Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/29/16
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 Northern Indiana
1032 PM EDT SAT MAY 28 2016
.SYNOPSIS...
Issued at 1032 PM EDT Sat May 28 2016
A weak cold front will move across the area Sunday afternoon and may
spark an isolated shower or thunderstorm otherwise fair weather is
expected for Memorial Day as high pressure builds in behind the
front. Temperatures will remain above normal with highs in the lower
to middle 80s and lows in the lower to middle 60s.
&&
.UPDATE...
Issued at 615 PM EDT Sat May 28 2016
As was the case yda evening...lack of sfc based instability within
poorly defined theta-e ridge alg w/warm temps aloft and lackluster
forcing curtailing more erstwhile conv dvlpmnt. As such and in
reflection of nr term CAMS guidance will truncate extent of prior
pops overnight. Upstream arc of vigorous convn acrs wrn IL will
decay w/ewd extent yet still poses a isold shra threat aft 03Z far
west. Otrws remainder of fcst on track.
&&
.SHORT TERM...(This Evening through Sunday)
Issued at 302 PM EDT Sat May 28 2016
Warm/moist conditions and low chances for showers/storms will
remain the weather story through Sunday afternoon as the region
remains in warm sector. Low chances (20-40%) for widely scattered
showers/isolated thunder into the early evening mainly confined to
northeast IN and northwest OH where nearly 1000 j/kg of SBCAPE is
available for a weak upper wave lifting northeast within mid-level
theta-e plume/LLJ core downstream of a well defined shortwave
tracking into the Upper Midwest. Mainly dry/mild otherwise into
tonight with expectations for convection that fires late afternoon
across Iowa/western Illinois on eastern fringe of Upper Midwest
low pressure system to weaken/fall apart before reaching Indiana.
The northern stream finally gets involved enough to kick
open/weakening Upper Midwest shortwave east into the Great Lakes on
Sunday. This feature will force a cold front southeast into the area
Sunday afternoon bringing additional low chances for convection.
However, there will once again be substantial limiting factors for
more widespread/organized development along this feature as deeper
moisture, more favorable upper level support, and pre-frontal
trough likely exits east by peak heating. There is the potential
for moderate destabilization pre-frontal, but only around 20-25
knots of 0-6 km bulk shear suggest an isolated strong-severe storm
at best if storms initiate.
&&
.LONG TERM...(Sunday Night through Saturday)
Issued at 302 PM EDT Sat May 28 2016
System will exit off to the east in flattened flow leaving weak
boundary over or just south of the local area by Monday
afternoon. Previous model cycles were more aggressive in forcing
cold front south of the area while some of the new 12z guidance
hangs up front/instability gradient over far west/southwest zones.
With lack of any upper level support, drying, and model
differences will not introduce low PoPs for mid-late afternoon
convection Monday. Ridging/drying will likely hang on into early
Tuesday before warm/moist southwest flow becomes reestablished in
advance of the next PV anomaly modeled to drop east-southeast from
the Dakotas-Upper Midwest Wednesday to the Great Lakes by
Thursday-Friday. The best chance for showers/storms per last
several model cycles looks to be later Wednesday into Thursday
with the primary cold frontal passage. Otherwise, temperatures are
expected to remain above normal through Thursday, then trending
closer to normal thereafter.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 126 PM EDT Sat May 28 2016
Sct shra and a few ts expected to develop this aftn as a wk
shrtwv moves rapidly ne from the lwr/mid MS Valley across IN. A
little strong shrtwv expected to move fm w-e across the area
Sunday, but decreasing moisture in advance of the system supports
not adding shra/ts mention to tafs attm. Otrws, vfr conditions
should cont with moderately strong southerly flow grdly veering to
west on Sunday.
&&
.IWX Watches/Warnings/Advisories...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...T
SYNOPSIS...T
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...JT
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Area Forecast Discussion
National Weather Service Indianapolis IN
1006 PM EDT SAT MAY 28 2016
.UPDATE...
The NEAR TERM Section has been updated below.
&&
.SYNOPSIS...
Issued at 325 PM EDT SAT MAY 28 2016
Low pressure over the upper midwest will move east across the northern
great lakes Sunday and trailing cold front will move across our region
late Sunday and Sunday evening. High pressure will bring dry weather
Monday and early Tuesday. An upper low will move towards the great
lakes by the middle of next week and a cold front will move across our
region around Friday.
&&
.NEAR TERM /Rest of Tonight/...
Issued at 1001 PM EDT Sat May 28 2016
UPDATE...
Radar mosaic is currently quiet across most of Central Indiana
except for some rain showers over the eastern counties. Further
west, showers and thunderstorms are moving through Illinois, but
they should weaken by the time they reach Central Indiana. As a
result, will continue to only carry mention of slight chance rain
showers overnight. Current temps across the area are generally in
the low to mid 70s, and overnight lows are expected to be in the
mid 60s. Updated grids have been sent.
PREVIOUS DISCUSSION...
Water vapor satellite indicated plume of moisture from Mississippi and
Alabama north across our region. Showers and thunderstorms were
beginning to develop across our region with day time heating and and
high resolution shows an increase of thunderstorms into the early
evening hour and then diminishing or ending most areas by late evening.
Will mention slight chance POPs west and chance POPS east early this evening
and then thunderstorms ending most areas by midnight. Then a weak upper
disturbance may produce a few light showers late tonight.
Lows tonight will be in the middle 60s which is close to a MOS blend.
&&
.SHORT TERM /Sunday through Tuesday/...
Issued at 325 PM EDT SAT MAY 28 2016
Models have trended drier towards Sunday and most models indicate little if
any precipitation. However with a cold front moving into our region late Sunday
prefer to keep low chance POPS in mainly Sunday afternoon and far east
Sunday evening.
After that weak high pressure will bring a period of dry weather later
Sunday night through early Tuesday. The NAM and GFS models are quicker in spreading
precip our way late Monday and Tuesday. I believe they are too quick given
that weak high pressure will be moving east across our region along with a
weak upper ridge. New European keeps this next area of precipitation farther
west and will lean in that direction. To match up with other offices will add
a slight chance of thunderstorms over northwest sections late Tuesday. Otherwise...
the rest of the short term will be dry.
Models keep 850 MB temperatures in the lower to middle teens and with more sunshine
high temperatures will be a little warmer with highs in the middle 80s. With
mostly clear skies and light winds lows will be in the lower 60s Sunday night and
lower to middle 60s Monday night. In most cases stayed close to a MOS blend on
temperatures.
&&
.LONG TERM /Tuesday Night through Saturday/...
Issued at 159 PM EDT Sat May 28 2016
ECMWF continue to keeps the warm and humid air mass in place
across central Indiana through Thursday. Thus as superblend
suggests...kept low chance pops in place during that time to
account for diurnal showers and storms.
Best chances for rain look to be on Thursday afternoon and evening
as the ECMWF shows a cold front crossing Indiana from the
northwest. With ample moisture in place ahead of the
front...precipitation seems like a good bet here.
Superblend continued to keep low chance pops in the forecast on
Friday and Saturday. The ECMWF shows the cold front southeast of
Indiana at that time...along with subsidence in place along with a
cooler and dryer air mass in place amid NW flow. Therefore we
twiddled the pop grids down 5-10% to achieve a dry forecast then.
&&
.AVIATION /Discussion for 290000z TAF issuance/...
Issued at 714 PM EDT Sat May 28 2016
A brief light shower could move over KIND over the next hour but
this shouldn`t cause any flight reductions. Later tonight could
see some MVFR fog develop at the outlying sites after around 8-9z
with ample low level moisture available and winds dropping off to
around 5 kts or less. Some cloud cover should keep things from
dropping off too much. Hi res models are showing the line of
thunderstorms currently over Illinois and stretching south into
Missouri weakening and scattering out before it gets to Indiana
and as a result will leave this out. Will again have some chances
for thunderstorms Sunday especially during the afternoon ahead of
the cold frontal passage making it more likely at KIND and KBMG.
More likely in this case though still means a 30 percent chance or
less of hitting either site so will leave out for now. Forecast
soundings show some potential for wind gusts around 14-20 kts out
of the west generally in the wake of the frontal passage.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...TDUD
SHORT TERM...JH
LONG TERM....PUMA
AVIATION...CP
Area Forecast Discussion
National Weather Service Indianapolis IN
722 PM EDT SAT MAY 28 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 325 PM EDT SAT MAY 28 2016
Low pressure over the upper midwest will move east across the northern
great lakes Sunday and trailing cold front will move across our region
late Sunday and Sunday evening. High pressure will bring dry weather
Monday and early Tuesday. An upper low will move towards the great
lakes by the middle of next week and a cold front will move across our
region around Friday.
&&
.NEAR TERM /Tonight/...
Issued at 325 PM EDT SAT MAY 28 2016
Water vapor satellite indicated plume of moisture from Mississippi and
Alabama north across our region. Showers and thunderstorms were
beginning to develop across our region with day time heating and and
high resolution shows an increase of thunderstorms into the early
evening hour and then diminishing or ending most areas by late evening.
Will mention slight chance POPs west and chance POPS east early this evening
and then thunderstorms ending most areas by midnight. Then a weak upper
disturbance may produce a few light showers late tonight.
Lows tonight will be in the middle 60s which is close to a MOS blend.
&&
.SHORT TERM /Sunday through Tuesday/...
Issued at 325 PM EDT SAT MAY 28 2016
Models have trended drier towards Sunday and most models indicate little if
any precipitation. However with a cold front moving into our region late Sunday
prefer to keep low chance POPS in mainly Sunday afternoon and far east
Sunday evening.
After that weak high pressure will bring a period of dry weather later
Sunday night through early Tuesday. The NAM and GFS models are quicker in spreading
precip our way late Monday and Tuesday. I believe they are too quick given
that weak high pressure will be moving east across our region along with a
weak upper ridge. New European keeps this next area of precipitation farther
west and will lean in that direction. To match up with other offices will add
a slight chance of thunderstorms over northwest sections late Tuesday. Otherwise...
the rest of the short term will be dry.
Models keep 850 MB temperatures in the lower to middle teens and with more sunshine
high temperatures will be a little warmer with highs in the middle 80s. With
mostly clear skies and light winds lows will be in the lower 60s Sunday night and
lower to middle 60s Monday night. In most cases stayed close to a MOS blend on
temperatures.
&&
.LONG TERM /Tuesday Night through Saturday/...
Issued at 159 PM EDT Sat May 28 2016
ECMWF continue to keeps the warm and humid air mass in place
across central Indiana through Thursday. Thus as superblend
suggests...kept low chance pops in place during that time to
account for diurnal showers and storms.
Best chances for rain look to be on Thursday afternoon and evening
as the ECMWF shows a cold front crossing Indiana from the
northwest. With ample moisture in place ahead of the
front...precipitation seems like a good bet here.
Superblend continued to keep low chance pops in the forecast on
Friday and Saturday. The ECMWF shows the cold front southeast of
Indiana at that time...along with subsidence in place along with a
cooler and dryer air mass in place amid NW flow. Therefore we
twiddled the pop grids down 5-10% to achieve a dry forecast then.
&&
.AVIATION /Discussion for 290000z TAF issuance/...
Issued at 714 PM EDT Sat May 28 2016
A brief light shower could move over KIND over the next hour but
this shouldn`t cause any flight reductions. Later tonight could
see some MVFR fog develop at the outlying sites after around 8-9z
with ample low level moisture available and winds dropping off to
around 5 kts or less. Some cloud cover should keep things from
dropping off too much. Hi res models are showing the line of
thunderstorms currently over Illinois and stretching south into
Missouri weakening and scattering out before it gets to Indiana
and as a result will leave this out. Will again have some chances
for thunderstorms Sunday especially during the afternoon ahead of
the cold frontal passage making it more likely at KIND and KBMG.
More likely in this case though still means a 30 percent chance or
less of hitting either site so will leave out for now. Forecast
soundings show some potential for wind gusts around 14-20 kts out
of the west generally in the wake of the frontal passage.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....PUMA
AVIATION...CP
Area Forecast Discussion
National Weather Service Northern Indiana
140 PM EDT SAT MAY 28 2016
.SYNOPSIS...
Issued at 126 PM EDT Sat May 28 2016
Scattered showers and a few thunderstorms are expected in the
area this afternoon as a weak upper air disturbance moves through.
The shower activity will diminish tonight. A weak cold front will
move across the area Sunday bringing a renewed chance of showers
and thunderstorms. Fair weather is expected for Memorial Day as
high pressure builds in behind the front. Temperatures will remain
above normal with highs in the lower to middle 80s and lows in the
lower to middle 60s.
&&
.SHORT TERM...(Today and Tonight)
Issued at 401 AM EDT Sat May 28 2016
More of the same in the short term period as warm and moist airmass
remains in place with only subtle short waves providing any
mechanism for ascent. Satellite shows a subtle short wave lifting
north through central Indiana early this morning within modest theta
E axis. This has led to a few showers over central Indiana. Hires
models lift this area of pcpn north again today similar to
yesterday. Isolated showers and maybe an isolated tsra this morning
with these features. Atmosphere then becomes unstable again this
afternoon with CAPEs in the 2-3K J/kg range. Models continue to
develop afternoon convection and must once again include low chance
pops given instability and potential for weak short wave. Slightly
better moisture axis shifts eastward today and models indicating
best potential for convection to be in the east. Loss of diurnal
heating tonight will diminish most convection. Focus will shift back
west late as slightly stronger short wave and surface cold front
begin to approach. High temps today will again be in the 80s
with mid 80s possible again depending on amount of clouds.
&&
.LONG TERM...(Sunday through Friday)
Issued at 401 AM EDT Sat May 28 2016
Upper low expected to lift northeast into the western Great Lakes on
Sunday while dampening. Associated weak surface cold front will move
across the area. Weak low level convergence coupled with afternoon
CAPE values of 2-3K j/kg and 0-6km bulk shear around 30 knots could
allow for a few strong to severe storms. Timing suggest eastern
areas but models not overly aggressive with convective development.
Maintained low to mid chance pops with highest in the east during
the afternoon. Drying and subsidence then work in and should see a
nice Memorial Day with lower dew points...though a few models
bringing some additional moisture back in later Monday.
Another upper low expected to drop into northern plains next week
with a similar setup of broad moisture plume and weak forcing
ahead of it. This low looks a bit more progressive across the
northern tier of states. Stronger short wave moves through
Thursday with cooler and drier air possible by friday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 126 PM EDT Sat May 28 2016
Sct shra and a few ts expected to develop this aftn as a wk
shrtwv moves rapidly ne from the lwr/mid MS Valley across IN. A
little strong shrtwv expected to move fm w-e across the area
Sunday, but decreasing moisture in advance of the system supports
not adding shra/ts mention to tafs attm. Otrws, vfr conditions
should cont with moderately strong southerly flow grdly veering to
west on Sunday.
&&
.IWX Watches/Warnings/Advisories...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...JT
SHORT TERM...Lashley
LONG TERM...Lashley
AVIATION...JT
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Area Forecast Discussion
National Weather Service Indianapolis IN
105 PM EDT SAT MAY 28 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 330 AM EDT Sat May 28 2016
A warm and humid air mass will persist across the region through the
weekend with chances for showers and thunderstorms as a series of
upper waves pass through the Ohio Valley. Rain chances will end once
a weakening cold front passes through on Sunday...with less humid
weather for Monday and Tuesday. Scattered thunderstorms will return
to central Indiana by mid week as a storm system tracks through the
region. Cooler and drier conditions are expected by next weekend.
&&
.NEAR TERM /rest of Today/...
Issued at 940 AM EDT Sat May 28 2016
.UPDATE...Only minor tweaks made to grids mainly to raise POPS to 50
percent across the eastern half of our region where the deepest
moisture will be. High res model shows an increase in showers and
storms this afternoon as it moves north northeast across our region.
Otherwise...the remainder of the near term is on track.
Portion of previous near term discussion follows...
The Ohio Valley will remain entrenched within a moist southwest flow
aloft as a stubborn upper low over the central plains this morning
lifts northeast through the course of the day. Weak and poorly
defined perturbations aloft continue to eject out from the upper low
and lift into the area and will once again serve to offer forcing
for convective development today...especially this afternoon during
peak heating.
Deeper moisture advecting into the region courtesy of stronger low
level flow helping to generate the isolated activity early this
morning. A few lightning strikes cannot be ruled out with
mesoanalysis indicating subtle instability present...but overall
primarily anticipating showers through mid morning. Slightly
stronger wave aloft poised to lift into the Ohio Valley this
afternoon and with the airmass becoming more unstable with
heating...expect more of a convective component over the forecast
area with scattered thunderstorms developing. Primary focus for
greatest convective coverage likely to align over the eastern half
of the forecast area where axis of deeper moisture will reside...but
chance pops are warranted over all of central Indiana this
afternoon. With boundary layer shear lacking...expect convection to
remain largely disorganized later today with brief heavy downpours
as the main impact.
Temps...Expect less sunshine than Friday for most as model soundings
and RH progs showing a lot of potential for clouds through the
course of the day. This will serve to keep max temps cooler than
Friday...with low level thermals supporting highs generally in the
lower 80s.
&&
.SHORT TERM /Tonight through Monday Night/...
Issued at 330 AM EDT Sat May 28 2016
Forecast challenges focus on convective chances through Sunday
followed by drier weather for Memorial Day as weak high pressure
arrives.
The aforementioned upper low will become slowly absorbed into the
mean flow aloft on Sunday as it tracks east across the Great Lakes.
The remnant wave aloft will enhance lift across the region and
combine with a weakening cold front to provide another round for
scattered convection during the afternoon and evening Sunday. Strong
surface heating will produce a modestly unstable airmass with
steepening lapse rates as cooler and drier air in the mid levels
arrives Despite weak low level flow and boundary layer shear...the
frontal boundary and wave aloft should support potential for more
organized and stronger convection in a multicellular mode.
Thermodynamic profiles suggestive of gusty wind and hail potential
with stronger cells. Timing differences still exist between various
models...but chance pops remain warranted and focused during the
second half of the afternoon into the evening as the front tracks
across the area.
Drier air will overspread the region Sunday night as weak surface
ridging reestablishes and the weakening wave aloft departs off to
the east. A dry and slightly less humid airmass will settle into the
Ohio Valley for Memorial Day and Monday night with the surface ridge
in control over the area and slowly rising heights aloft.
Temps...Warm weather will continue across the region through the
short term. Low level thermals remain supportive of highs rising
into the mid 80s both Sunday and Monday for most areas.
&&
.LONG TERM /Tuesday Through Friday/...
Issued at 231 AM EDT Sat May 28 2016
Models are close enough that the SuperBlend initialization was
accepted for most items.
During the long term, an upper trough will move into the area. A
surface frontal system will also move through. The result will be
rain chances through most of the period.
The GFS appears to be well overdoing rain chances early in the
period given expected forcing at that time. Its influence on
SuperBlend requires cutting back on SuperBlend`s PoPs on Tuesday.
Above normal temperatures early in the period will give way to near
to slightly below normal values by Friday.
&&
.AVIATION /discussion for the 281800z tafs/...
Issued at 105 PM EDT Sat May 28 2016
VFR conditions expected much of this taf period. Brief MVFR
conditions will be possible late this afternoon and early evening
within any TSRA that may strike a TAF site.
Rapid Refresh continues to suggest convective development...mainly
during the peak heating hours of 20Z-01z. Thus have used VCTS for
now along with a TEMPO group for thunder during this most
favorable period.
Any spots that get rain...particularly the more rural taf sites
will be favorable for MVFR diurnal fog in the morning given the
expected lingering lower level moisture and small dew point
depressions.
CU rule is negative on sunday morning and low level moisture
lingers. Used VFR CIGS to cover this situation.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM...50
AVIATION...JP
Area Forecast Discussion
National Weather Service Indianapolis IN
940 AM EDT SAT MAY 28 2016
.UPDATE...
Near term for the rest of today has been updated below.
&&
.SYNOPSIS...
Issued at 330 AM EDT Sat May 28 2016
A warm and humid air mass will persist across the region through the
weekend with chances for showers and thunderstorms as a series of
upper waves pass through the Ohio Valley. Rain chances will end once
a weakening cold front passes through on Sunday...with less humid
weather for Monday and Tuesday. Scattered thunderstorms will return
to central Indiana by mid week as a storm system tracks through the
region. Cooler and drier conditions are expected by next weekend.
&&
.NEAR TERM /rest of Today/...
Issued at 940 AM EDT Sat May 28 2016
.UPDATE...Only minor tweaks made to grids mainly to raise POPS to 50
percent across the eastern half of our region where the deepest
moisture will be. High res model shows an increase in showers and
storms this afternoon as it moves north northeast across our region.
Otherwise...the remainder of the near term is on track.
Portion of previous near term discussion follows...
The Ohio Valley will remain entrenched within a moist southwest flow
aloft as a stubborn upper low over the central plains this morning
lifts northeast through the course of the day. Weak and poorly
defined perturbations aloft continue to eject out from the upper low
and lift into the area and will once again serve to offer forcing
for convective development today...especially this afternoon during
peak heating.
Deeper moisture advecting into the region courtesy of stronger low
level flow helping to generate the isolated activity early this
morning. A few lightning strikes cannot be ruled out with
mesoanalysis indicating subtle instability present...but overall
primarily anticipating showers through mid morning. Slightly
stronger wave aloft poised to lift into the Ohio Valley this
afternoon and with the airmass becoming more unstable with
heating...expect more of a convective component over the forecast
area with scattered thunderstorms developing. Primary focus for
greatest convective coverage likely to align over the eastern half
of the forecast area where axis of deeper moisture will reside...but
chance pops are warranted over all of central Indiana this
afternoon. With boundary layer shear lacking...expect convection to
remain largely disorganized later today with brief heavy downpours
as the main impact.
Temps...Expect less sunshine than Friday for most as model soundings
and RH progs showing a lot of potential for clouds through the
course of the day. This will serve to keep max temps cooler than
Friday...with low level thermals supporting highs generally in the
lower 80s.
&&
.SHORT TERM /Tonight through Monday Night/...
Issued at 330 AM EDT Sat May 28 2016
Forecast challenges focus on convective chances through Sunday
followed by drier weather for Memorial Day as weak high pressure
arrives.
The aforementioned upper low will become slowly absorbed into the
mean flow aloft on Sunday as it tracks east across the Great Lakes.
The remnant wave aloft will enhance lift across the region and
combine with a weakening cold front to provide another round for
scattered convection during the afternoon and evening Sunday. Strong
surface heating will produce a modestly unstable airmass with
steepening lapse rates as cooler and drier air in the mid levels
arrives Despite weak low level flow and boundary layer shear...the
frontal boundary and wave aloft should support potential for more
organized and stronger convection in a multicellular mode.
Thermodynamic profiles suggestive of gusty wind and hail potential
with stronger cells. Timing differences still exist between various
models...but chance pops remain warranted and focused during the
second half of the afternoon into the evening as the front tracks
across the area.
Drier air will overspread the region Sunday night as weak surface
ridging reestablishes and the weakening wave aloft departs off to
the east. A dry and slightly less humid airmass will settle into the
Ohio Valley for Memorial Day and Monday night with the surface ridge
in control over the area and slowly rising heights aloft.
Temps...Warm weather will continue across the region through the
short term. Low level thermals remain supportive of highs rising
into the mid 80s both Sunday and Monday for most areas.
&&
.LONG TERM /Tuesday Through Friday/...
Issued at 231 AM EDT Sat May 28 2016
Models are close enough that the SuperBlend initialization was
accepted for most items.
During the long term, an upper trough will move into the area. A
surface frontal system will also move through. The result will be
rain chances through most of the period.
The GFS appears to be well overdoing rain chances early in the
period given expected forcing at that time. Its influence on
SuperBlend requires cutting back on SuperBlend`s PoPs on Tuesday.
Above normal temperatures early in the period will give way to near
to slightly below normal values by Friday.
&&
.AVIATION (Discussion for the 281200Z TAF Issuance)...
Issued at 636 AM EDT Sat May 28 2016
Outside of convection, VFR conditions expected. Winds will become
gusty this afternoon.
While an isolated shower cannot be ruled out this morning, it
appears that the sites will likely remain dry with mainly mid cloud
around.
This afternoon winds will gust near 20kt. Instability will build and
scattered showers and thunderstorms will develop. At the moment
believe coverage will be enough to use a VCTS mention for a few
hours during peak heating.
Convection will then diminish and winds will decrease. &&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM...50
AVIATION...50
Area Forecast Discussion
National Weather Service Indianapolis IN
636 AM EDT SAT MAY 28 2016
.UPDATE...
The AVIATION section has been updated below.
&&
.SYNOPSIS...
Issued at 330 AM EDT Sat May 28 2016
A warm and humid airmass will persist across the region through the
weekend with chances for showers and thunderstorms as a series of
upper waves pass through the Ohio Valley. Rain chances will end once
a weakening cold front passes through on Sunday...with less humid
weather for Monday and Tuesday. Scattered thunderstorms will return
to central Indiana by mid week as a storm system tracks through the
region. Cooler and drier conditions are expected by next weekend.
&&
.NEAR TERM /Today/...
Issued at 330 AM EDT Sat May 28 2016
Moist southerly flow continues across the region early this
morning with clouds increasing. Isolated brief downpours lifting
north across southern counties on the leading edge of an area of
higher precipitable water. Warm and humid conditions persist with
07Z temps ranging from the upper 60s to the mid 70s.
The Ohio Valley will remain entrenched within a moist southwest flow
aloft as a stubborn upper low over the central plains this morning
lifts northeast through the course of the day. Weak and poorly
defined perturbations aloft continue to eject out from the upper low
and lift into the area and will once again serve to offer forcing
for convective development today...especially this afternoon during
peak heating.
Deeper moisture advecting into the region courtesy of stronger low
level flow helping to generate the isolated activity early this
morning. A few lightning strikes cannot be ruled out with
mesoanalysis indicating subtle instability present...but overall
primarily anticipating showers through mid morning. Slightly
stronger wave aloft poised to lift into the Ohio Valley this
afternoon and with the airmass becoming more unstable with
heating...expect more of a convective component over the forecast
area with scattered thunderstorms developing. Primary focus for
greatest convective coverage likely to align over the eastern half
of the forecast area where axis of deeper moisture will reside...but
chance pops are warranted over all of central Indiana this
afternoon. With boundary layer shear lacking...expect convection to
remain largely disorganized later today with brief heavy downpours
as the main impact.
Temps...Expect less sunshine than Friday for most as model soundings
and RH progs showing a lot of potential for clouds through the
course of the day. This will serve to keep max temps cooler than
Friday...with low level thermals supporting highs generally in the
lower 80s.
&&
.SHORT TERM /Tonight through Monday Night/...
Issued at 330 AM EDT Sat May 28 2016
Forecast challenges focus on convective chances through Sunday
followed by drier weather for Memorial Day as weak high pressure
arrives.
The aforementioned upper low will become slowly absorbed into the
mean flow aloft on Sunday as it tracks east across the Great Lakes.
The remnant wave aloft will enhance lift across the region and
combine with a weakening cold front to provide another round for
scattered convection during the afternoon and evening Sunday. Strong
surface heating will produce a modestly unstable airmass with
steepening lapse rates as cooler and drier air in the mid levels
arrives Despite weak low level flow and boundary layer shear...the
frontal boundary and wave aloft should support potential for more
organized and stronger convection in a multicellular mode.
Thermodynamic profiles suggestive of gusty wind and hail potential
with stronger cells. Timing differences still exist between various
models...but chance pops remain warranted and focused during the
second half of the afternoon into the evening as the front tracks
across the area.
Drier air will overspread the region Sunday night as weak surface
ridging reestablishes and the weakening wave aloft departs off to
the east. A dry and slightly less humid airmass will settle into the
Ohio Valley for Memorial Day and Monday night with the surface ridge
in control over the area and slowly rising heights aloft.
Temps...Warm weather will continue across the region through the
short term. Low level thermals remain supportive of highs rising
into the mid 80s both Sunday and Monday for most areas.
&&
.LONG TERM /Tuesday Through Friday/...
Issued at 231 AM EDT Sat May 28 2016
Models are close enough that the SuperBlend initialization was
accepted for most items.
During the long term, an upper trough will move into the area. A
surface frontal system will also move through. The result will be
rain chances through most of the period.
The GFS appears to be well overdoing rain chances early in the
period given expected forcing at that time. Its influence on
SuperBlend requires cutting back on SuperBlend`s PoPs on Tuesday.
Above normal temperatures early in the period will give way to near
to slightly below normal values by Friday.
&&
.AVIATION (Discussion for the 281200Z TAF Issuance)...
Issued at 636 AM EDT Sat May 28 2016
Outside of convection, VFR conditions expected. Winds will become
gusty this afternoon.
While an isolated shower cannot be ruled out this morning, it
appears that the sites will likely remain dry with mainly mid cloud
around.
This afternoon winds will gust near 20kt. Instability will build and
scattered showers and thunderstorms will develop. At the moment
believe coverage will be enough to use a VCTS mention for a few
hours during peak heating.
Convection will then diminish and winds will decrease. &&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...50
AVIATION...50
Area Forecast Discussion
National Weather Service Indianapolis IN
231 AM EDT SAT MAY 28 2016
.UPDATE...
The LONG TERM section has been updated below.
&&
.SYNOPSIS...
Issued at 306 PM EDT FRI MAY 27 2016
A strong upper ridge of high pressure along the U.S. east coast will
keep us in a summer like pattern until late next week. A series of
weak upper disturbances will bring chances of thunderstorms through
the weekend as they move across our region.
High pressure will bring dry weather Monday and Tuesday. An upper low
moving towards the great lakes will bring a chance of thunderstorms
again from the middle of next week on...along with slightly cooler
temperatures late next week.
&&
.NEAR TERM /Rest of Tonight/...
Issued at 957 PM EDT Fri May 27 2016
UPDATE...
Current radar mosaic shows scattered showers and thunderstorms
tracking across western portions of Central Indiana as mentioned
in previous forecast. As a result, minimal changes. Current temps
across the area are ranging from the low to upper 70s and are
still expected to only drop into the upper 60s overnight. Updated
grids have been sent.
PREVIOUS DISCUSSION...
Water vapor satellite indicated a strong upper ridge along the
east coast while an upper low was over eastern Colorado. So far it
has been pretty quiet across Indiana today...but an upper
disturbance moving into the lower Mississippi valley was producing
scattered to numerous thunderstorms over lower and middle
Mississippi valley this afternoon.
Some of these thunderstorms may spread into western and central parts of our
region by late evening as an upper disturbance moves our way. Will mention
a chance of thunderstorms from INDY and westward towards midnight and a
slight chance of storms elsewhere as an disturbance passes by.
Given that there is no change of air mass lows tonight should again
be in the lower to middle 60s which is close to a MOS blend.
&&
.SHORT TERM /Saturday through Monday/...
Issued at 306 PM EDT FRI MAY 27 2016
Forecast focus continue to be rain chances over the weekend as a couple
of weak upper disturbances move from the southern and central plains
towards the great lakes. Air mass will remain moist and unstable
over the weekend and in addition models move a weak cold front our
way Sunday. Models indicate thunderstorms will be partially diurnal
and will mention chance POPS Saturday afternoon and Sunday and
slight chance POPS most other periods through Sunday evening.
After that will go dry as drier air and weak high pressure builds
into our region late Sunday night and Monday.
There will be a bit more clouds which may limit temperatures
Saturday. But overall highs will be in the lower to middle 80s all
3 days while lows will be in the middle to upper 60s over the
weekend and lower 60s Monday morning.
&&
.LONG TERM /Tuesday Through Friday/...
Issued at 231 AM EDT SAT MAY 28 2016
Models are close enough that the SuperBlend initialization was
accepted for most items.
During the long term, an upper trough will move into the area. A
surface frontal system will also move through. The result will be
rain chances through most of the period.
The GFS appears to be well overdoing rain chances early in the
period given expected forcing at that time. Its influence on
SuperBlend requires cutting back on SuperBlend`s PoPs on Tuesday.
Above normal temperatures early in the period will give way to near
to slightly below normal values by Friday.
&&
.AVIATION /Discussion for 280600z TAF issuance/...
Issued at 1230 AM EDT Sat May 28 2016
Starting to see a few weak echoes in central Indiana and hi res
output suggest this will increase for the next few hours. Included a
VCSH for this, but with the weaker looking echoes and unimpressive
moisture in the time heights will not include any category
reductions. After around 14-16z forecast soundings show wind gusts
of 20-25 kts developing out of 180-210 and continuing through around
sunset. Could see some scattered thunderstorm development during the
afternoon as well. Confidence on timing/placement is still fairly
low, but parameters look a little better than they have the past
couple of days so will bring in a prob30 after 19z.
&&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/TDUD
SHORT TERM...JH
LONG TERM...50
AVIATION...CP
Area Forecast Discussion
National Weather Service Indianapolis IN
306 PM EDT FRI MAY 27 2016
.UPDATE...
Synopsis...near term and short term sections have been updated below.
&&
.SYNOPSIS...
Issued at 306 PM EDT FRI MAY 27 2016
A strong upper ridge of high pressure along the U.S. east coast will
keep us in a summer like pattern until late next week. A series of
weak upper disturbances will bring chances of thunderstorms through
the weekend as they move across our region.
High pressure will bring dry weather Monday and Tuesday. An upper low
moving towards the great lakes will bring a chance of thunderstorms
again from the middle of next week on...along with slightly cooler
temperatures late next week.
&&
.NEAR TERM /Tonight/...
Issued at 306 PM EDT FRI MAY 27 2016
water vapor satellite indicated a strong upper ridge along the east coast
while an upper low was over eastern Colorado. So far it has been pretty
quiet across Indiana today...but an upper disturbance moving into the
lower Mississippi valley was producing scattered to numerous thunderstorms
over lower and middle Mississippi valley this afternoon.
Some of these thunderstorms may spread into western and central parts of our
region by late evening as an upper disturbance moves our way. Will mention
a chance of thunderstorms from INDY and westward towards midnight and a
slight chance of storms elsewhere as an disturbance passes by.
Given that there is no change of air mass lows tonight should again be in the
lower to middle 60s which is close to a MOS blend.
&&
.SHORT TERM /Saturday through Monday/...
Issued at 306 PM EDT FRI MAY 27 2016
Forecast focus continue to be rain chances over the weekend as a couple
of weak upper disturbances move from the southern and central plains
towards the great lakes. Air mass will remain moist and unstable over
the weekend and in addition models move a weak cold front our way Sunday.
Models indicate thunderstorms will be partially diurnal and will mention
chance POPS Saturday afternoon and Sunday and slight chance POPS most other
periods through Sunday evening.
After that will go dry as drier air and weak high pressure builds into our region
late Sunday night and Monday.
There will be a bit more clouds which may limit temperatures Saturday. But overall
highs will be in the lower to middle 80s all 3 days while lows will be in the
middle to upper 60s over the weekend and lower 60s Monday morning.
&&
.LONG TERM /Monday Night Through Friday/...
Issued at 229 PM EDT FRI MAY 27 2016
Timing of the thunderstorms will be the main focus next week.
Ensembles suggest a cold front will move across central Indiana
Midweek followed by an upper trough late week. This should result in
more thunderstorm chances by Tuesday night after a dry start to the
week.
Temperatures will start off above normal and then slide back to
seasonable late in the week. This is reflected with the regional
blend.
&&
.AVIATION (Discussion for the 271800Z IND TAF Issuance)...
Issued at 1226 PM EDT FRI MAY 27 2016
VFR conditions expected in the TAF period with just some diurnal cu
around 4k feet below higher clouds. The exception could be at mainly
LAF and HUF...where a few thunderstorms are possible this afternoon
and evening. With confidence in coverage of any pop ups...only went
with VCTS through 06z at LAF and HUF an no mention at IND and BMG.
Will take a last minute look...however in case any adjustments need
to be made.
Winds will be south near 10 knots this afternoon and a few knots
lighter tonight.
&&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...MK
AVIATION...MK
Area Forecast Discussion
National Weather Service Indianapolis IN
229 PM EDT FRI MAY 27 2016
.UPDATE...
The Long Term section has been updated below.
&&
.SYNOPSIS...
Issued at 342 AM EDT Fri May 27 2016
Summer conditions will persist across central Indiana through the
holiday weekend and into next week with highs mainly in the 80s and
a humid airmass. Daily chances for storms will exist through the
weekend as weak upper level waves track through the Ohio Valley.
After a period with drier conditions for Monday and Tuesday...
chances for storms will return by midweek as a storms system tracks
through the Upper Midwest.
&&
.NEAR TERM /Rest of Today/...
Issued at 943 AM EDT Fri May 27 2016
.UPDATE...Only minor tweaks made to previous grids. Area of showers and
thunderstorms over southern Illinois should move north northeast and possibly
brushing the far northwest part of our region later today. Otherwise...
only expect isolated thunderstorms. Lowered POPS slightly some areas.
But overall previous forecast is on track.
Portion of previous near term discussion follows...
Warm front moving north through the region combining with weak mid
level perturbations in the southwest flow will serve as primary
catalysts in potential for isolated to scattered convection
developing in the moist and unstable airmass. Lack of more
substantial forcing aloft and presence of a mid level cap will be
limiting factors in convective coverage...with model soundings and
RH progs both hinting at mid level drying advecting north into the
region by this afternoon.
Primary focus for scattered storms setting up over western counties
in closer proximity to deeper moisture plume and the enhanced 850mb
flow aligning across the lower Mississippi and Ohio Valleys. Will
carry highest pops here this morning as the warm front lifts north
and again this afternoon as scattered convection develops in the
unstable airmass. Further east...the limiting factors mentioned
above support only low chance pops with any convection remaining
isolated.
Temps...Despite the convective cloud debris slowing warming early in
the day...should see some sun through the course of the day with
warmer METMOS guidance being supported by low level thermals. Expect
a muggy day with highs rising into the 80s.
&&
.SHORT TERM /Tonight through Sunday Night/...
Issued at 342 AM EDT Fri May 27 2016
Forecast challenges focus on continued convective chances throughout
much of the period as waves aloft interact with a moist and unstable
airmass across central Indiana.
Upper low centered over the High Plains will wobble northeast into
the Upper Midwest and then into western Ontario by late weekend.
Dirty southwest flow pattern aloft as multiple weak waves will
continue to eject out from the upper low and lift northeast across
the Ohio Valley and lower Great Lakes. As these waves interact with
the unstable air across the region...opportunities will exist for
isolated to scattered convection through Sunday.
As is often the case in these setups...models having all sorts
of difficulty timing the individual waves aloft creating a low
confidence forecast in timing convective impacts for the forecast
area. At this point...best chances for storms appear for Saturday
and Sunday afternoons during peak heating. Bulk of the stronger
forcing aloft remains to the west of the forecast area on
Saturday...but presence of deeper moisture and surge of slightly
better mid level lapse rates supports chance pops across the
forecast area.
Strongest wave aloft impacts the region on Sunday as a more
pronounced upper trough swings through the lower Great Lakes with a
weakening cold front tracking east. Cooler and drier air in the mid
levels associated with the upper wave will support steepening lapse
rates over the area which should present a better and slightly more
organized convective potential during the afternoon and early
evening in vicinity of the cold front. With that being said...
weaker low level flow will limit coverage to storms. Still plenty of
details to work out but higher chance pops certainly appear
warranted for the afternoon and evening Sunday. Drier air will
overspread the region Sunday night as weak high pressure builds in.
Temps...Low level thermals generally supported MOS guidance for
highs Saturday and Sunday. More clouds should keep temps down
slightly on Saturday with Sunday being the warmer day ahead of the
weak cold front. Overall...expect a muggy summer-like holiday
weekend with highs mainly in the 80s and lows in the 60s.
&&
.LONG TERM /Monday Night Through Friday/...
Issued at 229 PM EDT FRI MAY 27 2016
Timing of the thunderstorms will be the main focus next week.
Ensembles suggest a cold front will move across central Indiana
Midweek followed by an upper trough late week. This should result in
more thunderstorm chances by Tuesday night after a dry start to the
week.
Temperatures will start off above normal and then slide back to
seasonable late in the week. This is reflected with the regional
blend.
&&
.AVIATION (Discussion for the 271800Z IND TAF Issuance)...
Issued at 1226 PM EDT FRI MAY 27 2016
VFR conditions expected in the TAF period with just some diurnal cu
around 4k feet below higher clouds. The exception could be at mainly
LAF and HUF...where a few thunderstorms are possible this afternoon
and evening. With confidence in coverage of any pop ups...only went
with VCTS through 06z at LAF and HUF an no mention at IND and BMG.
Will take a last minute look...however in case any adjustments need
to be made.
Winds will be south near 10 knots this afternoon and a few knots
lighter tonight.
&&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM...MK
AVIATION...MK
Area Forecast Discussion
National Weather Service Northern Indiana
105 PM EDT FRI MAY 27 2016
.SYNOPSIS...
Issued at 403 AM EDT Fri May 27 2016
High pressure will remain nearly stationary over the southeastern
U.S. causing warm moist conditions across our area through the
Memorial Day weekend. Temperatures will remain well above normal
with highs in the lower or middle 80s and lows in the 60s. A low
chance of mainly afternoon through early evening thunderstorms
will continue into early next week.
&&
.SHORT TERM...(Today and Tonight)
Issued at 403 AM EDT Fri May 27 2016
Deep southerly flow to continue over the region today with abundant
moisture but a lack of strong forcing for ascent. Water vapor and IR
imagery showing numerous weak MCVs embedded within widespread
convection and debris cloudiness across the Midwest. Spectral models
continue to struggle with convective details given more coarse
resolution and convective models remain overdone at times. Weak flow
and lack of strong short wave makes for difficult forecast with
respect to when and where thunderstorms will develop.
Regional radar mosaic showing area of showers moving northeast from
southern IL and IN at 08z. HRRR has a decent handle on this area and
brings it into far southwest around 12z with decaying/weakening
trends as it lifts north. Have middle range chance pops for this
area. Instability again shown by models to be in the 1500-2500 j/kg
range this afternoon. concern that debris cloudiness may be more
extensive today and may not see as much afternoon sun as on
Thursday. Continued with a low to mid chance pop this afternoon with
convective models again showing some development. Highs today should
still reach lower 80s with muggy conditions as sfc dewpoints remain
in the mid 60s. Lingering low chance pops tonight in the west with
deep moisture feed and any weak MCV could easily set off a few
storms. Lows will remain in the 60s.
&&
.LONG TERM...(Saturday through Thursday)
Issued at 403 AM EDT Fri May 27 2016
Thunderstorm chances continue Saturday and Sunday as deep southwest
flow continues to pump moisture into the region. A few weak short
waves Saturday but stronger wave appears in the models for Sunday as
upper low lifts through the western Great Lakes and stronger short
wave lifts northeast over our area. 0-6km shear increases and
potential CAPES of 2k j/kg or greater if we partially clear. Will
see how this plays out as models have yet to impress in this regime.
Brief period of drying and subsidence appears likely for Memorial
Day behind departing short wave and building heights. This in part
to blocky pattern with tropical/subtropical low meandering over the
Carolinas as downstream ridging develops. Thunderstorm chances
return mid week as moisture plume returns in southwest flow as
another low moves across the northern CONUS.
Highs generally in the lower 80s during the period with lows in the
60s. Temps will trend a few degrees cooler by mid to end of week
with dew points also back into the 50s making it a bit more
comfortable.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 105 PM EDT Fri May 27 2016
Band of light showers resulting from weak disturbance lifting
northward through the area continues to weaken and is now north of
both TAF sites. Another wave moving up through central Illinois this
afternoon may have showers redeveloping in the KSBN vicinity so
will include a 3 hour window of VCSH to account for this. Otherwise
VFR through the period on south/southwest winds generally 10kts
or less.
&&
.IWX Watches/Warnings/Advisories...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Lashley
SHORT TERM...Lashley
LONG TERM...Lashley
AVIATION...Logsdon
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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
[top]
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 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
[top]
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
628 AM CDT SUN MAY 29 2016
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Isolated thunderstorms may expand in coverage some this
morning...primarily impacting KMLC and possibly KTUL/KRVS.
Brief MVFR cigs/vsbys likely in and near storms.
&&
.PREV DISCUSSION... /ISSUED 416 AM CDT SUN MAY 29 2016/
DISCUSSION...
Convective complex moving across north central Texas will limit
warm advection/moisture return into eastern OK this morning. Most
of the operations models have had a poor handle on these storms,
though the HRRR in last couple of runs has finally acknowledged
their presence and, as such, has given up on the idea of a
developing complex in western Kansas that would impact parts of
the area later today. A few elevated cells trying to develop on
north flank and may see this move into southeast OK early this
morning. Probability of additional storms this afternoon will be
dependent on the eventual fate of north Texas complex, which most
guidance tends to weaken later this morning, but this is far from
a given at this point. Overall, the highest chance still appears
to be over the western half of the forecast area through tonight.
Additional weak and subtle forcing for convection remains in
play through Monday before an upper trough swings through the
northern plains and a more substantial jet streak lifts out of
Mexico into the southern plains by Tuesday into Wednesday. This
period will offer the highest chance of precip with the attendant
threat of heavy rainfall in some areas. Frontal boundary will
bring a drier and cooler airmass to the area by Thursday with
precip chances ending and below normal temperatures to end the
week.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 86 66 84 66 / 30 30 40 30
FSM 88 67 85 67 / 30 20 40 30
MLC 85 66 84 67 / 40 30 40 30
BVO 85 63 83 64 / 30 30 40 30
FYV 84 62 82 63 / 20 20 40 30
BYV 85 62 83 62 / 20 20 40 30
MKO 84 65 83 66 / 40 30 40 30
MIO 84 63 85 65 / 20 20 40 30
F10 83 65 83 66 / 50 30 40 30
HHW 86 68 86 67 / 30 20 40 30
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...18
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
1241 PM CDT SUN MAY 29 2016
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 313 AM CDT SUN MAY 29 2016
08Z profiler data shows relatively modest mid level flow over
the central plains as water vapor imagery shows a quasi-zonal
flow over the state. Slow moving upper level low pressure systems
were noted over MN and southern CA and a closed low was seen over
British Columbia. At the surface, low pressure was weakening over
the upper Midwest while another area of low pressure formed near the
TX big bend.
For today the forecast is going to depend on mesoscale features as
models show modest mid and upper flow persisting over the forecast
area. Profiler data from KICT and KTLX show low level winds becoming
more southerly allowing from moisture over the southern plains to
begin moving back into southwestern KS. Models prog some isentropic
upglide over southwest KS and satellite shows an area of AC where
the models have the upglide. This area could end up being where
convection initiates this morning, setting the course for the rest
of the day. The NAM seems to favor this idea with a possible MCV
drifting east along the KS/OK boarder. However the GFS and HRRR cast
some doubt on this idea. In any case, there does not appear to be an
obvious boundary for low level convergence to force a parcel up and
a lack of a well defined shortwave makes it difficult to highlight
one area over another for precip chances today. If storms are to
form over southwestern KS this morning, the resulting outflow could
provide the low level focus for additional development later in the
day. In general the forecast favors precip chances more across the
southern half of the forecast area since mid level flow is nearly
zonal and the low level moisture advection appears to be south of
the area. Model progs show reasonable instability developing through
the day so there is a conditional chance for precip. I just don`t
have much confidence in what that conditions may end up being. 0-6km
shear is expected to remain rather weak through the day so chances
for organized convection appear low. So there may just be pop up
storms to deal with during the heating of the day. With this in
mind, have kept POPs in the 20 to 30 percent range today. With
decent insolation today, highs are expected to warm into the lower
80s as forecast soundings mix the boundary layer above 850MB.
For tonight, generally only carry a slight chance for precip
expecting the boundary layer to begin stabilizing with the loss of
heating and again no obvious wave within the flow. The low level jet
is progged to set up over the western half of the state with speeds
generally between 30 and 40 KTS. So there isn`t much of a warm air
advection signal for elevated storms tonight either. Lows are
expected to remain in the lower and mid 60s as southerly low level
flow prevails overnight.
.LONG TERM...(Monday through Saturday)
Issued at 313 AM CDT SUN MAY 29 2016
Sfc lee trough develops over western KS in response to the incoming
shortwave trough from the northwest on Monday afternoon. Given the
warm and moist airmass in place, latest guidance is showing
difficulty in locating the exact source of forcing and appears to be
overdoing qpf amounts, especially the ECMWF. Forecast sides closer
to the GFS and NAM solutions which develops scattered showers and
storms during the late afternoon. Confidence in precip increases
overnight Monday as the wave nears, developing an mcs over central
NE, tracking through the area through Tuesday. Likely pops were
placed here with PWAT values over an inch at times. Assuming lower
flash flood guidance values which is dependent on whether we see
rainfall Sunday or Monday, localized flooding could once again
occur.
Models clear out the trough Wednesday evening with cooler and drier
northwest flow in its wake. Clear skies and light northerly winds
drops temps below average values in the lower 70s for highs and lows
in the 50s through Friday. Upper ridge continues to dominate the
Inter Mountain west through the weekend as the CWA resides on the
eastern edge. Shortwave troughs traversing the eastern edge may
bring chances for thunderstorms Saturday evening into Sunday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1239 PM CDT SUN MAY 29 2016
Expect VFR conditions for the next 24 hours. The isolated
thunderstorms should remain west and south of the terminals.
Terminal MHK may see an isolated shower or thunderstorm late this
afternoon and early evening.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Prieto
AVIATION...Gargan