Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS65 KBOU 191529

Area Forecast Discussion
National Weather Service Denver/Boulder CO
929 AM MDT THU MAY 19 2016

Issued at 914 AM MDT Thu May 19 2016

Currently...fog that developed west of I-25 and around I-70 east
over portions of central and southern Lincoln county will continue
to raise into a low ceiling and dissipate over the next hour.
Clouds over the mountains are showing increased development on
cameras and satellite as destabilizing continues.

Later today...CAPE values on short term models are showing 750+j/kg
by 18z today over the higher elevations where thunderstorms will
develop by the afternoon. Upper air soundings indicate strong
lapse rates in the mountains with a chance for rain and possible
small hail. Cross sections wet bulb zero levels hover around
10,000 ft where a mixture of rain and snow is possible with the
storms by late afternoon. On the plains HRRR still showing highs
in the lower 70s with a convective temperature around 65. This
will help with development but LCL levels are high with most of
the plains under a cap. Some development into isolated storms will
be possible over the foothills with a stray storm moving east
over the plains.


.SHORT TERM...(Today and tonight)
Issued at 318 AM MDT Thu May 19 2016

Current satellite pictures are showing minimal cloudiness over
the mountains right now and they are on the decrease. With a weak
pressure gradient in place, the low level winds are draining
nicely. Models have an upper ridge move into Colorado today and
tonight. The flow aloft is weak and northerly early today, then
westerly by tonight. The QG Omega fields show benign synoptic
scale energy for the CWA today and tonight. The boundary layer
winds will be southeasterly today, then southerly tonight. For
moisture, models have some, especially this afternoon and evening.
The NAM keeps more in over the mountains tonight than the GFS
does. Precipitable water values are in the 0.35 to 0.75 inch range
for the first two periods. There is some CAPE, especially over the
mountains and foothills, mainly from 18z to 06z. Along the divide
there are some 1000j/kg areas noted. Lapse rates are fairly steep
in the 700-400 mb layer over the western two thirds of the CWA
this afternoon and evening. The QPF fields have minor amounts of
measurable precipitation for the western two-thirds of the CWA
this afternoon and evening. For pops...will go with "Chance"s
over the high country...and "Slight Chance"s for the western half
of the plains. For temperatures, today`s highs should be 2-5 C
warmer then Wednesday`s readings.

.LONG TERM...(Friday through Wednesday)
Issued at 318 AM MDT Thu May 19 2016

On Friday, upper level ridge axis will amplify over eastern
Colorado. Thermal ridge will spread across the Front Range
resulting in warm temperatures and highs reaching 80F or more
across the plains. In the mountains, strong surface heating and
enough moisture will result in isolated to scattered afternoon and
evening storm coverage. A couple of these will either drift off
the foothills or produce enough convergence along an outflow
boundary to bring a lot threat of storms down into lower
elevations, favoring the Palmer Divide area. Farther northeast on
the plains, low level moisture and CAPE will be higher but airmass
will remain capped off due to warmer mid levels. Similar
conditions can be expected Saturday although temperatures will
warm a couple more degrees into the lower to mid 80s with
stronger downslope component. The further warming may result in a
weakening cap so will have to watch for potential isolated severe
storms over the far northern and eastern plains.

By Sunday, the next trough will likely begin to affect the area
with slightly cooler temperatures and a better chance of showers
and storms. If moisture can hold over the northeast plains and not
get scoured east we could see a threat of stronger or severe
storms over portions of the eastern plains.

For the Monday through Wednesday period, it appears we`ll be
getting into a west/southwest flow aloft with a few embedded short
waves moving through. Overall, see temperatures returning to
closer to normal with the chance of showers and storms near
climatological levels. It will be difficult to time the
individual short waves this far out.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 914 AM MDT Thu May 19 2016

VFR conditions will prevail for the next 24 hours with
thunderstorms forming in the vicinity of the airports. APA and DEN
will see vicinity storms with some increased winds at APA. BJC
will have some possible convection on station between 22 and 01z
as some storms develop and move east off the plains. Winds will
predominately be from the SSE before going to drainage by the


.BOU Watches/Warnings/Advisories...


LONG TERM...Barjenbruch
AVIATION...Bowen is the U.S. government's official web portal to all federal, state and local government web resources and services.