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000
FXUS63 KLSX 060534
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1134 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1124 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds have become SErly this evng on the
back side of the sfc ridge. Winds in the lowest few thousand feet
are expected to approach 35-40 kts towards 12Z but should remain
below LLWS criteria. A band of mid clouds is expected to signify
the passage of an upper lvl disturbance Fri mrng. Srly flow will
continue thru the prd with gusts near 20 kts possible tomorrow
late mrng/aftn.

Specifics for KSTL:

VFR fcst thru the prd with sthrly flow near 12kts drng the late
mrng/aftn.

2%

&&

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

$$

WFO LSX








000
FXUS63 KLSX 060534
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1134 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1124 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds have become SErly this evng on the
back side of the sfc ridge. Winds in the lowest few thousand feet
are expected to approach 35-40 kts towards 12Z but should remain
below LLWS criteria. A band of mid clouds is expected to signify
the passage of an upper lvl disturbance Fri mrng. Srly flow will
continue thru the prd with gusts near 20 kts possible tomorrow
late mrng/aftn.

Specifics for KSTL:

VFR fcst thru the prd with sthrly flow near 12kts drng the late
mrng/aftn.

2%

&&

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

$$

WFO LSX







000
FXUS63 KLSX 060534
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1134 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1124 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds have become SErly this evng on the
back side of the sfc ridge. Winds in the lowest few thousand feet
are expected to approach 35-40 kts towards 12Z but should remain
below LLWS criteria. A band of mid clouds is expected to signify
the passage of an upper lvl disturbance Fri mrng. Srly flow will
continue thru the prd with gusts near 20 kts possible tomorrow
late mrng/aftn.

Specifics for KSTL:

VFR fcst thru the prd with sthrly flow near 12kts drng the late
mrng/aftn.

2%

&&

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

$$

WFO LSX








000
FXUS63 KLSX 060534
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1134 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1124 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds have become SErly this evng on the
back side of the sfc ridge. Winds in the lowest few thousand feet
are expected to approach 35-40 kts towards 12Z but should remain
below LLWS criteria. A band of mid clouds is expected to signify
the passage of an upper lvl disturbance Fri mrng. Srly flow will
continue thru the prd with gusts near 20 kts possible tomorrow
late mrng/aftn.

Specifics for KSTL:

VFR fcst thru the prd with sthrly flow near 12kts drng the late
mrng/aftn.

2%

&&

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

$$

WFO LSX







000
FXUS63 KLSX 060030
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
630 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 611 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds will be lght/vrb this evng as the sfc
ridge axis passes...bcmng srly by Fri mrng. SW winds in the lowest
few thousand feet increase to nearly 40kts towards 12Z across
cntrl/NE MO and w cntrl IL but is expected to remain below LLWS
criteria attm. A band of mid lvl clouds is expected to accompany
an upper lvl disturbance Fri mrng with the greatest coverage
expected across nthrn MO into cntrl IL. Fri aftn should feature
clear skies and a S/SW breeze at 10-15kts...later shifts may need
to include gusts.

Specifics for KSTL:

VFR fcst thru the prd with lght/vrb wind this evng bcmng S/SSW Fri
mrng.

2%

&&

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

$$

WFO LSX








000
FXUS63 KLSX 060030
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
630 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 611 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds will be lght/vrb this evng as the sfc
ridge axis passes...bcmng srly by Fri mrng. SW winds in the lowest
few thousand feet increase to nearly 40kts towards 12Z across
cntrl/NE MO and w cntrl IL but is expected to remain below LLWS
criteria attm. A band of mid lvl clouds is expected to accompany
an upper lvl disturbance Fri mrng with the greatest coverage
expected across nthrn MO into cntrl IL. Fri aftn should feature
clear skies and a S/SW breeze at 10-15kts...later shifts may need
to include gusts.

Specifics for KSTL:

VFR fcst thru the prd with lght/vrb wind this evng bcmng S/SSW Fri
mrng.

2%

&&

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

$$

WFO LSX







000
FXUS63 KLSX 060030
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
630 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 611 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds will be lght/vrb this evng as the sfc
ridge axis passes...bcmng srly by Fri mrng. SW winds in the lowest
few thousand feet increase to nearly 40kts towards 12Z across
cntrl/NE MO and w cntrl IL but is expected to remain below LLWS
criteria attm. A band of mid lvl clouds is expected to accompany
an upper lvl disturbance Fri mrng with the greatest coverage
expected across nthrn MO into cntrl IL. Fri aftn should feature
clear skies and a S/SW breeze at 10-15kts...later shifts may need
to include gusts.

Specifics for KSTL:

VFR fcst thru the prd with lght/vrb wind this evng bcmng S/SSW Fri
mrng.

2%

&&

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

$$

WFO LSX








000
FXUS63 KLSX 060030
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
630 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 611 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds will be lght/vrb this evng as the sfc
ridge axis passes...bcmng srly by Fri mrng. SW winds in the lowest
few thousand feet increase to nearly 40kts towards 12Z across
cntrl/NE MO and w cntrl IL but is expected to remain below LLWS
criteria attm. A band of mid lvl clouds is expected to accompany
an upper lvl disturbance Fri mrng with the greatest coverage
expected across nthrn MO into cntrl IL. Fri aftn should feature
clear skies and a S/SW breeze at 10-15kts...later shifts may need
to include gusts.

Specifics for KSTL:

VFR fcst thru the prd with lght/vrb wind this evng bcmng S/SSW Fri
mrng.

2%

&&

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

$$

WFO LSX







000
FXUS63 KLSX 052101
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
301 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 052101
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
301 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 052101
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
301 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 052101
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
301 PM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 250 PM CST Thu Mar 5 2015

Another cold night is expected across the region. High pressure
currently centered through the Mid MS Valley will gradually
retreat eastward tonight with southerly winds and low level warm
advection developing in its wake. The impacts of this will be most
pronounced across the western part of the CWA where southerly
winds will develop by late evening. Meanwhile a well-defined
short wave trof currently moving through the north central Plains
will also dig into the area overnight bringing an increase in mid-
high clouds to primarily northern parts of the CWA. The result
will be the coldest temperatures tonight will be across the
deepest snow cover and where winds remain light longest which will
be southeast MO and southern IL. This is where I have dropped
temperatures a good deal from the previous forecast with mins in
the single digits to just below zero. Another area with a decent
drop will be across parts of northeast MO into west central IL,
again coincident with snow cover. This area however will see warm
advection and clouds overnight keeping mins more in check than the
frigid south.

Glass

.LONG TERM:  (Friday through Next Thursday)
Issued at 250 PM CST Thu Mar 5 2015

Friday through this weekend will feature moderating temperatures
with near average temperatures over the weekend. The prominent
eastern NOAM longwave trof will weaken some but west-northwest
flow will persist. Embedded within this flow will be several
shortwaves which will bring weak cold fronts through the area
Saturday afternoon/evening and again Sunday night. Impacts of
these will be minor and any cooling will be short-lived.

The real warm-up will commence next week coinciding with a marked
pattern change. The eastern longwave will shift northeastward and
migrate into the north Atlantic bringing a northward retreat of
the polar jet to the vicinity of the U.S./Canadian border.
Troffing aloft will persist from the southern Plains into Mexico
however heights aloft through the Nation`s midsection will be
seasonable. This will result in benign/tranquil weather, persistent
low level southwesterly flow and warm advection and above average
temperatures Tuesday through Thursday.

Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 051827
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1227 PM CST Thu Mar 5 2015

.UPDATE:
Issued at 1225 PM CST Thu Mar 5 2015

Going forecast by and large still looks on track for the rest of
the afternoon. Only change of note was to increase temperatures a
couple of degrees, particularly for areas with little to no snow
cover...i.e., for portions of central and east-central Missouri
including the Columbia and St. Louis metro areas.

Gosselin

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 051827
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1227 PM CST Thu Mar 5 2015

.UPDATE:
Issued at 1225 PM CST Thu Mar 5 2015

Going forecast by and large still looks on track for the rest of
the afternoon. Only change of note was to increase temperatures a
couple of degrees, particularly for areas with little to no snow
cover...i.e., for portions of central and east-central Missouri
including the Columbia and St. Louis metro areas.

Gosselin

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 051743
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1143 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 051743
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1143 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 051743
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1143 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX







000
FXUS63 KLSX 051743
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1143 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1140 AM CST Thu Mar 5 2015

Some diurnal cu to affect the metro terminals through early this
afternoon. Otherwise...mostly clear skies through tonight with
winds becoming light/variable this evening. Winds will turn to the
southeast by Friday morning and pick up to between 10 and 15
knots.


Specifics for KSTL:

Some diurnal cu to affect terminal through early this
afternoon...but stay within VFR. A mostly clear sky will develop
by early this evening along with winds becoming light/variable.
Winds will turn to the southeast by Friday morning and pick up to
between 10 and 15 knots fore becoming southerly by around noon on Friday.

Gosselin

&&

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

$$

WFO LSX








000
FXUS63 KLSX 051030
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
430 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Friday Morning)
Issued at 430 AM CST Thu Mar 5 2015

VFR conditions will prevail at the TAF sites thru much of the
valid period. Only concern is a small stubborn area of low CIGs
that continues to snake its way down into northeast MO. There are
also some flurries in this area. Low level flow would encourage
this area of clouds/flurries to move SSE but the weak lift that
seems to have generated it in the first place looks set to weaken
with time and so there is some measure of doubt how far south this
will go. Will add some scattered clouds in and watch closely the
next few hours. Otherwise, look for northerly surface winds to
become light and variable by sundown and then from the SE later
tonight.

Specifics for KSTL: VFR thru the period. Only questionable item is
how well will small area of low CIGs and some flurries hold
together as they are expected to drop SSE thru eastern-central MO.
Will maintain scattered cloud coverage for now and continue to
monitor considering what generated them in the first place is
expected to weaken. Otherwise, winds will be the main driver of
new TAF line groups as they go from N to light to SE.

TES

&&

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

$$

WFO LSX





000
FXUS63 KLSX 051030
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
430 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Friday Morning)
Issued at 430 AM CST Thu Mar 5 2015

VFR conditions will prevail at the TAF sites thru much of the
valid period. Only concern is a small stubborn area of low CIGs
that continues to snake its way down into northeast MO. There are
also some flurries in this area. Low level flow would encourage
this area of clouds/flurries to move SSE but the weak lift that
seems to have generated it in the first place looks set to weaken
with time and so there is some measure of doubt how far south this
will go. Will add some scattered clouds in and watch closely the
next few hours. Otherwise, look for northerly surface winds to
become light and variable by sundown and then from the SE later
tonight.

Specifics for KSTL: VFR thru the period. Only questionable item is
how well will small area of low CIGs and some flurries hold
together as they are expected to drop SSE thru eastern-central MO.
Will maintain scattered cloud coverage for now and continue to
monitor considering what generated them in the first place is
expected to weaken. Otherwise, winds will be the main driver of
new TAF line groups as they go from N to light to SE.

TES

&&

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

$$

WFO LSX






000
FXUS63 KLSX 050946
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
346 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015

Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.

Specifics for KSTL:

VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.

2%

&&

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

$$

WFO LSX







000
FXUS63 KLSX 050946
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
346 AM CST Thu Mar 5 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 344 AM CST Thu Mar 5 2015

An upper level TROF axis extends from MN to central KS early this
morning with a W-SW flow resulting over our region.  Canadian high
pressure was centered over the Mid-MO river valley.  The primary
cold front is well to our south, near the Gulf of Mexico coastline,
and there appears to be a weak secondary cold front pushing thru
northern MO and central IL now as evidenced by some pressure rises,
a lull in the winds, and a reinforcing shot of CAA.  Some weak lift,
either from this or from something immediately following the front,
also seems responsible for additional clouds and patchy light snow
in IA.  Temps were in the teens and lower 20s across our region with
no precipitation (for the moment).

The upper level TROF axis is expected to swing thru by early this
afternoon leaving behind NW flow aloft in its wake.  The weak lift,
which seems to be shown best on the GFS model, tracks southeastward
towards the Quincy area this morning before its various component
parts split apart by midday off to our east and southeast.  The
atmospheric column is very dry already and so we do not expect much
more than scattered flurries for some areas in northeast MO and into
west-central IL, with an isolated heavier snow shower possible but
the coverage of which is not significant enough to account for in
the forecast at this time as there are some doubts as to how well
even the scattered flurries will hold up as they try to move
southeast.  Either way, it looks to all be gone by early afternoon.
This area of lift will also bring some extra clouds into the area as
well and delay our full clearing until later in the day.

Otherwise, it will be a very cold day today, with max temps not
expected to exceed the mid 20s, with readings remaining in the teens
for many areas north and northeast of STL metro.  A MOS blend was
used for most sites.  This will result in temps being about 30
degrees below the norm for this time of year.

TES

.LONG TERM: (Tonight through Wednesday)
Issued at 344 AM CST Thu Mar 5 2015

Tonight will be unseasonably cold again, particularly across
southeast MO and southwest IL near the surface ridge axis with good
radiational cooling expected.  Will go below MOS temperature
guidance, especially in areas with snow cover.  Temperatures across
northeast and central MO will fall this evening, but should become
nearly steady or rise slightly late tonight as surface winds become
southerly on the west or northwest side of the surface ridge, and as
low level warm air advection increases over this area.  A northwest
flow shortwave will move southeastward through northeast MO and west
central IL late tonight.  There may be a little cloud cover ahead of
this feature, but it will be too dry for any precipitation.  Friday
will be the start of a warming trend as surface south-southwesterly
flow becomes established across the area.  The models shift the zero
degree C 850 mb isotherm eastward to the Mississippi River by 00Z
Saturday.  Temperatures by Friday night should be near normal for
early March, and eventually above normal by Saturday.  The NAM model
generates some very light qpf Saturday night across IL ahead of a
northwest flow shortwave, but this is likely more of a reflection of
boundary layer moisture and possible low level cloudiness and not
likely any light precipitation.  A weak and dissipating cold front
will drop southeastward into our area Saturday night.  Little if
any cooling is expected behind the front, maybe a few degrees cooler
across northeast MO and west central IL, but most areas will
continue to have above normal temperatures for the remainder of the
weekend.  The dry and tranquil weather pattern will continue for the
next work week with surface ridging across our area on Monday.  Even
warmer temperatures are expected for Tuesday and Wednesday with any
precipitation remaining south and southeast of our forecast area
ahead of a southern stream upper level trough and assoociated
surface low.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015

Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.

Specifics for KSTL:

VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.

2%

&&

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

$$

WFO LSX








000
FXUS63 KLSX 050602
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1202 AM CST Thu Mar 5 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015

Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.

Specifics for KSTL:

VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 050602
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1202 AM CST Thu Mar 5 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015

Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.

Specifics for KSTL:

VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 050602
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1202 AM CST Thu Mar 5 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015

Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.

Specifics for KSTL:

VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 050602
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1202 AM CST Thu Mar 5 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015

Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.

Specifics for KSTL:

VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 050301
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
901 PM CST Wed Mar 4 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 540 PM CST Wed Mar 4 2015

Ongoing storm system affecting the sthrn Plains NE into the OH vly
will remain south of the terminals overnight. Widespread mid/high
clouds will continue to stream NE this evng Skies should clear
either late tonight or early Thu mrng as the storm system moves
east. Some model guidance is suggesting an area of
stratus...possibly below 1kft...dropping out of IA towards 12Z.
Not confident in this solution...therefore have not included any
mention of low clouds attm. Otherwise...N/NW winds around 10kts
and clear skies.

Specifics for KSTL:

Mid/high clouds will continue to stream overhead thru the
night...finally pushing east towards 12Z. Models are hinting at a
small area of stratus dropping south along the MS rvr Thu mrng
but to not have enough confidence in that solution to include
mention attm. Otherwise expect N/NW wind around 10kts and clear
skies. Winds should go lght/vrb tomorrow evng as sfc ridge passes.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX







000
FXUS63 KLSX 050301
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
901 PM CST Wed Mar 4 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 540 PM CST Wed Mar 4 2015

Ongoing storm system affecting the sthrn Plains NE into the OH vly
will remain south of the terminals overnight. Widespread mid/high
clouds will continue to stream NE this evng Skies should clear
either late tonight or early Thu mrng as the storm system moves
east. Some model guidance is suggesting an area of
stratus...possibly below 1kft...dropping out of IA towards 12Z.
Not confident in this solution...therefore have not included any
mention of low clouds attm. Otherwise...N/NW winds around 10kts
and clear skies.

Specifics for KSTL:

Mid/high clouds will continue to stream overhead thru the
night...finally pushing east towards 12Z. Models are hinting at a
small area of stratus dropping south along the MS rvr Thu mrng
but to not have enough confidence in that solution to include
mention attm. Otherwise expect N/NW wind around 10kts and clear
skies. Winds should go lght/vrb tomorrow evng as sfc ridge passes.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 050301
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
901 PM CST Wed Mar 4 2015

.UPDATE:
Issued at 856 PM CST Wed Mar 4 2015

There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.

Kanofsky

&&

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 540 PM CST Wed Mar 4 2015

Ongoing storm system affecting the sthrn Plains NE into the OH vly
will remain south of the terminals overnight. Widespread mid/high
clouds will continue to stream NE this evng Skies should clear
either late tonight or early Thu mrng as the storm system moves
east. Some model guidance is suggesting an area of
stratus...possibly below 1kft...dropping out of IA towards 12Z.
Not confident in this solution...therefore have not included any
mention of low clouds attm. Otherwise...N/NW winds around 10kts
and clear skies.

Specifics for KSTL:

Mid/high clouds will continue to stream overhead thru the
night...finally pushing east towards 12Z. Models are hinting at a
small area of stratus dropping south along the MS rvr Thu mrng
but to not have enough confidence in that solution to include
mention attm. Otherwise expect N/NW wind around 10kts and clear
skies. Winds should go lght/vrb tomorrow evng as sfc ridge passes.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO.

IL...NONE.
&&

$$

WFO LSX








000
FXUS63 KLSX 050031
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
631 PM CST Wed Mar 4 2015

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 540 PM CST Wed Mar 4 2015

Ongoing storm system affecting the sthrn Plains NE into the OH vly
will remain south of the terminals overnight. Widespread mid/high
clouds will continue to stream NE this evng Skies should clear
either late tonight or early Thu mrng as the storm system moves
east. Some model guidance is suggesting an area of
stratus...possibly below 1kft...dropping out of IA towards 12Z.
Not confident in this solution...therefore have not included any
mention of low clouds attm. Otherwise...N/NW winds around 10kts
and clear skies.

Specifics for KSTL:

Mid/high clouds will continue to stream overhead thru the
night...finally pushing east towards 12Z. Models are hinting at a
small area of stratus dropping south along the MS rvr Thu mrng
but to not have enough confidence in that solution to include
mention attm. Otherwise expect N/NW wind around 10kts and clear
skies. Winds should go lght/vrb tomorrow evng as sfc ridge passes.

2%

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     11  22  11  38 /  10   5   0   0
Quincy           4  17  10  39 /   5   0   0   0
Columbia        12  24  14  44 /  10   5   0   0
Jefferson City  13  25  14  44 /  10   5   0   0
Salem           12  19   3  31 /  30   5   0   0
Farmington      12  24   5  34 /  60  10   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 050031
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
631 PM CST Wed Mar 4 2015

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 540 PM CST Wed Mar 4 2015

Ongoing storm system affecting the sthrn Plains NE into the OH vly
will remain south of the terminals overnight. Widespread mid/high
clouds will continue to stream NE this evng Skies should clear
either late tonight or early Thu mrng as the storm system moves
east. Some model guidance is suggesting an area of
stratus...possibly below 1kft...dropping out of IA towards 12Z.
Not confident in this solution...therefore have not included any
mention of low clouds attm. Otherwise...N/NW winds around 10kts
and clear skies.

Specifics for KSTL:

Mid/high clouds will continue to stream overhead thru the
night...finally pushing east towards 12Z. Models are hinting at a
small area of stratus dropping south along the MS rvr Thu mrng
but to not have enough confidence in that solution to include
mention attm. Otherwise expect N/NW wind around 10kts and clear
skies. Winds should go lght/vrb tomorrow evng as sfc ridge passes.

2%

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     11  22  11  38 /  10   5   0   0
Quincy           4  17  10  39 /   5   0   0   0
Columbia        12  24  14  44 /  10   5   0   0
Jefferson City  13  25  14  44 /  10   5   0   0
Salem           12  19   3  31 /  30   5   0   0
Farmington      12  24   5  34 /  60  10   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 042018
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
218 PM CST Wed Mar 4 2015

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1204 PM CST Wed Mar 4 2015

VFR cigs to persist at KCOU and KUIN while metro area tafs to deal
with a few more hours of MVFR cigs and vsbys from time to time
with the light snow before tapering off. Otherwise, winds to
remain from the north through the forecast period.

Specifics for KSTL:
Metro area to deal with a few more hours of MVFR cigs and vsbys
from time to time with the light snow before tapering off after
20z Wednesday. Otherwise, winds to remain from the north through the
forecast period.

Byrd

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     11  22  11  37 /  20   5   0   0
Quincy           4  17  10  38 /   5   0   0   0
Columbia        12  24  14  43 /  10   5   0   0
Jefferson City  13  25  14  43 /  10   5   0   0
Salem           12  19   3  30 /  40   5   0   0
Farmington      12  24   5  33 /  60  10   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 042018
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
218 PM CST Wed Mar 4 2015

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1204 PM CST Wed Mar 4 2015

VFR cigs to persist at KCOU and KUIN while metro area tafs to deal
with a few more hours of MVFR cigs and vsbys from time to time
with the light snow before tapering off. Otherwise, winds to
remain from the north through the forecast period.

Specifics for KSTL:
Metro area to deal with a few more hours of MVFR cigs and vsbys
from time to time with the light snow before tapering off after
20z Wednesday. Otherwise, winds to remain from the north through the
forecast period.

Byrd

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     11  22  11  37 /  20   5   0   0
Quincy           4  17  10  38 /   5   0   0   0
Columbia        12  24  14  43 /  10   5   0   0
Jefferson City  13  25  14  43 /  10   5   0   0
Salem           12  19   3  30 /  40   5   0   0
Farmington      12  24   5  33 /  60  10   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 042018
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
218 PM CST Wed Mar 4 2015

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1204 PM CST Wed Mar 4 2015

VFR cigs to persist at KCOU and KUIN while metro area tafs to deal
with a few more hours of MVFR cigs and vsbys from time to time
with the light snow before tapering off. Otherwise, winds to
remain from the north through the forecast period.

Specifics for KSTL:
Metro area to deal with a few more hours of MVFR cigs and vsbys
from time to time with the light snow before tapering off after
20z Wednesday. Otherwise, winds to remain from the north through the
forecast period.

Byrd

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     11  22  11  37 /  20   5   0   0
Quincy           4  17  10  38 /   5   0   0   0
Columbia        12  24  14  43 /  10   5   0   0
Jefferson City  13  25  14  43 /  10   5   0   0
Salem           12  19   3  30 /  40   5   0   0
Farmington      12  24   5  33 /  60  10   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 042018
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
218 PM CST Wed Mar 4 2015

.SHORT TERM:  (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015

All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry  with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.

Byrd

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015

(Thursday through Saturday)

Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.

Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.

(Sunday through Wednesday)

Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.

Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.

Tilly

&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1204 PM CST Wed Mar 4 2015

VFR cigs to persist at KCOU and KUIN while metro area tafs to deal
with a few more hours of MVFR cigs and vsbys from time to time
with the light snow before tapering off. Otherwise, winds to
remain from the north through the forecast period.

Specifics for KSTL:
Metro area to deal with a few more hours of MVFR cigs and vsbys
from time to time with the light snow before tapering off after
20z Wednesday. Otherwise, winds to remain from the north through the
forecast period.

Byrd

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     11  22  11  37 /  20   5   0   0
Quincy           4  17  10  38 /   5   0   0   0
Columbia        12  24  14  43 /  10   5   0   0
Jefferson City  13  25  14  43 /  10   5   0   0
Salem           12  19   3  30 /  40   5   0   0
Farmington      12  24   5  33 /  60  10   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 041807
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1207 PM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES
&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1204 PM CST Wed Mar 4 2015

VFR cigs to persist at KCOU and KUIN while metro area tafs to deal
with a few more hours of MVFR cigs and vsbys from time to time
with the light snow before tapering off. Otherwise, winds to
remain from the north through the forecast period.

Specifics for KSTL:
Metro area to deal with a few more hours of MVFR cigs and vsbys
from time to time with the light snow before tapering off after
20z Wednesday. Otherwise, winds to remain from the north through the
forecast period.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 041807
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1207 PM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES
&&

.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1204 PM CST Wed Mar 4 2015

VFR cigs to persist at KCOU and KUIN while metro area tafs to deal
with a few more hours of MVFR cigs and vsbys from time to time
with the light snow before tapering off. Otherwise, winds to
remain from the north through the forecast period.

Specifics for KSTL:
Metro area to deal with a few more hours of MVFR cigs and vsbys
from time to time with the light snow before tapering off after
20z Wednesday. Otherwise, winds to remain from the north through the
forecast period.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 041130
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
530 AM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES

&&

.AVIATION:  (For the 12z TAFs through 12z Thursday Morning)
Issued at 530 AM CST Wed Mar 4 2015

Snow will move in for a few hours into the I-70 TAF locations
for a period this morning. While some erosion of the snow
currently over central-western MO is expected on its northern
side, it should still be enough to result in decent VSBY
reductions, and probably into IFR category for most. By midday or
early afternoon, the snow threat should be to the south with just
dry wx and VFR conditions the remainder of the way with a steady
wind from the north. Speaking of winds, the strongest and gustiest
winds are expected now along I-70 with the main cold push and
should diminish a bit later this morning.

Specifics for KSTL: A few flurries expected until later this
morning when the main push of snow will occur for a few hours and
will likely continue into early afternoon. VSBY reductions into
MVFR expected, and IFR a possibility depending on how well the
northern edge erodes on its approach. Otherwise, VFR and north
winds from about 19z onward.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX





000
FXUS63 KLSX 041130
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
530 AM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES

&&

.AVIATION:  (For the 12z TAFs through 12z Thursday Morning)
Issued at 530 AM CST Wed Mar 4 2015

Snow will move in for a few hours into the I-70 TAF locations
for a period this morning. While some erosion of the snow
currently over central-western MO is expected on its northern
side, it should still be enough to result in decent VSBY
reductions, and probably into IFR category for most. By midday or
early afternoon, the snow threat should be to the south with just
dry wx and VFR conditions the remainder of the way with a steady
wind from the north. Speaking of winds, the strongest and gustiest
winds are expected now along I-70 with the main cold push and
should diminish a bit later this morning.

Specifics for KSTL: A few flurries expected until later this
morning when the main push of snow will occur for a few hours and
will likely continue into early afternoon. VSBY reductions into
MVFR expected, and IFR a possibility depending on how well the
northern edge erodes on its approach. Otherwise, VFR and north
winds from about 19z onward.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX






000
FXUS63 KLSX 041130
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
530 AM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES

&&

.AVIATION:  (For the 12z TAFs through 12z Thursday Morning)
Issued at 530 AM CST Wed Mar 4 2015

Snow will move in for a few hours into the I-70 TAF locations
for a period this morning. While some erosion of the snow
currently over central-western MO is expected on its northern
side, it should still be enough to result in decent VSBY
reductions, and probably into IFR category for most. By midday or
early afternoon, the snow threat should be to the south with just
dry wx and VFR conditions the remainder of the way with a steady
wind from the north. Speaking of winds, the strongest and gustiest
winds are expected now along I-70 with the main cold push and
should diminish a bit later this morning.

Specifics for KSTL: A few flurries expected until later this
morning when the main push of snow will occur for a few hours and
will likely continue into early afternoon. VSBY reductions into
MVFR expected, and IFR a possibility depending on how well the
northern edge erodes on its approach. Otherwise, VFR and north
winds from about 19z onward.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX





000
FXUS63 KLSX 040926
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
326 AM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1100 PM CST Tue Mar 3 2015

KCOU AND KUIN TAF sites will see MVFR ceilings until around 12Z.
VFR ceilings thereafter as drier air filters in with another
arctic airmass. Northwest winds will increase and then become
gusty after daybreak at all TAF sites. KSTL area TAF sites will
experience IFR visibilities at times for the first several hours
as rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Specifics for KSTL: Northwest winds will increase and then become
gusty after daybreak as arctic airmass moves into the region.
Expect IFR visibilities at times for the first several hours as
rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 040926
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
326 AM CST Wed Mar 4 2015

.SHORT TERM: (Through Friday night)
Issued at 324 AM CST Wed Mar 4 2015

Rain with embedded sleet was moving across southeast MO and
southwest IL early this morning.  Starting to get a light rain and
sleet mix in the St Louis metro area.  The latest AMDARS sounding
had an elevated warm layer at 850 mb of up to 3-4 degrees C.  As the
strong surface ridge across the northern Plains builds southeastward
into our area the cold surface layer will deepen and the elevated
warm layer will shrink with time.  Much of the current precipitation
on radar will shift east of our forecast area early this morning,
but another batch of precipitation will move through southeast MO
and southwest IL, mainly south of STL late this morning and this
afternoon as a positively tilted upper level trough approaches.  The
models depict increasing upper level divergence across southeast MO
and southern IL in the right entrance region of a strong upper level
jet streak over the Great Lakes region.  The best mid level warm air
advection/isentropic lift and frontogenesis will remain across the
extreme southern portion of our forecast area today.  Precipitation
type per thickness forecasts and model forecast soundings would
suggest snow along I-70 this morning with a mix of sleet and
freezing rain across most of southeast MO and southwest IL.  By noon
there should be a mix of snow and sleet across southeast MO and
southwest IL, and by late afternoon it should be all snow.
Temperatures today will likely be nearly steady across northeast and
central MO, and slowly falling elsewhere due to strong low level
cold air advection along with low level cloud cover and
precipitation across the south or southeast half of the forecast
area.  Should get up to one tenth of an inch of ice across portions
of southeast MO this morning.  Total snow and sleet accumulations
today and tonight will range from around 1 inch in STL to near
6 inches across portions of southeast MO.  Will continue the winter
storm warning across a small portion of southeast MO and southwest
IL with a winter weather advisory extending north to almost the city
of St Louis.  Snow will linger across parts of southeast MO and
southwest IL this evening, but should shift southeast of our
forecast area late tonight as the positively tilted upper level
trough moves eastward through our area, while the strong surface
ridge continues to build southeastward into MO.  Unseasonably cold
temperatures can be expected tonight and Thursday with the models
dropping the -16 degree C 850 mb istotherm southward to around STL
bt 12Z Thursday.  The coldest temperatures Thursday night should be
across parts of southeast MO and southwest IL underneath the surface
ridge axis with good radiational cooling.  Surface winds will become
southerly across northeast and central MO on the west/northwest side
of the surface ridge Thursday night.  Much warmer temperatures can
be expected for Friday and Friday night, albeit still at least a
little below normal for early March.

GKS

.LONG TERM: (Saturday through Tuesday)
Issued at 324 AM CST Wed Mar 4 2015

Northwest flow aloft, absent any significant disturbances of note,
will dominate this period coupled with a persistent southerly flow
at the surface.  The end result will be a period of little to no
precipitation and temperatures that are at or above average for
early March, with daytime max temps in at least the 60s by early
next week.

TES

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1100 PM CST Tue Mar 3 2015

KCOU AND KUIN TAF sites will see MVFR ceilings until around 12Z.
VFR ceilings thereafter as drier air filters in with another
arctic airmass. Northwest winds will increase and then become
gusty after daybreak at all TAF sites. KSTL area TAF sites will
experience IFR visibilities at times for the first several hours
as rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Specifics for KSTL: Northwest winds will increase and then become
gusty after daybreak as arctic airmass moves into the region.
Expect IFR visibilities at times for the first several hours as
rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Crawford
     MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
     Madison MO-Reynolds MO-St. Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Clinton
     IL-Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING until Midnight CST tonight FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 040518
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1118 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1100 PM CST Tue Mar 3 2015

KCOU AND KUIN TAF sites will see MVFR ceilings until around 12Z.
VFR ceilings thereafter as drier air filters in with another
arctic airmass. Northwest winds will increase and then become
gusty after daybreak at all TAF sites. KSTL area TAF sites will
experience IFR visibilities at times for the first several hours
as rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Specifics for KSTL: Northwest winds will increase and then become
gusty after daybreak as arctic airmass moves into the region.
Expect IFR visibilities at times for the first several hours as
rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 040518
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1118 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1100 PM CST Tue Mar 3 2015

KCOU AND KUIN TAF sites will see MVFR ceilings until around 12Z.
VFR ceilings thereafter as drier air filters in with another
arctic airmass. Northwest winds will increase and then become
gusty after daybreak at all TAF sites. KSTL area TAF sites will
experience IFR visibilities at times for the first several hours
as rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Specifics for KSTL: Northwest winds will increase and then become
gusty after daybreak as arctic airmass moves into the region.
Expect IFR visibilities at times for the first several hours as
rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 040518
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1118 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1100 PM CST Tue Mar 3 2015

KCOU AND KUIN TAF sites will see MVFR ceilings until around 12Z.
VFR ceilings thereafter as drier air filters in with another
arctic airmass. Northwest winds will increase and then become
gusty after daybreak at all TAF sites. KSTL area TAF sites will
experience IFR visibilities at times for the first several hours
as rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Specifics for KSTL: Northwest winds will increase and then become
gusty after daybreak as arctic airmass moves into the region.
Expect IFR visibilities at times for the first several hours as
rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 040518
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1118 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1100 PM CST Tue Mar 3 2015

KCOU AND KUIN TAF sites will see MVFR ceilings until around 12Z.
VFR ceilings thereafter as drier air filters in with another
arctic airmass. Northwest winds will increase and then become
gusty after daybreak at all TAF sites. KSTL area TAF sites will
experience IFR visibilities at times for the first several hours
as rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Specifics for KSTL: Northwest winds will increase and then become
gusty after daybreak as arctic airmass moves into the region.
Expect IFR visibilities at times for the first several hours as
rain, possibly mixed with some sleet at times, moves over the
region. Otherwise expect MVFR visibilities, with precip changing
to light snow by around 10Z. Precip should end by around 16Z.
Ceilings will remain in the MVFR range through around 16Z then
improve to VFR.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 040454
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1054 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 546 PM CST Tue Mar 3 2015

MVFR ceilings will last through much of the night at all TAF
sites as cold front pushes through and stratus deck remains. KUIN
and KCOU will likely be VFR by 10-13Z Wednesday, then VFR ceilings
reach KSTL TAF sites by around 16Z. Will have to watch radar and
surface reports carefully this evening as there is some chance
that precip aloft now seen on regional radars may reach the surface at
KSTL area TAF sites. For now, it appears a dry layer at 6K to 8K
feet may keep this from happening so have left TAFS dry. Northwest
winds behind the front will become gusty and last into Wednesday.

Specifics for KSTL: MVFR ceilings expected until 16Z. Cold front
should reach TAF site by around 06Z, and north winds behind the
cold front will increase to around 14 knots and become gusty.
Have kept TAF dry for now, but will have to watch surface reports
to see if precip aloft now seen on radar begins reaching the
ground this evening. Expect dry air aloft to keep most precip just
to the south of KSTL on Wednesday, but it is a close call.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 040454
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1054 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 546 PM CST Tue Mar 3 2015

MVFR ceilings will last through much of the night at all TAF
sites as cold front pushes through and stratus deck remains. KUIN
and KCOU will likely be VFR by 10-13Z Wednesday, then VFR ceilings
reach KSTL TAF sites by around 16Z. Will have to watch radar and
surface reports carefully this evening as there is some chance
that precip aloft now seen on regional radars may reach the surface at
KSTL area TAF sites. For now, it appears a dry layer at 6K to 8K
feet may keep this from happening so have left TAFS dry. Northwest
winds behind the front will become gusty and last into Wednesday.

Specifics for KSTL: MVFR ceilings expected until 16Z. Cold front
should reach TAF site by around 06Z, and north winds behind the
cold front will increase to around 14 knots and become gusty.
Have kept TAF dry for now, but will have to watch surface reports
to see if precip aloft now seen on radar begins reaching the
ground this evening. Expect dry air aloft to keep most precip just
to the south of KSTL on Wednesday, but it is a close call.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 040454
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1054 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 546 PM CST Tue Mar 3 2015

MVFR ceilings will last through much of the night at all TAF
sites as cold front pushes through and stratus deck remains. KUIN
and KCOU will likely be VFR by 10-13Z Wednesday, then VFR ceilings
reach KSTL TAF sites by around 16Z. Will have to watch radar and
surface reports carefully this evening as there is some chance
that precip aloft now seen on regional radars may reach the surface at
KSTL area TAF sites. For now, it appears a dry layer at 6K to 8K
feet may keep this from happening so have left TAFS dry. Northwest
winds behind the front will become gusty and last into Wednesday.

Specifics for KSTL: MVFR ceilings expected until 16Z. Cold front
should reach TAF site by around 06Z, and north winds behind the
cold front will increase to around 14 knots and become gusty.
Have kept TAF dry for now, but will have to watch surface reports
to see if precip aloft now seen on radar begins reaching the
ground this evening. Expect dry air aloft to keep most precip just
to the south of KSTL on Wednesday, but it is a close call.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 040454
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1054 PM CST Tue Mar 3 2015

.UPDATE:
Issued at 1053 PM CST Tue Mar 3 2015

Latest RAP soundings delay the precip changeover by a couple of
hours. Updated grids and products have been sent.

Kanofsky

&&

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 546 PM CST Tue Mar 3 2015

MVFR ceilings will last through much of the night at all TAF
sites as cold front pushes through and stratus deck remains. KUIN
and KCOU will likely be VFR by 10-13Z Wednesday, then VFR ceilings
reach KSTL TAF sites by around 16Z. Will have to watch radar and
surface reports carefully this evening as there is some chance
that precip aloft now seen on regional radars may reach the surface at
KSTL area TAF sites. For now, it appears a dry layer at 6K to 8K
feet may keep this from happening so have left TAFS dry. Northwest
winds behind the front will become gusty and last into Wednesday.

Specifics for KSTL: MVFR ceilings expected until 16Z. Cold front
should reach TAF site by around 06Z, and north winds behind the
cold front will increase to around 14 knots and become gusty.
Have kept TAF dry for now, but will have to watch surface reports
to see if precip aloft now seen on radar begins reaching the
ground this evening. Expect dry air aloft to keep most precip just
to the south of KSTL on Wednesday, but it is a close call.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Crawford MO-
     Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY until 6 PM CST Wednesday FOR Clinton IL-
     Marion IL-Monroe IL-St. Clair IL-Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 040009
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
609 PM CST Tue Mar 3 2015

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 546 PM CST Tue Mar 3 2015

MVFR ceilings will last through much of the night at all TAF
sites as cold front pushes through and stratus deck remains. KUIN
and KCOU will likely be VFR by 10-13Z Wednesday, then VFR ceilings
reach KSTL TAF sites by around 16Z. Will have to watch radar and
surface reports carefully this evening as there is some chance
that precip aloft now seen on regional radars may reach the surface at
KSTL area TAF sites. For now, it appears a dry layer at 6K to 8K
feet may keep this from happening so have left TAFS dry. Northwest
winds behind the front will become gusty and last into Wednesday.

Specifics for KSTL: MVFR ceilings expected until 16Z. Cold front
should reach TAF site by around 06Z, and north winds behind the
cold front will increase to around 14 knots and become gusty.
Have kept TAF dry for now, but will have to watch surface reports
to see if precip aloft now seen on radar begins reaching the
ground this evening. Expect dry air aloft to keep most precip just
to the south of KSTL on Wednesday, but it is a close call.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Crawford MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Clinton IL-Marion IL-Monroe IL-St. Clair IL-
     Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 040009
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
609 PM CST Tue Mar 3 2015

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 546 PM CST Tue Mar 3 2015

MVFR ceilings will last through much of the night at all TAF
sites as cold front pushes through and stratus deck remains. KUIN
and KCOU will likely be VFR by 10-13Z Wednesday, then VFR ceilings
reach KSTL TAF sites by around 16Z. Will have to watch radar and
surface reports carefully this evening as there is some chance
that precip aloft now seen on regional radars may reach the surface at
KSTL area TAF sites. For now, it appears a dry layer at 6K to 8K
feet may keep this from happening so have left TAFS dry. Northwest
winds behind the front will become gusty and last into Wednesday.

Specifics for KSTL: MVFR ceilings expected until 16Z. Cold front
should reach TAF site by around 06Z, and north winds behind the
cold front will increase to around 14 knots and become gusty.
Have kept TAF dry for now, but will have to watch surface reports
to see if precip aloft now seen on radar begins reaching the
ground this evening. Expect dry air aloft to keep most precip just
to the south of KSTL on Wednesday, but it is a close call.

Browning

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Crawford MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Clinton IL-Marion IL-Monroe IL-St. Clair IL-
     Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 032210
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
410 PM CST Tue Mar 3 2015

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Crawford MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Clinton IL-Marion IL-Monroe IL-St. Clair IL-
     Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 032210
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
410 PM CST Tue Mar 3 2015

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Crawford MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Clinton IL-Marion IL-Monroe IL-St. Clair IL-
     Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 032210
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
410 PM CST Tue Mar 3 2015

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Crawford MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Clinton IL-Marion IL-Monroe IL-St. Clair IL-
     Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 032210
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
410 PM CST Tue Mar 3 2015

.SHORT TERM: (Late tonight through Wednesday evening)
Issued at 405 PM CST Tue Mar 3 2015

12z guidance depicts no major changes in expected weather trends
across the area. The next round of cold air is just now entering
the extreme northwest counties of our CWA, and will attempt to
undercut the bands of rain that continue to develop near the KS/OK
border and advected ENE into the mid-Mississippi Valley.

The cold air will become deep enough to begin a transition of the
rain to sleet and perhaps freezing rain as the night progresses,
but as the cold air becomes deep enough to create a mix from
central MO into central IL it appears that the precipitation will
be winding down. However, it should be a different story a bit
further south late tonight and into Wednesday morning, where the
precipitation will be more sustained as the cold air reaches
critical depths. Overall, the general trend overnight across the
southeast half of the CWA should be for the rain to first become
mixed with sleet and freezing rain as the night progresses. The
continued southward progression of the cold air will then change
this icy mix over to all snow near the I-44 corridor early
Wednesday, with the precip in our far southern counties changing
over to all snow no later than midday, and then winding down
Wednesday evening.

The precipitation late tonight and into Wednesday has a lot going
for it. This mornings UA data indicated 10C 850mb dewpoints
already into SW MO, and this moisture will increase into
Wednesday as the SW low level flow just above the cold air
continues the moisture transport. Lift generated by already strong
isentropic ascent will be increasing as baroclinicity strengthens
to our south, with the southwest flow aloft ejecting several
shortwaves into the mid Mississippi Valley enhancing the deep
lift further. Believe the intensity of the lift is showing up in
most of the synoptic models as they all have some indication of
the upper level jet over the upper Great Lakes backbuilding into
our area with time.

QPF and thermal profiles suggest heavy wintry precipitation is
likely from AR into southern MO and southern IL. Snowfall
generated from these parameters indicate 4 to 6 inches of snow/sleet can
be expected over our far southern counties, and because of this
snowfall along with the light glazing produced by the freezing
rain will be going out with a Winter Storm Warning for late
tonight into Wednesday evening for areas along and south of a
Centerville...Sparta line. Just north of the warning area will be
a winter weather advisory from the eastern Ozarks into southern
Illinois, for lesser snowfalls of 2 to 4 inches along with a
possible glaze of ice.

It should be noted that there will be an extremely tight gradient
on the northern edges of the snowfall...roughtly from near
Jefferson City...through St. Louis...to around Vandalia IL. If the
system shifts slightly north the advisory may need to be expanded
into these areas...this evenings and overnight shifts will be
monitoring upstream radar trends to fine tune this tight snowfall gradient.

Ah spring...

Truett

.LONG TERM: (Thursday through Next Tuesday)
Issued at 320 PM CST Tue Mar 3 2015

As upper level long wave trof pushes east, the Arctic air that
enters the region overnight tonight will continue to build and
strengthen over the mid Mississippi Valley. Although the high will
mean few clouds and dry weather, temperatures of this airmass will
be extremely cold for early March. Currently, we are looking for
Thursday morning lows somewhere in the 5 to 12 above range, with
highs only rebounding into the 20s during the afternoon even with
what should be strong sunshine.

Unseasonably cold temperatures will linger on Thursday night, but
return flow should mean the beginnings of a welcomed warmup by Friday.

A split flow regime will initially be in place at the start of the
extended range period featuring a broad longwave trof centered
across eastern NOAM and a quasi rex block along the west coast. The
block will break down by early next week and the overall strength of
the trof weakens, however we largely maintain northwest flow aloft
into Monday. There will be several notable disturbances embedded
within the flow aloft which will traverse the region, bringing a
cold front through the area on Saturday afternoon/night and then
again on Sunday Night. Present indications are that cooling
associated with these fronts will be weak and short-lived. In
general the weekend will be characterized by near average
temperatures and benign/tranquil weather conditions. Next week will
feature a pronounced pattern change, rising heights aloft and above
average temperatures for much of the week.

Truett/Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Crawford MO-Jefferson MO-Washington MO.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Iron MO-Madison MO-Reynolds MO-St.
     Francois MO-Ste. Genevieve MO.

IL...WINTER WEATHER ADVISORY from Midnight tonight to 6 PM CST
     Wednesday FOR Clinton IL-Marion IL-Monroe IL-St. Clair IL-
     Washington IL.

     WINTER STORM WARNING from 3 AM Wednesday to Midnight CST
     Wednesday Night FOR Randolph IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 031740
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1140 AM CST Tue Mar 3 2015

.UPDATE:
Issued at 725 AM CST Tue Mar 3 2015

Surface temperatures have begun to rise in earnest over central
and parts of northeast MO during the past hour as winds have
turned more from the due south. Further east, winds remain from
the SE and any temp rises, if any, have been much less. The
location of the 32F isotherm extends from just south of Kirksville
(IRK) southeastward to the northern STL Metro area and east
towards Vandalia, IL. We anticipate some acceleration in the
warming to expand areawide over the next hour or two as winds
continue to veer more S and eventually SW.

Couple that with pcpn...models have done a good job with
forecasting our brief light rain/freezing rain event at sunrise
and with little in the way of echo to the west behind it, lots of
very low clouds in its wake filling in behind it, and some weak
low level convergence from warm front slowly lifting north, should
see patchy drizzle for pcpn from time to time thru about early
afternoon.

Putting it all together, currently anticipate being able to allow
the Advisory to expire everywhere at 8am this morning with limited
areas still below freezing at that time and only very light pcpn
if any left.

TES
&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS
&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

&&

$$
WFO LSX






000
FXUS63 KLSX 031740
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1140 AM CST Tue Mar 3 2015

.UPDATE:
Issued at 725 AM CST Tue Mar 3 2015

Surface temperatures have begun to rise in earnest over central
and parts of northeast MO during the past hour as winds have
turned more from the due south. Further east, winds remain from
the SE and any temp rises, if any, have been much less. The
location of the 32F isotherm extends from just south of Kirksville
(IRK) southeastward to the northern STL Metro area and east
towards Vandalia, IL. We anticipate some acceleration in the
warming to expand areawide over the next hour or two as winds
continue to veer more S and eventually SW.

Couple that with pcpn...models have done a good job with
forecasting our brief light rain/freezing rain event at sunrise
and with little in the way of echo to the west behind it, lots of
very low clouds in its wake filling in behind it, and some weak
low level convergence from warm front slowly lifting north, should
see patchy drizzle for pcpn from time to time thru about early
afternoon.

Putting it all together, currently anticipate being able to allow
the Advisory to expire everywhere at 8am this morning with limited
areas still below freezing at that time and only very light pcpn
if any left.

TES
&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS
&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

&&

$$
WFO LSX






000
FXUS63 KLSX 031740
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1140 AM CST Tue Mar 3 2015

.UPDATE:
Issued at 725 AM CST Tue Mar 3 2015

Surface temperatures have begun to rise in earnest over central
and parts of northeast MO during the past hour as winds have
turned more from the due south. Further east, winds remain from
the SE and any temp rises, if any, have been much less. The
location of the 32F isotherm extends from just south of Kirksville
(IRK) southeastward to the northern STL Metro area and east
towards Vandalia, IL. We anticipate some acceleration in the
warming to expand areawide over the next hour or two as winds
continue to veer more S and eventually SW.

Couple that with pcpn...models have done a good job with
forecasting our brief light rain/freezing rain event at sunrise
and with little in the way of echo to the west behind it, lots of
very low clouds in its wake filling in behind it, and some weak
low level convergence from warm front slowly lifting north, should
see patchy drizzle for pcpn from time to time thru about early
afternoon.

Putting it all together, currently anticipate being able to allow
the Advisory to expire everywhere at 8am this morning with limited
areas still below freezing at that time and only very light pcpn
if any left.

TES
&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS
&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1130 AM CST Tue Mar 3 2015

IFR/low end MVFR to persist across forecast area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage between 21z Tuesday and 00z
Wednesday, then to veer to the north after 03z-05z Wednesday.
Through forecast period, best chances of precipitation will be
just south of taf sites, so kept mention out for now. Cigs to lift
to VFR between 10z-16z Wednesday.

Specifics for KSTL:
IFR/low end MVFR to persist across metro area ahead of cold
front with winds picking up from the southwest. Winds to veer to
the west with frontal passage after 00z Wednesday, then to veer
to the north after 05z Wednesday. Through forecast period, best
chances of precipitation will be just south of metro area, so kept
mention out for now. Cigs to lift to VFR by 16z Wednesday.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

&&

$$
WFO LSX







000
FXUS63 KLSX 031325
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
725 AM CST Tue Mar 3 2015

.UPDATE:
Issued at 725 AM CST Tue Mar 3 2015

Surface temperatures have begun to rise in earnest over central
and parts of northeast MO during the past hour as winds have
turned more from the due south. Further east, winds remain from
the SE and any temp rises, if any, have been much less. The
location of the 32F isotherm extends from just south of Kirksville
(IRK) southeastward to the northern STL Metro area and east
towards Vandalia, IL. We anticipate some acceleration in the
warming to expand areawide over the next hour or two as winds
continue to veer more S and eventually SW.

Couple that with pcpn...models have done a good job with
forecasting our brief light rain/freezing rain event at sunrise
and with little in the way of echo to the west behind it, lots of
very low clouds in its wake filling in behind it, and some weak
low level convergence from warm front slowly lifting north, should
see patchy drizzle for pcpn from time to time thru about early
afternoon.

Putting it all together, currently anticipate being able to allow
the Advisory to expire everywhere at 8am this morning with limited
areas still below freezing at that time and only very light pcpn
if any left.

TES

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 533 AM CST Tue Mar 3 2015

Light rain still expected to develop into the STL metro area early
this morning and should be to the east of the area by 15z. By the
time it does develop, temps should be above freezing, however, and
have went with plain rain for a pcpn-type. UIN the exception and
have gone with FZDZ thru 14z before ending. MVFR CIGs currently
the rule at the TAF sites, but IFR CIGs closing in on all sides
and anticipate them to prevail in the next hour or two. Low CIGs
to then prevail thru the day and into early this evening with some
improvement back to MVFR CIGs expected from the anticipated
morning IFR. A cold front then moves thru late this afternoon and
early this evening, and with the drier air, result in improving
categories to VFR during the night. A quick shot of rain expected
behind the front for areas S and E of STL, and have thus added to
the CPS TAF and may need to be expanded to the other STL metro
sites.

Specifics for KSTL: Light rain to develop imminently and continue
until 14/15z, with IFR CIGs developing on the backside. IFR to
then continue into midday before some improvement. A cold front
then moves thru early this evening, and with the drier air,
result in improving categories to VFR during the night. A quick
shot of rain expected behind the front for areas S and E of STL,
and may need to be expanded to this terminal.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 031325
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
725 AM CST Tue Mar 3 2015

.UPDATE:
Issued at 725 AM CST Tue Mar 3 2015

Surface temperatures have begun to rise in earnest over central
and parts of northeast MO during the past hour as winds have
turned more from the due south. Further east, winds remain from
the SE and any temp rises, if any, have been much less. The
location of the 32F isotherm extends from just south of Kirksville
(IRK) southeastward to the northern STL Metro area and east
towards Vandalia, IL. We anticipate some acceleration in the
warming to expand areawide over the next hour or two as winds
continue to veer more S and eventually SW.

Couple that with pcpn...models have done a good job with
forecasting our brief light rain/freezing rain event at sunrise
and with little in the way of echo to the west behind it, lots of
very low clouds in its wake filling in behind it, and some weak
low level convergence from warm front slowly lifting north, should
see patchy drizzle for pcpn from time to time thru about early
afternoon.

Putting it all together, currently anticipate being able to allow
the Advisory to expire everywhere at 8am this morning with limited
areas still below freezing at that time and only very light pcpn
if any left.

TES

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 533 AM CST Tue Mar 3 2015

Light rain still expected to develop into the STL metro area early
this morning and should be to the east of the area by 15z. By the
time it does develop, temps should be above freezing, however, and
have went with plain rain for a pcpn-type. UIN the exception and
have gone with FZDZ thru 14z before ending. MVFR CIGs currently
the rule at the TAF sites, but IFR CIGs closing in on all sides
and anticipate them to prevail in the next hour or two. Low CIGs
to then prevail thru the day and into early this evening with some
improvement back to MVFR CIGs expected from the anticipated
morning IFR. A cold front then moves thru late this afternoon and
early this evening, and with the drier air, result in improving
categories to VFR during the night. A quick shot of rain expected
behind the front for areas S and E of STL, and have thus added to
the CPS TAF and may need to be expanded to the other STL metro
sites.

Specifics for KSTL: Light rain to develop imminently and continue
until 14/15z, with IFR CIGs developing on the backside. IFR to
then continue into midday before some improvement. A cold front
then moves thru early this evening, and with the drier air,
result in improving categories to VFR during the night. A quick
shot of rain expected behind the front for areas S and E of STL,
and may need to be expanded to this terminal.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 031133
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
533 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 533 AM CST Tue Mar 3 2015

Light rain still expected to develop into the STL metro area early
this morning and should be to the east of the area by 15z. By the
time it does develop, temps should be above freezing, however, and
have went with plain rain for a pcpn-type. UIN the exception and
have gone with FZDZ thru 14z before ending. MVFR CIGs currently
the rule at the TAF sites, but IFR CIGs closing in on all sides
and anticipate them to prevail in the next hour or two. Low CIGs
to then prevail thru the day and into early this evening with some
improvement back to MVFR CIGs expected from the anticipated
morning IFR. A cold front then moves thru late this afternoon and
early this evening, and with the drier air, result in improving
categories to VFR during the night. A quick shot of rain expected
behind the front for areas S and E of STL, and have thus added to
the CPS TAF and may need to be expanded to the other STL metro
sites.

Specifics for KSTL: Light rain to develop imminently and continue
until 14/15z, with IFR CIGs developing on the backside. IFR to
then continue into midday before some improvement. A cold front
then moves thru early this evening, and with the drier air,
result in improving categories to VFR during the night. A quick
shot of rain expected behind the front for areas S and E of STL,
and may need to be expanded to this terminal.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX





000
FXUS63 KLSX 031133
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
533 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 533 AM CST Tue Mar 3 2015

Light rain still expected to develop into the STL metro area early
this morning and should be to the east of the area by 15z. By the
time it does develop, temps should be above freezing, however, and
have went with plain rain for a pcpn-type. UIN the exception and
have gone with FZDZ thru 14z before ending. MVFR CIGs currently
the rule at the TAF sites, but IFR CIGs closing in on all sides
and anticipate them to prevail in the next hour or two. Low CIGs
to then prevail thru the day and into early this evening with some
improvement back to MVFR CIGs expected from the anticipated
morning IFR. A cold front then moves thru late this afternoon and
early this evening, and with the drier air, result in improving
categories to VFR during the night. A quick shot of rain expected
behind the front for areas S and E of STL, and have thus added to
the CPS TAF and may need to be expanded to the other STL metro
sites.

Specifics for KSTL: Light rain to develop imminently and continue
until 14/15z, with IFR CIGs developing on the backside. IFR to
then continue into midday before some improvement. A cold front
then moves thru early this evening, and with the drier air,
result in improving categories to VFR during the night. A quick
shot of rain expected behind the front for areas S and E of STL,
and may need to be expanded to this terminal.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX






000
FXUS63 KLSX 031133
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
533 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 533 AM CST Tue Mar 3 2015

Light rain still expected to develop into the STL metro area early
this morning and should be to the east of the area by 15z. By the
time it does develop, temps should be above freezing, however, and
have went with plain rain for a pcpn-type. UIN the exception and
have gone with FZDZ thru 14z before ending. MVFR CIGs currently
the rule at the TAF sites, but IFR CIGs closing in on all sides
and anticipate them to prevail in the next hour or two. Low CIGs
to then prevail thru the day and into early this evening with some
improvement back to MVFR CIGs expected from the anticipated
morning IFR. A cold front then moves thru late this afternoon and
early this evening, and with the drier air, result in improving
categories to VFR during the night. A quick shot of rain expected
behind the front for areas S and E of STL, and have thus added to
the CPS TAF and may need to be expanded to the other STL metro
sites.

Specifics for KSTL: Light rain to develop imminently and continue
until 14/15z, with IFR CIGs developing on the backside. IFR to
then continue into midday before some improvement. A cold front
then moves thru early this evening, and with the drier air,
result in improving categories to VFR during the night. A quick
shot of rain expected behind the front for areas S and E of STL,
and may need to be expanded to this terminal.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX





000
FXUS63 KLSX 031133
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
533 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 533 AM CST Tue Mar 3 2015

Light rain still expected to develop into the STL metro area early
this morning and should be to the east of the area by 15z. By the
time it does develop, temps should be above freezing, however, and
have went with plain rain for a pcpn-type. UIN the exception and
have gone with FZDZ thru 14z before ending. MVFR CIGs currently
the rule at the TAF sites, but IFR CIGs closing in on all sides
and anticipate them to prevail in the next hour or two. Low CIGs
to then prevail thru the day and into early this evening with some
improvement back to MVFR CIGs expected from the anticipated
morning IFR. A cold front then moves thru late this afternoon and
early this evening, and with the drier air, result in improving
categories to VFR during the night. A quick shot of rain expected
behind the front for areas S and E of STL, and have thus added to
the CPS TAF and may need to be expanded to the other STL metro
sites.

Specifics for KSTL: Light rain to develop imminently and continue
until 14/15z, with IFR CIGs developing on the backside. IFR to
then continue into midday before some improvement. A cold front
then moves thru early this evening, and with the drier air,
result in improving categories to VFR during the night. A quick
shot of rain expected behind the front for areas S and E of STL,
and may need to be expanded to this terminal.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX






000
FXUS63 KLSX 031004
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
404 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1149 PM CST Mon Mar 2 2015

Specifics for KCOU, KUIN: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front. As
temperatures rise late overnight and towards morning, the freezing
rain will transition over to rain. The onset of MVFR and IFR
ceilings has been a bit slower than previously anticipated.
Initially southeasterly to southerly winds will become
southwesterly during the day, then turn sharply northwesterly
after a cold front moves through the area towards the end of the
valid TAF period.

Specifics for KSTL, KSUS, KCPS: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front at
TAF issuance. As temperatures rise late overnight and towards
morning, the freezing rain will transition over to rain. Although
the onset of MVFR and IFR cigs has been a bit slower than
previously anticipated, upstream METARs do show lower cigs
occurring with and behind the precip. Initially southeasterly to
southerly winds will become southwesterly during the day, then
turn sharply northwesterly after a cold front moves through the
area on Tuesday night.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 031004
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
404 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1149 PM CST Mon Mar 2 2015

Specifics for KCOU, KUIN: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front. As
temperatures rise late overnight and towards morning, the freezing
rain will transition over to rain. The onset of MVFR and IFR
ceilings has been a bit slower than previously anticipated.
Initially southeasterly to southerly winds will become
southwesterly during the day, then turn sharply northwesterly
after a cold front moves through the area towards the end of the
valid TAF period.

Specifics for KSTL, KSUS, KCPS: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front at
TAF issuance. As temperatures rise late overnight and towards
morning, the freezing rain will transition over to rain. Although
the onset of MVFR and IFR cigs has been a bit slower than
previously anticipated, upstream METARs do show lower cigs
occurring with and behind the precip. Initially southeasterly to
southerly winds will become southwesterly during the day, then
turn sharply northwesterly after a cold front moves through the
area on Tuesday night.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX








000
FXUS63 KLSX 031004
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
404 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1149 PM CST Mon Mar 2 2015

Specifics for KCOU, KUIN: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front. As
temperatures rise late overnight and towards morning, the freezing
rain will transition over to rain. The onset of MVFR and IFR
ceilings has been a bit slower than previously anticipated.
Initially southeasterly to southerly winds will become
southwesterly during the day, then turn sharply northwesterly
after a cold front moves through the area towards the end of the
valid TAF period.

Specifics for KSTL, KSUS, KCPS: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front at
TAF issuance. As temperatures rise late overnight and towards
morning, the freezing rain will transition over to rain. Although
the onset of MVFR and IFR cigs has been a bit slower than
previously anticipated, upstream METARs do show lower cigs
occurring with and behind the precip. Initially southeasterly to
southerly winds will become southwesterly during the day, then
turn sharply northwesterly after a cold front moves through the
area on Tuesday night.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

WFO LSX







000
FXUS63 KLSX 031004
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
404 AM CST Tue Mar 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 403 AM CST Tue Mar 3 2015

At 09z, the critical 32F isotherm was draped near I-70 in MO and
then curved southeastward near the MS river with much of IL at or
below freezing.  There remains a decent dewpoint depression of
around 10 degrees in place for many locations, giving some room to
spare when pcpn does get going, to prevent too great of a temp rise
too soon.  SE surface winds are already in place, though, resulting
in some weak WAA.

The models are in decent agreement on a batch of light pcpn
developing over central MO in the next couple hours and then
propagating eastward down I-70 into STL metro and into southwestern
IL, developing and growing as it does so.  Given the decent dewpoint
depressions, the pcpn development should act to counter or severely
retard any temp rises for the next several hours until it passes
thru by mid-late morning.  This could be a key point, with the 32F
isotherm not really expected to budge much thru about 12-13z/06-07am
and should result in light FZRA/FZDZ for many areas near and north
of I-70 with the potential for a light glazing still in place.
While ice accums look to be pretty spotty for areas outside of
northeast MO and west-central IL, will maintain current alignment of
the Winter Wx Advisory since brief FZRA periods are still expected
throughout these areas.

Once we get past mid-late morning, the midday and afternoon hours
look pretty quiet from a sensible wx perspective with spotty drizzle
perhaps the only pcpn expected.  Pcpn for the event heading into
tonight will try to get going very late this afternoon but should
largely hold off until after sundown.

Cloudy skies will limit the warmup we could have, but gusty S-SW
winds will do their part, with temp readings ranging from the 40s
north of I-70, to the lower 50s for many areas south.

TES

.LONG TERM:  (Tonight through Monday)
Issued at 403 AM CST Tue Mar 3 2015

Cold front will drop southeast of our forecast area this evening.
Rain will continue this evening across southeast MO and southwest
IL, mainly southeast of STL due to low-mid level warm air advection
ahead of weak southwest flow shortwaves along with mid level
frontogenesis behind the surface front.  As the initially shallow
cold layer progresses southeastward the rain will change to freezing
rain, then briefly to sleet and finally to snow late tonight.  There
will likely be some minor ice and snow/sleet accumulations late
tonight southeast of STL.  Precipitation should ramp up on Wednesday
as a positively tilted upper level trough approaches with increasing
upper level divergence across our area in the right entrance region
of an upper level jet streak over the Great Lakes region.  The
strongest low-mid level warm air advection along with the best low
level moisture should continue to be across southeast MO and
southwest IL.  The NAM model appears a little too strong with this
low level forcing and also stronger with a southern stream shortwave
and hence has more qpf as well as its precipitation extending a
little further north than the other models.  Went closer to the
ECMWF model solution for Wednesday and Wednesday night as its a
compromise between the NAM and the GFS which has the precipitation
shield further south and is also lighter on the amounts.  There will
continue to be sleet and freezing rain Wednesday morning across
southeast MO and southwest IL, but as the cold layer deepens and the
elevated warm layer shrinks the precipitation should change over to
all snow by Wednesday afternoon.  The snow will taper off by late
Wednesday night and shift southeast of our forecast area.  With
still plenty of model uncertainty with regards to precipitation
amounts and how far north the significant snow will extend will just
issue a winter storm watch for Wednesday and Wednesday evening for a
small portion of southeast MO and southwest IL where there will be
at least a light glazing of ice Wednesday morning followed by the
potential of a total snow accumulation of around 4 to 7 inches.
Little diurnal temperature rise is expected on Wednesday with cold
air advection along with cloud cover and precipitation.  Wednesday
night and Thursday will be unseasonably cold as the strong surface
high moves southeastward through the region with the models dropping
the -16 degree C 850 mb isotherm southward to just south of STL by
Thursday morning.  Warmer temperatures are expected by Friday as the
surface wind comes around to a southerly direction as the surface
ridge shifts east of our area.  A weak cold front will move
southeastward through the forecast area on Saturday and Saturday
evening, but it appears that any precipitation will remain northeast
of our forecast area ahead of a northern stream shortwave and in the
vicinity of an associated surface low.  Only slight cooling is
expected for the remainder of the weekend after passage of the cold
front, mainly across northeast MO and west central IL. Temperatures
for the weekend into early next week should be close to seasonal
normals for early March.

GKS

&&

.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1149 PM CST Mon Mar 2 2015

Specifics for KCOU, KUIN: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front. As
temperatures rise late overnight and towards morning, the freezing
rain will transition over to rain. The onset of MVFR and IFR
ceilings has been a bit slower than previously anticipated.
Initially southeasterly to southerly winds will become
southwesterly during the day, then turn sharply northwesterly
after a cold front moves through the area towards the end of the
valid TAF period.

Specifics for KSTL, KSUS, KCPS: Light freezing rain was spreading
northeastward across the region ahead of a lifting warm front at
TAF issuance. As temperatures rise late overnight and towards
morning, the freezing rain will transition over to rain. Although
the onset of MVFR and IFR cigs has been a bit slower than
previously anticipated, upstream METARs do show lower cigs
occurring with and behind the precip. Initially southeasterly to
southerly winds will become southwesterly during the day, then
turn sharply northwesterly after a cold front moves through the
area on Tuesday night.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Iron MO-Madison MO-Reynolds MO-St. Francois MO-
     Ste. Genevieve MO.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Audrain
     MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Monroe MO-
     Montgomery MO-Pike MO-Ralls MO-Shelby MO-St. Charles MO-St.
     Louis City MO-St. Louis MO-Warren MO.

IL...WINTER STORM WATCH from Wednesday morning through Wednesday
     evening FOR Randolph IL.

     WINTER WEATHER ADVISORY until 8 AM CST this morning FOR Adams IL-
     Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-
     Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL-
     Pike IL-St. Clair IL.

&&

$$

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