-
DAY1SVR: Day 1 Convective
From
Dumas Walker@21:1/175 to
All on Sat Dec 28 17:12:00 2024
ACUS01 KWNS 281949
SWODY1
SPC AC 281947
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0147 PM CST Sat Dec 28 2024
Valid 282000Z - 291200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND TONIGHT ACROSS PORTIONS OF EAST TEXAS...LOUISIANA...CENTRAL AND
SOUTHERN MISSISSIPPI...AND SOUTHWESTERN ALABAMA...
...SUMMARY...
Tornadoes (some strong with at least EF2 damage possible), severe
gusts and hail are expected today into tonight. The threat area will
continue to shift eastward across east Texas and the lower
Mississippi Valley today, then over the Tennessee Valley, parts of
Georgia, and the central Gulf Coast tonight.
...20Z Update...
Severe probabilities have been adjusted in portions of central into
East Texas as well as portions of Arkansas/western Tennessee. These
areas have been impacted by earlier convection and further
destabilization does not appear likely. The remainder of the
outlook, the Moderate risk area in particular, is unchanged. The
corridor of greatest concern appears to be from portions of central
Louisiana into southwest Mississippi. Upper 60s to low 70s dewpoints
are in place and the potential for discrete/semi-discrete storms
should be maximized here later this afternoon/evening as the
mid-level jet moves overhead and the low-level jet strengthens.
..Wendt.. 12/28/2024
.PREV DISCUSSION... /ISSUED 1029 AM CST Sat Dec 28 2024/
...East TX to AL/GA...
A powerful mid-level shortwave trough and associated 80-90 knot jet
max will rotate quickly eastward across TX today and become
negatively-tilted as it tracks into the lower MS Valley this
evening. Ample low-level moisture (dewpoints in the mid 60s to
lower 70s) is in place ahead of this system across east TX, much of
LA, and central/southern MS. Morning convection is slowly weakening
across the warm sector, and low-clouds will continue to erode. This
will help to develop a corridor of moderate instability with MLCAPE
values of 1500-2000 J/kg. This will set the stage for a significant
severe weather event through the evening as supercells and bowing
structures form over east TX and race eastward across LA into MS.
The co-location of the mid-level jet, strengthening winds in the
low-levels, surface cyclogenesis, and ample moisture provide a synoptically-evident setup for all severe hazards through the
evening. The corridor of greatest concern will be late afternoon
through the evening from central LA into central MS. Considered an
upgrade to HIGH for this area, but will maintain the ongoing MDT
after consultation with local WFOs. Strong and long-tracked
tornadoes and widespread damaging winds are possible in this region,
with the primary uncertainty regarding storm-mode and linear forcing mechanisms.
Activity will spread across AL overnight, where slightly less
low-level moisture will somewhat decrease the overall severe threat.
Nevertheless, an active squall line with damaging wind potential
and embedded rotating storms/tornado threat will likely persist.
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Sat Feb 8 09:05:00 2025
ACUS01 KWNS 081245
SWODY1
SPC AC 081244
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0644 AM CST Sat Feb 08 2025
Valid 081300Z - 091200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated to scattered thunderstorm development is possible across
parts of the Ohio Valley today.
...Ohio Valley...
A low-amplitude shortwave trough currently extends from western ND southwestward through western/central WY. This shortwave is expected
to progress quickly eastward throughout the day, moving across the
Great Lakes and reaching the Northeast by early tomorrow. In
response, the surface low currently over central OK is forecast to
rapidly translate northeastward through the Mid MS and OH Valleys,
moving along the leading edge of low-level moisture advection.
Strengthening warm-air advection throughout the warm sector
preceding this low will help moisten the low- to mid-levels enough
to support limited buoyancy, particularly as mid-level temperatures
cool. Ascent attendant to the approaching shortwave trough will be
augmented by both persistent warm-air advection and more mesoscale
lift near the surface low. The resulting combination of lift and
buoyancy should support deeper convective structures capable of
lightning production. Most likely time frame for these deeper storms
is between 21Z to 04Z, with the highest coverage anticipated over
the Middle and Upper OH Valley.
Strengthening mid-level flow is also expected, with a belt of 100+
kt 500-mb winds spreading across the region after 21Z. This could
result in rotation and potentially some hail production within any
deeper, more persistent updrafts. However, the scant buoyancy is
expected to limit the number and duration of any deeper updrafts,
with the overall severe potential remaining low as a result.
..Mosier/Broyles.. 02/08/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Sun Feb 9 08:59:00 2025
ACUS01 KWNS 091250
SWODY1
SPC AC 091248
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0648 AM CST Sun Feb 09 2025
Valid 091300Z - 101200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A low risk for a few thunderstorms exists early in the period across
the Mid-South region.
...Synopsis...
Broadly cyclonic flow aloft, with several embedded shortwave
troughs, is expected across the northern CONUS today. Largely zonal
flow is anticipated across the southern CONUS, with negligible
height changes. Recent surface analysis shows an expansive area of
high pressure associated with a dry, continental airmass covering
much of the central and eastern CONUS. A weak frontal boundary is in
place from the TX Coastal Plains northeastward across the Southeast
States into NC, between the cooler and dry airmass to its north and
the modified Gulf airmass to its south. A slow southward progression
of this front is anticipated throughout the day, with this front
likely extending from southern GA westward along the Gulf Coast into
South TX by 12Z Monday.
...Arklatex into the Mid-South...
Modest warm-air advection across the frontal zone mentioned in the
synopsis is contributing to showers and isolated thunderstorms
across Arkansas this morning. 12Z LZK sounding sampled the airmass
supporting these showers and thunderstorms well, with a notable warm
nose contributing to scant elevated buoyancy above about 850 mb. The
warm-air advection is expected to persist over the region for at
least the next several hours, while it gradually shifts eastward and
weakens. This will support the potential for isolated thunderstorms
this morning from the Arklatex eastward into the Mid-South, with the
overall thunderstorm potential diminishing with eastern extent.
..Mosier/Broyles.. 02/09/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Mon Feb 10 09:13:00 2025
ACUS01 KWNS 101247
SWODY1
SPC AC 101245
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0645 AM CST Mon Feb 10 2025
Valid 101300Z - 111200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunderstorms are possible from central Texas across
southeast Oklahoma into western Arkansas tonight.
...TX/OK/AR...
Recent satellite imagery shows a well-defined shortwave trough off
the southern CA/Baja CA coast. This feature is forecast to progress
quickly east-northeastward throughout the day, traversing the Southwest/northern Mexico and reaching the southern Plains by
tomorrow morning. Airmass ahead of this feature across the southern
Plains is currently cool and dry, with the moist airmass still
offshore. Mass response ahead of the approaching shortwave will lead
to some modest airmass modification, with upper 50s/low 60s surface
dewpoints potentially reaching the TX Hill Country/central TX by
tomorrow morning. Even with these moistening low levels, warm
mid-level temperatures will preclude buoyancy and deep convection
across much of the TX Coastal Plain.
Greater thunderstorm potential is anticipated farther north in
corridor from the Edwards Plateau into southeast OK and western AR
about 200 mi northwest of the primary synoptic boundary. Here,
aforementioned mass response and associated strengthening of the
low-level southwesterly flow will lead to moderate to strong
low-level warm-air advection and the development of modest elevated
buoyancy (generally above 800-750 mb). Isolated thunderstorms will
be possible as early as this afternoon across southeastern OK and
western AR. Persistent warm-air advection will likely contribute to
a continued potential for isolated thunderstorms across this region
throughout the evening. This persistent warm-air advection will also
help support the development of modest buoyancy into TX as mid-level temperatures cool ahead of the approaching shortwave. Resulting
buoyancy combined with increasing large-scale ascent should result
in addition isolated thunderstorm development from north TX into the
Edwards Plateau, largely after 06Z. Limited buoyancy should keep the
severe potential low throughout the period.
..Mosier/Broyles.. 02/10/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Tue Feb 11 09:54:00 2025
ACUS01 KWNS 111248
SWODY1
SPC AC 111247
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0647 AM CST Tue Feb 11 2025
Valid 111300Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
TEXAS AND THE LOWER MISSISSIPPI VALLEY INTO SOUTHERN MISSISSIPPI AND
CENTRAL ALABAMA....
...SUMMARY...
Isolated to scattered thunderstorms are possible from the southern
Plains into the lower Mississippi Valley. Some strong to severe
thunderstorms are possible from southeast Texas and the Lower
Mississippi Valley into southern Mississippi and central Alabama.
...Synopsis...
A pair of shortwave troughs are expected to progress through the
southern Plains today as the cyclonic flow aloft across the western
CONUS deepens. The first of these shortwaves is currently moving
through the southern High Plains while the second remains off the
coast of the northern Baja Peninsula. Both of those shortwaves are
expected to progress quickly eastward, with the lead wave reaching
the Mid-Atlantic by early Wednesday and the second shortwave
reaching central TX.
...Lower MS Valley into southern/central MS and AL...
As mentioned in the synopsis, the lead shortwave trough is currently
moving through the southern High Plains, with preceding warm-air
advection contributing to an expansive area of precipitation from
the TX Hill Country into the Mid-South. General expectation is that
this area of precipitation will gradually shift northeastward
throughout the day, remaining just ahead of the eastward-progressing
shortwave. Low-level moisture return ahead of the first wave will be
modest, particularly across TX where the modified Gulf moisture will
likely remain confined to the coastal plain. Farther east, greater
inland moisture advection is anticipated, with mid 60s dewpoints
advection through much of the Lower MS Valley by the early
afternoon. Lower 60s dewpoints are likely in the central portions of
MS and AL by the late afternoon/early evening.
Even with this low-level moisture advection, mid-level temperatures
will remain warm, keeping the overall buoyancy modest (i.e. MUCAPE
less than 1000 J/kg) across the region. In contrast to the modest
buoyancy, vertical shear will be quite strong, with effective bulk
shear over 50 kt from the Lower MS Valley into AL and MS during the
afternoon and evening. This strong vertical shear may be able to
compensate for the lower buoyancy, and there could be a window for a
few strong to severe storms this afternoon/evening along and ahead
of the cold front from southern MS into southern and central AL.
Primary risk would be damaging wind gusts, but enough low-level
shear exists for a low-probability tornado threat as well.
...Southern Plains late tonight...
Strong large-scale forcing for ascent will spread across the
southern High Plains and into west TX late tonight ahead of the
second shortwave trough mentioned in the synopsis. Notable
moistening between 850 and 700 mb combined with mid-level cooling
will help support modest elevated buoyancy. Thunderstorms are
expected to develop across West TX tonight before then spreading eastward/northeastward into more of OK and north/central TX. Much of
this activity will be displaced well north/northwest of front and
greater low-level moisture. Some hail is possible, but updraft depth
and duration will be limited by weak buoyancy, and the current
expectation is for any hail to remain very isolated.
As these storms move east/southeast with time, some interaction
could occur with a warm front gradually moving northward into more
of southeast TX early Wednesday morning. Increased buoyancy as well
as enhanced mesoscale ascent in the vicinity of the front is
expected to result in greater thunderstorm depth and duration.
Vertical shear will remain strong as well, with all of these factors
supporting a greater severe potential across southeast TX and
adjacent far southwestern LA early Wednesday morning. Damaging gusts
and/or a brief tornado are the primary threats.
..Mosier/Broyles.. 02/11/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Thu Feb 13 08:45:00 2025
ACUS01 KWNS 131245
SWODY1
SPC AC 131243
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0643 AM CST Thu Feb 13 2025
Valid 131300Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FLORIDA
PANHANDLE INTO SOUTHERN GEORGIA...AND OVER PARTS OF THE CENTRAL
VALLEY OF CALIFORNIA...
...SUMMARY...
Isolated, marginally severe storms are possible from the Florida
Panhandle into southern Georgia and parts of the Central Valley of
California. Damaging winds and a brief tornado are the primary threats.
...Southeast...
Lead shortwave trough continues to progress through the OH Valley
this morning, and is expected to continue northeastward through the
Northeast today. Primary surface low associated with this system is
over the Lower Great Lakes, but a secondary triple point low exists
farther south over west-central GA. A cold front extends
southwestward from this secondary low off the AL coast while a warm
front extends eastward into the SC Lowcountry before arcing
northeastward along the SC and NC coasts. Warm sector between these
two features is characterized by temperatures in the upper 60s/low
70s and dewpoints in the 60s. A convective line is currently
traversing this warm sector, extending from the MMT vicinity in
central SC southwestward to off the FL Panhandle Coast east of ECP.
Modest buoyancy precedes this line across the central FL Panhandle
and southwest/south-central GA, but weakens with northern extent,
with MLCAPE dropping to less than 250 J/kg over southeast GA. In
contrast to this modest buoyancy, strong deep-layer shear extends
across the warm sector, which is contributing to modest updraft
organization within the line and occasional bowing segments. Shear
is expected to weaken throughout the day as the parent shortwave
trough becomes increasingly displaced north and the mid/low level
flow weakens. As a result, the severe potential over this region
today will likely be maximized from now through the next 4 to 6
hours while some overlap between the modest buoyancy and strong
shear exists. A few strong to severe storms are possible,
particularly where the line interacts with the warm front. Damaging
gusts will be the primary risk, but a brief line-embedded tornado is
possible as well.
...Central Valley of California...
Recent satellite imagery depicts an intense cyclone off the West
Coast, with a strong shortwave trough moving through its southern
periphery towards central CA. This shortwave is forecast to reach
the coast later this afternoon, with the ongoing warm-air advection
shower activity moving to the east/south as it does. As these
showers clear out, temperatures should warm into the upper 50s/low
60s while mid-level cold-air advection results in 500-mb
temperatures in the -22 to -25 deg C range. This will support weak
airmass destabilization, with modest buoyancy anticipated during the
afternoon. This could result in some deeper, more sustained
convection. Vertical shear will be strong enough to support
transient rotation within any deeper updrafts, yielding a localized
wind/brief tornado risk during the late afternoon.
..Mosier/Broyles.. 02/13/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Thu Feb 13 18:02:00 2025
ACUS01 KWNS 132053
SWODY1
SPC AC 131947
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0147 PM CST Thu Feb 13 2025
Valid 132000Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL VALLEY OF CALIFORNIA...
...SUMMARY...
Isolated, marginally severe storms are possible in parts of the
Central Valley of California. Damaging winds and a brief tornado are
the primary threats.
...Central Valley of California...
Satellite imagery depicts an intense cyclone off the West Coast,
with a strong shortwave trough moving through its southern periphery
towards central CA. Clearing behind morning showers associated with
WAA has allowed surface temperatures to rise into the upper 50s,
with dew points reaching the low 50s. Upper level cold-air advection
will result in 500-mb temperatures in the -22 to -25 deg C range,
supporting weak airmass destabilization through this afternoon. With
favorable shear profiles, current expectations is for a few stronger
updrafts to take on transient supercell structures within the
Central Valley, with the threat for marginally damaging winds and
perhaps a brief tornado or two.
...Southeast...
The lead shortwave trough continues to progress through the OH
Valley this afternoon, and is expected to continue northeastward
through the Northeast into tonight. The surface low associated with
this system continues to progress northeastward into far northern
New England/southern Quebec. A cold front extends southwestward from
this low through the eastern seaboard and off the Florida Coast.
Although MUCAPE has approached 1500-2000 j/kg ahead of the front,
deep layer shear has continued to decrease as the strongest dynamics
continue to depart as the trough progresses further northeast, and
boundary parallel flow will likely suppress any significant updraft organization. In turn, midday convection has continued to weaken,
with additional weakening expected through the rest of the
afternoon. Have opted to drop the marginal risk across the Florida
panhandle. A few brief gusts of winds are still possible with any
stronger updrafts, but any severe threat remaining appears to be minute.
..15_ows.. 02/13/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)
-
From
Dumas Walker@21:1/175 to
All on Mon Feb 24 08:44:00 2025
ACUS01 KWNS 241231
SWODY1
SPC AC 241230
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0630 AM CST Mon Feb 24 2025
Valid 241300Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER FAR
SOUTHERN FL INCLUDING THE KEYS...AND OVER PARTS OF EASTERN OR AND WA...
...SUMMARY...
Scattered strong storms will be possible across the Florida Keys and
into far southern Florida from late afternoon through evening.
Localized damaging gusts or a brief tornado may occur. Isolated
strong winds are also expected from the Oregon Cascades into
southeast Washington.
...Far Southern FL and the FL Keys...
Shortwave trough currently progressing off the TX Coast is expected
to continue eastward across the Gulf today, reaching the FL
Peninsula by early tomorrow morning. Cold mid-level temperatures and strengthening mid-level flow that accompany this shortwave are
expected to spread over central/southern FL and the FL Keys after
03Z. An attendant surface low attendant will progress quickly
eastward just ahead of the parent shortwave. The general consensus
among the guidance is for this low to be just off the west-central
FL Coast around 00Z before continuing across the central FL
Peninsula and into the western Atlantic by 12Z Tuesday.
Moistening of the low-level airmass is expected ahead of the
shortwave trough and attendant surface low, particularly after 18Z.
Widespread showers throughout the day will likely mitigate buoyancy
somewhat, but little to no surface-based inhibition is expected
south of the warm front (which will extend eastward from the surface
low across the central FL Peninsula) from the late afternoon onward. Thunderstorm coverage should increase along and ahead of the front
as it gradually pushes eastward.
Dewpoints near 70s across south FL and the FL Keys will result in
stronger buoyancy and the potential for deeper, more long-lived
updrafts. Strong vertical shear over the region supports the
potential for a few supercells with an attendant risk for damaging
wind gusts and a brief tornado or two. The development of a
low-level convergence zone is possible, which could result in a
favored corridor for strong to severe storms. Currently, this zone
is expected to remain just off south FL Coast, but a few storms in
this area could impact the Keys.
...Interior Pacific Northwest...
Recent satellite imagery shows an intense shortwave trough off the
Pacific Northwest coast, moving quickly northeastward. This
shortwave is forecast to continue northeastward throughout the day,
reaching the coastal Pacific Northwest this afternoon and the
interior Pacific Northwest tonight. A frontal band, with occasional
lightning, is expected to develop along the leading edge of the
strong forcing for ascent associated with this system. Temperatures
could reach the upper 50s/low 60s ahead of this line in northeast
OR/southwest WA amid steep low-level lapse rates and modest
buoyancy. As such, the overall environment supports the potential
for strong downbursts within the line as it moves across the region.
...Eastern Dakotas into the Mid MS Valley...
The low-amplitude shortwave trough currently moving through MT is
expected to continue southeastward today, moving across the northern
Plains and IA before ending the period over IL. A compact but strong
jet streak will accompany this shortwave, with 500-mb winds within
this streak from 90 to 100 kt. The downstream airmass will be dry,
and strong heating/mixing will help push afternoon temperatures into
the upper 50s and low 60s. Despite dry low levels, some modest
buoyancy is possible amid the deep mixing and cold mid-level
temperatures. Consequently, a few shallow thunderstorms are possible
as the strong forcing for ascent attendant to the shortwave
interacts with this limited buoyancy. Small hail and strong outflow
is possible with these storms, but overall coverage is currently
expected to remain too isolated to introduce any probabilities.
..Mosier/Grams.. 02/24/2025
$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)