Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/04/20

Area Forecast Discussion

National Weather Service Denver/Boulder CO

 737 PM MDT Sun May 3 2020

.UPDATE...
Issued at 736 PM MDT Sun May 3 2020

A corridor of 500-1000 J/kg CAPE from the far northeastern corner
back southwest toward the Palmer Divide is finally starting to be
able to be utilized evident on radar. Lift ahead of the upper
trough may be finally weakening the cap that has been shown on
ACARS soundings around 620mb. With the jet nearby and bulk shear
of 50-70 kts, will continue to see threats of large hail and
damaging winds tonight, and won`t be able to rule out a tornado.
The biggest threat of severe strength storms will be mainly along
and east of a line from Sterling down to western Elbert County.
Main pressure rises still up in southwestern to northern Wyoming,
so a cold frontal timing of near midnight into the metro areas
still looks good. Will continue to see a chance of showers and
thunderstorms ahead of this front, as well as behind it into the
early morning hours with lift increasing ahead of the upper
trough.

&&

.SHORT TERM...(This evening through Monday)
Issued at 146 PM MDT Sun May 3 2020

Latest RAP/HRRR runs still want to initiate showers/thunderstorms
over the Cheyenne Ridge and Palmer Divide after 3 pm. A few storms
are developing along the northern border in closer to a broad 100+
kt jet stream that northern CA into eastern NE. Most of activity
through 8 pm this evening looks like it will be confined to these
areas. Temperatures have warmed up into the lower 70s, not enough
to break the cap and generate more storms. Sufficient CAPES
around to still produce an isolated severe thunderstorm with the
best chance along the northern border. Main concerns will be hail
to one inch and wind gusts to 60 mph. Outflow boundaries generated
by these storms may help get the storms going elsewhere. CAPES
over the northeast plains this afternoon, ranging from 500-1000
j/kg, highest over the northeast corner of the state. Models start
to enhance the thunderstorms over the northeast plains late this
evening and overnight. Better lift develops in the mid and upper
levels as an embedded short wave moved across northern. Good shear
profile as well, with the models showing stronger thunderstorms
developing mainly north and east of Denver from 9pm to 2am, with
some lingering activity continuing on the northern border through
6am Monday morning. Weak to moderate mid level QG ascent over the
forecast area this evening, weaker ascent after midnight, with
moderate subsidence spreading from northwest to southeast across
the forecast area on Monday. Late tonight into Monday morning, a
cold front will push north to south across the Denver area.
Coverage for showers and thunderstorms with be lower. Some low
level instability around on Monday, but overall the storms will be
weaker as well.

.LONG TERM...(Monday night through Sunday)
Issued at 146 PM MDT Sun May 3 2020

Flat upper level ridge will be over the western states with a
west- northwest flow aloft over Colorado. A cold front that pushes
through Colorado Monday should leave dry and stable conditions in
its wake. A few models show weak convection forming over the
higher terrain Monday evening and Tuesday afternoon. Will have low
PoPs for this. If anything forms it should be weak and short
lived. Temperatures on Tuesday will be near normal with highs in
the upper 60s to lower 70s.

The ridge over the western U.S. will slide east across the
Central Rockies Wednesday. This will bring warmer temperatures
with highs in the mid 70s across northeast Colorado. Surface high
pressure over the Northern and Central Plains will cause surface
winds to turn southeasterly Wednesday. This could transport enough
moisture for convection. With the ridge overhead, any convective
development will be battling warm air aloft and subsidence. Thus
will keep PoPs on the low side.

A ridge over the western U.S. will amplify into Canada Thursday.
This ridge will remain nearly stationary through Sunday. A long
wave trough will reside over the Great Lakes and eastern Canada
during this time frame. For Colorado, this will result in a
northwest flow aloft. Models show 2-3 short wave troughs embedded
in the northwest flow from Thursday to Sunday. Colorado will be on
the edge of the cooler air that each of these trough will bring.
Still a good amount of uncertainty on how far western each of
these troughs will dig. There should be a cold front sometime
Thursday, after this timing any front is difficult. Will have a
cooler day for Friday behind the front. For the weekend will keep
temperatures at or slightly below normal. This is not a good setup
for convection or precipitation. Can`t rule out something late
next week due to the uncertainty, so will have low PoPs for this.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 736 PM MDT Sun May 3 2020

Instability is increasing across the area, bringing a better
chance to see showers and thunderstorms over the terminals. The
chance will be increasing toward the cold frontal passage expected
around midnight. Until then, VFR conditions will be expected with
north-northeasterly winds. Occasional ILS restrictions due to
showers and thunderstorms this evening with ceilings 050-060 kft,
before the cold front will likely bring prevailing ceilings of
050-060 kft through about 12z. The cold front will likely have
winds of 15g25kts associated with it, then the winds should trend
down but stay northerly. Northerly winds will persist through the
day on Monday, with some slight backing to the northwest during
the afternoon.


&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Kriederman
SHORT TERM...Cooper
LONG TERM...Meier
AVIATION...Kriederman