Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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
715
FXUS65 KBOU 270201
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
801 PM MDT THU MAY 26 2016

.UPDATE...
Issued at 746 PM MDT Thu May 26 2016

Upper trof across South central Colorado with main precip shield
over the Northeast plains of Colorado. Drying has been noted over
the Front range and Northern foothills as Northwest downslope flow
continues from Mountain top level and below. Have updated
forecasts/grids for lower pops especially North of Denver up to
the Wyoming border. Latest Hires models are showing this trend of
drying and will continue this trend. Will still have high pops for
much of the Northeast plains mainly east of the Interstate 25
corridor. models do show some redevelopment of precip further West
with some wrap around precip across the Low.

Will keep winter weather advisory for zone 34 but feel amounts may
be overdone. webcams do show snow falling but roadways are just
wet for now.

&&

.SHORT TERM...(This evening through Friday)
Issued at 331 PM MDT Thu May 26 2016

An upper low moving into southwestern Colorado continues to
provide good lift over the forecast area as moisture continues to
stream in on northeasterly low level flow.  A surface low over
southeastern Colorado will begin to turn surface flow northerly,
converging moisture in the easterly flow. This is already
providing good focus for the current line of storms north to south
east of the urban corridor. CAPE values around 2000 J/kg expected
over Elbert, Lincoln and Washington and 0-6km shear values between
40 and 50 kts will keep the threat of severe storms with large
hail, damaging winds and possible tornadoes continuing through
early this evening. The other concern may be localized flash
flooding with such a moist environment.

Upslope north-northeasterly flow will be increasing tonight which
will focus more precipitation over the Palmer Divide area. Also,
convergence out over the eastern plains will help focus
precipitation. As the upper low moves closer, storm motions will
become slower, increasing the flooding threat. Showers and
thunderstorms should become more stratiform tonight. Some models
have 2 to 3.5 inches across these areas through Friday. Over the
mountains, snow levels are expected to drop to between 9000 and
10000 feet. Rich moisture and upslope flow will continue to bring
accumulating snow above 10000 feet. Winter Weather Advisory will
continue for expected snow amounts and travel impacts.

Rain and high elevation snow showers will continue Friday morning
with a few thunderstorms possible as the upper low moves over
eastern Colorado. Continued northerly flow and cloud cover from
precipitation will limit much heating tomorrow. Max temperatures
are expected to stay in the 50s to low 60s. Showers should be
decreasing over the foothills and urban corridor in the afternoon
as flow starts to turn northwesterly to dry out and QG vertical
motions will turn downward.

.LONG TERM...(Friday night through Thursday)
Issued at 331 PM MDT Thu May 26 2016

Upper level low pressure system will move into the Central Plains
Friday night. Weak subsidence and drying will allow lingering
showers and storms to decrease during the evening, ending last
over the far eastern plains and in the mountains where weak
orographics could help some light showers hold into late evening.

For the Memorial Day weekend Saturday through Monday, we should
see fairly typical weather for this time of year as generally
light west/southwest flow aloft prevails. That should mean near
normal temperatures with highs in the lower to mid 70s over the
plains, and 50s/60s in the mountains.

Temperatures could turn slightly cooler with a little better
chance of rain Tuesday, as long as a cold front arrives as
expected. This front appears to be pushed southward by a short
wave trough moving across the northern U.S. The slightly cooler
weather may be replaced by warmer and drier conditions by
Thursday into next weekend if ridge builds in as advertised.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 746 PM MDT Thu May 26 2016

rainfall diminishing at kden/kapa during the past hour as winds
have shifted around to the Southwest. models do show some
redevelopment later in the night and have adjusted latest TAF to
account for this. given downslope flow may not see the lower
ceilings that were previously advertised.

&&

.HYDROLOGY...
Issued at 331 PM MDT Thu May 26 2016

Precipitable water values of 0.60 to 0.90, around the 90th
percentile, are expected to continue across the plains area
through Friday. This will allow for numerous showers and
thunderstorms to continue through the night. The stronger storms
may be able to drop an inch or two of rain, especially this
evening as slower storm motion is expected and due to possible
training of storms. The thunderstorms combined with steady
rainfall tonight may cause elevated streams and creeks to rise
more. Low lying areas susceptible to flooding could see issues.
Main area to watch is south and east of Denver where the heaviest
rain is expected.

&&

.BOU Watches/Warnings/Advisories...
Winter Weather Advisory until 9 AM MDT Friday for COZ034.

&&

$$

UPDATE...Entrekin
SHORT TERM...Kriederman
LONG TERM...Barjenbruch
AVIATION...Entrekin



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.