The usual caveat applies. Knock these down probably by at least a quarter to a third for a more realistic forecast:
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Severe Jan 8-11 2024 System Severe
- Thread starter SD
- Start date
The usual caveat applies. Knock these down probably by at least a quarter to a third for a more realistic forecast:
BHS1975
Member
HRRR seems to be the most accurate by looking at the past events.
Sent from my iPhone using Tapatalk
tractor girl
Member
For folks in Athens/Atlanta area:
Latest SPC disc
Wind advisory and flood watch here. Man I love winter time
Windergawx
Member
and winter loves you!
Ron Burgundy
Member
Thanks!
FFC has Atlanta gusting to 35mph. I’ll take the over on that. Wouldn’t be surprised to see a couple around 50
HugeSnowStick
Member
As always, conservative. It has been gusting to 30 already today???
Statmospheric
Member
The 18z HRRR did step up the winds a good bit for many in NC, with 45-55 mph gusts across the piedmont and some isolated 60 mph+ maxes
Broken024
Member
Laying down the puddles for your trace of snow to land in
Nam looking more impressive then any run so far 60 degree dews making it to GSO 
Heres what I got on the HRRR
Gonna be fun working outside at Camp Lejeune tomorrow. I was working on base during the April 2011 outbreak too with me seeing a tornado driving home to GSO near Beaulaville on I-40 that day. Fun times.
Stormsfury
Member
progressing more aggressively..
severestorm
Member
RAH seems kind of meh. I mean, they talk about wind gusts in to the 40s and a conditional risk of stronger gusts with the squall line later, but their language doesn't seem all that concerning for stronger background gusts.
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 400 PM Monday...
There has been little change in overall forecast rationale for this
period, though with continued uncertainties surrounding to what
degree the boundary layer can destabilize and support conditional
probabilities of risks for both pre-frontal gradient wind and severe
convection.
A progressive mid/upper-level cyclone, now crossing the TX/OK
panhandles, will have reached swrn MO by the start of the period,
then continue to deepen while migrating newd to the lwr Great Lakes
by 12Z Wed. An initially positive tilt shortwave trough trailing the
cyclone will assume neutral to slight negative tilt while pivoting
from the lwr MS Valley to the srn Middle Atlantic coast. Strong
dynamics and kinematics will precede the cyclone and contribute to
both strong forcing for ascent and extreme shear over the Carolinas,
particularly during the afternoon and evening.
At the surface, a parent cyclone will deepen and occlude as it
follows migrates across the Great Lakes, following a similar path as
the deeper-layer cyclone. Meanwhile, a secondary frontal wave
initially invof srn AL, near a quadruple point of both a wedge front
along the periphery of the retreating in-situ CAD regime, and a
maritime warm front that will spread from the nrn GOM and South
Atlantic coastal region inland across srn through ern GA and the ern
Carolinas, will deepen while tracking over nrn GA and the Carolina
and srn Middle Atlantic Piedmont through Tue evening, then across
the coastal Middle Atlantic and srn New England Tue night.
Periods of rain and drizzle, amid CAD and surface stability early
Tue, will become increasingly heavy and convective, as the wedge
front rapidly retreats nwwd, immediately preceding the quadruple
point across the Carolinas through Tue evening. Despite the
associated strong low-level theta-e advection ahead of this wave,
with surface temperatures and dewpoints likely to increase into the
upr 50s/lwr 60s on average, generally weak lapse rates from the
surface through the mid-levels continue to lend uncertainty
regarding the degree of gradient wind gust potential and high-shear
low-CAPE severe weather risk in cntl NC. Further concerns center
around how quickly upstream convection will move ewd, probably in an
initially weakening state as it encounters the aforementioned
lingering stability over cntl NC, which would further subdue warm
sector destabilization prior to when the otherwise richest theta-e
air/near surface destabilization would arrive ahead of the secondary
frontal wave.
There remains the potential for sufficient boundary layer mixing
ahead of the secondary wave that would allow for surface wind gusts
of 30-40 kts, locally higher to materialize during the late
afternoon through evening, especially over the srn
Piedmont/Sandhills/srn-cntl Coastal Plain. A QLCS and line-embedded
mesovortices will then pose the greatest threat of heavy rain and a
conditional risk of damaging surface wind gusts/isolated tornadoes
as it moves across cntl NC most likely from mid-afternoon through
mid-evening. There also remains some, lesser potential for discrete
mini supercell development preceding the QLCS and across the ern
Carolinas during that time.
Showers/isolated storms will end from west to east overnight Tue,
with storm total rainfall likely to range from 1.5 - 3", highest
over the Piedmont, and the majority of which will fall within
convection Tue afternoon-evening. Urban and poor drainage flooding
may result, and a Flood Watch has been issued for the Piedmont and
wrn Sandhills, in the overlapping footprint of both the highest
predicted rain and lowest Flash Flood Guidance values. A secondary
surge of swly winds and gusts into the 30s kts will likely follow in
CAA and pressure rises overnight; and an extension of the Wind
Advisory should be strongly considered as timing gets to within the
1st to 2nd period issuance time. That CAA will also cause
temperatures to cool mostly into the 40s, except some upr 30s
possible over the wrn Piedmont, by Wed morning.
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 400 PM Monday...
There has been little change in overall forecast rationale for this
period, though with continued uncertainties surrounding to what
degree the boundary layer can destabilize and support conditional
probabilities of risks for both pre-frontal gradient wind and severe
convection.
A progressive mid/upper-level cyclone, now crossing the TX/OK
panhandles, will have reached swrn MO by the start of the period,
then continue to deepen while migrating newd to the lwr Great Lakes
by 12Z Wed. An initially positive tilt shortwave trough trailing the
cyclone will assume neutral to slight negative tilt while pivoting
from the lwr MS Valley to the srn Middle Atlantic coast. Strong
dynamics and kinematics will precede the cyclone and contribute to
both strong forcing for ascent and extreme shear over the Carolinas,
particularly during the afternoon and evening.
At the surface, a parent cyclone will deepen and occlude as it
follows migrates across the Great Lakes, following a similar path as
the deeper-layer cyclone. Meanwhile, a secondary frontal wave
initially invof srn AL, near a quadruple point of both a wedge front
along the periphery of the retreating in-situ CAD regime, and a
maritime warm front that will spread from the nrn GOM and South
Atlantic coastal region inland across srn through ern GA and the ern
Carolinas, will deepen while tracking over nrn GA and the Carolina
and srn Middle Atlantic Piedmont through Tue evening, then across
the coastal Middle Atlantic and srn New England Tue night.
Periods of rain and drizzle, amid CAD and surface stability early
Tue, will become increasingly heavy and convective, as the wedge
front rapidly retreats nwwd, immediately preceding the quadruple
point across the Carolinas through Tue evening. Despite the
associated strong low-level theta-e advection ahead of this wave,
with surface temperatures and dewpoints likely to increase into the
upr 50s/lwr 60s on average, generally weak lapse rates from the
surface through the mid-levels continue to lend uncertainty
regarding the degree of gradient wind gust potential and high-shear
low-CAPE severe weather risk in cntl NC. Further concerns center
around how quickly upstream convection will move ewd, probably in an
initially weakening state as it encounters the aforementioned
lingering stability over cntl NC, which would further subdue warm
sector destabilization prior to when the otherwise richest theta-e
air/near surface destabilization would arrive ahead of the secondary
frontal wave.
There remains the potential for sufficient boundary layer mixing
ahead of the secondary wave that would allow for surface wind gusts
of 30-40 kts, locally higher to materialize during the late
afternoon through evening, especially over the srn
Piedmont/Sandhills/srn-cntl Coastal Plain. A QLCS and line-embedded
mesovortices will then pose the greatest threat of heavy rain and a
conditional risk of damaging surface wind gusts/isolated tornadoes
as it moves across cntl NC most likely from mid-afternoon through
mid-evening. There also remains some, lesser potential for discrete
mini supercell development preceding the QLCS and across the ern
Carolinas during that time.
Showers/isolated storms will end from west to east overnight Tue,
with storm total rainfall likely to range from 1.5 - 3", highest
over the Piedmont, and the majority of which will fall within
convection Tue afternoon-evening. Urban and poor drainage flooding
may result, and a Flood Watch has been issued for the Piedmont and
wrn Sandhills, in the overlapping footprint of both the highest
predicted rain and lowest Flash Flood Guidance values. A secondary
surge of swly winds and gusts into the 30s kts will likely follow in
CAA and pressure rises overnight; and an extension of the Wind
Advisory should be strongly considered as timing gets to within the
1st to 2nd period issuance time. That CAA will also cause
temperatures to cool mostly into the 40s, except some upr 30s
possible over the wrn Piedmont, by Wed morning.
tractor girl
Member
Peachtree NWS update:
Severe Threat:
Very impressive parameter space looks to set up over the CWA during
the early morning hours and into the afternoon on Tuesday. Strong
WAA overnight will allow for two not so great things - the first, it
will keep the boundary layer well mixed, likely preventing any
nocturnal inversion from setting up, and second, will likely help
break down our CAD/wedge in place. Normally I would say the wedge
will win out, but with a 80+ kt jet at 850mb overspreading the
region, that will aid greatly in mixing it out. That being said, the
best winds in that won`t arrive until the morning hours as the line
begins pushing through, so it may take a bit of time for the warm
sector to lift through the CWA. The current SPC outlook reflects
this nicely, showing biggest risks from Columbus to Macon and then
pushing north.
The wind threat will likely be the biggest risk right out. With the
very strong kinematics, mixing down big winds in the strongest
storms won`t take much in the way of instability. QLCS tornadoes
will likely be in play, especially given fish hook look to the
hodographs which give tremendous SRH values of 200-400 m2/s2. The
big question mark is the instability. This has potential to be a
classic HSLC event, but the ability to be fully surface based will
likely be dependent on how quickly and how strong the WAA occurs.
This creates uncertainty in the northern extent, and certainly won`t
rule out seeing some severe weather as far north as the metro if
WAA really gets moving.
Severe Threat:
Very impressive parameter space looks to set up over the CWA during
the early morning hours and into the afternoon on Tuesday. Strong
WAA overnight will allow for two not so great things - the first, it
will keep the boundary layer well mixed, likely preventing any
nocturnal inversion from setting up, and second, will likely help
break down our CAD/wedge in place. Normally I would say the wedge
will win out, but with a 80+ kt jet at 850mb overspreading the
region, that will aid greatly in mixing it out. That being said, the
best winds in that won`t arrive until the morning hours as the line
begins pushing through, so it may take a bit of time for the warm
sector to lift through the CWA. The current SPC outlook reflects
this nicely, showing biggest risks from Columbus to Macon and then
pushing north.
The wind threat will likely be the biggest risk right out. With the
very strong kinematics, mixing down big winds in the strongest
storms won`t take much in the way of instability. QLCS tornadoes
will likely be in play, especially given fish hook look to the
hodographs which give tremendous SRH values of 200-400 m2/s2. The
big question mark is the instability. This has potential to be a
classic HSLC event, but the ability to be fully surface based will
likely be dependent on how quickly and how strong the WAA occurs.
This creates uncertainty in the northern extent, and certainly won`t
rule out seeing some severe weather as far north as the metro if
WAA really gets moving.