Area forecast discussion
National Weather Service Denver/Boulder Colorado
853 PM MDT Monday may 20 2013
Update...showers and winds are gradually decreasing...and this
will be the trend through the rest of the evening. Only showers
that remain are generally along/south of I-70...while a few
sprinkles were over the far northeast corner. Precipitation will
come to an end in most spots this evening with only some isolated
showers possibly lingering in the mountains and far northeast
corner overnight.
&&
Aviation...lingering showers around kden were coming to an end
and expect gradual clearing overnight. Light and variable winds
this evening will turn more northerly again by 14z-16z Tuesday
with a few gusts around 20 kts expected Tuesday afternoon.
&&
Hydrology...no concerns.
&&
Previous discussion... /issued 333 PM MDT Monday may 20 2013/
Short term...the broad upper low is way up around the Dakota's
with a broad area of moisture wrapping around the low back into
Colorado. 88d showing quite a bit of scattered showers ongoing
over the mountains and plains this afternoon. Overall...showers
are on the light side and rather fast moving with amounts around
a tenth of an inch or less. The stronger instability is south of
our County Warning Area with some lightning reported across southern portions of
Colorado. Given the strong northwest flow pattern...there is less
activity over the far northeast plains. Showers will dissipate
later this evening as airmass stabilizes. Still expect some
ongoing showers through the night over the eastern plains.
The trend is for slightly warmer and drier conditions on Tuesday
as weak ridging builds in from the west. Will still keep isolated
thunderstorms in the mountains but dry on the northeast plains.
Long term...a few showers and thunderstorms will be possible across
the mountains and along the foothills early Tuesday evening where
weak convergence and low level moisture will linger. Otherwise dry
conditions will prevail with skies clearing. On Wednesday... upper
level ridge builds across the area. Models do indicate an area of
moisture spreading north across the mountains as well as in and
near foothills during the afternoon. Daytime heating will allow
for some convection to develop across the mountains and foothills.
Models show convective available potential energy around 500-1000 j/kg in this area and will
maintain the chance probability of precipitation. A few storms will also be possible along
the urban corridor and adjacent plains where weak southeast winds
will keep low level moisture in place. Further east airmass
appears too stable for convection during the afternoon. Storms
that develop may produce brief moderate rain and gusty winds with
perhaps some small hail. Severe weather is not anticipated.
Temperature and thickness forecasts show temperatures a few degrees
warmer across the plains...with highs in the middle 70s. Storms to
linger into the evening most areas before ending around midnight.
Some increase in low level moisture across plains after
midnight...enough for mostly cloudy conditions. Could be some
stratus over the far northeast corner. On Thursday... flow aloft
becomes southwest as upper ridge moves into the Great Plains and
upper trough moves into the northern Great Basin. Airmass to be
slightly drier though enough moisture across area for a slight
chance of afternoon and evening thunderstorms. Models show
slightly cooler air spreading across the far eastern plains...
temperatures look to be a few degrees cooler at Akron and
Limon...slightly warmer elsewhere.
For the later periods Friday through Memorial Day...southwest flow
aloft to prevail as models show closed low over the northwest
United States. This will result in warmer and drier conditions
with temperatures warming to above normal conditions. Some middle
level moisture spreads across the area Sunday and Monday with a
slight chance of afternoon and evening storms east of the
mountains.
Aviation...scattered showers will continue across the terminals
through early evening hours. Showers will result in ils
conditions as ceilings may lower to around 5000 feet with the
passing showers. Surface winds will be northerly over kden but
more variable and lighter at apa/bjc.
Hydrology...no issues as mainly light amounts with passing
showers given fast storm motions. Generally around a tenth of an
inch with the showers.
&&
Bou watches/warnings/advisories...
none.
&&
$$
Short term...barjenbruch
long term....d-l
aviation...barjenbruch
