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000
FXUS65 KGGW 232035
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
235 PM MDT MON MAY 23 2016

.SHORT TERM...for northeast Montana...tonight through Wed...
The main driver of the weather over northeast Montana tonight will
continue to be the low pressure system centered over southern
Saskatchewan. The gusty west winds are expected to diminish after
sunset as we lose the surface heating induced vertical mixing.
Showers should diminish for most of the area overnight, with
lingering chances for a few rain showers near the Canadian border
and our western areas.

Tuesday brings increasing rain chances from west to east
throughout the day. A shortwave impulse within the circulation of
the low pressure system will provide enough moisture and
instability for a few isolated thunderstorms to develop. As this
rotates around the retreating upper low...scattered rain showers
and isolated thunderstorms are possible throughout the area into
Wednesday. Most of the storms should occur in the afternoon and
evening when surface heating is at a maximum. With the relatively
low CAPE values, most of our precipitation should be in the form
of rain showers and any thunderstorm that does develop over the
next couple of days should not become severe.

Hickford


.LONG TERM...Wed night through Mon...

Update: The going forecast is in excellent shape depicting
unsettled conditions under the influence of an upper trough. Only
tweak was an overall trend toward the latest model consensus.
Gilchrist

Previous long term discussion:
Extended period will be dominated by a longwave trof over the
western CONUS. Remnants of the low pressure currently over the
Cypress Hills lingers in southern Saskatchewan through the end of
the week. By the weekend another shortwave low dives into the
Pacific Northwest. Models differ greatly on the track of this low
early next week, for very low confidence at the end of the
forecast period.

Overall the pattern will lead to slightly above normal
temperatures with unsettled weather. Some weak shortwave ridging
as the low digs into the Pacific Northwest could result in
diminishing shower potential Thursday before southwest flow
develops deformation zone across central Montana on Friday. Ebert


&&

.AVIATION...
Synopsis: The region will remain under the influence of a
large upper level trough of low pressure over the next several
days. This upper trough will make for unsettled conditions at
times, but bye and large conditions will be vfr.

Cigs: Bkn mid level clouds.

Visibility: Unrestricted.

Winds: Gusty and southwesterly this afternoon decreasing to
around 10kts around sunset.

Gilchrist

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 10 PM MDT this evening For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow





000
FXUS65 KGGW 230919
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
319 AM MDT MON MAY 23 2016

.SHORT TERM...for northeast Montana...today through Wed...

Main driver of the sensible weather across northeast Montana today
will be the stalled low pressure center now over southern
Saskatchewan. Positioning and a tight pressure gradient will
direct strong and gusty west winds across the CWA today. Expecting
sustained winds around 20 to 25 mph with some gusts in excess of
35 mph. Have decided to go ahead and issue another Lake Wind
Advisory for Fort Peck Lake today from 8AM to 10 PM. That should
allow for a little bit of buffer time on the advisory at the
beginning and end and make for convenient updates or early
cancellations if/when necessary.

Near and short term model consensus is a bit better than it was
yesterday and seems to have at least a moderate handle on how the
precipitation is expected to evolve over the next 2 or 3 days.

Along with gusty winds, the Saskatchewan Low will push scattered
rain showers with a few small thunderstorms across northeast
Montana today from the west and northwest, especially during the
daylight and peak-heating hours. HRRR model seems to have the
most realistic depiction of this so leaned a little bit more on
that model for today`s precip.

Tonight through Tuesday, the overall precip coverage will be less
with a few lingering rain showers over our northwestern and
northern zones. This evolution correlates well with the
Saskatchewan Low weakening and finally moving eastward and
clipping our international border as it goes. This basically would
signal the end of the first round of precip in the short term. Up
to 0.25 inch of rain will be possible over our northwestern zones
and hardly any for our southeastern zones.

From late Tuesday through Wednesday, a remnant low pressure lobe
from the Canadian Rockies and the Montana Rockies will pivot
around the base of the retreating low center and draw up more
favorable moisture and instability to bring showers and
thunderstorms up to our area from the south. Model consensus
precip amounts are a little less certain for this time frame, but
the overall progression is intact. Thinking for this round of
precip is up to 0.40 inch for our southeastern zones and trace or
none for our northwestern zones.

Instability models show that CAPE values will be on the lighter
side and limited mainly to the edges of our CWA. So, while
thunderstorms could be possible over the next 2 to 3 days, think
that scattered rain showers would be much more likely with the off
and on chance of a small sub-severe thunderstorm or two.
BMickelson

.LONG TERM...Wed night through Mon...

Extended period will be dominated by a long-wave trof over the
western CONUS. Remnants of the low pressure currently over the
Cypress Hills lingers in southern Saskatchewan through the end of
the week. By the weekend another shortwave low dives into the
Pacific Northwest. Models differ greatly on the track of this low
early next week, for very low confidence at the end of the
forecast period.

Overall the pattern will lead to slightly above normal
temperatures with unsettled weather. Some weak shortwave ridging
as the low digs into the Pacific Northwest could result in
diminishing shower potential Thursday before southwest flow
develops deformation zone across central Montana on Friday. Ebert


&&

.AVIATION...

An upper low continues to spin from southern Alberta into southern
Saskatchewan today. Isolated showers and thunderstorms are
possible this afternoon and early evening as well as virga
downdrafts. KGGW is the most likely site to be impacted. Otherwise
expect VFR conditions.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from 8 AM this morning to 10 PM MDT this
evening For Fort Peck Lake for Central and Southeast Phillips...
Central and Southern Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow





000
FXUS65 KGGW 221502
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
902 AM MDT SUN MAY 22 2016

.SHORT TERM...for northeast Montana...today through Tue...

Skies have cleared out this morning, but cumulus clouds will build up
again by noon as things heat up. overall, the forecast has this
covered well. rest of forecast looked to be in good shape. TFJ

Previous Discussion...
Upper low has moved into the Northern Rockies with the omega
block ridge axis now near the Dakotas/Minnesota border. Surface
boundary just into the western Dakotas with line of showers over
the eastern zones. The entire system will continue to shift east
today as the upper low lifts toward Saskatchewan. While the omega
block breaks down over the next few days, the longwave trof will
linger over the western states through most of the week.

Cooler weather expected for the next few days with the upper trof
over the region. Moisture wrapped around the stalled Canadian low
will bring a threat of showers or thunderstorms to mainly
north central Montana, but storms could spread into eastern
Montana with the cooler unstable airmass. The proximity of the
stacked low will also result in increased winds during the
afternoon so have issued a lake wind advisory for Fort Peck Lake
this afternoon. Winds expected to be stronger on Monday with the
low spinning over southern Saskatchewan. Low begins to weaken by
Tuesday so expect diminishing winds. Ebert


.LONG TERM...Tue night through Sun...

The entire extended forecast period is complicated with a messy,
disorganized weather pattern. Off-and-on scattered chances for
rain showers and a few thunderstorms would be the best way to
describe it.

A large-scale general or overall trough stretches over the western
states and the high plains regions. Some smaller-scale embedded
short-wave troughs and/or small low pressure centers meander
around the neighborhood of the bigger trough.

This predominance of some version of low pressure influence will
simply add to the multiple forecast periods of northeast Montana not
quite being free from the threat of precipitation. Consequently,
model data consensus is not extremely helpful for confidence in
timing and placement of the resulting rain showers and
thunderstorms, other than to imply scattered, disorganized
chances, especially Wednesday afternoon through Friday afternoon.

BMickelson

&&

.AVIATION...

Synopsis: vfr cumulus clouds are expected to build into the
afternoon but a dry afternoon is expected.

Winds: Winds will increase from the southwest to around 20 knots
with a few higher gusts, creating some runway crosswind concerns.
Expect winds to diminish again after sunset.

BMickelson/TFJ


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 8 PM MDT this evening For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow





000
FXUS65 KGGW 212355
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
555 PM MDT SAT MAY 21 2016

.SHORT TERM...for northeast Montana...tonight through Mon...
...Severe thunderstorm watch continues for much of NE Montana
through 9 PM this evening...

6PM Update...

Given convective trends, severe thunderstorm watch has been
extended to include McCone, Richland, Dawson, Prairie, and Wibaux
Counties. Damaging winds and large hail remain possible with any
storms through this evening. People should continue to monitor the
latest warnings and be prepared to seek safety. Maliawco

Previous Discussion...

Area of thunderstorms have begun this afternoon. At 2pm, extend
entend from Stanford in central montana south to east of
Livingston. Much of this area is moving northeast and should
begin affecting the western zones later this afternoon. With
cloudcover breaking up east of a Billings to a Jordan line,
temperatures have responded with readings in the upper 70s to
lower 80s.

The big question is where thunderstorms will go over the next
several hours. The HRRR, which seems to be realistic, suggests
activity to develop over the central CWA about 300 pm while the
activity east of Livingston moves into the sw zones at about 5
pm. Activity should begin to wind down about 9 pm.

Upper low partially driving this, over oregon will drift into
southern alberta Sunday. Dry airmass will move into eastern
Montana will keep things somewhat dry but instability will bring
a slight chance of showers. A cooler day is expected with highs in
the 60s west to mid 70s east. A lake wind advisory is possible.

The intense upper low drifts into southern sask Monday. Winds
will be stronger and thus could be a bit choppy on Fort Peck
Lake. It will be cooler with highs mainly in the 60s. Best chance
for showers are over the nw zones. TFJ


.LONG TERM...Mon night through Sat...
The inherited long range forecast appears in fine working order
depicting an upper trough across the region helping to maintain
unsettled weather conditions. Given model spread, it is difficult
to pinpoint precise time periods or amounts to focus on.
Therefore, will leave broad-brush of slight chance to chance pops
throughout the period. Winds are also updated to reflect more
recent guidance. Maliawco

Previous long term discussion...

Synoptic Setup... long range begins with a large ridge running
from the southern Plains into the Great Lakes and up into Quebec.
A large Trough runs from off the coast of California through
western Montana and into northern Manitoba where it dips into a
much cooler arctic core. Southwest flow resides between these two
large airmasses dragging pacific moisture across northeast
Montana. A second synoptic trough/low is attempting to form over
the Gulf of Alaska.

Monday night onward... Long range has a very similar pattern
throughout with a southwest to zonal flow across eastern Montana
on a regular basis. The Pacific moisture feed during this time
means that PoPs will be higher than the climatic average.
However, mesoscale details are being washed out with slight
differences among multiple models. While a general active/wet
pattern is anticipated there are no key features or boundaries
that can at this time maintain focus from model-to-model or even
run-to-run. Therefore, a broad brush of 20 to 40 PoP occurred in
many periods. GAH


&&

.AVIATION...

Synopsis: Upper level disturbance will move across Montana
this afternoon and evening with scattered showers and
thunderstorms. Outside of any thunderstorms that occur VFR
conditions will prevail.

SEVERE STORMS POSSIBLE: By around 21Z showers and thunderstorms
will start to form with a handful becoming severe. Severe
potential should last through 06Z before storms either diminish
or move northeast out of the terminals.

Winds: Southeast at 15 to 25 kts...switching to the southwest around
06Z. Winds will be gusty and erratic near thunderstorms.

AEH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 9 PM MDT this evening For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow





000
FXUS65 KGGW 212055 CCA
AFDGGW

Area Forecast Discussion...CORRECTED
National Weather Service GLASGOW MT
255 PM MDT SAT MAY 21 2016

.SHORT TERM...for northeast Montana...tonight through Mon...
...Severe thunderstorms remain possible late this afternoon and
evening with large hail and damaging winds...

Are of thunderstorms have begun this afternoon. At 2pm, extend
entend from Stanford in central montana south to east of
Livingston. Much of this area is moving northeast and should
begin affecting the western zones later this afternoon. With
cloudcover breaking up east of a Billings to a Jordan line,
temperatures have responded with readings in the upper 70s to
lower 80s.

The big question is where thunderstorms will go over the next
several hours. The HRRR, which seems to be realistic, suggests
activity to develop over the central CWA about 300 pm while the
activity east of Livingston moves into the sw zones at about 5
pm. Activity should begin to wind down about 9 pm.

Upper low partially driving this, over oregon will drift into
southern alberta Sunday. Dry airmass will move into eastern
Montana will keep things somewhat dry but instability will bring
a slight chance of showers. A cooler day is expected with highs in
the 60s west to mid 70s east. A lake wind advisory is possible.

The intense upper low drifts into southern sask Monday. Winds
will be stronger and thus could be a bit choppy on Fort Peck
Lake. It will be cooler with highs mainly in the 60s. Best chance
for showers are over the nw zones. TFJ

.LONG TERM...Mon night through Sat...
The inherited long range forecast appears in fine working order
depicting an upper trough across the region helping to maintain
unsettled weather conditions. Given model spread, it is difficult
to pinpoint precise time periods or amounts to focus on.
Therefore, will leave broad-brush of slight chance to chance pops
throughout the period. Winds are also updated to reflect more
recent guidance. Maliawco

Previous long term discussion...

Synoptic Setup... long range begins with a large ridge running
from the southern Plains into the Great Lakes and up into Quebec.
A large Trough runs from off the coast of California through
western Montana and into northern Manitoba where it dips into a
much cooler arctic core. Southwest flow resides between these two
large airmasses dragging pacific moisture across northeast
Montana. A second synoptic trough/low is attempting to form over
the Gulf of Alaska.

Monday night onward... Long range has a very similar pattern
throughout with a southwest to zonal flow across eastern Montana
on a regular basis. The Pacific moisture feed during this time
means that PoPs will be higher than the climatic average.
However, mesoscale details are being washed out with slight
differences among multiple models. While a general active/wet
pattern is anticipated there are no key features or boundaries
that can at this time maintain focus from model-to-model or even
run-to-run. Therefore, a broad brush of 20 to 40 PoP occurred in
many periods. GAH


&&

.AVIATION...

Synopsis: Upper level disturbance will move across Montana
this afternoon and evening with scattered showers and
thunderstorms. Outside of any thunderstorms that occur VFR
conditions will prevail.

SEVERE STORMS POSSIBLE: By around 21Z showers and thunderstorms
will start to form with a handful becoming severe. Severe
potential should last through 06Z before storms either diminish
or move northeast out of the terminals.

Winds: Southeast at 15 to 25 kts...switching to the southwest around
06Z. Winds will be gusty and erratic near thunderstorms.

AEH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 9 PM MDT this evening For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow





000
FXUS65 KGGW 212047
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
247 PM MDT SAT MAY 21 2016

.SHORT TERM...for northeast Montana...tonight through Mon...
...Severe thunderstorms remain possible late this afternoon and
evening with large hail and damaging winds...

Are of thunderstorms have begun this afternoon. At 2pm, extend
entend from stanford in central montana south to east of
livingston. Much of this area is moving northeast and should
begin affecting the western zones later this afternoon. With
cloudcover breaking up east of a billings to a jordan line,
temperatures have responded with readings in the upper 70s to
lower 80s.

The big question is where thunderstorms will go over the next
several hours. The hrrr, which can be a bit more intense than
reality, suggests activity to develop over the central cwa about
300 pm while the activity east of livingston moves into the sw
zones at about 5 pm. Activity should begin to wind down about 9
pm.

Upper low partially driving this over oregon will drift into
southern alberta sunday. Dry airmass will move into eastern
montana will keep thigs somewhat dry but instability will bring a
slight chance of showers. A cooler day is expected with highs in
the 60s west to mid 70s east. A lake wind advisory is possible.

The intense upper low drifts into southern sask sunday. Winds
will be stronger and thus could be a bit choppy on fort peck lake.
It will be cooler with highs mainly in the 60s. Best chance for
showers are over the nw zones. TFJ

.LONG TERM...Mon night through Sat...
The inherited long range forecast appears in fine working order
depicting an upper trough across the region helping to maintain
unsettled weather conditions. Given model spread, it is difficult
to pinpoint precise time periods or amounts to focus on.
Therefore, will leave broad-brush of slight chance to chance pops
throughout the period. Winds are also updated to reflect more
recent guidance. Maliawco

Previous long term discussion...

Synoptic Setup... long range begins with a large ridge running
from the southern Plains into the Great Lakes and up into Quebec.
A large Trough runs from off the coast of California through
western Montana and into northern Manitoba where it dips into a
much cooler arctic core. Southwest flow resides between these two
large airmasses dragging pacific moisture across northeast
Montana. A second synoptic trough/low is attempting to form over
the Gulf of Alaska.

Monday night onward... Long range has a very similar pattern
throughout with a southwest to zonal flow across eastern Montana
on a regular basis. The Pacific moisture feed during this time
means that PoPs will be higher than the climatic average.
However, mesoscale details are being washed out with slight
differences among multiple models. While a general active/wet
pattern is anticipated there are no key features or boundaries
that can at this time maintain focus from model-to-model or even
run-to-run. Therefore, a broad brush of 20 to 40 PoP occured in
many periods. GAH


&&

.AVIATION...

Synopsis: Upper level disturbance will move across Montana
this afternoon and evening with scattered showers and
thunderstorms. Outside of any thunderstorms that occur VFR
conditions will prevail.

SEVERE STORMS POSSIBLE: By around 21Z showers and thunderstorms
will start to form with a handful becoming severe. Severe
potential should last through 06Z before storms either diminish
or move northeast out of the terminals.

Winds: Southeast at 15 to 25 kts...switching to the southwest around
06Z. Winds will be gusty and erratic near thunderstorms.

AEH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 9 PM MDT this evening For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow





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