SPC - No watches are valid as of Fri Dec 8 07:01:02 UTC 2023

No watches are valid as of Fri Dec  8 07:01:02 UTC 2023.

SPC - No MDs are in effect as of Fri Dec 8 07:01:02 UTC 2023

No Mesoscale Discussions are in effect as of Fri Dec  8 07:01:02 UTC 2023.

SPC Dec 8, 2023 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
      
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1152 PM CST Thu Dec 07 2023

Valid 081200Z - 091200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE ARK-LA-TEX AND OZARKS...

...SUMMARY...
Thunderstorms associated with isolated large hail will be possible
from late afternoon into tonight across parts of the Ark-La-Tex and
Ozarks.

...Ark-La-Tex/Ozarks...
A mid-level jet and an associated upper-level trough will dig
southeastward into the central Rockies today. The trough will move
into the central Plains and southern Rockies tonight. Ahead of the
system, a moist airmass will advect northward today across east
Texas and the Ark-La-Tex. In response to lift associated with a 40
to 50 knot low-level jet, elevated thunderstorms may initiate and
develop as the upper-level trough approaches. The corridor with the
greatest potential for convective development should be from  east
Texas northward across Arkansas and into Missouri. Along the
southern part of this corridor, RAP forecast soundings this evening
generally increase MUCAPE into the 1000 to 1200 J/kg range, mainly
in northeast Texas and parts of Arkansas. This, combined with 40
knot of effective shear and 700-500 mb lapse rates near 7.5 C/km,
may support an isolated large-hail threat. Any severe threat could
be sustained during the overnight period as large-scale ascent moves
into the region ahead of the approaching trough. However, most CAM
solutions have trouble initiating storms suggesting convective
coverage will be very isolated, making any potential for hail
conditional.

..Broyles.. 12/08/2023


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SPC Dec 8, 2023 0700 UTC Day 2 Convective Outlook

SPC 0700Z Day 2 Outlook
      
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1256 AM CST Fri Dec 08 2023

Valid 091200Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST TX TO
THE TN VALLEY...

...SUMMARY...
Scattered severe thunderstorms with tornadoes, damaging winds, and
large hail will be possible from east Texas to the Tennessee Valley,
mainly Saturday afternoon and evening.

...Synopsis...
A leading cyclogenetic surface low will quickly move from the Lake
MI area at 12Z Saturday towards James Bay. As this occurs, the cold
front trailing to its south-southwest will initially decelerate over
the south-central states, downstream of a basal shortwave impulse.
This feature should advance from the NM vicinity to the Ark-La-Tex
by 12Z Sunday. Much weaker secondary cyclogenesis is anticipated
ahead of this latter wave from the Ark-La-Tex to the TN Valley. 

...East TX to the TN Valley...
While regional/global guidance has converged towards a consensus on
the upper-level synoptic pattern, differences emerge in
timing/placement of the surface baroclinic zone. In addition, CAM
guidance offers quite a bit of spread with the potential convective
evolution on Saturday. As a result, primary change has been to
expand the northeast extent of severe probabilities within a
conditionally favorable, high-shear/low-CAPE environment.

From east TX into south AR and west MS, a plume of moderate buoyancy
characterized by MLCAPE of 1000-2000 J/kg will become established as
surface temperatures rise into the 70s, amid dew points from the mid
to upper 60s. Increasing mid-level height falls will overspread the
aforementioned baroclinic zone midday, with convective development
along/north of the surface front initially probable near the weak
cyclone in the Ark-La-Tex. This should become more widespread to the
east and south during the afternoon, although spread in CAM guidance
is above average with just how quickly this actually occurs and the
southward extent of convective development in east TX/west LA during
the afternoon. Despite these differences, strong southwesterly
deep-layer shear will be favorable for supercells producing large
hail, especially where flow can be semi-orthogonal to the front
across east TX and the Sabine Valley. A clustered convective mode
should dominate to the east across the Mid-South owing to
orientation of convective development near/ahead of the cold front
more closely paralleling the deep-layer shear vector. But embedded
supercells are expected as well, with low-level hodographs
adequately enlarged for a few tornadoes. 

By late afternoon to early evening, an extensive swath of clusters
and line segments should dominate. Some increase in low-level SRH is
anticipated during this time frame, focused on central to north
portions of MS/AL and northward. This should foster a continued
damaging-wind and embedded tornado threat east of the MS Valley even
as convection outpaces/overturns the instability plume.
Low-probability wind/tornado threats will probably persist overnight
but should gradually wane in time.

..Grams.. 12/08/2023


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SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
          
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1153 PM CST Thu Dec 07 2023

Valid 081200Z - 091200Z

...Synopsis...
An upper-level trough will be in the process of intensifying and
digging southeastward today. A surface low will deepen in western
Oklahoma during the morning and into the afternoon. Ahead of a cold
front, westerly surface winds will intensify from the South Plains
into the Trans Pecos. Winds of 15-20 mph (locally to 25 mph) and RH
of 15-20% will develop in this downslope regime. Given  at least
marginally dry fuels, elevated to locally critical fire weather is
possible.

Behind the upper trough, surface high pressure will increase within
the Great Basin. Offshore flow will increase across southern
California. Winds will be on the increase late tonight into Saturday
morning. It is not certain how low RH will fall, but a couple hours
of locally elevated fire weather are possible late tonight.

..Wendt.. 12/08/2023

...Please see www.spc.noaa.gov/fire for graphic product...


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SPC Day 2 Fire Weather Outlook

SPC Day 2 Fire Weather Outlook
          
Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1154 PM CST Thu Dec 07 2023

Valid 091200Z - 101200Z

...Synopsis...
The upper-level trough will move through the southern Plains and
towards the lower Mississippi Valley, amplifying as it progresses.
At the surface, a cold front will continue to the east through the
Plains. Dry, gusty conditions are likely for at least parts of the
southern High Plains into the Rio Grande Valley. RH may end up more
marginal on Saturday compared to Friday due to the cold advection.
Values near 20% appear possible for the Trans-Pecos into the
adjacent Rio Grande Valley. Winds of 15-20 mph (with higher gusts)
are probable as well. Fine fuels are expected to be marginally dry
and support an elevated fire weather threat.

Offshore winds in southern California will likely peak Saturday
morning. Moderately strong winds could continue through much of the
day, particularly in the wind-prone areas. RH could fall as low as
10-15% in some areas with 15-20% being more common. Recent fuel
guidance continues to suggest unreceptive fuels, especially within
the higher elevations. Drier fine fuels are possible in the
valleys/plains. Despite elevated to critical meteorological
conditions, fuels should generally mitigate most concerns. Locally
elevated conditions are still possible for several hours.

..Wendt.. 12/08/2023

...Please see www.spc.noaa.gov/fire for graphic product...


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