2 weeks 2 days ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1233 AM CDT Fri Sep 12 2025
Valid 121200Z - 131200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
MONTANA INTO THE DAKOTAS AND ACROSS THE FOUR CORNERS REGION...
...SUMMARY...
A few storms capable of isolated severe wind gusts are possible
across the Four Corners region, and from eastern Montana into the
Dakotas.
...Synopsis...
An upper trough will remain over the Intermountain West, making slow
eastward progress through the period. An upper disturbance is
forecast to move from CO into the Dakotas late in the day, while a
strong midlevel jet rounds the base of the trough across AZ
overnight. Gradual height falls will occur across the length of High
Plains primary overnight as the Plains upper ridge gradually
weakens.
At the surface, a weak area of low pressure is forecast over SD,
with a trough extending westward across WY and into the Great Basin
during the afternoon with strong heating. Dewpoints in the 60s F
will be common across the mid MO Valley, especially from MN into the
Dakotas where surface winds will be backed north of the low. Rather
veered/southwesterly 850 mb flow is forecast overnight, with only
pockets of positive theta-e advection.
...Eastern MT into the Dakotas...
Moderate instability will develop over much of the northern Plains,
but beneath temporary upper ridging. Storms are most likely to form
over eastern MT and WY, beneath cooler temperatures aloft and where
less capping will exist. Isolated hail may occur with these widely
scattered afternoon cells. Later in the evening, a few cells may
persist into the western Dakotas with hail potential, and there
appears to be a possibility of scattered damaging gusts as
activity/outflow moves out of WY/CO and interacts with stronger
instability over the Dakotas overnight. Given the lack of low-level
jet support and uncertainty, will maintain 5% probabilities.
...Four Corners Region...
Daytime heating combined with a midlevel moist plume and cooling
aloft should yield scattered afternoon development over far eastern
AZ and UT into western CO and NM. Instability will not be
particularly strong, but likely sufficient for a few damaging gusts
or marginal hail as the most prevalent storm mode is expected to be
cellular with favorably long hodographs/veering with height. Some of
this activity may persist well into the evening over NM.
..Jewell/Squitieri.. 09/12/2025
Read more2 weeks 2 days ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1233 AM CDT Fri Sep 12 2025
Valid 121200Z - 131200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
MONTANA INTO THE DAKOTAS AND ACROSS THE FOUR CORNERS REGION...
...SUMMARY...
A few storms capable of isolated severe wind gusts are possible
across the Four Corners region, and from eastern Montana into the
Dakotas.
...Synopsis...
An upper trough will remain over the Intermountain West, making slow
eastward progress through the period. An upper disturbance is
forecast to move from CO into the Dakotas late in the day, while a
strong midlevel jet rounds the base of the trough across AZ
overnight. Gradual height falls will occur across the length of High
Plains primary overnight as the Plains upper ridge gradually
weakens.
At the surface, a weak area of low pressure is forecast over SD,
with a trough extending westward across WY and into the Great Basin
during the afternoon with strong heating. Dewpoints in the 60s F
will be common across the mid MO Valley, especially from MN into the
Dakotas where surface winds will be backed north of the low. Rather
veered/southwesterly 850 mb flow is forecast overnight, with only
pockets of positive theta-e advection.
...Eastern MT into the Dakotas...
Moderate instability will develop over much of the northern Plains,
but beneath temporary upper ridging. Storms are most likely to form
over eastern MT and WY, beneath cooler temperatures aloft and where
less capping will exist. Isolated hail may occur with these widely
scattered afternoon cells. Later in the evening, a few cells may
persist into the western Dakotas with hail potential, and there
appears to be a possibility of scattered damaging gusts as
activity/outflow moves out of WY/CO and interacts with stronger
instability over the Dakotas overnight. Given the lack of low-level
jet support and uncertainty, will maintain 5% probabilities.
...Four Corners Region...
Daytime heating combined with a midlevel moist plume and cooling
aloft should yield scattered afternoon development over far eastern
AZ and UT into western CO and NM. Instability will not be
particularly strong, but likely sufficient for a few damaging gusts
or marginal hail as the most prevalent storm mode is expected to be
cellular with favorably long hodographs/veering with height. Some of
this activity may persist well into the evening over NM.
..Jewell/Squitieri.. 09/12/2025
Read more2 weeks 2 days ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1233 AM CDT Fri Sep 12 2025
Valid 121200Z - 131200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
MONTANA INTO THE DAKOTAS AND ACROSS THE FOUR CORNERS REGION...
...SUMMARY...
A few storms capable of isolated severe wind gusts are possible
across the Four Corners region, and from eastern Montana into the
Dakotas.
...Synopsis...
An upper trough will remain over the Intermountain West, making slow
eastward progress through the period. An upper disturbance is
forecast to move from CO into the Dakotas late in the day, while a
strong midlevel jet rounds the base of the trough across AZ
overnight. Gradual height falls will occur across the length of High
Plains primary overnight as the Plains upper ridge gradually
weakens.
At the surface, a weak area of low pressure is forecast over SD,
with a trough extending westward across WY and into the Great Basin
during the afternoon with strong heating. Dewpoints in the 60s F
will be common across the mid MO Valley, especially from MN into the
Dakotas where surface winds will be backed north of the low. Rather
veered/southwesterly 850 mb flow is forecast overnight, with only
pockets of positive theta-e advection.
...Eastern MT into the Dakotas...
Moderate instability will develop over much of the northern Plains,
but beneath temporary upper ridging. Storms are most likely to form
over eastern MT and WY, beneath cooler temperatures aloft and where
less capping will exist. Isolated hail may occur with these widely
scattered afternoon cells. Later in the evening, a few cells may
persist into the western Dakotas with hail potential, and there
appears to be a possibility of scattered damaging gusts as
activity/outflow moves out of WY/CO and interacts with stronger
instability over the Dakotas overnight. Given the lack of low-level
jet support and uncertainty, will maintain 5% probabilities.
...Four Corners Region...
Daytime heating combined with a midlevel moist plume and cooling
aloft should yield scattered afternoon development over far eastern
AZ and UT into western CO and NM. Instability will not be
particularly strong, but likely sufficient for a few damaging gusts
or marginal hail as the most prevalent storm mode is expected to be
cellular with favorably long hodographs/veering with height. Some of
this activity may persist well into the evening over NM.
..Jewell/Squitieri.. 09/12/2025
Read more2 weeks 2 days ago
MD 2061 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN NORTH DAKOTA
Mesoscale Discussion 2061
NWS Storm Prediction Center Norman OK
1011 PM CDT Thu Sep 11 2025
Areas affected...portions of northern North Dakota
Concerning...Severe potential...Watch unlikely
Valid 120311Z - 120515Z
Probability of Watch Issuance...5 percent
SUMMARY...A few more instances of severe hail may occur over the
next few hours with any discrete supercells that form or persist.
DISCUSSION...Isolated, splitting supercells have developed along or
immediately north of a quasi-stationary baroclinic boundary, and
have produced severe hail over the past hour. These storms are
likely elevated amid an environment where MLCINH continues to
increase. When also considering weak forcing for ascent, questions
remain if additional storms will form, and if the ongoing supercells
will persist. Nonetheless, 2000-3000 J/kg MLCAPE and 35+ kts of
effective bulk shear will continue to support the potential for
severe-hail-producing supercells for at least a couple more hours.
..Squitieri/Hart.. 09/12/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...BIS...
LAT...LON 48560388 48830146 48709934 48309801 47859763 47459812
47359937 47390090 47580233 47900329 48080348 48560388
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
Read more2 weeks 2 days ago
Issued at 900 PM CST Thu Sep 11 2025 000
WTPZ43 KNHC 120245
TCDEP3
Tropical Depression Thirteen-E Discussion Number 2
NWS National Hurricane Center Miami FL EP132025
900 PM CST Thu Sep 11 2025
The satellite appearance of Thirteen-E has improved some since the
previous advisory, with deep convection continuing to burst over or
near the estimated low-level center. The latest subjective Dvorak
current intensity estimates from TAFB and SAB were 2.5/35 kt and
2.0/30 kt. Meanwhile the objective estimates from UW-CIMSS have
ranged from 28 to 35 kt since the previous advisory. Based on a
blend of these data, the initial intensity has been held, perhaps
conservatively, at 30 kt for this advisory package.
The depression is moving to the west-northwest, or 290 degrees, at
10 kt. This general motion is expected to continue for the next
couple days, as the cyclone is steered by a mid-level ridge over
northern Mexico and Texas. A turn toward the northwest along with a
decrease in forward speed is expected over the weekend, as the
system moves along the southwestern periphery of the mid-level
ridge, with that motion continuing through day 5. The official
track forecast lies is very close to the previous advisory, roughly
between the corrected consensus HCCA and AI-Driven GDMI track aids.
The circulation of Thirteen-E remains very small, with an estimated
radius of the outermost closed isobar only 80 n mi, and this may be
generous. In the next couple of days, the global models suggest
that moderate northeasterly vertical wind shear, along with the
proximity to land, should limit the system's ability to intensify
significantly, and the intensity forecast only calls for some slow
strengthening. Over the weekend, environmental conditions should
become more favorable for intensification, as the system will be
farther offshore, over very warm water and surrounded by moist
mid-level air, while vertical wind shear will drop off to light
levels and become aligned with the motion of the cyclone. This
should lead to steady strengthening, with the system forecast to
become a hurricane by 72 hours. By day 5, cooler sea surface
temperatures and drier more stable environment should lead to a
weakening trend. The official intensity forecast lies on the higher
end of the intensity guidance envelope and closest to the AI-Driven
GDMI intensity aid.
Key Messages:
1. Heavy rainfall associated with Tropical Depression Thirteen-E
will impact southern and southwestern Mexico through Sunday, which
could result in flash flooding, particularly in areas of higher
terrain.
2. The depression is forecast to become a tropical storm later
tonight, while moving parallel to the southern and southwestern
coasts of Mexico. While the strongest winds are expected to remain
offshore, gusty winds are possible along portions of the southern
and southwestern coast of Mexico from Punta Maldonado through
Manzanillo during the next day or so. Interests in these areas
should monitor the progress of this system.
FORECAST POSITIONS AND MAX WINDS
INIT 12/0300Z 16.0N 99.6W 30 KT 35 MPH
12H 12/1200Z 16.5N 101.3W 35 KT 40 MPH
24H 13/0000Z 17.1N 103.5W 40 KT 45 MPH
36H 13/1200Z 17.6N 105.5W 45 KT 50 MPH
48H 14/0000Z 18.0N 107.1W 50 KT 60 MPH
60H 14/1200Z 18.4N 108.6W 60 KT 70 MPH
72H 15/0000Z 18.9N 109.9W 70 KT 80 MPH
96H 16/0000Z 20.7N 112.6W 70 KT 80 MPH
120H 17/0000Z 23.0N 114.7W 55 KT 65 MPH
$$
Forecaster Jelsema (CPHC)
NHC Webmaster
2 weeks 2 days ago
Issued at 900 PM CST Thu Sep 11 2025 304
WTPZ33 KNHC 120244
TCPEP3
BULLETIN
Tropical Depression Thirteen-E Advisory Number 2
NWS National Hurricane Center Miami FL EP132025
900 PM CST Thu Sep 11 2025
...TROPICAL DEPRESSION THIRTEEN-E HEADING WEST-NORTHWESTWARD OFF THE
COAST OF SOUTHERN MEXICO...
SUMMARY OF 900 PM CST...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...16.0N 99.6W
ABOUT 65 MI...105 KM SSE OF ACAPULCO MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.
Interests along the coast of southwestern Mexico should monitor the
progress of this system.
DISCUSSION AND OUTLOOK
----------------------
At 900 PM CST (0300 UTC), the center of Tropical Depression
Thirteen-E was located near latitude 16.0 North, longitude 99.6
West. The depression is moving toward the west-northwest near 12 mph
(19 km/h), and this general motion is expected to continue during
the next couple of days. On the forecast track, the center of the
depression will move parallel to, but offshore of, the southwestern
coast of mainland Mexico.
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours. Slow
strengthening is expected during the next couple of days, and
Thirteen-E is forecast to become a Tropical Storm later tonight.
The estimated minimum central pressure is 1007 mb (29.74 inches).
HAZARDS AFFECTING LAND
----------------------
RAINFALL: Tropical Depression Thirteen-E will lead to rainfall
totals of 2 to 4 inches, with local amounts of 6 inches, across
southern and southwestern Mexico through Sunday. This brings a risk
of flash flooding, especially in areas of higher terrain.
For a complete depiction of forecast rainfall and flash flooding
associated with Thirteen-E, please see the National Weather Service
Storm Total Rainfall Graphic, available at
hurricanes.gov/graphics_ep3.shtml?rainqpf
WIND: Gusty winds are possible over portions of the southern coast
of Mexico from Punta Maldonado through Manzanillo during the next
day or so.
NEXT ADVISORY
-------------
Next complete advisory at 300 AM CST.
$$
Forecaster Jelsema (CPHC)
NHC Webmaster
2 weeks 2 days ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Thu Sep 11 2025
Valid 120100Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE NORTHERN ROCKIES AND PLAINS...
...SUMMARY...
A few widely spaced strong to severe storms remain possible from
western Colorado into eastern Montana and the western Dakotas.
Isolated hail or strong gusts are possible.
...Discussion...
Scattered thunderstorms persist this evening from the Canadian
border southward across the Rockies, beneath moderate southwest flow
aloft. 00Z soundings from GJT to GGW show moderately steep lapse
rates, with 500 to 1500 J/kg MUCAPE. Given little height falls
overnight, most of these storms should diminish after sunset.
Farther east across the northern High Plains, stronger instability
exists with MLCAPE of 1500-2500 J/kg from UNR to BIS. However,
minimal capping does exist. Conditionally, the environment supports
large hail, though there is little focusing mechanism for any
concentrated risk areas. As such, the Slight Risk has been removed,
due to expected isolated nature of the cells.
..Jewell.. 09/12/2025
Read more2 weeks 2 days ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Thu Sep 11 2025
Valid 120100Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE NORTHERN ROCKIES AND PLAINS...
...SUMMARY...
A few widely spaced strong to severe storms remain possible from
western Colorado into eastern Montana and the western Dakotas.
Isolated hail or strong gusts are possible.
...Discussion...
Scattered thunderstorms persist this evening from the Canadian
border southward across the Rockies, beneath moderate southwest flow
aloft. 00Z soundings from GJT to GGW show moderately steep lapse
rates, with 500 to 1500 J/kg MUCAPE. Given little height falls
overnight, most of these storms should diminish after sunset.
Farther east across the northern High Plains, stronger instability
exists with MLCAPE of 1500-2500 J/kg from UNR to BIS. However,
minimal capping does exist. Conditionally, the environment supports
large hail, though there is little focusing mechanism for any
concentrated risk areas. As such, the Slight Risk has been removed,
due to expected isolated nature of the cells.
..Jewell.. 09/12/2025
Read more2 weeks 2 days ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Thu Sep 11 2025
Valid 120100Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE NORTHERN ROCKIES AND PLAINS...
...SUMMARY...
A few widely spaced strong to severe storms remain possible from
western Colorado into eastern Montana and the western Dakotas.
Isolated hail or strong gusts are possible.
...Discussion...
Scattered thunderstorms persist this evening from the Canadian
border southward across the Rockies, beneath moderate southwest flow
aloft. 00Z soundings from GJT to GGW show moderately steep lapse
rates, with 500 to 1500 J/kg MUCAPE. Given little height falls
overnight, most of these storms should diminish after sunset.
Farther east across the northern High Plains, stronger instability
exists with MLCAPE of 1500-2500 J/kg from UNR to BIS. However,
minimal capping does exist. Conditionally, the environment supports
large hail, though there is little focusing mechanism for any
concentrated risk areas. As such, the Slight Risk has been removed,
due to expected isolated nature of the cells.
..Jewell.. 09/12/2025
Read more2 weeks 2 days ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Thu Sep 11 2025
Valid 120100Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE NORTHERN ROCKIES AND PLAINS...
...SUMMARY...
A few widely spaced strong to severe storms remain possible from
western Colorado into eastern Montana and the western Dakotas.
Isolated hail or strong gusts are possible.
...Discussion...
Scattered thunderstorms persist this evening from the Canadian
border southward across the Rockies, beneath moderate southwest flow
aloft. 00Z soundings from GJT to GGW show moderately steep lapse
rates, with 500 to 1500 J/kg MUCAPE. Given little height falls
overnight, most of these storms should diminish after sunset.
Farther east across the northern High Plains, stronger instability
exists with MLCAPE of 1500-2500 J/kg from UNR to BIS. However,
minimal capping does exist. Conditionally, the environment supports
large hail, though there is little focusing mechanism for any
concentrated risk areas. As such, the Slight Risk has been removed,
due to expected isolated nature of the cells.
..Jewell.. 09/12/2025
Read more2 weeks 2 days ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0448 PM CDT Thu Sep 11 2025
Valid 131200Z - 191200Z
...Day 3-5/Saturday-Monday...
A mid-level trough across the Intermountain West will pivot
northeastward into the Central and Northern Plains in the Day
3-4/Saturday-Sunday period, shifting the bulk of shower and
thunderstorm activity east of the Rockies. Higher forecast
confidence now exists in a positively tilted mid-level short wave
trough entering the Northwest on Day 4-5/Sunday-Monday after a brief
warm and dry day on Day 3/Saturday. Cooler temperatures behind an
associated cold front, influx of Pacific moisture and precipitation
will mitigate fire weather concerns for the Pacific Northwest
through Day 5/Monday. Meanwhile ridging across the Southern Plains
into the Midwest will support dry conditions and well above normal
temperatures through the weekend.
...Day 6-8/Tuesday-Thursday...
Ridging will quickly build over the Pacific Northwest along with the
development of a coastal thermal trough by Day 6/Tuesday. An
offshore pressure gradient will support a drier east/northeast flow
west of the Cascades on Tuesday. However, recent moisture and
expected preceding rainfall along and west of the Cascades on Day
4/Sunday should lower fire weather concerns overall in advance of
the potential offshore wind event. High pressure will continue to
promote above normal temperatures and mainly dry conditions across
much of the Midwest and lower Mississippi Valley through the Day
8/Thursday period, further drying fuels across the region.
..Williams.. 09/11/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
