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000
FXUS63 KTOP 022340
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
640 PM CDT Tue Sep 2 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Wednesday)
Issued at 320 PM CDT TUE SEP 2 2014

Fairly zonal mid-level flow was in place across much of the
northern and central U.S. today, oriented from northwest to
southeast. At the surface, high pressure was in place across much
of the forecast area with low pressure centered over southern New
Mexico and western Texas. As of 19z, surface observations showed
the boundary that had tracked south of the forecast area yesterday
had lifted northward into the area again as a warm front,
stretching roughly from Council Grove toward Topeka. Visible
satellite imagery showed scattered low- level clouds from this
morning continuing to linger along and south of this boundary
across east central Kansas, limiting the diurnal heating and
keeping temperatures generally in the upper 70s to mid 80s.

Main focus for tonight into Wednesday is on the potential for
isolated to scattered thunderstorms to develop. The frontal boundary
may sink a bit further south again this evening before lifting once
again northward as a warm front later tonight through the overnight
hours. Models also show a couple of weak embedded shortwaves within
the mid-level flow that should lift northward toward the region.
The combination of these shortwaves and the warm front along with
support from an increasing low-level jet veering from south to
southwest overnight should help to spawn the development of
scattered convection. Soundings suggest that these storms should be
elevated, with a modest amount of instability aloft for these storms
to tap into (upwards of 1500-2500J/kg of MUCAPE). Shear values may
be a bit weaker than originally projected, with approximately
25-35kts of 0-6km bulk shear. While widespread severe weather is not
anticipated, cannot rule out some marginally severe hail and even
some gusty winds. The best chance for this hail looks to be focused
across portions of central and east central Kansas, where the better
instability is expected to be located. Short-range models have been
slowing the timing of the initial development of this scattered
activity, with a few isolated storms possible this evening and
better chances for scattered storms during the overnight hours into
Wednesday morning. These storms should quickly exit from west to
east through mid morning with clearing skies by the afternoon. A
30kt low-level jet should persist through much of the day Wednesday
with breezy southwesterly surface winds gusting upwards of 25-35mph,
helping to advect warmer temperatures and higher dewpoints into the
region. As long as the mid-level clouds sufficiently clear out
during the day, temperatures should warm into the low/mid 90s with
dewpoints reaching into the low 70s. As a result, expect afternoon
heat indices to rise into the 98 to 103 degree range.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 320 PM CDT TUE SEP 2 2014

Wednesday night and the first part of Thursday should be quiet
before a frontal boundary begins moving into the forecast area.
This frontal system is expected to linger over the area for a
couple days as the mean westerlies remain mainly north of the
forecast area. Therefore there is no real big push from the north
to the frontal boundary. However the ECMWF continues to trend a
little more progressive with the front. For now have continued the
better chances for precip from Thursday night through Friday night
and adjusted POPs down a little for Saturday because of the ECMWF
trend. Chances for severe weather will be conditional on whether
storms are able to develop ahead of the boundary within the more
unstable airmass. Since there is not much forcing, models show
much of the QPF occurring post frontal once the lift from the
front moves through. Additionally the deep layer shear within the
warm sector is rather modest with only 15 to 20 KTS of 0-6km
shear. So if storms were to develop ahead of the front, they may
tend to be more pulse type or multicellular in nature. Think highs
Thursday will be quite warm ahead of the front due to 850MB temps
around 24C and good mixing of the boundary layer. With much of
the guidance showing the front moving into north central KS late
in the day, have kept highs in the lower 90s there with mid 90s
possible elsewhere. The ECMWF and GFS suggest there should be some
decent cold air advection by Friday. With clouds and potential
rainfall expected, have trended temps cooler with highs ranging
from the lower 70s north to the mid 80s over east central KS.

Precip should come to an end by Saturday as ridging continues to
build into the area with no obvious shortwave progged by the
models. This is expected to lead to a cool and generally dry
weekend. Lows are forecast to be in the 50s and highs in the 70s
with the center of the ridge over the forecast area.

Chances for precip return to the forecast for the beginning of the
work week. Models indicate a southwesterly mid level flow
developing as heights fall across the western U.S. However
confidence in precip chances is lower than normal due to the
models generating precip based on possible mesoscale waves within
the flow. These features tend to be more transient from model run
to run. With this in mind have remained a little conservative with
POPs for Monday and Tuesday and keep chances between 20 and 40
percent. Temps should begin trending warmer for the work week as
well with southerly return flow developing. Although 850MB temps
show only modest warming so highs are forecast to be in the 80s
with lows in the 60s.

&&

.AVIATION...(For the 00Z TAFs through 00Z Wednesday Evening)
Issued at 632 PM CDT TUE SEP 2 2014

The latest models are in good agreement that scattered elevated
showers and thunderstorms are forecast to lift across the area
overnight. Not certain what the coverage will be therefore did not
add a new group to the taf. There may be a period of vis/cig
restrictions during and shortly after the storms, which may need
to be added at the next issuance.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Wolters
AVIATION...Sanders







000
FXUS63 KTOP 022020
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
320 PM CDT Tue Sep 2 2014

.SHORT TERM...(This Evening through Wednesday)
Issued at 320 PM CDT TUE SEP 2 2014

Fairly zonal mid-level flow was in place across much of the
northern and central U.S. today, oriented from northwest to
southeast. At the surface, high pressure was in place across much
of the forecast area with low pressure centered over southern New
Mexico and western Texas. As of 19z, surface observations showed
the boundary that had tracked south of the forecast area yesterday
had lifted northward into the area again as a warm front,
stretching roughly from Council Grove toward Topeka. Visible
satellite imagery showed scattered low- level clouds from this
morning continuing to linger along and south of this boundary
across east central Kansas, limiting the diurnal heating and
keeping temperatures generally in the upper 70s to mid 80s.

Main focus for tonight into Wednesday is on the potential for
isolated to scattered thunderstorms to develop. The frontal boundary
may sink a bit further south again this evening before lifting once
again northward as a warm front later tonight through the overnight
hours. Models also show a couple of weak embedded shortwaves within
the mid-level flow that should lift northward toward the region.
The combination of these shortwaves and the warm front along with
support from an increasing low-level jet veering from south to
southwest overnight should help to spawn the development of
scattered convection. Soundings suggest that these storms should be
elevated, with a modest amount of instability aloft for these storms
to tap into (upwards of 1500-2500J/kg of MUCAPE). Shear values may
be a bit weaker than originally projected, with approximately
25-35kts of 0-6km bulk shear. While widespread severe weather is not
anticipated, cannot rule out some marginally severe hail and even
some gusty winds. The best chance for this hail looks to be focused
across portions of central and east central Kansas, where the better
instability is expected to be located. Short-range models have been
slowing the timing of the initial development of this scattered
activity, with a few isolated storms possible this evening and
better chances for scattered storms during the overnight hours into
Wednesday morning. These storms should quickly exit from west to
east through mid morning with clearing skies by the afternoon. A
30kt low-level jet should persist through much of the day Wednesday
with breezy southwesterly surface winds gusting upwards of 25-35mph,
helping to advect warmer temperatures and higher dewpoints into the
region. As long as the mid-level clouds sufficiently clear out
during the day, temperatures should warm into the low/mid 90s with
dewpoints reaching into the low 70s. As a result, expect afternoon
heat indices to rise into the 98 to 103 degree range.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 320 PM CDT TUE SEP 2 2014

Wednesday night and the first part of Thursday should be quiet
before a frontal boundary begins moving into the forecast area.
This frontal system is expected to linger over the area for a
couple days as the mean westerlies remain mainly north of the
forecast area. Therefore there is no real big push from the north
to the frontal boundary. However the ECMWF continues to trend a
little more progressive with the front. For now have continued the
better chances for precip from Thursday night through Friday night
and adjusted POPs down a little for Saturday because of the ECMWF
trend. Chances for severe weather will be conditional on whether
storms are able to develop ahead of the boundary within the more
unstable airmass. Since there is not much forcing, models show
much of the QPF occurring post frontal once the lift from the
front moves through. Additionally the deep layer shear within the
warm sector is rather modest with only 15 to 20 KTS of 0-6km
shear. So if storms were to develop ahead of the front, they may
tend to be more pulse type or multicellular in nature. Think highs
Thursday will be quite warm ahead of the front due to 850MB temps
around 24C and good mixing of the boundary layer. With much of
the guidance showing the front moving into north central KS late
in the day, have kept highs in the lower 90s there with mid 90s
possible elsewhere. The ECMWF and GFS suggest there should be some
decent cold air advection by Friday. With clouds and potential
rainfall expected, have trended temps cooler with highs ranging
from the lower 70s north to the mid 80s over east central KS.

Precip should come to an end by Saturday as ridging continues to
build into the area with no obvious shortwave progged by the
models. This is expected to lead to a cool and generally dry
weekend. Lows are forecast to be in the 50s and highs in the 70s
with the center of the ridge over the forecast area.

Chances for precip return to the forecast for the beginning of the
work week. Models indicate a southwesterly mid level flow
developing as heights fall across the western U.S. However
confidence in precip chances is lower than normal due to the
models generating precip based on possible mesoscale waves within
the flow. These features tend to be more transient from model run
to run. With this in mind have remained a little conservative with
POPs for Monday and Tuesday and keep chances between 20 and 40
percent. Temps should begin trending warmer for the work week as
well with southerly return flow developing. Although 850MB temps
show only modest warming so highs are forecast to be in the 80s
with lows in the 60s.

&&

.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1219 PM CDT TUE SEP 2 2014

For the 18z TAFs, the IFR/MVFR stratus from this morning is
gradually scattering out and will push further south of the
KTOP/KFOE early this afternoon. Winds will remain light and variable
into this evening as surface high pressure shifts over the region.
There is the potential for scattered thunderstorms to develop near
the TAF sites overnight into Wednesday morning as a warm front lifts
northward into the region. Have just a mention of VCTS at this time
due to uncertainty still in the timing and location of this
activity. Some models are suggesting that VIS may be reduced to
MVFR/IFR conditions at times with these scattered thunderstorms. Did
not include with this TAF issuance, but will continue to monitor
this potential in future updates.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Hennecke
LONG TERM...Wolters
AVIATION...Hennecke








000
FXUS63 KTOP 022020
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
320 PM CDT Tue Sep 2 2014

.SHORT TERM...(This Evening through Wednesday)
Issued at 320 PM CDT TUE SEP 2 2014

Fairly zonal mid-level flow was in place across much of the
northern and central U.S. today, oriented from northwest to
southeast. At the surface, high pressure was in place across much
of the forecast area with low pressure centered over southern New
Mexico and western Texas. As of 19z, surface observations showed
the boundary that had tracked south of the forecast area yesterday
had lifted northward into the area again as a warm front,
stretching roughly from Council Grove toward Topeka. Visible
satellite imagery showed scattered low- level clouds from this
morning continuing to linger along and south of this boundary
across east central Kansas, limiting the diurnal heating and
keeping temperatures generally in the upper 70s to mid 80s.

Main focus for tonight into Wednesday is on the potential for
isolated to scattered thunderstorms to develop. The frontal boundary
may sink a bit further south again this evening before lifting once
again northward as a warm front later tonight through the overnight
hours. Models also show a couple of weak embedded shortwaves within
the mid-level flow that should lift northward toward the region.
The combination of these shortwaves and the warm front along with
support from an increasing low-level jet veering from south to
southwest overnight should help to spawn the development of
scattered convection. Soundings suggest that these storms should be
elevated, with a modest amount of instability aloft for these storms
to tap into (upwards of 1500-2500J/kg of MUCAPE). Shear values may
be a bit weaker than originally projected, with approximately
25-35kts of 0-6km bulk shear. While widespread severe weather is not
anticipated, cannot rule out some marginally severe hail and even
some gusty winds. The best chance for this hail looks to be focused
across portions of central and east central Kansas, where the better
instability is expected to be located. Short-range models have been
slowing the timing of the initial development of this scattered
activity, with a few isolated storms possible this evening and
better chances for scattered storms during the overnight hours into
Wednesday morning. These storms should quickly exit from west to
east through mid morning with clearing skies by the afternoon. A
30kt low-level jet should persist through much of the day Wednesday
with breezy southwesterly surface winds gusting upwards of 25-35mph,
helping to advect warmer temperatures and higher dewpoints into the
region. As long as the mid-level clouds sufficiently clear out
during the day, temperatures should warm into the low/mid 90s with
dewpoints reaching into the low 70s. As a result, expect afternoon
heat indices to rise into the 98 to 103 degree range.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 320 PM CDT TUE SEP 2 2014

Wednesday night and the first part of Thursday should be quiet
before a frontal boundary begins moving into the forecast area.
This frontal system is expected to linger over the area for a
couple days as the mean westerlies remain mainly north of the
forecast area. Therefore there is no real big push from the north
to the frontal boundary. However the ECMWF continues to trend a
little more progressive with the front. For now have continued the
better chances for precip from Thursday night through Friday night
and adjusted POPs down a little for Saturday because of the ECMWF
trend. Chances for severe weather will be conditional on whether
storms are able to develop ahead of the boundary within the more
unstable airmass. Since there is not much forcing, models show
much of the QPF occurring post frontal once the lift from the
front moves through. Additionally the deep layer shear within the
warm sector is rather modest with only 15 to 20 KTS of 0-6km
shear. So if storms were to develop ahead of the front, they may
tend to be more pulse type or multicellular in nature. Think highs
Thursday will be quite warm ahead of the front due to 850MB temps
around 24C and good mixing of the boundary layer. With much of
the guidance showing the front moving into north central KS late
in the day, have kept highs in the lower 90s there with mid 90s
possible elsewhere. The ECMWF and GFS suggest there should be some
decent cold air advection by Friday. With clouds and potential
rainfall expected, have trended temps cooler with highs ranging
from the lower 70s north to the mid 80s over east central KS.

Precip should come to an end by Saturday as ridging continues to
build into the area with no obvious shortwave progged by the
models. This is expected to lead to a cool and generally dry
weekend. Lows are forecast to be in the 50s and highs in the 70s
with the center of the ridge over the forecast area.

Chances for precip return to the forecast for the beginning of the
work week. Models indicate a southwesterly mid level flow
developing as heights fall across the western U.S. However
confidence in precip chances is lower than normal due to the
models generating precip based on possible mesoscale waves within
the flow. These features tend to be more transient from model run
to run. With this in mind have remained a little conservative with
POPs for Monday and Tuesday and keep chances between 20 and 40
percent. Temps should begin trending warmer for the work week as
well with southerly return flow developing. Although 850MB temps
show only modest warming so highs are forecast to be in the 80s
with lows in the 60s.

&&

.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1219 PM CDT TUE SEP 2 2014

For the 18z TAFs, the IFR/MVFR stratus from this morning is
gradually scattering out and will push further south of the
KTOP/KFOE early this afternoon. Winds will remain light and variable
into this evening as surface high pressure shifts over the region.
There is the potential for scattered thunderstorms to develop near
the TAF sites overnight into Wednesday morning as a warm front lifts
northward into the region. Have just a mention of VCTS at this time
due to uncertainty still in the timing and location of this
activity. Some models are suggesting that VIS may be reduced to
MVFR/IFR conditions at times with these scattered thunderstorms. Did
not include with this TAF issuance, but will continue to monitor
this potential in future updates.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Hennecke
LONG TERM...Wolters
AVIATION...Hennecke







000
FXUS63 KTOP 021720
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1220 PM CDT Tue Sep 2 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 312 AM CDT TUE SEP 2 2014

Analysis at 08Z depicts the upper trough axis rotating through Iowa
and Minnesota. Meanwhile the stationary front was positioned from
southwest to northeast over eastern KS. Scattered thunderstorms have
been ongoing for the past several hours as a result of this
boundary. Convection is expected to track south and east away from
the CWA this morning. Clearing skies along and north of the boundary
where dewpoints reside in the upper 60s and low 70s may develop
patchy fog through sunrise. Scattered mid level clouds and surface
winds remaining slightly mixed in some locations should prohibit
widespread development. Areas south of Interstate 70 see the best
chance for patchy fog to form and lift shortly after sunrise.

Light winds and mostly sunny skies reside for much of the afternoon
with highs in the middle to upper 80s. Focus turns to thunderstorm
chances beginning late this afternoon as the aforementioned
stationary front lifts northward as a warm front through east central
KS. Moisture pools along and north of the boundary with dewpoints
progged near 70 degrees. MLCAPE gradient tightens after 21Z with
latest guidance averaging near 3000 J/KG. Main question for this
afternoon is the strength of the capping inversion. Contrary to the
guidance consensus, the past runs of the NAM show a much weaker cap
near the boundary, initiating thunderstorms mainly along and south
of I 70 between 21Z and 03Z. Confidence is marginal on storms
developing during the late afternoon with increased chances this
evening as the veering LLJ transports deeper moisture into the area.
The stronger updrafts will be capable of large hail and isolated
strong wind gusts through early evening. Expect activity to weaken
as it tracks towards western Missouri by Wednesday morning. Cloud
cover within the warm sector tonight should limit lows to the upper
60s.

.LONG TERM...(Wednesday through Monday)
Issued at 312 AM CDT TUE SEP 2 2014

Forecast highlights in the long term include hot temperatures and
heat index on Wednesday and perhaps into Thursday, timing of a
front and associated precipitation chances late Thursday into the
weekend, and a significant cool down behind the front.

Any remnant thunderstorms should be quick to move east of the area
on Wednesday morning. Warm advection through the night and into
the day on Wednesday, along with deep boundary layer mixing,
ample sunshine, and gusty south winds all point to a hot day on
Wednesday. Temperatures are likely to rise well into the 90s, and
while the mixing will be deep the airmass above the mixed layer
will be quite moist and dewpoints may remain in the upper 60s to
lower 70s through the day. This will result in the heat index
ranging from 100 to 105 with some potential to climb into the
105-110 range depending on the eventual dewpoints. A building cap
through the day will prevent any thunderstorm activity through
Thursday morning. Thursday morning lows will be very warm in the
70s, setting the stage for another hot day. A cold front will
approach the area from the northwest by late in the day on
Thursday as a strong trough moves through North Dakota. Current
model timing suggests the front will enter the forecast area by
mid afternoon on Thursday with a thermal ridge immediately in
advance of the front and another well-mixed boundary layer.
Thursday should at least have somewhat drier air available to mix
down to the surface so while temperatures may be a bit warmer, the
dewpoints should be a bit lower. The end result will be a heat
index in the 98-105 range although it seems that Thursday has some
potential to be hotter than the current forecast depending on
frontal timing.

The strongest instability and forcing is expected to be northeast
of the area over Iowa where dewpoints will be higher on Thursday,
but convergence along the front should be sufficient for at least
a chance of thunderstorms by late afternoon into the evening in
northern Kansas. Wind shear will be very weak but with the hot
conditions could see a localized damaging wind threat materialize.
As the low level jet intensifies a bit through the evening, may
see increased thunderstorm coverage despite the LLJ being largely
parallel to the front. Some model guidance is quite aggressive in
producing widespread precip, but with the parallel LLJ and a lack
of strong forcing aloft have trended POPs a bit lower through
Friday morning...although still a fair chance. The front will hang
up over central/southern KS on Friday with faster westerly flow
moving overhead along with embedded weak short wave troughs. This
points to periodic chances for thunderstorms into Friday night,
with chances decreasing during the day on Saturday as the front
continues to push farther south. Then have a dry forecast for
Saturday night into Sunday before troughing builds into the
western CONUS and return flow brings a moisture surge back north
with renewed thunderstorm chances for Monday. Post-frontal
temperatures Friday through Sunday will be much cooler, with highs
likely only in the 70s and lows into the 50s. The main uncertainty
in eventual temperatures will be the density of cloud cover, but
can say with confidence that it will be well below normal this
weekend.

&&

.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1219 PM CDT TUE SEP 2 2014

For the 18z TAFs, the IFR/MVFR stratus from this morning is
gradually scattering out and will push further south of the
KTOP/KFOE early this afternoon. Winds will remain light and variable
into this evening as surface high pressure shifts over the region.
There is the potential for scattered thunderstorms to develop near
the TAF sites overnight into Wednesday morning as a warm front lifts
northward into the region. Have just a mention of VCTS at this time
due to uncertainty still in the timing and location of this
activity. Some models are suggesting that VIS may be reduced to
MVFR/IFR conditions at times with these scattered thunderstorms. Did
not include with this TAF issuance, but will continue to monitor
this potential in future updates.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Hennecke








000
FXUS63 KTOP 021720
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1220 PM CDT Tue Sep 2 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 312 AM CDT TUE SEP 2 2014

Analysis at 08Z depicts the upper trough axis rotating through Iowa
and Minnesota. Meanwhile the stationary front was positioned from
southwest to northeast over eastern KS. Scattered thunderstorms have
been ongoing for the past several hours as a result of this
boundary. Convection is expected to track south and east away from
the CWA this morning. Clearing skies along and north of the boundary
where dewpoints reside in the upper 60s and low 70s may develop
patchy fog through sunrise. Scattered mid level clouds and surface
winds remaining slightly mixed in some locations should prohibit
widespread development. Areas south of Interstate 70 see the best
chance for patchy fog to form and lift shortly after sunrise.

Light winds and mostly sunny skies reside for much of the afternoon
with highs in the middle to upper 80s. Focus turns to thunderstorm
chances beginning late this afternoon as the aforementioned
stationary front lifts northward as a warm front through east central
KS. Moisture pools along and north of the boundary with dewpoints
progged near 70 degrees. MLCAPE gradient tightens after 21Z with
latest guidance averaging near 3000 J/KG. Main question for this
afternoon is the strength of the capping inversion. Contrary to the
guidance consensus, the past runs of the NAM show a much weaker cap
near the boundary, initiating thunderstorms mainly along and south
of I 70 between 21Z and 03Z. Confidence is marginal on storms
developing during the late afternoon with increased chances this
evening as the veering LLJ transports deeper moisture into the area.
The stronger updrafts will be capable of large hail and isolated
strong wind gusts through early evening. Expect activity to weaken
as it tracks towards western Missouri by Wednesday morning. Cloud
cover within the warm sector tonight should limit lows to the upper
60s.

.LONG TERM...(Wednesday through Monday)
Issued at 312 AM CDT TUE SEP 2 2014

Forecast highlights in the long term include hot temperatures and
heat index on Wednesday and perhaps into Thursday, timing of a
front and associated precipitation chances late Thursday into the
weekend, and a significant cool down behind the front.

Any remnant thunderstorms should be quick to move east of the area
on Wednesday morning. Warm advection through the night and into
the day on Wednesday, along with deep boundary layer mixing,
ample sunshine, and gusty south winds all point to a hot day on
Wednesday. Temperatures are likely to rise well into the 90s, and
while the mixing will be deep the airmass above the mixed layer
will be quite moist and dewpoints may remain in the upper 60s to
lower 70s through the day. This will result in the heat index
ranging from 100 to 105 with some potential to climb into the
105-110 range depending on the eventual dewpoints. A building cap
through the day will prevent any thunderstorm activity through
Thursday morning. Thursday morning lows will be very warm in the
70s, setting the stage for another hot day. A cold front will
approach the area from the northwest by late in the day on
Thursday as a strong trough moves through North Dakota. Current
model timing suggests the front will enter the forecast area by
mid afternoon on Thursday with a thermal ridge immediately in
advance of the front and another well-mixed boundary layer.
Thursday should at least have somewhat drier air available to mix
down to the surface so while temperatures may be a bit warmer, the
dewpoints should be a bit lower. The end result will be a heat
index in the 98-105 range although it seems that Thursday has some
potential to be hotter than the current forecast depending on
frontal timing.

The strongest instability and forcing is expected to be northeast
of the area over Iowa where dewpoints will be higher on Thursday,
but convergence along the front should be sufficient for at least
a chance of thunderstorms by late afternoon into the evening in
northern Kansas. Wind shear will be very weak but with the hot
conditions could see a localized damaging wind threat materialize.
As the low level jet intensifies a bit through the evening, may
see increased thunderstorm coverage despite the LLJ being largely
parallel to the front. Some model guidance is quite aggressive in
producing widespread precip, but with the parallel LLJ and a lack
of strong forcing aloft have trended POPs a bit lower through
Friday morning...although still a fair chance. The front will hang
up over central/southern KS on Friday with faster westerly flow
moving overhead along with embedded weak short wave troughs. This
points to periodic chances for thunderstorms into Friday night,
with chances decreasing during the day on Saturday as the front
continues to push farther south. Then have a dry forecast for
Saturday night into Sunday before troughing builds into the
western CONUS and return flow brings a moisture surge back north
with renewed thunderstorm chances for Monday. Post-frontal
temperatures Friday through Sunday will be much cooler, with highs
likely only in the 70s and lows into the 50s. The main uncertainty
in eventual temperatures will be the density of cloud cover, but
can say with confidence that it will be well below normal this
weekend.

&&

.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1219 PM CDT TUE SEP 2 2014

For the 18z TAFs, the IFR/MVFR stratus from this morning is
gradually scattering out and will push further south of the
KTOP/KFOE early this afternoon. Winds will remain light and variable
into this evening as surface high pressure shifts over the region.
There is the potential for scattered thunderstorms to develop near
the TAF sites overnight into Wednesday morning as a warm front lifts
northward into the region. Have just a mention of VCTS at this time
due to uncertainty still in the timing and location of this
activity. Some models are suggesting that VIS may be reduced to
MVFR/IFR conditions at times with these scattered thunderstorms. Did
not include with this TAF issuance, but will continue to monitor
this potential in future updates.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Hennecke







000
FXUS63 KTOP 021139
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
639 AM CDT Tue Sep 2 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 312 AM CDT TUE SEP 2 2014

Analysis at 08Z depicts the upper trough axis rotating through Iowa
and Minnesota. Meanwhile the stationary front was positioned from
southwest to northeast over eastern KS. Scattered thunderstorms have
been ongoing for the past several hours as a result of this
boundary. Convection is expected to track south and east away from
the CWA this morning. Clearing skies along and north of the boundary
where dewpoints reside in the upper 60s and low 70s may develop
patchy fog through sunrise. Scattered mid level clouds and surface
winds remaining slightly mixed in some locations should prohibit
widespread development. Areas south of Interstate 70 see the best
chance for patchy fog to form and lift shortly after sunrise.

Light winds and mostly sunny skies reside for much of the afternoon
with highs in the middle to upper 80s. Focus turns to thunderstorm
chances beginning late this afternoon as the aforementioned
stationary front lifts northward as a warm front through east central
KS. Moisture pools along and north of the boundary with dewpoints
progged near 70 degrees. MLCAPE gradient tightens after 21Z with
latest guidance averaging near 3000 J/KG. Main question for this
afternoon is the strength of the capping inversion. Contrary to the
guidance consensus, the past runs of the NAM show a much weaker cap
near the boundary, initiating thunderstorms mainly along and south
of I 70 between 21Z and 03Z. Confidence is marginal on storms
developing during the late afternoon with increased chances this
evening as the veering LLJ transports deeper moisture into the area.
The stronger updrafts will be capable of large hail and isolated
strong wind gusts through early evening. Expect activity to weaken
as it tracks towards western Missouri by Wednesday morning. Cloud
cover within the warm sector tonight should limit lows to the upper
60s.

.LONG TERM...(Wednesday through Monday)
Issued at 312 AM CDT TUE SEP 2 2014

Forecast highlights in the long term include hot temperatures and
heat index on Wednesday and perhaps into Thursday, timing of a
front and associated precipitation chances late Thursday into the
weekend, and a significant cool down behind the front.

Any remnant thunderstorms should be quick to move east of the area
on Wednesday morning. Warm advection through the night and into
the day on Wednesday, along with deep boundary layer mixing,
ample sunshine, and gusty south winds all point to a hot day on
Wednesday. Temperatures are likely to rise well into the 90s, and
while the mixing will be deep the airmass above the mixed layer
will be quite moist and dewpoints may remain in the upper 60s to
lower 70s through the day. This will result in the heat index
ranging from 100 to 105 with some potential to climb into the
105-110 range depending on the eventual dewpoints. A building cap
through the day will prevent any thunderstorm activity through
Thursday morning. Thursday morning lows will be very warm in the
70s, setting the stage for another hot day. A cold front will
approach the area from the northwest by late in the day on
Thursday as a strong trough moves through North Dakota. Current
model timing suggests the front will enter the forecast area by
mid afternoon on Thursday with a thermal ridge immediately in
advance of the front and another well-mixed boundary layer.
Thursday should at least have somewhat drier air available to mix
down to the surface so while temperatures may be a bit warmer, the
dewpoints should be a bit lower. The end result will be a heat
index in the 98-105 range although it seems that Thursday has some
potential to be hotter than the current forecast depending on
frontal timing.

The strongest instability and forcing is expected to be northeast
of the area over Iowa where dewpoints will be higher on Thursday,
but convergence along the front should be sufficient for at least
a chance of thunderstorms by late afternoon into the evening in
northern Kansas. Wind shear will be very weak but with the hot
conditions could see a localized damaging wind threat materialize.
As the low level jet intensifies a bit through the evening, may
see increased thunderstorm coverage despite the LLJ being largely
parallel to the front. Some model guidance is quite aggressive in
producing widespread precip, but with the parallel LLJ and a lack
of strong forcing aloft have trended POPs a bit lower through
Friday morning...although still a fair chance. The front will hang
up over central/southern KS on Friday with faster westerly flow
moving overhead along with embedded weak short wave troughs. This
points to periodic chances for thunderstorms into Friday night,
with chances decreasing during the day on Saturday as the front
continues to push farther south. Then have a dry forecast for
Saturday night into Sunday before troughing builds into the
western CONUS and return flow brings a moisture surge back north
with renewed thunderstorm chances for Monday. Post-frontal
temperatures Friday through Sunday will be much cooler, with highs
likely only in the 70s and lows into the 50s. The main uncertainty
in eventual temperatures will be the density of cloud cover, but
can say with confidence that it will be well below normal this
weekend.

&&

.AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning)
Issued at 630 AM CDT TUE SEP 2 2014

Dense fog at KTOP/KFOE is expected to quickly lift shortly after
sunrise from LIFR to VFR by 14Z. VFR conditions prevail
as a warm front shifts winds to the east and southeast at or
below 10 kts. Thunderstorms in the area are possible aft
06Z...however exact timing and location are uncertain at this time.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Bowen








000
FXUS63 KTOP 021139
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
639 AM CDT Tue Sep 2 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 312 AM CDT TUE SEP 2 2014

Analysis at 08Z depicts the upper trough axis rotating through Iowa
and Minnesota. Meanwhile the stationary front was positioned from
southwest to northeast over eastern KS. Scattered thunderstorms have
been ongoing for the past several hours as a result of this
boundary. Convection is expected to track south and east away from
the CWA this morning. Clearing skies along and north of the boundary
where dewpoints reside in the upper 60s and low 70s may develop
patchy fog through sunrise. Scattered mid level clouds and surface
winds remaining slightly mixed in some locations should prohibit
widespread development. Areas south of Interstate 70 see the best
chance for patchy fog to form and lift shortly after sunrise.

Light winds and mostly sunny skies reside for much of the afternoon
with highs in the middle to upper 80s. Focus turns to thunderstorm
chances beginning late this afternoon as the aforementioned
stationary front lifts northward as a warm front through east central
KS. Moisture pools along and north of the boundary with dewpoints
progged near 70 degrees. MLCAPE gradient tightens after 21Z with
latest guidance averaging near 3000 J/KG. Main question for this
afternoon is the strength of the capping inversion. Contrary to the
guidance consensus, the past runs of the NAM show a much weaker cap
near the boundary, initiating thunderstorms mainly along and south
of I 70 between 21Z and 03Z. Confidence is marginal on storms
developing during the late afternoon with increased chances this
evening as the veering LLJ transports deeper moisture into the area.
The stronger updrafts will be capable of large hail and isolated
strong wind gusts through early evening. Expect activity to weaken
as it tracks towards western Missouri by Wednesday morning. Cloud
cover within the warm sector tonight should limit lows to the upper
60s.

.LONG TERM...(Wednesday through Monday)
Issued at 312 AM CDT TUE SEP 2 2014

Forecast highlights in the long term include hot temperatures and
heat index on Wednesday and perhaps into Thursday, timing of a
front and associated precipitation chances late Thursday into the
weekend, and a significant cool down behind the front.

Any remnant thunderstorms should be quick to move east of the area
on Wednesday morning. Warm advection through the night and into
the day on Wednesday, along with deep boundary layer mixing,
ample sunshine, and gusty south winds all point to a hot day on
Wednesday. Temperatures are likely to rise well into the 90s, and
while the mixing will be deep the airmass above the mixed layer
will be quite moist and dewpoints may remain in the upper 60s to
lower 70s through the day. This will result in the heat index
ranging from 100 to 105 with some potential to climb into the
105-110 range depending on the eventual dewpoints. A building cap
through the day will prevent any thunderstorm activity through
Thursday morning. Thursday morning lows will be very warm in the
70s, setting the stage for another hot day. A cold front will
approach the area from the northwest by late in the day on
Thursday as a strong trough moves through North Dakota. Current
model timing suggests the front will enter the forecast area by
mid afternoon on Thursday with a thermal ridge immediately in
advance of the front and another well-mixed boundary layer.
Thursday should at least have somewhat drier air available to mix
down to the surface so while temperatures may be a bit warmer, the
dewpoints should be a bit lower. The end result will be a heat
index in the 98-105 range although it seems that Thursday has some
potential to be hotter than the current forecast depending on
frontal timing.

The strongest instability and forcing is expected to be northeast
of the area over Iowa where dewpoints will be higher on Thursday,
but convergence along the front should be sufficient for at least
a chance of thunderstorms by late afternoon into the evening in
northern Kansas. Wind shear will be very weak but with the hot
conditions could see a localized damaging wind threat materialize.
As the low level jet intensifies a bit through the evening, may
see increased thunderstorm coverage despite the LLJ being largely
parallel to the front. Some model guidance is quite aggressive in
producing widespread precip, but with the parallel LLJ and a lack
of strong forcing aloft have trended POPs a bit lower through
Friday morning...although still a fair chance. The front will hang
up over central/southern KS on Friday with faster westerly flow
moving overhead along with embedded weak short wave troughs. This
points to periodic chances for thunderstorms into Friday night,
with chances decreasing during the day on Saturday as the front
continues to push farther south. Then have a dry forecast for
Saturday night into Sunday before troughing builds into the
western CONUS and return flow brings a moisture surge back north
with renewed thunderstorm chances for Monday. Post-frontal
temperatures Friday through Sunday will be much cooler, with highs
likely only in the 70s and lows into the 50s. The main uncertainty
in eventual temperatures will be the density of cloud cover, but
can say with confidence that it will be well below normal this
weekend.

&&

.AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning)
Issued at 630 AM CDT TUE SEP 2 2014

Dense fog at KTOP/KFOE is expected to quickly lift shortly after
sunrise from LIFR to VFR by 14Z. VFR conditions prevail
as a warm front shifts winds to the east and southeast at or
below 10 kts. Thunderstorms in the area are possible aft
06Z...however exact timing and location are uncertain at this time.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Bowen







000
FXUS63 KTOP 020854
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
354 AM CDT Tue Sep 2 2014

.SHORT TERM...(Today and Tonight)
Issued at 312 AM CDT TUE SEP 2 2014

Analysis at 08Z depicts the upper trough axis rotating through Iowa
and Minnesota. Meanwhile the stationary front was positioned from
southwest to northeast over eastern KS. Scattered thunderstorms have
been ongoing for the past several hours as a result of this
boundary. Convection is expected to track south and east away from
the CWA this morning. Clearing skies along and north of the boundary
where dewpoints reside in the upper 60s and low 70s may develop
patchy fog through sunrise. Scattered mid level clouds and surface
winds remaining slightly mixed in some locations should prohibit
widespread development. Areas south of Interstate 70 see the best
chance for patchy fog to form and lift shortly after sunrise.

Light winds and mostly sunny skies reside for much of the afternoon
with highs in the middle to upper 80s. Focus turns to thunderstorm
chances beginning late this afternoon as the aforementioned
stationary front lifts northward as a warm front through east central
KS. Moisture pools along and north of the boundary with dewpoints
progged near 70 degrees. MLCAPE gradient tightens after 21Z with
latest guidance averaging near 3000 J/KG. Main question for this
afternoon is the strength of the capping inversion. Contrary to the
guidance consensus, the past runs of the NAM show a much weaker cap
near the boundary, initiating thunderstorms mainly along and south
of I 70 between 21Z and 03Z. Confidence is marginal on storms
developing during the late afternoon with increased chances this
evening as the veering LLJ transports deeper moisture into the area.
The stronger updrafts will be capable of large hail and isolated
strong wind gusts through early evening. Expect activity to weaken
as it tracks towards western Missouri by Wednesday morning. Cloud
cover within the warm sector tonight should limit lows to the upper
60s.

.LONG TERM...(Wednesday through Monday)
Issued at 312 AM CDT TUE SEP 2 2014

Forecast highlights in the long term include hot temperatures and
heat index on Wednesday and perhaps into Thursday, timing of a
front and associated precipitation chances late Thursday into the
weekend, and a significant cool down behind the front.

Any remnant thunderstorms should be quick to move east of the area
on Wednesday morning. Warm advection through the night and into
the day on Wednesday, along with deep boundary layer mixing,
ample sunshine, and gusty south winds all point to a hot day on
Wednesday. Temperatures are likely to rise well into the 90s, and
while the mixing will be deep the airmass above the mixed layer
will be quite moist and dewpoints may remain in the upper 60s to
lower 70s through the day. This will result in the heat index
ranging from 100 to 105 with some potential to climb into the
105-110 range depending on the eventual dewpoints. A building cap
through the day will prevent any thunderstorm activity through
Thursday morning. Thursday morning lows will be very warm in the
70s, setting the stage for another hot day. A cold front will
approach the area from the northwest by late in the day on
Thursday as a strong trough moves through North Dakota. Current
model timing suggests the front will enter the forecast area by
mid afternoon on Thursday with a thermal ridge immediately in
advance of the front and another well-mixed boundary layer.
Thursday should at least have somewhat drier air available to mix
down to the surface so while temperatures may be a bit warmer, the
dewpoints should be a bit lower. The end result will be a heat
index in the 98-105 range although it seems that Thursday has some
potential to be hotter than the current forecast depending on
frontal timing.

The strongest instability and forcing is expected to be northeast
of the area over Iowa where dewpoints will be higher on Thursday,
but convergence along the front should be sufficient for at least
a chance of thunderstorms by late afternoon into the evening in
northern Kansas. Wind shear will be very weak but with the hot
conditions could see a localized damaging wind threat materialize.
As the low level jet intensifies a bit through the evening, may
see increased thunderstorm coverage despite the LLJ being largely
parallel to the front. Some model guidance is quite aggressive in
producing widespread precip, but with the parallel LLJ and a lack
of strong forcing aloft have trended POPs a bit lower through
Friday morning...although still a fair chance. The front will hang
up over central/southern KS on Friday with faster westerly flow
moving overhead along with embedded weak short wave troughs. This
points to periodic chances for thunderstorms into Friday night,
with chances decreasing during the day on Saturday as the front
continues to push farther south. Then have a dry forecast for
Saturday night into Sunday before troughing builds into the
western CONUS and return flow brings a moisture surge back north
with renewed thunderstorm chances for Monday. Post-frontal
temperatures Friday through Sunday will be much cooler, with highs
likely only in the 70s and lows into the 50s. The main uncertainty
in eventual temperatures will be the density of cloud cover, but
can say with confidence that it will be well below normal this
weekend.

&&

.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1149 PM CDT MON SEP 1 2014

Elevated thunderstorms have moved well south and east of the taf
sites. Mid and high level clouds have blanketed the area from the
convection in southern KS, but they are slowly progressing
eastward. Once the clouds clear out there maybe brief periods of
patchy especially during calm winds in the predawn hours. Although the
forecast winds just above the surface may inhibit fog development.
Therefore did not add any tempo for dense fog at this time.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Sanders







000
FXUS63 KTOP 020854
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
354 AM CDT Tue Sep 2 2014

.SHORT TERM...(Today and Tonight)
Issued at 312 AM CDT TUE SEP 2 2014

Analysis at 08Z depicts the upper trough axis rotating through Iowa
and Minnesota. Meanwhile the stationary front was positioned from
southwest to northeast over eastern KS. Scattered thunderstorms have
been ongoing for the past several hours as a result of this
boundary. Convection is expected to track south and east away from
the CWA this morning. Clearing skies along and north of the boundary
where dewpoints reside in the upper 60s and low 70s may develop
patchy fog through sunrise. Scattered mid level clouds and surface
winds remaining slightly mixed in some locations should prohibit
widespread development. Areas south of Interstate 70 see the best
chance for patchy fog to form and lift shortly after sunrise.

Light winds and mostly sunny skies reside for much of the afternoon
with highs in the middle to upper 80s. Focus turns to thunderstorm
chances beginning late this afternoon as the aforementioned
stationary front lifts northward as a warm front through east central
KS. Moisture pools along and north of the boundary with dewpoints
progged near 70 degrees. MLCAPE gradient tightens after 21Z with
latest guidance averaging near 3000 J/KG. Main question for this
afternoon is the strength of the capping inversion. Contrary to the
guidance consensus, the past runs of the NAM show a much weaker cap
near the boundary, initiating thunderstorms mainly along and south
of I 70 between 21Z and 03Z. Confidence is marginal on storms
developing during the late afternoon with increased chances this
evening as the veering LLJ transports deeper moisture into the area.
The stronger updrafts will be capable of large hail and isolated
strong wind gusts through early evening. Expect activity to weaken
as it tracks towards western Missouri by Wednesday morning. Cloud
cover within the warm sector tonight should limit lows to the upper
60s.

.LONG TERM...(Wednesday through Monday)
Issued at 312 AM CDT TUE SEP 2 2014

Forecast highlights in the long term include hot temperatures and
heat index on Wednesday and perhaps into Thursday, timing of a
front and associated precipitation chances late Thursday into the
weekend, and a significant cool down behind the front.

Any remnant thunderstorms should be quick to move east of the area
on Wednesday morning. Warm advection through the night and into
the day on Wednesday, along with deep boundary layer mixing,
ample sunshine, and gusty south winds all point to a hot day on
Wednesday. Temperatures are likely to rise well into the 90s, and
while the mixing will be deep the airmass above the mixed layer
will be quite moist and dewpoints may remain in the upper 60s to
lower 70s through the day. This will result in the heat index
ranging from 100 to 105 with some potential to climb into the
105-110 range depending on the eventual dewpoints. A building cap
through the day will prevent any thunderstorm activity through
Thursday morning. Thursday morning lows will be very warm in the
70s, setting the stage for another hot day. A cold front will
approach the area from the northwest by late in the day on
Thursday as a strong trough moves through North Dakota. Current
model timing suggests the front will enter the forecast area by
mid afternoon on Thursday with a thermal ridge immediately in
advance of the front and another well-mixed boundary layer.
Thursday should at least have somewhat drier air available to mix
down to the surface so while temperatures may be a bit warmer, the
dewpoints should be a bit lower. The end result will be a heat
index in the 98-105 range although it seems that Thursday has some
potential to be hotter than the current forecast depending on
frontal timing.

The strongest instability and forcing is expected to be northeast
of the area over Iowa where dewpoints will be higher on Thursday,
but convergence along the front should be sufficient for at least
a chance of thunderstorms by late afternoon into the evening in
northern Kansas. Wind shear will be very weak but with the hot
conditions could see a localized damaging wind threat materialize.
As the low level jet intensifies a bit through the evening, may
see increased thunderstorm coverage despite the LLJ being largely
parallel to the front. Some model guidance is quite aggressive in
producing widespread precip, but with the parallel LLJ and a lack
of strong forcing aloft have trended POPs a bit lower through
Friday morning...although still a fair chance. The front will hang
up over central/southern KS on Friday with faster westerly flow
moving overhead along with embedded weak short wave troughs. This
points to periodic chances for thunderstorms into Friday night,
with chances decreasing during the day on Saturday as the front
continues to push farther south. Then have a dry forecast for
Saturday night into Sunday before troughing builds into the
western CONUS and return flow brings a moisture surge back north
with renewed thunderstorm chances for Monday. Post-frontal
temperatures Friday through Sunday will be much cooler, with highs
likely only in the 70s and lows into the 50s. The main uncertainty
in eventual temperatures will be the density of cloud cover, but
can say with confidence that it will be well below normal this
weekend.

&&

.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1149 PM CDT MON SEP 1 2014

Elevated thunderstorms have moved well south and east of the taf
sites. Mid and high level clouds have blanketed the area from the
convection in southern KS, but they are slowly progressing
eastward. Once the clouds clear out there maybe brief periods of
patchy especially during calm winds in the predawn hours. Although the
forecast winds just above the surface may inhibit fog development.
Therefore did not add any tempo for dense fog at this time.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Bowen
LONG TERM...Barjenbruch
AVIATION...Sanders








000
FXUS63 KTOP 020455
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1155 PM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014

Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.

Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.

.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014

Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.

With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.

Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.

&&

.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1149 PM CDT MON SEP 1 2014

Elevated thunderstorms have moved well south and east of the taf
sites. Mid and high level clouds have blanketed the area from the
convection in southern KS, but they are slowly progressing
eastward. Once the clouds clear out there maybe brief periods of
patchy especially during calm winds in the predawn hours. Although the
forecast winds just above the surface may inhibit fog development.
Therefore did not add any tempo for dense fog at this time.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders







000
FXUS63 KTOP 020455
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1155 PM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014

Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.

Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.

.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014

Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.

With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.

Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.

&&

.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1149 PM CDT MON SEP 1 2014

Elevated thunderstorms have moved well south and east of the taf
sites. Mid and high level clouds have blanketed the area from the
convection in southern KS, but they are slowly progressing
eastward. Once the clouds clear out there maybe brief periods of
patchy especially during calm winds in the predawn hours. Although the
forecast winds just above the surface may inhibit fog development.
Therefore did not add any tempo for dense fog at this time.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders








000
FXUS63 KTOP 012355
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
655 PM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014

Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.

Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.

.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014

Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.

With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.

Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.

&&

.AVIATION...(For the 00Z TAFs through 00Z Tuesday Evening)
Issued at 634 PM CDT MON SEP 1 2014

Fog at the taf sites later tonight will be the biggest issue with
this forecast period. The low stratus deck which has been around
this afternoon is very slow to progress anywhere. Current
satellite image shows higher cumulus building northward from south
central KS so clearing may be delayed. Also elevated showers are
possible this evening as evident from latest radar although the
models were much further south. These showers could approach MHK
in the next hour. If the clouds are able to clear out later this
evening then the potential for dense fog will be higher.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders








000
FXUS63 KTOP 012355
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
655 PM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014

Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.

Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.

.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014

Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.

With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.

Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.

&&

.AVIATION...(For the 00Z TAFs through 00Z Tuesday Evening)
Issued at 634 PM CDT MON SEP 1 2014

Fog at the taf sites later tonight will be the biggest issue with
this forecast period. The low stratus deck which has been around
this afternoon is very slow to progress anywhere. Current
satellite image shows higher cumulus building northward from south
central KS so clearing may be delayed. Also elevated showers are
possible this evening as evident from latest radar although the
models were much further south. These showers could approach MHK
in the next hour. If the clouds are able to clear out later this
evening then the potential for dense fog will be higher.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders







000
FXUS63 KTOP 012019
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
319 PM CDT Mon Sep 1 2014

.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014

Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.

Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.

.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014

Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.

With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.

Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.

&&

.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1251 PM CDT MON SEP 1 2014

Appears convective concerns at TOP and FOE are somewhat lower than
earlier expectations with persistent cloud keeping instability in
check and area of convergence near passing boundary should be
south before instability develops. Flow behind the boundary should
clear skies somewhat allowing for decent radiational fog setup
around 11Z. Have introduced MVFR BR at this point.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...65








000
FXUS63 KTOP 012019
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
319 PM CDT Mon Sep 1 2014

.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014

Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.

Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.

.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014

Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.

With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.

Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.

&&

.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1251 PM CDT MON SEP 1 2014

Appears convective concerns at TOP and FOE are somewhat lower than
earlier expectations with persistent cloud keeping instability in
check and area of convergence near passing boundary should be
south before instability develops. Flow behind the boundary should
clear skies somewhat allowing for decent radiational fog setup
around 11Z. Have introduced MVFR BR at this point.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...65







000
FXUS63 KTOP 011751
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1251 PM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT MON SEP 1 2014

Water vapor imagery showed a broad mid-level trough in place
across the northern U.S. with the shortwave trough that has helped
to support the overnight shower and thunderstorm activity early
this morning centered over the forecast area and shifting
eastward. The cold front associated with this storm system has
been lagging behind the precipitation, with it stretched across
north central Kansas as of 08z. Models still seem to be a bit fast
with the tracking of this frontal passage, but in general expect
it to slowly progress eastward through the day before getting hung
up across east central and southeastern Kansas as the southern
edge of the mid-level trough flattens but continues to dig a bit
further south over the region. With this eastward progression of
the front, will continue to see the widespread showers and
thunderstorms diminish from west to east this morning, with
possibly a few lingering showers over far east central Kansas by
mid-morning. Several short-range models suggest that areas in east
central Kansas may continue to see some isolated showers and
thunderstorms throughout the day as the front stalls over that
area. With this lingering boundary, expect to see a spread in high
temperatures from the low/mid 80s north to the upper 80s/near 90
degrees over east central Kansas where a southerly flow should
prevail for much of the day. This better diurnal heating over east
central Kansas should aid in modest instability developing across
the area this afternoon, which should support additional
thunderstorm development. This initial scattered activity should
become a bit more widespread along the boundary by mid to late
afternoon and into this evening, primarily along and south of I-35
but may extend as far north as around I-70. Severe thunderstorms
will be possible with this activity as MLCAPE values reach upwards
of 2000-3000J/kg with strong 0-6km bulk shear values of 45-55kts.
The primary concerns with these storms will be large hail and
damaging winds, but cannot rule out an isolated tornado threat.
Additionally, there is the potential for localized flooding as
additional moderate to heavy rain is possible over locations that
have already received a few inches of rain from this morning`s
thunderstorms. These storms should diminish during the late
evening hours and shift southward as the cold front gets pushed
south of the forecast area. With light northerly winds and
clearing skies behind this front, expect cooler conditions
overnight with lows dropping into the upper 50s north to mid/upper
60s south.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM CDT MON SEP 1 2014

The frontal boundary will remain hung up just south of the area on
Tuesday, and model guidance hints at a weak trough moving across
southern KS late in the day. Expect strong instability in east
central and southeast KS with little to no inhibition and 25 to 35
kts of 0-6 km shear. Low-level convergence will be very weak
however, and any thunderstorm development will have to rely on
lift from any weak mid level troughs. Currently have rather low
POPs focused in the far southern portions of the forecast area for
Tuesday afternoon, but if a slightly stronger disturbance can
bring some vertical motion into the area around peak heating,
could see scattered severe storms south of I-70. A strong trough
will move into Montana on Tuesday night with the low level jet
increasing a bit locally overnight. Expect impressive theta-e
advection and moisture transport into east central Kansas and
eventually northeast Kansas overnight. Steep mid-level lapse rates
will be in place with MUCAPE around 2000 J/kg and effective shear
of 30-40 kts. This should result in scattered to widespread
thunderstorms with large hail possible. Could also see a heavy
rain threat materialize.

Warm advection and ample sunshine by Wednesday point to a hot day
with heat index values possibly topping 100. The warm advection
aloft should also cap surface parcels and expect dry conditions
through Thursday. However, by late in the day on Thursday, a cold
front associated with the northern CONUS trough will approach the
area. Expect strong forcing along the front to result in
widespread thunderstorm development with the main uncertainty
still being the timing of the frontal progression across the
forecast area. The frontal zone seems likely to linger in the area
into the weekend as the main forcing will pass well north. This
will likely be impacted by any organized thunderstorm outflow
though. Elevated instability will remain in place north of the
front although it should diminish over time. Have gradually
decreased precip chances north to south through the weekend as the
surface high should build in stronger with time. Have not made
major changes to temperatures from the prior forecast, and we
still look to be on track for highs in the 70s for next weekend.

&&

.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1251 PM CDT MON SEP 1 2014

Appears convective concerns at TOP and FOE are somewhat lower than
earlier expectations with persistent cloud keeping instability in
check and area of convergence near passing boundary should be
south before instability develops. Flow behind the boundary should
clear skies somewhat allowing for decent radiational fog setup
around 11Z. Have introduced MVFR BR at this point.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...65







000
FXUS63 KTOP 011751
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1251 PM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT MON SEP 1 2014

Water vapor imagery showed a broad mid-level trough in place
across the northern U.S. with the shortwave trough that has helped
to support the overnight shower and thunderstorm activity early
this morning centered over the forecast area and shifting
eastward. The cold front associated with this storm system has
been lagging behind the precipitation, with it stretched across
north central Kansas as of 08z. Models still seem to be a bit fast
with the tracking of this frontal passage, but in general expect
it to slowly progress eastward through the day before getting hung
up across east central and southeastern Kansas as the southern
edge of the mid-level trough flattens but continues to dig a bit
further south over the region. With this eastward progression of
the front, will continue to see the widespread showers and
thunderstorms diminish from west to east this morning, with
possibly a few lingering showers over far east central Kansas by
mid-morning. Several short-range models suggest that areas in east
central Kansas may continue to see some isolated showers and
thunderstorms throughout the day as the front stalls over that
area. With this lingering boundary, expect to see a spread in high
temperatures from the low/mid 80s north to the upper 80s/near 90
degrees over east central Kansas where a southerly flow should
prevail for much of the day. This better diurnal heating over east
central Kansas should aid in modest instability developing across
the area this afternoon, which should support additional
thunderstorm development. This initial scattered activity should
become a bit more widespread along the boundary by mid to late
afternoon and into this evening, primarily along and south of I-35
but may extend as far north as around I-70. Severe thunderstorms
will be possible with this activity as MLCAPE values reach upwards
of 2000-3000J/kg with strong 0-6km bulk shear values of 45-55kts.
The primary concerns with these storms will be large hail and
damaging winds, but cannot rule out an isolated tornado threat.
Additionally, there is the potential for localized flooding as
additional moderate to heavy rain is possible over locations that
have already received a few inches of rain from this morning`s
thunderstorms. These storms should diminish during the late
evening hours and shift southward as the cold front gets pushed
south of the forecast area. With light northerly winds and
clearing skies behind this front, expect cooler conditions
overnight with lows dropping into the upper 50s north to mid/upper
60s south.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM CDT MON SEP 1 2014

The frontal boundary will remain hung up just south of the area on
Tuesday, and model guidance hints at a weak trough moving across
southern KS late in the day. Expect strong instability in east
central and southeast KS with little to no inhibition and 25 to 35
kts of 0-6 km shear. Low-level convergence will be very weak
however, and any thunderstorm development will have to rely on
lift from any weak mid level troughs. Currently have rather low
POPs focused in the far southern portions of the forecast area for
Tuesday afternoon, but if a slightly stronger disturbance can
bring some vertical motion into the area around peak heating,
could see scattered severe storms south of I-70. A strong trough
will move into Montana on Tuesday night with the low level jet
increasing a bit locally overnight. Expect impressive theta-e
advection and moisture transport into east central Kansas and
eventually northeast Kansas overnight. Steep mid-level lapse rates
will be in place with MUCAPE around 2000 J/kg and effective shear
of 30-40 kts. This should result in scattered to widespread
thunderstorms with large hail possible. Could also see a heavy
rain threat materialize.

Warm advection and ample sunshine by Wednesday point to a hot day
with heat index values possibly topping 100. The warm advection
aloft should also cap surface parcels and expect dry conditions
through Thursday. However, by late in the day on Thursday, a cold
front associated with the northern CONUS trough will approach the
area. Expect strong forcing along the front to result in
widespread thunderstorm development with the main uncertainty
still being the timing of the frontal progression across the
forecast area. The frontal zone seems likely to linger in the area
into the weekend as the main forcing will pass well north. This
will likely be impacted by any organized thunderstorm outflow
though. Elevated instability will remain in place north of the
front although it should diminish over time. Have gradually
decreased precip chances north to south through the weekend as the
surface high should build in stronger with time. Have not made
major changes to temperatures from the prior forecast, and we
still look to be on track for highs in the 70s for next weekend.

&&

.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1251 PM CDT MON SEP 1 2014

Appears convective concerns at TOP and FOE are somewhat lower than
earlier expectations with persistent cloud keeping instability in
check and area of convergence near passing boundary should be
south before instability develops. Flow behind the boundary should
clear skies somewhat allowing for decent radiational fog setup
around 11Z. Have introduced MVFR BR at this point.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...65






000
FXUS63 KTOP 011119
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
619 AM CDT Mon Sep 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT MON SEP 1 2014

Water vapor imagery showed a broad mid-level trough in place
across the northern U.S. with the shortwave trough that has helped
to support the overnight shower and thunderstorm activity early
this morning centered over the forecast area and shifting
eastward. The cold front associated with this storm system has
been lagging behind the precipitation, with it stretched across
north central Kansas as of 08z. Models still seem to be a bit fast
with the tracking of this frontal passage, but in general expect
it to slowly progress eastward through the day before getting hung
up across east central and southeastern Kansas as the southern
edge of the mid-level trough flattens but continues to dig a bit
further south over the region. With this eastward progression of
the front, will continue to see the widespread showers and
thunderstorms diminish from west to east this morning, with
possibly a few lingering showers over far east central Kansas by
mid-morning. Several short-range models suggest that areas in east
central Kansas may continue to see some isolated showers and
thunderstorms throughout the day as the front stalls over that
area. With this lingering boundary, expect to see a spread in high
temperatures from the low/mid 80s north to the upper 80s/near 90
degrees over east central Kansas where a southerly flow should
prevail for much of the day. This better diurnal heating over east
central Kansas should aid in modest instability developing across
the area this afternoon, which should support additional
thunderstorm development. This initial scattered activity should
become a bit more widespread along the boundary by mid to late
afternoon and into this evening, primarily along and south of I-35
but may extend as far north as around I-70. Severe thunderstorms
will be possible with this activity as MLCAPE values reach upwards
of 2000-3000J/kg with strong 0-6km bulk shear values of 45-55kts.
The primary concerns with these storms will be large hail and
damaging winds, but cannot rule out an isolated tornado threat.
Additionally, there is the potential for localized flooding as
additional moderate to heavy rain is possible over locations that
have already received a few inches of rain from this morning`s
thunderstorms. These storms should diminish during the late
evening hours and shift southward as the cold front gets pushed
south of the forecast area. With light northerly winds and
clearing skies behind this front, expect cooler conditions
overnight with lows dropping into the upper 50s north to mid/upper
60s south.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM CDT MON SEP 1 2014

The frontal boundary will remain hung up just south of the area on
Tuesday, and model guidance hints at a weak trough moving across
southern KS late in the day. Expect strong instability in east
central and southeast KS with little to no inhibition and 25 to 35
kts of 0-6 km shear. Low-level convergence will be very weak
however, and any thunderstorm development will have to rely on
lift from any weak mid level troughs. Currently have rather low
POPs focused in the far southern portions of the forecast area for
Tuesday afternoon, but if a slightly stronger disturbance can
bring some vertical motion into the area around peak heating,
could see scattered severe storms south of I-70. A strong trough
will move into Montana on Tuesday night with the low level jet
increasing a bit locally overnight. Expect impressive theta-e
advection and moisture transport into east central Kansas and
eventually northeast Kansas overnight. Steep mid-level lapse rates
will be in place with MUCAPE around 2000 J/kg and effective shear
of 30-40 kts. This should result in scattered to widespread
thunderstorms with large hail possible. Could also see a heavy
rain threat materialize.

Warm advection and ample sunshine by Wednesday point to a hot day
with heat index values possibly topping 100. The warm advection
aloft should also cap surface parcels and expect dry conditions
through Thursday. However, by late in the day on Thursday, a cold
front associated with the northern CONUS trough will approach the
area. Expect strong forcing along the front to result in
widespread thunderstorm development with the main uncertainty
still being the timing of the frontal progression across the
forecast area. The frontal zone seems likely to linger in the area
into the weekend as the main forcing will pass well north. This
will likely be impacted by any organized thunderstorm outflow
though. Elevated instability will remain in place north of the
front although it should diminish over time. Have gradually
decreased precip chances north to south through the weekend as the
surface high should build in stronger with time. Have not made
major changes to temperatures from the prior forecast, and we
still look to be on track for highs in the 70s for next weekend.

&&

.AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning)
Issued at 618 AM CDT MON SEP 1 2014

For the 12z TAFs, some scattered IFR/MVFR cigs have developed behind
the precipitation and should persist through the morning before
lifting to low-end VFR by this afternoon. As the cold front slowly
tracks through the region, winds will be veering to the northwest
and north-northeast through the period. There is the potential for
thunderstorms to redevelop by late afternoon near the lingering
boundary, however there is still some uncertainty as to whether or
not this activity will impact KTOP/KFOE so only have a mention of
VCTS at this time. Any storms that do develop should move further
south of the TAF sites through the evening. Models are starting to
suggest the possibility of some patchy fog developing Tuesday
morning due to the light winds, clearing skies, and low-level
moisture present. Mentioned a scattered MVFR cloud deck at this
time, but too much uncertainty still to add any further details in
the TAF.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...Hennecke








000
FXUS63 KTOP 010905
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
405 AM CDT Mon Sep 1 2014

.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT MON SEP 1 2014

Water vapor imagery showed a broad mid-level trough in place
across the northern U.S. with the shortwave trough that has helped
to support the overnight shower and thunderstorm activity early
this morning centered over the forecast area and shifting
eastward. The cold front associated with this storm system has
been lagging behind the precipitation, with it stretched across
north central Kansas as of 08z. Models still seem to be a bit fast
with the tracking of this frontal passage, but in general expect
it to slowly progress eastward through the day before getting hung
up across east central and southeastern Kansas as the southern
edge of the mid-level trough flattens but continues to dig a bit
further south over the region. With this eastward progression of
the front, will continue to see the widespread showers and
thunderstorms diminish from west to east this morning, with
possibly a few lingering showers over far east central Kansas by
mid-morning. Several short-range models suggest that areas in east
central Kansas may continue to see some isolated showers and
thunderstorms throughout the day as the front stalls over that
area. With this lingering boundary, expect to see a spread in high
temperatures from the low/mid 80s north to the upper 80s/near 90
degrees over east central Kansas where a southerly flow should
prevail for much of the day. This better diurnal heating over east
central Kansas should aid in modest instability developing across
the area this afternoon, which should support additional
thunderstorm development. This initial scattered activity should
become a bit more widespread along the boundary by mid to late
afternoon and into this evening, primarily along and south of I-35
but may extend as far north as around I-70. Severe thunderstorms
will be possible with this activity as MLCAPE values reach upwards
of 2000-3000J/kg with strong 0-6km bulk shear values of 45-55kts.
The primary concerns with these storms will be large hail and
damaging winds, but cannot rule out an isolated tornado threat.
Additionally, there is the potential for localized flooding as
additional moderate to heavy rain is possible over locations that
have already received a few inches of rain from this morning`s
thunderstorms. These storms should diminish during the late
evening hours and shift southward as the cold front gets pushed
south of the forecast area. With light northerly winds and
clearing skies behind this front, expect cooler conditions
overnight with lows dropping into the upper 50s north to mid/upper
60s south.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM CDT MON SEP 1 2014

The frontal boundary will remain hung up just south of the area on
Tuesday, and model guidance hints at a weak trough moving across
southern KS late in the day. Expect strong instability in east
central and southeast KS with little to no inhibition and 25 to 35
kts of 0-6 km shear. Low-level convergence will be very weak
however, and any thunderstorm development will have to rely on
lift from any weak mid level troughs. Currently have rather low
POPs focused in the far southern portions of the forecast area for
Tuesday afternoon, but if a slightly stronger disturbance can
bring some vertical motion into the area around peak heating,
could see scattered severe storms south of I-70. A strong trough
will move into Montana on Tuesday night with the low level jet
increasing a bit locally overnight. Expect impressive theta-e
advection and moisture transport into east central Kansas and
eventually northeast Kansas overnight. Steep mid-level lapse rates
will be in place with MUCAPE around 2000 J/kg and effective shear
of 30-40 kts. This should result in scattered to widespread
thunderstorms with large hail possible. Could also see a heavy
rain threat materialize.

Warm advection and ample sunshine by Wednesday point to a hot day
with heat index values possibly topping 100. The warm advection
aloft should also cap surface parcels and expect dry conditions
through Thursday. However, by late in the day on Thursday, a cold
front associated with the northern CONUS trough will approach the
area. Expect strong forcing along the front to result in
widespread thunderstorm development with the main uncertainty
still being the timing of the frontal progression across the
forecast area. The frontal zone seems likely to linger in the area
into the weekend as the main forcing will pass well north. This
will likely be impacted by any organized thunderstorm outflow
though. Elevated instability will remain in place north of the
front although it should diminish over time. Have gradually
decreased precip chances north to south through the weekend as the
surface high should build in stronger with time. Have not made
major changes to temperatures from the prior forecast, and we
still look to be on track for highs in the 70s for next weekend.

&&

.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1240 AM CDT MON SEP 1 2014

For the 06z TAFs, widespread showers and embedded thunderstorms will
persist through the overnight hours into Monday morning. Some models
are suggesting that areas of fog may develop before sunrise,
especially near KTOP/KFOE. There is still uncertainty with regards
to whether or not this will occur as winds may stay just high enough
to diminish this threat, but went ahead and added a TEMPO group at
this time and will continue to monitor the trends through the
overnight hours. Expect this precipitation to shift south of the TAF
sites during the morning hours with winds veering to the northwest
and eventually north-northeast with the frontal passage. There is a
chance for additional scattered thunderstorm develop late afternoon
into early evening. However, the TAF sites may be near the northern
edge of this precipitation development, so have only mentioned VCTS
at this time due to the uncertainty in the exact location of these
storms. Any storms that do develop near the TAF sites should shift
southward by mid to late evening.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...Hennecke








000
FXUS63 KTOP 010905
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
405 AM CDT Mon Sep 1 2014

.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT MON SEP 1 2014

Water vapor imagery showed a broad mid-level trough in place
across the northern U.S. with the shortwave trough that has helped
to support the overnight shower and thunderstorm activity early
this morning centered over the forecast area and shifting
eastward. The cold front associated with this storm system has
been lagging behind the precipitation, with it stretched across
north central Kansas as of 08z. Models still seem to be a bit fast
with the tracking of this frontal passage, but in general expect
it to slowly progress eastward through the day before getting hung
up across east central and southeastern Kansas as the southern
edge of the mid-level trough flattens but continues to dig a bit
further south over the region. With this eastward progression of
the front, will continue to see the widespread showers and
thunderstorms diminish from west to east this morning, with
possibly a few lingering showers over far east central Kansas by
mid-morning. Several short-range models suggest that areas in east
central Kansas may continue to see some isolated showers and
thunderstorms throughout the day as the front stalls over that
area. With this lingering boundary, expect to see a spread in high
temperatures from the low/mid 80s north to the upper 80s/near 90
degrees over east central Kansas where a southerly flow should
prevail for much of the day. This better diurnal heating over east
central Kansas should aid in modest instability developing across
the area this afternoon, which should support additional
thunderstorm development. This initial scattered activity should
become a bit more widespread along the boundary by mid to late
afternoon and into this evening, primarily along and south of I-35
but may extend as far north as around I-70. Severe thunderstorms
will be possible with this activity as MLCAPE values reach upwards
of 2000-3000J/kg with strong 0-6km bulk shear values of 45-55kts.
The primary concerns with these storms will be large hail and
damaging winds, but cannot rule out an isolated tornado threat.
Additionally, there is the potential for localized flooding as
additional moderate to heavy rain is possible over locations that
have already received a few inches of rain from this morning`s
thunderstorms. These storms should diminish during the late
evening hours and shift southward as the cold front gets pushed
south of the forecast area. With light northerly winds and
clearing skies behind this front, expect cooler conditions
overnight with lows dropping into the upper 50s north to mid/upper
60s south.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM CDT MON SEP 1 2014

The frontal boundary will remain hung up just south of the area on
Tuesday, and model guidance hints at a weak trough moving across
southern KS late in the day. Expect strong instability in east
central and southeast KS with little to no inhibition and 25 to 35
kts of 0-6 km shear. Low-level convergence will be very weak
however, and any thunderstorm development will have to rely on
lift from any weak mid level troughs. Currently have rather low
POPs focused in the far southern portions of the forecast area for
Tuesday afternoon, but if a slightly stronger disturbance can
bring some vertical motion into the area around peak heating,
could see scattered severe storms south of I-70. A strong trough
will move into Montana on Tuesday night with the low level jet
increasing a bit locally overnight. Expect impressive theta-e
advection and moisture transport into east central Kansas and
eventually northeast Kansas overnight. Steep mid-level lapse rates
will be in place with MUCAPE around 2000 J/kg and effective shear
of 30-40 kts. This should result in scattered to widespread
thunderstorms with large hail possible. Could also see a heavy
rain threat materialize.

Warm advection and ample sunshine by Wednesday point to a hot day
with heat index values possibly topping 100. The warm advection
aloft should also cap surface parcels and expect dry conditions
through Thursday. However, by late in the day on Thursday, a cold
front associated with the northern CONUS trough will approach the
area. Expect strong forcing along the front to result in
widespread thunderstorm development with the main uncertainty
still being the timing of the frontal progression across the
forecast area. The frontal zone seems likely to linger in the area
into the weekend as the main forcing will pass well north. This
will likely be impacted by any organized thunderstorm outflow
though. Elevated instability will remain in place north of the
front although it should diminish over time. Have gradually
decreased precip chances north to south through the weekend as the
surface high should build in stronger with time. Have not made
major changes to temperatures from the prior forecast, and we
still look to be on track for highs in the 70s for next weekend.

&&

.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1240 AM CDT MON SEP 1 2014

For the 06z TAFs, widespread showers and embedded thunderstorms will
persist through the overnight hours into Monday morning. Some models
are suggesting that areas of fog may develop before sunrise,
especially near KTOP/KFOE. There is still uncertainty with regards
to whether or not this will occur as winds may stay just high enough
to diminish this threat, but went ahead and added a TEMPO group at
this time and will continue to monitor the trends through the
overnight hours. Expect this precipitation to shift south of the TAF
sites during the morning hours with winds veering to the northwest
and eventually north-northeast with the frontal passage. There is a
chance for additional scattered thunderstorm develop late afternoon
into early evening. However, the TAF sites may be near the northern
edge of this precipitation development, so have only mentioned VCTS
at this time due to the uncertainty in the exact location of these
storms. Any storms that do develop near the TAF sites should shift
southward by mid to late evening.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...Hennecke







000
FXUS63 KTOP 010541
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1241 AM CDT Mon Sep 1 2014

.MESOSCALE DISCUSSION...
Issued at 1240 AM CDT MON SEP 1 2014

The midnight through 3 AM period will continue to see at least some
low end potential for marginally severe hail, and perhaps localized
damaging wind gusts in the strongest storms able to downburst and
transport momentum to the surface through the inversion (refer to
recent SPC mesoscale discussion for more details).

Aside from severe potential, the potential for flash flooding is
increasing and could see additional warnings needed during the
overnight hours. The outflow from the complex of storms has pushed
into southern Kansas and stretched west-to-east while the upper
trough and overall storm motion remains east southeast nearly
parallel to the effective boundary. Moisture transport is very
impressive into and over the frontal zone into central and east
central Kansas while precipitable water values are running 2 to 2.2
inches according to RAP analysis. Dual-pol signatures have at times
indicated very heavy rainfall rates to around 2" per hour with the
heaviest activity and spotters have reported 15-20 minute periods
with 1 to 1.5 inches of rain. The orientation of the front and storm
motion suggests training of individual convective updrafts over the
same areas from southern Dickinson through Morris, Lyon, Coffey,
Anderson, southern Osage and southern Franklin counties. Dual-pol
rain estimates as of midnight range from 4" in southern Dickinson
county to 2.5" in Lyon county to 2" in Osage/Franklin counties.
Given current trends and expectations, could end up seeing a broad
swatch of 2 to 5" with locally 6+ inches possible.

There are some indications that the rear edge of the convection is
beginning to forward propagate toward the southeast which may help
put a slightly faster end to the very heavy rain, but should
continue to see development in advance of the upper trough axis and
north of the outflow which could persist even behind any forward
propagating segments. This heavy precip is also falling across the
parts of the area that have been driest as of late, and can handle
more water. However, the torrential rates alone will produce
substantial runoff and may be sufficient for flash flooding even in
the dry conditions.

&&

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014

Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.

Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.

Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.

Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.

.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014

For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.

Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.

Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.

&&

.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1240 AM CDT MON SEP 1 2014

For the 06z TAFs, widespread showers and embedded thunderstorms will
persist through the overnight hours into Monday morning. Some models
are suggesting that areas of fog may develop before sunrise,
especially near KTOP/KFOE. There is still uncertainty with regards
to whether or not this will occur as winds may stay just high enough
to diminish this threat, but went ahead and added a TEMPO group at
this time and will continue to monitor the trends through the
overnight hours. Expect this precipitation to shift south of the TAF
sites during the morning hours with winds veering to the northwest
and eventually north-northeast with the frontal passage. There is a
chance for additional scattered thunderstorm develop late afternoon
into early evening. However, the TAF sites may be near the northern
edge of this precipitation development, so have only mentioned VCTS
at this time due to the uncertainty in the exact location of these
storms. Any storms that do develop near the TAF sites should shift
southward by mid to late evening.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

MESOSCALE...Barjenbruch
SHORT TERM...65
LONG TERM...Wolters
AVIATION...Hennecke







000
FXUS63 KTOP 010541
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1241 AM CDT Mon Sep 1 2014

.MESOSCALE DISCUSSION...
Issued at 1240 AM CDT MON SEP 1 2014

The midnight through 3 AM period will continue to see at least some
low end potential for marginally severe hail, and perhaps localized
damaging wind gusts in the strongest storms able to downburst and
transport momentum to the surface through the inversion (refer to
recent SPC mesoscale discussion for more details).

Aside from severe potential, the potential for flash flooding is
increasing and could see additional warnings needed during the
overnight hours. The outflow from the complex of storms has pushed
into southern Kansas and stretched west-to-east while the upper
trough and overall storm motion remains east southeast nearly
parallel to the effective boundary. Moisture transport is very
impressive into and over the frontal zone into central and east
central Kansas while precipitable water values are running 2 to 2.2
inches according to RAP analysis. Dual-pol signatures have at times
indicated very heavy rainfall rates to around 2" per hour with the
heaviest activity and spotters have reported 15-20 minute periods
with 1 to 1.5 inches of rain. The orientation of the front and storm
motion suggests training of individual convective updrafts over the
same areas from southern Dickinson through Morris, Lyon, Coffey,
Anderson, southern Osage and southern Franklin counties. Dual-pol
rain estimates as of midnight range from 4" in southern Dickinson
county to 2.5" in Lyon county to 2" in Osage/Franklin counties.
Given current trends and expectations, could end up seeing a broad
swatch of 2 to 5" with locally 6+ inches possible.

There are some indications that the rear edge of the convection is
beginning to forward propagate toward the southeast which may help
put a slightly faster end to the very heavy rain, but should
continue to see development in advance of the upper trough axis and
north of the outflow which could persist even behind any forward
propagating segments. This heavy precip is also falling across the
parts of the area that have been driest as of late, and can handle
more water. However, the torrential rates alone will produce
substantial runoff and may be sufficient for flash flooding even in
the dry conditions.

&&

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014

Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.

Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.

Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.

Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.

.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014

For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.

Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.

Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.

&&

.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1240 AM CDT MON SEP 1 2014

For the 06z TAFs, widespread showers and embedded thunderstorms will
persist through the overnight hours into Monday morning. Some models
are suggesting that areas of fog may develop before sunrise,
especially near KTOP/KFOE. There is still uncertainty with regards
to whether or not this will occur as winds may stay just high enough
to diminish this threat, but went ahead and added a TEMPO group at
this time and will continue to monitor the trends through the
overnight hours. Expect this precipitation to shift south of the TAF
sites during the morning hours with winds veering to the northwest
and eventually north-northeast with the frontal passage. There is a
chance for additional scattered thunderstorm develop late afternoon
into early evening. However, the TAF sites may be near the northern
edge of this precipitation development, so have only mentioned VCTS
at this time due to the uncertainty in the exact location of these
storms. Any storms that do develop near the TAF sites should shift
southward by mid to late evening.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

MESOSCALE...Barjenbruch
SHORT TERM...65
LONG TERM...Wolters
AVIATION...Hennecke








000
FXUS63 KTOP 312336
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
636 PM CDT Sun Aug 31 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014

Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.

Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.

Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.

Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.

.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014

For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.

Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.

Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.

&&

.AVIATION...(For the 00Z TAFs through 00Z Monday Evening)
Issued at 636 PM CDT SUN AUG 31 2014

Convective line timing remains the main concern. Line has still
not congealed with persistent outflow, but appears this process may
be occurring at this time. Have TS mention a bit earlier than
previously expected. Brief to periods of IFR visibilities are
likely given upstream obs. When to end TS is other concern with
additional storms currently behind the front. Have left timing of
this rather similar at this point but will have to monitor trends.
Front should be south of the terminals before redevelopment
occurs in peak heating Monday.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...65







000
FXUS63 KTOP 312336
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
636 PM CDT Sun Aug 31 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014

Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.

Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.

Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.

Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.

.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014

For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.

Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.

Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.

&&

.AVIATION...(For the 00Z TAFs through 00Z Monday Evening)
Issued at 636 PM CDT SUN AUG 31 2014

Convective line timing remains the main concern. Line has still
not congealed with persistent outflow, but appears this process may
be occurring at this time. Have TS mention a bit earlier than
previously expected. Brief to periods of IFR visibilities are
likely given upstream obs. When to end TS is other concern with
additional storms currently behind the front. Have left timing of
this rather similar at this point but will have to monitor trends.
Front should be south of the terminals before redevelopment
occurs in peak heating Monday.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...65








000
FXUS63 KTOP 312011
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
311 PM CDT Sun Aug 31 2014

.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014

Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.

Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.

Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.

Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.

.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014

For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.

Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.

Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1239 PM CDT SUN AUG 31 2014

Only minor changes to the forecasts. Will likely be an hour or two
of fairly persistent TS activity but feel a little better going with
TEMPO at this point and including some wind and further
visibility issues to deal with. Timing is become more certain but
still not completely confident.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...65







000
FXUS63 KTOP 312011
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
311 PM CDT Sun Aug 31 2014

.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014

Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.

Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.

Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.

Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.

.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014

For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.

Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.

Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1239 PM CDT SUN AUG 31 2014

Only minor changes to the forecasts. Will likely be an hour or two
of fairly persistent TS activity but feel a little better going with
TEMPO at this point and including some wind and further
visibility issues to deal with. Timing is become more certain but
still not completely confident.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...65








000
FXUS63 KTOP 311739
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1239 PM CDT Sun Aug 31 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 418 AM CDT SUN AUG 31 2014

--Large Scale Overview---------------
At 3 AM, surface low pressure was centered in north central SD with
a trailing cold front just entering extreme northwest Nebraska. A
modest low level jet was bringing a bit of low level moisture
advection into the central plains. A rather sharp short wave trough
axis was entering western Kansas while stronger short wave energy
and a jet of stronger mid-level westerlies was quickly moving into
Wyoming. Scattered thunderstorms had developed in western and north
central KS in advance of the incoming short wave trough and
isentropic ascent on the LLJ ahead of the trough axis.

--Through Early Afternoon------------
The area of scattered showers and embedded thunderstorms will track
east through the morning hours, likely decreasing in intensity and
coverage after 10 AM or so as the LLJ wanes. Instability is meager
and elevated within this airmass and no severe storms are expected
through early afternoon. As this initial trough axis moves over the
area, expect a period of a few hours of mid-level subsidence in its
wake. Some models suggest that this will aid in a decrease in
boundary layer dewpoints due to the combination of mixing and
subsidence. If this occurs, expect less in the way of afternoon
instability, although low-level moisture would still likely increase
late in the day in advance of the next trough. During this period,
the cold front will advance into central Nebraska and northwest
Kansas while new surface low pressure intensifies over western
Kansas. Temperatures will warm quickly as early clouds dissipate and
move east, with highs likely surging into the middle 90s.

--Mid Afternoon Through Tonight------
Expect thunderstorms to develop near the cold front in central
Nebraska initially, with activity probably increasing into the
locally backed flow ahead of the surface low in western Kansas by
late afternoon. This early activity should move to the northeast and
east, and should for the most part avoid the forecast area this
afternoon. However, this will depend on the cold front location by
mid afternoon, and could see a few of these storms develop into
north central KS as early 4 PM. The effective front will progress
southeast during the evening as the surface low moves into central
KS and the low level jet rapidly intensifies across the entire area.
Enhanced convergence in the frontal zone will result in widespread
thunderstorm development, eventually making its way into the local
forecast area. The southward progression of the front should slow
markedly in the local area during the early morning hours, which
will result in the northern half of the area having a very good
chance for thunderstorms while east central KS will be on the
edge...but will be likely to have storms as well. Even with the
front still in the area by sunrise, the upper wave and associated
thunderstorms should push off to the east by 12Z.

--Specific Hazards--------------------
The main uncertainty in the extent of various hazards lies in some
question of the dominant storm mode at any given time. Early on,
expect supercells and QLCS structure with embedded supercells. As
forcing along the front increases during the evening, expect storm
mode to transition into dominant QLCS or bowing segments with
embedded rotation. LCL heights early in the event are expected to be
rather high locally, so if storms are in the area during the
afternoon and early evening would expect the primary hazards to be
hail and wind...perhaps in combination. As the evening progresses,
the evolution of storm mode will likely begin to favor damaging
winds with embedded areas of hail. The sharply increasing low level
wind shear is likely to maintain a non-zero tornado threat through
the evening and perhaps into the early morning as 0-1 km helicity in
the 300-500 m2/s2 range will be common and LCLs will decrease with
time. Also expect the storms to remain surface based or near-surface
based well into the evening. So, this non-zero tornado threat will
need to be monitored throughout the event, although some recent
model guidance indicates that an increased potential for widespread
damaging winds may be prevalent. In addition, as the front slows its
progression, could see some back-building along the front or perhaps
a series of more than one progressive bow echoes in northeast KS.
Atmospheric moisture content is very high and some parts of northern
KS are a bit saturated so a mainly localized flash flood threat may
materialize later tonight.

.LONG TERM...(Monday through Saturday)
Issued at 418 AM CDT SUN AUG 31 2014

By Monday morning, a broad mid-level trough will be in place over
the Northern Plains with an area of low pressure slowly tracking
eastward over the region. The cold front that will be supporting
thunderstorm development tonight is expected to be very slow moving,
with most models showing this boundary stretching from central to
northeast Kansas by Monday morning and barely exiting east central
Kansas by Monday evening. Some of the thunderstorm activity from an
MCS that may develop overnight tonight near the Kansas/Nebraska
border may linger into the morning hours across far eastern Kansas.
While this scattered thunderstorm activity may diminish during the
morning and early afternoon hours, several models suggest a
redevelopment of storms along and ahead of the boundary across east
central Kansas as a passing embedded shortwave looks to provide
additional support for this storm development. Also, with this
expected brief break in precipitation through the day, it should be
enough to boost temperatures into the upper 80s/near 90 degrees
across east central Kansas, helping to increase the instability
across the region. Some of these storms may be strong to severe
during the afternoon and evening hours as 2000-3000J/kg of CAPE are
possible along with 40-60kts of 0-6km bulk shear. The primary
threats with the strongest storms will be large hail and damaging
winds. As the mid-level trough associated with this system lifts
toward the Great Lakes region, the mid-level flow will transition to
a more zonal pattern, and it should help to finally push the front
just south of the forecast area Monday night. Scattered showers and
thunderstorms should diminish from north to south Monday night into
Tuesday morning with this slight southward shift in the front.
However, models continue to trend toward having this front lift back
northward over the region as a warm front Tuesday night into Wednesday.
This boundary, with the support of a few weak embedded shortwaves,
should support additional isolated to scattered thunderstorm
development, however there is still model uncertainty with regards
to the coverage of this thunderstorm activity across the forecast
area. Temperatures should warm up quickly on Wednesday as the
precipitation clears out, with highs in the upper 80s to mid 90s.

By Wednesday morning, models show the next mid-level trough moving
into the Pacific Northwest. However, models become more inconsistent
with the development of this trough as it progresses into the
Northern Plains, with the GFS lifting much of the trough into Canada
while the ECMWF deepens the trough over the Rockies and Northern
Plains by the latter part of the week. This translates to model
discrepancies with how far north the mid-level ridge over the
southern U.S. will be able to extend into the Central Plains.
Additionally, while both models agree that this trough will help to
push an area of low pressure through the Central Plains, there are
notable differences in the timing of this next frontal passage. The
ECMWF is more progressive (due to its solution of a deepening
trough) and has the front moving through Thursday night into Friday,
while the GFS is slower and brings the front through Friday
afternoon into Saturday morning. As a result, there is plenty of
uncertainty in the forecast for the end of the week for
precipitation chances, temperatures, and winds. There is the
potential for more widespread showers and thunderstorms with this
late-week frontal passage, but it`s difficult to pin down the timing
of these precipitation chances at this time.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1239 PM CDT SUN AUG 31 2014

Only minor changes to the forecasts. Will likely be an hour or two
of fairly persistent TS activity but feel a little better going with
TEMPO at this point and including some wind and further
visibility issues to deal with. Timing is become more certain but
still not completely confident.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...65








000
FXUS63 KTOP 311739
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1239 PM CDT Sun Aug 31 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 418 AM CDT SUN AUG 31 2014

--Large Scale Overview---------------
At 3 AM, surface low pressure was centered in north central SD with
a trailing cold front just entering extreme northwest Nebraska. A
modest low level jet was bringing a bit of low level moisture
advection into the central plains. A rather sharp short wave trough
axis was entering western Kansas while stronger short wave energy
and a jet of stronger mid-level westerlies was quickly moving into
Wyoming. Scattered thunderstorms had developed in western and north
central KS in advance of the incoming short wave trough and
isentropic ascent on the LLJ ahead of the trough axis.

--Through Early Afternoon------------
The area of scattered showers and embedded thunderstorms will track
east through the morning hours, likely decreasing in intensity and
coverage after 10 AM or so as the LLJ wanes. Instability is meager
and elevated within this airmass and no severe storms are expected
through early afternoon. As this initial trough axis moves over the
area, expect a period of a few hours of mid-level subsidence in its
wake. Some models suggest that this will aid in a decrease in
boundary layer dewpoints due to the combination of mixing and
subsidence. If this occurs, expect less in the way of afternoon
instability, although low-level moisture would still likely increase
late in the day in advance of the next trough. During this period,
the cold front will advance into central Nebraska and northwest
Kansas while new surface low pressure intensifies over western
Kansas. Temperatures will warm quickly as early clouds dissipate and
move east, with highs likely surging into the middle 90s.

--Mid Afternoon Through Tonight------
Expect thunderstorms to develop near the cold front in central
Nebraska initially, with activity probably increasing into the
locally backed flow ahead of the surface low in western Kansas by
late afternoon. This early activity should move to the northeast and
east, and should for the most part avoid the forecast area this
afternoon. However, this will depend on the cold front location by
mid afternoon, and could see a few of these storms develop into
north central KS as early 4 PM. The effective front will progress
southeast during the evening as the surface low moves into central
KS and the low level jet rapidly intensifies across the entire area.
Enhanced convergence in the frontal zone will result in widespread
thunderstorm development, eventually making its way into the local
forecast area. The southward progression of the front should slow
markedly in the local area during the early morning hours, which
will result in the northern half of the area having a very good
chance for thunderstorms while east central KS will be on the
edge...but will be likely to have storms as well. Even with the
front still in the area by sunrise, the upper wave and associated
thunderstorms should push off to the east by 12Z.

--Specific Hazards--------------------
The main uncertainty in the extent of various hazards lies in some
question of the dominant storm mode at any given time. Early on,
expect supercells and QLCS structure with embedded supercells. As
forcing along the front increases during the evening, expect storm
mode to transition into dominant QLCS or bowing segments with
embedded rotation. LCL heights early in the event are expected to be
rather high locally, so if storms are in the area during the
afternoon and early evening would expect the primary hazards to be
hail and wind...perhaps in combination. As the evening progresses,
the evolution of storm mode will likely begin to favor damaging
winds with embedded areas of hail. The sharply increasing low level
wind shear is likely to maintain a non-zero tornado threat through
the evening and perhaps into the early morning as 0-1 km helicity in
the 300-500 m2/s2 range will be common and LCLs will decrease with
time. Also expect the storms to remain surface based or near-surface
based well into the evening. So, this non-zero tornado threat will
need to be monitored throughout the event, although some recent
model guidance indicates that an increased potential for widespread
damaging winds may be prevalent. In addition, as the front slows its
progression, could see some back-building along the front or perhaps
a series of more than one progressive bow echoes in northeast KS.
Atmospheric moisture content is very high and some parts of northern
KS are a bit saturated so a mainly localized flash flood threat may
materialize later tonight.

.LONG TERM...(Monday through Saturday)
Issued at 418 AM CDT SUN AUG 31 2014

By Monday morning, a broad mid-level trough will be in place over
the Northern Plains with an area of low pressure slowly tracking
eastward over the region. The cold front that will be supporting
thunderstorm development tonight is expected to be very slow moving,
with most models showing this boundary stretching from central to
northeast Kansas by Monday morning and barely exiting east central
Kansas by Monday evening. Some of the thunderstorm activity from an
MCS that may develop overnight tonight near the Kansas/Nebraska
border may linger into the morning hours across far eastern Kansas.
While this scattered thunderstorm activity may diminish during the
morning and early afternoon hours, several models suggest a
redevelopment of storms along and ahead of the boundary across east
central Kansas as a passing embedded shortwave looks to provide
additional support for this storm development. Also, with this
expected brief break in precipitation through the day, it should be
enough to boost temperatures into the upper 80s/near 90 degrees
across east central Kansas, helping to increase the instability
across the region. Some of these storms may be strong to severe
during the afternoon and evening hours as 2000-3000J/kg of CAPE are
possible along with 40-60kts of 0-6km bulk shear. The primary
threats with the strongest storms will be large hail and damaging
winds. As the mid-level trough associated with this system lifts
toward the Great Lakes region, the mid-level flow will transition to
a more zonal pattern, and it should help to finally push the front
just south of the forecast area Monday night. Scattered showers and
thunderstorms should diminish from north to south Monday night into
Tuesday morning with this slight southward shift in the front.
However, models continue to trend toward having this front lift back
northward over the region as a warm front Tuesday night into Wednesday.
This boundary, with the support of a few weak embedded shortwaves,
should support additional isolated to scattered thunderstorm
development, however there is still model uncertainty with regards
to the coverage of this thunderstorm activity across the forecast
area. Temperatures should warm up quickly on Wednesday as the
precipitation clears out, with highs in the upper 80s to mid 90s.

By Wednesday morning, models show the next mid-level trough moving
into the Pacific Northwest. However, models become more inconsistent
with the development of this trough as it progresses into the
Northern Plains, with the GFS lifting much of the trough into Canada
while the ECMWF deepens the trough over the Rockies and Northern
Plains by the latter part of the week. This translates to model
discrepancies with how far north the mid-level ridge over the
southern U.S. will be able to extend into the Central Plains.
Additionally, while both models agree that this trough will help to
push an area of low pressure through the Central Plains, there are
notable differences in the timing of this next frontal passage. The
ECMWF is more progressive (due to its solution of a deepening
trough) and has the front moving through Thursday night into Friday,
while the GFS is slower and brings the front through Friday
afternoon into Saturday morning. As a result, there is plenty of
uncertainty in the forecast for the end of the week for
precipitation chances, temperatures, and winds. There is the
potential for more widespread showers and thunderstorms with this
late-week frontal passage, but it`s difficult to pin down the timing
of these precipitation chances at this time.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1239 PM CDT SUN AUG 31 2014

Only minor changes to the forecasts. Will likely be an hour or two
of fairly persistent TS activity but feel a little better going with
TEMPO at this point and including some wind and further
visibility issues to deal with. Timing is become more certain but
still not completely confident.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...65







000
FXUS63 KTOP 311141
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
641 AM CDT Sun Aug 31 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 418 AM CDT SUN AUG 31 2014

--Large Scale Overview---------------
At 3 AM, surface low pressure was centered in north central SD with
a trailing cold front just entering extreme northwest Nebraska. A
modest low level jet was bringing a bit of low level moisture
advection into the central plains. A rather sharp short wave trough
axis was entering western Kansas while stronger short wave energy
and a jet of stronger mid-level westerlies was quickly moving into
Wyoming. Scattered thunderstorms had developed in western and north
central KS in advance of the incoming short wave trough and
isentropic ascent on the LLJ ahead of the trough axis.

--Through Early Afternoon------------
The area of scattered showers and embedded thunderstorms will track
east through the morning hours, likely decreasing in intensity and
coverage after 10 AM or so as the LLJ wanes. Instability is meager
and elevated within this airmass and no severe storms are expected
through early afternoon. As this initial trough axis moves over the
area, expect a period of a few hours of mid-level subsidence in its
wake. Some models suggest that this will aid in a decrease in
boundary layer dewpoints due to the combination of mixing and
subsidence. If this occurs, expect less in the way of afternoon
instability, although low-level moisture would still likely increase
late in the day in advance of the next trough. During this period,
the cold front will advance into central Nebraska and northwest
Kansas while new surface low pressure intensifies over western
Kansas. Temperatures will warm quickly as early clouds dissipate and
move east, with highs likely surging into the middle 90s.

--Mid Afternoon Through Tonight------
Expect thunderstorms to develop near the cold front in central
Nebraska initially, with activity probably increasing into the
locally backed flow ahead of the surface low in western Kansas by
late afternoon. This early activity should move to the northeast and
east, and should for the most part avoid the forecast area this
afternoon. However, this will depend on the cold front location by
mid afternoon, and could see a few of these storms develop into
north central KS as early 4 PM. The effective front will progress
southeast during the evening as the surface low moves into central
KS and the low level jet rapidly intensifies across the entire area.
Enhanced convergence in the frontal zone will result in widespread
thunderstorm development, eventually making its way into the local
forecast area. The southward progression of the front should slow
markedly in the local area during the early morning hours, which
will result in the northern half of the area having a very good
chance for thunderstorms while east central KS will be on the
edge...but will be likely to have storms as well. Even with the
front still in the area by sunrise, the upper wave and associated
thunderstorms should push off to the east by 12Z.

--Specific Hazards--------------------
The main uncertainty in the extent of various hazards lies in some
question of the dominant storm mode at any given time. Early on,
expect supercells and QLCS structure with embedded supercells. As
forcing along the front increases during the evening, expect storm
mode to transition into dominant QLCS or bowing segments with
embedded rotation. LCL heights early in the event are expected to be
rather high locally, so if storms are in the area during the
afternoon and early evening would expect the primary hazards to be
hail and wind...perhaps in combination. As the evening progresses,
the evolution of storm mode will likely begin to favor damaging
winds with embedded areas of hail. The sharply increasing low level
wind shear is likely to maintain a non-zero tornado threat through
the evening and perhaps into the early morning as 0-1 km helicity in
the 300-500 m2/s2 range will be common and LCLs will decrease with
time. Also expect the storms to remain surface based or near-surface
based well into the evening. So, this non-zero tornado threat will
need to be monitored throughout the event, although some recent
model guidance indicates that an increased potential for widespread
damaging winds may be prevalent. In addition, as the front slows its
progression, could see some back-building along the front or perhaps
a series of more than one progressive bow echoes in northeast KS.
Atmospheric moisture content is very high and some parts of northern
KS are a bit saturated so a mainly localized flash flood threat may
materialize later tonight.

.LONG TERM...(Monday through Saturday)
Issued at 418 AM CDT SUN AUG 31 2014

By Monday morning, a broad mid-level trough will be in place over
the Northern Plains with an area of low pressure slowly tracking
eastward over the region. The cold front that will be supporting
thunderstorm development tonight is expected to be very slow moving,
with most models showing this boundary stretching from central to
northeast Kansas by Monday morning and barely exiting east central
Kansas by Monday evening. Some of the thunderstorm activity from an
MCS that may develop overnight tonight near the Kansas/Nebraska
border may linger into the morning hours across far eastern Kansas.
While this scattered thunderstorm activity may diminish during the
morning and early afternoon hours, several models suggest a
redevelopment of storms along and ahead of the boundary across east
central Kansas as a passing embedded shortwave looks to provide
additional support for this storm development. Also, with this
expected brief break in precipitation through the day, it should be
enough to boost temperatures into the upper 80s/near 90 degrees
across east central Kansas, helping to increase the instability
across the region. Some of these storms may be strong to severe
during the afternoon and evening hours as 2000-3000J/kg of CAPE are
possible along with 40-60kts of 0-6km bulk shear. The primary
threats with the strongest storms will be large hail and damaging
winds. As the mid-level trough associated with this system lifts
toward the Great Lakes region, the mid-level flow will transition to
a more zonal pattern, and it should help to finally push the front
just south of the forecast area Monday night. Scattered showers and
thunderstorms should diminish from north to south Monday night into
Tuesday morning with this slight southward shift in the front.
However, models continue to trend toward having this front lift back
northward over the region as a warm front Tuesday night into Wednesday.
This boundary, with the support of a few weak embedded shortwaves,
should support additional isolated to scattered thunderstorm
development, however there is still model uncertainty with regards
to the coverage of this thunderstorm activity across the forecast
area. Temperatures should warm up quickly on Wednesday as the
precipitation clears out, with highs in the upper 80s to mid 90s.

By Wednesday morning, models show the next mid-level trough moving
into the Pacific Northwest. However, models become more inconsistent
with the development of this trough as it progresses into the
Northern Plains, with the GFS lifting much of the trough into Canada
while the ECMWF deepens the trough over the Rockies and Northern
Plains by the latter part of the week. This translates to model
discrepancies with how far north the mid-level ridge over the
southern U.S. will be able to extend into the Central Plains.
Additionally, while both models agree that this trough will help to
push an area of low pressure through the Central Plains, there are
notable differences in the timing of this next frontal passage. The
ECMWF is more progressive (due to its solution of a deepening
trough) and has the front moving through Thursday night into Friday,
while the GFS is slower and brings the front through Friday
afternoon into Saturday morning. As a result, there is plenty of
uncertainty in the forecast for the end of the week for
precipitation chances, temperatures, and winds. There is the
potential for more widespread showers and thunderstorms with this
late-week frontal passage, but it`s difficult to pin down the timing
of these precipitation chances at this time.

&&

.AVIATION...(For the 12Z TAFs through 12Z Monday Morning)
Issued at 635 AM CDT SUN AUG 31 2014

A round of scattered thunderstorms will likely impact MHK between
12Z and 16Z, with primarily VFR conditions likely even during TS.
These TS may make it as far east as TOP/FOE, but expect weakening
and they should dissipate as they move east. Will have gusty
south winds for much of the day/evening, but otherwise VFR until
strong thunderstorms impact TAF sites this evening into the early
morning. These TS may produce damaging winds as well as large
hail. Expect IFR conditions or worse during strongest storms but
with uncertainty in exact timing, have highlighted the general
time frame with MVFR vis.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...Barjenbruch







000
FXUS63 KTOP 311141
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
641 AM CDT Sun Aug 31 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 418 AM CDT SUN AUG 31 2014

--Large Scale Overview---------------
At 3 AM, surface low pressure was centered in north central SD with
a trailing cold front just entering extreme northwest Nebraska. A
modest low level jet was bringing a bit of low level moisture
advection into the central plains. A rather sharp short wave trough
axis was entering western Kansas while stronger short wave energy
and a jet of stronger mid-level westerlies was quickly moving into
Wyoming. Scattered thunderstorms had developed in western and north
central KS in advance of the incoming short wave trough and
isentropic ascent on the LLJ ahead of the trough axis.

--Through Early Afternoon------------
The area of scattered showers and embedded thunderstorms will track
east through the morning hours, likely decreasing in intensity and
coverage after 10 AM or so as the LLJ wanes. Instability is meager
and elevated within this airmass and no severe storms are expected
through early afternoon. As this initial trough axis moves over the
area, expect a period of a few hours of mid-level subsidence in its
wake. Some models suggest that this will aid in a decrease in
boundary layer dewpoints due to the combination of mixing and
subsidence. If this occurs, expect less in the way of afternoon
instability, although low-level moisture would still likely increase
late in the day in advance of the next trough. During this period,
the cold front will advance into central Nebraska and northwest
Kansas while new surface low pressure intensifies over western
Kansas. Temperatures will warm quickly as early clouds dissipate and
move east, with highs likely surging into the middle 90s.

--Mid Afternoon Through Tonight------
Expect thunderstorms to develop near the cold front in central
Nebraska initially, with activity probably increasing into the
locally backed flow ahead of the surface low in western Kansas by
late afternoon. This early activity should move to the northeast and
east, and should for the most part avoid the forecast area this
afternoon. However, this will depend on the cold front location by
mid afternoon, and could see a few of these storms develop into
north central KS as early 4 PM. The effective front will progress
southeast during the evening as the surface low moves into central
KS and the low level jet rapidly intensifies across the entire area.
Enhanced convergence in the frontal zone will result in widespread
thunderstorm development, eventually making its way into the local
forecast area. The southward progression of the front should slow
markedly in the local area during the early morning hours, which
will result in the northern half of the area having a very good
chance for thunderstorms while east central KS will be on the
edge...but will be likely to have storms as well. Even with the
front still in the area by sunrise, the upper wave and associated
thunderstorms should push off to the east by 12Z.

--Specific Hazards--------------------
The main uncertainty in the extent of various hazards lies in some
question of the dominant storm mode at any given time. Early on,
expect supercells and QLCS structure with embedded supercells. As
forcing along the front increases during the evening, expect storm
mode to transition into dominant QLCS or bowing segments with
embedded rotation. LCL heights early in the event are expected to be
rather high locally, so if storms are in the area during the
afternoon and early evening would expect the primary hazards to be
hail and wind...perhaps in combination. As the evening progresses,
the evolution of storm mode will likely begin to favor damaging
winds with embedded areas of hail. The sharply increasing low level
wind shear is likely to maintain a non-zero tornado threat through
the evening and perhaps into the early morning as 0-1 km helicity in
the 300-500 m2/s2 range will be common and LCLs will decrease with
time. Also expect the storms to remain surface based or near-surface
based well into the evening. So, this non-zero tornado threat will
need to be monitored throughout the event, although some recent
model guidance indicates that an increased potential for widespread
damaging winds may be prevalent. In addition, as the front slows its
progression, could see some back-building along the front or perhaps
a series of more than one progressive bow echoes in northeast KS.
Atmospheric moisture content is very high and some parts of northern
KS are a bit saturated so a mainly localized flash flood threat may
materialize later tonight.

.LONG TERM...(Monday through Saturday)
Issued at 418 AM CDT SUN AUG 31 2014

By Monday morning, a broad mid-level trough will be in place over
the Northern Plains with an area of low pressure slowly tracking
eastward over the region. The cold front that will be supporting
thunderstorm development tonight is expected to be very slow moving,
with most models showing this boundary stretching from central to
northeast Kansas by Monday morning and barely exiting east central
Kansas by Monday evening. Some of the thunderstorm activity from an
MCS that may develop overnight tonight near the Kansas/Nebraska
border may linger into the morning hours across far eastern Kansas.
While this scattered thunderstorm activity may diminish during the
morning and early afternoon hours, several models suggest a
redevelopment of storms along and ahead of the boundary across east
central Kansas as a passing embedded shortwave looks to provide
additional support for this storm development. Also, with this
expected brief break in precipitation through the day, it should be
enough to boost temperatures into the upper 80s/near 90 degrees
across east central Kansas, helping to increase the instability
across the region. Some of these storms may be strong to severe
during the afternoon and evening hours as 2000-3000J/kg of CAPE are
possible along with 40-60kts of 0-6km bulk shear. The primary
threats with the strongest storms will be large hail and damaging
winds. As the mid-level trough associated with this system lifts
toward the Great Lakes region, the mid-level flow will transition to
a more zonal pattern, and it should help to finally push the front
just south of the forecast area Monday night. Scattered showers and
thunderstorms should diminish from north to south Monday night into
Tuesday morning with this slight southward shift in the front.
However, models continue to trend toward having this front lift back
northward over the region as a warm front Tuesday night into Wednesday.
This boundary, with the support of a few weak embedded shortwaves,
should support additional isolated to scattered thunderstorm
development, however there is still model uncertainty with regards
to the coverage of this thunderstorm activity across the forecast
area. Temperatures should warm up quickly on Wednesday as the
precipitation clears out, with highs in the upper 80s to mid 90s.

By Wednesday morning, models show the next mid-level trough moving
into the Pacific Northwest. However, models become more inconsistent
with the development of this trough as it progresses into the
Northern Plains, with the GFS lifting much of the trough into Canada
while the ECMWF deepens the trough over the Rockies and Northern
Plains by the latter part of the week. This translates to model
discrepancies with how far north the mid-level ridge over the
southern U.S. will be able to extend into the Central Plains.
Additionally, while both models agree that this trough will help to
push an area of low pressure through the Central Plains, there are
notable differences in the timing of this next frontal passage. The
ECMWF is more progressive (due to its solution of a deepening
trough) and has the front moving through Thursday night into Friday,
while the GFS is slower and brings the front through Friday
afternoon into Saturday morning. As a result, there is plenty of
uncertainty in the forecast for the end of the week for
precipitation chances, temperatures, and winds. There is the
potential for more widespread showers and thunderstorms with this
late-week frontal passage, but it`s difficult to pin down the timing
of these precipitation chances at this time.

&&

.AVIATION...(For the 12Z TAFs through 12Z Monday Morning)
Issued at 635 AM CDT SUN AUG 31 2014

A round of scattered thunderstorms will likely impact MHK between
12Z and 16Z, with primarily VFR conditions likely even during TS.
These TS may make it as far east as TOP/FOE, but expect weakening
and they should dissipate as they move east. Will have gusty
south winds for much of the day/evening, but otherwise VFR until
strong thunderstorms impact TAF sites this evening into the early
morning. These TS may produce damaging winds as well as large
hail. Expect IFR conditions or worse during strongest storms but
with uncertainty in exact timing, have highlighted the general
time frame with MVFR vis.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...Barjenbruch








000
FXUS63 KTOP 310921
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
421 AM CDT Sun Aug 31 2014

.SHORT TERM...(Today and Tonight)
Issued at 418 AM CDT SUN AUG 31 2014

--Large Scale Overview---------------
At 3 AM, surface low pressure was centered in north central SD with
a trailing cold front just entering extreme northwest Nebraska. A
modest low level jet was bringing a bit of low level moisture
advection into the central plains. A rather sharp short wave trough
axis was entering western Kansas while stronger short wave energy
and a jet of stronger mid-level westerlies was quickly moving into
Wyoming. Scattered thunderstorms had developed in western and north
central KS in advance of the incoming short wave trough and
isentropic ascent on the LLJ ahead of the trough axis.

--Through Early Afternoon------------
The area of scattered showers and embedded thunderstorms will track
east through the morning hours, likely decreasing in intensity and
coverage after 10 AM or so as the LLJ wanes. Instability is meager
and elevated within this airmass and no severe storms are expected
through early afternoon. As this initial trough axis moves over the
area, expect a period of a few hours of mid-level subsidence in its
wake. Some models suggest that this will aid in a decrease in
boundary layer dewpoints due to the combination of mixing and
subsidence. If this occurs, expect less in the way of afternoon
instability, although low-level moisture would still likely increase
late in the day in advance of the next trough. During this period,
the cold front will advance into central Nebraska and northwest
Kansas while new surface low pressure intensifies over western
Kansas. Temperatures will warm quickly as early clouds dissipate and
move east, with highs likely surging into the middle 90s.

--Mid Afternoon Through Tonight------
Expect thunderstorms to develop near the cold front in central
Nebraska initially, with activity probably increasing into the
locally backed flow ahead of the surface low in western Kansas by
late afternoon. This early activity should move to the northeast and
east, and should for the most part avoid the forecast area this
afternoon. However, this will depend on the cold front location by
mid afternoon, and could see a few of these storms develop into
north central KS as early 4 PM. The effective front will progress
southeast during the evening as the surface low moves into central
KS and the low level jet rapidly intensifies across the entire area.
Enhanced convergence in the frontal zone will result in widespread
thunderstorm development, eventually making its way into the local
forecast area. The southward progression of the front should slow
markedly in the local area during the early morning hours, which
will result in the northern half of the area having a very good
chance for thunderstorms while east central KS will be on the
edge...but will be likely to have storms as well. Even with the
front still in the area by sunrise, the upper wave and associated
thunderstorms should push off to the east by 12Z.

--Specific Hazards--------------------
The main uncertainty in the extent of various hazards lies in some
question of the dominant storm mode at any given time. Early on,
expect supercells and QLCS structure with embedded supercells. As
forcing along the front increases during the evening, expect storm
mode to transition into dominant QLCS or bowing segments with
embedded rotation. LCL heights early in the event are expected to be
rather high locally, so if storms are in the area during the
afternoon and early evening would expect the primary hazards to be
hail and wind...perhaps in combination. As the evening progresses,
the evolution of storm mode will likely begin to favor damaging
winds with embedded areas of hail. The sharply increasing low level
wind shear is likely to maintain a non-zero tornado threat through
the evening and perhaps into the early morning as 0-1 km helicity in
the 300-500 m2/s2 range will be common and LCLs will decrease with
time. Also expect the storms to remain surface based or near-surface
based well into the evening. So, this non-zero tornado threat will
need to be monitored throughout the event, although some recent
model guidance indicates that an increased potential for widespread
damaging winds may be prevalent. In addition, as the front slows its
progression, could see some back-building along the front or perhaps
a series of more than one progressive bow echoes in northeast KS.
Atmospheric moisture content is very high and some parts of northern
KS are a bit saturated so a mainly localized flash flood threat may
materialize later tonight.


.LONG TERM...(Monday through Saturday)
Issued at 418 AM CDT SUN AUG 31 2014

By Monday morning, a broad mid-level trough will be in place over
the Northern Plains with an area of low pressure slowly tracking
eastward over the region. The cold front that will be supporting
thunderstorm development tonight is expected to be very slow moving,
with most models showing this boundary stretching from central to
northeast Kansas by Monday morning and barely exiting east central
Kansas by Monday evening. Some of the thunderstorm activity from an
MCS that may develop overnight tonight near the Kansas/Nebraska
border may linger into the morning hours across far eastern Kansas.
While this scattered thunderstorm activity may diminish during the
morning and early afternoon hours, several models suggest a
redevelopment of storms along and ahead of the boundary across east
central Kansas as a passing embedded shortwave looks to provide
additional support for this storm development. Also, with this
expected brief break in precipitation through the day, it should be
enough to boost temperatures into the upper 80s/near 90 degrees
across east central Kansas, helping to increase the instability
across the region. Some of these storms may be strong to severe
during the afternoon and evening hours as 2000-3000J/kg of CAPE are
possible along with 40-60kts of 0-6km bulk shear. The primary
threats with the strongest storms will be large hail and damaging
winds. As the mid-level trough associated with this system lifts
toward the Great Lakes region, the mid-level flow will transition to
a more zonal pattern, and it should help to finally push the front
just south of the forecast area Monday night. Scattered showers and
thunderstorms should diminish from north to south Monday night into
Tuesday morning with this slight southward shift in the front.
However, models continue to trend toward having this front lift back
northward over the region as a warm front Tuesday night into Wednesday.
This boundary, with the support of a few weak embedded shortwaves,
should support additional isolated to scattered thunderstorm
development, however there is still model uncertainty with regards
to the coverage of this thunderstorm activity across the forecast
area. Temperatures should warm up quickly on Wednesday as the
precipitation clears out, with highs in the upper 80s to mid 90s.

By Wednesday morning, models show the next mid-level trough moving
into the Pacific Northwest. However, models become more inconsistent
with the development of this trough as it progresses into the
Northern Plains, with the GFS lifting much of the trough into Canada
while the ECMWF deepens the trough over the Rockies and Northern
Plains by the latter part of the week. This translates to model
discrepancies with how far north the mid-level ridge over the
southern U.S. will be able to extend into the Central Plains.
Additionally, while both models agree that this trough will help to
push an area of low pressure through the Central Plains, there are
notable differences in the timing of this next frontal passage. The
ECMWF is more progressive (due to its solution of a deepening
trough) and has the front moving through Thursday night into Friday,
while the GFS is slower and brings the front through Friday
afternoon into Saturday morning. As a result, there is plenty of
uncertainty in the forecast for the end of the week for
precipitation chances, temperatures, and winds. There is the
potential for more widespread showers and thunderstorms with this
late-week frontal passage, but it`s difficult to pin down the timing
of these precipitation chances at this time.

&&

.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1135 PM CDT SAT AUG 30 2014

Expect VFR conditions through most of the next 24 hours. As the
low-level jet increases to 30 KTS there may be some moderate low-level
shear at the terminals from 9Z through 14Z SUN. Thunderstorm
chances will increase Sunday evening and have included VCTS.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...Gargan







000
FXUS63 KTOP 310921
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
421 AM CDT Sun Aug 31 2014

.SHORT TERM...(Today and Tonight)
Issued at 418 AM CDT SUN AUG 31 2014

--Large Scale Overview---------------
At 3 AM, surface low pressure was centered in north central SD with
a trailing cold front just entering extreme northwest Nebraska. A
modest low level jet was bringing a bit of low level moisture
advection into the central plains. A rather sharp short wave trough
axis was entering western Kansas while stronger short wave energy
and a jet of stronger mid-level westerlies was quickly moving into
Wyoming. Scattered thunderstorms had developed in western and north
central KS in advance of the incoming short wave trough and
isentropic ascent on the LLJ ahead of the trough axis.

--Through Early Afternoon------------
The area of scattered showers and embedded thunderstorms will track
east through the morning hours, likely decreasing in intensity and
coverage after 10 AM or so as the LLJ wanes. Instability is meager
and elevated within this airmass and no severe storms are expected
through early afternoon. As this initial trough axis moves over the
area, expect a period of a few hours of mid-level subsidence in its
wake. Some models suggest that this will aid in a decrease in
boundary layer dewpoints due to the combination of mixing and
subsidence. If this occurs, expect less in the way of afternoon
instability, although low-level moisture would still likely increase
late in the day in advance of the next trough. During this period,
the cold front will advance into central Nebraska and northwest
Kansas while new surface low pressure intensifies over western
Kansas. Temperatures will warm quickly as early clouds dissipate and
move east, with highs likely surging into the middle 90s.

--Mid Afternoon Through Tonight------
Expect thunderstorms to develop near the cold front in central
Nebraska initially, with activity probably increasing into the
locally backed flow ahead of the surface low in western Kansas by
late afternoon. This early activity should move to the northeast and
east, and should for the most part avoid the forecast area this
afternoon. However, this will depend on the cold front location by
mid afternoon, and could see a few of these storms develop into
north central KS as early 4 PM. The effective front will progress
southeast during the evening as the surface low moves into central
KS and the low level jet rapidly intensifies across the entire area.
Enhanced convergence in the frontal zone will result in widespread
thunderstorm development, eventually making its way into the local
forecast area. The southward progression of the front should slow
markedly in the local area during the early morning hours, which
will result in the northern half of the area having a very good
chance for thunderstorms while east central KS will be on the
edge...but will be likely to have storms as well. Even with the
front still in the area by sunrise, the upper wave and associated
thunderstorms should push off to the east by 12Z.

--Specific Hazards--------------------
The main uncertainty in the extent of various hazards lies in some
question of the dominant storm mode at any given time. Early on,
expect supercells and QLCS structure with embedded supercells. As
forcing along the front increases during the evening, expect storm
mode to transition into dominant QLCS or bowing segments with
embedded rotation. LCL heights early in the event are expected to be
rather high locally, so if storms are in the area during the
afternoon and early evening would expect the primary hazards to be
hail and wind...perhaps in combination. As the evening progresses,
the evolution of storm mode will likely begin to favor damaging
winds with embedded areas of hail. The sharply increasing low level
wind shear is likely to maintain a non-zero tornado threat through
the evening and perhaps into the early morning as 0-1 km helicity in
the 300-500 m2/s2 range will be common and LCLs will decrease with
time. Also expect the storms to remain surface based or near-surface
based well into the evening. So, this non-zero tornado threat will
need to be monitored throughout the event, although some recent
model guidance indicates that an increased potential for widespread
damaging winds may be prevalent. In addition, as the front slows its
progression, could see some back-building along the front or perhaps
a series of more than one progressive bow echoes in northeast KS.
Atmospheric moisture content is very high and some parts of northern
KS are a bit saturated so a mainly localized flash flood threat may
materialize later tonight.


.LONG TERM...(Monday through Saturday)
Issued at 418 AM CDT SUN AUG 31 2014

By Monday morning, a broad mid-level trough will be in place over
the Northern Plains with an area of low pressure slowly tracking
eastward over the region. The cold front that will be supporting
thunderstorm development tonight is expected to be very slow moving,
with most models showing this boundary stretching from central to
northeast Kansas by Monday morning and barely exiting east central
Kansas by Monday evening. Some of the thunderstorm activity from an
MCS that may develop overnight tonight near the Kansas/Nebraska
border may linger into the morning hours across far eastern Kansas.
While this scattered thunderstorm activity may diminish during the
morning and early afternoon hours, several models suggest a
redevelopment of storms along and ahead of the boundary across east
central Kansas as a passing embedded shortwave looks to provide
additional support for this storm development. Also, with this
expected brief break in precipitation through the day, it should be
enough to boost temperatures into the upper 80s/near 90 degrees
across east central Kansas, helping to increase the instability
across the region. Some of these storms may be strong to severe
during the afternoon and evening hours as 2000-3000J/kg of CAPE are
possible along with 40-60kts of 0-6km bulk shear. The primary
threats with the strongest storms will be large hail and damaging
winds. As the mid-level trough associated with this system lifts
toward the Great Lakes region, the mid-level flow will transition to
a more zonal pattern, and it should help to finally push the front
just south of the forecast area Monday night. Scattered showers and
thunderstorms should diminish from north to south Monday night into
Tuesday morning with this slight southward shift in the front.
However, models continue to trend toward having this front lift back
northward over the region as a warm front Tuesday night into Wednesday.
This boundary, with the support of a few weak embedded shortwaves,
should support additional isolated to scattered thunderstorm
development, however there is still model uncertainty with regards
to the coverage of this thunderstorm activity across the forecast
area. Temperatures should warm up quickly on Wednesday as the
precipitation clears out, with highs in the upper 80s to mid 90s.

By Wednesday morning, models show the next mid-level trough moving
into the Pacific Northwest. However, models become more inconsistent
with the development of this trough as it progresses into the
Northern Plains, with the GFS lifting much of the trough into Canada
while the ECMWF deepens the trough over the Rockies and Northern
Plains by the latter part of the week. This translates to model
discrepancies with how far north the mid-level ridge over the
southern U.S. will be able to extend into the Central Plains.
Additionally, while both models agree that this trough will help to
push an area of low pressure through the Central Plains, there are
notable differences in the timing of this next frontal passage. The
ECMWF is more progressive (due to its solution of a deepening
trough) and has the front moving through Thursday night into Friday,
while the GFS is slower and brings the front through Friday
afternoon into Saturday morning. As a result, there is plenty of
uncertainty in the forecast for the end of the week for
precipitation chances, temperatures, and winds. There is the
potential for more widespread showers and thunderstorms with this
late-week frontal passage, but it`s difficult to pin down the timing
of these precipitation chances at this time.

&&

.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1135 PM CDT SAT AUG 30 2014

Expect VFR conditions through most of the next 24 hours. As the
low-level jet increases to 30 KTS there may be some moderate low-level
shear at the terminals from 9Z through 14Z SUN. Thunderstorm
chances will increase Sunday evening and have included VCTS.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Hennecke
AVIATION...Gargan








000
FXUS63 KTOP 310439
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1139 PM CDT Sat Aug 30 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Sunday)
Issued at 311 PM CDT SAT AUG 30 2014

19Z water vapor imagery shows one shortwave trough moving into the
great lakes region with another upper level trough moving into the
northern Rockies. A lead shortwave within the western trough was
moving across NV and into UT with a second shortwave over the
pacific northwest coast. At the surface, there was relatively high
pressure over the forecast area with an ill defined frontal boundary
to the southeast and a surface low forming over WY. This has allowed
winds to remain light and variable this afternoon.

This afternoon and tonight should remain relatively quiet as forcing
from the initial shortwave out west looks to hold off until the early
morning Sunday. By Sunday morning, the models are hinting at the
possibility for some very high based showers and thunderstorms
moving into north central KS around sunrise. The 315K isentropic
surface shows rather deep upglide from about 800MB to nearly 600MB
across north central KS, but the airmass is pretty dry below 700MB.
Lapse rates above 600MB look to be nearly moist adiabatic so there
does not appear to be much elevated instability for a parcel lifted
from 700MB or above. This isentropic lift is progged to eventually
break down late in the morning as the lead shortwave passes east.
Otherwise models show a decent elevated mixed layer advecting into
central KS from the southwest through the day as 700MB temps warm to
between 12 and 14 C. Currently models show this capping inversion to
hold through the afternoon and models wait for the actual front to
move into the area for surface based convection to affect the
forecast area. Think this is plausible since the initial shortwave
moving into UT should pass through the area in the morning and the
better PVA and large scale forcing focusing north and west of the
forecast area through the afternoon. So in general think there may
be some high based precip move across north central KS in the
morning with the afternoon remaining generally dry. If an updraft
were to become especially vigorous in the morning, there could be a
localized damaging winds threat due to an inverted V profile below
700MB. Have trended POPs down during the afternoon and confine
chance POPs across far northwestern portions of the forecast area
for the late afternoon which should be in closer proximity to the
surface trough/front.

With some weak mixing overnight, think overnight lows will be in the
middle and upper 60s. Gradually increasing high clouds after
midnight should also help keep lows rather mild. The pressure
gradient really strengthens for Sunday with south winds likely
gusting over 30 MPH. Strong mixing of the boundary layer to around
825MB and decent insolation to go along with the warm air advection
is expected to lift afternoon temps into the middle and upper 90s
across the area.

.LONG TERM...(Sunday Night through Saturday)
Issued at 311 PM CDT SAT AUG 30 2014

Severe weather potential continues through at least the mid evening
hours, but have some questions on how the event will transpire. The
upstream front is not very well defined and with moisture pooling
into eastern Nebraska on easterly winds, could see quite an array of
convection developing here and along the front to the west in the
late day. If storms can maintain some separation, increasing low
level shear on a stout low level jet would produce supercells,
though even if such storms don`t occur until near/after sunset, LCL
heights look rather high for a significant tornado concern, so still
looking like primarily a wind and hail concern for severe weather,
with little in the way of a synoptic set-up for flooding.

Front/effective front still appears possible to be draped across
southern areas Labor Day. Depending on persistence and track of
overnight convection, could see moderate CAPE again develop along
with some decent speed shear for more severe weather potential. LCLs
are likely to be lower though low level shear at this point doesn`t
look very strong given modest wind fields. Models differ on how fast
return flow will develop, but at least a few periods of thunder
potential seem in order into at least Tuesday evening.

Flow pattern for the Central Plains becomes weaker with modest
ridging for the mid week for warming temps and a likely dry period
for most locations Wednesday into Thursday with highest well into the
90s. Guidance differs with the next cold front`s approach, stemming
from speed variations of the next shortwave trough`s passage across
the U.S./Canada border, with the 12Z ECMWF faster than its 0Z run
and the 12Z GFS. Forecast changes were minor at this point,
including adding small chances in the north Thursday night.
Thunderstorm chances then continue into the weekend with again the
front possibly becoming stationary over the area.

&&

.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1135 PM CDT SAT AUG 30 2014

Expect VFR conditions through most of the next 24 hours. As the
low-level jet increases to 30 KTS there may be some moderate low-level
shear at the terminals from 9Z through 14Z SUN. Thunderstorm
chances will increase Sunday evening and have included VCTS.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Wolters
LONG TERM...65
AVIATION...Gargan







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