2 years 2 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1218 PM CDT Tue May 16 2023
Valid 171200Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY
AFTERNOON AND EVENING ACROSS PARTS OF THE SOUTHEAST AND HIGH
PLAINS...
...SUMMARY...
Scattered thunderstorm clusters may develop across parts of the
Southeast Wednesday afternoon, and from the Rockies into the
adjacent Great Plains by Wednesday evening. A few of these may be
accompanied by strong to locally severe wind gusts.
...Synopsis...
Mid/upper flow across the northern mid-latitudes of the Pacific into
Atlantic remains amplified, with a number of embedded highs and lows
in various states of evolution. The center of one mid-level high
may slowly shift from the British Columbia coast vicinity into
northern British Columbia, as one perturbation progresses around its
eastern through southern periphery, across the Canadian Rockies by
late Wednesday night. Downstream, a deeper mid-level low is
forecast to dig south of the eastern Canadian Prairies into the
central Canadian/U.S. Border area, while an even more prominent low
and associated mid-level troughing pivot offshore of the northern
Atlantic coast, and across the Canadian Maritimes.
In the wake of the lead perturbation, a broadly confluent mid-level
regime will slowly begin to shift east of the Atlantic Seaboard,
with weak low-amplitude troughing shifting east of the middle
Mississippi Valley and across the central Gulf of Mexico. In lower
levels, models indicate that the center of seasonably cold surface
ridging will build southeast of the upper Great Lakes into the Mid
Atlantic by 12Z Thursday, with the cold front on the leading edge of
this air mass advancing southward and southwestward through the
Carolinas, Tennessee and middle Mississippi Valleys. Ahead of the
front, seasonably warm and moist air will generally be maintained
across parts of the eastern Gulf/south Atlantic Coast states through
at least much of this period.
Another fairly significant cold intrusion is forecast to accompany
the trailing mid-level perturbation, across and to the lee of the
northern U.S. Rockies. Although boundary-layer moisture preceding
the associated cold front appears likely to remain seasonably
modest, stronger surface heating and deep boundary-layer mixing
within a corridor across the higher plains probably will become a
focus for destabilization and thunderstorm development.
...Southeast...
Beneath broadly cyclonic westerly mid-level flow, boundary-layer
moisture (characterized by mid 60s to around 70F surface dew points)
may support mixed-layer CAPE on the order of 1000-2000 J/kg in a
corridor roughly centered from central Mississippi into southern
South Carolina by late Wednesday afternoon. It appears that this
environment will become supportive of fairly widespread thunderstorm
development from mid afternoon into early evening. Despite ambient
westerly deep-layer mean wind speeds near or below 20 kt, this may
be sufficient to contribute to localized damaging wind gusts, aided
by modestly steep low-level lapse rates and precipitation loading.
...Rockies into adjacent Great Plains...
Much of the region will remain south of the influence of the primary
digging low, but forcing for ascent downstream of weak northern
(across the Great Basin) and southern (near Baja California) branch
troughing may provide support for scattered thunderstorm development
across and east of the Rockies. Beneath generally weak
west-northwesterly deep-layer mean flow, this activity will tend to
advect off the higher terrain through Wednesday evening. As
convection spreads into the Great Plains, the warm and deeply mixed
boundary-layer may possess sufficient moisture and CAPE to support
upscale growing clusters with increasing potential to produce strong
wind gusts, before boundary-layer instability wanes later Wednesday
evening.
..Kerr.. 05/16/2023
Read more2 years 3 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0319 PM CDT Mon May 15 2023
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF SOUTHERN MISSOURI...NORTHERN
ARKANSAS...FAR SOUTHERN ILLINOIS...WESTERN KENTUCKY AND WESTERN AND
MIDDLE TENNESSEE...
CORRECTED GRAPHIC
...SUMMARY...
Marginally severe thunderstorms producing a few strong wind gusts
and hail will be possible today from parts of the Ozarks into the
Tennessee Valley vicinity.
...20Z Update...
Some adjustments to the categorical and probabilistic outlook lines
have been made, but mostly just to account for the slow progression
of the synoptic/sub-synoptic features and associated trends
concerning destabilization.
Please refer to the 1630Z outlook discussion (appended below) and
the latest SPC mesoscale discussions for further details.
..Kerr.. 05/15/2023
.PREV DISCUSSION... /ISSUED 1112 AM CDT Mon May 15 2023/
...Ozarks to TN Valley vicinity...
An upper ridge will persist over the Southeast much of today, while
a rather nondescript/weak flow regime remains in place across the
Plains. At the surface, a weak low/MCV is featured over eastern OK
late this morning. This feature will slowly migrate east/northeast
through southern MO through the period. Abundant boundary-layer
moisture (surface dewpoints in the upper 60s to near 70 F) and
heating into upper 70s/low 80s F will support weak to moderate
destabilization ahead of the MCV. Deep-layer flow will remain light,
though the MCV will likely enhance low/midlevel winds modestly,
providing around 25 kt effective shear magnitudes. This should
support some loosely organized, sporadically strong cells/bows.
Strong/locally damaging gusts and hail will be the main hazards with
this activity. While low-level flow will remain very weak,
vertically veering winds in the lowest 1-2 km will produce very
modestly curved hodographs with some minor SRH ahead of the MCV in
conjunction with mean mixing ratios near 15-16 g/kg. Tornado
potential is expected to remain very low, but a funnel cloud or
brief spin-up could occur this afternoon, mainly across southern MO.
Further east toward Middle TN into adjacent portions of northern
AL/extreme northwest GA, shear profile will be even more modest,
mainly relegating afternoon activity to pulse-like convection.
However, stronger instability and a more deeply mixed boundary-layer
could support potential for water-loaded downdrafts and isolated
downbursts producing locally strong gusts with any more transient
intense cells this afternoon. The strongest cells could also produce
small hail.
Read more2 years 3 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0319 PM CDT Mon May 15 2023
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF SOUTHERN MISSOURI...NORTHERN
ARKANSAS...FAR SOUTHERN ILLINOIS...WESTERN KENTUCKY AND WESTERN AND
MIDDLE TENNESSEE...
CORRECTED GRAPHIC
...SUMMARY...
Marginally severe thunderstorms producing a few strong wind gusts
and hail will be possible today from parts of the Ozarks into the
Tennessee Valley vicinity.
...20Z Update...
Some adjustments to the categorical and probabilistic outlook lines
have been made, but mostly just to account for the slow progression
of the synoptic/sub-synoptic features and associated trends
concerning destabilization.
Please refer to the 1630Z outlook discussion (appended below) and
the latest SPC mesoscale discussions for further details.
..Kerr.. 05/15/2023
.PREV DISCUSSION... /ISSUED 1112 AM CDT Mon May 15 2023/
...Ozarks to TN Valley vicinity...
An upper ridge will persist over the Southeast much of today, while
a rather nondescript/weak flow regime remains in place across the
Plains. At the surface, a weak low/MCV is featured over eastern OK
late this morning. This feature will slowly migrate east/northeast
through southern MO through the period. Abundant boundary-layer
moisture (surface dewpoints in the upper 60s to near 70 F) and
heating into upper 70s/low 80s F will support weak to moderate
destabilization ahead of the MCV. Deep-layer flow will remain light,
though the MCV will likely enhance low/midlevel winds modestly,
providing around 25 kt effective shear magnitudes. This should
support some loosely organized, sporadically strong cells/bows.
Strong/locally damaging gusts and hail will be the main hazards with
this activity. While low-level flow will remain very weak,
vertically veering winds in the lowest 1-2 km will produce very
modestly curved hodographs with some minor SRH ahead of the MCV in
conjunction with mean mixing ratios near 15-16 g/kg. Tornado
potential is expected to remain very low, but a funnel cloud or
brief spin-up could occur this afternoon, mainly across southern MO.
Further east toward Middle TN into adjacent portions of northern
AL/extreme northwest GA, shear profile will be even more modest,
mainly relegating afternoon activity to pulse-like convection.
However, stronger instability and a more deeply mixed boundary-layer
could support potential for water-loaded downdrafts and isolated
downbursts producing locally strong gusts with any more transient
intense cells this afternoon. The strongest cells could also produce
small hail.
Read more2 years 3 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0319 PM CDT Mon May 15 2023
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF SOUTHERN MISSOURI...NORTHERN
ARKANSAS...FAR SOUTHERN ILLINOIS...WESTERN KENTUCKY AND WESTERN AND
MIDDLE TENNESSEE...
CORRECTED GRAPHIC
...SUMMARY...
Marginally severe thunderstorms producing a few strong wind gusts
and hail will be possible today from parts of the Ozarks into the
Tennessee Valley vicinity.
...20Z Update...
Some adjustments to the categorical and probabilistic outlook lines
have been made, but mostly just to account for the slow progression
of the synoptic/sub-synoptic features and associated trends
concerning destabilization.
Please refer to the 1630Z outlook discussion (appended below) and
the latest SPC mesoscale discussions for further details.
..Kerr.. 05/15/2023
.PREV DISCUSSION... /ISSUED 1112 AM CDT Mon May 15 2023/
...Ozarks to TN Valley vicinity...
An upper ridge will persist over the Southeast much of today, while
a rather nondescript/weak flow regime remains in place across the
Plains. At the surface, a weak low/MCV is featured over eastern OK
late this morning. This feature will slowly migrate east/northeast
through southern MO through the period. Abundant boundary-layer
moisture (surface dewpoints in the upper 60s to near 70 F) and
heating into upper 70s/low 80s F will support weak to moderate
destabilization ahead of the MCV. Deep-layer flow will remain light,
though the MCV will likely enhance low/midlevel winds modestly,
providing around 25 kt effective shear magnitudes. This should
support some loosely organized, sporadically strong cells/bows.
Strong/locally damaging gusts and hail will be the main hazards with
this activity. While low-level flow will remain very weak,
vertically veering winds in the lowest 1-2 km will produce very
modestly curved hodographs with some minor SRH ahead of the MCV in
conjunction with mean mixing ratios near 15-16 g/kg. Tornado
potential is expected to remain very low, but a funnel cloud or
brief spin-up could occur this afternoon, mainly across southern MO.
Further east toward Middle TN into adjacent portions of northern
AL/extreme northwest GA, shear profile will be even more modest,
mainly relegating afternoon activity to pulse-like convection.
However, stronger instability and a more deeply mixed boundary-layer
could support potential for water-loaded downdrafts and isolated
downbursts producing locally strong gusts with any more transient
intense cells this afternoon. The strongest cells could also produce
small hail.
Read more2 years 3 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0319 PM CDT Mon May 15 2023
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF SOUTHERN MISSOURI...NORTHERN
ARKANSAS...FAR SOUTHERN ILLINOIS...WESTERN KENTUCKY AND WESTERN AND
MIDDLE TENNESSEE...
CORRECTED GRAPHIC
...SUMMARY...
Marginally severe thunderstorms producing a few strong wind gusts
and hail will be possible today from parts of the Ozarks into the
Tennessee Valley vicinity.
...20Z Update...
Some adjustments to the categorical and probabilistic outlook lines
have been made, but mostly just to account for the slow progression
of the synoptic/sub-synoptic features and associated trends
concerning destabilization.
Please refer to the 1630Z outlook discussion (appended below) and
the latest SPC mesoscale discussions for further details.
..Kerr.. 05/15/2023
.PREV DISCUSSION... /ISSUED 1112 AM CDT Mon May 15 2023/
...Ozarks to TN Valley vicinity...
An upper ridge will persist over the Southeast much of today, while
a rather nondescript/weak flow regime remains in place across the
Plains. At the surface, a weak low/MCV is featured over eastern OK
late this morning. This feature will slowly migrate east/northeast
through southern MO through the period. Abundant boundary-layer
moisture (surface dewpoints in the upper 60s to near 70 F) and
heating into upper 70s/low 80s F will support weak to moderate
destabilization ahead of the MCV. Deep-layer flow will remain light,
though the MCV will likely enhance low/midlevel winds modestly,
providing around 25 kt effective shear magnitudes. This should
support some loosely organized, sporadically strong cells/bows.
Strong/locally damaging gusts and hail will be the main hazards with
this activity. While low-level flow will remain very weak,
vertically veering winds in the lowest 1-2 km will produce very
modestly curved hodographs with some minor SRH ahead of the MCV in
conjunction with mean mixing ratios near 15-16 g/kg. Tornado
potential is expected to remain very low, but a funnel cloud or
brief spin-up could occur this afternoon, mainly across southern MO.
Further east toward Middle TN into adjacent portions of northern
AL/extreme northwest GA, shear profile will be even more modest,
mainly relegating afternoon activity to pulse-like convection.
However, stronger instability and a more deeply mixed boundary-layer
could support potential for water-loaded downdrafts and isolated
downbursts producing locally strong gusts with any more transient
intense cells this afternoon. The strongest cells could also produce
small hail.
Read more2 years 3 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1245 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
Elevated highlights have been introduced for portions of Coastal New
England. Here, the latest guidance consensus depicts dry and breezy
conditions capable of supporting wildfire spread on a potentially
widespread basis. By Tuesday afternoon, an upper trough will deepen
over New England, with 50+ kts of northwesterly flow overspreading
the region. The deepening upper trough will also encourage
strengthening surface lee troughing, with surface west-southwesterly
winds sustaining over 15 mph. Given the presence of a lingering
deep, dry boundary layer extending up to 500 mb (per 12Z Day 1
observed regional soundings), surface heating will encourage RH to
drop below 30 percent on a widespread basis (perhaps down to 20
percent locally). Finally, fuel guidance indicates 100-h fuel
moisture values may drop into the 10-15 percent range as ERCs
potentially exceed the 80th percentile in spots. This level of fuel
receptiveness, along with the lack of forecast rainfall and
anticipated dry and breezy conditions warrants the introduction of
Elevated highlights.
..Squitieri.. 05/15/2023
.PREV DISCUSSION... /ISSUED 0201 AM CDT Mon May 15 2023/
...Synopsis...
Within the base of a midlevel low/trough over northern Quebec,
strong deep-layer westerly flow will overspread the Northeast --
where a dry antecedent air mass is in place. A narrow corridor of
partly cloudy skies from south-central NY into CT/MA will aid in
deep boundary-layer mixing into the dry/enhanced flow aloft -- where
15-20 percent minimum RH is possible. These dry conditions, coupled
with sustained westerly surface winds near 15 mph (with higher
gusts) could yield elevated fire-weather conditions during the
afternoon. Currently, these conditions appear too localized for
highlights, though trends will be monitored.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more2 years 3 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1245 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
Elevated highlights have been introduced for portions of Coastal New
England. Here, the latest guidance consensus depicts dry and breezy
conditions capable of supporting wildfire spread on a potentially
widespread basis. By Tuesday afternoon, an upper trough will deepen
over New England, with 50+ kts of northwesterly flow overspreading
the region. The deepening upper trough will also encourage
strengthening surface lee troughing, with surface west-southwesterly
winds sustaining over 15 mph. Given the presence of a lingering
deep, dry boundary layer extending up to 500 mb (per 12Z Day 1
observed regional soundings), surface heating will encourage RH to
drop below 30 percent on a widespread basis (perhaps down to 20
percent locally). Finally, fuel guidance indicates 100-h fuel
moisture values may drop into the 10-15 percent range as ERCs
potentially exceed the 80th percentile in spots. This level of fuel
receptiveness, along with the lack of forecast rainfall and
anticipated dry and breezy conditions warrants the introduction of
Elevated highlights.
..Squitieri.. 05/15/2023
.PREV DISCUSSION... /ISSUED 0201 AM CDT Mon May 15 2023/
...Synopsis...
Within the base of a midlevel low/trough over northern Quebec,
strong deep-layer westerly flow will overspread the Northeast --
where a dry antecedent air mass is in place. A narrow corridor of
partly cloudy skies from south-central NY into CT/MA will aid in
deep boundary-layer mixing into the dry/enhanced flow aloft -- where
15-20 percent minimum RH is possible. These dry conditions, coupled
with sustained westerly surface winds near 15 mph (with higher
gusts) could yield elevated fire-weather conditions during the
afternoon. Currently, these conditions appear too localized for
highlights, though trends will be monitored.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more2 years 3 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1245 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
Elevated highlights have been introduced for portions of Coastal New
England. Here, the latest guidance consensus depicts dry and breezy
conditions capable of supporting wildfire spread on a potentially
widespread basis. By Tuesday afternoon, an upper trough will deepen
over New England, with 50+ kts of northwesterly flow overspreading
the region. The deepening upper trough will also encourage
strengthening surface lee troughing, with surface west-southwesterly
winds sustaining over 15 mph. Given the presence of a lingering
deep, dry boundary layer extending up to 500 mb (per 12Z Day 1
observed regional soundings), surface heating will encourage RH to
drop below 30 percent on a widespread basis (perhaps down to 20
percent locally). Finally, fuel guidance indicates 100-h fuel
moisture values may drop into the 10-15 percent range as ERCs
potentially exceed the 80th percentile in spots. This level of fuel
receptiveness, along with the lack of forecast rainfall and
anticipated dry and breezy conditions warrants the introduction of
Elevated highlights.
..Squitieri.. 05/15/2023
.PREV DISCUSSION... /ISSUED 0201 AM CDT Mon May 15 2023/
...Synopsis...
Within the base of a midlevel low/trough over northern Quebec,
strong deep-layer westerly flow will overspread the Northeast --
where a dry antecedent air mass is in place. A narrow corridor of
partly cloudy skies from south-central NY into CT/MA will aid in
deep boundary-layer mixing into the dry/enhanced flow aloft -- where
15-20 percent minimum RH is possible. These dry conditions, coupled
with sustained westerly surface winds near 15 mph (with higher
gusts) could yield elevated fire-weather conditions during the
afternoon. Currently, these conditions appear too localized for
highlights, though trends will be monitored.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more2 years 3 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON
AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN KENTUCKY...EASTERN
TENNESSEE...SOUTHWESTERN INTO SOUTH CENTRAL VIRGINIA...WESTERN AND
CENTRAL NORTH CAROLINA....UPSTATE SOUTH CAROLINA AND ADJACENT
NORTHEASTERN GEORGIA...
...SUMMARY...
Clusters of thunderstorms may form and gradually consolidate across
parts of the Tennessee Valley and Cumberland Plateau through the
Appalachian Piedmont Tuesday afternoon and evening. Some of these
storms may initially be accompanied by a risk for severe hail,
before strong wind gusts become the more prominent potential severe
hazard.
...Synopsis...
A vigorous short wave impulse digging around the western through
southwestern periphery of a mid-level low, now digging into northern
Quebec, may contribute to elongation of the low and/or amplification
of larger-scale, positively tilted mid-level troughing across much
of the Northeast during this period. As this occurs, it appears
likely to be accompanied by a significant surface cold front, which
is forecast to surge south of the St. Lawrence Valley and upper
Great Lakes region, into the northern Mid Atlantic coast, upper Ohio
and Mississippi Valleys by 12Z Wednesday. A stalled, or slower
moving, and weaker preceding front, initially extending across the
Mid Atlantic coast into the lower Ohio Valley and southern Great
Plains, may advance southward into the Tennessee Valley and through
the southern Mid Atlantic coast, in response to the progression of a
weak frontal wave.
Upstream of the broadly confluent mid-level regime evolving east of
the Mississippi Valley, models indicate that mid-level ridging will
build across British Columbia, with an embedded high evolving, in
the wake of a significant short wave perturbation digging into the
Canadian Prairies. It appears that the latter feature will be
accompanied by lower/mid-tropospheric cyclogenesis, and another cold
front which may advance across the international border to the east
of the northern Rockies by 12Z Wednesday.
...Lower Ohio/Tennessee Valleys into Mid Atlantic...
Along and ahead of the initially stalled or slow moving surface
front, a seasonably moist boundary-layer across the lower Ohio and
Tennessee Valleys is forecast to destabilize with daytime heating,
while also advecting across the Appalachians, toward the Mid
Atlantic, during the day. Despite the presence of only modestly
cool mid-level temperatures, with generally weak lapse rates, this
moisture may become supportive of mixed-layer CAPE on the order of
1000-2000 J/kg (with larger CAPE remaining west of the Appalachians)
along the frontal zone.
Beneath a corridor of strengthening westerly flow in the 850-500 mb
layer (on the order of 30-50 kt), it appears that the environment
will become potentially supportive of organized convective
development. Initiation of storms may be aided by a couple of
perturbations progressing through the evolving and amplifying
larger-scale cyclonic mid-level flow, with convection tending to
grow upscale and perhaps gradually consolidate into one
east-southeastward propagating cluster and associated surface cold
pool, accompanied by potentially damaging wind gusts.
..Kerr.. 05/15/2023
Read more2 years 3 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON
AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN KENTUCKY...EASTERN
TENNESSEE...SOUTHWESTERN INTO SOUTH CENTRAL VIRGINIA...WESTERN AND
CENTRAL NORTH CAROLINA....UPSTATE SOUTH CAROLINA AND ADJACENT
NORTHEASTERN GEORGIA...
...SUMMARY...
Clusters of thunderstorms may form and gradually consolidate across
parts of the Tennessee Valley and Cumberland Plateau through the
Appalachian Piedmont Tuesday afternoon and evening. Some of these
storms may initially be accompanied by a risk for severe hail,
before strong wind gusts become the more prominent potential severe
hazard.
...Synopsis...
A vigorous short wave impulse digging around the western through
southwestern periphery of a mid-level low, now digging into northern
Quebec, may contribute to elongation of the low and/or amplification
of larger-scale, positively tilted mid-level troughing across much
of the Northeast during this period. As this occurs, it appears
likely to be accompanied by a significant surface cold front, which
is forecast to surge south of the St. Lawrence Valley and upper
Great Lakes region, into the northern Mid Atlantic coast, upper Ohio
and Mississippi Valleys by 12Z Wednesday. A stalled, or slower
moving, and weaker preceding front, initially extending across the
Mid Atlantic coast into the lower Ohio Valley and southern Great
Plains, may advance southward into the Tennessee Valley and through
the southern Mid Atlantic coast, in response to the progression of a
weak frontal wave.
Upstream of the broadly confluent mid-level regime evolving east of
the Mississippi Valley, models indicate that mid-level ridging will
build across British Columbia, with an embedded high evolving, in
the wake of a significant short wave perturbation digging into the
Canadian Prairies. It appears that the latter feature will be
accompanied by lower/mid-tropospheric cyclogenesis, and another cold
front which may advance across the international border to the east
of the northern Rockies by 12Z Wednesday.
...Lower Ohio/Tennessee Valleys into Mid Atlantic...
Along and ahead of the initially stalled or slow moving surface
front, a seasonably moist boundary-layer across the lower Ohio and
Tennessee Valleys is forecast to destabilize with daytime heating,
while also advecting across the Appalachians, toward the Mid
Atlantic, during the day. Despite the presence of only modestly
cool mid-level temperatures, with generally weak lapse rates, this
moisture may become supportive of mixed-layer CAPE on the order of
1000-2000 J/kg (with larger CAPE remaining west of the Appalachians)
along the frontal zone.
Beneath a corridor of strengthening westerly flow in the 850-500 mb
layer (on the order of 30-50 kt), it appears that the environment
will become potentially supportive of organized convective
development. Initiation of storms may be aided by a couple of
perturbations progressing through the evolving and amplifying
larger-scale cyclonic mid-level flow, with convection tending to
grow upscale and perhaps gradually consolidate into one
east-southeastward propagating cluster and associated surface cold
pool, accompanied by potentially damaging wind gusts.
..Kerr.. 05/15/2023
Read more2 years 3 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON
AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN KENTUCKY...EASTERN
TENNESSEE...SOUTHWESTERN INTO SOUTH CENTRAL VIRGINIA...WESTERN AND
CENTRAL NORTH CAROLINA....UPSTATE SOUTH CAROLINA AND ADJACENT
NORTHEASTERN GEORGIA...
...SUMMARY...
Clusters of thunderstorms may form and gradually consolidate across
parts of the Tennessee Valley and Cumberland Plateau through the
Appalachian Piedmont Tuesday afternoon and evening. Some of these
storms may initially be accompanied by a risk for severe hail,
before strong wind gusts become the more prominent potential severe
hazard.
...Synopsis...
A vigorous short wave impulse digging around the western through
southwestern periphery of a mid-level low, now digging into northern
Quebec, may contribute to elongation of the low and/or amplification
of larger-scale, positively tilted mid-level troughing across much
of the Northeast during this period. As this occurs, it appears
likely to be accompanied by a significant surface cold front, which
is forecast to surge south of the St. Lawrence Valley and upper
Great Lakes region, into the northern Mid Atlantic coast, upper Ohio
and Mississippi Valleys by 12Z Wednesday. A stalled, or slower
moving, and weaker preceding front, initially extending across the
Mid Atlantic coast into the lower Ohio Valley and southern Great
Plains, may advance southward into the Tennessee Valley and through
the southern Mid Atlantic coast, in response to the progression of a
weak frontal wave.
Upstream of the broadly confluent mid-level regime evolving east of
the Mississippi Valley, models indicate that mid-level ridging will
build across British Columbia, with an embedded high evolving, in
the wake of a significant short wave perturbation digging into the
Canadian Prairies. It appears that the latter feature will be
accompanied by lower/mid-tropospheric cyclogenesis, and another cold
front which may advance across the international border to the east
of the northern Rockies by 12Z Wednesday.
...Lower Ohio/Tennessee Valleys into Mid Atlantic...
Along and ahead of the initially stalled or slow moving surface
front, a seasonably moist boundary-layer across the lower Ohio and
Tennessee Valleys is forecast to destabilize with daytime heating,
while also advecting across the Appalachians, toward the Mid
Atlantic, during the day. Despite the presence of only modestly
cool mid-level temperatures, with generally weak lapse rates, this
moisture may become supportive of mixed-layer CAPE on the order of
1000-2000 J/kg (with larger CAPE remaining west of the Appalachians)
along the frontal zone.
Beneath a corridor of strengthening westerly flow in the 850-500 mb
layer (on the order of 30-50 kt), it appears that the environment
will become potentially supportive of organized convective
development. Initiation of storms may be aided by a couple of
perturbations progressing through the evolving and amplifying
larger-scale cyclonic mid-level flow, with convection tending to
grow upscale and perhaps gradually consolidate into one
east-southeastward propagating cluster and associated surface cold
pool, accompanied by potentially damaging wind gusts.
..Kerr.. 05/15/2023
Read more2 years 3 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Mon May 15 2023
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON
AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN KENTUCKY...EASTERN
TENNESSEE...SOUTHWESTERN INTO SOUTH CENTRAL VIRGINIA...WESTERN AND
CENTRAL NORTH CAROLINA....UPSTATE SOUTH CAROLINA AND ADJACENT
NORTHEASTERN GEORGIA...
...SUMMARY...
Clusters of thunderstorms may form and gradually consolidate across
parts of the Tennessee Valley and Cumberland Plateau through the
Appalachian Piedmont Tuesday afternoon and evening. Some of these
storms may initially be accompanied by a risk for severe hail,
before strong wind gusts become the more prominent potential severe
hazard.
...Synopsis...
A vigorous short wave impulse digging around the western through
southwestern periphery of a mid-level low, now digging into northern
Quebec, may contribute to elongation of the low and/or amplification
of larger-scale, positively tilted mid-level troughing across much
of the Northeast during this period. As this occurs, it appears
likely to be accompanied by a significant surface cold front, which
is forecast to surge south of the St. Lawrence Valley and upper
Great Lakes region, into the northern Mid Atlantic coast, upper Ohio
and Mississippi Valleys by 12Z Wednesday. A stalled, or slower
moving, and weaker preceding front, initially extending across the
Mid Atlantic coast into the lower Ohio Valley and southern Great
Plains, may advance southward into the Tennessee Valley and through
the southern Mid Atlantic coast, in response to the progression of a
weak frontal wave.
Upstream of the broadly confluent mid-level regime evolving east of
the Mississippi Valley, models indicate that mid-level ridging will
build across British Columbia, with an embedded high evolving, in
the wake of a significant short wave perturbation digging into the
Canadian Prairies. It appears that the latter feature will be
accompanied by lower/mid-tropospheric cyclogenesis, and another cold
front which may advance across the international border to the east
of the northern Rockies by 12Z Wednesday.
...Lower Ohio/Tennessee Valleys into Mid Atlantic...
Along and ahead of the initially stalled or slow moving surface
front, a seasonably moist boundary-layer across the lower Ohio and
Tennessee Valleys is forecast to destabilize with daytime heating,
while also advecting across the Appalachians, toward the Mid
Atlantic, during the day. Despite the presence of only modestly
cool mid-level temperatures, with generally weak lapse rates, this
moisture may become supportive of mixed-layer CAPE on the order of
1000-2000 J/kg (with larger CAPE remaining west of the Appalachians)
along the frontal zone.
Beneath a corridor of strengthening westerly flow in the 850-500 mb
layer (on the order of 30-50 kt), it appears that the environment
will become potentially supportive of organized convective
development. Initiation of storms may be aided by a couple of
perturbations progressing through the evolving and amplifying
larger-scale cyclonic mid-level flow, with convection tending to
grow upscale and perhaps gradually consolidate into one
east-southeastward propagating cluster and associated surface cold
pool, accompanied by potentially damaging wind gusts.
..Kerr.. 05/15/2023
Read more2 years 3 months ago
000
ABPZ20 KNHC 151714
TWOEP
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon May 15 2023
For the eastern North Pacific...east of 140 degrees west longitude:
Tropical cyclone formation is not expected during the next 7 days.
Today marks the first day of the eastern North Pacific hurricane
season, which will run until November 30. Long-term averages for
the number of named storms, hurricanes, and major hurricanes are
15, 8, and 4, respectively.
The list of names for 2023 is as follows:
Name Pronunciation Name Pronunciation
-------------------------------------------------------------
Adrian AY-dree-uhn Max maks
Beatriz BEE-a-triz Norma NOOR-muh
Calvin KAL-vin Otis OH-tis
Dora DOR-ruh Pilar Pee-LAHR
Eugene YOU-jeen Ramon rah-MOHN
Fernanda fer-NAN-dah Selma SELL-mah
Greg greg Todd tahd
Hilary HIH-luh-ree Veronica vur-RAHN-ih-kuh
Irwin UR-win Wiley WY-lee
Jova HO-vah Xina ZEE-nah
Kenneth KEH-neth York york
Lidia LIH-dyah Zelda ZEL-dah
This product, the Tropical Weather Outlook, briefly describes
significant areas of disturbed weather and their potential for
tropical cyclone formation during the next seven days. The issuance
times of this product are 5 AM, 11 AM, 5 PM, and 11 PM PDT. After
the change to standard time in November, the issuance times are
4 AM, 10 AM, 4 PM, and 10 PM PST.
A Special Tropical Weather Outlook will be issued to provide
updates, as necessary, in between the regularly scheduled issuances
of the Tropical Weather Outlook. Special Tropical Weather Outlooks
will be issued under the same WMO and AWIPS headers as the regular
Tropical Weather Outlooks.
A standard package of products, consisting of the tropical cyclone
public advisory, the forecast/advisory, the cyclone discussion, and
a wind speed probability product, is issued every six hours for all
ongoing tropical cyclones. In addition, a special advisory package
may be issued at any time to advise of significant unexpected
changes or to modify watches or warnings.
NHC has the option to issue advisories, watches, and warnings for
disturbances that are not yet a tropical cyclone, but which pose
the threat of bringing tropical storm or hurricane conditions to
land areas within 48 hours. For these land-threatening "potential
tropical cyclones", NHC will issue the full suite of advisory and
watch/warning products. Potential tropical cyclones share the
naming conventions currently in place for tropical depressions,
being numbered from a single list (e.g., "One-E", "Two-E",
"Three-E", etc.).
The Tropical Cyclone Update is a brief statement to inform of
significant changes in a tropical cyclone, to post or cancel
watches or warnings, or to provide hourly position updates between
intermediate advisories when the storm center is easily followed by
radar. The Tropical Cyclone Update is also used in lieu of or to
precede the issuance of a special advisory package. Tropical
Cyclone Updates, which can be issued at any time, can be found
under WMO header WTPZ61-65 KNHC, and under AWIPS header MIATCUEP1-5.
All NHC text and graphical products are available on the web at
https://www.hurricanes.gov. More information on NHC text products
can be found at https://www.hurricanes.gov/aboutnhcprod.shtml,
while more information about NHC graphical products can be
found at https://www.hurricanes.gov/aboutnhcgraphics.shtml.
You can also interact with NHC on Facebook at
https://www.facebook.com/NWSNHC. Notifications are available
via Twitter when select NHC products are issued. Information
about our east Pacific Twitter feed is available at
https://www.hurricanes.gov/twitter.php.
$$
Forecaster Kelly/Cangialosi
NHC Webmaster
