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000
FXUS63 KLSX 222314
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
614 PM CDT Mon Sep 22 2014

.SHORT TERM: (Through Friday)
Issued at 252 PM CDT Mon Sep 22 2014

High pressure will result in excellent radiational cooling
tonight and have forecast temperatures in the middle to upper 40s.
The upper low now over Wyoming will stretch a trof across the
Plains through midweek with convection staying northwest of the
CWA due to dry and stable atmosphere overhead. The upper level
trof will gradually weaken or even retrograde with time keeping a
dry forecast intact. A gradual warming trend is expected the
remainder of the work week.

CVKING

.LONG TERM: (Saturday Through Next Monday)
Issued at 252 PM CDT Mon Sep 22 2014

Much of the CONUS will be covered by a very large upper level ridge
by next weekend thanks to the amplification/deepening of an
approaching upper level trof along the west coast late in the work
week. The suite of medium range models and their respective
ensembles are in relatively good agreement with this upper level
pattern and therefore confidence is higher than normal in dry and
tranquil conditions and slightly above normal temperatures in the
extended forecast.

CVKING

&&

.AVIATION:  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 608 PM CDT Mon Sep 22 2014

Specifics for KSTL, KCOU, KUIN, KCPS: Expect VFR conditions with
light winds due to a ridge of high pressure overhead.

Specifics for KSUS: Expect VFR conditions with light winds due to
a ridge of high pressure overhead. If steam fog develops along
the Missouri River, then the very light northeast/east winds which
are forecast overnight might push some of it onto the airport
grounds at KSUS. Confidence is too low at this time to include in
the TAF.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 222314
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
614 PM CDT Mon Sep 22 2014

.SHORT TERM: (Through Friday)
Issued at 252 PM CDT Mon Sep 22 2014

High pressure will result in excellent radiational cooling
tonight and have forecast temperatures in the middle to upper 40s.
The upper low now over Wyoming will stretch a trof across the
Plains through midweek with convection staying northwest of the
CWA due to dry and stable atmosphere overhead. The upper level
trof will gradually weaken or even retrograde with time keeping a
dry forecast intact. A gradual warming trend is expected the
remainder of the work week.

CVKING

.LONG TERM: (Saturday Through Next Monday)
Issued at 252 PM CDT Mon Sep 22 2014

Much of the CONUS will be covered by a very large upper level ridge
by next weekend thanks to the amplification/deepening of an
approaching upper level trof along the west coast late in the work
week. The suite of medium range models and their respective
ensembles are in relatively good agreement with this upper level
pattern and therefore confidence is higher than normal in dry and
tranquil conditions and slightly above normal temperatures in the
extended forecast.

CVKING

&&

.AVIATION:  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 608 PM CDT Mon Sep 22 2014

Specifics for KSTL, KCOU, KUIN, KCPS: Expect VFR conditions with
light winds due to a ridge of high pressure overhead.

Specifics for KSUS: Expect VFR conditions with light winds due to
a ridge of high pressure overhead. If steam fog develops along
the Missouri River, then the very light northeast/east winds which
are forecast overnight might push some of it onto the airport
grounds at KSUS. Confidence is too low at this time to include in
the TAF.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 221953
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
253 PM CDT Mon Sep 22 2014

.SHORT TERM: (Through Friday)
Issued at 252 PM CDT Mon Sep 22 2014

High pressure will result in excellent radiational cooling
tonight and have forecast temperatures in the middle to upper 40s.
The upper low now over Wyoming will stretch a trof across the
Plains through midweek with convection staying northwest of the
CWA due to dry and stable atmosphere overhead. The upper level
trof will gradually weaken or even retrograde with time keeping a
dry forecast in tact. A gradual warming trend is expected the
remainder of the work week.

CVKING

.LONG TERM: (Saturday Through Next Monday)
Issued at 252 PM CDT Mon Sep 22 2014

Much of the CONUS will be covered by a very large upper level ridge
by next weekend thanks to the amplification/deepening of an
approaching upper level trof along the west coast late in the work
week. The suite of medium range models and their respecitve
ensembles are in relatively good agreement with this upper level
pattern and therefore confidence is higher than normal in dry and
tranquil conditions and slightly above normal temperatures in the
extended forecast.

CVKING

&&

.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1239 PM CDT Mon Sep 22 2014

Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by midday on Tuesday, so winds to become southerly at KUIN and
KCOU and easterly over metro area.

Specifics for KSTL:
Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by 16z Tuesday, so winds to become easterly over metro area.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





000
FXUS63 KLSX 221953
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
253 PM CDT Mon Sep 22 2014

.SHORT TERM: (Through Friday)
Issued at 252 PM CDT Mon Sep 22 2014

High pressure will result in excellent radiational cooling
tonight and have forecast temperatures in the middle to upper 40s.
The upper low now over Wyoming will stretch a trof across the
Plains through midweek with convection staying northwest of the
CWA due to dry and stable atmosphere overhead. The upper level
trof will gradually weaken or even retrograde with time keeping a
dry forecast in tact. A gradual warming trend is expected the
remainder of the work week.

CVKING

.LONG TERM: (Saturday Through Next Monday)
Issued at 252 PM CDT Mon Sep 22 2014

Much of the CONUS will be covered by a very large upper level ridge
by next weekend thanks to the amplification/deepening of an
approaching upper level trof along the west coast late in the work
week. The suite of medium range models and their respecitve
ensembles are in relatively good agreement with this upper level
pattern and therefore confidence is higher than normal in dry and
tranquil conditions and slightly above normal temperatures in the
extended forecast.

CVKING

&&

.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1239 PM CDT Mon Sep 22 2014

Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by midday on Tuesday, so winds to become southerly at KUIN and
KCOU and easterly over metro area.

Specifics for KSTL:
Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by 16z Tuesday, so winds to become easterly over metro area.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX






000
FXUS63 KLSX 221740
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1240 PM CDT Mon Sep 22 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CDT Mon Sep 22 2014

The work week will start quiet and dry. An area of high pressure is
expected to move across the nthrn portion of the CWA today allowing
winds to become more E/SErly by this aftn. This will keep winds fairly
light and mixing heights around 900mb. Combine that mixing height
with 850mb temps rising to 10-12 degrees by 00z leads to max temps
in the mid/upper 60s. Add a few degrees on for a super adiabatic lapse
rate near the surface and highs should be near 70...and MOS guidance
supports those figures. Monday and Monday night will be the coolest
24 hr prd this week with a slow moderation in temps beginning on
Tuesday.

Miller

.LONG TERM:  (Tonight through Sunday)
Issued at 354 AM CDT Mon Sep 22 2014

Tranquil, dry weather pattern with a very gradual warming trend
beginning Tuesday.  Good radiational cooling tonight will lead to
slightly below normal low temperatures in the 40s. Upper low now
over southern Idaho will move out into the northern Plains with
some convection ahead of it spreading into northwest MO as early
as Tuesday or Tuesday night. It appears that the precipitation
will remain northwest of our forecast area due to dry and stable
atmosphere in the low-mid levels associated with the persistent
surface ridge extending from the Ohio Valley and northeast US west
southwest into eastern and southern MO. The upper level low will
weaken and likely begin to retrograde west southwestward through
the central Plains Thursday night and Friday. As the surface ridge
eventually weakens and a weak upper low comes up from the
southern Plains there may be a slight chance of showers/storms by
Sunday or Sunday night.

GKS
&&

.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1239 PM CDT Mon Sep 22 2014

Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by midday on Tuesday, so winds to become southerly at KUIN and
KCOU and easterly over metro area.

Specifics for KSTL:
Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by 16z Tuesday, so winds to become easterly over metro area.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$
WFO LSX






000
FXUS63 KLSX 221740
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1240 PM CDT Mon Sep 22 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CDT Mon Sep 22 2014

The work week will start quiet and dry. An area of high pressure is
expected to move across the nthrn portion of the CWA today allowing
winds to become more E/SErly by this aftn. This will keep winds fairly
light and mixing heights around 900mb. Combine that mixing height
with 850mb temps rising to 10-12 degrees by 00z leads to max temps
in the mid/upper 60s. Add a few degrees on for a super adiabatic lapse
rate near the surface and highs should be near 70...and MOS guidance
supports those figures. Monday and Monday night will be the coolest
24 hr prd this week with a slow moderation in temps beginning on
Tuesday.

Miller

.LONG TERM:  (Tonight through Sunday)
Issued at 354 AM CDT Mon Sep 22 2014

Tranquil, dry weather pattern with a very gradual warming trend
beginning Tuesday.  Good radiational cooling tonight will lead to
slightly below normal low temperatures in the 40s. Upper low now
over southern Idaho will move out into the northern Plains with
some convection ahead of it spreading into northwest MO as early
as Tuesday or Tuesday night. It appears that the precipitation
will remain northwest of our forecast area due to dry and stable
atmosphere in the low-mid levels associated with the persistent
surface ridge extending from the Ohio Valley and northeast US west
southwest into eastern and southern MO. The upper level low will
weaken and likely begin to retrograde west southwestward through
the central Plains Thursday night and Friday. As the surface ridge
eventually weakens and a weak upper low comes up from the
southern Plains there may be a slight chance of showers/storms by
Sunday or Sunday night.

GKS
&&

.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1239 PM CDT Mon Sep 22 2014

Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by midday on Tuesday, so winds to become southerly at KUIN and
KCOU and easterly over metro area.

Specifics for KSTL:
Ridge of high pressure to remain over the region with light and
variable winds and clear skies. Ridge will move off to the east a
bit by 16z Tuesday, so winds to become easterly over metro area.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$
WFO LSX







000
FXUS63 KLSX 221132
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
632 AM CDT Mon Sep 22 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CDT Mon Sep 22 2014

The work week will start quiet and dry. An area of high pressure is
expected to move across the nthrn portion of the CWA today allowing
winds to become more E/SErly by this aftn. This will keep winds fairly
light and mixing heights around 900mb. Combine that mixing height
with 850mb temps rising to 10-12 degrees by 00z leads to max temps
in the mid/upper 60s. Add a few degrees on for a super adiabatic lapse
rate near the surface and highs should be near 70...and MOS guidance
supports those figures. Monday and Monday night will be the coolest
24 hr prd this week with a slow moderation in temps beginning on
Tuesday.

Miller

.LONG TERM:  (Tonight through Sunday)
Issued at 354 AM CDT Mon Sep 22 2014

Tranquil, dry weather pattern with a very gradual warming trend
beginning Tuesday.  Good radiational cooling tonight will lead to
slightly below normal low temperatures in the 40s. Upper low now
over southern Idaho will move out into the northern Plains with
some convection ahead of it spreading into northwest MO as early
as Tuesday or Tuesday night. It appears that the precipitation
will remain northwest of our forecast area due to dry and stable
atmosphere in the low-mid levels associated with the persistent
surface ridge extending from the Ohio Valley and northeast US west
southwest into eastern and southern MO. The upper level low will
weaken and likely begin to retrograde west southwestward through
the central Plains Thursday night and Friday. As the surface ridge
eventually weakens and a weak upper low comes up from the
southern Plains there may be a slight chance of showers/storms by
Sunday or Sunday night.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 624 AM CDT Mon Sep 22 2014

High pressure in control providing clear skies and unrestricted
VSBYs. The only exception to that being a little river valley fog
that is affecting KCPS. KSUS also has a threat of fog but has yet
to be affected this mrng. Winds will remain lght/vrb thru the prd
going from nrly to SErly by this evening as the center of the sfc
ridge slides east.

Specifics for KSTL:

VFR thru the prd due to high pressure with winds aob 7kts.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 221132
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
632 AM CDT Mon Sep 22 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CDT Mon Sep 22 2014

The work week will start quiet and dry. An area of high pressure is
expected to move across the nthrn portion of the CWA today allowing
winds to become more E/SErly by this aftn. This will keep winds fairly
light and mixing heights around 900mb. Combine that mixing height
with 850mb temps rising to 10-12 degrees by 00z leads to max temps
in the mid/upper 60s. Add a few degrees on for a super adiabatic lapse
rate near the surface and highs should be near 70...and MOS guidance
supports those figures. Monday and Monday night will be the coolest
24 hr prd this week with a slow moderation in temps beginning on
Tuesday.

Miller

.LONG TERM:  (Tonight through Sunday)
Issued at 354 AM CDT Mon Sep 22 2014

Tranquil, dry weather pattern with a very gradual warming trend
beginning Tuesday.  Good radiational cooling tonight will lead to
slightly below normal low temperatures in the 40s. Upper low now
over southern Idaho will move out into the northern Plains with
some convection ahead of it spreading into northwest MO as early
as Tuesday or Tuesday night. It appears that the precipitation
will remain northwest of our forecast area due to dry and stable
atmosphere in the low-mid levels associated with the persistent
surface ridge extending from the Ohio Valley and northeast US west
southwest into eastern and southern MO. The upper level low will
weaken and likely begin to retrograde west southwestward through
the central Plains Thursday night and Friday. As the surface ridge
eventually weakens and a weak upper low comes up from the
southern Plains there may be a slight chance of showers/storms by
Sunday or Sunday night.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 624 AM CDT Mon Sep 22 2014

High pressure in control providing clear skies and unrestricted
VSBYs. The only exception to that being a little river valley fog
that is affecting KCPS. KSUS also has a threat of fog but has yet
to be affected this mrng. Winds will remain lght/vrb thru the prd
going from nrly to SErly by this evening as the center of the sfc
ridge slides east.

Specifics for KSTL:

VFR thru the prd due to high pressure with winds aob 7kts.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 220902
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
402 AM CDT Mon Sep 22 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CDT Mon Sep 22 2014

The work week will start quiet and dry. An area of high pressure is
expected to move across the nthrn portion of the CWA today allowing
winds to become more E/SErly by this aftn. This will keep winds fairly
light and mixing heights around 900mb. Combine that mixing height
with 850mb temps rising to 10-12 degrees by 00z leads to max temps
in the mid/upper 60s. Add a few degrees on for a superadiabatic lapse
rate near the surface and highs should be near 70...and MOS guidance
supports those figures. Monday and Monday night will be the coolest
24 hr prd this week with a slow moderation in temps beginning on
Tuesday.

Miller

.LONG TERM:  (Tonight through Sunday)
Issued at 354 AM CDT Mon Sep 22 2014

Tranquil, dry weather pattern with a very gradual warming trend
beginning Tuesday.  Good radiational cooling tonight will lead to
slightly below normal low temperatures in the 40s. Upper low now
over southern Idaho will move out into the northern Plains with
some convection ahead of it spreading into northwest MO as early
as Tuesday or Tuesday night. It appears that the precipitation
will remain northwest of our forecast area due to dry and stable
atmosphere in the low-mid levels associated with the persistent
surface ridge extending from the Ohio Valley and northeast US west
southwest into eastern and southern MO. The upper level low will
weaken and likely begin to retrograde west southwestward through
the central Plains Thursday night and Friday. As the surface ridge
eventually weakens and a weak upper low comes up from the
southern Plains there may be a slight chance of showers/storms by
Sunday or Sunday night.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Monday Night)
Issued at 1140 PM CDT Sun Sep 21 2014

A ridge of high pressure is building into the region, which will
ensure VFR conditions at all TAF sites except for KSUS, which
might be affected by steam fog between 09-12z. Northerly winds
will gradually veer through the period with wind speeds remaining
AOB 10 kts.

Specifics for KSTL: VFR with northerly winds veering to become
easterly towards the end of the 30-hr TAF period.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 220445
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1145 PM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 138 PM CDT Sun Sep 21 2014

Focus tonight will be temps. Sfc ridge builds into the region with
winds diminishing with sunset. Current cloud deck over nrn IL and
ern IA shud continue to break up this afternoon as it moves ese
leaving much of tonight clear. Greater mixing has occurred today
than prev anticipated, lowering dewpoints. While tonight is not a
great setup for radiational cooling as winds may stay up around 5
kts, believe CAA will help compensate. Have therefore trended aob
the coolest guidance for tonight.

.LONG TERM:  (Monday through Next Sunday)
Issued at 307 PM CDT Sun Sep 21 2014

High pressure will dominate over the region this week, allowing for
cool temperatures, dry conditions, and mostly clear skies through
early next weekend. Monday and Monday night, given the proximity of
the surface ridge axis and 850mb temps in the 8-10C range, should
yield the coolest temperatures this week, with highs Monday in the
low 70s, and lows Monday night in the 40s,to around 50 degrees in
the St. Louis metropolitan area. By Tuesday, south/southeast flow
will return to the area and slow warming trend will get underway.
Temperatures are expected to gradually warm, rebounding to the upper
70s to around 80 degrees area- wide by Friday.

Precipitation chances look to remain quite low through the
extended, though there are two disturbances in question that could
potentially impact the area. The first disturbance, a low pressure
system that is currently over far western Nevada per water vapor
imagery, is progged to become absorbed into the mean flow by
midweek. However, models are in agreement indicating an axis
through the Plains where the ridge will be weakened due to this
feature, which could be a focus for precipitation through the end
of the week. Currently, it looks like any precipitation that would
be associated with this feature would remain well to the west of
the CWFA prior to high pressure once again building over the
nation`s midsection. The GFS is also indicating another
disturbance for the late Saturday night/early Sunday time frame
which could potentially impact far southeast portions of the CWFA,
but it is too early to tell how this could potentially pan out.
Thus, have maintained a dry forecast.

Phillipson

&&

.AVIATION:  (For the 06z TAFs through 06z Monday Night)
Issued at 1140 PM CDT Sun Sep 21 2014

A ridge of high pressure is building into the region, which will
ensure VFR conditions at all TAF sites except for KSUS, which
might be affected by steam fog between 09-12z. Northerly winds
will gradually veer through the period with wind speeds remaining
AOB 10 kts.

Specifics for KSTL: VFR with northerly winds veering to become
easterly towards the end of the 30-hr TAF period.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 212228
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
528 PM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 138 PM CDT Sun Sep 21 2014

Focus tonight will be temps. Sfc ridge builds into the region with
winds diminishing with sunset. Current cloud deck over nrn IL and
ern IA shud continue to break up this afternoon as it moves ese
leaving much of tonight clear. Greater mixing has occurred today
than prev anticipated, lowering dewpoints. While tonight is not a
great setup for radiational cooling as winds may stay up around 5
kts, believe CAA will help compensate. Have therefore trended aob
the coolest guidance for tonight.

.LONG TERM:  (Monday through Next Sunday)
Issued at 307 PM CDT Sun Sep 21 2014

High pressure will dominate over the region this week, allowing for
cool temperatures, dry conditions, and mostly clear skies through
early next weekend. Monday and Monday night, given the proximity of
the surface ridge axis and 850mb temps in the 8-10C range, should
yield the coolest temperatures this week, with highs Monday in the
low 70s, and lows Monday night in the 40s,to around 50 degrees in
the St. Louis metropolitan area. By Tuesday, south/southeast flow
will return to the area and slow warming trend will get underway.
Temperatures are expected to gradually warm, rebounding to the upper
70s to around 80 degrees area- wide by Friday.

Precipitation chances look to remain quite low through the
extended, though there are two disturbances in question that could
potentially impact the area. The first disturbance, a low pressure
system that is currently over far western Nevada per water vapor
imagery, is progged to become absorbed into the mean flow by
midweek. However, models are in agreement indicating an axis
through the Plains where the ridge will be weakened due to this
feature, which could be a focus for precipitation through the end
of the week. Currently, it looks like any precipitation that would
be associated with this feature would remain well to the west of
the CWFA prior to high pressure once again building over the
nation`s midsection. The GFS is also indicating another
disturbance for the late Saturday night/early Sunday time frame
which could potentially impact far southeast portions of the CWFA,
but it is too early to tell how this could potentially pan out.
Thus, have maintained a dry forecast.

Phillipson

&&

.AVIATION:  (For the 00z TAFs through 00z Monday Evening)
Issued at 523 PM CDT Sun Sep 21 2014

VFR through the period, except in river valleys where steam fog is
possible overnight due to the difference between the warmer river
waters and the rapidly cooling air. Gusty north to northwest winds
will subside this evening with the loss of diurnal mixing. Expect
winds to gradually veer through the period as a high pressure
center moves into the region.

Specifics for KSTL: VFR through the period. Gusty north to
northwest winds will subside this evening with the loss of diurnal
mixing. Winds will gradually veer through the period as a high
pressure center moves into the region.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 212228
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
528 PM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 138 PM CDT Sun Sep 21 2014

Focus tonight will be temps. Sfc ridge builds into the region with
winds diminishing with sunset. Current cloud deck over nrn IL and
ern IA shud continue to break up this afternoon as it moves ese
leaving much of tonight clear. Greater mixing has occurred today
than prev anticipated, lowering dewpoints. While tonight is not a
great setup for radiational cooling as winds may stay up around 5
kts, believe CAA will help compensate. Have therefore trended aob
the coolest guidance for tonight.

.LONG TERM:  (Monday through Next Sunday)
Issued at 307 PM CDT Sun Sep 21 2014

High pressure will dominate over the region this week, allowing for
cool temperatures, dry conditions, and mostly clear skies through
early next weekend. Monday and Monday night, given the proximity of
the surface ridge axis and 850mb temps in the 8-10C range, should
yield the coolest temperatures this week, with highs Monday in the
low 70s, and lows Monday night in the 40s,to around 50 degrees in
the St. Louis metropolitan area. By Tuesday, south/southeast flow
will return to the area and slow warming trend will get underway.
Temperatures are expected to gradually warm, rebounding to the upper
70s to around 80 degrees area- wide by Friday.

Precipitation chances look to remain quite low through the
extended, though there are two disturbances in question that could
potentially impact the area. The first disturbance, a low pressure
system that is currently over far western Nevada per water vapor
imagery, is progged to become absorbed into the mean flow by
midweek. However, models are in agreement indicating an axis
through the Plains where the ridge will be weakened due to this
feature, which could be a focus for precipitation through the end
of the week. Currently, it looks like any precipitation that would
be associated with this feature would remain well to the west of
the CWFA prior to high pressure once again building over the
nation`s midsection. The GFS is also indicating another
disturbance for the late Saturday night/early Sunday time frame
which could potentially impact far southeast portions of the CWFA,
but it is too early to tell how this could potentially pan out.
Thus, have maintained a dry forecast.

Phillipson

&&

.AVIATION:  (For the 00z TAFs through 00z Monday Evening)
Issued at 523 PM CDT Sun Sep 21 2014

VFR through the period, except in river valleys where steam fog is
possible overnight due to the difference between the warmer river
waters and the rapidly cooling air. Gusty north to northwest winds
will subside this evening with the loss of diurnal mixing. Expect
winds to gradually veer through the period as a high pressure
center moves into the region.

Specifics for KSTL: VFR through the period. Gusty north to
northwest winds will subside this evening with the loss of diurnal
mixing. Winds will gradually veer through the period as a high
pressure center moves into the region.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 212010
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
310 PM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 138 PM CDT Sun Sep 21 2014

Focus tonight will be temps. Sfc ridge builds into the region with
winds diminishing with sunset. Current cloud deck over nrn IL and
ern IA shud continue to break up this afternoon as it moves ese
leaving much of tonight clear. Greater mixing has occurred today
than prev anticipated, lowering dewpoints. While tonight is not a
great setup for radiational cooling as winds may stay up around 5
kts, believe CAA will help compensate. Have therefore trended aob
the coolest guidance for tonight.

.LONG TERM:  (Monday through Next Sunday)
Issued at 307 PM CDT Sun Sep 21 2014

High pressure will dominate over the region this week, allowing for
cool temperatures, dry conditions, and mostly clear skies through
early next weekend. Monday and Monday night, given the proximity of
the surface ridge axis and 850mb temps in the 8-10C range, should
yield the coolest temperatures this week, with highs Monday in the
low 70s, and lows Monday night in the 40s,to around 50 degrees in
the St. Louis metropolitan area. By Tuesday, south/southeast flow
will return to the area and slow warming trend will get underway.
Temperatures are expected to gradually warm, rebounding to the upper
70s to around 80 degrees area- wide by Friday.

Precipitation chances look to remain quite low through the
extended, though there are two disturbances in question that could
potentially impact the area. The first disturbance, a low pressure
system that is currently over far western Nevada per water vapor
imagery, is progged to become absorbed into the mean flow by
midweek. However, models are in agreement indicating an axis
through the Plains where the ridge will be weakened due to this
feature, which could be a focus for precipitation through the end
of the week. Currently, it looks like any precipitation that would
be associated with this feature would remain well to the west of
the CWFA prior to high pressure once again building over the
nation`s midsection. The GFS is also indicating another
disturbance for the late Saturday night/early Sunday time frame
which could potentially impact far southeast portions of the CWFA,
but it is too early to tell how this could potentially pan out.
Thus, have maintained a dry forecast.

Phillipson

&&

.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1155 AM CDT Sun Sep 21 2014

Nwly winds will gust to around 20 kts this afternoon and diminish
with sunset remaining aob 5 kts. Steam FG is possible at SUS/CPS,
but how much it will impact terminal is uncertain attm. Winds will
become nly on Mon aob 5 kts.

Specifics for KSTL: VFR and dry thru the period. Gusty nw winds
will diminish and remain aob 5 kts overnight. Winds will become
nly Mon morning around 5 kts.

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     52  73  51  75 /   0   0   0   0
Quincy          46  70  47  71 /   0   0   0   0
Columbia        50  72  49  74 /   0   0   0   0
Jefferson City  49  72  48  74 /   0   0   0   0
Salem           47  69  46  72 /   0   0   0   0
Farmington      50  70  46  72 /   0   0   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 212010
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
310 PM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 138 PM CDT Sun Sep 21 2014

Focus tonight will be temps. Sfc ridge builds into the region with
winds diminishing with sunset. Current cloud deck over nrn IL and
ern IA shud continue to break up this afternoon as it moves ese
leaving much of tonight clear. Greater mixing has occurred today
than prev anticipated, lowering dewpoints. While tonight is not a
great setup for radiational cooling as winds may stay up around 5
kts, believe CAA will help compensate. Have therefore trended aob
the coolest guidance for tonight.

.LONG TERM:  (Monday through Next Sunday)
Issued at 307 PM CDT Sun Sep 21 2014

High pressure will dominate over the region this week, allowing for
cool temperatures, dry conditions, and mostly clear skies through
early next weekend. Monday and Monday night, given the proximity of
the surface ridge axis and 850mb temps in the 8-10C range, should
yield the coolest temperatures this week, with highs Monday in the
low 70s, and lows Monday night in the 40s,to around 50 degrees in
the St. Louis metropolitan area. By Tuesday, south/southeast flow
will return to the area and slow warming trend will get underway.
Temperatures are expected to gradually warm, rebounding to the upper
70s to around 80 degrees area- wide by Friday.

Precipitation chances look to remain quite low through the
extended, though there are two disturbances in question that could
potentially impact the area. The first disturbance, a low pressure
system that is currently over far western Nevada per water vapor
imagery, is progged to become absorbed into the mean flow by
midweek. However, models are in agreement indicating an axis
through the Plains where the ridge will be weakened due to this
feature, which could be a focus for precipitation through the end
of the week. Currently, it looks like any precipitation that would
be associated with this feature would remain well to the west of
the CWFA prior to high pressure once again building over the
nation`s midsection. The GFS is also indicating another
disturbance for the late Saturday night/early Sunday time frame
which could potentially impact far southeast portions of the CWFA,
but it is too early to tell how this could potentially pan out.
Thus, have maintained a dry forecast.

Phillipson

&&

.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1155 AM CDT Sun Sep 21 2014

Nwly winds will gust to around 20 kts this afternoon and diminish
with sunset remaining aob 5 kts. Steam FG is possible at SUS/CPS,
but how much it will impact terminal is uncertain attm. Winds will
become nly on Mon aob 5 kts.

Specifics for KSTL: VFR and dry thru the period. Gusty nw winds
will diminish and remain aob 5 kts overnight. Winds will become
nly Mon morning around 5 kts.

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     52  73  51  75 /   0   0   0   0
Quincy          46  70  47  71 /   0   0   0   0
Columbia        50  72  49  74 /   0   0   0   0
Jefferson City  49  72  48  74 /   0   0   0   0
Salem           47  69  46  72 /   0   0   0   0
Farmington      50  70  46  72 /   0   0   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 211839
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
139 PM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 138 PM CDT Sun Sep 21 2014

Focus tonight will be temps. Sfc ridge builds into the region with
winds diminishing with sunset. Current cloud deck over nrn IL and
ern IA shud continue to break up this afternoon as it moves ese
leaving much of tonight clear. Greater mixing has occurred today
than prev anticipated, lowering dewpoints. While tonight is not a
great setup for radiational cooling as winds may stay up around 5
kts, believe CAA will help compensate. Have therefore trended aob
the coolest guidance for tonight.


.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1155 AM CDT Sun Sep 21 2014

Nwly winds will gust to around 20 kts this afternoon and diminish
with sunset remaining aob 5 kts. Steam FG is possible at SUS/CPS,
but how much it will impact terminal is uncertain attm. Winds will
become nly on Mon aob 5 kts.

Specifics for KSTL: VFR and dry thru the period. Gusty nw winds
will diminish and remain aob 5 kts overnight. Winds will become
nly Mon morning around 5 kts.

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     79  52  73  52 /  10   0   0   0
Quincy          73  46  70  48 /  10   0   0   0
Columbia        77  50  72  50 /   0   0   0   0
Jefferson City  79  49  72  49 /   5   0   0   0
Salem           78  47  69  47 /  10   0   0   0
Farmington      76  50  70  47 /  10   0   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 211706
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1206 PM CDT Sun Sep 21 2014

.SHORT TERM: (Through Today)
Issued at 1116 PM CDT Sat Sep 20 2014

Convection along the prefrontal trough/wind shift has been pretty meager
this evng into the overnight hrs with most of the activity remaining
in our IL counties. Cold front has been slower...as advertised from
last night...not reaching the nthrn counties until close to 6Z. At this
rate the bndry should exit the sthrn zones between 10-12Z...taking any
threat for lingering -SHRAs with it. a strong short wave will pass just
to the NE of the CWA later today. Due to limited moisture, should only
see an slight increase in clouds...mainly across our IL counties. At
the SFC, cooler and drier air assoc with high pressure building into
the region from the nthrn Plains will cause high temps to be some 5-10
degrees cooler than yesterday. Winds may gust 20-25 mph for awhile this
aftn as decent CAA drops 850 temps to the upper single digits by 00Z.

2%

.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1155 AM CDT Sun Sep 21 2014

Nwly winds will gust to around 20 kts this afternoon and diminish
with sunset remaining aob 5 kts. Steam FG is possible at SUS/CPS,
but how much it will impact terminal is uncertain attm. Winds will
become nly on Mon aob 5 kts.

Specifics for KSTL: VFR and dry thru the period. Gusty nw winds
will diminish and remain aob 5 kts overnight. Winds will become
nly Mon morning around 5 kts.

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 211706
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1206 PM CDT Sun Sep 21 2014

.SHORT TERM: (Through Today)
Issued at 1116 PM CDT Sat Sep 20 2014

Convection along the prefrontal trough/wind shift has been pretty meager
this evng into the overnight hrs with most of the activity remaining
in our IL counties. Cold front has been slower...as advertised from
last night...not reaching the nthrn counties until close to 6Z. At this
rate the bndry should exit the sthrn zones between 10-12Z...taking any
threat for lingering -SHRAs with it. a strong short wave will pass just
to the NE of the CWA later today. Due to limited moisture, should only
see an slight increase in clouds...mainly across our IL counties. At
the SFC, cooler and drier air assoc with high pressure building into
the region from the nthrn Plains will cause high temps to be some 5-10
degrees cooler than yesterday. Winds may gust 20-25 mph for awhile this
aftn as decent CAA drops 850 temps to the upper single digits by 00Z.

2%

.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1155 AM CDT Sun Sep 21 2014

Nwly winds will gust to around 20 kts this afternoon and diminish
with sunset remaining aob 5 kts. Steam FG is possible at SUS/CPS,
but how much it will impact terminal is uncertain attm. Winds will
become nly on Mon aob 5 kts.

Specifics for KSTL: VFR and dry thru the period. Gusty nw winds
will diminish and remain aob 5 kts overnight. Winds will become
nly Mon morning around 5 kts.

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 211114
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
614 AM CDT Sun Sep 21 2014

.SHORT TERM: (Through Today)
Issued at 1116 PM CDT Sat Sep 20 2014

Convection along the prefrontal trough/wind shift has been pretty meager
this evng into the overnight hrs with most of the activity remaining
in our IL counties. Cold front has been slower...as advertised from
last night...not reaching the nthrn counties until close to 6Z. At this
rate the bndry should exit the sthrn zones between 10-12Z...taking any
threat for lingering -SHRAs with it. a strong short wave will pass just
to the NE of the CWA later today. Due to limited moisture, should only
see an slight increase in clouds...mainly across our IL counties. At
the SFC, cooler and drier air assoc with high pressure building into
the region from the nthrn Plains will cause high temps to be some 5-10
degrees cooler than yesterday. Winds may gust 20-25 mph for awhile this
aftn as decent CAA drops 850 temps to the upper single digits by 00Z.

2%

.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 12z TAFs through 12z Monday Morning)
Issued at 548 AM CDT Sun Sep 21 2014

Cold front has pushed south of the taf sites early this morning
as well as the showers/storms and most of the clouds. There will
be few-sct diurnal cumulus clouds late this morning and this
afternoon, especially in UIN. Gusty nwly surface winds today as the
surface ridge over the northern Plains builds southeastward into
MO behind the cold front. These surface winds will diminish this
evening with river valley fog possible late tonight which may
impact SUS and CPS.

Specifics for KSTL: Few diurnal cumulus clouds can be expected
late this morning and this afternoon. Nwly surface winds will be
gusty today, then diminish tonight as the surface high shifts
southeast into northwestern MO.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 211114
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
614 AM CDT Sun Sep 21 2014

.SHORT TERM: (Through Today)
Issued at 1116 PM CDT Sat Sep 20 2014

Convection along the prefrontal trough/wind shift has been pretty meager
this evng into the overnight hrs with most of the activity remaining
in our IL counties. Cold front has been slower...as advertised from
last night...not reaching the nthrn counties until close to 6Z. At this
rate the bndry should exit the sthrn zones between 10-12Z...taking any
threat for lingering -SHRAs with it. a strong short wave will pass just
to the NE of the CWA later today. Due to limited moisture, should only
see an slight increase in clouds...mainly across our IL counties. At
the SFC, cooler and drier air assoc with high pressure building into
the region from the nthrn Plains will cause high temps to be some 5-10
degrees cooler than yesterday. Winds may gust 20-25 mph for awhile this
aftn as decent CAA drops 850 temps to the upper single digits by 00Z.

2%

.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 12z TAFs through 12z Monday Morning)
Issued at 548 AM CDT Sun Sep 21 2014

Cold front has pushed south of the taf sites early this morning
as well as the showers/storms and most of the clouds. There will
be few-sct diurnal cumulus clouds late this morning and this
afternoon, especially in UIN. Gusty nwly surface winds today as the
surface ridge over the northern Plains builds southeastward into
MO behind the cold front. These surface winds will diminish this
evening with river valley fog possible late tonight which may
impact SUS and CPS.

Specifics for KSTL: Few diurnal cumulus clouds can be expected
late this morning and this afternoon. Nwly surface winds will be
gusty today, then diminish tonight as the surface high shifts
southeast into northwestern MO.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 210752
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
252 AM CDT Sun Sep 21 2014

.SHORT TERM: (Through Today)
Issued at 1116 PM CDT Sat Sep 20 2014

Convection along the prefrontal trough/wind shift has been pretty meager
this evng into the overnight hrs with most of the activity remaining
in our IL counties. Cold front has been slower...as advertised from
last night...not reaching the nthrn counties until close to 6Z. At this
rate the bndry should exit the sthrn zones between 10-12Z...taking any
threat for lingering -SHRAs with it. a strong short wave will pass just
to the NE of the CWA later today. Due to limited moisture, should only
see an slight increase in clouds...mainly across our IL counties. At
the SFC, cooler and drier air assoc with high pressure building into
the region from the nthrn Plains will cause high temps to be some 5-10
degrees cooler than yesterday. Winds may gust 20-25 mph for awhile this
aftn as decent CAA drops 850 temps to the upper single digits by 00Z.

2%

.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 633 PM CDT Sat Sep 20 2014

Scattered thunderstorms are possible this evening ahead of an
approaching cold front, but coverage is expected to be limited.
Winds will become northwesterly after fropa and gust to around 20
kts tomorrow. Generally VFR conditions are expected outside of
thunderstorms.

42

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





000
FXUS63 KLSX 210752
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
252 AM CDT Sun Sep 21 2014

.SHORT TERM: (Through Today)
Issued at 1116 PM CDT Sat Sep 20 2014

Convection along the prefrontal trough/wind shift has been pretty meager
this evng into the overnight hrs with most of the activity remaining
in our IL counties. Cold front has been slower...as advertised from
last night...not reaching the nthrn counties until close to 6Z. At this
rate the bndry should exit the sthrn zones between 10-12Z...taking any
threat for lingering -SHRAs with it. a strong short wave will pass just
to the NE of the CWA later today. Due to limited moisture, should only
see an slight increase in clouds...mainly across our IL counties. At
the SFC, cooler and drier air assoc with high pressure building into
the region from the nthrn Plains will cause high temps to be some 5-10
degrees cooler than yesterday. Winds may gust 20-25 mph for awhile this
aftn as decent CAA drops 850 temps to the upper single digits by 00Z.

2%

.LONG TERM:  (Tonight through Friday)
Issued at 1116 PM CDT Sat Sep 20 2014

The short wave pushes SE of the region Sunday night. The long wave
trough moves off the East Coast early in the week as a ridge
builds across the Plains. This should be a very quiet week with
clear to mostly clear skies and dry conditions. Monday should be
the coolest day with highs holding in the lower 70s with 850 temps
still in the upper single digits. Monday night is expected to be
the coolest night of the week with the high drifting overhead
allowing most locations to drop into the 40s. A slow warming trend
will ensue on Tuesday as 850 temps warm into the low/mid teens.
850 temps are not expected to change much thru the remainder of
the week meaning any addtnl warming will arise from air mass
modification. Temps are fcst to rise a degree or two each day thru
Friday when highs should be near 80. The center of the SFC ridge
slides off the NE coast on Wednesday only to have the center
reform well to the west across the Grt Lks towards the end of the
work week. This keeps the ridge axis anchored thru the CWA and
maintains the E/SE flow thru Friday. With the sfc ridge in this
orientation...the coolest overnight lows should remain across
sthrn IL and SE MO thru the week. A caveat to this fcst is energy
coming onshore this wknd across CA. The closed 500mb low is fcst
to undercut the ridge and eventually be absorbed into the mean
flow by the middle of the week. This feature is fcst to leave a
weakness in the upper ridge across the center of the country that
persists thru the end of the week. Guidance doesn`t generally
handle this type of scenario very well...which means I am not
confident what affect this will have on the sensible wx. Am
inclined to think that this will not be an issue and have gone
with a dry fcst but...this feature bears watching.

2%

&&

.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 633 PM CDT Sat Sep 20 2014

Scattered thunderstorms are possible this evening ahead of an
approaching cold front, but coverage is expected to be limited.
Winds will become northwesterly after fropa and gust to around 20
kts tomorrow. Generally VFR conditions are expected outside of
thunderstorms.

42

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX






000
FXUS63 KLSX 210504
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1204 AM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 335 PM CDT Sat Sep 20 2014

Main question for tonight is the convective trends and evolution.
The surface cold front is still far removed from the CWA, extending
from central Iowa through southeast Nebraska into northern Kansas at
mid afternoon. A fairly broad region of low level confluent flow is
located ahead of the front from northern IL into northern MO and
northeast KS where SBCAPE ranges from 1500-2500 j/kg. Convection
allowing models differ considerably on evolution of storms and don`t
offer much support. The visible satellite is showing agitated cu
within the confluent zone where the cirrus has been thinning. The
shortwave tracking across the upper MS Valley will bring some weak
mid level cooling further reducing any CIN, but large scale
support is largely weak or non-existent. Present thought is that
scattered thunderstorms will develop within this confluent zone
during the later part of this afternoon and evening. Can`t see
much better than scattered coverage unless we see areas of
storm/cold pool mergers. Greatest coverage should be this evening,
waning overnight with loss of instability as the cold front moves
southeastward through the area.

Glass

.LONG TERM:  (Sunday through Next Saturday)
Issued at 335 PM CDT Sat Sep 20 2014

The cold front should exit southern portions of the CWFA around
12-15Z on Sunday morning, thus ending the chance of precipitation
across the area through at least the first half of the work week.
Cooler and drier air filtering into the region in the wake of the
front Sunday will yield highs up to 10 degrees cooler for some
locations, with highs ranging from the low 70s north to near 80
degrees over far southern zones. Northwest flow will persist over the
region through the first part of the week as high pressure builds in
over the central US, with highs Monday and Tuesday only reaching the
low to middle 70s area-wide.  Beginning Wednesday, temperatures will
start to slowly rebound as surface high pressure drifts to the east
allowing for southerly flow to return, with highs reaching the upper
70s to around 80 degrees by Friday and Saturday.

A low pressure system currently off the central California coast
is still progged to come ashore and lift through the Rockies
toward the north central Plains by Tuesday night, though models
differ on the behavior of the low from that point forward. The GFS
and GEM both show the low retrograding southwestward prior to
making any impact on our area, whereas the ECMWF absorbs it into
the mean flow, lifting it quickly toward the upper Midwest and
Great Lakes. This feature could bring some increased cloud cover
and precipitation to northeast and mid Missouri in the Wednesday
night/Thursday time frame, though confidence is low until future
model runs come into better agreement. Other than this mid-week
feature, the extended looks to be dry and seasonably cool through
the start of next weekend.

Phillipson

&&

.AVIATION:  (For the 06z TAFs through 06z Sunday Night)
Issued at 1152 PM CDT Sat Sep 20 2014

Widely scattered thunderstorms may clip the 10-nm vicinity around
KCPS over the next few hours. It rained briefly at KUIN earlier in
the evening, and the additional moisture at low levels combined
with radiational cooling may continue to produce light fog over
the next few hours until wind speeds increase after fropa. VFR
conditions are expected at KCOU and KSUS. Expect winds to become
northwesterly at KSUS/KCPS/KCOU/KUIN after fropa, then gust to
around 20-25 kts with diurnal mixing. Gusts should subside after
sunset.

Specifics for KSTL: Widely scattered thunderstorms may clip the
10-nm vicinity of the terminal over the next few hours. Will
continue to monitor radar trends and amend if necessary.
Otherwise, expect winds to become northwesterly after fropa
overnight, then gust to 20-25 kts with diurnal mixing. Gusts
should subside after sunset. VFR conditions are expected outside
of thunderstorms.

42

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 210504
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1204 AM CDT Sun Sep 21 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 335 PM CDT Sat Sep 20 2014

Main question for tonight is the convective trends and evolution.
The surface cold front is still far removed from the CWA, extending
from central Iowa through southeast Nebraska into northern Kansas at
mid afternoon. A fairly broad region of low level confluent flow is
located ahead of the front from northern IL into northern MO and
northeast KS where SBCAPE ranges from 1500-2500 j/kg. Convection
allowing models differ considerably on evolution of storms and don`t
offer much support. The visible satellite is showing agitated cu
within the confluent zone where the cirrus has been thinning. The
shortwave tracking across the upper MS Valley will bring some weak
mid level cooling further reducing any CIN, but large scale
support is largely weak or non-existent. Present thought is that
scattered thunderstorms will develop within this confluent zone
during the later part of this afternoon and evening. Can`t see
much better than scattered coverage unless we see areas of
storm/cold pool mergers. Greatest coverage should be this evening,
waning overnight with loss of instability as the cold front moves
southeastward through the area.

Glass

.LONG TERM:  (Sunday through Next Saturday)
Issued at 335 PM CDT Sat Sep 20 2014

The cold front should exit southern portions of the CWFA around
12-15Z on Sunday morning, thus ending the chance of precipitation
across the area through at least the first half of the work week.
Cooler and drier air filtering into the region in the wake of the
front Sunday will yield highs up to 10 degrees cooler for some
locations, with highs ranging from the low 70s north to near 80
degrees over far southern zones. Northwest flow will persist over the
region through the first part of the week as high pressure builds in
over the central US, with highs Monday and Tuesday only reaching the
low to middle 70s area-wide.  Beginning Wednesday, temperatures will
start to slowly rebound as surface high pressure drifts to the east
allowing for southerly flow to return, with highs reaching the upper
70s to around 80 degrees by Friday and Saturday.

A low pressure system currently off the central California coast
is still progged to come ashore and lift through the Rockies
toward the north central Plains by Tuesday night, though models
differ on the behavior of the low from that point forward. The GFS
and GEM both show the low retrograding southwestward prior to
making any impact on our area, whereas the ECMWF absorbs it into
the mean flow, lifting it quickly toward the upper Midwest and
Great Lakes. This feature could bring some increased cloud cover
and precipitation to northeast and mid Missouri in the Wednesday
night/Thursday time frame, though confidence is low until future
model runs come into better agreement. Other than this mid-week
feature, the extended looks to be dry and seasonably cool through
the start of next weekend.

Phillipson

&&

.AVIATION:  (For the 06z TAFs through 06z Sunday Night)
Issued at 1152 PM CDT Sat Sep 20 2014

Widely scattered thunderstorms may clip the 10-nm vicinity around
KCPS over the next few hours. It rained briefly at KUIN earlier in
the evening, and the additional moisture at low levels combined
with radiational cooling may continue to produce light fog over
the next few hours until wind speeds increase after fropa. VFR
conditions are expected at KCOU and KSUS. Expect winds to become
northwesterly at KSUS/KCPS/KCOU/KUIN after fropa, then gust to
around 20-25 kts with diurnal mixing. Gusts should subside after
sunset.

Specifics for KSTL: Widely scattered thunderstorms may clip the
10-nm vicinity of the terminal over the next few hours. Will
continue to monitor radar trends and amend if necessary.
Otherwise, expect winds to become northwesterly after fropa
overnight, then gust to 20-25 kts with diurnal mixing. Gusts
should subside after sunset. VFR conditions are expected outside
of thunderstorms.

42

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 210020
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
720 PM CDT Sat Sep 20 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 335 PM CDT Sat Sep 20 2014

Main question for tonight is the convective trends and evolution.
The surface cold front is still far removed from the CWA, extending
from central Iowa through southeast Nebraska into northern Kansas at
mid afternoon. A fairly broad region of low level confluent flow is
located ahead of the front from northern IL into northern MO and
northeast KS where SBCAPE ranges from 1500-2500 j/kg. Convection
allowing models differ considerably on evolution of storms and don`t
offer much support. The visible satellite is showing agitated cu
within the confluent zone where the cirrus has been thinning. The
shortwave tracking across the upper MS Valley will bring some weak
mid level cooling further reducing any CIN, but large scale
support is largely weak or non-existent. Present thought is that
scattered thunderstorms will develop within this confluent zone
during the later part of this afternoon and evening. Can`t see
much better than scattered coverage unless we see areas of
storm/cold pool mergers. Greatest coverage should be this evening,
waning overnight with loss of instability as the cold front moves
southeastward through the area.

Glass

.LONG TERM:  (Sunday through Next Saturday)
Issued at 335 PM CDT Sat Sep 20 2014

The cold front should exit southern portions of the CWFA around
12-15Z on Sunday morning, thus ending the chance of precipitation
across the area through at least the first half of the work week.
Cooler and drier air filtering into the region in the wake of the
front Sunday will yield highs up to 10 degrees cooler for some
locations, with highs ranging from the low 70s north to near 80
degrees over far southern zones. Northwest flow will persist over the
region through the first part of the week as high pressure builds in
over the central US, with highs Monday and Tuesday only reaching the
low to middle 70s area-wide.  Beginning Wednesday, temperatures will
start to slowly rebound as surface high pressure drifts to the east
allowing for southerly flow to return, with highs reaching the upper
70s to around 80 degrees by Friday and Saturday.

A low pressure system currently off the central California coast
is still progged to come ashore and lift through the Rockies
toward the north central Plains by Tuesday night, though models
differ on the behavior of the low from that point forward. The GFS
and GEM both show the low retrograding southwestward prior to
making any impact on our area, whereas the ECMWF absorbs it into
the mean flow, lifting it quickly toward the upper Midwest and
Great Lakes. This feature could bring some increased cloud cover
and precipitation to northeast and mid Missouri in the Wednesday
night/Thursday time frame, though confidence is low until future
model runs come into better agreement. Other than this mid-week
feature, the extended looks to be dry and seasonably cool through
the start of next weekend.

Phillipson

&&

.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 633 PM CDT Sat Sep 20 2014

Scattered thunderstorms are possible this evening ahead of an
approaching cold front, but coverage is expected to be limited.
Winds will become northwesterly after fropa and gust to around 20
kts tomorrow. Generally VFR conditions are expected outside of
thunderstorms.

42

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 210020
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
720 PM CDT Sat Sep 20 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 335 PM CDT Sat Sep 20 2014

Main question for tonight is the convective trends and evolution.
The surface cold front is still far removed from the CWA, extending
from central Iowa through southeast Nebraska into northern Kansas at
mid afternoon. A fairly broad region of low level confluent flow is
located ahead of the front from northern IL into northern MO and
northeast KS where SBCAPE ranges from 1500-2500 j/kg. Convection
allowing models differ considerably on evolution of storms and don`t
offer much support. The visible satellite is showing agitated cu
within the confluent zone where the cirrus has been thinning. The
shortwave tracking across the upper MS Valley will bring some weak
mid level cooling further reducing any CIN, but large scale
support is largely weak or non-existent. Present thought is that
scattered thunderstorms will develop within this confluent zone
during the later part of this afternoon and evening. Can`t see
much better than scattered coverage unless we see areas of
storm/cold pool mergers. Greatest coverage should be this evening,
waning overnight with loss of instability as the cold front moves
southeastward through the area.

Glass

.LONG TERM:  (Sunday through Next Saturday)
Issued at 335 PM CDT Sat Sep 20 2014

The cold front should exit southern portions of the CWFA around
12-15Z on Sunday morning, thus ending the chance of precipitation
across the area through at least the first half of the work week.
Cooler and drier air filtering into the region in the wake of the
front Sunday will yield highs up to 10 degrees cooler for some
locations, with highs ranging from the low 70s north to near 80
degrees over far southern zones. Northwest flow will persist over the
region through the first part of the week as high pressure builds in
over the central US, with highs Monday and Tuesday only reaching the
low to middle 70s area-wide.  Beginning Wednesday, temperatures will
start to slowly rebound as surface high pressure drifts to the east
allowing for southerly flow to return, with highs reaching the upper
70s to around 80 degrees by Friday and Saturday.

A low pressure system currently off the central California coast
is still progged to come ashore and lift through the Rockies
toward the north central Plains by Tuesday night, though models
differ on the behavior of the low from that point forward. The GFS
and GEM both show the low retrograding southwestward prior to
making any impact on our area, whereas the ECMWF absorbs it into
the mean flow, lifting it quickly toward the upper Midwest and
Great Lakes. This feature could bring some increased cloud cover
and precipitation to northeast and mid Missouri in the Wednesday
night/Thursday time frame, though confidence is low until future
model runs come into better agreement. Other than this mid-week
feature, the extended looks to be dry and seasonably cool through
the start of next weekend.

Phillipson

&&

.AVIATION:  (For the 00z TAFs through 00z Sunday Evening)
Issued at 633 PM CDT Sat Sep 20 2014

Scattered thunderstorms are possible this evening ahead of an
approaching cold front, but coverage is expected to be limited.
Winds will become northwesterly after fropa and gust to around 20
kts tomorrow. Generally VFR conditions are expected outside of
thunderstorms.

42

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 202037
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
337 PM CDT Sat Sep 20 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 335 PM CDT Sat Sep 20 2014

Main question for tonight is the convective trends and evolution.
The surface cold front is still far removed from the CWA, extending
from central Iowa through southeast Nebraska into northern Kansas at
mid afternoon. A fairly broad region of low level confluent flow is
located ahead of the front from northern IL into northern MO and
northeast KS where SBCAPE ranges from 1500-2500 j/kg. Convection
allowing models differ considerably on evolution of storms and don`t
offer much support. The visible satellite is showing agitated cu
within the confluent zone where the cirrus has been thinning. The
shortwave tracking across the upper MS Valley will bring some weak
mid level cooling further reducing any CIN, but large scale
support is largely weak or non-existent. Present thought is that
scattered thunderstorms will develop within this confluent zone
during the later part of this afternoon and evening. Can`t see
much better than scattered coverage unless we see areas of
storm/cold pool mergers. Greatest coverage should be this evening,
waning overnight with loss of instability as the cold front moves
southeastward through the area.

Glass

.LONG TERM:  (Sunday through Next Saturday)
Issued at 335 PM CDT Sat Sep 20 2014

The cold front should exit southern portions of the CWFA around
12-15Z on Sunday morning, thus ending the chance of precipitation
across the area through at least the first half of the work week.
Cooler and drier air filtering into the region in the wake of the
front Sunday will yield highs up to 10 degrees cooler for some
locations, with highs ranging from the low 70s north to near 80
degrees over far southern zones. Northwest flow will persist over the
region through the first part of the week as high pressure builds in
over the central US, with highs Monday and Tuesday only reaching the
low to middle 70s area-wide.  Beginning Wednesday, temperatures will
start to slowly rebound as surface high pressure drifts to the east
allowing for southerly flow to return, with highs reaching the upper
70s to around 80 degrees by Friday and Saturday.

A low pressure system currently off the central California coast
is still progged to come ashore and lift through the Rockies
toward the north central Plains by Tuesday night, though models
differ on the behavior of the low from that point forward. The GFS
and GEM both show the low retrograding southwestward prior to
making any impact on our area, whereas the ECMWF absorbs it into
the mean flow, lifting it quickly toward the upper Midwest and
Great Lakes. This feature could bring some increased cloud cover
and precipitation to northeast and mid Missouri in the Wednesday
night/Thursday time frame, though confidence is low until future
model runs come into better agreement. Other than this mid-week
feature, the extended looks to be dry and seasonably cool through
the start of next weekend.

Phillipson

&&

.AVIATION:  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1233 PM CDT Sat Sep 20 2014

The main forecast issue is the threat of showers and thunderstorms
this afternoon and evening. A cold front will be pushing into
northern MO later this afternoon and moving southward across the
area tonight. Scattered showers and thunderstorms should develop
across northern MO into central IL this afternoon in a zone
along/ahead of the front. Coverage should be greatest from the
late afternoon into the evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts and thus have kept with VCTS in the TAFS. Gusty
southwest winds will prevail this afternoon in advance of the
front, with gusty north northwest winds on Sunday.

Specifics for KSTL:

The main forecast issue is the threat of showers and thunderstorms
this evening. A cold front will be pushing into northern MO later
this afternoon and moving southward across the area tonight.
Scattered showers and thunderstorms should develop across northern
MO into central IL this afternoon in a zone along/ahead of the
front and move southeast. Coverage should be greatest from the
late afternoon into mid evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts at KSTL and thus have kept with VCTS in the TAFS.
Gusty southwest winds will prevail this afternoon in advance of
the front, with gusty north northwest winds on Sunday.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 202037
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
337 PM CDT Sat Sep 20 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 335 PM CDT Sat Sep 20 2014

Main question for tonight is the convective trends and evolution.
The surface cold front is still far removed from the CWA, extending
from central Iowa through southeast Nebraska into northern Kansas at
mid afternoon. A fairly broad region of low level confluent flow is
located ahead of the front from northern IL into northern MO and
northeast KS where SBCAPE ranges from 1500-2500 j/kg. Convection
allowing models differ considerably on evolution of storms and don`t
offer much support. The visible satellite is showing agitated cu
within the confluent zone where the cirrus has been thinning. The
shortwave tracking across the upper MS Valley will bring some weak
mid level cooling further reducing any CIN, but large scale
support is largely weak or non-existent. Present thought is that
scattered thunderstorms will develop within this confluent zone
during the later part of this afternoon and evening. Can`t see
much better than scattered coverage unless we see areas of
storm/cold pool mergers. Greatest coverage should be this evening,
waning overnight with loss of instability as the cold front moves
southeastward through the area.

Glass

.LONG TERM:  (Sunday through Next Saturday)
Issued at 335 PM CDT Sat Sep 20 2014

The cold front should exit southern portions of the CWFA around
12-15Z on Sunday morning, thus ending the chance of precipitation
across the area through at least the first half of the work week.
Cooler and drier air filtering into the region in the wake of the
front Sunday will yield highs up to 10 degrees cooler for some
locations, with highs ranging from the low 70s north to near 80
degrees over far southern zones. Northwest flow will persist over the
region through the first part of the week as high pressure builds in
over the central US, with highs Monday and Tuesday only reaching the
low to middle 70s area-wide.  Beginning Wednesday, temperatures will
start to slowly rebound as surface high pressure drifts to the east
allowing for southerly flow to return, with highs reaching the upper
70s to around 80 degrees by Friday and Saturday.

A low pressure system currently off the central California coast
is still progged to come ashore and lift through the Rockies
toward the north central Plains by Tuesday night, though models
differ on the behavior of the low from that point forward. The GFS
and GEM both show the low retrograding southwestward prior to
making any impact on our area, whereas the ECMWF absorbs it into
the mean flow, lifting it quickly toward the upper Midwest and
Great Lakes. This feature could bring some increased cloud cover
and precipitation to northeast and mid Missouri in the Wednesday
night/Thursday time frame, though confidence is low until future
model runs come into better agreement. Other than this mid-week
feature, the extended looks to be dry and seasonably cool through
the start of next weekend.

Phillipson

&&

.AVIATION:  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1233 PM CDT Sat Sep 20 2014

The main forecast issue is the threat of showers and thunderstorms
this afternoon and evening. A cold front will be pushing into
northern MO later this afternoon and moving southward across the
area tonight. Scattered showers and thunderstorms should develop
across northern MO into central IL this afternoon in a zone
along/ahead of the front. Coverage should be greatest from the
late afternoon into the evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts and thus have kept with VCTS in the TAFS. Gusty
southwest winds will prevail this afternoon in advance of the
front, with gusty north northwest winds on Sunday.

Specifics for KSTL:

The main forecast issue is the threat of showers and thunderstorms
this evening. A cold front will be pushing into northern MO later
this afternoon and moving southward across the area tonight.
Scattered showers and thunderstorms should develop across northern
MO into central IL this afternoon in a zone along/ahead of the
front and move southeast. Coverage should be greatest from the
late afternoon into mid evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts at KSTL and thus have kept with VCTS in the TAFS.
Gusty southwest winds will prevail this afternoon in advance of
the front, with gusty north northwest winds on Sunday.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 201743
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1243 PM CDT Sat Sep 20 2014

.UPDATE:
Issued at 1233 PM CDT Sat Sep 20 2014

I`ve added some low pops to portions of southeast Missouri and far
southwest Illinois for this afternoon. It appears a gravity wave
has interacted with a more robust cu field along and south of a
line from St. Clair to Belleville where SBCAPE is from 1500-2000
j/kg and little CIN. This interaction has produced the development
of some spotty showers within the last 30 minutes.

Glass

&&

.SHORT TERM: (Through Tonight)
Issued at 214 AM CDT Sat Sep 20 2014

This prd will focus on approaching cold front that currently
stretches from cntrl MN SW across far NW IA...NE and eventually NE
CO. This feature is being driven by a significant short wave
dropping thru the Grt Lks. This bndry will slowly work south thru
the day. Guidance has slowed this feature over the past 24 hrs. It
is not expected to reach our NE MO counties until closer to
midnight and not clear SE MO until early Sunday mrng. There is some
potential of convection breaking out ahead of the front this aftn
as a vort max and weakness in the sfc pressure field/wind shift may
be enough to initiate at least some isld convection. Even if
SHRAs/TSTMs are able to dvlp this aftn...the better precip
coverage will be this evng thru the overnight hrs. SPC has areas
north of I70 under a slight risk of SVR wx. This looks reasonable
based on temps in the mid/upper 80s with Dps in the upper 60s to
near 70 producing SB CAPE values in excess of 3000 J/kg and MU
CAPE in excess of 2000 J/kg and 0-6km shear values of 30-45kts.
There is also a significant mid and upper level jet max nosing
into IA and nthrn IL from the Dakotas. So, any storms that can
get going have the potential to become svr, with large hail and
damaging winds being the primary threats. I think that there is a
relatively small window for svr convection from late aftn thru mid
evng before the bndry layer cools enough to limit buoyancy. The
NAM indicates significant levels of CAPE, around 1000 J/kg, to exist
thru the night. This solution is an outlier with the remainder of
the guidance indicating CAPE to decrease significantly after 6Z.
So, expect convection to continue south thru the night weakening
in the process.

2%

.LONG TERM: (Sunday through Friday)
Issued at 214 AM CDT Sat Sep 20 2014

The cold front should clear the sthrn CWA around 12Z with any
lingering precip mvng out shortly thereafter. A secondary short
wave will pass just to the NE of the area Sunday. Due to the first
impulse clearing out the moisture, this second shortwave is not
expected to have much impact on the sensible wx other than maybe
some increased cloudiness across our IL counties. Beyond this
feature, high pressure will be in control for the remainder of the
week as an upper level ridge builds across the Plains providing
mostly clear skies and dry conditions. Temps will start the first
half of the week in the low/mid 70s and should moderate to near 80
by Friday. One caveat to this scenario is a closed low off the CA
coast that is fcst to come onshore this wknd and tries to undercut
the ridge but gets absorbed into the mean flow as the week
progresses. I don`t expect this feature to have a significant
effect on the sensible wx attm...but that could change as the week
moves forward.

2%

&&

.AVIATION:  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1233 PM CDT Sat Sep 20 2014

The main forecast issue is the threat of showers and thunderstorms
this afternoon and evening. A cold front will be pushing into
northern MO later this afternoon and moving southward across the
area tonight. Scattered showers and thunderstorms should develop
across northern MO into central IL this afternoon in a zone
along/ahead of the front. Coverage should be greatest from the
late afternoon into the evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts and thus have kept with VCTS in the TAFS. Gusty
southwest winds will prevail this afternoon in advance of the
front, with gusty north northwest winds on Sunday.

Specifics for KSTL:

The main forecast issue is the threat of showers and thunderstorms
this evening. A cold front will be pushing into northern MO later
this afternoon and moving southward across the area tonight.
Scattered showers and thunderstorms should develop across northern
MO into central IL this afternoon in a zone along/ahead of the
front and move southeast. Coverage should be greatest from the
late afternoon into mid evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts at KSTL and thus have kept with VCTS in the TAFS.
Gusty southwest winds will prevail this afternoon in advance of
the front, with gusty north northwest winds on Sunday.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 201743
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1243 PM CDT Sat Sep 20 2014

.UPDATE:
Issued at 1233 PM CDT Sat Sep 20 2014

I`ve added some low pops to portions of southeast Missouri and far
southwest Illinois for this afternoon. It appears a gravity wave
has interacted with a more robust cu field along and south of a
line from St. Clair to Belleville where SBCAPE is from 1500-2000
j/kg and little CIN. This interaction has produced the development
of some spotty showers within the last 30 minutes.

Glass

&&

.SHORT TERM: (Through Tonight)
Issued at 214 AM CDT Sat Sep 20 2014

This prd will focus on approaching cold front that currently
stretches from cntrl MN SW across far NW IA...NE and eventually NE
CO. This feature is being driven by a significant short wave
dropping thru the Grt Lks. This bndry will slowly work south thru
the day. Guidance has slowed this feature over the past 24 hrs. It
is not expected to reach our NE MO counties until closer to
midnight and not clear SE MO until early Sunday mrng. There is some
potential of convection breaking out ahead of the front this aftn
as a vort max and weakness in the sfc pressure field/wind shift may
be enough to initiate at least some isld convection. Even if
SHRAs/TSTMs are able to dvlp this aftn...the better precip
coverage will be this evng thru the overnight hrs. SPC has areas
north of I70 under a slight risk of SVR wx. This looks reasonable
based on temps in the mid/upper 80s with Dps in the upper 60s to
near 70 producing SB CAPE values in excess of 3000 J/kg and MU
CAPE in excess of 2000 J/kg and 0-6km shear values of 30-45kts.
There is also a significant mid and upper level jet max nosing
into IA and nthrn IL from the Dakotas. So, any storms that can
get going have the potential to become svr, with large hail and
damaging winds being the primary threats. I think that there is a
relatively small window for svr convection from late aftn thru mid
evng before the bndry layer cools enough to limit buoyancy. The
NAM indicates significant levels of CAPE, around 1000 J/kg, to exist
thru the night. This solution is an outlier with the remainder of
the guidance indicating CAPE to decrease significantly after 6Z.
So, expect convection to continue south thru the night weakening
in the process.

2%

.LONG TERM: (Sunday through Friday)
Issued at 214 AM CDT Sat Sep 20 2014

The cold front should clear the sthrn CWA around 12Z with any
lingering precip mvng out shortly thereafter. A secondary short
wave will pass just to the NE of the area Sunday. Due to the first
impulse clearing out the moisture, this second shortwave is not
expected to have much impact on the sensible wx other than maybe
some increased cloudiness across our IL counties. Beyond this
feature, high pressure will be in control for the remainder of the
week as an upper level ridge builds across the Plains providing
mostly clear skies and dry conditions. Temps will start the first
half of the week in the low/mid 70s and should moderate to near 80
by Friday. One caveat to this scenario is a closed low off the CA
coast that is fcst to come onshore this wknd and tries to undercut
the ridge but gets absorbed into the mean flow as the week
progresses. I don`t expect this feature to have a significant
effect on the sensible wx attm...but that could change as the week
moves forward.

2%

&&

.AVIATION:  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1233 PM CDT Sat Sep 20 2014

The main forecast issue is the threat of showers and thunderstorms
this afternoon and evening. A cold front will be pushing into
northern MO later this afternoon and moving southward across the
area tonight. Scattered showers and thunderstorms should develop
across northern MO into central IL this afternoon in a zone
along/ahead of the front. Coverage should be greatest from the
late afternoon into the evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts and thus have kept with VCTS in the TAFS. Gusty
southwest winds will prevail this afternoon in advance of the
front, with gusty north northwest winds on Sunday.

Specifics for KSTL:

The main forecast issue is the threat of showers and thunderstorms
this evening. A cold front will be pushing into northern MO later
this afternoon and moving southward across the area tonight.
Scattered showers and thunderstorms should develop across northern
MO into central IL this afternoon in a zone along/ahead of the
front and move southeast. Coverage should be greatest from the
late afternoon into mid evening and diminish overnight. Given the
low coverage of storms I have limited confidence in any direct
terminal impacts at KSTL and thus have kept with VCTS in the TAFS.
Gusty southwest winds will prevail this afternoon in advance of
the front, with gusty north northwest winds on Sunday.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 201154
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
654 AM CDT Sat Sep 20 2014

.SHORT TERM: (Through Tonight)
Issued at 214 AM CDT Sat Sep 20 2014

This prd will focus on approaching cold front that currently
stretches from cntrl MN SW across far NW IA...NE and eventually NE
CO. This feature is being driven by a significant short wave
dropping thru the Grt Lks. This bndry will slowly work south thru
the day. Guidance has slowed this feature over the past 24 hrs. It
is not expected to reach our NE MO counties until closer to
midnight and not clear SE MO until early Sunday mrng. There is some
potential of convection breaking out ahead of the front this aftn
as a vort max and weakness in the sfc pressure field/wind shift may
be enough to initiate at least some isld convection. Even if
SHRAs/TSTMs are able to dvlp this aftn...the better precip
coverage will be this evng thru the overnight hrs. SPC has areas
north of I70 under a slight risk of SVR wx. This looks reasonable
based on temps in the mid/upper 80s with Dps in the upper 60s to
near 70 producing SB CAPE values in excess of 3000 J/kg and MU
CAPE in excess of 2000 J/kg and 0-6km shear values of 30-45kts.
There is also a significant mid and upper level jet max nosing
into IA and nthrn IL from the Dakotas. So, any storms that can
get going have the potential to become svr, with large hail and
damaging winds being the primary threats. I think that there is a
relatively small window for svr convection from late aftn thru mid
evng before the bndry layer cools enough to limit buoyancy. The
NAM indicates significant levels of CAPE, around 1000 J/kg, to exist
thru the night. This solution is an outlier with the remainder of
the guidance indicating CAPE to decrease significantly after 6Z.
So, expect convection to continue south thru the night weakening
in the process.

2%

.LONG TERM: (Sunday through Friday)
Issued at 214 AM CDT Sat Sep 20 2014

The cold front should clear the sthrn CWA around 12Z with any
lingering precip mvng out shortly thereafter. A secondary short
wave will pass just to the NE of the area Sunday. Due to the first
impulse clearing out the moisture, this second shortwave is not
expected to have much impact on the sensible wx other than maybe
some increased cloudiness across our IL counties. Beyond this
feature, high pressure will be in control for the remainder of the
week as an upper level ridge builds across the Plains providing
mostly clear skies and dry conditions. Temps will start the first
half of the week in the low/mid 70s and should moderate to near 80
by Friday. One caveat to this scenario is a closed low off the CA
coast that is fcst to come onshore this wknd and tries to undercut
the ridge but gets absorbed into the mean flow as the week
progresses. I don`t expect this feature to have a significant
effect on the sensible wx attm...but that could change as the week
moves forward.

2%

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 630 AM CDT Sat Sep 20 2014

Focus continues to be TSRA chances thru tonight. FG will quickly
dissipate this morning with sunrise. Ongoing TSRA over srn IA will
continue to dissipate this morning. Storms are expected to impact
terminals this afternoon and into the evening ahead of an
approaching cdfnt. These storms may be strong to severe with
damaging wind gusts as the main threat. Can not rule out SCT TSRA
around/just before 18z today. However, SCT nature of storms and
uncertainty is too great to mention in TAF attm. Otherwise, winds
will become nwly behind the fnt.

Specifics for KSTL: Main threat for TSRA will be this eve ahead of
approaching cdfnt. However, can not rule out a SCT TSRA impacting
the terminal around 18z today. Storms this evening are no longer
expected to be severe, but wind gusts to around 45 kts may be
possible. Winds will become nwly behind the fnt late in the
period.

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 201154
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
654 AM CDT Sat Sep 20 2014

.SHORT TERM: (Through Tonight)
Issued at 214 AM CDT Sat Sep 20 2014

This prd will focus on approaching cold front that currently
stretches from cntrl MN SW across far NW IA...NE and eventually NE
CO. This feature is being driven by a significant short wave
dropping thru the Grt Lks. This bndry will slowly work south thru
the day. Guidance has slowed this feature over the past 24 hrs. It
is not expected to reach our NE MO counties until closer to
midnight and not clear SE MO until early Sunday mrng. There is some
potential of convection breaking out ahead of the front this aftn
as a vort max and weakness in the sfc pressure field/wind shift may
be enough to initiate at least some isld convection. Even if
SHRAs/TSTMs are able to dvlp this aftn...the better precip
coverage will be this evng thru the overnight hrs. SPC has areas
north of I70 under a slight risk of SVR wx. This looks reasonable
based on temps in the mid/upper 80s with Dps in the upper 60s to
near 70 producing SB CAPE values in excess of 3000 J/kg and MU
CAPE in excess of 2000 J/kg and 0-6km shear values of 30-45kts.
There is also a significant mid and upper level jet max nosing
into IA and nthrn IL from the Dakotas. So, any storms that can
get going have the potential to become svr, with large hail and
damaging winds being the primary threats. I think that there is a
relatively small window for svr convection from late aftn thru mid
evng before the bndry layer cools enough to limit buoyancy. The
NAM indicates significant levels of CAPE, around 1000 J/kg, to exist
thru the night. This solution is an outlier with the remainder of
the guidance indicating CAPE to decrease significantly after 6Z.
So, expect convection to continue south thru the night weakening
in the process.

2%

.LONG TERM: (Sunday through Friday)
Issued at 214 AM CDT Sat Sep 20 2014

The cold front should clear the sthrn CWA around 12Z with any
lingering precip mvng out shortly thereafter. A secondary short
wave will pass just to the NE of the area Sunday. Due to the first
impulse clearing out the moisture, this second shortwave is not
expected to have much impact on the sensible wx other than maybe
some increased cloudiness across our IL counties. Beyond this
feature, high pressure will be in control for the remainder of the
week as an upper level ridge builds across the Plains providing
mostly clear skies and dry conditions. Temps will start the first
half of the week in the low/mid 70s and should moderate to near 80
by Friday. One caveat to this scenario is a closed low off the CA
coast that is fcst to come onshore this wknd and tries to undercut
the ridge but gets absorbed into the mean flow as the week
progresses. I don`t expect this feature to have a significant
effect on the sensible wx attm...but that could change as the week
moves forward.

2%

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 630 AM CDT Sat Sep 20 2014

Focus continues to be TSRA chances thru tonight. FG will quickly
dissipate this morning with sunrise. Ongoing TSRA over srn IA will
continue to dissipate this morning. Storms are expected to impact
terminals this afternoon and into the evening ahead of an
approaching cdfnt. These storms may be strong to severe with
damaging wind gusts as the main threat. Can not rule out SCT TSRA
around/just before 18z today. However, SCT nature of storms and
uncertainty is too great to mention in TAF attm. Otherwise, winds
will become nwly behind the fnt.

Specifics for KSTL: Main threat for TSRA will be this eve ahead of
approaching cdfnt. However, can not rule out a SCT TSRA impacting
the terminal around 18z today. Storms this evening are no longer
expected to be severe, but wind gusts to around 45 kts may be
possible. Winds will become nwly behind the fnt late in the
period.

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 200817
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
317 AM CDT Sat Sep 20 2014

.SHORT TERM: (Through Tonight)
Issued at 214 AM CDT Sat Sep 20 2014

This prd will focus on approaching cold front that currently
stretches from cntrl MN SW across far NW IA...NE and eventually NE
CO. This feature is being driven by a significant short wave
dropping thru the Grt Lks. This bndry will slowly work south thru
the day. Guidance has slowed this feature over the past 24 hrs. It
is not expected to reach our NE MO counties until closer to
midnight and not clear SE MO until early Sunday mrng. There is some
potential of convection breaking out ahead of the front this aftn
as a vort max and weakness in the sfc pressure field/wind shift may
be enough to initiate at least some isld convection. Even if
SHRAs/TSTMs are able to dvlp this aftn...the better precip
coverage will be this evng thru the overnight hrs. SPC has areas
north of I70 under a slight risk of SVR wx. This looks reasonable
based on temps in the mid/upper 80s with Dps in the upper 60s to
near 70 producing SB CAPE values in excess of 3000 J/kg and MU
CAPE in excess of 2000 J/kg and 0-6km shear values of 30-45kts.
There is also a significant mid and upper level jet max nosing
into IA and nthrn IL from the Dakotas. So, any storms that can
get going have the potential to become svr, with large hail and
damaging winds being the primary threats. I think that there is a
relatively small window for svr convection from late aftn thru mid
evng before the bndry layer cools enough to limit buoyancy. The
NAM indicates significant levels of CAPE, around 1000 J/kg, to exist
thru the night. This solution is an outlier with the remainder of
the guidance indicating CAPE to decrease significantly after 6Z.
So, expect convection to continue south thru the night weakening
in the process.

2%

.LONG TERM: (Sunday through Friday)
Issued at 214 AM CDT Sat Sep 20 2014

The cold front should clear the sthrn CWA around 12Z with any
lingering precip mvng out shortly thereafter. A secondary short
wave will pass just to the NE of the area Sunday. Due to the first
impulse clearing out the moisture, this second shortwave is not
expected to have much impact on the sensible wx other than maybe
some increased cloudiness across our IL counties. Beyond this
feature, high pressure will be in control for the remainder of the
week as an upper level ridge builds across the Plains providing
mostly clear skies and dry conditions. Temps will start the first
half of the week in the low/mid 70s and should moderate to near 80
by Friday. One caveat to this scenario is a closed low off the CA
coast that is fcst to come onshore this wknd and tries to undercut
the ridge but gets absorbed into the mean flow as the week
progresses. I don`t expect this feature to have a significant
effect on the sensible wx attm...but that could change as the week
moves forward.

2%

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1150 PM CDT Fri Sep 19 2014

Still expect fog to develop within the next few hours at KSUS and
KCPS. Visibilities may drop as low as IFR at times. Otherwise
still expect scattered showers and thunderstorms to develop along
a cold front that will drop southward across the area tomorrow
afternoon and evening. Have introduced VCTS at the terminals to
indicate the best timing for thunderstorms near the airports.
Winds will veer from southwest to northwest behind the front.

Specifics for KSTL: Expect mainly VFR conditions until thunderstorms
move into the area along a cold front after 00Z. If thunderstorms
do move into the terminal, they may have MVFR conditions with
them. Winds will turn out of the southwest by 15Z, and then turn
out of the northwest behind the front on Saturday night.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 200817
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
317 AM CDT Sat Sep 20 2014

.SHORT TERM: (Through Tonight)
Issued at 214 AM CDT Sat Sep 20 2014

This prd will focus on approaching cold front that currently
stretches from cntrl MN SW across far NW IA...NE and eventually NE
CO. This feature is being driven by a significant short wave
dropping thru the Grt Lks. This bndry will slowly work south thru
the day. Guidance has slowed this feature over the past 24 hrs. It
is not expected to reach our NE MO counties until closer to
midnight and not clear SE MO until early Sunday mrng. There is some
potential of convection breaking out ahead of the front this aftn
as a vort max and weakness in the sfc pressure field/wind shift may
be enough to initiate at least some isld convection. Even if
SHRAs/TSTMs are able to dvlp this aftn...the better precip
coverage will be this evng thru the overnight hrs. SPC has areas
north of I70 under a slight risk of SVR wx. This looks reasonable
based on temps in the mid/upper 80s with Dps in the upper 60s to
near 70 producing SB CAPE values in excess of 3000 J/kg and MU
CAPE in excess of 2000 J/kg and 0-6km shear values of 30-45kts.
There is also a significant mid and upper level jet max nosing
into IA and nthrn IL from the Dakotas. So, any storms that can
get going have the potential to become svr, with large hail and
damaging winds being the primary threats. I think that there is a
relatively small window for svr convection from late aftn thru mid
evng before the bndry layer cools enough to limit buoyancy. The
NAM indicates significant levels of CAPE, around 1000 J/kg, to exist
thru the night. This solution is an outlier with the remainder of
the guidance indicating CAPE to decrease significantly after 6Z.
So, expect convection to continue south thru the night weakening
in the process.

2%

.LONG TERM: (Sunday through Friday)
Issued at 214 AM CDT Sat Sep 20 2014

The cold front should clear the sthrn CWA around 12Z with any
lingering precip mvng out shortly thereafter. A secondary short
wave will pass just to the NE of the area Sunday. Due to the first
impulse clearing out the moisture, this second shortwave is not
expected to have much impact on the sensible wx other than maybe
some increased cloudiness across our IL counties. Beyond this
feature, high pressure will be in control for the remainder of the
week as an upper level ridge builds across the Plains providing
mostly clear skies and dry conditions. Temps will start the first
half of the week in the low/mid 70s and should moderate to near 80
by Friday. One caveat to this scenario is a closed low off the CA
coast that is fcst to come onshore this wknd and tries to undercut
the ridge but gets absorbed into the mean flow as the week
progresses. I don`t expect this feature to have a significant
effect on the sensible wx attm...but that could change as the week
moves forward.

2%

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1150 PM CDT Fri Sep 19 2014

Still expect fog to develop within the next few hours at KSUS and
KCPS. Visibilities may drop as low as IFR at times. Otherwise
still expect scattered showers and thunderstorms to develop along
a cold front that will drop southward across the area tomorrow
afternoon and evening. Have introduced VCTS at the terminals to
indicate the best timing for thunderstorms near the airports.
Winds will veer from southwest to northwest behind the front.

Specifics for KSTL: Expect mainly VFR conditions until thunderstorms
move into the area along a cold front after 00Z. If thunderstorms
do move into the terminal, they may have MVFR conditions with
them. Winds will turn out of the southwest by 15Z, and then turn
out of the northwest behind the front on Saturday night.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 200451
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1151 PM CDT Fri Sep 19 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 317 PM CDT Fri Sep 19 2014

Surface ridge continues to move off to the east allowing southerly
flow to move back in. So it will be a bit milder tonight with lows
in the upper 50s to low 60s. With surface ridge still over far
southern portions of forecast area, plenty of low level moisture and
winds remaining light, could see some patchy fog over the eastern
Ozarks towards daybreak, so added mention.

Byrd

.LONG TERM:  (Saturday through Next Friday)
Issued at 317 PM CDT Fri Sep 19 2014

In the meantime, next weather system to move in by Saturday
afternoon with showers and thunderstorms developing and spreading
southeast across region as cold front moves through. Models have
some timing differences, so for now only made minor adjustments to
the grids. Best chances of precipitation will be Saturday afternoon
and evening before tapering off Sunday morning. Exact location of
where activity will initiate hard to pin down as well. Could see
some activity in morning with more stuff firing up by afternoon, as
for where, it will depend on where the cold front is.

On Sunday after system exits, begin to cool back down as next ridge
of high pressure builds in. Cooler and drier weather to persist
through the middle of next week with highs in the 70s and lows in
the 50s. Then as ridge slides off, temperatures to moderate by the
end of the work week.

Byrd

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1150 PM CDT Fri Sep 19 2014

Still expect fog to develop within the next few hours at KSUS and
KCPS. Visibilities may drop as low as IFR at times. Otherwise
still expect scattered showers and thunderstorms to develop along
a cold front that will drop southward across the area tomorrow
afternoon and evening. Have introduced VCTS at the terminals to
indicate the best timing for thunderstorms near the airports.
Winds will veer from southwest to northwest behind the front.

Specifics for KSTL: Expect mainly VFR conditions until thunderstorms
move into the area along a cold front after 00Z. If thunderstorms
do move into the terminal, they may have MVFR conditions with
them. Winds will turn out of the southwest by 15Z, and then turn
out of the northwest behind the front on Saturday night.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 200451
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1151 PM CDT Fri Sep 19 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 317 PM CDT Fri Sep 19 2014

Surface ridge continues to move off to the east allowing southerly
flow to move back in. So it will be a bit milder tonight with lows
in the upper 50s to low 60s. With surface ridge still over far
southern portions of forecast area, plenty of low level moisture and
winds remaining light, could see some patchy fog over the eastern
Ozarks towards daybreak, so added mention.

Byrd

.LONG TERM:  (Saturday through Next Friday)
Issued at 317 PM CDT Fri Sep 19 2014

In the meantime, next weather system to move in by Saturday
afternoon with showers and thunderstorms developing and spreading
southeast across region as cold front moves through. Models have
some timing differences, so for now only made minor adjustments to
the grids. Best chances of precipitation will be Saturday afternoon
and evening before tapering off Sunday morning. Exact location of
where activity will initiate hard to pin down as well. Could see
some activity in morning with more stuff firing up by afternoon, as
for where, it will depend on where the cold front is.

On Sunday after system exits, begin to cool back down as next ridge
of high pressure builds in. Cooler and drier weather to persist
through the middle of next week with highs in the 70s and lows in
the 50s. Then as ridge slides off, temperatures to moderate by the
end of the work week.

Byrd

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1150 PM CDT Fri Sep 19 2014

Still expect fog to develop within the next few hours at KSUS and
KCPS. Visibilities may drop as low as IFR at times. Otherwise
still expect scattered showers and thunderstorms to develop along
a cold front that will drop southward across the area tomorrow
afternoon and evening. Have introduced VCTS at the terminals to
indicate the best timing for thunderstorms near the airports.
Winds will veer from southwest to northwest behind the front.

Specifics for KSTL: Expect mainly VFR conditions until thunderstorms
move into the area along a cold front after 00Z. If thunderstorms
do move into the terminal, they may have MVFR conditions with
them. Winds will turn out of the southwest by 15Z, and then turn
out of the northwest behind the front on Saturday night.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







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