fort Collins metro area where 
upslope is strongest for now. Expect the clouds to dissipate by 
midday across Larimer/Weld counties. The clouds have cooled the 
rate of warming so far this morning and normally we'd be concerned
that the high temperatures in the 90s across the metro area 
wouldn't be reached. However, the 12Z KDNR sounding shows just how
shallow the cool air is, and with 700 mb temps warming to +17degC
this afternoon, the 90s should have no problem being reached. The
high res guidance wants to go into the 93-95 range for Denver. 
Not going that high, but we should reach the 90s most areas across
the I-25 corridor. Temperatures overall not as warm aloft nor 
near the surface for the NE corner, so low to mid 80s still look 
okay out there. Near 0 chance of precipitation anywhere today, so 
other that adjusting sky grids for the stratus, no changes were 
made to today's forecast.


.SHORT TERM...(Today and tonight)
Issued at 213 AM MDT Sun Aug 18 2019

Upper level high pressure will be building over the Southern and 
Central Rockies today with a weakening westerly flow aloft over 
Colorado. A cold front is currently moving south across northeastern 
Colorado and is now moving into Metro Denver. Low clouds and areas 
of fog will continue to spread south across much of the plains
and linger through about mid morning. Mostly sunny skies are 
expected by afternoon with temperatures around 10 degrees cooler 
across the far northeastern plains. However, areas along the 
Front Range Urban Corridor should only see slight cooling behind 
the front. The combination of upper level high pressure building 
over the region and the stable airmass behind the front will bring
dry weather to all of north central and northeastern Colorado 
through tonight. Mild temperatures are expected tonight with low 
clouds and areas of fog developing over the plains east of Denver 
after midnight.

.LONG TERM...(Monday through Saturday)
Issued at 213 AM MDT Sun Aug 18 2019

Monday will be hot and dry with highs over the plains in the mid 
to upper 90s. Record high at Denver is 97 which could be tied or 
broken. Over the far eastern plains capes will exceed 3000 j/kg, 
however, soundings show a capping inversion around 650 mb. Thus 
if any storms develop they will be isolated early Monday evening.

For Tue, an upper level ridge will remain over the area. The 
ECMWF shows some subtropical moisture advecting north northeast 
into the area by aftn. Thus can't rule out some widely sct higher 
based storms over the higher terrain and plains. As for highs, 
temps will remain in the 90s over nern CO. By Tue night a cool 
front will move across the plains. There also could be a weak 
disturbance that may affect nrn CO as well. As a result there may
be a better chc of storms over portions of nern CO. The ECMWF 
continues to focus the best chc of storms over the far nern 

On Wed, the upper level ridge will weaken a bit as weak upslope flow 
is in place over nern CO.  There will still be some influx of 
subtropical moisture over the area with weak flow aloft.  Overall 
should see a good chc of storms over the higher terrain and over 
nern CO.  Temperatures will be cooler as well with readings ranging 
from the upper 70s to mid 80s over the plains.

By Thu, weak west to northwest flow aloft will be over the area, 
as south to southeast low level flow develops across the plains. 
Overall should see a chc of storms over the higher terrain and 
along the front range. Temperatures will be near seasonal 

For Fri, an upper level high will build from the Great Basin into 
Colorado with a drier airmass developing over the area.  Thus will 
see a decreasing chc of storms with above normal temperatures. 


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1010 AM MDT Sun Aug 18 2019

CIGs have recently improved DEN and APA, scattering out and
dissipating entirely as the stratus deck erodes from south to 
north. BJC will be very soon, expecting it to clear out in about 
30 minutes. We do not expect a repeat tonight/early tomorrow of a
stratus deck and thus it will be VFR through Monday. Convection 
across the high plains/central plains should be weaker to non- 
existent such that no outflow boundaries are expected this 
afternoon. Light northeast winds expected this afternoon turning 
to southeast then drainage around midnight. On Monday no chance of
convection impacting the terminals and very low chance of outflow
winds making an impact either. Just hot and dry with weak north 
to northeast winds throughout the afternoon at DEN and APA, 
probably northwest at BJC.


Issued at 213 AM MDT Sun Aug 18 2019

Fire danger will continue to be elevated in the mountains and 
foothills today due to low relative humidity and westerly winds 
gusting up to 25 mph.

On Monday fire danger will remain elevated over much of the area
due to low humidity and above normal temperatures.