Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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513
FXUS65 KBOU 221816
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1216 PM MDT FRI JUL 22 2016

.UPDATE...
Issued at 1216 PM MDT Fri Jul 22 2016

Some subtle changes may be inhibiting convection this afternoon.
There has been some drier air spreading off the mountains dropping
dew points into the 40s. Further east the low level moisture is
still there, but while the models are trying to redevelop
southerly flow over eastern Colorado this afternoon it looks like
this will either be slower to develop, or further east in western
Kansas. In addition, there is a slight warming in the 400-500 mb
layer spreading across our area from the west. This is not enough
to completely cap convection over the western part of the area,
but it will further reduce the CAPE. Still expecting quite a bit
of convection to develop, but it will generally be weak and over
the mountains much of it could be fairly shallow as well. I have
trimmed POPs a bit, but the biggest difference is just that there
is not much of a chance of severe weather or flooding today. Could
be an outside chance of a localized severe gust or a short period
of heavy rain with the strongest cells, but in general the energy
is just not there.

&&

.SHORT TERM...(Today and tonight)
Issued at 320 AM MDT Fri Jul 22 2016

Overall synoptic pattern has not changed much although expect the
broad upper high to retrograde further West into New Mexico today.
Water vapor imagery showing Colorado will remain under the plume
of deeper moisture with PW values hovering just over an inch.
Deeper moisture now over Arizona expected to increase moisture
even more over Colorado this afternoon and evening under the
steering Southwest flow aloft. Model forecasts and soundings
showing PW values will range from 1.10 to 1.25 inches by later
today over the plains. Forecast models more ambitious with QPF
generation over the plains this afternoon and evening with focus
over North Central mountains and extending out over the Palmer
Divide. As in previous days, Northern Front range looks drier.  With
a bit more cloud cover and slightly earlier convective development,
temperatures may be 1-2 degrees cooler from yesterday`s readings.
Main threat again will be heavy rain and gusty outflow winds with
the stronger storms. severe threat is low again today with only
modest CAPE/shear values.

As in previous days, showers and storms will gradually diminish
later this evening and overnight over the plains. Lingering cloud
cover will likely keep overnight low rather mild again.

.LONG TERM...(Saturday through Thursday)
Issued at 225 AM MDT Fri Jul 22 2016

The upper level high will weaken some on Sat but then strengthen
over the cntrl and srn Rockies for Sun into Mon.  Moisture will
decrease a bit on Sat with the best instability in the mtns.  Over
the plains a prefrontal wind shift by midday will scour out the low
level moisture with limited cape over the plains.  Thus will keep
the highest pops over the higher terrain in the aftn with only isold
pops along the front range urban corridor. During the evening hours
low lvl moisture may gradually increase over the Palmer Divide
which may lead to an increase in tstm activity. As for highs it
will remain hot across nern CO with another day of 90s.

On Sun a cool fnt will move across nern CO in the morning with ely
flow by aftn.  However models are not in agreement on low lvl
moisture fields across nern CO by aftn into the evening hours.  The
NAM and GFS keep the best low lvl moisture fm the srn Foothills
across the Palmer Divide while the ECMWF has this moisture further
north across the nern plains.  As a result the NAM and GFS keep the
best chc of storms fm the srn Foothills across the Palmer Divide
while the ECMWF has better chances further north.  For now will
keep best chances further south like NAM and GFS show.  Over the
higher terrain here will still be a chc of storms especially along
and south of I-70.  As for highs readings across nern CO will cool
slightly into the upper 80s to lower 90s.

By Monday the upper level high will be centered over CO and NM with
a continuation of subtropical moisture flowing across the area. Thus
will see a chc of storms over the higher terrain.  Over nern CO will
see at least a slight chc of aftn and evening storms.  850-700 mb
temps rise a few degrees on Mon so aftn highs may rise back into
the lower to mid 90s across the plains.

For Tue into Wed the upper level high is fcst to gradually
retrograde westward into the Great Basin.  Appears there will still
be some influx of subtropical moisture on Tue but it may begin to
shift westward by Wed.  Thus will probably see a decrease in tstm
activity over the higher terrain especially on Wed.  Across nern CO
will keep in a slight chc for storms on Tue and Wed.  As for highs
readings will stay in the lower to mid 90s.

By Thu the upper level high will be centered over the Great Basin
with wnw flow aloft across nrn CO.  The ECMWF has a weak fnt moving
into nern CO during the day while the GFS does not.  This far out
hard to say which will end up being right.  For now will just
mention a slight chc of storms and keeep highs over nern CO in the
lower to mid 90s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1216 PM MDT Fri Jul 22 2016

VFR through tonight. Scattered showers and thunderstorms are
expected in the Denver area between 21z and 02z. Main impact is a
chance of gusty outflow winds gusting to 30 knots.

&&

.BOU Watches/Warnings/Advisories...
None.
&&

$$

UPDATE...Gimmestad
SHORT TERM...Entrekin
LONG TERM...RPK
AVIATION...Gimmestad



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