Area forecast discussion
National Weather Service Denver/Boulder Colorado
834 PM MDT Tuesday may 21 2013
Update...a few sprinkles near the Palmer Divide will be ending in
the next hour. Forecast is on track.
&&
Aviation...surface high pressure continues to build southward
across the plains. Easterly winds will be slower to transition to
light drainage tonight...and may even be light/variable through
Wednesday morning. Wednesday wind forecast was trended a bit more
easterly in the afternoon. Still looking at just a 20 percent
chance of afternoon high based showers/storm...and about a 30-40
percent chance of gusty winds at some point during the 22z-02z
time frame.
&&
Previous discussion... /issued 304 PM MDT Tuesday may 21 2013/
Short term...the broad upper low continues over the northern
High Plains with still some lingering clouds and gusty winds
wrapping around the low into northeast Colorado. Mainly flat cumulus
over lower elevations and only modest cloud development in the
mountains. Expect only isolated showers in the mountains through
early evening. Clouds and showers will dissipate by later this
evening with mainly clear skies overnight. The exception would be
over far northeast Colorado with lingering clouds there around the
low.
For Wednesday...the weak ridge aloft over the Great Basin will
move over Colorado with weakening winds over the northeast
plains. Low level flow will be turn southeast on the plains
during the afternoon with a bit more return low level moisture.
Should see a better chance of showers and thunderstorms over the
mountains and adjacent plains. Low levels will remain relatively
dry some mainly high based storms with gusty winds. Temperatures
will be warmer on Wednesday with readings back into the 70s across
all of northeast Colorado.
Long term...a few thunderstorms will be possible Wednesday
evening...mainly in and near the foothills where weak easterly
surface flow will provide local upslope. With surface convective available potential energy less
than 500 j/kg...storms will be weak...producing light rainfall.
Gusty outflow winds will be possible near the storms. Airmass
stabilizes after midnight as surge of cooler and moist air moves
across the plains. Storms to end by midnight...though clouds will
increase with perhaps some stratus. Appears there will be enough
of a drainage wind to limit any development of fog. On Thursday...
a drier southwest flow aloft will be over the area as upper trough
moves into the northwest United States. Airmass across plains to
be slightly cooler and a bit more stable. Weak shear and a bit
more low level moisture may be enough to generate a few storms
during the afternoon and early evening...with the best chance in
and near foothills. If storms do develop...they should be weak
producing only light rainfall. Temperature and thickness forecasts
suggest highs across the plains cooling to the upper 60s. Skies
should clear by midnight with drainage winds scouring out most of
the low level moisture. For Friday...southwest flow aloft will
continue to advect drier and warmer air across the area. Still
some moisture over the far eastern sections for a slight chance of
afternoon and evening thunderstorms. Otherwise...dry conditions
will prevail with temperatures across the plains warming into the
lower 80s. On Saturday...models show some middle level moisture
moving into the mountains. Daytime heating may be enough to
generate a few afternoon storms. Also some low level moisture
appears to spread across the eastern plains in weak southeast
flow...mainly east of Denver. Will include a slight chance of
storms. Temperatures across the plains look to warm into the
middle 80s. For the later periods Sunday through Tuesday...
southwest flow aloft to persist with upper trough remaining over
the Great Basin. Appears there will be enough moisture in the middle
levels for a slight chance of afternoon and evening thunderstorms
each day...mainly over the northeast corner of the state where
there looks to be a bit more low level moisture.Temperatures to
remain above normal.
Aviation...gusty northerly winds will diminish early this evening
with a gradual shift to southerly winds later tonight. On
Wednesday...winds will be southeast in the afternoon with a slight
chance of high based showers and storms later in the day.
Coverage looks fairly isolated...so for now no mention of ts in
the terminal forecasts.
Hydrology...no issues through Wednesday as any isolated showers
will produce mainly light rain showers at the most.
&&
Bou watches/warnings/advisories...
none.
&&
$$
Short term...barjenbruch
long term....d-l
aviation...barjenbruch
