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000
FXUS63 KLSX 311543
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
943 AM CST Sat Jan 31 2015

.UPDATE:
Issued at 933 AM CST Sat Jan 31 2015

Brief update to delay onset/lower PoPs across the srn and ern
portions of the CWA. RA continues to move newd into the region.
Expect RA shield to remain along the wrn CWA border over the next
couple of hours, but precip will gradually move ewd/newd impacting
central and nern portions of MO into west central IL. A very brief
period of IP may be possible at the onset of precip. However, as
the onset of precip is delayed, the chances of this occurring are
reduced. Regardless, any IP shud be very brief and not pose an
impact.

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 327 AM CST Sat Jan 31 2015

Mid and high clouds to remain over region ahead of main weather
system. In the meantime, low level moisture and warm air advection
are on the increase on nose of low level jet. So rain will continue
to develop and spread eastward through much of our forecast area
today, especially north and west of St. Louis metro area. It will
mainly be in the form of rain but could see a brief period of snow
mixed in across central and northeast Missouri this morning. As for
high temperatures, they will be in the upper 30s to mid 40s.

Byrd

.LONG TERM:  (Tonight through Friday)
Issued at 327 AM CST Sat Jan 31 2015

(Tonight-Monday)

Obviously, main concern is ptypes and potential snowfall amounts
with storm system pushing into the region.  00z runs have continued
warming trend of low level temp profile in advance of the storm, and
given that this has been the trend for 4 straight model cycles
forecast has been adjusted "warmer" as well.  This adjustment will
manifest itself in a slower transition to all snow, and reduced
snowfall amounts over the central third of the CWA...along the I-70
corridor.

Certainly, best area for accumulations in our CWA will be our far
northern counties, and the key to the forecast is how soon the
precip transitions from rain to snow.  NAM forecast sounding for UIN
indicates some low level cooling that would cause the switch to
occur as early as 03z, while GFS is warmer/slower with cooling.
It`s also interesting, and perhaps a bit worrisome from a heavy
snowfall viewpoint, that both the NAM and GFS are nearly isothermal
at 0C at 12z up to 900mb, and a slight wiggle either warmer or
colder will have a dramatic impact on when the changeover occurs and
ultimately how much snowfall.

Based on this uncertainty have tried to be a bit conservative with
snowfall forecasts across the north, but working the numbers in
various ways still yields snowfall totals of around or just above 6
inches along and north of an Edina-Mount Sterling line, with
snowfall totals dropping off quickly as you head south...to no more
than an inch along a Mexico-Vandalia IL line.  Based on these
forecast amounts, will go with a Winter Storm Warning for our far
northern counties for tonight into Sunday evening, with roughly a 2
county "buffer" of a winter weather advisory for lesser snowfalls of
2-4 inches for the same time period.   Along and south of
I-70...snowfall totals should be under an inch.  These snowfall
totals include any snowfall from tonight, through Sunday, and into
early Sunday evening.

This is our best estimate of expected snowfall with this storm, and
its important to point out that all indications are that there will
be an extremely tight snowfall gradient from extreme southeast
Iowa into northern MO and west central IL, with snowfall totals
varying greatly over a very short distance. We`ve attempted to
reflect this gradient in the forecast, but in all likelihood the
distance between several inches of snow and just a dusting will be
much tighter than indicated. Any slight change in the expected
gradient will have a very large impact on snowfall totals at any
given location in the warning and advisory areas.

Winds are forecast to increase fairly dramatically in the wake of
the surface low Sunday afternoon and evening over northern parts
of the CWA. Given that much of the snowfall will be quite wet
don`t believe that blowing snow will be much of an issue, but will
be watching out for this threat as some of the accumulating snow
towards the end of the event becomes much drier.

The light snow that lingers into Sunday evening should end no later
than midnight, followed by a cold Canadian high that will drop lows
into the single digits and teens by Monday morning.   00z guidance
supports going forecast trends that temps will remain below normal
on Monday as the high pushes into the mid-Mississippi Valley, and
this will be followed by a fairly strong...but brief...warmup on
Tuesday with highs rebounding into the upper 30s and 40s.

(Wednesday-Friday)

Shortwave rotating through base of broad trof over the CONUS will
usher in another shot of cold air for the last half of the work
week.  By Thursday, highs will only be in the 20s to lower 30s, with
only a modest rebound in temps by Friday. Have continued some
slight chance PoPs with passage of shortwave on Wednesday, with
low PoPs continuing over southern sections of the CWA into
Thursday as GFS suggests this area could be on northern fringes
of system working its way from the southern Plains into the southeast
U.S.

Truett

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 552 AM CST Sat Jan 31 2015

Rain over western and southwestern Missouri to continue developing
and spreading east across forecast area today. VFR cigs to lower
to MVFR/IFR by midday when main area of rain moves into TAF sites.
Otherwise, dealing with south to southwest winds, which will back
to the southeast as warm front associated with system lifts north
through forecast area by this evening. Precipitation to remain as
rain for taf sites along I-70 corridor through forecast period. However,
KUIN to see colder air filter in by 03z Sunday with rain becoming
mixed with snow, then change over to all snow by 09z Sunday.

Specifics for KSTL:
Rain over western and southwestern Missouri to continue developing
and spreading east across forecast area today. VFR cigs to lower
to MVFR by 22z Saturday when main area of rain moves into metro area.
Otherwise, dealing with south to southwest winds, which will back
to the southeast as warm front associated with system lifts north
through forecast area by 01z Sunday. Precipitation to remain as rain for
through forecast period.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Marion MO-Monroe MO-Pike MO-Ralls MO-Shelby MO.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Knox MO-Lewis MO.

IL...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Pike IL.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Adams IL-Brown IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 311543
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
943 AM CST Sat Jan 31 2015

.UPDATE:
Issued at 933 AM CST Sat Jan 31 2015

Brief update to delay onset/lower PoPs across the srn and ern
portions of the CWA. RA continues to move newd into the region.
Expect RA shield to remain along the wrn CWA border over the next
couple of hours, but precip will gradually move ewd/newd impacting
central and nern portions of MO into west central IL. A very brief
period of IP may be possible at the onset of precip. However, as
the onset of precip is delayed, the chances of this occurring are
reduced. Regardless, any IP shud be very brief and not pose an
impact.

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 327 AM CST Sat Jan 31 2015

Mid and high clouds to remain over region ahead of main weather
system. In the meantime, low level moisture and warm air advection
are on the increase on nose of low level jet. So rain will continue
to develop and spread eastward through much of our forecast area
today, especially north and west of St. Louis metro area. It will
mainly be in the form of rain but could see a brief period of snow
mixed in across central and northeast Missouri this morning. As for
high temperatures, they will be in the upper 30s to mid 40s.

Byrd

.LONG TERM:  (Tonight through Friday)
Issued at 327 AM CST Sat Jan 31 2015

(Tonight-Monday)

Obviously, main concern is ptypes and potential snowfall amounts
with storm system pushing into the region.  00z runs have continued
warming trend of low level temp profile in advance of the storm, and
given that this has been the trend for 4 straight model cycles
forecast has been adjusted "warmer" as well.  This adjustment will
manifest itself in a slower transition to all snow, and reduced
snowfall amounts over the central third of the CWA...along the I-70
corridor.

Certainly, best area for accumulations in our CWA will be our far
northern counties, and the key to the forecast is how soon the
precip transitions from rain to snow.  NAM forecast sounding for UIN
indicates some low level cooling that would cause the switch to
occur as early as 03z, while GFS is warmer/slower with cooling.
It`s also interesting, and perhaps a bit worrisome from a heavy
snowfall viewpoint, that both the NAM and GFS are nearly isothermal
at 0C at 12z up to 900mb, and a slight wiggle either warmer or
colder will have a dramatic impact on when the changeover occurs and
ultimately how much snowfall.

Based on this uncertainty have tried to be a bit conservative with
snowfall forecasts across the north, but working the numbers in
various ways still yields snowfall totals of around or just above 6
inches along and north of an Edina-Mount Sterling line, with
snowfall totals dropping off quickly as you head south...to no more
than an inch along a Mexico-Vandalia IL line.  Based on these
forecast amounts, will go with a Winter Storm Warning for our far
northern counties for tonight into Sunday evening, with roughly a 2
county "buffer" of a winter weather advisory for lesser snowfalls of
2-4 inches for the same time period.   Along and south of
I-70...snowfall totals should be under an inch.  These snowfall
totals include any snowfall from tonight, through Sunday, and into
early Sunday evening.

This is our best estimate of expected snowfall with this storm, and
its important to point out that all indications are that there will
be an extremely tight snowfall gradient from extreme southeast
Iowa into northern MO and west central IL, with snowfall totals
varying greatly over a very short distance. We`ve attempted to
reflect this gradient in the forecast, but in all likelihood the
distance between several inches of snow and just a dusting will be
much tighter than indicated. Any slight change in the expected
gradient will have a very large impact on snowfall totals at any
given location in the warning and advisory areas.

Winds are forecast to increase fairly dramatically in the wake of
the surface low Sunday afternoon and evening over northern parts
of the CWA. Given that much of the snowfall will be quite wet
don`t believe that blowing snow will be much of an issue, but will
be watching out for this threat as some of the accumulating snow
towards the end of the event becomes much drier.

The light snow that lingers into Sunday evening should end no later
than midnight, followed by a cold Canadian high that will drop lows
into the single digits and teens by Monday morning.   00z guidance
supports going forecast trends that temps will remain below normal
on Monday as the high pushes into the mid-Mississippi Valley, and
this will be followed by a fairly strong...but brief...warmup on
Tuesday with highs rebounding into the upper 30s and 40s.

(Wednesday-Friday)

Shortwave rotating through base of broad trof over the CONUS will
usher in another shot of cold air for the last half of the work
week.  By Thursday, highs will only be in the 20s to lower 30s, with
only a modest rebound in temps by Friday. Have continued some
slight chance PoPs with passage of shortwave on Wednesday, with
low PoPs continuing over southern sections of the CWA into
Thursday as GFS suggests this area could be on northern fringes
of system working its way from the southern Plains into the southeast
U.S.

Truett

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 552 AM CST Sat Jan 31 2015

Rain over western and southwestern Missouri to continue developing
and spreading east across forecast area today. VFR cigs to lower
to MVFR/IFR by midday when main area of rain moves into TAF sites.
Otherwise, dealing with south to southwest winds, which will back
to the southeast as warm front associated with system lifts north
through forecast area by this evening. Precipitation to remain as
rain for taf sites along I-70 corridor through forecast period. However,
KUIN to see colder air filter in by 03z Sunday with rain becoming
mixed with snow, then change over to all snow by 09z Sunday.

Specifics for KSTL:
Rain over western and southwestern Missouri to continue developing
and spreading east across forecast area today. VFR cigs to lower
to MVFR by 22z Saturday when main area of rain moves into metro area.
Otherwise, dealing with south to southwest winds, which will back
to the southeast as warm front associated with system lifts north
through forecast area by 01z Sunday. Precipitation to remain as rain for
through forecast period.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Marion MO-Monroe MO-Pike MO-Ralls MO-Shelby MO.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Knox MO-Lewis MO.

IL...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Pike IL.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Adams IL-Brown IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 311200
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
600 AM CST Sat Jan 31 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 327 AM CST Sat Jan 31 2015

Mid and high clouds to remain over region ahead of main weather
system. In the meantime, low level moisture and warm air advection
are on the increase on nose of low level jet. So rain will continue
to develop and spread eastward through much of our forecast area
today, especially north and west of St. Louis metro area. It will
mainly be in the form of rain but could see a brief period of snow
mixed in across central and northeast Missouri this morning. As for
high temperatures, they will be in the upper 30s to mid 40s.

Byrd

.LONG TERM:  (Tonight through Friday)
Issued at 327 AM CST Sat Jan 31 2015

(Tonight-Monday)

Obviously, main concern is ptypes and potential snowfall amounts
with storm system pushing into the region.  00z runs have continued
warming trend of low level temp profile in advance of the storm, and
given that this has been the trend for 4 straight model cycles
forecast has been adjusted "warmer" as well.  This adjustment will
manifest itself in a slower transition to all snow, and reduced
snowfall amounts over the central third of the CWA...along the I-70
corridor.

Certainly, best area for accumulations in our CWA will be our far
northern counties, and the key to the forecast is how soon the
precip transitions from rain to snow.  NAM forecast sounding for UIN
indicates some low level cooling that would cause the switch to
occur as early as 03z, while GFS is warmer/slower with cooling.
It`s also interesting, and perhaps a bit worrisome from a heavy
snowfall viewpoint, that both the NAM and GFS are nearly isothermal
at 0C at 12z up to 900mb, and a slight wiggle either warmer or
colder will have a dramatic impact on when the changeover occurs and
ultimately how much snowfall.

Based on this uncertainty have tried to be a bit conservative with
snowfall forecasts across the north, but working the numbers in
various ways still yields snowfall totals of around or just above 6
inches along and north of an Edina-Mount Sterling line, with
snowfall totals dropping off quickly as you head south...to no more
than an inch along a Mexico-Vandalia IL line.  Based on these
forecast amounts, will go with a Winter Storm Warning for our far
northern counties for tonight into Sunday evening, with roughly a 2
county "buffer" of a winter weather advisory for lesser snowfalls of
2-4 inches for the same time period.   Along and south of
I-70...snowfall totals should be under an inch.  These snowfall
totals include any snowfall from tonight, through Sunday, and into
early Sunday evening.

This is our best estimate of expected snowfall with this storm, and
its important to point out that all indications are that there will
be an extremely tight snowfall gradient from extreme southeast
Iowa into northern MO and west central IL, with snowfall totals
varying greatly over a very short distance. We`ve attempted to
reflect this gradient in the forecast, but in all likelihood the
distance between several inches of snow and just a dusting will be
much tighter than indicated. Any slight change in the expected
gradient will have a very large impact on snowfall totals at any
given location in the warning and advisory areas.

Winds are forecast to increase fairly dramatically in the wake of
the surface low Sunday afternoon and evening over northern parts
of the CWA. Given that much of the snowfall will be quite wet
don`t believe that blowing snow will be much of an issue, but will
be watching out for this threat as some of the accumulating snow
towards the end of the event becomes much drier.

The light snow that lingers into Sunday evening should end no later
than midnight, followed by a cold Canadian high that will drop lows
into the single digits and teens by Monday morning.   00z guidance
supports going forecast trends that temps will remain below normal
on Monday as the high pushes into the mid-Mississippi Valley, and
this will be followed by a fairly strong...but brief...warmup on
Tuesday with highs rebounding into the upper 30s and 40s.

(Wednesday-Friday)

Shortwave rotating through base of broad trof over the CONUS will
usher in another shot of cold air for the last half of the work
week.  By Thursday, highs will only be in the 20s to lower 30s, with
only a modest rebound in temps by Friday. Have continued some
slight chance PoPs with passage of shortwave on Wednesday, with
low PoPs continuing over southern sections of the CWA into
Thursday as GFS suggests this area could be on northern fringes
of system working its way from the southern Plains into the southeast
U.S.

Truett

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 552 AM CST Sat Jan 31 2015

Rain over western and southwestern Missouri to continue developing
and spreading east across forecast area today. VFR cigs to lower
to MVFR/IFR by midday when main area of rain moves into TAF sites.
Otherwise, dealing with south to southwest winds, which will back
to the southeast as warm front associated with system lifts north
through forecast area by this evening. Precipitation to remain as
rain for taf sites along I-70 corridor through forecast period. However,
KUIN to see colder air filter in by 03z Sunday with rain becoming
mixed with snow, then change over to all snow by 09z Sunday.

Specifics for KSTL:
Rain over western and southwestern Missouri to continue developing
and spreading east across forecast area today. VFR cigs to lower
to MVFR by 22z Saturday when main area of rain moves into metro area.
Otherwise, dealing with south to southwest winds, which will back
to the southeast as warm front associated with system lifts north
through forecast area by 01z Sunday. Precipitation to remain as rain for
through forecast period.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Marion MO-Monroe MO-Pike MO-Ralls MO-Shelby MO.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Knox MO-Lewis MO.

IL...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Pike IL.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Adams IL-Brown IL.

&&

$$
WFO LSX






000
FXUS63 KLSX 310941
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
341 AM CST Sat Jan 31 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 327 AM CST Sat Jan 31 2015

Mid and high clouds to remain over region ahead of main weather
system. In the meantime, low level moisture and warm air advection
are on the increase on nose of low level jet. So rain will continue
to develop and spread eastward through much of our forecast area
today, especially north and west of St. Louis metro area. It will
mainly be in the form of rain but could see a brief period of snow
mixed in across central and northeast Missouri this morning. As for
high temperatures, they will be in the upper 30s to mid 40s.

Byrd

.LONG TERM:  (Tonight through Friday)
Issued at 327 AM CST Sat Jan 31 2015

(Tonight-Monday)

Obivously, main concern is ptypes and potential snowfall amounts
with storm system pushing into the region.  00z runs have continued
warming trend of low level temp profile in advance of the storm, and
given that this has been the trend for 4 straight model cycles
forecast has been adjusted "warmer" as well.  This adjustment will
manifest itself in a slower transition to all snow, and reduced
snowfall amounts over the central third of the CWA...along the I-70
corridor.

Certainly, best area for accumulations in our CWA will be our far
northern counties, and the key to the forecast is how soon the
precip transitions from rain to snow.  NAM forecast sounding for UIN
indicates some low level cooling that would cause the switch to
occur as early as 03z, while GFS is warmer/slower with cooling.
It`s also interesting, and perhaps a bit worrisome from a heavy
snowfall viewpoint, that both the NAM and GFS are nearly isothermal
at 0C at 12z up to 900mb, and a slight wiggle either warmer or
colder will have a dramatic impact on when the changeover occurs and
ultimately how much snowfall.

Based on this uncertainty have tried to be a bit conservative with
snowfall forecasts across the north, but working the numbers in
various ways still yields snowfall totals of around or just above 6
inches along and north of an Edina-Mount Sterling line, with
snowfall totals dropping off quickly as you head south...to no more
than an inch along a Mexico-Vandalia IL line.  Based on these
forecast amounts, will go with a Winter Storm Warning for our far
northern counties for tonight into Sunday evening, with roughly a 2
county "buffer" of a winter weather advisory for lesser snowfalls of
2-4 inches for the same time period.   Along and south of
I-70...snowfall totals should be under an inch.  These snowfall
totals include any snowfall from tonight, through Sunday, and into
early Sunday evening.

This is our best estimate of expected snowfall with this storm, and
its important to point out that all indications are that there will
be an extremely tight snowfall gradient from extreme southeast
Iowa into northern MO and west central IL, with snowfall totals
varying greatly over a very short distance. We`ve attempted to
reflect this gradient in the forecast, but in all likelihood the
distance between several inches of snow and just a dusting will be
much tighter than indicated. Any slight change in the expected
gradient will have a very large impact on snowfall totals at any
given location in the warning and advisory areas.

Winds are forecast to increase fairly dramatically in the wake of
the surface low sunday afternoon and evening over northern parts
of the CWA. Given that much of the snowfall will be quite wet
don`t believe that blowing snow will be much of an issue, but will
be watching out for this threat as some of the accumulating snow
towards the end of the event becomes much drier.

The light snow that lingers into Sunday evening should end no later
than midnight, followed by a cold Canadian high that will drop lows
into the single digits and teens by Monday morning.   00z guidance
supports going forecast trends that temps will remain below normal
on Monday as the high pushes into the mid-Mississippi Valley, and
this will be followed by a fairly strong...but brief...warmup on
Tuesday with highs rebounding into the upper 30s and 40s.

(Wednesday-Friday)

Shortwave rotating through base of broad trof over the CONUS will
usher in another shot of cold air for the last half of the work
week.  By Thursday, highs will only be in the 20s to lower 30s, with
only a modest rebound in temps by Friday. Have continued some
slight chance PoPs with passage of shortwave on Wednesday, with
low PoPs continuing over southern sections of the CWA into
Thursday as GFS suggests this area could be on northern fringes
of system working its way from the southern Plains into the southeast
U.S.

Truett

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1127 PM CST Fri Jan 30 2015

Specifics for KUIN, KCOU: VFR for at least the first 0-6 hours and
possibly longer. Clouds will lower and thicken ahead of an
approaching low pressure system. Regional radar loops and METARS
show that rain is spreading eastward across the region and should
begin at KCOU during the morning and then at KUIN during the
afternoon hours. KUIN is far enough north that the earlier arrival
of colder air at the terminal would mean a longer duration of
snowfall, and several inches of snow could accumulate at KUIN between
Saturday night and Sunday night. At this time, only minor snowfall
accumulations are expected at KCOU, and the transition from rain
to snow is beyond the end of the valid TAF period.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-6 hours
and probably through the first 12 hours. Clouds will lower and
thicken ahead of an approaching low pressure system. A prolonged
period of rain is expected on Saturday. When colder air arrives,
it might cause the rain to mix with or change to snow very late on
Saturday night into Sunday.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Marion MO-Monroe MO-Pike MO-Ralls MO-Shelby MO.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Knox MO-Lewis MO.

IL...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Pike IL.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Adams IL-Brown IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 310941
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
341 AM CST Sat Jan 31 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 327 AM CST Sat Jan 31 2015

Mid and high clouds to remain over region ahead of main weather
system. In the meantime, low level moisture and warm air advection
are on the increase on nose of low level jet. So rain will continue
to develop and spread eastward through much of our forecast area
today, especially north and west of St. Louis metro area. It will
mainly be in the form of rain but could see a brief period of snow
mixed in across central and northeast Missouri this morning. As for
high temperatures, they will be in the upper 30s to mid 40s.

Byrd

.LONG TERM:  (Tonight through Friday)
Issued at 327 AM CST Sat Jan 31 2015

(Tonight-Monday)

Obivously, main concern is ptypes and potential snowfall amounts
with storm system pushing into the region.  00z runs have continued
warming trend of low level temp profile in advance of the storm, and
given that this has been the trend for 4 straight model cycles
forecast has been adjusted "warmer" as well.  This adjustment will
manifest itself in a slower transition to all snow, and reduced
snowfall amounts over the central third of the CWA...along the I-70
corridor.

Certainly, best area for accumulations in our CWA will be our far
northern counties, and the key to the forecast is how soon the
precip transitions from rain to snow.  NAM forecast sounding for UIN
indicates some low level cooling that would cause the switch to
occur as early as 03z, while GFS is warmer/slower with cooling.
It`s also interesting, and perhaps a bit worrisome from a heavy
snowfall viewpoint, that both the NAM and GFS are nearly isothermal
at 0C at 12z up to 900mb, and a slight wiggle either warmer or
colder will have a dramatic impact on when the changeover occurs and
ultimately how much snowfall.

Based on this uncertainty have tried to be a bit conservative with
snowfall forecasts across the north, but working the numbers in
various ways still yields snowfall totals of around or just above 6
inches along and north of an Edina-Mount Sterling line, with
snowfall totals dropping off quickly as you head south...to no more
than an inch along a Mexico-Vandalia IL line.  Based on these
forecast amounts, will go with a Winter Storm Warning for our far
northern counties for tonight into Sunday evening, with roughly a 2
county "buffer" of a winter weather advisory for lesser snowfalls of
2-4 inches for the same time period.   Along and south of
I-70...snowfall totals should be under an inch.  These snowfall
totals include any snowfall from tonight, through Sunday, and into
early Sunday evening.

This is our best estimate of expected snowfall with this storm, and
its important to point out that all indications are that there will
be an extremely tight snowfall gradient from extreme southeast
Iowa into northern MO and west central IL, with snowfall totals
varying greatly over a very short distance. We`ve attempted to
reflect this gradient in the forecast, but in all likelihood the
distance between several inches of snow and just a dusting will be
much tighter than indicated. Any slight change in the expected
gradient will have a very large impact on snowfall totals at any
given location in the warning and advisory areas.

Winds are forecast to increase fairly dramatically in the wake of
the surface low sunday afternoon and evening over northern parts
of the CWA. Given that much of the snowfall will be quite wet
don`t believe that blowing snow will be much of an issue, but will
be watching out for this threat as some of the accumulating snow
towards the end of the event becomes much drier.

The light snow that lingers into Sunday evening should end no later
than midnight, followed by a cold Canadian high that will drop lows
into the single digits and teens by Monday morning.   00z guidance
supports going forecast trends that temps will remain below normal
on Monday as the high pushes into the mid-Mississippi Valley, and
this will be followed by a fairly strong...but brief...warmup on
Tuesday with highs rebounding into the upper 30s and 40s.

(Wednesday-Friday)

Shortwave rotating through base of broad trof over the CONUS will
usher in another shot of cold air for the last half of the work
week.  By Thursday, highs will only be in the 20s to lower 30s, with
only a modest rebound in temps by Friday. Have continued some
slight chance PoPs with passage of shortwave on Wednesday, with
low PoPs continuing over southern sections of the CWA into
Thursday as GFS suggests this area could be on northern fringes
of system working its way from the southern Plains into the southeast
U.S.

Truett

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1127 PM CST Fri Jan 30 2015

Specifics for KUIN, KCOU: VFR for at least the first 0-6 hours and
possibly longer. Clouds will lower and thicken ahead of an
approaching low pressure system. Regional radar loops and METARS
show that rain is spreading eastward across the region and should
begin at KCOU during the morning and then at KUIN during the
afternoon hours. KUIN is far enough north that the earlier arrival
of colder air at the terminal would mean a longer duration of
snowfall, and several inches of snow could accumulate at KUIN between
Saturday night and Sunday night. At this time, only minor snowfall
accumulations are expected at KCOU, and the transition from rain
to snow is beyond the end of the valid TAF period.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-6 hours
and probably through the first 12 hours. Clouds will lower and
thicken ahead of an approaching low pressure system. A prolonged
period of rain is expected on Saturday. When colder air arrives,
it might cause the rain to mix with or change to snow very late on
Saturday night into Sunday.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Marion MO-Monroe MO-Pike MO-Ralls MO-Shelby MO.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Knox MO-Lewis MO.

IL...WINTER WEATHER ADVISORY from 9 PM this evening to 9 PM CST
     Sunday FOR Pike IL.

     WINTER STORM WARNING from 9 PM this evening to 9 PM CST Sunday
     FOR Adams IL-Brown IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 310536
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1136 PM CST Fri Jan 30 2015

.UPDATE:
Issued at 923 PM CST Fri Jan 30 2015

Main concern for late tonight and early Saturday is onset of
precipitation and ptype across central/northeast Missouri. Global
models...along with RAP/HRRR suggest a band of frontogentically
enhanced precip oriented WNW-ESE will advect into portions of
central and northeast Missouri by 1500 UTC. Have therefore boosted
PoPs into the mid chance category for early Saturday morning.
Precipitation type looks to be a challenge however as low-level
warm advection and bump in temps overnight from increasing cloud
cover battle the wetbulbing/evaporative cooling after
precipitation begins. Generally left sfc temperatures and
therefore wx grids alone which leaves a rain/snow possible early
Saturday morning before sfc warming yields a changeover to rain.
Also cannot rule out some sleet...though did not explicitly
mention at this time...due to very dry low levels as per KSGF/KTOP
0000 UTC soundings.

Gosselin

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1127 PM CST Fri Jan 30 2015

Specifics for KUIN, KCOU: VFR for at least the first 0-6 hours and
possibly longer. Clouds will lower and thicken ahead of an
approaching low pressure system. Regional radar loops and METARS
show that rain is spreading eastward across the region and should
begin at KCOU during the morning and then at KUIN during the
afternoon hours. KUIN is far enough north that the earlier arrival
of colder air at the terminal would mean a longer duration of
snowfall, and several inches of snow could accumulate at KUIN between
Saturday night and Sunday night. At this time, only minor snowfall
accumulations are expected at KCOU, and the transition from rain
to snow is beyond the end of the valid TAF period.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-6 hours
and probably through the first 12 hours. Clouds will lower and
thicken ahead of an approaching low pressure system. A prolonged
period of rain is expected on Saturday. When colder air arrives,
it might cause the rain to mix with or change to snow very late on
Saturday night into Sunday.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 310536
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1136 PM CST Fri Jan 30 2015

.UPDATE:
Issued at 923 PM CST Fri Jan 30 2015

Main concern for late tonight and early Saturday is onset of
precipitation and ptype across central/northeast Missouri. Global
models...along with RAP/HRRR suggest a band of frontogentically
enhanced precip oriented WNW-ESE will advect into portions of
central and northeast Missouri by 1500 UTC. Have therefore boosted
PoPs into the mid chance category for early Saturday morning.
Precipitation type looks to be a challenge however as low-level
warm advection and bump in temps overnight from increasing cloud
cover battle the wetbulbing/evaporative cooling after
precipitation begins. Generally left sfc temperatures and
therefore wx grids alone which leaves a rain/snow possible early
Saturday morning before sfc warming yields a changeover to rain.
Also cannot rule out some sleet...though did not explicitly
mention at this time...due to very dry low levels as per KSGF/KTOP
0000 UTC soundings.

Gosselin

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1127 PM CST Fri Jan 30 2015

Specifics for KUIN, KCOU: VFR for at least the first 0-6 hours and
possibly longer. Clouds will lower and thicken ahead of an
approaching low pressure system. Regional radar loops and METARS
show that rain is spreading eastward across the region and should
begin at KCOU during the morning and then at KUIN during the
afternoon hours. KUIN is far enough north that the earlier arrival
of colder air at the terminal would mean a longer duration of
snowfall, and several inches of snow could accumulate at KUIN between
Saturday night and Sunday night. At this time, only minor snowfall
accumulations are expected at KCOU, and the transition from rain
to snow is beyond the end of the valid TAF period.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-6 hours
and probably through the first 12 hours. Clouds will lower and
thicken ahead of an approaching low pressure system. A prolonged
period of rain is expected on Saturday. When colder air arrives,
it might cause the rain to mix with or change to snow very late on
Saturday night into Sunday.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 310346
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
946 PM CST Fri Jan 30 2015

.UPDATE:
Issued at 923 PM CST Fri Jan 30 2015

Main concern for late tonight and early Saturday is onset of
precipitation and ptype across central/northeast Missouri. Global
models...along with RAP/HRRR suggest a band of frontogentically
enhanced precip oriented WNW-ESE will advect into portions of
central and northeast Missouri by 1500 UTC. Have therefore boosted
PoPs into the mid chance category for early Saturday morning.
Precipitation type looks to be a challenge however as low-level
warm advection and bump in temps overnight from increasing cloud
cover battle the wetbulbing/evaporative cooling after
precipitation begins. Generally left sfc temperatures and
therefore wx grids alone which leaves a rain/snow possible early
Saturday morning before sfc warming yields a changeover to rain.
Also cannot rule out some sleet...though did not explicity mention
at this time...due to very dry low levels as per KSGF/KTOP 0000
UTC soundings.

Gosselin

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Saturday Evening)
Issued at 513 PM CST Fri Jan 30 2015

VFR for at least the first 0-6 hours and probably up to the first
12 hours. Clouds will lower and thicken ahead of an approaching
low pressure system. Light rain is expected to begin tomorrow
morning at KCOU, eventually spreading to the rest of the TAF
sites. Beyond the end of the valid TAF period, the rain will start
to mix with and change over to snow. There is low confidence
regarding the timing of the onset of rain and its eventual
changeover to snow.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-12
hours. Clouds will start to lower and thicken tomorrow ahead of an
approaching low pressure system. Light rain is expected to begin
tomorrow afternoon and then mix with or change over to snow beyond
the end of the valid TAF period. There is low confidence regarding
the timing of the onset of rain and its eventual changeover to
snow.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 302321
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
521 PM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Saturday Evening)
Issued at 513 PM CST Fri Jan 30 2015

VFR for at least the first 0-6 hours and probably up to the first
12 hours. Clouds will lower and thicken ahead of an approaching
low pressure system. Light rain is expected to begin tomorrow
morning at KCOU, eventually spreading to the rest of the TAF
sites. Beyond the end of the valid TAF period, the rain will start
to mix with and change over to snow. There is low confidence
regarding the timing of the onset of rain and its eventual
changeover to snow.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-12
hours. Clouds will start to lower and thicken tomorrow ahead of an
approaching low pressure system. Light rain is expected to begin
tomorrow afternoon and then mix with or change over to snow beyond
the end of the valid TAF period. There is low confidence regarding
the timing of the onset of rain and its eventual changeover to
snow.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 302321
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
521 PM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Saturday Evening)
Issued at 513 PM CST Fri Jan 30 2015

VFR for at least the first 0-6 hours and probably up to the first
12 hours. Clouds will lower and thicken ahead of an approaching
low pressure system. Light rain is expected to begin tomorrow
morning at KCOU, eventually spreading to the rest of the TAF
sites. Beyond the end of the valid TAF period, the rain will start
to mix with and change over to snow. There is low confidence
regarding the timing of the onset of rain and its eventual
changeover to snow.

Specifics for KSTL, KSUS, KCPS: VFR for at least the first 0-12
hours. Clouds will start to lower and thicken tomorrow ahead of an
approaching low pressure system. Light rain is expected to begin
tomorrow afternoon and then mix with or change over to snow beyond
the end of the valid TAF period. There is low confidence regarding
the timing of the onset of rain and its eventual changeover to
snow.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 302129
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
329 PM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1114 AM CST Fri Jan 30 2015

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase across the region this
afternoon and tonight as a large surface high slowly retreats
eastward. Mid and eventually lower clouds will begin spreading
into the area on Saturday morning. The onset of precipitation with
the next storm system is a bit tricky in timing. At most
terminals the onset will be after the valid TAF forecast period,
however light rain will probably develop at KCOU between 15-18z
Sat 31 Jan.

Specifics for KSTL:

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase this afternoon and tonight as
a large surface high slowly retreats eastward. Mid clouds will
begin spreading into the area on Saturday morning with lower clouds
on Saturday afternoon. The onset of precipitation with the next
storm system is a bit tricky, but current thoughts are light rain
will probably develop at KSTL around 21z Sat 31 Jan.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 302129
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
329 PM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 328 PM CST Fri Jan 30 2015

Tranquil weather and seasonably cold weather conditions expected
tonight.  Extensive high clouds currently located across the Plains
in advance of the western U.S. trof are filtering into the area this
afternoon. These clouds will continue to increase and thicken
tonight while the surface high currently centered through the CWA
slowly retreats eastward.

Glass

.LONG TERM:  (Saturday through Next Friday)
Issued at 328 PM CST Fri Jan 30 2015

Clouds along with rain will spread eastward through much of our
forecast area, particularly north and west of STL on Saturday as a
southwesterly low level jet brings increasing low level warm air
advection and moisture into our ahead ahead of an approaching storm
system.  It appears that the precipitation type will be mainly
liquid rain on Saturday, although there is a possibility of a brief
period of snow/sleet across northeast and central MO if the
precipitation makes it into this area already by early to mid
morning when the surface layer will still be quite cold.  There will
also be some evaporational cooling at the onset of the precipitation
as well.  Precipitation should spread throughout the entire forecast
area Saturday night and intensify with the approach of a strong
northern stream shortwave and as a surface low develops over
southwestern MO.  The models also depict upper level divergence,
particularly across northeast MO and west central IL in the right
entrance region of an upper level jet streak over the Great Lakes
region.  The rain will gradually change over to snow, mainly across
northeast MO and west central IL Saturday night as a cold front sags
southward into this area and pseudo adiabatic cooling increases due
to stronger upward vertical motion.  The surface low will track
eastward through southern portions of MO and IL on Sunday, while the
850 mb low moves eastward through northern MO and central IL.  The
precipitation will continue on Sunday with a gradual changeover to
snow across most of the rest of the forecast area as colder air
filters into the region behind the surface/850 mb low and causes the
freezing level to drop.  Surface temperatures across much of our
area late Sunday morning and afternoon may be nearly steady or
slowly fall.  The latest model runs have trended further north
with the storm system and are now slower with the change over to
snow across central and southeast MO as well as southwest IL.  This
will lead to less snow accumulation across this area, but am still
expecting significant snowfall across northeast MO and west central
IL where the greatest forcing is expected along with the quickest
changeover to snow.  Although it is still a little early to pin down
exact snowfall totals as the models continue to vary from run to
run, but preliminary forecasted amounts will range from 6 to 8
inches across parts of northeast MO and west central IL down to
around 1 to 3 inches across parts of central MO and southwest IL to
less than 1 inch further south over southeast MO.  With forecasted
snowfall totals reaching and slightly exceeding 6 inches over the
extreme northern portion of our forecast area will issue a winter
storm watch for this area for Saturday night and Sunday.  There may
be some lingering light snow in the deformation zone mainly across
northeast MO and west central into southwest IL Sunday evening, but
it should be tapering off with time Sunday night.  Strong and gusty
winds may produce some blowing and drifting snow across the northern
portion of our forecast area Sunday afternoon and evening.  Much
colder temperatures are expected Sunday night behind the storm
system as the models drop the -12 degree C 850 mb isotherm south of
STL Sunday night.

A cold day is on tap for Monday with below normal temperatures as a
large surface high settles into the area in the wake of the
departing vigorous upper trof and attendant cold front. The flow
aloft then becomes broadly cyclonic after this vigorous upper trof
departs the region and this will allow for several lower amplitude
disturbances to traverse the area within the flow aloft, one of
which will bring a cold front midweek. We should see a brief
moderation in temperatures Tuesday into early Wednesday with the
next strong cold front pushing through the region during the day
Wednesday. I am not expecting much if anything in the way of
precipitation but there is some post-frontal frontogenetical forcing
that is worthy of a low pop. Cold weather with below average
temperatures will prevail through the week`s end as high pressure
dominates.

GKS/Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1114 AM CST Fri Jan 30 2015

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase across the region this
afternoon and tonight as a large surface high slowly retreats
eastward. Mid and eventually lower clouds will begin spreading
into the area on Saturday morning. The onset of precipitation with
the next storm system is a bit tricky in timing. At most
terminals the onset will be after the valid TAF forecast period,
however light rain will probably develop at KCOU between 15-18z
Sat 31 Jan.

Specifics for KSTL:

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase this afternoon and tonight as
a large surface high slowly retreats eastward. Mid clouds will
begin spreading into the area on Saturday morning with lower clouds
on Saturday afternoon. The onset of precipitation with the next
storm system is a bit tricky, but current thoughts are light rain
will probably develop at KSTL around 21z Sat 31 Jan.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 301721
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1121 AM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CST Fri Jan 30 2015

Surface ridge to build over region today with sc deck along and east
of Mississippi River slowly clearing out. Despite plenty of sunshine
most of the day today, temperatures will remain near normal in the
mid 30s to low 40s.

Byrd

.LONG TERM:  (Tonight through Thursday)
Issued at 354 AM CST Fri Jan 30 2015

(Tonight-Monday)

Primary concern in the short range continues to be potential for
wintry conditions Saturday-Sunday.  00z guidance has come in a bit
warmer than earlier solutions with regards to ptype, so have
judiciously trended the forecast a bit warmer...and to a slower
changeover to snow.

Precip with upcoming system should be tied to two different
features...first, the WAA in advance of the system, and secondly
some wrap around precip on Sunday as secondary shortwave drops into
the mid-Mississippi Valley in the wake of the main system.  This
secondary shortwave will likely produce some measurable snow on
Sunday...especially over the northeast half of the CWA.   However,
the key to total snowfalls with this storm will likely be tied to
how quickly the WAA precip can transition from liquid to frozen on
Saturday night/early Sunday. I`ve been a bit aggressive in the
changeover in our far north overnight Saturday night, and when you
combine this changeover to the lighter precip that should be all
snow on Sunday snowfall totals are calculated in the 5-6 inch range
over our northern counties.  This may be a bit high considering the
850mb low track is directly over our northern counties, but if
precip can change over fast enough these numbers should be in the
ball park. Snowfall totals should then drop off as you head south,
with 1-3 inches along the I-70 corridor.  In our far southern
counties persistent low level WAA should cause the changeover to all
snow to be a struggle, so snowfall totals here should be under an
inch.

Snowfall forecasts will continue to evolve over the next 24 hours as
we try to fine-tune low level thermal profiles.  Obviously, if the
changeover to snow in the WAA band is delayed these amounts will
need to be adjusted down, but as mentioned above even if this
changeover is significantly delayed Saturday night, some measurable
snow should still be expected over northeast sections of the CWA on
Sunday.

Snow should taper off early Sunday evening, with Canadian high
bringing another round of cold air and below normal temperatures
to the region Sunday night and Monday.

(Tuesday-Thursday)

Temperatures should briefly moderate on Tuesday, followed by more
cold air and below normal temperatures for the Wednesday-Thursday
time frame. Forecasts will carry some low, slight chance PoPs
Wednesday-Thursday...tied to the next frontal passage.

Truett

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1114 AM CST Fri Jan 30 2015

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase across the region this
afternoon and tonight as a large surface high slowly retreats
eastward. Mid and eventually lower clouds will begin spreading
into the area on Saturday morning. The onset of precipitation with
the next storm system is a bit tricky in timing. At most
terminals the onset will be after the valid TAF forecast period,
however light rain will probably develop at KCOU between 15-18z
Sat 31 Jan.

Specifics for KSTL:

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase this afternoon and tonight as
a large surface high slowly retreats eastward. Mid clouds will
begin spreading into the area on Saturday morning with lower clouds
on Saturday afternoon. The onset of precipitation with the next
storm system is a bit tricky, but current thoughts are light rain
will probably develop at KSTL around 21z Sat 31 Jan.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 301721
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1121 AM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CST Fri Jan 30 2015

Surface ridge to build over region today with sc deck along and east
of Mississippi River slowly clearing out. Despite plenty of sunshine
most of the day today, temperatures will remain near normal in the
mid 30s to low 40s.

Byrd

.LONG TERM:  (Tonight through Thursday)
Issued at 354 AM CST Fri Jan 30 2015

(Tonight-Monday)

Primary concern in the short range continues to be potential for
wintry conditions Saturday-Sunday.  00z guidance has come in a bit
warmer than earlier solutions with regards to ptype, so have
judiciously trended the forecast a bit warmer...and to a slower
changeover to snow.

Precip with upcoming system should be tied to two different
features...first, the WAA in advance of the system, and secondly
some wrap around precip on Sunday as secondary shortwave drops into
the mid-Mississippi Valley in the wake of the main system.  This
secondary shortwave will likely produce some measurable snow on
Sunday...especially over the northeast half of the CWA.   However,
the key to total snowfalls with this storm will likely be tied to
how quickly the WAA precip can transition from liquid to frozen on
Saturday night/early Sunday. I`ve been a bit aggressive in the
changeover in our far north overnight Saturday night, and when you
combine this changeover to the lighter precip that should be all
snow on Sunday snowfall totals are calculated in the 5-6 inch range
over our northern counties.  This may be a bit high considering the
850mb low track is directly over our northern counties, but if
precip can change over fast enough these numbers should be in the
ball park. Snowfall totals should then drop off as you head south,
with 1-3 inches along the I-70 corridor.  In our far southern
counties persistent low level WAA should cause the changeover to all
snow to be a struggle, so snowfall totals here should be under an
inch.

Snowfall forecasts will continue to evolve over the next 24 hours as
we try to fine-tune low level thermal profiles.  Obviously, if the
changeover to snow in the WAA band is delayed these amounts will
need to be adjusted down, but as mentioned above even if this
changeover is significantly delayed Saturday night, some measurable
snow should still be expected over northeast sections of the CWA on
Sunday.

Snow should taper off early Sunday evening, with Canadian high
bringing another round of cold air and below normal temperatures
to the region Sunday night and Monday.

(Tuesday-Thursday)

Temperatures should briefly moderate on Tuesday, followed by more
cold air and below normal temperatures for the Wednesday-Thursday
time frame. Forecasts will carry some low, slight chance PoPs
Wednesday-Thursday...tied to the next frontal passage.

Truett

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1114 AM CST Fri Jan 30 2015

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase across the region this
afternoon and tonight as a large surface high slowly retreats
eastward. Mid and eventually lower clouds will begin spreading
into the area on Saturday morning. The onset of precipitation with
the next storm system is a bit tricky in timing. At most
terminals the onset will be after the valid TAF forecast period,
however light rain will probably develop at KCOU between 15-18z
Sat 31 Jan.

Specifics for KSTL:

VFR flight conditions will prevail for the valid forecast period.
High clouds will steadily increase this afternoon and tonight as
a large surface high slowly retreats eastward. Mid clouds will
begin spreading into the area on Saturday morning with lower clouds
on Saturday afternoon. The onset of precipitation with the next
storm system is a bit tricky, but current thoughts are light rain
will probably develop at KSTL around 21z Sat 31 Jan.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Knox MO-Lewis MO-Marion MO-Shelby MO.

IL...WINTER STORM WATCH from Saturday evening through Sunday
     afternoon FOR Adams IL-Brown IL-Pike IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 301143
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
543 AM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CST Fri Jan 30 2015

Surface ridge to build over region today with sc deck along and east
of Mississippi River slowly clearing out. Despite plenty of sunshine
most of the day today, temperatures will remain near normal in the
mid 30s to low 40s.

Byrd

.LONG TERM:  (Tonight through Thursday)
Issued at 354 AM CST Fri Jan 30 2015

(Tonight-Monday)

Primary concern in the short range continues to be potential for
wintry conditions Saturday-Sunday.  00z guidance has come in a bit
warmer than earlier solutions with regards to ptype, so have
judiciously trended the forecast a bit warmer...and to a slower
changeover to snow.

Precip with upcoming system should be tied to two different
features...first, the WAA in advance of the system, and secondly
some wrap around precip on Sunday as secondary shortwave drops into
the mid-Mississippi Valley in the wake of the main system.  This
secondary shortwave will likely produce some measurable snow on
Sunday...especially over the northeast half of the CWA.   However,
the key to total snowfalls with this storm will likely be tied to
how quickly the WAA precip can transition from liquid to frozen on
Saturday night/early Sunday. I`ve been a bit aggressive in the
changeover in our far north overnight Saturday night, and when you
combine this changeover to the lighter precip that should be all
snow on Sunday snowfall totals are calculated in the 5-6 inch range
over our northern counties.  This may be a bit high considering the
850mb low track is directly over our northern counties, but if
precip can change over fast enough these numbers should be in the
ball park. Snowfall totals should then drop off as you head south,
with 1-3 inches along the I-70 corridor.  In our far southern
counties persistent low level WAA should cause the changeover to all
snow to be a struggle, so snowfall totals here should be under an
inch.

Snowfall forecasts will continue to evolve over the next 24 hours as
we try to fine-tune low level thermal profiles.  Obviously, if the
changeover to snow in the WAA band is delayed these amounts will
need to be adjusted down, but as mentioned above even if this
changeover is significantly delayed Saturday night, some measurable
snow should still be expected over northeast sections of the CWA on
Sunday.

Snow should taper off early Sunday evening, with Canadian high
bringing another round of cold air and below normal temperatures
to the region Sunday night and Monday.

(Tuesday-Thursday)

Temperatures should briefly moderate on Tuesday, followed by more
cold air and below normal temperatures for the Wednesday-Thursday
time frame. Forecasts will carry some low, slight chance PoPs
Wednesday-Thursday...tied to the next frontal passage.

Truett
&&

.AVIATION:  (For the 12z TAFs through 12z Saturday Morning)
Issued at 537 AM CST Fri Jan 30 2015

Surface ridge to build in over region today with sc deck to
scatter out at all taf sites by 14z. Otherwise, north winds to
become light and variable. Then surface ridge to move off to the
east late tonight with winds becoming southerly.

Specifics for KSTL:
Surface ridge to build in over region today with sc deck to
scatter out at all taf sites by 14z. Otherwise, north winds to
become light and variable. Then surface ridge to move off to the
east late tonight with winds becoming southerly.

Byrd
&&

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

$$
WFO LSX







000
FXUS63 KLSX 300956
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
356 AM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CST Fri Jan 30 2015

Surface ridge to build over region today with sc deck along and east
of Mississippi River slowly clearing out. Despite plenty of sunshine
most of the day today, temperatures will remain near normal in the
mid 30s to low 40s.

Byrd

.LONG TERM:  (Tonight through Thursday)
Issued at 354 AM CST Fri Jan 30 2015

(Tonight-Monday)

Primary concern in the short range continues to be potential for
wintry conditions Saturday-Sunday.  00z guidance has come in a bit
warmer than earlier solutions with regards to ptype, so have
judiciously trended the forecast a bit warmer...and to a slower
changeover to snow.

Precip with upcoming system should be tied to two different
features...first, the WAA in advance of the system, and secondly
some wrap around precip on Sunday as secondary shortwave drops into
the mid-Mississippi Valley in the wake of the main system.  This
secondary shortwave will likely produce some measurable snow on
Sunday...especially over the northeast half of the CWA.   However,
the key to total snowfalls with this storm will likely be tied to
how quickly the WAA precip can transition from liquid to frozen on
Saturday night/early Sunday. I`ve been a bit aggressive in the
changeover in our far north overnight Saturday night, and when you
combine this changeover to the lighter precip that should be all
snow on Sunday snowfall totals are calculated in the 5-6 inch range
over our northern counties.  This may be a bit high considering the
850mb low track is directly over our northern counties, but if
precip can change over fast enough these numbers should be in the
ball park. Snowfall totals should then drop off as you head south,
with 1-3 inches along the I-70 corridor.  In our far southern
counties persistent low level WAA should cause the changeover to all
snow to be a struggle, so snowfall totals here should be under an
inch.

Snowfall forecasts will continue to evolve over the next 24 hours as
we try to fine-tune low level thermal profiles.  Obviously, if the
changeover to snow in the WAA band is delayed these amounts will
need to be adjusted down, but as mentioned above even if this
changeover is significantly delayed Saturday night, some measurable
snow should still be expected over northeast sections of the CWA on
Sunday.

Snow should taper off early Sunday evening, with Canadian high
bringing another round of cold air and below normal temperatures
to the region Sunday night and Monday.

(Tuesday-Thursday)

Temperatures should briefly moderate on Tuesday, followed by more
cold air and below normal temperatures for the Wednesday-Thursday
time frame. Forecasts will carry some low, slight chance PoPs
Wednesday-Thursday...tied to the next frontal passage.

Truett

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1139 PM CST Thu Jan 29 2015

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. KCOU has already scattered out as of 0530 UTC.
Further east...expect KUIN and metro TAF sites to remain
predominantly broken with periodic scattering through late
tonight. VFR conditions are expected thereafter with NNW winds
lightening up and becoming variable by afternoon as sfc high
approaches region.


Specifics for KSTL:

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. Further east...expect Lambert Field to remain
predominantly broken with periodic scattering through late
tonight/early Friday morning. VFR conditions are expected thereafter
with NNW winds lightening up and becoming variable by afternoon as
sfc high approaches region.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 300956
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
356 AM CST Fri Jan 30 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 354 AM CST Fri Jan 30 2015

Surface ridge to build over region today with sc deck along and east
of Mississippi River slowly clearing out. Despite plenty of sunshine
most of the day today, temperatures will remain near normal in the
mid 30s to low 40s.

Byrd

.LONG TERM:  (Tonight through Thursday)
Issued at 354 AM CST Fri Jan 30 2015

(Tonight-Monday)

Primary concern in the short range continues to be potential for
wintry conditions Saturday-Sunday.  00z guidance has come in a bit
warmer than earlier solutions with regards to ptype, so have
judiciously trended the forecast a bit warmer...and to a slower
changeover to snow.

Precip with upcoming system should be tied to two different
features...first, the WAA in advance of the system, and secondly
some wrap around precip on Sunday as secondary shortwave drops into
the mid-Mississippi Valley in the wake of the main system.  This
secondary shortwave will likely produce some measurable snow on
Sunday...especially over the northeast half of the CWA.   However,
the key to total snowfalls with this storm will likely be tied to
how quickly the WAA precip can transition from liquid to frozen on
Saturday night/early Sunday. I`ve been a bit aggressive in the
changeover in our far north overnight Saturday night, and when you
combine this changeover to the lighter precip that should be all
snow on Sunday snowfall totals are calculated in the 5-6 inch range
over our northern counties.  This may be a bit high considering the
850mb low track is directly over our northern counties, but if
precip can change over fast enough these numbers should be in the
ball park. Snowfall totals should then drop off as you head south,
with 1-3 inches along the I-70 corridor.  In our far southern
counties persistent low level WAA should cause the changeover to all
snow to be a struggle, so snowfall totals here should be under an
inch.

Snowfall forecasts will continue to evolve over the next 24 hours as
we try to fine-tune low level thermal profiles.  Obviously, if the
changeover to snow in the WAA band is delayed these amounts will
need to be adjusted down, but as mentioned above even if this
changeover is significantly delayed Saturday night, some measurable
snow should still be expected over northeast sections of the CWA on
Sunday.

Snow should taper off early Sunday evening, with Canadian high
bringing another round of cold air and below normal temperatures
to the region Sunday night and Monday.

(Tuesday-Thursday)

Temperatures should briefly moderate on Tuesday, followed by more
cold air and below normal temperatures for the Wednesday-Thursday
time frame. Forecasts will carry some low, slight chance PoPs
Wednesday-Thursday...tied to the next frontal passage.

Truett

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1139 PM CST Thu Jan 29 2015

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. KCOU has already scattered out as of 0530 UTC.
Further east...expect KUIN and metro TAF sites to remain
predominantly broken with periodic scattering through late
tonight. VFR conditions are expected thereafter with NNW winds
lightening up and becoming variable by afternoon as sfc high
approaches region.


Specifics for KSTL:

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. Further east...expect Lambert Field to remain
predominantly broken with periodic scattering through late
tonight/early Friday morning. VFR conditions are expected thereafter
with NNW winds lightening up and becoming variable by afternoon as
sfc high approaches region.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 300543
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1143 PM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 358 PM CST Thu Jan 29 2015

Although a few light flurries or sprinkles are still possible late
this afternoon, the secondary vort max which was providing weak
ascent will have moved east of the CWA by this evening. Gusty
northwest winds will start to subside overnight and turn northerly
in response to an area of high pressure which will be sliding into
the region. Overnight lows will be much cooler than last night due
to the colder post-frontal air mass.

Kanofsky

.LONG TERM:  (Friday through Next Thursday)
Issued at 358 PM CST Thu Jan 29 2015

The low level cloud cover should advect east of our forecast area
Friday morning as the upper level trough shifts well east of the
region and the strong surface ridge axis moves southeastward through
the forecast area on Friday.  Despite the solar insolation expected
the highs will be quite cold, although close to seasonal normals for
late January.  Mid-high level clouds will move into the region
Friday night ahead of the approaching storm system.  Rain should
spread northeastward into northeast and central portions of MO on
Saturday with increasing low-mid level moisture well ahead of the
southwestern US upper level low.  The NAM model was also depicting
mid level frontogenetical forcing across northeast MO and west
central IL south of an approaching cold front moving southward into
southern IA.  If the precipitation comes in early enough on
Saturday there could be a brief period of snow and sleet, but it
appears that the surface layer will warm up enough that most of the
precipitation on Saturday will be in the form of liquid rain.  The
precipitation should spread through the entire area by Saturday
evening and become heavier Saturday night as a strong northern
stream shortwave approaches our area.  Upper level divergence will
also be increasing over our region in the right entrance region of
an upper level jet streak over the Great Lakes region.  The rain
will change over to snow Saturday night as the cold front sags
southward through our area, along with increasing upward vertical
motion leading to more pseudo adiabatic cooling.  The better snow
accumulations Saturday night should be north and west of STL.
Precipitation in the form of snow will continue on Sunday for most
of our area as the upper level trough deepens over the region and a
surface low develops and moves northeastward through AR and into the
TN Valley region.  Prefer the GFS and ECMWF model solutions as the
NAM seems too deep with the surface low and a little too high on its
QPF.  There may be some lingering light snow or flurries Sunday
evening, but most of the accumulating snow should be over by this
time as a surface ridge builds southeastward into the region with
strong low level cold air advection and colder, below normal minimum
temperatures expected Sunday night.  Although there is still plenty
of model uncertainty it appears at this time that the highest snow
accumulations will likely occur across northeast MO and west central
IL with around 4-6 inches possible.  Lesser amounts of around 2 to 4
inches are possible further south across the rest of our area.
Later shifts may need to issue a winter storm watch for a portion of
the area as forecast confidence grows, and if the prefered models
indicate more QPF along with a quicker changeover from rain to
snow.  The GFS and ECMWF models had a northwest flow, clipper type
shortwave for Monday night, but it appears that any accumulating
snow with this system will be north of the forecast area.  A cold
front will drop southeastward through our region Tuesday night and
Wednesday morning as an upper level trough deepens over the Great
Lakes region.  This may bring some light rain/snow to our area,
followed by very cold temperatures for Wednesday night and
Thursday.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1139 PM CST Thu Jan 29 2015

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. KCOU has already scattered out as of 0530 UTC.
Further east...expect KUIN and metro TAF sites to remain
predominantly broken with periodic scattering through late
tonight. VFR conditions are expected thereafter with NNW winds
lightening up and becoming variable by afternoon as sfc high
approaches region.


Specifics for KSTL:

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. Further east...expect Lambert Field to remain
predominantly broken with periodic scattering through late
tonight/early Friday morning. VFR conditions are expected thereafter
with NNW winds lightening up and becoming variable by afternoon as
sfc high approaches region.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 300543
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1143 PM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 358 PM CST Thu Jan 29 2015

Although a few light flurries or sprinkles are still possible late
this afternoon, the secondary vort max which was providing weak
ascent will have moved east of the CWA by this evening. Gusty
northwest winds will start to subside overnight and turn northerly
in response to an area of high pressure which will be sliding into
the region. Overnight lows will be much cooler than last night due
to the colder post-frontal air mass.

Kanofsky

.LONG TERM:  (Friday through Next Thursday)
Issued at 358 PM CST Thu Jan 29 2015

The low level cloud cover should advect east of our forecast area
Friday morning as the upper level trough shifts well east of the
region and the strong surface ridge axis moves southeastward through
the forecast area on Friday.  Despite the solar insolation expected
the highs will be quite cold, although close to seasonal normals for
late January.  Mid-high level clouds will move into the region
Friday night ahead of the approaching storm system.  Rain should
spread northeastward into northeast and central portions of MO on
Saturday with increasing low-mid level moisture well ahead of the
southwestern US upper level low.  The NAM model was also depicting
mid level frontogenetical forcing across northeast MO and west
central IL south of an approaching cold front moving southward into
southern IA.  If the precipitation comes in early enough on
Saturday there could be a brief period of snow and sleet, but it
appears that the surface layer will warm up enough that most of the
precipitation on Saturday will be in the form of liquid rain.  The
precipitation should spread through the entire area by Saturday
evening and become heavier Saturday night as a strong northern
stream shortwave approaches our area.  Upper level divergence will
also be increasing over our region in the right entrance region of
an upper level jet streak over the Great Lakes region.  The rain
will change over to snow Saturday night as the cold front sags
southward through our area, along with increasing upward vertical
motion leading to more pseudo adiabatic cooling.  The better snow
accumulations Saturday night should be north and west of STL.
Precipitation in the form of snow will continue on Sunday for most
of our area as the upper level trough deepens over the region and a
surface low develops and moves northeastward through AR and into the
TN Valley region.  Prefer the GFS and ECMWF model solutions as the
NAM seems too deep with the surface low and a little too high on its
QPF.  There may be some lingering light snow or flurries Sunday
evening, but most of the accumulating snow should be over by this
time as a surface ridge builds southeastward into the region with
strong low level cold air advection and colder, below normal minimum
temperatures expected Sunday night.  Although there is still plenty
of model uncertainty it appears at this time that the highest snow
accumulations will likely occur across northeast MO and west central
IL with around 4-6 inches possible.  Lesser amounts of around 2 to 4
inches are possible further south across the rest of our area.
Later shifts may need to issue a winter storm watch for a portion of
the area as forecast confidence grows, and if the prefered models
indicate more QPF along with a quicker changeover from rain to
snow.  The GFS and ECMWF models had a northwest flow, clipper type
shortwave for Monday night, but it appears that any accumulating
snow with this system will be north of the forecast area.  A cold
front will drop southeastward through our region Tuesday night and
Wednesday morning as an upper level trough deepens over the Great
Lakes region.  This may bring some light rain/snow to our area,
followed by very cold temperatures for Wednesday night and
Thursday.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1139 PM CST Thu Jan 29 2015

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. KCOU has already scattered out as of 0530 UTC.
Further east...expect KUIN and metro TAF sites to remain
predominantly broken with periodic scattering through late
tonight. VFR conditions are expected thereafter with NNW winds
lightening up and becoming variable by afternoon as sfc high
approaches region.


Specifics for KSTL:

Focus over the next several hours will remain on stratus deck
across most of area. Satellite trends have shown dissipation of
stratus deck over the past several hours...especially on the
western fringe. Further east...expect Lambert Field to remain
predominantly broken with periodic scattering through late
tonight/early Friday morning. VFR conditions are expected thereafter
with NNW winds lightening up and becoming variable by afternoon as
sfc high approaches region.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 292334
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
534 PM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 358 PM CST Thu Jan 29 2015

Although a few light flurries or sprinkles are still possible late
this afternoon, the secondary vort max which was providing weak
ascent will have moved east of the CWA by this evening. Gusty
northwest winds will start to subside overnight and turn northerly
in response to an area of high pressure which will be sliding into
the region. Overnight lows will be much cooler than last night due
to the colder post-frontal air mass.

Kanofsky

.LONG TERM:  (Friday through Next Thursday)
Issued at 358 PM CST Thu Jan 29 2015

The low level cloud cover should advect east of our forecast area
Friday morning as the upper level trough shifts well east of the
region and the strong surface ridge axis moves southeastward through
the forecast area on Friday.  Despite the solar insolation expected
the highs will be quite cold, although close to seasonal normals for
late January.  Mid-high level clouds will move into the region
Friday night ahead of the approaching storm system.  Rain should
spread northeastward into northeast and central portions of MO on
Saturday with increasing low-mid level moisture well ahead of the
southwestern US upper level low.  The NAM model was also depicting
mid level frontogenetical forcing across northeast MO and west
central IL south of an approaching cold front moving southward into
southern IA.  If the precipitation comes in early enough on
Saturday there could be a brief period of snow and sleet, but it
appears that the surface layer will warm up enough that most of the
precipitation on Saturday will be in the form of liquid rain.  The
precipitation should spread through the entire area by Saturday
evening and become heavier Saturday night as a strong northern
stream shortwave approaches our area.  Upper level divergence will
also be increasing over our region in the right entrance region of
an upper level jet streak over the Great Lakes region.  The rain
will change over to snow Saturday night as the cold front sags
southward through our area, along with increasing upward vertical
motion leading to more pseudo adiabatic cooling.  The better snow
accumulations Saturday night should be north and west of STL.
Precipitation in the form of snow will continue on Sunday for most
of our area as the upper level trough deepens over the region and a
surface low develops and moves northeastward through AR and into the
TN Valley region.  Prefer the GFS and ECMWF model solutions as the
NAM seems too deep with the surface low and a little too high on its
QPF.  There may be some lingering light snow or flurries Sunday
evening, but most of the accumulating snow should be over by this
time as a surface ridge builds southeastward into the region with
strong low level cold air advection and colder, below normal minimum
temperatures expected Sunday night.  Although there is still plenty
of model uncertainty it appears at this time that the highest snow
accumulations will likely occur across northeast MO and west central
IL with around 4-6 inches possible.  Lesser amounts of around 2 to 4
inches are possible further south across the rest of our area.
Later shifts may need to issue a winter storm watch for a portion of
the area as forecast confidence grows, and if the prefered models
indicate more QPF along with a quicker changeover from rain to
snow.  The GFS and ECMWF models had a northwest flow, clipper type
shortwave for Monday night, but it appears that any accumulating
snow with this system will be north of the forecast area.  A cold
front will drop southeastward through our region Tuesday night and
Wednesday morning as an upper level trough deepens over the Great
Lakes region.  This may bring some light rain/snow to our area,
followed by very cold temperatures for Wednesday night and
Thursday.

GKS

&&

.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 530 PM CST Thu Jan 29 2015

Primary concern for tonight and into early on Friday will be on
timing the dissipation/scattering out of MVFR ceilings across the
region. Current satellite imagery depicts OVC MVFR stratus deck up
into Minnesota slowly sliding south and east. Believe tonight will
continue to be overcast with scattering out of stratus by mid
morning. Surface ridge will move toward area by Friday afternoon
yielding light and variable winds.


Specifics for KSTL:

Primary concern for tonight and into early on Friday will be on
timing the dissipation/scattering out of MVFR ceilings. Current
satellite imagery depicts OVC MVFR stratus deck up into Minnesota
slowly sliding south and east. Believe tonight will continue to be
overcast with scattering out of stratus around 1400 UTC. Surface
ridge will move toward area by Friday afternoon yielding light and
variable winds heading into Friday night.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 292334
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
534 PM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 358 PM CST Thu Jan 29 2015

Although a few light flurries or sprinkles are still possible late
this afternoon, the secondary vort max which was providing weak
ascent will have moved east of the CWA by this evening. Gusty
northwest winds will start to subside overnight and turn northerly
in response to an area of high pressure which will be sliding into
the region. Overnight lows will be much cooler than last night due
to the colder post-frontal air mass.

Kanofsky

.LONG TERM:  (Friday through Next Thursday)
Issued at 358 PM CST Thu Jan 29 2015

The low level cloud cover should advect east of our forecast area
Friday morning as the upper level trough shifts well east of the
region and the strong surface ridge axis moves southeastward through
the forecast area on Friday.  Despite the solar insolation expected
the highs will be quite cold, although close to seasonal normals for
late January.  Mid-high level clouds will move into the region
Friday night ahead of the approaching storm system.  Rain should
spread northeastward into northeast and central portions of MO on
Saturday with increasing low-mid level moisture well ahead of the
southwestern US upper level low.  The NAM model was also depicting
mid level frontogenetical forcing across northeast MO and west
central IL south of an approaching cold front moving southward into
southern IA.  If the precipitation comes in early enough on
Saturday there could be a brief period of snow and sleet, but it
appears that the surface layer will warm up enough that most of the
precipitation on Saturday will be in the form of liquid rain.  The
precipitation should spread through the entire area by Saturday
evening and become heavier Saturday night as a strong northern
stream shortwave approaches our area.  Upper level divergence will
also be increasing over our region in the right entrance region of
an upper level jet streak over the Great Lakes region.  The rain
will change over to snow Saturday night as the cold front sags
southward through our area, along with increasing upward vertical
motion leading to more pseudo adiabatic cooling.  The better snow
accumulations Saturday night should be north and west of STL.
Precipitation in the form of snow will continue on Sunday for most
of our area as the upper level trough deepens over the region and a
surface low develops and moves northeastward through AR and into the
TN Valley region.  Prefer the GFS and ECMWF model solutions as the
NAM seems too deep with the surface low and a little too high on its
QPF.  There may be some lingering light snow or flurries Sunday
evening, but most of the accumulating snow should be over by this
time as a surface ridge builds southeastward into the region with
strong low level cold air advection and colder, below normal minimum
temperatures expected Sunday night.  Although there is still plenty
of model uncertainty it appears at this time that the highest snow
accumulations will likely occur across northeast MO and west central
IL with around 4-6 inches possible.  Lesser amounts of around 2 to 4
inches are possible further south across the rest of our area.
Later shifts may need to issue a winter storm watch for a portion of
the area as forecast confidence grows, and if the prefered models
indicate more QPF along with a quicker changeover from rain to
snow.  The GFS and ECMWF models had a northwest flow, clipper type
shortwave for Monday night, but it appears that any accumulating
snow with this system will be north of the forecast area.  A cold
front will drop southeastward through our region Tuesday night and
Wednesday morning as an upper level trough deepens over the Great
Lakes region.  This may bring some light rain/snow to our area,
followed by very cold temperatures for Wednesday night and
Thursday.

GKS

&&

.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 530 PM CST Thu Jan 29 2015

Primary concern for tonight and into early on Friday will be on
timing the dissipation/scattering out of MVFR ceilings across the
region. Current satellite imagery depicts OVC MVFR stratus deck up
into Minnesota slowly sliding south and east. Believe tonight will
continue to be overcast with scattering out of stratus by mid
morning. Surface ridge will move toward area by Friday afternoon
yielding light and variable winds.


Specifics for KSTL:

Primary concern for tonight and into early on Friday will be on
timing the dissipation/scattering out of MVFR ceilings. Current
satellite imagery depicts OVC MVFR stratus deck up into Minnesota
slowly sliding south and east. Believe tonight will continue to be
overcast with scattering out of stratus around 1400 UTC. Surface
ridge will move toward area by Friday afternoon yielding light and
variable winds heading into Friday night.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 292159
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
359 PM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 358 PM CST Thu Jan 29 2015

Although a few light flurries or sprinkles are still possible late
this afternoon, the secondary vort max which was providing weak
ascent will have moved east of the CWA by this evening. Gusty
northwest winds will start to subside overnight and turn northerly
in response to an area of high pressure which will be sliding into
the region. Overnight lows will be much cooler than last night due
to the colder post-frontal air mass.

Kanofsky

.LONG TERM:  (Friday through Next Thursday)
Issued at 358 PM CST Thu Jan 29 2015

The low level cloud cover should advect east of our forecast area
Friday morning as the upper level trough shifts well east of the
region and the strong surface ridge axis moves southeastward through
the forecast area on Friday.  Despite the solar insolation expected
the highs will be quite cold, although close to seasonal normals for
late January.  Mid-high level clouds will move into the region
Friday night ahead of the approaching storm system.  Rain should
spread northeastward into northeast and central portions of MO on
Saturday with increasing low-mid level moisture well ahead of the
southwestern US upper level low.  The NAM model was also depicting
mid level frontogenetical forcing across northeast MO and west
central IL south of an approaching cold front moving southward into
southern IA.  If the precipitation comes in early enough on
Saturday there could be a brief period of snow and sleet, but it
appears that the surface layer will warm up enough that most of the
precipitation on Saturday will be in the form of liquid rain.  The
precipitation should spread through the entire area by Saturday
evening and become heavier Saturday night as a strong northern
stream shortwave approaches our area.  Upper level divergence will
also be increasing over our region in the right entrance region of
an upper level jet streak over the Great Lakes region.  The rain
will change over to snow Saturday night as the cold front sags
southward through our area, along with increasing upward vertical
motion leading to more pseudo adiabatic cooling.  The better snow
accumulations Saturday night should be north and west of STL.
Precipitation in the form of snow will continue on Sunday for most
of our area as the upper level trough deepens over the region and a
surface low develops and moves northeastward through AR and into the
TN Valley region.  Prefer the GFS and ECMWF model solutions as the
NAM seems too deep with the surface low and a little too high on its
QPF.  There may be some lingering light snow or flurries Sunday
evening, but most of the accumulating snow should be over by this
time as a surface ridge builds southeastward into the region with
strong low level cold air advection and colder, below normal minimum
temperatures expected Sunday night.  Although there is still plenty
of model uncertainty it appears at this time that the highest snow
accumulations will likely occur across northeast MO and west central
IL with around 4-6 inches possible.  Lesser amounts of around 2 to 4
inches are possible further south across the rest of our area.
Later shifts may need to issue a winter storm watch for a portion of
the area as forecast confidence grows, and if the prefered models
indicate more QPF along with a quicker changeover from rain to
snow.  The GFS and ECMWF models had a northwest flow, clipper type
shortwave for Monday night, but it appears that any accumulating
snow with this system will be north of the forecast area.  A cold
front will drop southeastward through our region Tuesday night and
Wednesday morning as an upper level trough deepens over the Great
Lakes region.  This may bring some light rain/snow to our area,
followed by very cold temperatures for Wednesday night and
Thursday.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1121 AM CST Thu Jan 29 2015

MVFR clouds stretch nearly to the Canadian border and winds at
cloud level are out of the northwest. This should keep MVFR clouds
(generally 1500-3000 ft) in place for the rest of the day and
overnight. Clouds are expected to diminish tomorrow morning after
a low pressure system has moved farther away from the region and
drier air starts to erode the western edge of the cloud shield.
Gusty northwest winds will diminish and become more northerly
overnight.

Kanofsky

&&

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

$$

WFO LSX







000
FXUS63 KLSX 291759
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1159 AM CST Thu Jan 29 2015

.UPDATE:
Issued at 1157 AM CST Thu Jan 29 2015

Updated grids and products have been sent to reflect increased
cloud cover and minor tweaks to the wind speeds through this
afternoon.

Kanofsky

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1121 AM CST Thu Jan 29 2015

MVFR clouds stretch nearly to the Canadian border and winds at
cloud level are out of the northwest. This should keep MVFR clouds
(generally 1500-3000 ft) in place for the rest of the day and
overnight. Clouds are expected to diminish tomorrow morning after
a low pressure system has moved farther away from the region and
drier air starts to erode the western edge of the cloud shield.
Gusty northwest winds will diminish and become more northerly
overnight.

Kanofsky

&&

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

$$

WFO LSX








000
FXUS63 KLSX 291759
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1159 AM CST Thu Jan 29 2015

.UPDATE:
Issued at 1157 AM CST Thu Jan 29 2015

Updated grids and products have been sent to reflect increased
cloud cover and minor tweaks to the wind speeds through this
afternoon.

Kanofsky

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1121 AM CST Thu Jan 29 2015

MVFR clouds stretch nearly to the Canadian border and winds at
cloud level are out of the northwest. This should keep MVFR clouds
(generally 1500-3000 ft) in place for the rest of the day and
overnight. Clouds are expected to diminish tomorrow morning after
a low pressure system has moved farther away from the region and
drier air starts to erode the western edge of the cloud shield.
Gusty northwest winds will diminish and become more northerly
overnight.

Kanofsky

&&

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

$$

WFO LSX







000
FXUS63 KLSX 291728
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1128 AM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1121 AM CST Thu Jan 29 2015

MVFR clouds stretch nearly to the Canadian border and winds at
cloud level are out of the northwest. This should keep MVFR clouds
(generally 1500-3000 ft) in place for the rest of the day and
overnight. Clouds are expected to diminish tomorrow morning after
a low pressure system has moved farther away from the region and
drier air starts to erode the western edge of the cloud shield.
Gusty northwest winds will diminish and become more northerly
overnight.

Kanofsky

&&

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

$$

WFO LSX








000
FXUS63 KLSX 291728
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1128 AM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1121 AM CST Thu Jan 29 2015

MVFR clouds stretch nearly to the Canadian border and winds at
cloud level are out of the northwest. This should keep MVFR clouds
(generally 1500-3000 ft) in place for the rest of the day and
overnight. Clouds are expected to diminish tomorrow morning after
a low pressure system has moved farther away from the region and
drier air starts to erode the western edge of the cloud shield.
Gusty northwest winds will diminish and become more northerly
overnight.

Kanofsky

&&

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

$$

WFO LSX







000
FXUS63 KLSX 291045
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
445 AM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd

&&

.AVIATION:  (For the 12z TAFs through 12z Friday Morning)
Issued at 445 AM CST Thu Jan 29 2015

Strong gusty NW winds and MVFR CIGs will be the rule for today for
all TAF sites. While there will be a tendency for CIGs to be below
2000 ft this morning, they should bump up to the 2000-3000 ft
range this afternoon before lowering again some tonight. There is
increasing indications that tonight the clouds will hang in for
much of the night, with some clearing potential from the north
late. Gusts should also diminish this evening. Some potential for
sprinkles or flurries for UIN early this morning but spotty nature
of pcpn will probably preclude any mention in the TAF.

Specifics for KSTL: gusty NW winds and MVFR CIGs will prevail
today with diminishing winds and persistent MVFR CIGs tonight.
It now looks like clearing will occur around daybreak Friday from
the north.

TES

&&

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

$$

WFO LSX





000
FXUS63 KLSX 291045
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
445 AM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd

&&

.AVIATION:  (For the 12z TAFs through 12z Friday Morning)
Issued at 445 AM CST Thu Jan 29 2015

Strong gusty NW winds and MVFR CIGs will be the rule for today for
all TAF sites. While there will be a tendency for CIGs to be below
2000 ft this morning, they should bump up to the 2000-3000 ft
range this afternoon before lowering again some tonight. There is
increasing indications that tonight the clouds will hang in for
much of the night, with some clearing potential from the north
late. Gusts should also diminish this evening. Some potential for
sprinkles or flurries for UIN early this morning but spotty nature
of pcpn will probably preclude any mention in the TAF.

Specifics for KSTL: gusty NW winds and MVFR CIGs will prevail
today with diminishing winds and persistent MVFR CIGs tonight.
It now looks like clearing will occur around daybreak Friday from
the north.

TES

&&

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

$$

WFO LSX






000
FXUS63 KLSX 290949
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
349 AM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd
&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CST Wed Jan 28 2015

Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected
within a few hours after fropa...along with winds sharply veering
to the northwest along with gusts 20-30 knots. Some uncertainty as
to how long these ceilings will persist. For now continued to lean
a bit pessimistic given expansive OVC deck on 11-3.9 micron
satellite imagery. NAM guidance looked pretty good and followed
closely for ceiling trends through the day on Saturday. This
resulted in TAFs with ceilings rising and then scattering out by
afternoon.

Specifics for KSTL:
Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected by
1200 UTC behind the front..along with winds sharply veering to the
northwest. Some uncertainty as to how long these ceilings will
persist. For now continued to lean a bit pessimistic given
expansive OVC deck on 11-3.9 micron satellite imagery. NAM
guidance looked pretty good and followed closely for ceiling
trends through the day on Thursday. Winds should slacken up a bit
as sfc ridge approaches area on Thursday night.

Gosselin
&&

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

$$
WFO LSX







000
FXUS63 KLSX 290949
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
349 AM CST Thu Jan 29 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CST Thu Jan 29 2015

Observational data at 08z indicated a low pressure area over
northwest IL with a cold front extending to the southwest of it thru
UIN and COU.  A warm front extended from near UIN southeastward thru
southern IL.  Temps have stayed up or risen into the 50s in the warm
sector of this system, and then have plunged into the 30s quickly
behind the cold front in IA and far northwest MO.  Satellite data
shows low clouds move in shortly after cold frontal passage with
plenty more where they came from over the Upper Midwest and northern
Plains.  Radar data shows generally echo-free mosaics over our
region but some obs at ground level have indicated spotty sprinkles
or drizzle underneath the low cloud shield that moves in.
Otherwise, an upper level disturbance was over northern MO early
this morning with another further upstream over eastern SD--all part
of the northwest flow aloft that is in place.

The cold front will push thru the forecast area by 15z with low
clouds to then inundate and persist for the remainder of the day.
Some clearing is then expected in central MO late, possibly
spreading eastward into tonight.  High temperatures for the day,
technically, will all be hit early this morning.  But for daytime
purposes, we should see near steady temps after the initial fall
shortly after frontal passage.  This favors at or below the coolest
MOS for most locales, except near the front after daybreak for areas
south and east of STL metro, where the warmer MAV MOS will probably
work out better given the gradient.

Pcpn will be a tough call today since there is not much to latch on
to and radar is having a tough time picking it up.  Added some
scattered sprinkles or flurries for northern MO and central IL thru
this morning where it looks like there will be some better upper
level support and lift as well as low level convergence.  These
should all be significantly reduced by 18z and have kept the
afternoon pcpn-free.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 343 AM CST Thu Jan 29 2015

Surface ridge to build into the region tonight with northwest winds
gradually diminishing. Colder air to filter in with lows in the low
to mid 20s.

On Friday, mostly sunny skies to prevail but temperatures will only
rise into the low 30s east to low 40s west.

Surface ridge to move off to the east late Friday night allowing
southerly winds to return once again ahead of next weather system.
However, lows will still be in the 20s Friday night.

As for next weather system, models still have differences with
placement and timing of frontal boundary. NAM is the slowest and
warmest initially while the GFS and ECMWF are a bit faster and
colder. Will side more with GFS/ECMWF solutions, with precipitation
beginning during the day Saturday and spreading east. It will begin
as a mix of rain and snow, transition to mostly rain briefly during
the afternoon hours with highs in the low 40s. Then as colder air
filters in rather quickly, precipitation to change to all snow
everywhere just after 00z Sunday. As for precipitation amounts, both
the GFS and ECMWF 00z Thursday runs are showing highest values along
the I-70 corridor. However, since there continues to be plenty of
model differences with this storm, it is difficult to determine
snowfall amounts and where the maximum axis of snow will occur. For
now it still does appear that at least a portion of our forecast
area will see accumulating snow Saturday night and Sunday.

Beyond that, the precipitation will come to an end Sunday night with
colder air filtering in and temperatures at or below normal for the
rest of the forecast period. Extended models do indicate a clipper
system will slide through Tuesday night and Wednesday with most of
the energy to the north of the forecast area, so kept slight chance
pops through the period.

Byrd
&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CST Wed Jan 28 2015

Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected
within a few hours after fropa...along with winds sharply veering
to the northwest along with gusts 20-30 knots. Some uncertainty as
to how long these ceilings will persist. For now continued to lean
a bit pessimistic given expansive OVC deck on 11-3.9 micron
satellite imagery. NAM guidance looked pretty good and followed
closely for ceiling trends through the day on Saturday. This
resulted in TAFs with ceilings rising and then scattering out by
afternoon.

Specifics for KSTL:
Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected by
1200 UTC behind the front..along with winds sharply veering to the
northwest. Some uncertainty as to how long these ceilings will
persist. For now continued to lean a bit pessimistic given
expansive OVC deck on 11-3.9 micron satellite imagery. NAM
guidance looked pretty good and followed closely for ceiling
trends through the day on Thursday. Winds should slacken up a bit
as sfc ridge approaches area on Thursday night.

Gosselin
&&

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

$$
WFO LSX






000
FXUS63 KLSX 290542
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1142 PM CST Wed Jan 28 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 402 PM CST Wed Jan 28 2015

Shortwave over the Nebraska panhandle and eastern CO and associated
surface low ahead of it over eastern Nebraska will move eastward
through northern MO and southern IA tonight.  The surface low will
drag a cold front southeastward through our forecast area late
tonight and Thursday morning.  Most of the models have the
precipitation north of the surface low track, although the ECMWF
model does generate light qpf across IL already this evening in the
warm air advection regime ahead of the shortwave.  The models were
also depicting upper level divergence centered over northeast MO and
west central IL, mainly late tonight in the left exit region of an
upper level jet streak dropping into southwest MO.  The quality and
depth of moisture is quite limited with this system so will only
include slight chance pops across west centrl and southwest IL,
mainly late tonight into Thursday morning.   A tight surface
pressure gradient along with a strong southwesterly low level jet
will lead to relatively strong surface winds for the nightime
hours.  Low temperatures will be above normal tonight as the strong
cold air advection behind the front will not impact most of the area
until Thursday morning.

GKS

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 402 PM CST Wed Jan 28 2015

Colder conditions are expected on Thursday due to low level cold air
advection with strong and gusty northwest winds behind the cold
front, along with post frontal low level cloudiness to limit solar
insolation.  Little diurnal temperature range is expected with some
areas likely having nearly steady or slightly falling temperatures
during the late morning and afternoon hours.  These clouds should
clear out Thursday night as subsidence increases over our area as a
strong surface ridge over the northern Plains builds southeastward
into the region.  Cold conditions will continue Thursday night and
Friday with near normal temperatures for late January.
Precipitation is expected to spread into our area by Saturday
afternoon and evening as moisture spreads into our region ahead of
the southwestern US upper level low, and as a strong northern stream
shortwave approaches from the northern Plains.  Initially it appears
that surface temperatures will be warm enough Saturday afternoon
into the evening that any precipiation at this time should fall as
liquid rain.  As a cold front sags southward through our forecast
area Saturday night into Sunday as the upper level trough gradually
deepens over the northern Plains and Great Lakes region the
precipitation should change over to snow.  The ECMWF model has most
of its QPF along and south of I-70 Saturday night and Sunday.  The
GFS is similar although it does have a little more qpf across
northern MO and west central IL compared to the ECMWF.  There has
been plenty of model differences along with run to run
inconsistencies with this weekend storm system and hence it has been
difficult to determine precipitation amounts and types across our
area.  For now it does appear that at least a portion of our
forecast area will see accumulating snow Saturday night and Sunday,
but the snowfall amounts and where the maximum axis of snow will
occur is still in question.  Much colder, below normal temperatures
can be expected for Sunday night through Monday night with the
models dropping the -12 degree C 850 mb isotherm southward into our
forecast area Sunday afternoon.  Monday and Tuesday will likely be
dry as snow associated with northwest flow shortwaves should be
north of our area, and any precipitation associated with the
southwest US upper level low finally moving eastward through the
southern Plains and Gulf Coast region will be well south of our area.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CST Wed Jan 28 2015


Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected
within a few hours after fropa...along with winds sharply veering
to the northwest along with gusts 20-30 knots. Some uncertainty as
to how long these ceilings will persist. For now continued to lean
a bit pessisimistic given expansive OVC deck on 11-3.9 micron
satellite imagery. NAM guidance looked pretty good and followed
closely for ceiling trends through the day on Saturday. This
resulted in TAFs with ceilings rising and then scattering out by
afternoon.


Specifics for KSTL:

Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected
by 1200 UTC behind the front..along with winds sharply veering
to the northwest. Some uncertainty as to how long these ceilings
will persist. For now continued to lean a bit pessisimistic given
expansive OVC deck on 11-3.9 micron satellite imagery. NAM
guidance looked pretty good and followed closely for ceiling
trends through the day on Thursday. Winds should slacken up a bit
as sfc ridge approaches area on Thursday night.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 290542
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1142 PM CST Wed Jan 28 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 402 PM CST Wed Jan 28 2015

Shortwave over the Nebraska panhandle and eastern CO and associated
surface low ahead of it over eastern Nebraska will move eastward
through northern MO and southern IA tonight.  The surface low will
drag a cold front southeastward through our forecast area late
tonight and Thursday morning.  Most of the models have the
precipitation north of the surface low track, although the ECMWF
model does generate light qpf across IL already this evening in the
warm air advection regime ahead of the shortwave.  The models were
also depicting upper level divergence centered over northeast MO and
west central IL, mainly late tonight in the left exit region of an
upper level jet streak dropping into southwest MO.  The quality and
depth of moisture is quite limited with this system so will only
include slight chance pops across west centrl and southwest IL,
mainly late tonight into Thursday morning.   A tight surface
pressure gradient along with a strong southwesterly low level jet
will lead to relatively strong surface winds for the nightime
hours.  Low temperatures will be above normal tonight as the strong
cold air advection behind the front will not impact most of the area
until Thursday morning.

GKS

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 402 PM CST Wed Jan 28 2015

Colder conditions are expected on Thursday due to low level cold air
advection with strong and gusty northwest winds behind the cold
front, along with post frontal low level cloudiness to limit solar
insolation.  Little diurnal temperature range is expected with some
areas likely having nearly steady or slightly falling temperatures
during the late morning and afternoon hours.  These clouds should
clear out Thursday night as subsidence increases over our area as a
strong surface ridge over the northern Plains builds southeastward
into the region.  Cold conditions will continue Thursday night and
Friday with near normal temperatures for late January.
Precipitation is expected to spread into our area by Saturday
afternoon and evening as moisture spreads into our region ahead of
the southwestern US upper level low, and as a strong northern stream
shortwave approaches from the northern Plains.  Initially it appears
that surface temperatures will be warm enough Saturday afternoon
into the evening that any precipiation at this time should fall as
liquid rain.  As a cold front sags southward through our forecast
area Saturday night into Sunday as the upper level trough gradually
deepens over the northern Plains and Great Lakes region the
precipitation should change over to snow.  The ECMWF model has most
of its QPF along and south of I-70 Saturday night and Sunday.  The
GFS is similar although it does have a little more qpf across
northern MO and west central IL compared to the ECMWF.  There has
been plenty of model differences along with run to run
inconsistencies with this weekend storm system and hence it has been
difficult to determine precipitation amounts and types across our
area.  For now it does appear that at least a portion of our
forecast area will see accumulating snow Saturday night and Sunday,
but the snowfall amounts and where the maximum axis of snow will
occur is still in question.  Much colder, below normal temperatures
can be expected for Sunday night through Monday night with the
models dropping the -12 degree C 850 mb isotherm southward into our
forecast area Sunday afternoon.  Monday and Tuesday will likely be
dry as snow associated with northwest flow shortwaves should be
north of our area, and any precipitation associated with the
southwest US upper level low finally moving eastward through the
southern Plains and Gulf Coast region will be well south of our area.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CST Wed Jan 28 2015


Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected
within a few hours after fropa...along with winds sharply veering
to the northwest along with gusts 20-30 knots. Some uncertainty as
to how long these ceilings will persist. For now continued to lean
a bit pessisimistic given expansive OVC deck on 11-3.9 micron
satellite imagery. NAM guidance looked pretty good and followed
closely for ceiling trends through the day on Saturday. This
resulted in TAFs with ceilings rising and then scattering out by
afternoon.


Specifics for KSTL:

Cold front has moved through central Missouri and should pass
through the TAF sites late tonight. MVFR ceilings are expected
by 1200 UTC behind the front..along with winds sharply veering
to the northwest. Some uncertainty as to how long these ceilings
will persist. For now continued to lean a bit pessisimistic given
expansive OVC deck on 11-3.9 micron satellite imagery. NAM
guidance looked pretty good and followed closely for ceiling
trends through the day on Thursday. Winds should slacken up a bit
as sfc ridge approaches area on Thursday night.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 282338
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
538 PM CST Wed Jan 28 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 402 PM CST Wed Jan 28 2015

Shortwave over the Nebraska panhandle and eastern CO and associated
surface low ahead of it over eastern Nebraska will move eastward
through northern MO and southern IA tonight.  The surface low will
drag a cold front southeastward through our forecast area late
tonight and Thursday morning.  Most of the models have the
precipitation north of the surface low track, although the ECMWF
model does generate light qpf across IL already this evening in the
warm air advection regime ahead of the shortwave.  The models were
also depicting upper level divergence centered over northeast MO and
west central IL, mainly late tonight in the left exit region of an
upper level jet streak dropping into southwest MO.  The quality and
depth of moisture is quite limited with this system so will only
include slight chance pops across west centrl and southwest IL,
mainly late tonight into Thursday morning.   A tight surface
pressure gradient along with a strong southwesterly low level jet
will lead to relatively strong surface winds for the nightime
hours.  Low temperatures will be above normal tonight as the strong
cold air advection behind the front will not impact most of the area
until Thursday morning.

GKS

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 402 PM CST Wed Jan 28 2015

Colder conditions are expected on Thursday due to low level cold air
advection with strong and gusty northwest winds behind the cold
front, along with post frontal low level cloudiness to limit solar
insolation.  Little diurnal temperature range is expected with some
areas likely having nearly steady or slightly falling temperatures
during the late morning and afternoon hours.  These clouds should
clear out Thursday night as subsidence increases over our area as a
strong surface ridge over the northern Plains builds southeastward
into the region.  Cold conditions will continue Thursday night and
Friday with near normal temperatures for late January.
Precipitation is expected to spread into our area by Saturday
afternoon and evening as moisture spreads into our region ahead of
the southwestern US upper level low, and as a strong northern stream
shortwave approaches from the northern Plains.  Initially it appears
that surface temperatures will be warm enough Saturday afternoon
into the evening that any precipiation at this time should fall as
liquid rain.  As a cold front sags southward through our forecast
area Saturday night into Sunday as the upper level trough gradually
deepens over the northern Plains and Great Lakes region the
precipitation should change over to snow.  The ECMWF model has most
of its QPF along and south of I-70 Saturday night and Sunday.  The
GFS is similar although it does have a little more qpf across
northern MO and west central IL compared to the ECMWF.  There has
been plenty of model differences along with run to run
inconsistencies with this weekend storm system and hence it has been
difficult to determine precipitation amounts and types across our
area.  For now it does appear that at least a portion of our
forecast area will see accumulating snow Saturday night and Sunday,
but the snowfall amounts and where the maximum axis of snow will
occur is still in question.  Much colder, below normal temperatures
can be expected for Sunday night through Monday night with the
models dropping the -12 degree C 850 mb isotherm southward into our
forecast area Sunday afternoon.  Monday and Tuesday will likely be
dry as snow associated with northwest flow shortwaves should be
north of our area, and any precipitation associated with the
southwest US upper level low finally moving eastward through the
southern Plains and Gulf Coast region will be well south of our area.

GKS

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 525 PM CST Wed Jan 28 2015

Next weather system will move through the bi-state area overnight
tonight. Terminals are expected to remain dry but impacts include
some low-level wind shear tonight along with some MVFR ceilings
behind the passage of the cold front. Wind gusts will subside this
evening before ramping back up late tonight/early Thursday after
frontal passage as winds become northwesterly. Ceilings are
expected to gradually lift during the day on Thursday before
scattering out by afternoon.


Specifics for KSTL:

Next weather system will move through the terminal overnight
tonight. System is expected to pass through dry but impacts include some
low-level wind shear tonight along with some MVFR ceilings behind
the passage of the cold front. Wind gusts will subside this
evening before ramping back up late tonight/early Thursday after
frontal passage as winds become northwesterly. Ceilings are
expected to gradually lift during the day on Thursday before
scattering out by afternoon.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 282338
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
538 PM CST Wed Jan 28 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 402 PM CST Wed Jan 28 2015

Shortwave over the Nebraska panhandle and eastern CO and associated
surface low ahead of it over eastern Nebraska will move eastward
through northern MO and southern IA tonight.  The surface low will
drag a cold front southeastward through our forecast area late
tonight and Thursday morning.  Most of the models have the
precipitation north of the surface low track, although the ECMWF
model does generate light qpf across IL already this evening in the
warm air advection regime ahead of the shortwave.  The models were
also depicting upper level divergence centered over northeast MO and
west central IL, mainly late tonight in the left exit region of an
upper level jet streak dropping into southwest MO.  The quality and
depth of moisture is quite limited with this system so will only
include slight chance pops across west centrl and southwest IL,
mainly late tonight into Thursday morning.   A tight surface
pressure gradient along with a strong southwesterly low level jet
will lead to relatively strong surface winds for the nightime
hours.  Low temperatures will be above normal tonight as the strong
cold air advection behind the front will not impact most of the area
until Thursday morning.

GKS

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 402 PM CST Wed Jan 28 2015

Colder conditions are expected on Thursday due to low level cold air
advection with strong and gusty northwest winds behind the cold
front, along with post frontal low level cloudiness to limit solar
insolation.  Little diurnal temperature range is expected with some
areas likely having nearly steady or slightly falling temperatures
during the late morning and afternoon hours.  These clouds should
clear out Thursday night as subsidence increases over our area as a
strong surface ridge over the northern Plains builds southeastward
into the region.  Cold conditions will continue Thursday night and
Friday with near normal temperatures for late January.
Precipitation is expected to spread into our area by Saturday
afternoon and evening as moisture spreads into our region ahead of
the southwestern US upper level low, and as a strong northern stream
shortwave approaches from the northern Plains.  Initially it appears
that surface temperatures will be warm enough Saturday afternoon
into the evening that any precipiation at this time should fall as
liquid rain.  As a cold front sags southward through our forecast
area Saturday night into Sunday as the upper level trough gradually
deepens over the northern Plains and Great Lakes region the
precipitation should change over to snow.  The ECMWF model has most
of its QPF along and south of I-70 Saturday night and Sunday.  The
GFS is similar although it does have a little more qpf across
northern MO and west central IL compared to the ECMWF.  There has
been plenty of model differences along with run to run
inconsistencies with this weekend storm system and hence it has been
difficult to determine precipitation amounts and types across our
area.  For now it does appear that at least a portion of our
forecast area will see accumulating snow Saturday night and Sunday,
but the snowfall amounts and where the maximum axis of snow will
occur is still in question.  Much colder, below normal temperatures
can be expected for Sunday night through Monday night with the
models dropping the -12 degree C 850 mb isotherm southward into our
forecast area Sunday afternoon.  Monday and Tuesday will likely be
dry as snow associated with northwest flow shortwaves should be
north of our area, and any precipitation associated with the
southwest US upper level low finally moving eastward through the
southern Plains and Gulf Coast region will be well south of our area.

GKS

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 525 PM CST Wed Jan 28 2015

Next weather system will move through the bi-state area overnight
tonight. Terminals are expected to remain dry but impacts include
some low-level wind shear tonight along with some MVFR ceilings
behind the passage of the cold front. Wind gusts will subside this
evening before ramping back up late tonight/early Thursday after
frontal passage as winds become northwesterly. Ceilings are
expected to gradually lift during the day on Thursday before
scattering out by afternoon.


Specifics for KSTL:

Next weather system will move through the terminal overnight
tonight. System is expected to pass through dry but impacts include some
low-level wind shear tonight along with some MVFR ceilings behind
the passage of the cold front. Wind gusts will subside this
evening before ramping back up late tonight/early Thursday after
frontal passage as winds become northwesterly. Ceilings are
expected to gradually lift during the day on Thursday before
scattering out by afternoon.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 282203
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
403 PM CST Wed Jan 28 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 402 PM CST Wed Jan 28 2015

Shortwave over the Nebraska panhandle and eastern CO and associated
surface low ahead of it over eastern Nebraska will move eastward
through northern MO and southern IA tonight.  The surface low will
drag a cold front southeastward through our forecast area late
tonight and Thursday morning.  Most of the models have the
precipitation north of the surface low track, although the ECMWF
model does generate light qpf across IL already this evening in the
warm air advection regime ahead of the shortwave.  The models were
also depicting upper level divergence centered over northeast MO and
west central IL, mainly late tonight in the left exit region of an
upper level jet streak dropping into southwest MO.  The quality and
depth of moisture is quite limited with this system so will only
include slight chance pops across west centrl and southwest IL,
mainly late tonight into Thursday morning.   A tight surface
pressure gradient along with a strong southwesterly low level jet
will lead to relatively strong surface winds for the nightime
hours.  Low temperatures will be above normal tonight as the strong
cold air advection behind the front will not impact most of the area
until Thursday morning.

GKS

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 402 PM CST Wed Jan 28 2015

Colder conditions are expected on Thursday due to low level cold air
advection with strong and gusty northwest winds behind the cold
front, along with post frontal low level cloudiness to limit solar
insolation.  Little diurnal temperature range is expected with some
areas likely having nearly steady or slightly falling temperatures
during the late morning and afternoon hours.  These clouds should
clear out Thursday night as subsidence increases over our area as a
strong surface ridge over the northern Plains builds southeastward
into the region.  Cold conditions will continue Thursday night and
Friday with near normal temperatures for late January.
Precipitation is expected to spread into our area by Saturday
afternoon and evening as moisture spreads into our region ahead of
the southwestern US upper level low, and as a strong northern stream
shortwave approaches from the northern Plains.  Initially it appears
that surface temperatures will be warm enough Saturday afternoon
into the evening that any precipiation at this time should fall as
liquid rain.  As a cold front sags southward through our forecast
area Saturday night into Sunday as the upper level trough gradually
deepens over the northern Plains and Great Lakes region the
precipitation should change over to snow.  The ECMWF model has most
of its QPF along and south of I-70 Saturday night and Sunday.  The
GFS is similar although it does have a little more qpf across
northern MO and west central IL compared to the ECMWF.  There has
been plenty of model differences along with run to run
inconsistencies with this weekend storm system and hence it has been
difficult to determine precipitation amounts and types across our
area.  For now it does appear that at least a portion of our
forecast area will see accumulating snow Saturday night and Sunday,
but the snowfall amounts and where the maximum axis of snow will
occur is still in question.  Much colder, below normal temperatures
can be expected for Sunday night through Monday night with the
models dropping the -12 degree C 850 mb isotherm southward into our
forecast area Sunday afternoon.  Monday and Tuesday will likely be
dry as snow associated with northwest flow shortwaves should be
north of our area, and any precipitation associated with the
southwest US upper level low finally moving eastward through the
southern Plains and Gulf Coast region will be well south of our area.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1137 AM CST Wed Jan 28 2015

VFR flight conditions are expected through this evening with winds
being the main issue. A tight pressure gradient ahead of an
approaching surface low and cold front will result in gusty
southeast winds this afternoon, which should diminish around or
just after sunset. Decoupling of the lower atmosphere after sunset
and the development of a stout south-southwesterly LLJ will
result in LLWS conditions for much of the evening and into the
overnight hours until the cold fropa. The cold front will move
through the TAF sites from northwest to southeast in the 08-12z
time frame accompanied by gusty northwest winds and MVFR flight
conditions.


Specifics for KSTL:

VFR flight conditions will persist this afternoon and evening with
gusty southeast winds into the early evening. The surface wind
will diminish during the evening and this will result in the onset
of LLWS as a stout south-southwest LLJ evolves. A strong cold
front will then move through the terminal in the 11-12z time frame
accompanied by gusty northwest winds and MVFR flight conditions.

Glass

&&

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

$$

WFO LSX








000
FXUS63 KLSX 282203
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
403 PM CST Wed Jan 28 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 402 PM CST Wed Jan 28 2015

Shortwave over the Nebraska panhandle and eastern CO and associated
surface low ahead of it over eastern Nebraska will move eastward
through northern MO and southern IA tonight.  The surface low will
drag a cold front southeastward through our forecast area late
tonight and Thursday morning.  Most of the models have the
precipitation north of the surface low track, although the ECMWF
model does generate light qpf across IL already this evening in the
warm air advection regime ahead of the shortwave.  The models were
also depicting upper level divergence centered over northeast MO and
west central IL, mainly late tonight in the left exit region of an
upper level jet streak dropping into southwest MO.  The quality and
depth of moisture is quite limited with this system so will only
include slight chance pops across west centrl and southwest IL,
mainly late tonight into Thursday morning.   A tight surface
pressure gradient along with a strong southwesterly low level jet
will lead to relatively strong surface winds for the nightime
hours.  Low temperatures will be above normal tonight as the strong
cold air advection behind the front will not impact most of the area
until Thursday morning.

GKS

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 402 PM CST Wed Jan 28 2015

Colder conditions are expected on Thursday due to low level cold air
advection with strong and gusty northwest winds behind the cold
front, along with post frontal low level cloudiness to limit solar
insolation.  Little diurnal temperature range is expected with some
areas likely having nearly steady or slightly falling temperatures
during the late morning and afternoon hours.  These clouds should
clear out Thursday night as subsidence increases over our area as a
strong surface ridge over the northern Plains builds southeastward
into the region.  Cold conditions will continue Thursday night and
Friday with near normal temperatures for late January.
Precipitation is expected to spread into our area by Saturday
afternoon and evening as moisture spreads into our region ahead of
the southwestern US upper level low, and as a strong northern stream
shortwave approaches from the northern Plains.  Initially it appears
that surface temperatures will be warm enough Saturday afternoon
into the evening that any precipiation at this time should fall as
liquid rain.  As a cold front sags southward through our forecast
area Saturday night into Sunday as the upper level trough gradually
deepens over the northern Plains and Great Lakes region the
precipitation should change over to snow.  The ECMWF model has most
of its QPF along and south of I-70 Saturday night and Sunday.  The
GFS is similar although it does have a little more qpf across
northern MO and west central IL compared to the ECMWF.  There has
been plenty of model differences along with run to run
inconsistencies with this weekend storm system and hence it has been
difficult to determine precipitation amounts and types across our
area.  For now it does appear that at least a portion of our
forecast area will see accumulating snow Saturday night and Sunday,
but the snowfall amounts and where the maximum axis of snow will
occur is still in question.  Much colder, below normal temperatures
can be expected for Sunday night through Monday night with the
models dropping the -12 degree C 850 mb isotherm southward into our
forecast area Sunday afternoon.  Monday and Tuesday will likely be
dry as snow associated with northwest flow shortwaves should be
north of our area, and any precipitation associated with the
southwest US upper level low finally moving eastward through the
southern Plains and Gulf Coast region will be well south of our area.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1137 AM CST Wed Jan 28 2015

VFR flight conditions are expected through this evening with winds
being the main issue. A tight pressure gradient ahead of an
approaching surface low and cold front will result in gusty
southeast winds this afternoon, which should diminish around or
just after sunset. Decoupling of the lower atmosphere after sunset
and the development of a stout south-southwesterly LLJ will
result in LLWS conditions for much of the evening and into the
overnight hours until the cold fropa. The cold front will move
through the TAF sites from northwest to southeast in the 08-12z
time frame accompanied by gusty northwest winds and MVFR flight
conditions.


Specifics for KSTL:

VFR flight conditions will persist this afternoon and evening with
gusty southeast winds into the early evening. The surface wind
will diminish during the evening and this will result in the onset
of LLWS as a stout south-southwest LLJ evolves. A strong cold
front will then move through the terminal in the 11-12z time frame
accompanied by gusty northwest winds and MVFR flight conditions.

Glass

&&

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

$$

WFO LSX







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