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Area forecast discussion
National Weather Service Denver/Boulder Colorado
442 am MDT Fri Apr 26 2019

Short term...(today and tonight)
issued at 302 am MDT Fri Apr 26 2019

West-northwest flow will remain over the area today thru tonight as a weak
upper level trough affects nrn Colorado mainly tonight. For this aftn,
steep lapse rates over the higher terrain will allow for the
development of showers and tstms which will them move rapidly
eastward. Soundings show quite a bit of dcape which would lead to
the potential of strong gusty winds up to 60 mph from the storms.
Across the plains, it will be mainly dry thru most of the aftn
although, a few high based showers and storms may affect the
Palmer Divide. Highs across nern Colorado will warm into the mid 70s to
lower 80s as the low level flow will be from the southwest.

For this evening, as the showers and tstms move off the higher
terrain, will see gusty outflow winds of 50 to 60 mph quickly move
across the plains. Along the leading edge of this boundary, there
will be a chc of high based showers and a few storms as well.
Across the higher terrain, the weak upper level trough and an
accompanying jet Max will move across, and enhance precip
development thru midnight. Thus will see a period of heavier snow
above 10000 ft with some areas seeing from 4 to 8 inches. This
activity should gradually decrease after midnight, although there
will be lingering lighter snow due to favorable orographics. Over
nern Colorado a second wave of shower and tstm activity may occur by
mid to late evening as the weak upper level trough and associated
jet move across. Most of this activity should end shorty after

Long term...(saturday through thursday)
issued at 442 am MDT Fri Apr 26 2019

Models have moderately strong zonal flow over the County Warning Area Saturday
and Saturday night. It becomes more southwesterly on Sunday and
Sunday night and also it increases in speed a bit. There is weak
downward vertical velocity on the qg Omega fields Saturday. There
is weak upward motion progged Saturday night into Sunday evening,
then neutral forcing. The low level wind proggs show normal
diurnal patterns Saturday into Sunday, with a decent cold front
and upslope to move in sometime between 21z to 03z Sunday
afternoon/evening depending on the model. Upslope is progged all
night Sunday night. Moisture is limited for the forecast area on
Saturday and Saturday night. Later on Sunday and Sunday night
moisture is on the slow increase. There is some cape progged over
the western half of the plains Saturday afternoon/evening. It's
not significant. There is more widespread cape over much for the
County Warning Area Sunday, well into the afternoon until the cold front moves
across. Some areas have values over 1000 j/kg in the mountains and
far eastern plains around 21z Sunday afternoon. The qpf fields
have some measurable precipitation around Saturday and Saturday
night, mainly over the mountains. There is slightly more
measurable precipitation over the County Warning Area on Sunday afternoon and
evening. Some of it is associated with the cold front on Sunday.
For pops, will go with "chance"s in the mountains Sunday morning,
then increases them to "likely"s by afternoon into early evening,
then "chance"s again Sunday night into Monday morning. For the
plains will have a few areas of "slight chance"s late day
Saturday. By Sunday afternoon and night will go with 10-40%s over
the plains with highest chances Sunday night. For temperatures,
saturday's highs will be 1-4 c cooler than today. Sunday's cool
off 1-2 c more form saturday's. For the later days, Monday through
Thursday, models show strong southwesterly flow aloft over the
County Warning Area on Monday. A weakened upper closed low over Arizona at 12z
Tuesday moves across Colorado on Tuesday and open wave. On
Wednesday a move substantial upper trough over the northern U.S.
Rockies down into the Great Basin moves eastward across Colorado
Wednesday night into Thursday. The low level wind field keep some
form of upslope over the County Warning Area Monday through Tuesday. More normal
diurnal patterns are progged Wednesday and Thursday. Monday into
Wednesday morning look to be cool and moist. The rest of Wednesday
and Thursday are pretty dry.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 302 am MDT Fri Apr 26 2019

South winds this morning will become more westerly by mid to late
morning. In the aftn, outflow boundaries from convection over the
higher terrain will move across after 22z. Winds will quickly shift
to the west northwest at 20 to 30 mph with potential gusts up to 50
mph for an hour or so. In addition these boundaries may trigger a
few high based storms as well.

After the initial boundaries move across, winds may shift back to
a more west or southwest direction. A second round of showers and
storms may affect the area between 03z and 06z. Winds should not
be as strong, with this second batch of activity, but still could
see gusts up to 30 mph. After midnight things should calm down
with winds going back to drainage.


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