Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/30/16
Area Forecast Discussion
National Weather Service Grand Junction CO
445 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday night)
Issued at 303 PM MDT Sun May 29 2016
Split troughy pattern over the Rockies will progress eastward
over the next couple of days. The southern closed low trekking
across SoCal today will allow for some added instability late
Monday afternoon and through the night with pieces of energy
pushing in to the northern Four Corners ahead of the unstable air
mass. As mentioned in the previous forecast discussion overall
the models have downscaled activity for Monday afternoon, but
with the vort kickers and ever so slightly increased bulk shear I
would expect more activity than today. High and low temperatures
will remain around normal over the next few days.
.LONG TERM...(Tuesday through Sunday)
Issued at 303 PM MDT Sun May 29 2016
The closed low will stall over Arizona, propagate southward,
and stay south of our forecast area through Wednesday before it
weakens. During this time frame, afternoon convection should stay
anchored over the higher terrain for the most part. In the
meantime, 500 mb heights strengthen high pressure over the
western US and qill slowly shift its axis over eastern Utah and
western Colorado by next weekend. Summer-like weather will truly
show up late this week and next weekend as temperatures soar into
the 90s across the lower valleys and into the upper 60s in the
high mountains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 439 PM MDT Sun May 29 2016
Scattered showers and thunderstorms will continue across the area
through about 03z this evening. Storms will be focused most
strongly over the mountains of western CO and northeast Utah. The
strongest cells will be capable producing outflow winds to 40 MPH
and will briefly obscure mountains. Brief MVFR vsbys and ils cigs
are possible at kase...kege...kril...ktex and kvel. After 03z
storms will dissipate and winds will transition to light and
terrain driven. Similar shower and thunderstorms development is
expected after 17Z Monday.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...JAM
LONG TERM...JAM
AVIATION...CC
Area Forecast Discussion
National Weather Service Grand Junction CO
1036 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1036 MDT Sun May 29 2016
VFR conditions will prevail at airports across eastern Utah and
western Colorado through the next 24 hours. However, daytime
warming and residual moisture will combine to generate scattered
showers and thunderstorms over the higher terrain from 18Z through
03Z this evening. The strongest cells will be capable producing
outflow winds to 35 MPH and will briefly obscure mountains.
Otherwise, winds will be relatively light and terrain driven.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...NL
[top]
Area Forecast Discussion
National Weather Service Denver/Boulder CO
351 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today and tonight)
Issued at 351 AM MDT Sun May 29 2016
Westerly flow aloft will become southerly later today and tonight
as an upper level low moves across southern California. Water
vapor satellite imagery is showing a weak short wave trough over
southwest New Mexico. Models show this wave lifting northeast
through the day. This wave may help trigger storms over southern
parts of the area. Airmass becomes unstable again this afternoon
with CAPE values up to 1000 J/kg. Could see slightly higher values
over the eastern plains if more moisture advects into the area.
Overall, expect similar thunderstorm coverage as yesterday, mainly
scattered storms. There will be a little better chance for hail
with the storms today because of the increased CAPE. However CAPE
and shear will be on lower side, so not expecting severe storms.
However, can`t rule out one or two storms just reaching severe
threshold over the eastern plains. As far as temperatures go,
highs will be 2 to 6 degrees warmer today.
.LONG TERM...(Monday through Saturday)
Issued at 351 AM MDT Sun May 29 2016
Low amplitude upper level ridge shifts east of Colorado on Monday
allowing a long wave upper trough to pass over the region Monday
night and Tuesday. The closed low associated with this trough over
western Arizona is forecast to weaken as it tracks slowly
southeast towards the U.S./Mexico border...while the upper low
over western Montana is projected to gain strength as its drops
southeast clipping nern Wyoming along the way. Monday should start
out dry and mild across the CWA with near zonal flow aloft. Then
as temperatures quickly warm should see scattered showers/t-storms
blossoming over the high terrain around midday. Should see some
of this convection carried off the Front Range during the
afternoon tied to a weak disturbance embedded in the wly flow
aloft. By evening could see some intensification in these t-storms
as they advance into higher dewpts and steeper lapse rates across
far eastern sections of the CWA. Cannot rule out a few hail and
heavy rain producers in this area during the evening hours.
As the northern low passes to our north Monday night...northerly
flow on its back side drives a cold front through nern Colorado
during the pre-dawn hours. Synoptic scale forcing for ascent
appears weak with the upper trough...however during the day
Tuesday models show a deepening northeasterly/upslope flow on the
plains producing a heavy cloud cover and cooler temperatures as
well as areas of light precip. Most of this showery precip is
expected to fall east of the Continental Divide late Monday night
and much of Tuesday with 12-hour precip totals generally a
quarter inch or less. Could see locally heavier amounts in the
foothills to the west and southwest of Denver. Farther out on the
plains...amounts anywhere from a trace to a tenth of an inch.
High temperatures go from around average on Monday to as much as
10-12 degs f below average on Tuesday...with the greatest cooling
likely to occur east of the Cont Dvd.
Tuesday night and beyond...the upper trough shifts over the
northern Great Plains allowing an upper level ridge to gain
strength over the Great Basin. Models show this building ridge
with its warmer temperatures and drier air migrating eastward over
Colorado by Friday. Should see a significant reduction in cloud
cover and limited chances for showers/t-storms with its arrival.
Guidance indicates highs both days in the low to mid-80s on the
plains of northeast Colorado.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 351 AM MDT Sun May 29 2016
Scattered thunderstorms are expected to form over the higher
terrain and spread eastward through the afternoon and evening.
Best time for thunderstorms in the Denver area is 21z-01z. Will go
with a PROB30 in the TAFs at this time. The storms will be capable
of heavy rain, small hail and wind gusts to 35 knots. Winds will
generally be southerly today at KDEN, except when outflow winds
from showers and storms occur.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Meier
Area Forecast Discussion
National Weather Service Grand Junction CO
322 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
&&
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 321 AM MDT Sun May 29 2016
Visual Flight Rules will dominate the forecast over the next 24
hours at the forecast terminals. Instability from heating of the
day and residual moisture will again lead to isolated and
scattered thunderstorm development over the region...favoring the
higher terrain. Gusty outflow winds to 40 mph will be more of a
threat than heavy rainfall...therefor probabilities are quite low
for VFR conditions to be compromised. ILS break points may be
temporary met by passing showers at the KASE KRIL and KEGE
terminals.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
827 PM MDT SAT MAY 28 2016
.UPDATE...
Issued at 825 PM MDT Sat May 28 2016
Still some decent storms on the plains, mainly in pockets of
untapped air. Activity is decreasing overall. I will need to add
some low pops to the northeast corner for a few hours after
midnight in case the current activity around Greeley persists or
there is the redevelopment that the HRRR has been showing on weak
outflows coming back in from the northeast. Already added in the
evening showers over the mountains but these should be much less
by midnight. Rest of the forecast is looking good.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 321 PM MDT Sat May 28 2016
Have seen isolated-scattered showers and a few thunderstorms form
over the mountains and drift eastward out onto the plains over the
past couple hours. Should continue seeing this activity for a few
more hours. Brief heavy rains and small hail will be the main
threats through the early evening. Loss of daytime heating through
the evening will allow showers to come to an end by mid-evening.
Weak westerly flow aloft will continue over the state again on
Sunday, with enough moisture and instability for showers to
develop over the mountains and move over the plains. Model
soundings show CAPE values over 2000 j/kg, so there should be a
bit more strength to the showers that develop. Winds aloft will be
weak, so the threat of locally heavier rain will increase.
Precipitable water values are also forecast to be above .75 inches
late in the afternoon and early evening.
The GFS and ECMWF models are not as wet as the NAM solutions, so
will temper the PoPs back a little bit across the northeast
Colorado plains, in case the shower activity remains in and near
the foothill areas. Otherwise, temperatures will be around
seasonal normals.
.LONG TERM...(Sunday night through Saturday)
Issued at 321 PM MDT Sat May 28 2016
There is weak west-southwesterly flow aloft progged for the
forecast area Sunday night and Monday. By Monday night well into
Tuesday...an upper trough will move into Colorado and the CWA. The
flow aloft stays weak. By 12z Tuesday morning, the upper trough is
through and there is northwesterly flow aloft. There is weak
upward QG motion in the synoptic scale Sunday night into Tuesday
evening, before downward motion moves in by 12z Wednesday morning.
The boundary layer flow will likely adhere to normal diurnal
patterns Sunday night through Monday evening. Models show a decent
cold front with north-northeasterly upslope winds behind it moving
down across the plains and foothills from 06Z to 09Z. The upslope
is progged to continue all day Tuesday and Tuesday night. For
moisture, there is quite a bit over all the CWA through Tuesday
evening, then it decreases overnight. There is fairly decent cape
progged for much of the CWA Sunday evening and late day Monday.
The only decent cape for late day Tuesday is over the mountains
and foothills. The lapse rates are pretty steep much of the time,
except for the plains on Tuesday. It looks somewhat stable behind
the front in the upslope. The best QPF coverage for the CWA is
progged for late day Monday. There are decent amounts of
measurable rainfall in the mountains late day Tuesday as well. for
pops...will go with 30-60%s in the mountains Sunday evening, late
day Monday and late day Tuesday. The plains will have 10-40%s for
those three periods. For temperatures, Monday`s highs are 0-2 C
warmer than Sunday`s highs. Tuesday`s readings are 2-6 C colder
than Monday`s. For the later days, Wednesday through Saturday,
models have northwesterly flow aloft for the forecast area, with
an upper ridge to our west moving towards Colorado. The ridge axis
stays west of our state over Utah through Saturday. The airmass
over the CWA dries out quite a bit and warms up to slightly above
normal temperatures by Friday and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 825 PM MDT Sat May 28 2016
VFR through Sunday. Still some showers and thunderstorms around
mainly east of Denver for the next couple of hours, but very low
chance of anything affecting the Denver area terminals. Widely
scattered storms expected again late Sunday afternoon with short
lived impacts of heavy rain, small hail, and wind gusts to 40
knots possible with some of the storms.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Gimmestad
SHORT TERM...Dankers
LONG TERM...RJK
AVIATION...Gimmestad
Area Forecast Discussion
National Weather Service Pueblo CO
1123 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday)
Issued at 237 PM MDT Sun May 29 2016
...Chance for strong to severe thunderstorms increases for Monday
across the plains...
Embedded shortwave ejecting northeast into CO has fired off showers
and thunderstorms over the mountains. Strongest convection this
afternoon is expected to fire along and east of a dryline across the
far eastern counties. SPC meso analysis shows around 1500-2500 J/kg
across the far southeast counties of eastern Las Animas, Baca and
Prowers counties as of 20z. Effective bulk shears will be running
around 30-40 kts, especially if sfc winds can shift a bit
southeasterly, so potential exists for an isolated severe
thunderstorm through the early evening. Otherwise, expect isolated
to scattered showers and thunderstorms with some small hail and
gusty winds possible. Thunderstorms should diminish overnight.
Monday will be a similar set up to today. Upper low over SW CA will
move eastward into AZ, at the same time a northern stream upper trof
drops into the northern U.S. Rockies. With approach of these
systems, suspect sfc winds will stay more southeasterly on Monday
which may serve to keep 40s to mid 50 sfc dew points across the
southeast plains to the north of a sfc boundary which will run along
the highway 50 corridor, southeastward to Kim by afternoon. Mid
level winds look a little weak, which may limit deep layer shear
some. But with CAPES running from 800-2000+ J/KG, this could lead to
a couple severe thunderstorms again Monday afternoon. Best threat
area will be to the east of La Junta, but depending on how much
low level moisture can be maintained farther west, its possible
that portions of El Paso county could see a strong to severe
thunderstorm Monday afternoon as well. Highest pops will be
across the mountains, El Paso county and the far eastern plains
Monday afternoon.
.LONG TERM...(Monday night through Sunday)
Issued at 237 PM MDT Sun May 29 2016
...Wet weather for Tuesday/Tuesday Night for SE Mountains/Adjacent
Plains...
Upper low across MT/WY will move eastward into the Dakotas by Tues
morning while trailing trof/upper low slowly meanders eastward over
AZ. Northern stream system will drop a cold front through the
southeast plains Monday night/Tuesday morning, though initially
appears northerly surge will be influenced more by convective
outflows from thunderstorms along the Palmer Divide and northeast
CO, with cooler air lagging until late Monday night/Tuesday
morning. Will keep thunderstorms going across the southeast plains
as there will probably be enough convergence along the boundary
for thunderstorm initiation. Best chance for any severe
thunderstorms Monday evening will be east of La Junta again where
deeper moisture will reside. Could also see a strong storm or two
along the Palmer Divide, but this will depend on how much low
level moisture is maintained.
Models in better agreement on Tuesday, driving the front well
southward into NE NM by 18z Tues. Should see upslope
showers/thunderstorms develop over the southeast mountains fairly
early in the day. However, suspect that Northerly surface winds will
also send some modestly drier air into the southeast plains during
the afternoon. Theta E ridge/axis of higher dew points will
likely reside across NE NM/TX Panhandle region, along and north
of the frontal boundary. Still plenty of moisture/instability over
the mountain, particularly the SE Mts, for fairly widespread
showers and thunderstorms on Tuesday. Could be a strong storm or
two over the mountains as well though think CAPE is overdone in
the NAM. Both NAM and GFS carry precipitation into the overnight
hours across the southeast mountains/adjacent plains, though 12z
GFS looks convectively contaminated after 06z given its over an
inch bulls eye over the Pikes Peak region and Wet mountains. More
likely scenario will be for focus to be shifting southward along
the SE Mts/I-25 corridor during the overnight hours with Wets and
southern Sangre De Cristo mountains seeing max precipitation
during the overnight hours. Main concern besides a strong to
marginally severe storm or two Tuesday afternoon will be the
potential for heavy rainfall on area burn scars. NE flow would
tend to favor the Wets and Sangres for this risk...but Waldo burn
scar will also be under the threat. Otherwise far eastern plains
may end up being too cool and stable for much more than isolated
rain showers Tuesday/Tuesday night. Snow levels Tuesday night look
to stay around 10kft, possibly dropping to 9Kft Wednesday morning.
Higher elevations above 10kft could pick up several inches of wet
snow.
Wednesday looks cool and stable across the plains, but continued
unsettled over the mountains with another round of scattered showers
and thundestorms. Upper ridge will build over the western U.S from
Thursday through next weekend bringing a good warm up for the
region. Still enough moisture for isolated to low end scattered
thunderstorms mainly over the mountains each day. -KT
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1118 PM MDT Sun May 29 2016
VFR conditions expected at taf sites overnight, with light
drainage flows developing by sunrise Mon. Tsra will develop over
the higher terrain after 18z Mon, with a few storms spreading to
lower elevations late in the day. KCOS has the best chance for a
storm during the day, though have included a vcts mention at all
taf sites for a few hrs mid/late afternoon. Main threat with any
storms will be gusty outflow winds, as low levels along I-25 and
and westward will stay fairly dry. Convection will shift east
onto the plains Mon evening, with clearing skies at all taf sites
after 00z.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...KT
AVIATION...PETERSEN
[top]
Area Forecast Discussion
National Weather Service Grand Junction CO
445 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday night)
Issued at 303 PM MDT Sun May 29 2016
Split troughy pattern over the Rockies will progress eastward
over the next couple of days. The southern closed low trekking
across SoCal today will allow for some added instability late
Monday afternoon and through the night with pieces of energy
pushing in to the northern Four Corners ahead of the unstable air
mass. As mentioned in the previous forecast discussion overall
the models have downscaled activity for Monday afternoon, but
with the vort kickers and ever so slightly increased bulk shear I
would expect more activity than today. High and low temperatures
will remain around normal over the next few days.
.LONG TERM...(Tuesday through Sunday)
Issued at 303 PM MDT Sun May 29 2016
The closed low will stall over Arizona, propagate southward,
and stay south of our forecast area through Wednesday before it
weakens. During this time frame, afternoon convection should stay
anchored over the higher terrain for the most part. In the
meantime, 500 mb heights strengthen high pressure over the
western US and qill slowly shift its axis over eastern Utah and
western Colorado by next weekend. Summer-like weather will truly
show up late this week and next weekend as temperatures soar into
the 90s across the lower valleys and into the upper 60s in the
high mountains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 439 PM MDT Sun May 29 2016
Scattered showers and thunderstorms will continue across the area
through about 03z this evening. Storms will be focused most
strongly over the mountains of western CO and northeast Utah. The
strongest cells will be capable producing outflow winds to 40 MPH
and will briefly obscure mountains. Brief MVFR vsbys and ils cigs
are possible at kase...kege...kril...ktex and kvel. After 03z
storms will dissipate and winds will transition to light and
terrain driven. Similar shower and thunderstorms development is
expected after 17Z Monday.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...JAM
LONG TERM...JAM
AVIATION...CC
Area Forecast Discussion
National Weather Service Grand Junction CO
1036 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1036 MDT Sun May 29 2016
VFR conditions will prevail at airports across eastern Utah and
western Colorado through the next 24 hours. However, daytime
warming and residual moisture will combine to generate scattered
showers and thunderstorms over the higher terrain from 18Z through
03Z this evening. The strongest cells will be capable producing
outflow winds to 35 MPH and will briefly obscure mountains.
Otherwise, winds will be relatively light and terrain driven.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...NL
[top]
Area Forecast Discussion
National Weather Service Denver/Boulder CO
351 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today and tonight)
Issued at 351 AM MDT Sun May 29 2016
Westerly flow aloft will become southerly later today and tonight
as an upper level low moves across southern California. Water
vapor satellite imagery is showing a weak short wave trough over
southwest New Mexico. Models show this wave lifting northeast
through the day. This wave may help trigger storms over southern
parts of the area. Airmass becomes unstable again this afternoon
with CAPE values up to 1000 J/kg. Could see slightly higher values
over the eastern plains if more moisture advects into the area.
Overall, expect similar thunderstorm coverage as yesterday, mainly
scattered storms. There will be a little better chance for hail
with the storms today because of the increased CAPE. However CAPE
and shear will be on lower side, so not expecting severe storms.
However, can`t rule out one or two storms just reaching severe
threshold over the eastern plains. As far as temperatures go,
highs will be 2 to 6 degrees warmer today.
.LONG TERM...(Monday through Saturday)
Issued at 351 AM MDT Sun May 29 2016
Low amplitude upper level ridge shifts east of Colorado on Monday
allowing a long wave upper trough to pass over the region Monday
night and Tuesday. The closed low associated with this trough over
western Arizona is forecast to weaken as it tracks slowly
southeast towards the U.S./Mexico border...while the upper low
over western Montana is projected to gain strength as its drops
southeast clipping nern Wyoming along the way. Monday should start
out dry and mild across the CWA with near zonal flow aloft. Then
as temperatures quickly warm should see scattered showers/t-storms
blossoming over the high terrain around midday. Should see some
of this convection carried off the Front Range during the
afternoon tied to a weak disturbance embedded in the wly flow
aloft. By evening could see some intensification in these t-storms
as they advance into higher dewpts and steeper lapse rates across
far eastern sections of the CWA. Cannot rule out a few hail and
heavy rain producers in this area during the evening hours.
As the northern low passes to our north Monday night...northerly
flow on its back side drives a cold front through nern Colorado
during the pre-dawn hours. Synoptic scale forcing for ascent
appears weak with the upper trough...however during the day
Tuesday models show a deepening northeasterly/upslope flow on the
plains producing a heavy cloud cover and cooler temperatures as
well as areas of light precip. Most of this showery precip is
expected to fall east of the Continental Divide late Monday night
and much of Tuesday with 12-hour precip totals generally a
quarter inch or less. Could see locally heavier amounts in the
foothills to the west and southwest of Denver. Farther out on the
plains...amounts anywhere from a trace to a tenth of an inch.
High temperatures go from around average on Monday to as much as
10-12 degs f below average on Tuesday...with the greatest cooling
likely to occur east of the Cont Dvd.
Tuesday night and beyond...the upper trough shifts over the
northern Great Plains allowing an upper level ridge to gain
strength over the Great Basin. Models show this building ridge
with its warmer temperatures and drier air migrating eastward over
Colorado by Friday. Should see a significant reduction in cloud
cover and limited chances for showers/t-storms with its arrival.
Guidance indicates highs both days in the low to mid-80s on the
plains of northeast Colorado.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 351 AM MDT Sun May 29 2016
Scattered thunderstorms are expected to form over the higher
terrain and spread eastward through the afternoon and evening.
Best time for thunderstorms in the Denver area is 21z-01z. Will go
with a PROB30 in the TAFs at this time. The storms will be capable
of heavy rain, small hail and wind gusts to 35 knots. Winds will
generally be southerly today at KDEN, except when outflow winds
from showers and storms occur.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Meier
Area Forecast Discussion
National Weather Service Grand Junction CO
322 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
&&
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 321 AM MDT Sun May 29 2016
Visual Flight Rules will dominate the forecast over the next 24
hours at the forecast terminals. Instability from heating of the
day and residual moisture will again lead to isolated and
scattered thunderstorm development over the region...favoring the
higher terrain. Gusty outflow winds to 40 mph will be more of a
threat than heavy rainfall...therefor probabilities are quite low
for VFR conditions to be compromised. ILS break points may be
temporary met by passing showers at the KASE KRIL and KEGE
terminals.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
827 PM MDT SAT MAY 28 2016
.UPDATE...
Issued at 825 PM MDT Sat May 28 2016
Still some decent storms on the plains, mainly in pockets of
untapped air. Activity is decreasing overall. I will need to add
some low pops to the northeast corner for a few hours after
midnight in case the current activity around Greeley persists or
there is the redevelopment that the HRRR has been showing on weak
outflows coming back in from the northeast. Already added in the
evening showers over the mountains but these should be much less
by midnight. Rest of the forecast is looking good.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 321 PM MDT Sat May 28 2016
Have seen isolated-scattered showers and a few thunderstorms form
over the mountains and drift eastward out onto the plains over the
past couple hours. Should continue seeing this activity for a few
more hours. Brief heavy rains and small hail will be the main
threats through the early evening. Loss of daytime heating through
the evening will allow showers to come to an end by mid-evening.
Weak westerly flow aloft will continue over the state again on
Sunday, with enough moisture and instability for showers to
develop over the mountains and move over the plains. Model
soundings show CAPE values over 2000 j/kg, so there should be a
bit more strength to the showers that develop. Winds aloft will be
weak, so the threat of locally heavier rain will increase.
Precipitable water values are also forecast to be above .75 inches
late in the afternoon and early evening.
The GFS and ECMWF models are not as wet as the NAM solutions, so
will temper the PoPs back a little bit across the northeast
Colorado plains, in case the shower activity remains in and near
the foothill areas. Otherwise, temperatures will be around
seasonal normals.
.LONG TERM...(Sunday night through Saturday)
Issued at 321 PM MDT Sat May 28 2016
There is weak west-southwesterly flow aloft progged for the
forecast area Sunday night and Monday. By Monday night well into
Tuesday...an upper trough will move into Colorado and the CWA. The
flow aloft stays weak. By 12z Tuesday morning, the upper trough is
through and there is northwesterly flow aloft. There is weak
upward QG motion in the synoptic scale Sunday night into Tuesday
evening, before downward motion moves in by 12z Wednesday morning.
The boundary layer flow will likely adhere to normal diurnal
patterns Sunday night through Monday evening. Models show a decent
cold front with north-northeasterly upslope winds behind it moving
down across the plains and foothills from 06Z to 09Z. The upslope
is progged to continue all day Tuesday and Tuesday night. For
moisture, there is quite a bit over all the CWA through Tuesday
evening, then it decreases overnight. There is fairly decent cape
progged for much of the CWA Sunday evening and late day Monday.
The only decent cape for late day Tuesday is over the mountains
and foothills. The lapse rates are pretty steep much of the time,
except for the plains on Tuesday. It looks somewhat stable behind
the front in the upslope. The best QPF coverage for the CWA is
progged for late day Monday. There are decent amounts of
measurable rainfall in the mountains late day Tuesday as well. for
pops...will go with 30-60%s in the mountains Sunday evening, late
day Monday and late day Tuesday. The plains will have 10-40%s for
those three periods. For temperatures, Monday`s highs are 0-2 C
warmer than Sunday`s highs. Tuesday`s readings are 2-6 C colder
than Monday`s. For the later days, Wednesday through Saturday,
models have northwesterly flow aloft for the forecast area, with
an upper ridge to our west moving towards Colorado. The ridge axis
stays west of our state over Utah through Saturday. The airmass
over the CWA dries out quite a bit and warms up to slightly above
normal temperatures by Friday and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 825 PM MDT Sat May 28 2016
VFR through Sunday. Still some showers and thunderstorms around
mainly east of Denver for the next couple of hours, but very low
chance of anything affecting the Denver area terminals. Widely
scattered storms expected again late Sunday afternoon with short
lived impacts of heavy rain, small hail, and wind gusts to 40
knots possible with some of the storms.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Gimmestad
SHORT TERM...Dankers
LONG TERM...RJK
AVIATION...Gimmestad
AREA FORECAST DISCUSSION
NWS Tulsa OK
1133 PM CDT SUN MAY 29 2016
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Mainly VFR conditions will prevail through the forecast period.
Isolated to scattered showers and thunderstorms will be possible
just about any time, but have limited the mention to the most
likely time frames. Brief MVFR or lower conditions will be
possible within any thunderstorm.
&&
.PREV DISCUSSION... /ISSUED 931 PM CDT SUN MAY 29 2016/
DISCUSSION...
Diurnal convection across our area is on the decline this evening.
Will maintain low pops overnight for the possibility of additional
pop up activity, but severe weather is no longer expected. The
large MCS across southwest Oklahoma and northwest Texas is likely
to remain mainly to our west and south overnight.
Update on the way.
TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
$$
SHORT TERM...20
LONG TERM....05
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...05
[top]
Area Forecast Discussion
National Weather Service Norman OK
352 PM CDT SUN MAY 29 2016
.DISCUSSION...
Complex convective forecast continues with little help from any
model consistency or model agreement. Main area for convective
impacts first period will be far western and southwest parts of
Oklahoma and western north Texas as storms over Texas Panhandle
tries to build east and southeast near edge of West Texas
instability axis. Other areas of potential concentration will be
south-central and southeast Oklahoma where slightly better
moisture resides near weak outflow boundary. An outflow boundary
from northern Oklahoma convection will also move slowly south
toward the I-40 corridor of central Oklahoma and could be a focus
for at least isolated thunderstorms. Majority of heavy rain will
likely be west of the body of Oklahoma and western north Texas but
eventual eastward progression of any MCS may affect southwest
Oklahoma and western north Texas tonight. At this point we are
not issuing a flood watch but slow moving storms tonight will
yield the threat for heavy rain.
Wet weather will continue through at least Wednesday before drier
and cooler air filters in behind seasonably strong cold front.
Convection Tuesday and Wednesday associated with this front will
likely yield the greater threat for widespread heavy rain and need
for flood watches.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 64 81 64 81 / 30 40 30 60
Hobart OK 64 83 65 82 / 50 40 40 60
Wichita Falls TX 64 84 66 83 / 60 40 40 50
Gage OK 60 83 62 80 / 40 30 40 70
Ponca City OK 63 81 64 81 / 40 40 30 60
Durant OK 66 84 67 83 / 30 40 20 30
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
06/11
Area Forecast Discussion
National Weather Service Norman OK
640 AM CDT SUN MAY 29 2016
.DISCUSSION...
&&
.AVIATION...
Showers over northwest Oklahoma will continue to drift southeast
and may develop some thunder later this morning. Later this
afternoon, thunderstorms on the dryline in Texas are expected to
enter west central or southwest Oklahoma and drift southeast over
night. mvfr conditions are generally expected over much of western
and central Oklahoma. Outside of thunderstorms, winds will be
southeast.
&&
.PREV DISCUSSION... /issued 250 AM CDT SUN MAY 29 2016/
DISCUSSION...
The morning`s forecast is dominated by the north Texas complex of
thunderstorms. These are expected to slowly drift east/southeast
and mostly dissipate later this morning. models are very disparate
regarding location of rain and thunderstorms later today. while
the deep moisture and dryline are givens, the impact of upslope
boundary layer flow and a weak upper wave makes it difficult to
place new initiation. the HRRR and nam indicate that a complex of
thunderstorms will begin in the eastern oklahoma and texas
panhandles and move through the western half of Oklahoma later
today. These would move into southwest Oklahoma this evening and
probably join with other storms moving east from the dryline in
the central or southern Texas panhandle. Depending on storm
location/movement some parts of north Texas could get heavy
rainfall again Sunday night. Confidence is too low presently for a
flood watch. Uncertainty is also high for Monday night and Tuesday
morning when another weak upper wave is expected to pass through
a similarly very wet airmass. Some enhancement has been made to
pops in southwest Oklahoma and nearby Texas for another complex
that may move off the dryline to the west of Oklahoma. By later
Tuesday into early Wednesday there is still fair agreement on a
front moving slowly through Oklahoma and bringing widespread rain
and thunderstorms. The front should clear the Red River Wednesday
night and bring somewhat drier and milder air for the rest of the
week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 82 64 82 65 / 50 30 40 30
Hobart OK 83 63 82 65 / 50 50 30 30
Wichita Falls TX 84 64 84 66 / 50 60 40 30
Gage OK 81 60 82 63 / 60 40 20 20
Ponca City OK 83 63 82 65 / 40 30 30 20
Durant OK 85 66 83 67 / 30 30 50 20
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
10/09/09
Area Forecast Discussion
National Weather Service Pueblo CO
1123 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday)
Issued at 237 PM MDT Sun May 29 2016
...Chance for strong to severe thunderstorms increases for Monday
across the plains...
Embedded shortwave ejecting northeast into CO has fired off showers
and thunderstorms over the mountains. Strongest convection this
afternoon is expected to fire along and east of a dryline across the
far eastern counties. SPC meso analysis shows around 1500-2500 J/kg
across the far southeast counties of eastern Las Animas, Baca and
Prowers counties as of 20z. Effective bulk shears will be running
around 30-40 kts, especially if sfc winds can shift a bit
southeasterly, so potential exists for an isolated severe
thunderstorm through the early evening. Otherwise, expect isolated
to scattered showers and thunderstorms with some small hail and
gusty winds possible. Thunderstorms should diminish overnight.
Monday will be a similar set up to today. Upper low over SW CA will
move eastward into AZ, at the same time a northern stream upper trof
drops into the northern U.S. Rockies. With approach of these
systems, suspect sfc winds will stay more southeasterly on Monday
which may serve to keep 40s to mid 50 sfc dew points across the
southeast plains to the north of a sfc boundary which will run along
the highway 50 corridor, southeastward to Kim by afternoon. Mid
level winds look a little weak, which may limit deep layer shear
some. But with CAPES running from 800-2000+ J/KG, this could lead to
a couple severe thunderstorms again Monday afternoon. Best threat
area will be to the east of La Junta, but depending on how much
low level moisture can be maintained farther west, its possible
that portions of El Paso county could see a strong to severe
thunderstorm Monday afternoon as well. Highest pops will be
across the mountains, El Paso county and the far eastern plains
Monday afternoon.
.LONG TERM...(Monday night through Sunday)
Issued at 237 PM MDT Sun May 29 2016
...Wet weather for Tuesday/Tuesday Night for SE Mountains/Adjacent
Plains...
Upper low across MT/WY will move eastward into the Dakotas by Tues
morning while trailing trof/upper low slowly meanders eastward over
AZ. Northern stream system will drop a cold front through the
southeast plains Monday night/Tuesday morning, though initially
appears northerly surge will be influenced more by convective
outflows from thunderstorms along the Palmer Divide and northeast
CO, with cooler air lagging until late Monday night/Tuesday
morning. Will keep thunderstorms going across the southeast plains
as there will probably be enough convergence along the boundary
for thunderstorm initiation. Best chance for any severe
thunderstorms Monday evening will be east of La Junta again where
deeper moisture will reside. Could also see a strong storm or two
along the Palmer Divide, but this will depend on how much low
level moisture is maintained.
Models in better agreement on Tuesday, driving the front well
southward into NE NM by 18z Tues. Should see upslope
showers/thunderstorms develop over the southeast mountains fairly
early in the day. However, suspect that Northerly surface winds will
also send some modestly drier air into the southeast plains during
the afternoon. Theta E ridge/axis of higher dew points will
likely reside across NE NM/TX Panhandle region, along and north
of the frontal boundary. Still plenty of moisture/instability over
the mountain, particularly the SE Mts, for fairly widespread
showers and thunderstorms on Tuesday. Could be a strong storm or
two over the mountains as well though think CAPE is overdone in
the NAM. Both NAM and GFS carry precipitation into the overnight
hours across the southeast mountains/adjacent plains, though 12z
GFS looks convectively contaminated after 06z given its over an
inch bulls eye over the Pikes Peak region and Wet mountains. More
likely scenario will be for focus to be shifting southward along
the SE Mts/I-25 corridor during the overnight hours with Wets and
southern Sangre De Cristo mountains seeing max precipitation
during the overnight hours. Main concern besides a strong to
marginally severe storm or two Tuesday afternoon will be the
potential for heavy rainfall on area burn scars. NE flow would
tend to favor the Wets and Sangres for this risk...but Waldo burn
scar will also be under the threat. Otherwise far eastern plains
may end up being too cool and stable for much more than isolated
rain showers Tuesday/Tuesday night. Snow levels Tuesday night look
to stay around 10kft, possibly dropping to 9Kft Wednesday morning.
Higher elevations above 10kft could pick up several inches of wet
snow.
Wednesday looks cool and stable across the plains, but continued
unsettled over the mountains with another round of scattered showers
and thundestorms. Upper ridge will build over the western U.S from
Thursday through next weekend bringing a good warm up for the
region. Still enough moisture for isolated to low end scattered
thunderstorms mainly over the mountains each day. -KT
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1118 PM MDT Sun May 29 2016
VFR conditions expected at taf sites overnight, with light
drainage flows developing by sunrise Mon. Tsra will develop over
the higher terrain after 18z Mon, with a few storms spreading to
lower elevations late in the day. KCOS has the best chance for a
storm during the day, though have included a vcts mention at all
taf sites for a few hrs mid/late afternoon. Main threat with any
storms will be gusty outflow winds, as low levels along I-25 and
and westward will stay fairly dry. Convection will shift east
onto the plains Mon evening, with clearing skies at all taf sites
after 00z.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...KT
AVIATION...PETERSEN
[top]
Area Forecast Discussion
National Weather Service Grand Junction CO
445 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday night)
Issued at 303 PM MDT Sun May 29 2016
Split troughy pattern over the Rockies will progress eastward
over the next couple of days. The southern closed low trekking
across SoCal today will allow for some added instability late
Monday afternoon and through the night with pieces of energy
pushing in to the northern Four Corners ahead of the unstable air
mass. As mentioned in the previous forecast discussion overall
the models have downscaled activity for Monday afternoon, but
with the vort kickers and ever so slightly increased bulk shear I
would expect more activity than today. High and low temperatures
will remain around normal over the next few days.
.LONG TERM...(Tuesday through Sunday)
Issued at 303 PM MDT Sun May 29 2016
The closed low will stall over Arizona, propagate southward,
and stay south of our forecast area through Wednesday before it
weakens. During this time frame, afternoon convection should stay
anchored over the higher terrain for the most part. In the
meantime, 500 mb heights strengthen high pressure over the
western US and qill slowly shift its axis over eastern Utah and
western Colorado by next weekend. Summer-like weather will truly
show up late this week and next weekend as temperatures soar into
the 90s across the lower valleys and into the upper 60s in the
high mountains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 439 PM MDT Sun May 29 2016
Scattered showers and thunderstorms will continue across the area
through about 03z this evening. Storms will be focused most
strongly over the mountains of western CO and northeast Utah. The
strongest cells will be capable producing outflow winds to 40 MPH
and will briefly obscure mountains. Brief MVFR vsbys and ils cigs
are possible at kase...kege...kril...ktex and kvel. After 03z
storms will dissipate and winds will transition to light and
terrain driven. Similar shower and thunderstorms development is
expected after 17Z Monday.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...JAM
LONG TERM...JAM
AVIATION...CC
Area Forecast Discussion
National Weather Service Grand Junction CO
1036 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1036 MDT Sun May 29 2016
VFR conditions will prevail at airports across eastern Utah and
western Colorado through the next 24 hours. However, daytime
warming and residual moisture will combine to generate scattered
showers and thunderstorms over the higher terrain from 18Z through
03Z this evening. The strongest cells will be capable producing
outflow winds to 35 MPH and will briefly obscure mountains.
Otherwise, winds will be relatively light and terrain driven.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...NL
[top]
Area Forecast Discussion
National Weather Service Denver/Boulder CO
351 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today and tonight)
Issued at 351 AM MDT Sun May 29 2016
Westerly flow aloft will become southerly later today and tonight
as an upper level low moves across southern California. Water
vapor satellite imagery is showing a weak short wave trough over
southwest New Mexico. Models show this wave lifting northeast
through the day. This wave may help trigger storms over southern
parts of the area. Airmass becomes unstable again this afternoon
with CAPE values up to 1000 J/kg. Could see slightly higher values
over the eastern plains if more moisture advects into the area.
Overall, expect similar thunderstorm coverage as yesterday, mainly
scattered storms. There will be a little better chance for hail
with the storms today because of the increased CAPE. However CAPE
and shear will be on lower side, so not expecting severe storms.
However, can`t rule out one or two storms just reaching severe
threshold over the eastern plains. As far as temperatures go,
highs will be 2 to 6 degrees warmer today.
.LONG TERM...(Monday through Saturday)
Issued at 351 AM MDT Sun May 29 2016
Low amplitude upper level ridge shifts east of Colorado on Monday
allowing a long wave upper trough to pass over the region Monday
night and Tuesday. The closed low associated with this trough over
western Arizona is forecast to weaken as it tracks slowly
southeast towards the U.S./Mexico border...while the upper low
over western Montana is projected to gain strength as its drops
southeast clipping nern Wyoming along the way. Monday should start
out dry and mild across the CWA with near zonal flow aloft. Then
as temperatures quickly warm should see scattered showers/t-storms
blossoming over the high terrain around midday. Should see some
of this convection carried off the Front Range during the
afternoon tied to a weak disturbance embedded in the wly flow
aloft. By evening could see some intensification in these t-storms
as they advance into higher dewpts and steeper lapse rates across
far eastern sections of the CWA. Cannot rule out a few hail and
heavy rain producers in this area during the evening hours.
As the northern low passes to our north Monday night...northerly
flow on its back side drives a cold front through nern Colorado
during the pre-dawn hours. Synoptic scale forcing for ascent
appears weak with the upper trough...however during the day
Tuesday models show a deepening northeasterly/upslope flow on the
plains producing a heavy cloud cover and cooler temperatures as
well as areas of light precip. Most of this showery precip is
expected to fall east of the Continental Divide late Monday night
and much of Tuesday with 12-hour precip totals generally a
quarter inch or less. Could see locally heavier amounts in the
foothills to the west and southwest of Denver. Farther out on the
plains...amounts anywhere from a trace to a tenth of an inch.
High temperatures go from around average on Monday to as much as
10-12 degs f below average on Tuesday...with the greatest cooling
likely to occur east of the Cont Dvd.
Tuesday night and beyond...the upper trough shifts over the
northern Great Plains allowing an upper level ridge to gain
strength over the Great Basin. Models show this building ridge
with its warmer temperatures and drier air migrating eastward over
Colorado by Friday. Should see a significant reduction in cloud
cover and limited chances for showers/t-storms with its arrival.
Guidance indicates highs both days in the low to mid-80s on the
plains of northeast Colorado.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 351 AM MDT Sun May 29 2016
Scattered thunderstorms are expected to form over the higher
terrain and spread eastward through the afternoon and evening.
Best time for thunderstorms in the Denver area is 21z-01z. Will go
with a PROB30 in the TAFs at this time. The storms will be capable
of heavy rain, small hail and wind gusts to 35 knots. Winds will
generally be southerly today at KDEN, except when outflow winds
from showers and storms occur.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Meier
Area Forecast Discussion
National Weather Service Grand Junction CO
322 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
&&
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 321 AM MDT Sun May 29 2016
Visual Flight Rules will dominate the forecast over the next 24
hours at the forecast terminals. Instability from heating of the
day and residual moisture will again lead to isolated and
scattered thunderstorm development over the region...favoring the
higher terrain. Gusty outflow winds to 40 mph will be more of a
threat than heavy rainfall...therefor probabilities are quite low
for VFR conditions to be compromised. ILS break points may be
temporary met by passing showers at the KASE KRIL and KEGE
terminals.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
827 PM MDT SAT MAY 28 2016
.UPDATE...
Issued at 825 PM MDT Sat May 28 2016
Still some decent storms on the plains, mainly in pockets of
untapped air. Activity is decreasing overall. I will need to add
some low pops to the northeast corner for a few hours after
midnight in case the current activity around Greeley persists or
there is the redevelopment that the HRRR has been showing on weak
outflows coming back in from the northeast. Already added in the
evening showers over the mountains but these should be much less
by midnight. Rest of the forecast is looking good.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 321 PM MDT Sat May 28 2016
Have seen isolated-scattered showers and a few thunderstorms form
over the mountains and drift eastward out onto the plains over the
past couple hours. Should continue seeing this activity for a few
more hours. Brief heavy rains and small hail will be the main
threats through the early evening. Loss of daytime heating through
the evening will allow showers to come to an end by mid-evening.
Weak westerly flow aloft will continue over the state again on
Sunday, with enough moisture and instability for showers to
develop over the mountains and move over the plains. Model
soundings show CAPE values over 2000 j/kg, so there should be a
bit more strength to the showers that develop. Winds aloft will be
weak, so the threat of locally heavier rain will increase.
Precipitable water values are also forecast to be above .75 inches
late in the afternoon and early evening.
The GFS and ECMWF models are not as wet as the NAM solutions, so
will temper the PoPs back a little bit across the northeast
Colorado plains, in case the shower activity remains in and near
the foothill areas. Otherwise, temperatures will be around
seasonal normals.
.LONG TERM...(Sunday night through Saturday)
Issued at 321 PM MDT Sat May 28 2016
There is weak west-southwesterly flow aloft progged for the
forecast area Sunday night and Monday. By Monday night well into
Tuesday...an upper trough will move into Colorado and the CWA. The
flow aloft stays weak. By 12z Tuesday morning, the upper trough is
through and there is northwesterly flow aloft. There is weak
upward QG motion in the synoptic scale Sunday night into Tuesday
evening, before downward motion moves in by 12z Wednesday morning.
The boundary layer flow will likely adhere to normal diurnal
patterns Sunday night through Monday evening. Models show a decent
cold front with north-northeasterly upslope winds behind it moving
down across the plains and foothills from 06Z to 09Z. The upslope
is progged to continue all day Tuesday and Tuesday night. For
moisture, there is quite a bit over all the CWA through Tuesday
evening, then it decreases overnight. There is fairly decent cape
progged for much of the CWA Sunday evening and late day Monday.
The only decent cape for late day Tuesday is over the mountains
and foothills. The lapse rates are pretty steep much of the time,
except for the plains on Tuesday. It looks somewhat stable behind
the front in the upslope. The best QPF coverage for the CWA is
progged for late day Monday. There are decent amounts of
measurable rainfall in the mountains late day Tuesday as well. for
pops...will go with 30-60%s in the mountains Sunday evening, late
day Monday and late day Tuesday. The plains will have 10-40%s for
those three periods. For temperatures, Monday`s highs are 0-2 C
warmer than Sunday`s highs. Tuesday`s readings are 2-6 C colder
than Monday`s. For the later days, Wednesday through Saturday,
models have northwesterly flow aloft for the forecast area, with
an upper ridge to our west moving towards Colorado. The ridge axis
stays west of our state over Utah through Saturday. The airmass
over the CWA dries out quite a bit and warms up to slightly above
normal temperatures by Friday and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 825 PM MDT Sat May 28 2016
VFR through Sunday. Still some showers and thunderstorms around
mainly east of Denver for the next couple of hours, but very low
chance of anything affecting the Denver area terminals. Widely
scattered storms expected again late Sunday afternoon with short
lived impacts of heavy rain, small hail, and wind gusts to 40
knots possible with some of the storms.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Gimmestad
SHORT TERM...Dankers
LONG TERM...RJK
AVIATION...Gimmestad
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
607 AM CDT MON MAY 30 2016
...AVIATION UPDATE...
.SHORT TERM...(Today and Tonight)
Issued at 256 AM CDT MON MAY 30 2016
08Z water vapor imagery shows little chance to the overall pattern
from 24 hours ago. There is still an upper low over southern CA and
an upper trough moving across the northern Rockies leaving somewhat
zonal and relatively weak flow over KS. At the surface, high
pressure remains over the southern MS river valley with low
pressure along the lee of the Rockies. This is allowing for a moist
airmass to remain over the central plains.
A conditionally unstable airmass is expected once again this
afternoon with temps warming into the lower and mid 80s while
dewpoints remain in the mid 60s. This should be good for CAPE values
around 2000 J/kg. However 0-6 KM shear remains weak given the weak
synoptic flow over the region. So once again the weather will be
driven more by mesoscale features, and confidence of where exactly
forcing or lift for storms will come from is low. With this in mind,
have 30 to 40 percent POPs through the afternoon for possible
scattered convection. If storms are able to form, they will once
again pose a risk for hail as there looks to be plenty of
instability (although the NAM looks to be overdone with dewpoints
and hence the CAPE prog). But organized severe storms would be
limited by the weak deep layer shear. Highs this afternoon are based
on the RAP and NAM forecast soundings mixing the boundary layer to
around 800MB and yesterdays highs making the upper 80s in some
locations. If cloud cover is limited to the afternoon, the forecast
could again be a degree or two on the cool side.
Any afternoon convection should fall apart this evening with the
stabilization of the boundary layer. Although models show a
shortwave and frontal boundary moving into north central KS during
the early morning hours Tuesday. The addition of some dynamics to
the moist airmass should only increase chances for precip. And with
most guidance showing showers and thunderstorms along the frontal
boundary, the forecast has increasing POPs after 06Z from northwest
to southeast across the forecast area. There does not appear to be a
significant wind shift with any cold air advection until after 12Z
Tuesday. Therefore lows are expected to be mild as southerly low
level flow maintains a moist airmass. So have lows in the lower and
middle 60s. The one caveat would be if a decent cold pool formed
from convection with the front. This could cause lows to be several
degrees cooler. Later shifts can look at this again.
.LONG TERM...(Tuesday through Sunday)
Issued at 256 AM CDT MON MAY 30 2016
On Tuesday, the mid level shortwave trough enters the western high
plains. A cold front extending southward will push east through the
region, providing the convergence and lift for widespread convection
throughout the day. Timing from guidance still varies somewhat
similar to yesterday`s model trends. The NAM appears to be the slow
outlier and the ECMWF/GFS in similar agreement with the heaviest
rainfall being in the afternoon. Ample moisture in place with PWAT
values near 1.65 inches is about 150 percent of normal for this time
of year. Moderate rainfall is likely at times which may produce a
quick inch of rain, in addition to localized flooding and river
flooding. Mid-level winds are not particularly strong, suggesting
this boundary may move a bit slower, increasing the flood potential
especially for north central areas. While shear profiles remain weak
at 15-20 kts, ample instability with steep mid level lapse rates
will support updrafts capable of producing large hail and damaging
wind gusts through early evening.
There may be lingering showers and thunderstorms over east central
Kansas on Wednesday, but these should clear out as dry northwest
flow enters the region. Highs will fall back Wednesday and Thursday
into the 70s with lower humidity values and more comfortable
conditions. Overnight lows will generally be in the 50s under clear
skies. The upper ridge over the western CONUS begins to amplify by
late week, essentially trapping the southern plains under a closed
low and continual rainfall. Dry northwest flow centers over
northeast Kansas where Gulf moisture is cutoff by the southern
system. A mid level trough is progged to track south and east
towards the Great Lakes during this time, dropping another cold
front through for next weekend. Models are still inconsistent on
available moisture and lift as the boundary comes through so have
continued with dry pops.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
Issued at 607 AM CDT MON MAY 30 2016
Have a VFR forecast with no mention of TS for now since there is
low confidence in where afternoon convection might occur. The
patchy ground fog is expected to quickly dissipate this morning
leaving VFR conditions for the rest of the day. Models are hinting
at some possible BR after midnight tonight. The NAM has a tendency
to overdo the boundary layer moisture, so will let later shifts
see if models continue to show low level saturation tonight.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Prieto
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Pueblo CO
1147 AM MDT MON MAY 30 2016
.SHORT TERM...(Today and tonight)
Issued at 343 AM MDT Mon May 30 2016
...Strong to severe thunderstorms possible again this afternoon...
Currently...quiet conditions exist across southern Colorado early
this morning. Radar has indicated a few echoes back over the
continental divide and into the San Luis Valley with a few sprinkles
possible through sunrise. Temperatures are running in the upper 40s
to lower 50s across much of the region.
Today...two upper level disturbances, one over southern Arizona and
one strengthening over the Northern Rockies, will set the stage for
another round of showers and thunderstorms for southern Colorado
this afternoon. The Arizona system will send weak energy and
moisture northward into Colorado, while the northern system sends a
cold front and shortwave trough south into northern Colorado.
The dryline is forecast to set up across far eastern Colorado by mid
afternoon. Models in decent agreement with the set up today, with
showers and thunderstorms firing about 20z along the dryline,
generally east of a La Junta to Kim line. Models are indicating
CAPE values around 2000 j/kg along the Kansas border, however shear
will be lacking and will likely limit the severe potential this
afternoon. That being said, one or two strong to severe storms are
possible, especially over eastern Las Animas into Baca Counties,
with a secondary area favored over Kiowa County. Hail to one inch
in diameter and wind gusts to 60 mph are possible with the strongest
storms.
Elsewhere, showers and thunderstorms are forecast to develop across
the mountains by late morning and spread eastward into the I-25
corridor this afternoon and evening. Small hail, locally moderate
to heavy rainfall and lightning will be the primary threats.
Afternoon high temperatures will reach into the lower to mid 80s
across much of the lower elevations.
Tonight...thunderstorms associated with the dryline are forecast to
track eastward into western Kansas during the evening hours, while
showers and thunderstorms over the mountains and adjacent plains
dissipate through midnight. Any severe threat near the Kansas
border will diminish with sunset and as storms move to the east of
the area. A cold front is forecast to drop south across the plains
by Tuesday morning with a northeasterly wind shift. Models are
hinting that the upslope moist flow behind the front will lead to
shower development over the eastern mountains, Palmer Divide and
Raton Mesa during the early morning hours. Overnight lows will be
slightly cooler with mid to upper 40s for most areas. Mozley
.LONG TERM...(Tuesday through Sunday)
Issued at 343 AM MDT Mon May 30 2016
...Cool and unsettled through Wednesday then warmer and drier...
A disturbance and cold front are poised to impact the area Tuesday
into Wednesday with cooler than average temperatures and decent
chances for precipitation over much of the east. The best chance
for precipitation will come Tuesday afternoon and night as a cold
front descends southward through the plains, sending a strong surge
of upslope flow southward. While previous model runs have had the
main precipitation shield concentrated right along and near the east
slopes of the mountains, gradually progressing southward with time,
the 06Z NAM has now shifted the precipitation maximum eastward
across the plains. Not sure what to think of this. I`m always a
little leary of the intermediate 06Z model runs. Conceptually, with
upslope flow, it makes sense to have the maximum precipitation back
up against the mountains. However, if the precipitation area being
depicted by the models is really more of an MCS type of feature,
then it could conceivably track southeast across the plains, tied
more to convective processes in the atmosphere and not so much tied
to upslope forcing along the terrain. In any event, still a good
chance of rain for many areas of the east late Tuesday and Tuesday
night. I`m just not sure where the maximum precipitation will
occur. Where it does occur, there will be the potential for locally
heavy rain.
Most of the precipitation should be over by Wednesday morning
although some may still be falling over southern areas. However,
this should decrease through the morning. The rest of Wednesday
should be cloudy and cooler than average over the east. By late in
the day, enough instability should build over the mountains for
another round of afternoon and evening storms. However, with more
stable air across the plains, any precipitation coming off of the
mountains will probably not last too long once it starts to head
east.
Thursday through the weekend, a large, warm ridge of high pressure
will build over the western U.S. and northern Rockies. This will
result in a strong warmup across the area as well as decreasing
thunderstorm chances. In fact, the air over the plains will likely
dry enough for only very isolated activity during the period. The
mountains, on the other hand, will see enough lift from the
terrain to generate a little better coverage of storms. A lot of
areas across the lower Arkansas River Valley from the Pueblo area
eastward will probably be up around 90 degrees Friday through the
weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1106 AM MDT Mon May 30 2016
Another round of thunderstorms will be possible over the mountains
and plains today, with KCOS and KALS most likely to be impacted
by TSRA at the terminals. Gusty winds to 40 kts will be the most
likely storm threat, though if storm takes a direct hit on the
terminal could see brief MVFR VIS with brief heavy rainfall. TAFS
will maintain VFR conditions for now. East of KLHX, there will be
a better chance for a few strong to severe thunderstorms with wind
gusts to around 50 kts and hail. A cold front will drop through
the plains tonight with winds increasing from the north at both
KCOS and KPUB between 09z-13z. This will bring in MVFR to local
IFR CIGS for the Palmer Divide region which could spread into the
KCOS area early Monday morning. For now think that northerly
downslope winds off the Palmer should keep stratus to the north of
the taf site. There will be a better chance for -SHRA/-TSRA at
KCOS and KPUB tomorrow with CIGS dropping into the IFR category
Tuesday evening. -KT
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...MOZLEY
LONG TERM...LW
AVIATION...KT
[top]
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1053 AM MDT MON MAY 30 2016
.UPDATE...
Issued at 1053 AM MDT Mon May 30 2016
No need for any changes to the forecast at this time. Satellite
imagery shows a short wave over northwest Colorado at the present
time that will be moving out over the northeast plains during the
afternoon hours. We should start seeing showers develop over the
mountains in the next hour or so. Model soundings are showing
around 1000-2000 j/kg of CAPE this afternoon, with higher values
further to the east. With the higher CAPE values on the far
eastern plains, the strongest storms will develop out there, later
in the evening.
&&
.SHORT TERM...(Today and tonight)
Issued at 403 AM MDT Mon May 30 2016
The forecast area is in between weak short waves at the present
time with mostly clear skies in place. However, the next short
wave moving across Utah will arrive by this afternoon with
increasing clouds and convection. Q-G fields show only slight if
any lift, and most of that skirting by to our North and South.
Nonetheless, satellite data would suggest at least an increase in
mid level moisture so the higher PoPs in the forecast for today
seem reasonable. Should see scattered shower and thunderstorm
coverage develop first in the mountains by late morning and then
spread/develop east across the plains shortly after noon.
Low level moisture appears rather thin early this morning, so
CAPE will likely erode along the Front Range to around 500 J/kg,
while farther east on the plains toward Sterling, Akron, and Limon
CAPE should hold closer to 1000 to perhaps 1500 J/kg keeping
potential for one or two severe storms there. SPC outlook seems to
depict this potential well. Strong gusty winds will be the main
threat due to relatively high based storms and increasing mid
level wind field, along with isolated large hail reports possible
in areas of higher CAPE.
For tonight, cold front will push south across the plains late
this evening. Behind that, shallow and moist upslope regime should
result in areas of stratus along with patchy drizzle or light showers,
and areas of fog where stratus deck runs into the ground - namely
the foothills.
.LONG TERM...(Tuesday through Sunday)
Issued at 403 AM MDT Mon May 30 2016
Upper level trough dropping in from the northwest and moist
post-frontal anticyclonic upslope flow on the plains promises a
cooler...cloudy and wet day Tuesday esply for areas east of the
Continental Divide. Upslope flow on the plains is progged to
be relatively shallow during the day...generally no more than
7000-8000 ft at its greatest depth Tuesday morning. Models show
this shallow upslope flow becoming nearly saturated up against
the Front Range during the morning hours. Without much forcing
aloft or instability...the heavy deck of low clouds pushed up
against the Front Range will probably produce not much more than
light rain and/or drizzle...and even areas of fog during the
morning hours. The fog should be concentrated in the foothills
where visibilities may lower below a mile at times during the
morning. Farther out on the plains the low cloud cover will not as
thick nor as extensive and the chance of precip not as great. High
country areas generally west of the Continental Divide should see
less cloud cover and warmer temperatures on Tuesday...and with
more sunshine a slight chance of t-storms by afternoon. Highs on
the plains expected to be only in the 60s.
Tuesday night and Wednesday...the upper trough shifts east
by nighttime placing the forecast area under northwest flow
aloft. Models show a weak mid-level disturbance embedded in this
flow passing over the CWA during the evening hours. Could see some
enhancement in shower activity including a few t-storms as a
result. After midnight should see drier air spreading down from
Wyoming resulting in gradual clearing from north-to-south by early
Wednesday morning. During the day Wednesday...low-level flow on
the plains turns sely as per models which could lead to isolated
shower/t-storm development over and near the Front Range and
across South Park by early to mid-afternoon. Temps on Wednesday
should be a few degs warmer with the return of sunshine.
Thursday through Sunday...the upper ridge building over the Great
Plains will slowly migrate eastward during the period bringing
warmer temperatures and drier air to the forecast area. The chance
of t-storms should significantly drop off as daytime temperatures
climb several degs above average. Temperature guidance gives highs
in the low to mid-80s for the plains. Can`t see any reason to go
against that.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1053 AM MDT Mon May 30 2016
Will hold onto the forecast of a round of thunderstorms moving
across the Denver area late this afternoon. With a weak upper
level disturbance moving across the area this afternoon, it will
be difficult for thunderstorms to not develop. The storms will be
high-based after moving off the foothills. Gusty winds and brief
rain will be the main threats at the airports.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Dankers
SHORT TERM...Barjenbruch
LONG TERM...Baker
AVIATION...Dankers
Area Forecast Discussion
National Weather Service Pueblo CO
1123 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday)
Issued at 237 PM MDT Sun May 29 2016
...Chance for strong to severe thunderstorms increases for Monday
across the plains...
Embedded shortwave ejecting northeast into CO has fired off showers
and thunderstorms over the mountains. Strongest convection this
afternoon is expected to fire along and east of a dryline across the
far eastern counties. SPC meso analysis shows around 1500-2500 J/kg
across the far southeast counties of eastern Las Animas, Baca and
Prowers counties as of 20z. Effective bulk shears will be running
around 30-40 kts, especially if sfc winds can shift a bit
southeasterly, so potential exists for an isolated severe
thunderstorm through the early evening. Otherwise, expect isolated
to scattered showers and thunderstorms with some small hail and
gusty winds possible. Thunderstorms should diminish overnight.
Monday will be a similar set up to today. Upper low over SW CA will
move eastward into AZ, at the same time a northern stream upper trof
drops into the northern U.S. Rockies. With approach of these
systems, suspect sfc winds will stay more southeasterly on Monday
which may serve to keep 40s to mid 50 sfc dew points across the
southeast plains to the north of a sfc boundary which will run along
the highway 50 corridor, southeastward to Kim by afternoon. Mid
level winds look a little weak, which may limit deep layer shear
some. But with CAPES running from 800-2000+ J/KG, this could lead to
a couple severe thunderstorms again Monday afternoon. Best threat
area will be to the east of La Junta, but depending on how much
low level moisture can be maintained farther west, its possible
that portions of El Paso county could see a strong to severe
thunderstorm Monday afternoon as well. Highest pops will be
across the mountains, El Paso county and the far eastern plains
Monday afternoon.
.LONG TERM...(Monday night through Sunday)
Issued at 237 PM MDT Sun May 29 2016
...Wet weather for Tuesday/Tuesday Night for SE Mountains/Adjacent
Plains...
Upper low across MT/WY will move eastward into the Dakotas by Tues
morning while trailing trof/upper low slowly meanders eastward over
AZ. Northern stream system will drop a cold front through the
southeast plains Monday night/Tuesday morning, though initially
appears northerly surge will be influenced more by convective
outflows from thunderstorms along the Palmer Divide and northeast
CO, with cooler air lagging until late Monday night/Tuesday
morning. Will keep thunderstorms going across the southeast plains
as there will probably be enough convergence along the boundary
for thunderstorm initiation. Best chance for any severe
thunderstorms Monday evening will be east of La Junta again where
deeper moisture will reside. Could also see a strong storm or two
along the Palmer Divide, but this will depend on how much low
level moisture is maintained.
Models in better agreement on Tuesday, driving the front well
southward into NE NM by 18z Tues. Should see upslope
showers/thunderstorms develop over the southeast mountains fairly
early in the day. However, suspect that Northerly surface winds will
also send some modestly drier air into the southeast plains during
the afternoon. Theta E ridge/axis of higher dew points will
likely reside across NE NM/TX Panhandle region, along and north
of the frontal boundary. Still plenty of moisture/instability over
the mountain, particularly the SE Mts, for fairly widespread
showers and thunderstorms on Tuesday. Could be a strong storm or
two over the mountains as well though think CAPE is overdone in
the NAM. Both NAM and GFS carry precipitation into the overnight
hours across the southeast mountains/adjacent plains, though 12z
GFS looks convectively contaminated after 06z given its over an
inch bulls eye over the Pikes Peak region and Wet mountains. More
likely scenario will be for focus to be shifting southward along
the SE Mts/I-25 corridor during the overnight hours with Wets and
southern Sangre De Cristo mountains seeing max precipitation
during the overnight hours. Main concern besides a strong to
marginally severe storm or two Tuesday afternoon will be the
potential for heavy rainfall on area burn scars. NE flow would
tend to favor the Wets and Sangres for this risk...but Waldo burn
scar will also be under the threat. Otherwise far eastern plains
may end up being too cool and stable for much more than isolated
rain showers Tuesday/Tuesday night. Snow levels Tuesday night look
to stay around 10kft, possibly dropping to 9Kft Wednesday morning.
Higher elevations above 10kft could pick up several inches of wet
snow.
Wednesday looks cool and stable across the plains, but continued
unsettled over the mountains with another round of scattered showers
and thundestorms. Upper ridge will build over the western U.S from
Thursday through next weekend bringing a good warm up for the
region. Still enough moisture for isolated to low end scattered
thunderstorms mainly over the mountains each day. -KT
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1118 PM MDT Sun May 29 2016
VFR conditions expected at taf sites overnight, with light
drainage flows developing by sunrise Mon. Tsra will develop over
the higher terrain after 18z Mon, with a few storms spreading to
lower elevations late in the day. KCOS has the best chance for a
storm during the day, though have included a vcts mention at all
taf sites for a few hrs mid/late afternoon. Main threat with any
storms will be gusty outflow winds, as low levels along I-25 and
and westward will stay fairly dry. Convection will shift east
onto the plains Mon evening, with clearing skies at all taf sites
after 00z.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...KT
AVIATION...PETERSEN
[top]
Area Forecast Discussion
National Weather Service Grand Junction CO
445 PM MDT SUN MAY 29 2016
.SHORT TERM...(This evening through Monday night)
Issued at 303 PM MDT Sun May 29 2016
Split troughy pattern over the Rockies will progress eastward
over the next couple of days. The southern closed low trekking
across SoCal today will allow for some added instability late
Monday afternoon and through the night with pieces of energy
pushing in to the northern Four Corners ahead of the unstable air
mass. As mentioned in the previous forecast discussion overall
the models have downscaled activity for Monday afternoon, but
with the vort kickers and ever so slightly increased bulk shear I
would expect more activity than today. High and low temperatures
will remain around normal over the next few days.
.LONG TERM...(Tuesday through Sunday)
Issued at 303 PM MDT Sun May 29 2016
The closed low will stall over Arizona, propagate southward,
and stay south of our forecast area through Wednesday before it
weakens. During this time frame, afternoon convection should stay
anchored over the higher terrain for the most part. In the
meantime, 500 mb heights strengthen high pressure over the
western US and qill slowly shift its axis over eastern Utah and
western Colorado by next weekend. Summer-like weather will truly
show up late this week and next weekend as temperatures soar into
the 90s across the lower valleys and into the upper 60s in the
high mountains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 439 PM MDT Sun May 29 2016
Scattered showers and thunderstorms will continue across the area
through about 03z this evening. Storms will be focused most
strongly over the mountains of western CO and northeast Utah. The
strongest cells will be capable producing outflow winds to 40 MPH
and will briefly obscure mountains. Brief MVFR vsbys and ils cigs
are possible at kase...kege...kril...ktex and kvel. After 03z
storms will dissipate and winds will transition to light and
terrain driven. Similar shower and thunderstorms development is
expected after 17Z Monday.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...JAM
LONG TERM...JAM
AVIATION...CC
Area Forecast Discussion
National Weather Service Grand Junction CO
1036 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1036 MDT Sun May 29 2016
VFR conditions will prevail at airports across eastern Utah and
western Colorado through the next 24 hours. However, daytime
warming and residual moisture will combine to generate scattered
showers and thunderstorms over the higher terrain from 18Z through
03Z this evening. The strongest cells will be capable producing
outflow winds to 35 MPH and will briefly obscure mountains.
Otherwise, winds will be relatively light and terrain driven.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...NL
Area Forecast Discussion
National Weather Service Denver/Boulder CO
351 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today and tonight)
Issued at 351 AM MDT Sun May 29 2016
Westerly flow aloft will become southerly later today and tonight
as an upper level low moves across southern California. Water
vapor satellite imagery is showing a weak short wave trough over
southwest New Mexico. Models show this wave lifting northeast
through the day. This wave may help trigger storms over southern
parts of the area. Airmass becomes unstable again this afternoon
with CAPE values up to 1000 J/kg. Could see slightly higher values
over the eastern plains if more moisture advects into the area.
Overall, expect similar thunderstorm coverage as yesterday, mainly
scattered storms. There will be a little better chance for hail
with the storms today because of the increased CAPE. However CAPE
and shear will be on lower side, so not expecting severe storms.
However, can`t rule out one or two storms just reaching severe
threshold over the eastern plains. As far as temperatures go,
highs will be 2 to 6 degrees warmer today.
.LONG TERM...(Monday through Saturday)
Issued at 351 AM MDT Sun May 29 2016
Low amplitude upper level ridge shifts east of Colorado on Monday
allowing a long wave upper trough to pass over the region Monday
night and Tuesday. The closed low associated with this trough over
western Arizona is forecast to weaken as it tracks slowly
southeast towards the U.S./Mexico border...while the upper low
over western Montana is projected to gain strength as its drops
southeast clipping nern Wyoming along the way. Monday should start
out dry and mild across the CWA with near zonal flow aloft. Then
as temperatures quickly warm should see scattered showers/t-storms
blossoming over the high terrain around midday. Should see some
of this convection carried off the Front Range during the
afternoon tied to a weak disturbance embedded in the wly flow
aloft. By evening could see some intensification in these t-storms
as they advance into higher dewpts and steeper lapse rates across
far eastern sections of the CWA. Cannot rule out a few hail and
heavy rain producers in this area during the evening hours.
As the northern low passes to our north Monday night...northerly
flow on its back side drives a cold front through nern Colorado
during the pre-dawn hours. Synoptic scale forcing for ascent
appears weak with the upper trough...however during the day
Tuesday models show a deepening northeasterly/upslope flow on the
plains producing a heavy cloud cover and cooler temperatures as
well as areas of light precip. Most of this showery precip is
expected to fall east of the Continental Divide late Monday night
and much of Tuesday with 12-hour precip totals generally a
quarter inch or less. Could see locally heavier amounts in the
foothills to the west and southwest of Denver. Farther out on the
plains...amounts anywhere from a trace to a tenth of an inch.
High temperatures go from around average on Monday to as much as
10-12 degs f below average on Tuesday...with the greatest cooling
likely to occur east of the Cont Dvd.
Tuesday night and beyond...the upper trough shifts over the
northern Great Plains allowing an upper level ridge to gain
strength over the Great Basin. Models show this building ridge
with its warmer temperatures and drier air migrating eastward over
Colorado by Friday. Should see a significant reduction in cloud
cover and limited chances for showers/t-storms with its arrival.
Guidance indicates highs both days in the low to mid-80s on the
plains of northeast Colorado.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 351 AM MDT Sun May 29 2016
Scattered thunderstorms are expected to form over the higher
terrain and spread eastward through the afternoon and evening.
Best time for thunderstorms in the Denver area is 21z-01z. Will go
with a PROB30 in the TAFs at this time. The storms will be capable
of heavy rain, small hail and wind gusts to 35 knots. Winds will
generally be southerly today at KDEN, except when outflow winds
from showers and storms occur.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Meier
Area Forecast Discussion
National Weather Service Grand Junction CO
322 AM MDT SUN MAY 29 2016
.SHORT TERM...(Today through Monday)
Issued at 321 AM MDT Sun May 29 2016
A pair of troughs organizing over the western NOAM in British
Columbia and just off the central California coast. Shortwave
ridging extends across the southern Rockies and 4 Corners region
where it will persist through the day. The stronger northern
stream wave will begin to swing westward and dig into the northern
Rockies states through the short term period...which will help
drag the southern system off the coast and into the Desert
Southwest. This split pattern is not favorable for strong ascent
to move over our CWA and this will keep afternoon showers and
thunderstorms isolated to scattered the next few days. Some weak
ascent is moving across our southern tier of zones this morning as
the sub-trop jet is lifting across the Baja into the Southern
Plains. Feel forecast is in good shape with no major changes at
this time. Temperatures should warm very close to normal both
today and Monday afternoon. There could be a small uptick in
convection on Monday as the two system briefly phase...but for the
most part models trends have been for a downturn in precipitation
coverage for Monday afternoon.
&&
.LONG TERM...(Monday night through Saturday)
Issued at 321 AM MDT Sun May 29 2016
The persistent southwest flow will continue to carry modest
moisture into the region through Tuesday. Behind these features, a
ridge of high pressure will develop along the west coast early in
the work week and then move into the Great Basin by midweek. This
high pressure center will continue to strengthen and will remain
to our west through the end of the period. As a result,
temperatures will top out a few degrees above normal late in the
week. Less, but sufficient moisture will remain over the region
for a slight chance of mainly mountain showers and thunderstorms
each afternoon into next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 321 AM MDT Sun May 29 2016
Visual Flight Rules will dominate the forecast over the next 24
hours at the forecast terminals. Instability from heating of the
day and residual moisture will again lead to isolated and
scattered thunderstorm development over the region...favoring the
higher terrain. Gusty outflow winds to 40 mph will be more of a
threat than heavy rainfall...therefor probabilities are quite low
for VFR conditions to be compromised. ILS break points may be
temporary met by passing showers at the KASE KRIL and KEGE
terminals.
&&
.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...EH
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
827 PM MDT SAT MAY 28 2016
.UPDATE...
Issued at 825 PM MDT Sat May 28 2016
Still some decent storms on the plains, mainly in pockets of
untapped air. Activity is decreasing overall. I will need to add
some low pops to the northeast corner for a few hours after
midnight in case the current activity around Greeley persists or
there is the redevelopment that the HRRR has been showing on weak
outflows coming back in from the northeast. Already added in the
evening showers over the mountains but these should be much less
by midnight. Rest of the forecast is looking good.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 321 PM MDT Sat May 28 2016
Have seen isolated-scattered showers and a few thunderstorms form
over the mountains and drift eastward out onto the plains over the
past couple hours. Should continue seeing this activity for a few
more hours. Brief heavy rains and small hail will be the main
threats through the early evening. Loss of daytime heating through
the evening will allow showers to come to an end by mid-evening.
Weak westerly flow aloft will continue over the state again on
Sunday, with enough moisture and instability for showers to
develop over the mountains and move over the plains. Model
soundings show CAPE values over 2000 j/kg, so there should be a
bit more strength to the showers that develop. Winds aloft will be
weak, so the threat of locally heavier rain will increase.
Precipitable water values are also forecast to be above .75 inches
late in the afternoon and early evening.
The GFS and ECMWF models are not as wet as the NAM solutions, so
will temper the PoPs back a little bit across the northeast
Colorado plains, in case the shower activity remains in and near
the foothill areas. Otherwise, temperatures will be around
seasonal normals.
.LONG TERM...(Sunday night through Saturday)
Issued at 321 PM MDT Sat May 28 2016
There is weak west-southwesterly flow aloft progged for the
forecast area Sunday night and Monday. By Monday night well into
Tuesday...an upper trough will move into Colorado and the CWA. The
flow aloft stays weak. By 12z Tuesday morning, the upper trough is
through and there is northwesterly flow aloft. There is weak
upward QG motion in the synoptic scale Sunday night into Tuesday
evening, before downward motion moves in by 12z Wednesday morning.
The boundary layer flow will likely adhere to normal diurnal
patterns Sunday night through Monday evening. Models show a decent
cold front with north-northeasterly upslope winds behind it moving
down across the plains and foothills from 06Z to 09Z. The upslope
is progged to continue all day Tuesday and Tuesday night. For
moisture, there is quite a bit over all the CWA through Tuesday
evening, then it decreases overnight. There is fairly decent cape
progged for much of the CWA Sunday evening and late day Monday.
The only decent cape for late day Tuesday is over the mountains
and foothills. The lapse rates are pretty steep much of the time,
except for the plains on Tuesday. It looks somewhat stable behind
the front in the upslope. The best QPF coverage for the CWA is
progged for late day Monday. There are decent amounts of
measurable rainfall in the mountains late day Tuesday as well. for
pops...will go with 30-60%s in the mountains Sunday evening, late
day Monday and late day Tuesday. The plains will have 10-40%s for
those three periods. For temperatures, Monday`s highs are 0-2 C
warmer than Sunday`s highs. Tuesday`s readings are 2-6 C colder
than Monday`s. For the later days, Wednesday through Saturday,
models have northwesterly flow aloft for the forecast area, with
an upper ridge to our west moving towards Colorado. The ridge axis
stays west of our state over Utah through Saturday. The airmass
over the CWA dries out quite a bit and warms up to slightly above
normal temperatures by Friday and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 825 PM MDT Sat May 28 2016
VFR through Sunday. Still some showers and thunderstorms around
mainly east of Denver for the next couple of hours, but very low
chance of anything affecting the Denver area terminals. Widely
scattered storms expected again late Sunday afternoon with short
lived impacts of heavy rain, small hail, and wind gusts to 40
knots possible with some of the storms.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Gimmestad
SHORT TERM...Dankers
LONG TERM...RJK
AVIATION...Gimmestad
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
243 PM CDT MON MAY 30 2016
.SHORT TERM...(This afternoon through Tuesday)
Issued at 243 PM CDT Mon May 30 2016
Our focus is on the potential for severe thunderstorms through
this evening, especially in south central ND.
The 18 UTC Bismarck sounding sampled relatively steep mid-level
lapse rates near 7.5 C/km, contributing to MLCAPE around 1000 J/kg
despite increasing cloud cover. The sounding also revealed 0-6-km
bulk wind shear just over 30 kt, sufficient for organized storms,
but likely favoring multi-cellular modes, especially given a small
weakness in the wind fields just above 700 MB. The 19 UTC surface
analysis places a surface low just north of Bismarck, with a warm
front extending east of the low from near Washburn to Carrington,
and a cold front south across central Morton and Grant Counties.
That demarcates the severe risk going forward, as supported by
recent convection-allowing model guidance. The 18 UTC sounding
revealed an uncapped air mass, and as a result convection and the
related cloud cover is still posing some issues to the potential
for severe convection. However, very recent visible satellite
imagery shows clearing over Grant County near the cold frontal
zone, which may enable more intense updrafts to form in the next
hour or two. That`s in line with convection-allowing model output
that still suggests a line of storms with hail and wind potential
will move eastward near and south of I-94 from around Bismarck to
Jamestown between 20 and 03 UTC.
On Tuesday, the low pressure system will have occluded and the
surface to 500 MB circulation is forecast to become stacked in
north central ND. Showers and embedded, non-severe storms are
simulated by guidance to be wrapping around the north and west
sides of the stacked low, impacting much of western and north
central ND. There is some uncertainty in the southward extent
of the shower activity, with the ECMWF and 12 UTC NAM slightly
more robust with QPF to the south of Highway 200 than the GFS.
Nonetheless, those models are in relatively good agreement and
a blend of them supports widespread PoPs over 60 percent over
much of western and central ND, save for across the southern
James River valley where a mid-level dry slot will be in play.
Note that there is still a non-zero risk of weak funnels near
the stacked low over north central ND, but diagnostic output
from the 12 UTC guidance suggests that the low-level CAPE-VGP
setting will not favor cold core tornadoes. Conceptually, the
stacked low scenario doesn`t favor cold core tornadoes, either,
as it reduces low-level baroclinicity and vorticity somewhat.
.LONG TERM...(Tuesday night through Sunday)
Issued at 243 PM CDT Mon May 30 2016
Lingering shower activity will gradually end Tuesday night and
early Wednesday as the stacked low pressure system slowly moves
east-northeast into southwest Ontario. The 12 UTC models are in
relatively good agreement suggesting that mid-level flow should
lose its cyclonic nature during the day Wednesday as that low
departs and 500-MB heights rise a bit in its wake. There may be
a low-end shower potential in central ND until those heights do
begin rising by afternoon, but confidence in any showers is low.
The key message we want to convey in the long term is a warming
trend that will commence by late week. The multi-model consensus
calls for highs to warm from the 60s F on Wednesday to the 70s F
Thursday, and upper 70s and lower 80s F Friday through Monday as
a stout 500-MB ridge takes shape over the intermountain west and
exerts its influence downstream across the northern Plains. The
deterministic and ensemble guidance displays low spread with the
ridge axis, but the amplitude of downstream flow differs, as the
00 and 06 UTC GFS simulations are generally deeper with a low in
the Great Lakes region by late weekend. A deeper low would favor
greater potential for somewhat cooler air to be advected into ND
in the general northwest flow aloft. CIPS analogs applied to the
00 UTC GFS ensemble reflect that possibility, offering no strong
signal as to whether temperatures will be above or below normal.
However, the non-GFS guidance supports less amplitude to the low
over the Great Lakes, favoring the warmer regime that`s also the
main influence on our blended-model-driven forecast. CIPS analog
output strongly favors below-normal precipitation in the period
centered on this weekend, especially in western ND, so we have a
mainly dry forecast in play. However, the 00 and 12 UTC GFS and
NAM, and to a somewhat lesser extent the ECMWF, suggest that a
mid-level shortwave trough will cross the region Thursday night
and Friday, offering some shower and thunderstorm potential in
that time frame.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 243 PM CDT Mon May 30 2016
Widespread showers and thunderstorms will spread east out of
western and across central ND this afternoon and evening. Local
MVFR to IFR conditions are expected. Some storms may be severe
with large hail and damaging winds southwest and south central.
Widespread showers and embedded thunderstorms will continue into
Tuesday. MVFR to IFR ceilings are likely Tuesday in northwest and
north central ND, and they are possible over southwest and south
central ND, too.
&&
.BIS Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...CJS
[top]
Area Forecast Discussion
National Weather Service Grand Forks ND
638 AM CDT MON MAY 30 2016
.UPDATE...
Issued at 635 AM CDT Mon May 30 2016
No significant changes made this update period.
&&
.SHORT TERM...(Today through Tuesday)
Issued at 200 AM CDT Mon May 30 2016
forecast concerns will be severe potential tonight and rain
duration. Models still differ on surface low position however high
resolution models supporting farther north solution. Otherwise
overall message similar with severe potential tonight.
Today will start out sunny with increasing southerly flow/moisture
flux during the afternoon. Surface low to organize over the
northern high plains and will be location of convective
initiation. Farther south solution would have convection
also developing along E-W boundary along the ND/SD border area
where the northern solution keeps convection farther west. With
model differences there is some uncertainty as to when convection
will reach our FA so did not make significant changes to pops.
Should be sufficient solar along with warm advection to get
temperatures a few degrees warmer than Sunday highs.
Main action will be tonight as surface low and related convection
shifts east into the region. Bulk shear not overly impressive and
best upper support lags back into the western/central dakotas.
However strong low level forcing and sufficient cape/instability
for severe storm threat. Slight risk area expanded north and
justified with some model showing farther north solution.
Surface low will reside over the northern fa on Tuesday. Dry
slotting will limit best rain chances to the northern fa. As a
result coolest temperatures will be across the north with
temperatures close to average across the south.
.LONG TERM...(Tuesday night through Sunday)
Issued at 200 AM CDT Mon May 30 2016
Low becomes stacked Tuesday night across the northern valley
region so only a slow eastward propagation expected. This will
slowly shift wrap around rain band slowly east overnight to the
valley region.
low will pull out Wednesday with best rain chances over the ne fa.
Cooler column and clouds will hold temperatures well blo average.
Wednesday to Saturday night...Models have become consistent
with robust short wave trough moving across the northern plains to
start the extended period. Stacked low pressure system centered over
the valley will bring a cool...damp start to June with clouds and
showers lingering into the afternoon especially in NW MN...highs in
the 60s. Thursday and first half of Friday will be dry as 500mb
ridging and NW flow aloft bring weak high pressure to the
Northern Plains. The next CHC for convection arrives Friday PM
into Saturday as sfc low and upper support track across northern
Manitoba dragging a boundary across the FA.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 635 AM CDT Mon May 30 2016
With exception of BJI which has localized FG, VFR conditions
expected atleast through mid afternoon. Any lower cigs there after
will be associated with TSRA. At this time still some uncertainty
on arrival time.
&&
.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&
$$
UPDATE...Voelker
SHORT TERM...Voelker
LONG TERM...JK/Voelker
AVIATION...Voelker
Area Forecast Discussion
National Weather Service Grand Forks ND
1153 PM CDT SUN MAY 29 2016
.UPDATE...
Issued at 1153 PM CDT Sun May 29 2016
Minimal changes made with this update.
UPDATE Issued at 954 PM CDT Sun May 29 2016
Added a slight chance of showers in far SE ND late tonight/early
tomorrow morning. HRRR and HopWRF tipped the scales to mentioning
something down near the SD border. NAM/GFS have some FGEN in that
area...but limited CAPEs. Just enough to produce a shower or two
on the ND side.
UPDATE Issued at 712 PM CDT Sun May 29 2016
A quiet evening is expected across the forecast area. The latest
HRRR model hints at showers and perhaps a thunderstorm along the
ND/SD border late tonight/early tomorrow morning. The latest NAM
also hints at this although MU-CAPE values supporting elevated
convection stay to the south and west through 12z...except in the
devils lake basin. Will continue with a dry forecast tonight for
now and consider the new NAM and HRRR runs for next update.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 329 PM CDT Sun May 29 2016
Main forecast challenge will be severe potential for areas along
and south of the Interstate 94 corridor on Monday afternoon and
Monday evening. As for tonight, the cumulus field is already
showing signs of thinning. There are a few showers left from
Mahnomen to Detroit Lakes, but these should not last too much
longer. Drier air continues to move in from the west, with the dew
point at KDVL already at 41F. With the drier air moving in, not
expecting fog formation tonight. Monday will start out nice, but
storms will increase over the central or western Dakotas by
afternoon. SPC day 2 outlook has areas along and south of the
Interstate 94 corridor in a marginal risk, with Sargent County ND
in a slight risk. This event still a day away, so confidence not
great at the moment in timing or placement of the tstm
development. There is a lot of variation yet in the models, with
the ECMWF slower than the American models. Thinking that storms
will fire over the western or central Dakotas in the afternoon and
move eastward and affect this FA during the late afternoon or
evening. Models do show good agreement in another widespread pcpn
event, with a good one to two inches for most of the FA. Models
also agree on showing most of the pcpn rotating northward later
Monday night, with drying working into portions of far southeast
ND.
.LONG TERM...(Tuesday through Sunday)
Issued at 329 PM CDT Sun May 29 2016
On Tuesday the dry slot remains over southeast ND and portions of
west central MN, with the main pcpn band along and north of
highway 200. As the sfc low lifts NE Tue night into Wed, the pcpn
will slowly turn to lighter wraparound bands.
For Wed night through Sunday...Surface high will be dropping into
northern valley behind an upper ridge that should dry things out
Wed night and keep it dry on Thursday...with slightly cooler
temperatures generally in the 60s...with lower 70s in southeastern
ND. Return flow then sets up Thu night with a frontal system
moving into the area early Fri morning, bringing a chance for
showers and thunderstorms through Sat morning.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1153 PM CDT Sun May 29 2016
A shower or two may exist south of KFAR around sunrise. There is a
low probablity that any showers would make it as far north as
KFAR. Most should stay closer to the SD border.
Added thunderstorms for Monday night in all TAFs. Expecting a
large area of thunderstorms extending NW to SE generally by
evening. There will likely be MVFR or even IFR cigs beyond this
TAF period, first at KDVL and then moving east.
&&
.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&
$$
UPDATE...Knutsvig
SHORT TERM...Godon
LONG TERM...Godon/Speicher
AVIATION...Knutsvig