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000
FXUS65 KTFX 230456
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 PM MDT Mon Sep 22 2014

Aviation section updated

.UPDATE...
Current forecast is on track. Just confined pops for tonight to
Southwest Montana...mainly Beaverhead County...where light rain
showers continue. Temperatures are on track...with just a few
minor tweaks.

Looking ahead...another round of showers/thunderstorms will affect
mainly the western half of the region on Tuesday...then a very
warm day is expected on Wednesday...with a few locations nearing
record highs. The next Pacific cold front should arrive
Fri/Sat...depending on the timing differences per GFS/EC models.
Brusda

&&

.AVIATION...
UPDATED 0500Z.
VFR conditions will prevail at all terminals through 21z Tuesday.
Then another round of showers/thunderstorms will affect the
region...mainly Rocky Mountain Front and in Southwest MT. MVFR
conditions will be possible in/near thunderstorms. Expect mainly VFR
conditions after 03z Wednesday. Brusda

&&

.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Sep 22 2014/

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /   0  10  10   0
BZN  46  79  49  84 /  10  10  10   0
WEY  37  67  37  74 /  20  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /   0  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 230456
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 PM MDT Mon Sep 22 2014

Aviation section updated

.UPDATE...
Current forecast is on track. Just confined pops for tonight to
Southwest Montana...mainly Beaverhead County...where light rain
showers continue. Temperatures are on track...with just a few
minor tweaks.

Looking ahead...another round of showers/thunderstorms will affect
mainly the western half of the region on Tuesday...then a very
warm day is expected on Wednesday...with a few locations nearing
record highs. The next Pacific cold front should arrive
Fri/Sat...depending on the timing differences per GFS/EC models.
Brusda

&&

.AVIATION...
UPDATED 0500Z.
VFR conditions will prevail at all terminals through 21z Tuesday.
Then another round of showers/thunderstorms will affect the
region...mainly Rocky Mountain Front and in Southwest MT. MVFR
conditions will be possible in/near thunderstorms. Expect mainly VFR
conditions after 03z Wednesday. Brusda

&&

.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Sep 22 2014/

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /   0  10  10   0
BZN  46  79  49  84 /  10  10  10   0
WEY  37  67  37  74 /  20  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /   0  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 230218
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
818 PM MDT Mon Sep 22 2014

.UPDATE...
Current forecast is on track. Just confined pops for tonight to
Southwest Montana...mainly Beaverhead County...where light rain
showers continue. Temperatures are on track...with just a few
minor tweaks.

Looking ahead...another round of showers/thunderstorms will affect
mainly the western half of the region on Tuesday...then a very
warm day is expected on Wednesday...with a few locations nearing
record highs. The next Pacific cold front should arrive
Fri/Sat...depending on the timing differences per GFS/EC models.
Brusda

&&

.AVIATION...
UPDATED 2330Z.
Scattered showers and isolated thunderstorms will affect Southwest
MT through 06z Tue. Expect mountains to be obscured in the
Southwest...with MVFR conditions in/near thunderstorms. Otherwise
VFR conditions will prevail at all terminals through the period.
There will be another round of showers/thunderstorms after 21z
Tuesday and these storms will affect areas along the Rocky Mountain
Front and near Helena. Brusda

&&

.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Sep 22 2014/

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /   0  10  10   0
BZN  46  79  49  84 /  20  10  10   0
WEY  37  67  37  74 /  30  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /   0  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 230218
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
818 PM MDT Mon Sep 22 2014

.UPDATE...
Current forecast is on track. Just confined pops for tonight to
Southwest Montana...mainly Beaverhead County...where light rain
showers continue. Temperatures are on track...with just a few
minor tweaks.

Looking ahead...another round of showers/thunderstorms will affect
mainly the western half of the region on Tuesday...then a very
warm day is expected on Wednesday...with a few locations nearing
record highs. The next Pacific cold front should arrive
Fri/Sat...depending on the timing differences per GFS/EC models.
Brusda

&&

.AVIATION...
UPDATED 2330Z.
Scattered showers and isolated thunderstorms will affect Southwest
MT through 06z Tue. Expect mountains to be obscured in the
Southwest...with MVFR conditions in/near thunderstorms. Otherwise
VFR conditions will prevail at all terminals through the period.
There will be another round of showers/thunderstorms after 21z
Tuesday and these storms will affect areas along the Rocky Mountain
Front and near Helena. Brusda

&&

.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Sep 22 2014/

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /   0  10  10   0
BZN  46  79  49  84 /  20  10  10   0
WEY  37  67  37  74 /  30  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /   0  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 222330
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
530 PM MDT Mon Sep 22 2014

Aviation section updated

.DISCUSSION...

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.AVIATION...
UPDATED 2330Z.
Scattered showers and isolated thunderstorms will affect Southwest
MT through 06z Tue. Expect mountains to be obscured in the
Southwest...with MVFR conditions in/near thunderstorms. Otherwise
VFR conditions will prevail at all terminals through the period.
There will be another round of showers/thunderstorms after 21z
Tuesday and these storms will affect areas along the Rocky Mountain
Front and near Helena. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /  10  10  10   0
BZN  46  79  49  84 /  20  10  10   0
WEY  35  67  37  74 /  30  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 222330
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
530 PM MDT Mon Sep 22 2014

Aviation section updated

.DISCUSSION...

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.AVIATION...
UPDATED 2330Z.
Scattered showers and isolated thunderstorms will affect Southwest
MT through 06z Tue. Expect mountains to be obscured in the
Southwest...with MVFR conditions in/near thunderstorms. Otherwise
VFR conditions will prevail at all terminals through the period.
There will be another round of showers/thunderstorms after 21z
Tuesday and these storms will affect areas along the Rocky Mountain
Front and near Helena. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /  10  10  10   0
BZN  46  79  49  84 /  20  10  10   0
WEY  35  67  37  74 /  30  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls





000
FXUS65 KTFX 222044
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
244 PM MDT Mon Sep 22 2014

.DISCUSSION...

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.AVIATION...
UPDATED 1800Z.
VFR conditions will prevail through the period. Moisture wrapping
around a disturbance over SW Montana/NW Wyoming will bring mid level
cloudiness as far north as KGTF-KLWT. Scattered showers and isolated
afternoon/evening thunderstorms will be limited to Southwest Montana
(including KBZN). Some storms may produce brief heavy rain and MVFR
conditions. Activity decreases after 02Z. West winds will be light
but may become breezy at times along the east slopes of the Rockies.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /  10  10  10   0
BZN  46  79  49  84 /  20  10  10   0
WEY  35  67  37  74 /  30  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 222044
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
244 PM MDT Mon Sep 22 2014

.DISCUSSION...

Tonight through Wednesday...Central Montana is underneath a high
pressure ridge although a weak, cut-off low is moving through
Southwest Montana. Weak instability has developed but the air mass
will stabilize quickly this evening. An upper level jet will
approach the Northern Rockies Tuesday afternoon and surface winds
will hookup during the afternoon for some breezy surface winds. This
jet could also support convection during the afternoon and evening
over the Rockies although these should be north of the border. The
jet moves north and heights aloft will build Wednesday. The air mass
will warm and max temps will continue well above normals. Zelzer

Wednesday Night through Monday...High pressure begins to move east
of the area Thursday as a trough off the Pacific Northwest coast
begins to move onshore. The area will remain dry and warm.

Model differences occur towards the end of the week as the trough
moves onshore. The GFS is about 24 hours faster than the ECMWF with
the progression. Both models develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. The ECMWF weakens it and moves it slower, lingering into
Monday. The GFS moves it east over the Central Rockies and out of
the area by Monday. As a result, models generally bring a chance of
showers/thunderstorms into the area Thursday night into Friday,
continuing through Sunday. Exact areas of potentially heavier
rainfall are not well agreed upon, so kept a broad high chance for
showers/storms through the period. With this discrepancy later
in the forecast period, kept the chance for showers higher than
climatological normal and will adjust as necessary as models
hopefully come into better agreement. A much cooler airmass moves
into the area with the trough, cooling from mostly 70s on Friday
into the mid 50s to mid 60s on Saturday. This may result in some
mountains receiving a rain/snow mix during the overnight hours.

&&

.AVIATION...
UPDATED 1800Z.
VFR conditions will prevail through the period. Moisture wrapping
around a disturbance over SW Montana/NW Wyoming will bring mid level
cloudiness as far north as KGTF-KLWT. Scattered showers and isolated
afternoon/evening thunderstorms will be limited to Southwest Montana
(including KBZN). Some storms may produce brief heavy rain and MVFR
conditions. Activity decreases after 02Z. West winds will be light
but may become breezy at times along the east slopes of the Rockies.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  83  57  88 /   0  10   0   0
CTB  46  81  47  86 /   0  10  10   0
HLN  51  83  53  88 /  10  10  10   0
BZN  46  79  49  84 /  20  10  10   0
WEY  35  67  37  74 /  30  10   0   0
DLN  48  77  51  83 /  20  10  10   0
HVR  50  86  52  91 /   0   0   0   0
LWT  51  83  54  89 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 221805
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1200 PM MDT Mon Sep 22 2014

.UPDATE...

Today...Update to zones not planned...Very weak instability will
develop over Southwest Montana today. Some fairly high precipitable
water for this time of the year so some local heavy rain is
possible underneath slow moving storms. Current forecast on
track. Zelzer

&&


.AVIATION...
UPDATED 1800Z.
VFR conditions will prevail through the period. Moisture wrapping
around a disturbance over SW Montana/NW Wyoming will bring mid level
cloudiness as far north as KGTF-KLWT. Scattered showers and isolated
afternoon/evening thunderstorms will be limited to Southwest Montana
(including KBZN). Some storms may produce brief heavy rain and MVFR
conditions. Activity decreases after 02Z. West winds will be light
but may become breezy at times along the east slopes of the Rockies.

&&

.PREV DISCUSSION...
/ISSUED 535 AM MDT Mon Sep 22 2014/

As of ~1000Z, cut-off mid-level low, within a much larger scale
upper-level ridge, was located along the Utah/Idaho border and was
slowly moving ENE as seen on WV imagery loop. Enough elevated
instability associated with the low for lightning strikes as far
north as northern Utah. Cyclonic flow around this low in the mid
levels will continue to advect higher mixing ratios into SW MT
into this aftn. Initial band of rain showers have developed in
area of PVA with -RA reported at W. Yellowstone and Dillon.

Today and Tonight...the level of tropospheric moisture in this
system is quite impressive, most of which likely originated from the
E Pacific off the coasts of S California and NW Mexico. Over SW MT,
precipitable water is forecast to be near 1 inch with 0.50 - 0.75
inch values expected over north-central MT. The 1 inch PWAT values
across SW MT are very anomalous for the end of Sept., and are 3-4
standard deviations above the mean or greater than the 99.5
percentile.

The high amount of moisture and weak mid-level steering flow
would point at the possibility for slow moving showers/storms and
the potential for localized flooding. However, the good news is
that weak/disorganized upper-level forcing for ascent will
inhibit widespread precip with this event. Nonetheless, isolated
areas in Southern Beaverhead, Madison, and Gallatin Counties may
experience hourly rainfall rates approaching or exceeding 0.50
inches/per hour during the morning and aftn hours. As usual,
valleys near mountainous terrain would be most prone to flash
flooding. Hi-Res NMM redevelops isolated to sct slow moving
showers and storms this aftn and evening with a focus over the SW
mountains.

Tuesday and Wednesday...Well above average temps will continue
along with mainly dry conditions as upper low pulls away. Even as
a large-scale trough approaches the Pacific NW, heights will
continue to rise to near 588 dam...1000-500mb thicknesses near 580
dam by Wednesday aftn. Highs over the lower elevations will range
from near 80F over the SW to the upper 80s close to 90F over
north-central/northeast portion of the forecast area. Uttech

Wednesday Night through Monday...High pressure aloft will begin to
move slowly east of the area on Thursday as a deep upper level
trough off the Pacific Northwest coast begins to move onshore.
The area will remain dry with temperatures similar to those
from Wednesday (15 to 20 degrees above normal).

Model differences occur as the trough moves onshore and toward
Montana. The GFS is about 24 hours faster than the ECMWF with the
progression of the trough. They both develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. However, the ECMWF weakens it into an open wave trough that
continues to move slower than the other models and lingers over
Montana into Monday. The GFS keeps the feature as a cut-off low and
moves it east over the central Rockies and out of the area Sunday
night into Monday. As a result, the models agree to initially bring
a chance of showers/thunderstorms into the area Thursday night into
Friday and continue it through Sunday. However, the placement of the
potentially heavier rainfall is not agreed upon, so have decided to
go with a broad-brushed high chance for showers/storms across the
area through the period. Again, as mentioned above, the GFS then
decreases the chance of precipitation significantly after Sunday,
while the ECMWF holds on to a good chance of showers into Monday.
Again, with this kind of discrepancy this late in the forecast
period, I have decided to keep the chance for showers higher than
climatological normals and adjust as necessary as the models
hopefully come into better agreement.

The other concern with this system will be temperatures. Forecast
model compromise brings a much cooler airmass into the area with the
cut-off low/upper trough. As the system brings increasing
clouds/showers and a cold front into the area Friday into Saturday,
temperatures will cool from mostly 70s on Friday (about 10 degrees
above normal) into the mid 50s to mid 60s on Saturday (about 5 to 10
degrees below normal). With the faster exit of the system by the
GFS, it begins warming temperatures on Monday. However, have
maintained the trend of a lingering system and kept temperatures
similarly cool through the end of the period. This may cause some
mountains to get a rain/snow mix during the overnight hours.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  53  83  55 /  10   0  10  10
CTB  83  46  81  48 /   0   0  20  10
HLN  82  51  83  53 /  20  10  20  10
BZN  76  47  79  48 /  20  10  10  10
WEY  62  36  68  37 /  60  30  10   0
DLN  73  48  78  50 /  50  20  10  10
HVR  83  50  86  52 /   0   0   0  10
LWT  81  51  84  53 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 221805
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1200 PM MDT Mon Sep 22 2014

.UPDATE...

Today...Update to zones not planned...Very weak instability will
develop over Southwest Montana today. Some fairly high precipitable
water for this time of the year so some local heavy rain is
possible underneath slow moving storms. Current forecast on
track. Zelzer

&&


.AVIATION...
UPDATED 1800Z.
VFR conditions will prevail through the period. Moisture wrapping
around a disturbance over SW Montana/NW Wyoming will bring mid level
cloudiness as far north as KGTF-KLWT. Scattered showers and isolated
afternoon/evening thunderstorms will be limited to Southwest Montana
(including KBZN). Some storms may produce brief heavy rain and MVFR
conditions. Activity decreases after 02Z. West winds will be light
but may become breezy at times along the east slopes of the Rockies.

&&

.PREV DISCUSSION...
/ISSUED 535 AM MDT Mon Sep 22 2014/

As of ~1000Z, cut-off mid-level low, within a much larger scale
upper-level ridge, was located along the Utah/Idaho border and was
slowly moving ENE as seen on WV imagery loop. Enough elevated
instability associated with the low for lightning strikes as far
north as northern Utah. Cyclonic flow around this low in the mid
levels will continue to advect higher mixing ratios into SW MT
into this aftn. Initial band of rain showers have developed in
area of PVA with -RA reported at W. Yellowstone and Dillon.

Today and Tonight...the level of tropospheric moisture in this
system is quite impressive, most of which likely originated from the
E Pacific off the coasts of S California and NW Mexico. Over SW MT,
precipitable water is forecast to be near 1 inch with 0.50 - 0.75
inch values expected over north-central MT. The 1 inch PWAT values
across SW MT are very anomalous for the end of Sept., and are 3-4
standard deviations above the mean or greater than the 99.5
percentile.

The high amount of moisture and weak mid-level steering flow
would point at the possibility for slow moving showers/storms and
the potential for localized flooding. However, the good news is
that weak/disorganized upper-level forcing for ascent will
inhibit widespread precip with this event. Nonetheless, isolated
areas in Southern Beaverhead, Madison, and Gallatin Counties may
experience hourly rainfall rates approaching or exceeding 0.50
inches/per hour during the morning and aftn hours. As usual,
valleys near mountainous terrain would be most prone to flash
flooding. Hi-Res NMM redevelops isolated to sct slow moving
showers and storms this aftn and evening with a focus over the SW
mountains.

Tuesday and Wednesday...Well above average temps will continue
along with mainly dry conditions as upper low pulls away. Even as
a large-scale trough approaches the Pacific NW, heights will
continue to rise to near 588 dam...1000-500mb thicknesses near 580
dam by Wednesday aftn. Highs over the lower elevations will range
from near 80F over the SW to the upper 80s close to 90F over
north-central/northeast portion of the forecast area. Uttech

Wednesday Night through Monday...High pressure aloft will begin to
move slowly east of the area on Thursday as a deep upper level
trough off the Pacific Northwest coast begins to move onshore.
The area will remain dry with temperatures similar to those
from Wednesday (15 to 20 degrees above normal).

Model differences occur as the trough moves onshore and toward
Montana. The GFS is about 24 hours faster than the ECMWF with the
progression of the trough. They both develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. However, the ECMWF weakens it into an open wave trough that
continues to move slower than the other models and lingers over
Montana into Monday. The GFS keeps the feature as a cut-off low and
moves it east over the central Rockies and out of the area Sunday
night into Monday. As a result, the models agree to initially bring
a chance of showers/thunderstorms into the area Thursday night into
Friday and continue it through Sunday. However, the placement of the
potentially heavier rainfall is not agreed upon, so have decided to
go with a broad-brushed high chance for showers/storms across the
area through the period. Again, as mentioned above, the GFS then
decreases the chance of precipitation significantly after Sunday,
while the ECMWF holds on to a good chance of showers into Monday.
Again, with this kind of discrepancy this late in the forecast
period, I have decided to keep the chance for showers higher than
climatological normals and adjust as necessary as the models
hopefully come into better agreement.

The other concern with this system will be temperatures. Forecast
model compromise brings a much cooler airmass into the area with the
cut-off low/upper trough. As the system brings increasing
clouds/showers and a cold front into the area Friday into Saturday,
temperatures will cool from mostly 70s on Friday (about 10 degrees
above normal) into the mid 50s to mid 60s on Saturday (about 5 to 10
degrees below normal). With the faster exit of the system by the
GFS, it begins warming temperatures on Monday. However, have
maintained the trend of a lingering system and kept temperatures
similarly cool through the end of the period. This may cause some
mountains to get a rain/snow mix during the overnight hours.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  53  83  55 /  10   0  10  10
CTB  83  46  81  48 /   0   0  20  10
HLN  82  51  83  53 /  20  10  20  10
BZN  76  47  79  48 /  20  10  10  10
WEY  62  36  68  37 /  60  30  10   0
DLN  73  48  78  50 /  50  20  10  10
HVR  83  50  86  52 /   0   0   0  10
LWT  81  51  84  53 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 221503
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
903 AM MDT Mon Sep 22 2014

.UPDATE...

Today...Update to zones not planned...Very weak instability will
develop over Southwest Montana today. Some fairly high precipitable
water for this time of the year so some local heavy rain is
possible underneath slow moving storms. Current forecast on
track. Zelzer

&&


.AVIATION...
UPDATED 1135Z.
VFR conditions will generally prevail through the period, unless
otherwise noted. Moisture wrapping around a disturbance over SE
Idaho/SW Montana/NW Wyoming will bring areas of mid level cloudiness
as far north as a KGTF-KLWT line, but scattered showers and isolated
afternoon/evening thunderstorms will be limited to southwest Montana
(including KBZN). Some of these storms may produce brief heavy rain
and brief MVFR conditions. The clouds/showers/storms will decrease
and move east out of the area with the disturbance after 02Z. North
of the KGTF-KLWT line, only high cloudiness will pass overhead.
Winds will mostly be light, but they may become breezy at times out
of the west this afternoon/evening along the east slopes of the
Rockies.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 535 AM MDT Mon Sep 22 2014/

As of ~1000Z, cut-off mid-level low, within a much larger scale
upper-level ridge, was located along the Utah/Idaho border and was
slowly moving ENE as seen on WV imagery loop. Enough elevated
instability associated with the low for lightning strikes as far
north as northern Utah. Cyclonic flow around this low in the mid
levels will continue to advect higher mixing ratios into SW MT
into this aftn. Initial band of rain showers have developed in
area of PVA with -RA reported at W. Yellowstone and Dillon.

Today and Tonight...the level of tropospheric moisture in this
system is quite impressive, most of which likely originated from the
E Pacific off the coasts of S California and NW Mexico. Over SW MT,
precipitable water is forecast to be near 1 inch with 0.50 - 0.75
inch values expected over north-central MT. The 1 inch PWAT values
across SW MT are very anomalous for the end of Sept., and are 3-4
standard deviations above the mean or greater than the 99.5
percentile.

The high amount of moisture and weak mid-level steering flow
would point at the possibility for slow moving showers/storms and
the potential for localized flooding. However, the good news is
that weak/disorganized upper-level forcing for ascent will
inhibit widespread precip with this event. Nonetheless, isolated
areas in Southern Beaverhead, Madison, and Gallatin Counties may
experience hourly rainfall rates approaching or exceeding 0.50
inches/per hour during the morning and aftn hours. As usual,
valleys near mountainous terrain would be most prone to flash
flooding. Hi-Res NMM redevelops isolated to sct slow moving
showers and storms this aftn and evening with a focus over the SW
mountains.

Tuesday and Wednesday...Well above average temps will continue
along with mainly dry conditions as upper low pulls away. Even as
a large-scale trough approaches the Pacific NW, heights will
continue to rise to near 588 dam...1000-500mb thicknesses near 580
dam by Wednesday aftn. Highs over the lower elevations will range
from near 80F over the SW to the upper 80s close to 90F over
north-central/northeast portion of the forecast area. Uttech

Wednesday Night through Monday...High pressure aloft will begin to
move slowly east of the area on Thursday as a deep upper level
trough off the Pacific Northwest coast begins to move onshore.
The area will remain dry with temperatures similar to those
from Wednesday (15 to 20 degrees above normal).

Model differences occur as the trough moves onshore and toward
Montana. The GFS is about 24 hours faster than the ECMWF with the
progression of the trough. They both develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. However, the ECMWF weakens it into an open wave trough that
continues to move slower than the other models and lingers over
Montana into Monday. The GFS keeps the feature as a cut-off low and
moves it east over the central Rockies and out of the area Sunday
night into Monday. As a result, the models agree to initially bring
a chance of showers/thunderstorms into the area Thursday night into
Friday and continue it through Sunday. However, the placement of the
potentially heavier rainfall is not agreed upon, so have decided to
go with a broad-brushed high chance for showers/storms across the
area through the period. Again, as mentioned above, the GFS then
decreases the chance of precipitation significantly after Sunday,
while the ECMWF holds on to a good chance of showers into Monday.
Again, with this kind of discrepancy this late in the forecast
period, I have decided to keep the chance for showers higher than
climatological normals and adjust as necessary as the models
hopefully come into better agreement.

The other concern with this system will be temperatures. Forecast
model compromise brings a much cooler airmass into the area with the
cut-off low/upper trough. As the system brings increasing
clouds/showers and a cold front into the area Friday into Saturday,
temperatures will cool from mostly 70s on Friday (about 10 degrees
above normal) into the mid 50s to mid 60s on Saturday (about 5 to 10
degrees below normal). With the faster exit of the system by the
GFS, it begins warming temperatures on Monday. However, have
maintained the trend of a lingering system and kept temperatures
similarly cool through the end of the period. This may cause some
mountains to get a rain/snow mix during the overnight hours.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  53  83  55 /  10   0  10  10
CTB  83  46  81  48 /   0   0  20  10
HLN  82  51  83  53 /  20  10  20  10
BZN  76  47  79  48 /  20  10  10  10
WEY  62  36  68  37 /  60  30  10   0
DLN  73  48  78  50 /  50  20  10  10
HVR  83  50  86  52 /   0   0   0  10
LWT  81  51  84  53 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 221134
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
535 AM MDT Mon Sep 22 2014

.DISCUSSION...

As of ~1000Z, cut-off mid-level low, within a much larger scale
upper-level ridge, was located along the Utah/Idaho border and was
slowly moving ENE as seen on WV imagery loop. Enough elevated
instability associated with the low for lightning strikes as far
north as northern Utah. Cyclonic flow around this low in the mid
levels will continue to advect higher mixing ratios into SW MT
into this aftn. Initial band of rain showers have developed in
area of PVA with -RA reported at W. Yellowstone and Dillon.

Today and Tonight...the level of tropospheric moisture in this
system is quite impressive, most of which likely originated from the
E Pacific off the coasts of S California and NW Mexico. Over SW MT,
precipitable water is forecast to be near 1 inch with 0.50 - 0.75
inch values expected over north-central MT. The 1 inch PWAT values
across SW MT are very anomalous for the end of Sept., and are 3-4
standard deviations above the mean or greater than the 99.5
percentile.

The high amount of moisture and weak mid-level steering flow
would point at the possibility for slow moving showers/storms and
the potential for localized flooding. However, the good news is
that weak/disorganized upper-level forcing for ascent will
inhibit widespread precip with this event. Nonetheless, isolated
areas in Southern Beaverhead, Madison, and Gallatin Counties may
experience hourly rainfall rates approaching or exceeding 0.50
inches/per hour during the morning and aftn hours. As usual,
valleys near mountainous terrain would be most prone to flash
flooding. Hi-Res NMM redevelops isolated to sct slow moving
showers and storms this aftn and evening with a focus over the SW
mountains.

Tuesday and Wednesday...Well above average temps will continue
along with mainly dry conditions as upper low pulls away. Even as
a large-scale trough approaches the Pacific NW, heights will
continue to rise to near 588 dam...1000-500mb thicknesses near 580
dam by Wednesday aftn. Highs over the lower elevations will range
from near 80F over the SW to the upper 80s close to 90F over
north-central/northeast portion of the forecast area. Uttech

Wednesday Night through Monday...High pressure aloft will begin to
move slowly east of the area on Thursday as a deep upper level
trough off the Pacific Northwest coast begins to move onshore.
The area will remain dry with temperatures similar to those
from Wednesday (15 to 20 degrees above normal).

Model differences occur as the trough moves onshore and toward
Montana. The GFS is about 24 hours faster than the ECMWF with the
progression of the trough. They both develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. However, the ECMWF weakens it into an open wave trough that
continues to move slower than the other models and lingers over
Montana into Monday. The GFS keeps the feature as a cut-off low and
moves it east over the central Rockies and out of the area Sunday
night into Monday. As a result, the models agree to initially bring
a chance of showers/thunderstorms into the area Thursday night into
Friday and continue it through Sunday. However, the placement of the
potentially heavier rainfall is not agreed upon, so have decided to
go with a broad-brushed high chance for showers/storms across the
area through the period. Again, as mentioned above, the GFS then
decreases the chance of precipitation significantly after Sunday,
while the ECMWF holds on to a good chance of showers into Monday.
Again, with this kind of discrepancy this late in the forecast
period, I have decided to keep the chance for showers higher than
climatological normals and adjust as necessary as the models
hopefully come into better agreement.

The other concern with this system will be temperatures. Forecast
model compromise brings a much cooler airmass into the area with the
cut-off low/upper trough. As the system brings increasing
clouds/showers and a cold front into the area Friday into Saturday,
temperatures will cool from mostly 70s on Friday (about 10 degrees
above normal) into the mid 50s to mid 60s on Saturday (about 5 to 10
degrees below normal). With the faster exit of the system by the
GFS, it begins warming temperatures on Monday. However, have
maintained the trend of a lingering system and kept temperatures
similarly cool through the end of the period. This may cause some
mountains to get a rain/snow mix during the overnight hours.
Coulston

&&

.AVIATION...
UPDATED 1135Z.
VFR conditions will generally prevail through the period, unless
otherwise noted. Moisture wrapping around a disturbance over SE
Idaho/SW Montana/NW Wyoming will bring areas of mid level cloudiness
as far north as a KGTF-KLWT line, but scattered showers and isolated
afternoon/evening thunderstorms will be limited to southwest Montana
(including KBZN). Some of these storms may produce brief heavy rain
and brief MVFR conditions. The clouds/showers/storms will decrease
and move east out of the area with the disturbance after 02Z. North
of the KGTF-KLWT line, only high cloudiness will pass overhead.
Winds will mostly be light, but they may become breezy at times out
of the west this afternoon/evening along the east slopes of the
Rockies.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  53  83  55 /  10   0  10  10
CTB  83  46  81  48 /   0   0  20  10
HLN  82  51  83  53 /  20  10  20  10
BZN  76  47  79  48 /  20  10  10  10
WEY  62  36  68  37 /  60  30  10   0
DLN  73  48  78  50 /  50  20  10  10
HVR  83  50  86  52 /   0   0   0  10
LWT  81  51  84  53 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 221134
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
535 AM MDT Mon Sep 22 2014

.DISCUSSION...

As of ~1000Z, cut-off mid-level low, within a much larger scale
upper-level ridge, was located along the Utah/Idaho border and was
slowly moving ENE as seen on WV imagery loop. Enough elevated
instability associated with the low for lightning strikes as far
north as northern Utah. Cyclonic flow around this low in the mid
levels will continue to advect higher mixing ratios into SW MT
into this aftn. Initial band of rain showers have developed in
area of PVA with -RA reported at W. Yellowstone and Dillon.

Today and Tonight...the level of tropospheric moisture in this
system is quite impressive, most of which likely originated from the
E Pacific off the coasts of S California and NW Mexico. Over SW MT,
precipitable water is forecast to be near 1 inch with 0.50 - 0.75
inch values expected over north-central MT. The 1 inch PWAT values
across SW MT are very anomalous for the end of Sept., and are 3-4
standard deviations above the mean or greater than the 99.5
percentile.

The high amount of moisture and weak mid-level steering flow
would point at the possibility for slow moving showers/storms and
the potential for localized flooding. However, the good news is
that weak/disorganized upper-level forcing for ascent will
inhibit widespread precip with this event. Nonetheless, isolated
areas in Southern Beaverhead, Madison, and Gallatin Counties may
experience hourly rainfall rates approaching or exceeding 0.50
inches/per hour during the morning and aftn hours. As usual,
valleys near mountainous terrain would be most prone to flash
flooding. Hi-Res NMM redevelops isolated to sct slow moving
showers and storms this aftn and evening with a focus over the SW
mountains.

Tuesday and Wednesday...Well above average temps will continue
along with mainly dry conditions as upper low pulls away. Even as
a large-scale trough approaches the Pacific NW, heights will
continue to rise to near 588 dam...1000-500mb thicknesses near 580
dam by Wednesday aftn. Highs over the lower elevations will range
from near 80F over the SW to the upper 80s close to 90F over
north-central/northeast portion of the forecast area. Uttech

Wednesday Night through Monday...High pressure aloft will begin to
move slowly east of the area on Thursday as a deep upper level
trough off the Pacific Northwest coast begins to move onshore.
The area will remain dry with temperatures similar to those
from Wednesday (15 to 20 degrees above normal).

Model differences occur as the trough moves onshore and toward
Montana. The GFS is about 24 hours faster than the ECMWF with the
progression of the trough. They both develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. However, the ECMWF weakens it into an open wave trough that
continues to move slower than the other models and lingers over
Montana into Monday. The GFS keeps the feature as a cut-off low and
moves it east over the central Rockies and out of the area Sunday
night into Monday. As a result, the models agree to initially bring
a chance of showers/thunderstorms into the area Thursday night into
Friday and continue it through Sunday. However, the placement of the
potentially heavier rainfall is not agreed upon, so have decided to
go with a broad-brushed high chance for showers/storms across the
area through the period. Again, as mentioned above, the GFS then
decreases the chance of precipitation significantly after Sunday,
while the ECMWF holds on to a good chance of showers into Monday.
Again, with this kind of discrepancy this late in the forecast
period, I have decided to keep the chance for showers higher than
climatological normals and adjust as necessary as the models
hopefully come into better agreement.

The other concern with this system will be temperatures. Forecast
model compromise brings a much cooler airmass into the area with the
cut-off low/upper trough. As the system brings increasing
clouds/showers and a cold front into the area Friday into Saturday,
temperatures will cool from mostly 70s on Friday (about 10 degrees
above normal) into the mid 50s to mid 60s on Saturday (about 5 to 10
degrees below normal). With the faster exit of the system by the
GFS, it begins warming temperatures on Monday. However, have
maintained the trend of a lingering system and kept temperatures
similarly cool through the end of the period. This may cause some
mountains to get a rain/snow mix during the overnight hours.
Coulston

&&

.AVIATION...
UPDATED 1135Z.
VFR conditions will generally prevail through the period, unless
otherwise noted. Moisture wrapping around a disturbance over SE
Idaho/SW Montana/NW Wyoming will bring areas of mid level cloudiness
as far north as a KGTF-KLWT line, but scattered showers and isolated
afternoon/evening thunderstorms will be limited to southwest Montana
(including KBZN). Some of these storms may produce brief heavy rain
and brief MVFR conditions. The clouds/showers/storms will decrease
and move east out of the area with the disturbance after 02Z. North
of the KGTF-KLWT line, only high cloudiness will pass overhead.
Winds will mostly be light, but they may become breezy at times out
of the west this afternoon/evening along the east slopes of the
Rockies.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  53  83  55 /  10   0  10  10
CTB  83  46  81  48 /   0   0  20  10
HLN  82  51  83  53 /  20  10  20  10
BZN  76  47  79  48 /  20  10  10  10
WEY  62  36  68  37 /  60  30  10   0
DLN  73  48  78  50 /  50  20  10  10
HVR  83  50  86  52 /   0   0   0  10
LWT  81  51  84  53 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 221035
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
435 AM MDT Mon Sep 22 2014

.DISCUSSION...

As of ~1000Z, cut-off mid-level low, within a much larger scale
upper-level ridge, was located along the Utah/Idaho border and was
slowly moving ENE as seen on WV imagery loop. Enough elevated
instability associated with the low for lightning strikes as far
north as northern Utah. Cyclonic flow around this low in the mid
levels will continue to advect higher mixing ratios into SW MT
into this aftn. Initial band of rain showers have developed in
area of PVA with -RA reported at W. Yellowstone and Dillon.

Today and Tonight...the level of tropospheric moisture in this
system is quite impressive, most of which likely originated from the
E Pacific off the coasts of S California and NW Mexico. Over SW MT,
precipitable water is forecast to be near 1 inch with 0.50 - 0.75
inch values expected over north-central MT. The 1 inch PWAT values
across SW MT are very anomalous for the end of Sept., and are 3-4
standard deviations above the mean or greater than the 99.5
percentile.

The high amount of moisture and weak mid-level steering flow
would point at the possibility for slow moving showers/storms and
the potential for localized flooding. However, the good news is
that weak/disorganized upper-level forcing for ascent will
inhibit widespread precip with this event. Nonetheless, isolated
areas in Southern Beaverhead, Madison, and Gallatin Counties may
experience hourly rainfall rates approaching or exceeding 0.50
inches/per hour during the morning and aftn hours. As usual,
valleys near mountainous terrain would be most prone to flash
flooding. Hi-Res NMM redevelops isolated to sct slow moving
showers and storms this aftn and evening with a focus over the SW
mountains.

Tuesday and Wednesday...Well above average temps will continue
along with mainly dry conditions as upper low pulls away. Even as
a large-scale trough approaches the Pacific NW, heights will
continue to rise to near 588 dam...1000-500mb thicknesses near 580
dam by Wednesday aftn. Highs over the lower elevations will range
from near 80F over the SW to the upper 80s close to 90F over
north-central/northeast portion of the forecast area. Uttech

Wednesday Night through Monday...High pressure aloft will begin to
move slowly east of the area on Thursday as a deep upper level
trough off the Pacific Northwest coast begins to move onshore.
The area will remain dry with temperatures similar to those
from Wednesday (15 to 20 degrees above normal).

Model differences occur as the trough moves onshore and toward
Montana. The GFS is about 24 hours faster than the ECMWF with the
progression of the trough. They both develop a cut-off low over
California/Nevada and start to lift it northeast over the Great
Basin. However, the ECMWF weakens it into an open wave trough that
continues to move slower than the other models and lingers over
Montana into Monday. The GFS keeps the feature as a cut-off low and
moves it east over the central Rockies and out of the area Sunday
night into Monday. As a result, the models agree to initially bring
a chance of showers/thunderstorms into the area Thursday night into
Friday and continue it through Sunday. However, the placement of the
potentially heavier rainfall is not agreed upon, so have decided to
go with a broad-brushed high chance for showers/storms across the
area through the period. Again, as mentioned above, the GFS then
decreases the chance of precipitation significantly after Sunday,
while the ECMWF holds on to a good chance of showers into Monday.
Again, with this kind of discrepancy this late in the forecast
period, I have decided to keep the chance for showers higher than
climatological normals and adjust as necessary as the models
hopefully come into better agreement.

The other concern with this system will be temperatures. Forecast
model compromise brings a much cooler airmass into the area with the
cut-off low/upper trough. As the system brings increasing
clouds/showers and a cold front into the area Friday into Saturday,
temperatures will cool from mostly 70s on Friday (about 10 degrees
above normal) into the mid 50s to mid 60s on Saturday (about 5 to 10
degrees below normal). With the faster exit of the system by the
GFS, it begins warming temperatures on Monday. However, have
maintained the trend of a lingering system and kept temperatures
similarly cool through the end of the period. This may cause some
mountains to get a rain/snow mix during the overnight hours.
Coulston

&&

.AVIATION...
UPDATED 0445Z.
High pressure continues to provide dry and stable conditions. A
disturbance aloft over southern Idaho will continue to spread mid
and high clouds across extreme southwest Montana and high clouds
across central Montana. Isolated showers over extreme southwest
Montana, mainly along the border with Idaho, are possible after 09z.
Winds will remain light. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  53  83  55 /  10   0  10  10
CTB  83  46  81  48 /   0   0  20  10
HLN  82  51  83  53 /  20  10  20  10
BZN  76  47  79  48 /  20  10  10  10
WEY  62  36  68  37 /  60  30  10   0
DLN  73  48  78  50 /  50  20  10  10
HVR  83  50  86  52 /   0   0   0  10
LWT  81  51  84  53 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 220445
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MDT Sun Sep 21 2014

UPDATED AVIATION SECTION

.DISCUSSION...
No update to the forecast this evening as the going forecast covers
current conditions very well. Mid/upper level cloudiness continues to
stream northward into southwest MT from the Great Basin. Precip
shield remains over ID but is gradually shifting northward with
time as well. Chance PoPs overnight are sufficient. Foltz

&&

.AVIATION...
UPDATED 0445Z.
High pressure continues to provide dry and stable conditions. A
disturbance aloft over southern Idaho will continue to spread mid
and high clouds across extreme southwest Montana and high clouds
across central Montana. Isolated showers over extreme southwest
Montana, mainly along the border with Idaho, are possible after 09z.
Winds will remain light. VFR conditions prevail.

&&

.PREV DISCUSSION...
/ISSUED 545 PM MDT Sun Sep 21 2014/

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 220445
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MDT Sun Sep 21 2014

UPDATED AVIATION SECTION

.DISCUSSION...
No update to the forecast this evening as the going forecast covers
current conditions very well. Mid/upper level cloudiness continues to
stream northward into southwest MT from the Great Basin. Precip
shield remains over ID but is gradually shifting northward with
time as well. Chance PoPs overnight are sufficient. Foltz

&&

.AVIATION...
UPDATED 0445Z.
High pressure continues to provide dry and stable conditions. A
disturbance aloft over southern Idaho will continue to spread mid
and high clouds across extreme southwest Montana and high clouds
across central Montana. Isolated showers over extreme southwest
Montana, mainly along the border with Idaho, are possible after 09z.
Winds will remain light. VFR conditions prevail.

&&

.PREV DISCUSSION...
/ISSUED 545 PM MDT Sun Sep 21 2014/

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 220325
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
925 PM MDT Sun Sep 21 2014

.UPDATE...
No update to the forecast this evening as the going forecast covers
current conditions very well. Mid/upper level cloudiness continues to
stream northward into southwest MT from the Great Basin. Precip
shield remains over ID but is gradually shifting northward with
time as well. Chance PoPs overnight are sufficient. Foltz

&&


.AVIATION...
UPDATED 2345Z.
High pressure continues to provide dry and stable conditions. Skies
will remain clear overnight, the exception being extreme southwest
Montana where high clouds will continue to increase. Winds remain
light. VFR conditions prevail.

&&

.PREV DISCUSSION...
/ISSUED 545 PM MDT Sun Sep 21 2014/

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 220325
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
925 PM MDT Sun Sep 21 2014

.UPDATE...
No update to the forecast this evening as the going forecast covers
current conditions very well. Mid/upper level cloudiness continues to
stream northward into southwest MT from the Great Basin. Precip
shield remains over ID but is gradually shifting northward with
time as well. Chance PoPs overnight are sufficient. Foltz

&&


.AVIATION...
UPDATED 2345Z.
High pressure continues to provide dry and stable conditions. Skies
will remain clear overnight, the exception being extreme southwest
Montana where high clouds will continue to increase. Winds remain
light. VFR conditions prevail.

&&

.PREV DISCUSSION...
/ISSUED 545 PM MDT Sun Sep 21 2014/

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 212346
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
545 PM MDT Sun Sep 21 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 2345Z.
High pressure continues to provide dry and stable conditions. Skies
will remain clear overnight, the exception being extreme southwest
Montana where high clouds will continue to increase. Winds remain
light. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 212346
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
545 PM MDT Sun Sep 21 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 2345Z.
High pressure continues to provide dry and stable conditions. Skies
will remain clear overnight, the exception being extreme southwest
Montana where high clouds will continue to increase. Winds remain
light. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 212038
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
238 PM MDT Sun Sep 21 2014

.DISCUSSION...

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 1720Z.
An upper level ridge of high pressure will maintain dry conditions
with mainly clear skies through today with just some thin high
clouds spreading into extreme SW MT. The upper level ridge drifts
east tonight through Monday, allowing for clouds to further increase
over SW MT with dry and mainly clear conditions persisting farther
north. Surface winds will remain relatively light with a slight
uptick in SE winds over the plains this afternoon. VFR conditions
will prevail. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 212038
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
238 PM MDT Sun Sep 21 2014

.DISCUSSION...

Tonight through Tuesday...Main concern in the short term period
will center around the location of an upper level cutoff low. This
system is currently over Nevada and appears to be moving north-
northeast at a leisurely pace. Model solutions move the low into
southern Idaho by midnight then weaken and shear it eastward
during the overnight period. A residual low is expected to be over
Yellowstone NP early Monday morning and will move gradually
eastward along the Montana-Wyoming border. Main impact from this
system will be isolated showers near the Montana-Idaho border this
evening with showers becoming likely over the border mountains
after midnight and continuing through the day on Monday. Isolated
to scattered showers are possible as far north as Butte by early
morning and Helena by noon. The airmass is expected to become
unstable during the afternoon with precipitable water values up to
two standard deviations above seasonal averages across all of
Southwest Montana and southern portions of Central Montana. As a
result, scattered thunderstorms are expected to develop and could
bring a risk for heavy rains during the afternoon and evening
hours. Precipitation will diminish across the southern half of the
forecast area Monday night as the upper low continues to progress
eastward. This will leave Montana in a weakly unstable southwest
flow aloft with several embedded disturbances that will push
through western Montana Tuesday afternoon. This will bring another
chance for showers and isolated thunderstorms over the western
mountains with a few storms moving out over the plains during the
late afternoon. Temperatures are expected to be comfortably cool
during the overnight hours but afternoon highs will 10 to 15
degrees above seasonal averages. mpj

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 1720Z.
An upper level ridge of high pressure will maintain dry conditions
with mainly clear skies through today with just some thin high
clouds spreading into extreme SW MT. The upper level ridge drifts
east tonight through Monday, allowing for clouds to further increase
over SW MT with dry and mainly clear conditions persisting farther
north. Surface winds will remain relatively light with a slight
uptick in SE winds over the plains this afternoon. VFR conditions
will prevail. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  82  52  83 /   0  10  10  10
CTB  42  83  47  79 /   0   0  10  20
HLN  49  82  51  83 /  10  20  20  20
BZN  45  75  46  79 /  20  30  20  10
WEY  38  61  36  68 /  50  60  30  10
DLN  47  74  48  78 /  30  40  20  10
HVR  42  82  48  85 /   0   0   0  10
LWT  46  81  50  83 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 211720
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1120 AM MDT Sun Sep 21 2014

UPDATED AVIATION DISCUSSION

.UPDATE...High clouds from a cutoff upper level low over Central
California/Nevada are already moving up into far Southwest
Montana. Have updated to increase cloud cover from clear to partly
cloudy in this region. Remainder of the forecast looks to be in
good shape with a warm and mostly sunny day on tap. mpj

&&

.AVIATION...
UPDATED 1720Z.
An upper level ridge of high pressure will maintain dry conditions
with mainly clear skies through today with just some thin high
clouds spreading into extreme SW MT. The upper level ridge drifts
east tonight through Monday, allowing for clouds to further increase
over SW MT with dry and mainly clear conditions persisting farther
north. Surface winds will remain relatively light with a slight
uptick in SE winds over the plains this afternoon. VFR conditions
will prevail. Hoenisch

&&

.PREV DISCUSSION...
/ISSUED 508 AM MDT Sun Sep 21 2014/

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 211720
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1120 AM MDT Sun Sep 21 2014

UPDATED AVIATION DISCUSSION

.UPDATE...High clouds from a cutoff upper level low over Central
California/Nevada are already moving up into far Southwest
Montana. Have updated to increase cloud cover from clear to partly
cloudy in this region. Remainder of the forecast looks to be in
good shape with a warm and mostly sunny day on tap. mpj

&&

.AVIATION...
UPDATED 1720Z.
An upper level ridge of high pressure will maintain dry conditions
with mainly clear skies through today with just some thin high
clouds spreading into extreme SW MT. The upper level ridge drifts
east tonight through Monday, allowing for clouds to further increase
over SW MT with dry and mainly clear conditions persisting farther
north. Surface winds will remain relatively light with a slight
uptick in SE winds over the plains this afternoon. VFR conditions
will prevail. Hoenisch

&&

.PREV DISCUSSION...
/ISSUED 508 AM MDT Sun Sep 21 2014/

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 211513
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
913 AM MDT Sun Sep 21 2014

.UPDATE...High clouds from a cutoff upper level low over Central
California/Nevada are already moving up into far Southwest
Montana. Have updated to increase cloud cover from clear to partly
cloudy in this region. Remainder of the forecast looks to be in
good shape with a warm and mostly sunny day on tap. mpj

&&

.AVIATION...
UPDATED 1108Z.
VFR conditions will continue through at least 12Z Monday. High
pressure aloft will keep most of the area clear through the period.
However, a disturbance approaching from the southwest will bring
isolated showers with a slight chance of thunderstorms to southwest
Montana after 00Z, possibly reaching KBZN after 06Z. Southeast winds
will likely increase to around 10 kt today over the plains, but
mountain valleys will continue to have light winds.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 508 AM MDT Sun Sep 21 2014/

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 211513
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
913 AM MDT Sun Sep 21 2014

.UPDATE...High clouds from a cutoff upper level low over Central
California/Nevada are already moving up into far Southwest
Montana. Have updated to increase cloud cover from clear to partly
cloudy in this region. Remainder of the forecast looks to be in
good shape with a warm and mostly sunny day on tap. mpj

&&

.AVIATION...
UPDATED 1108Z.
VFR conditions will continue through at least 12Z Monday. High
pressure aloft will keep most of the area clear through the period.
However, a disturbance approaching from the southwest will bring
isolated showers with a slight chance of thunderstorms to southwest
Montana after 00Z, possibly reaching KBZN after 06Z. Southeast winds
will likely increase to around 10 kt today over the plains, but
mountain valleys will continue to have light winds.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 508 AM MDT Sun Sep 21 2014/

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 211109
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
508 AM MDT Sun Sep 21 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 1108Z.
VFR conditions will continue through at least 12Z Monday. High
pressure aloft will keep most of the area clear through the period.
However, a disturbance approaching from the southwest will bring
isolated showers with a slight chance of thunderstorms to southwest
Montana after 00Z, possibly reaching KBZN after 06Z. Southeast winds
will likely increase to around 10 kt today over the plains, but
mountain valleys will continue to have light winds.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 211109
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
508 AM MDT Sun Sep 21 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 1108Z.
VFR conditions will continue through at least 12Z Monday. High
pressure aloft will keep most of the area clear through the period.
However, a disturbance approaching from the southwest will bring
isolated showers with a slight chance of thunderstorms to southwest
Montana after 00Z, possibly reaching KBZN after 06Z. Southeast winds
will likely increase to around 10 kt today over the plains, but
mountain valleys will continue to have light winds.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 210951
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
351 AM MDT Sun Sep 21 2014

.DISCUSSION...

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 0440Z.
High pressure continues over the area. Skies will be clear with
light surface winds. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 210951
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
351 AM MDT Sun Sep 21 2014

.DISCUSSION...

Today through Tuesday...The upper level ridge of high pressure
over Montana will keep the area mostly sunny and dry today as
temperatures warm to around 10 degrees above normal. Forecast
models continue to indicate that the cutoff low currently over
California and Nevada will be lifted northeast toward Montana by
a deep trough over the eastern Pacific. The chance for scattered
showers and thunderstorms will increase over southwest Montana
tonight into Monday due to the moisture and instability along the
leading edge of this system. Models also indicate that some storms
could develop as far north as the mountain areas of central and
northwest Montana, so have continued the mention of storms there.
Instability with this system remains a bit on the weak side, so
the chance for strong to severe storms remains low, but brief
heavy rain is possible. Temperatures will warm another 5 degrees
or so over today across most of the area, but clouds/storms in
southwest Montana will keep high temperatures similar to those
today. The system will weaken and become more of an open wave
Monday afternoon then move east of the area Monday night, for a
decreasing chance of showers and storms. High pressure aloft will
rebuild from the southwestern United States as the deep trough
mentioned above will approaches the CONUS from the west. The
resulting increasing southwesterly flow aloft will bring breezy
westerly winds to the area, along with a slight chance of
thunderstorm development over the mountains. Temperatures will
also cool a few degrees as a weak disturbance moves through the
area.  Coulston

Tuesday Night through Sunday...An upper level ridge will amplify
over the region early Wednesday while temperatures warm to well
above seasonal averages. The ridge axis moves away to the east on
Thursday as a deep trof moves ashore over the Pacific Northwest.
Wednesday should be the warmest day of the week ahead, and only
slightly cooler on Thursday. Isolated showers and thunderstorms will
begin to develop Thursday night with decreasing stability over the
higher terrain of western and southwest Montana.

Confidence is growing in a solution of widespread showers and
thunderstorms on Friday evening. However, model differences begin to
develop Friday night. The GFS moves the trof through the northern
Rockies more rapidly than the ECMWF and GEM...both of which split
the trof and dig it further south along the west coast. Have raised
POPs on Friday night and Saturday, but keeping below the likely
category given uncertainties in timing and position. Temperatures
will drop back into the 60s as the trof swings through over the
weekend. At this time, it appears any snow would be limited to the
highest mountain peaks Saturday night.
Nutter

&&

.AVIATION...
UPDATED 0440Z.
High pressure continues over the area. Skies will be clear with
light surface winds. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  50  83  55 /   0   0  10  10
CTB  77  44  83  49 /   0   0  10  10
HLN  81  51  83  52 /   0  10  20  10
BZN  77  47  76  47 /   0  20  40  20
WEY  73  39  63  37 /  10  50  60  30
DLN  78  52  75  49 /  10  30  40  20
HVR  79  45  83  51 /   0   0   0  10
LWT  76  49  82  51 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 210440
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1040 PM MDT Sat Sep 20 2014

UPDATED AVIATION SECTION

.DISCUSSION...
No update necessary this evening. Upper ridge will remain in place
overnight providing clear skies and light winds. High pressure
persists Sunday for yet another day of dry and stable conditions.
Temperatures overnight look good.

&&

.AVIATION...
UPDATED 0440Z.
High pressure continues over the area. Skies will be clear with
light surface winds. VFR conditions prevail.

&&

.PREV DISCUSSION...Issued 239 PM MDT Sat Sep 20 2014

Tonight through Monday...Forecast area will remain under the
influence of an upper level ridge tonight and Sunday for mostly
clear and dry conditions. Temperatures for tonight and Sunday will
remain above seasonal averages and winds will be generally light
as they gradually veer around to the south-southeast. Increasing
uncertainty in the forecast develops Sunday evening as an upper
level closed low, currently over the Central California coast,
drifts northeast and approaches the Yellowstone region. Latest
models weaken this feature into an open trough as it approaches
Southwest Montana Sunday night, then shear it eastward on
Monday. Biggest question will be how far north will scattered
showers and thunderstorms associated with the upper low move.
Morning model runs suggest that isolated precipitation could move
as far north as the Little Belt Mountains by Monday afternoon.
Stability parameters indicate that isolated thunderstorms may even
form over mountainous areas as far north as Glacier Park. Have
therefore tweaked forecast pops for Monday a bit higher in the
north. However, it should be noted, that the likelihood for any
strong to severe storms appears low at this time. mpj

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  77  50  83 /   0   0   0  10
CTB  42  76  44  83 /   0   0   0  10
HLN  46  80  50  83 /   0   0  10  20
BZN  41  76  46  78 /   0   0  20  30
WEY  34  72  39  64 /   0  10  50  50
DLN  45  78  51  77 /   0  10  30  40
HVR  43  79  45  83 /   0   0   0  10
LWT  45  75  48  82 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls













000
FXUS65 KTFX 210250
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
850 PM MDT Sat Sep 20 2014

.DISCUSSION...
No update necessary this evening. Upper ridge will remain in place
overnight providing clear skies and light winds. High pressure
persists Sunday for yet another day of dry and stable conditions.
Temperatures overnight look good.

&&

.AVIATION...
UPDATED 2335Z.
High pressure will persist over the area providing dry and stable
conditions. Skies will be clear with light surface winds. VFR
conditions prevail.

&&

.PREV DISCUSSION...Issued 239 PM MDT Sat Sep 20 2014

Tonight through Monday...Forecast area will remain under the
influence of an upper level ridge tonight and Sunday for mostly
clear and dry conditions. Temperatures for tonight and Sunday will
remain above seasonal averages and winds will be generally light
as they gradually veer around to the south-southeast. Increasing
uncertainty in the forecast develops Sunday evening as an upper
level closed low, currently over the Central California coast,
drifts northeast and approaches the Yellowstone region. Latest
models weaken this feature into an open trough as it approaches
Southwest Montana Sunday night, then shear it eastward on
Monday. Biggest question will be how far north will scattered
showers and thunderstorms associated with the upper low move.
Morning model runs suggest that isolated precipitation could move
as far north as the Little Belt Mountains by Monday afternoon.
Stability parameters indicate that isolated thunderstorms may even
form over mountainous areas as far north as Glacier Park. Have
therefore tweaked forecast pops for Monday a bit higher in the
north. However, it should be noted, that the likelihood for any
strong to severe storms appears low at this time. mpj

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  77  50  83 /   0   0   0  10
CTB  42  76  44  83 /   0   0   0  10
HLN  46  80  50  83 /   0   0  10  20
BZN  41  76  46  78 /   0   0  20  30
WEY  34  72  39  64 /   0  10  50  50
DLN  45  78  51  77 /   0  10  30  40
HVR  43  79  45  83 /   0   0   0  10
LWT  45  75  48  82 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
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www.facebook.com/NWSGreatFalls











000
FXUS65 KTFX 210250
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
850 PM MDT Sat Sep 20 2014

.DISCUSSION...
No update necessary this evening. Upper ridge will remain in place
overnight providing clear skies and light winds. High pressure
persists Sunday for yet another day of dry and stable conditions.
Temperatures overnight look good.

&&

.AVIATION...
UPDATED 2335Z.
High pressure will persist over the area providing dry and stable
conditions. Skies will be clear with light surface winds. VFR
conditions prevail.

&&

.PREV DISCUSSION...Issued 239 PM MDT Sat Sep 20 2014

Tonight through Monday...Forecast area will remain under the
influence of an upper level ridge tonight and Sunday for mostly
clear and dry conditions. Temperatures for tonight and Sunday will
remain above seasonal averages and winds will be generally light
as they gradually veer around to the south-southeast. Increasing
uncertainty in the forecast develops Sunday evening as an upper
level closed low, currently over the Central California coast,
drifts northeast and approaches the Yellowstone region. Latest
models weaken this feature into an open trough as it approaches
Southwest Montana Sunday night, then shear it eastward on
Monday. Biggest question will be how far north will scattered
showers and thunderstorms associated with the upper low move.
Morning model runs suggest that isolated precipitation could move
as far north as the Little Belt Mountains by Monday afternoon.
Stability parameters indicate that isolated thunderstorms may even
form over mountainous areas as far north as Glacier Park. Have
therefore tweaked forecast pops for Monday a bit higher in the
north. However, it should be noted, that the likelihood for any
strong to severe storms appears low at this time. mpj

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  77  50  83 /   0   0   0  10
CTB  42  76  44  83 /   0   0   0  10
HLN  46  80  50  83 /   0   0  10  20
BZN  41  76  46  78 /   0   0  20  30
WEY  34  72  39  64 /   0  10  50  50
DLN  45  78  51  77 /   0  10  30  40
HVR  43  79  45  83 /   0   0   0  10
LWT  45  75  48  82 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls










000
FXUS65 KTFX 202334
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
535 PM MDT Sat Sep 20 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Tonight through Monday...Forecast area will remain under the
influence of an upper level ridge tonight and Sunday for mostly
clear and dry conditions. Temperatures for tonight and Sunday will
remain above seasonal averages and winds will be generally light
as they gradually veer around to the south-southeast. Increasing
uncertainty in the forecast develops Sunday evening as an upper
level closed low, currently over the Central California coast,
drifts northeast and approaches the Yellowstone region. Latest
models weaken this feature into an open trough as it approaches
Southwest Montana Sunday night, then shear it eastward on
Monday. Biggest question will be how far north will scattered
showers and thunderstorms associated with the upper low move.
Morning model runs suggest that isolated precipitation could move
as far north as the Little Belt Mountains by Monday afternoon.
Stability parameters indicate that isolated thunderstorms may even
form over mountainous areas as far north as Glacier Park. Have
therefore tweaked forecast pops for Monday a bit higher in the
north. However, it should be noted, that the likelihood for any
strong to severe storms appears low at this time. mpj

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 2335Z.
High pressure will persist over the area providing dry and stable
conditions. Skies will be clear with light surface winds. VFR
conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  77  50  83 /   0   0   0  10
CTB  42  76  44  83 /   0   0   0  10
HLN  46  80  50  83 /   0   0  10  20
BZN  41  76  46  78 /   0   0  20  30
WEY  34  72  39  64 /   0  10  50  50
DLN  45  78  51  77 /   0  10  30  40
HVR  43  79  45  83 /   0   0   0  10
LWT  45  75  48  82 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 202039
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
239 PM MDT Sat Sep 20 2014

.DISCUSSION...

Tonight through Monday...Forecast area will remain under the
influence of an upper level ridge tonight and Sunday for mostly
clear and dry conditions. Temperatures for tonight and Sunday will
remain above seasonal averages and winds will be generally light
as they gradually veer around to the south-southeast. Increasing
uncertainty in the forecast develops Sunday evening as an upper
level closed low, currently over the Central California coast,
drifts northeast and approaches the Yellowstone region. Latest
models weaken this feature into an open trough as it approaches
Southwest Montana Sunday night, then shear it eastward on
Monday. Biggest question will be how far north will scattered
showers and thunderstorms associated with the upper low move.
Morning model runs suggest that isolated precipitation could move
as far north as the Little Belt Mountains by Monday afternoon.
Stability parameters indicate that isolated thunderstorms may even
form over mountainous areas as far north as Glacier Park. Have
therefore tweaked forecast pops for Monday a bit higher in the
north. However, it should be noted, that the likelihood for any
strong to severe storms appears low at this time. mpj

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 1715Z.
An upper level ridge of high pressure over the Northern Rockies and
surface high pressure over the Northern Plains will maintain mainly
clear skies with relatively light surface winds through Sunday. VFR
conditions will prevail. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  77  50  83 /   0   0   0  10
CTB  42  76  44  83 /   0   0   0  10
HLN  46  80  50  83 /   0   0  10  20
BZN  41  76  46  78 /   0   0  20  30
WEY  34  72  39  64 /   0  10  50  50
DLN  45  78  51  77 /   0  10  30  40
HVR  43  79  45  83 /   0   0   0  10
LWT  45  75  48  82 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 202039
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
239 PM MDT Sat Sep 20 2014

.DISCUSSION...

Tonight through Monday...Forecast area will remain under the
influence of an upper level ridge tonight and Sunday for mostly
clear and dry conditions. Temperatures for tonight and Sunday will
remain above seasonal averages and winds will be generally light
as they gradually veer around to the south-southeast. Increasing
uncertainty in the forecast develops Sunday evening as an upper
level closed low, currently over the Central California coast,
drifts northeast and approaches the Yellowstone region. Latest
models weaken this feature into an open trough as it approaches
Southwest Montana Sunday night, then shear it eastward on
Monday. Biggest question will be how far north will scattered
showers and thunderstorms associated with the upper low move.
Morning model runs suggest that isolated precipitation could move
as far north as the Little Belt Mountains by Monday afternoon.
Stability parameters indicate that isolated thunderstorms may even
form over mountainous areas as far north as Glacier Park. Have
therefore tweaked forecast pops for Monday a bit higher in the
north. However, it should be noted, that the likelihood for any
strong to severe storms appears low at this time. mpj

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 1715Z.
An upper level ridge of high pressure over the Northern Rockies and
surface high pressure over the Northern Plains will maintain mainly
clear skies with relatively light surface winds through Sunday. VFR
conditions will prevail. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  77  50  83 /   0   0   0  10
CTB  42  76  44  83 /   0   0   0  10
HLN  46  80  50  83 /   0   0  10  20
BZN  41  76  46  78 /   0   0  20  30
WEY  34  72  39  64 /   0  10  50  50
DLN  45  78  51  77 /   0  10  30  40
HVR  43  79  45  83 /   0   0   0  10
LWT  45  75  48  82 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
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000
FXUS65 KTFX 201715
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1115 AM MDT Sat Sep 20 2014

.DISCUSSION...An upper level ridge continues to develop along the
West Coast today. As a result, scattered high clouds over
eastern portions of my forecast area are being shunted eastward
and diminishing. The remainder of the weekend is expected to be
dry and mostly clear with warmer temperatures on Sunday. Going
forecast is in good shape. Made only minor changes to winds
based upon current conditions and this did not affect wording in
any noticeable way. mpj

&&

.AVIATION...
UPDATED 1715Z.
An upper level ridge of high pressure over the Northern Rockies and
surface high pressure over the Northern Plains will maintain mainly
clear skies with relatively light surface winds through Sunday. VFR
conditions will prevail. Hoenisch

&&

.PREV DISCUSSION...
/ISSUED 610 AM MDT Sat Sep 20 2014/

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 201715
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1115 AM MDT Sat Sep 20 2014

.DISCUSSION...An upper level ridge continues to develop along the
West Coast today. As a result, scattered high clouds over
eastern portions of my forecast area are being shunted eastward
and diminishing. The remainder of the weekend is expected to be
dry and mostly clear with warmer temperatures on Sunday. Going
forecast is in good shape. Made only minor changes to winds
based upon current conditions and this did not affect wording in
any noticeable way. mpj

&&

.AVIATION...
UPDATED 1715Z.
An upper level ridge of high pressure over the Northern Rockies and
surface high pressure over the Northern Plains will maintain mainly
clear skies with relatively light surface winds through Sunday. VFR
conditions will prevail. Hoenisch

&&

.PREV DISCUSSION...
/ISSUED 610 AM MDT Sat Sep 20 2014/

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 201557
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
957 AM MDT Sat Sep 20 2014

.DISCUSSION...An upper level ridge continues to develop along the
West Coast today. As a result, scattered high clouds over
eastern portions of my forecast area are being shunted eastward
and diminishing. The remainder of the weekend is expected to be
dry and mostly clear with warmer temperatures on Sunday. Going
forecast is in good shape. Made only minor changes to winds
based upon current conditions and this did not affect wording in
any noticeable way. mpj

&&

.AVIATION...
UPDATED 1210Z.
VFR conditions are expected to continue through at least 12Z Sunday.
A generally dry northwest flow aloft will decrease and become more
westerly through the period as high pressure builds into the area,
allowing a few high clouds to move over the area. Surface high
pressure will also move southeast across eastern Montana, shifting
light northwesterly surface winds more southeasterly after 20Z.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 610 AM MDT Sat Sep 20 2014/

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 201557
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
957 AM MDT Sat Sep 20 2014

.DISCUSSION...An upper level ridge continues to develop along the
West Coast today. As a result, scattered high clouds over
eastern portions of my forecast area are being shunted eastward
and diminishing. The remainder of the weekend is expected to be
dry and mostly clear with warmer temperatures on Sunday. Going
forecast is in good shape. Made only minor changes to winds
based upon current conditions and this did not affect wording in
any noticeable way. mpj

&&

.AVIATION...
UPDATED 1210Z.
VFR conditions are expected to continue through at least 12Z Sunday.
A generally dry northwest flow aloft will decrease and become more
westerly through the period as high pressure builds into the area,
allowing a few high clouds to move over the area. Surface high
pressure will also move southeast across eastern Montana, shifting
light northwesterly surface winds more southeasterly after 20Z.
Coulston

&&

.PREV DISCUSSION...
/ISSUED 610 AM MDT Sat Sep 20 2014/

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 201212
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
610 AM MDT Sat Sep 20 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 1210Z.
VFR conditions are expected to continue through at least 12Z Sunday.
A generally dry northwest flow aloft will decrease and become more
westerly through the period as high pressure builds into the area,
allowing a few high clouds to move over the area. Surface high
pressure will also move southeast across eastern Montana, shifting
light northwesterly surface winds more southeasterly after 20Z.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 201212
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
610 AM MDT Sat Sep 20 2014

UPDATED AVIATION SECTION

.DISCUSSION...

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 1210Z.
VFR conditions are expected to continue through at least 12Z Sunday.
A generally dry northwest flow aloft will decrease and become more
westerly through the period as high pressure builds into the area,
allowing a few high clouds to move over the area. Surface high
pressure will also move southeast across eastern Montana, shifting
light northwesterly surface winds more southeasterly after 20Z.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 200934
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
334 AM MDT Sat Sep 20 2014

.DISCUSSION...

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 0450Z.
Dry northwest flow aloft will continue overnight as well as Saturday
as high pressure builds over the western U.S. Winds will remain
generally light. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 200934
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
334 AM MDT Sat Sep 20 2014

.DISCUSSION...

Today through Monday...The current gusty west winds across north
central Montana, especially along the Rocky Mountain Front, will
decrease today as a shortwave trough aloft and an accompanying
weak surface boundary both move east out of the area. Otherwise,
high pressure aloft will build into the area in the wake of the
shortwave, which will steadily warm temperatures. Highs around 5
degrees above normal today will warm to between 10 and 15 degrees
above normal by Monday. The subsidence from the high pressure
will also keep most of the area dry through the period. However, a
cut off low pressure area, currently along the California coast,
will be lifted northeast by large upper level trough approaching
the Pacific coast. This cut off low will move into southern Idaho
Sunday night then east into Wyoming on Monday. This system will
drag Pacific moisture from off the Mexican coast north into
Montana, bringing a good chance of showers and thunderstorms to
southern Montana Sunday night into Monday. Instability is moderate
at best, so strong thunderstorms with small hail are possible but
uncertain at this time. However, moisture may be significant
enough to cause brief heavy rainfall with storms.
Coulston

Monday Night through Saturday...Remnants of the weakening cut-off
low drift away to the east as an upper level ridge begins to
amplify over the Intermountain west. This will result in fair and
warmer conditions through early Thursday. The upper ridge axis
moves east of the region on Thursday as heights begin to fall
ahead of a broad synoptic trof advancing through the Pacific
Northwest. Isolated showers and thunderstorms will begin to
develop Thursday evening with decreasing stability over the higher
terrain of western and southwest Montana.

Models maintain overall good consistency through Friday. The GFS
moves the trof axis a bit faster than the ECMWF. Ensemble means and
extended guidance from NWS WPC tends to favor the GFS guidance for
the end of the forecast period. In general the forecast reflects
temperatures returning to seasonal averages with above average
chances for precipitation.
Nutter

&&

.AVIATION...
UPDATED 0450Z.
Dry northwest flow aloft will continue overnight as well as Saturday
as high pressure builds over the western U.S. Winds will remain
generally light. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  77  49 /   0   0   0   0
CTB  71  42  76  43 /   0   0   0   0
HLN  77  46  79  49 /   0   0   0  10
BZN  74  41  75  46 /   0   0   0  20
WEY  70  33  71  38 /   0   0  10  50
DLN  75  45  77  51 /   0   0  10  20
HVR  74  44  78  45 /   0   0   0   0
LWT  71  45  75  47 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






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