RSS Mesoscale Discussions from Storm Prediction Center
WW 274 TORNADO AL FL MS CW 261245Z - 261900Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 274
NWS Storm Prediction Center Norman OK
745 AM CDT Thu May 26 2022
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Southern Alabama
Panhandle of Florida
Extreme southeastern Mississippi
Coastal Waters
* Effective this Thursday morning and afternoon from 745 AM until
200 PM CDT.
* Primary threats include...
A couple tornadoes possible
Isolated damaging wind gusts to 70 mph possible
SUMMARY...Several areas of thunderstorms, moving/expanding inland
from the Gulf, will pose a threat for a couple tornadoes and some
damaging gusts through midday.
The tornado watch area is approximately along and 45 statute miles
north and south of a line from 60 miles northwest of Mobile AL to 20
miles east northeast of Apalachicola FL. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.
&&
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 22030.
...Edwards
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WW 0274 Status Updates
STATUS REPORT ON WW 274
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SSE PNS
TO 35 E GZH.
..DEAN..05/26/22
ATTN...WFO...MOB...TAE...LIX...
STATUS REPORT FOR WT 274
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
FLC005-037-045-059-091-131-133-261840-
FL
. FLORIDA COUNTIES INCLUDED ARE
BAY FRANKLIN GULF
HOLMES OKALOOSA WALTON
WASHINGTON
GMZ635-636-655-750-752-755-261840-
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
WESTERN CHOCTAWHATCHEE BAY
EASTERN CHOCTAWHATCHEE BAY
COASTAL WATERS FROM OKALOOSA-WALTON COUNTY LINE TO PENSACOLA FL
OUT 20 NM
COASTAL WATERS FROM OKALOOSA-WALTON COUNTY LINE TO MEXICO BEACH
OUT 20 NM
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MD 0927 CONCERNING TORNADO WATCH 274... FOR FLORIDA PANHANDLE
Mesoscale Discussion 0927
NWS Storm Prediction Center Norman OK
0159 PM CDT Thu May 26 2022
Areas affected...Florida Panhandle
Concerning...Tornado Watch 274...
Valid 261859Z - 262100Z
The severe weather threat for Tornado Watch 274 continues.
SUMMARY...The threat for localized damaging wind gusts and/or a
brief tornado may continue into late afternoon.
DISCUSSION...Persistent convection has evolved into two north-south
oriented clusters from the northeast Gulf of Mexico into the FL
Panhandle. Extensive cloud cover continues to inhibit heating across
inland areas, though some modest destabilization has occurred near
the coast immediately downstream of both ongoing clusters.
Generally unidirectional southerly flow is noted in the KTLH VWP in
advance of the eastern cluster, so favorable low-level shear will
generally be confined to areas near the outflow-reinforced
baroclinic zone where surface winds have more of an easterly
component. Somewhat stronger southwesterly flow aloft is noted on
the KEVX VWP, upstream of the western cluster. This may allow for
somewhat greater large-scale organization with this cluster, though
the storms with stronger low/midlevel rotation may tend to remain
just offshore. In general, the threat for isolated damaging wind or
a brief tornado will continue near the coast, but likely remain
relatively limited in magnitude. WW 274 has been locally extended
until 21Z to cover any remaining threat.
..Dean.. 05/26/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...
LAT...LON 29238517 29438623 30298621 30738619 30758524 30298370
29418404 29238517
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MD 0926 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHEAST GA...UPSTATE SC...WESTERN NC
Mesoscale Discussion 0926
NWS Storm Prediction Center Norman OK
0125 PM CDT Thu May 26 2022
Areas affected...Northeast GA...Upstate SC...Western NC
Concerning...Severe potential...Watch possible
Valid 261825Z - 262030Z
Probability of Watch Issuance...40 percent
SUMMARY...A threat for locally damaging wind and a tornado or two
will evolve with time this afternoon, as thunderstorms increase in
coverage. The need for a watch is uncertain at this time.
DISCUSSION...Thunderstorms have recently intensified across
northeast GA into upstate SC, near and south of a warm front that is
slowly lifting northward toward western NC. Midlevel lapse rates are
generally weak across this region, but diurnal heating and rich
low-level moisture are supporting MLCAPE of 500-1000 J/kg along and
south of the warm front. Continued heating/destabilization and
negligible MLCINH should contribute to increasing storm coverage
with time, both near the warm front and southward across the warm
sector.
Effective shear currently around 30 kt is only marginally favorable
for storm organization, but this may gradually increase with time
this afternoon, as stronger midlevel flow moves over the region in
advance of the deep-layer cyclone moving across southern MO.
Organized storm clusters and perhaps a couple of supercells will be
possible later this afternoon as storms mature.
In addition to the threat for locally damaging wind gusts and
isolated marginal hail, a brief tornado or two will be possible near
the warm front, where low-level shear will be somewhat enhanced. The
tendency for storms to rather quickly traverse the frontal zone may
tend to limit the tornado threat to some extent, however. The need
for watch issuance is uncertain, but remains possible depending on
observational and storm intensity trends through the afternoon.
..Dean/Hart.. 05/26/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CAE...GSP...FFC...
LAT...LON 35418102 35208079 34308112 33658161 33668268 33788323
34828320 35248271 35428193 35538120 35418102
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1054 AM CDT Thu May 26 2022
Valid 261630Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
MISSISSIPPI...OHIO...AND TENNESSEE VALLEYS...AND OVER PORTIONS OF
THE INTERIOR NORTHWEST....
...SUMMARY...
Isolated to widely scattered severe thunderstorms are possible over
parts of the inland Northwest, and from Mid Mississippi and Ohio
Valley region to the east-central Gulf Coast and southern
Appalachians.
...IL/IN...
A deep upper low will track slowly northeastward across MO today.
The main surface cold front associated with this low extends roughly
along the MS River from northeast MO into southern IL. Considerable
low-level moisture is present ahead of the front across parts of
IL/IN, where relatively strong daytime heating will take place.
Given the cool temperatures aloft and steep lapse rates, scattered
thunderstorms will develop by early afternoon and track northward.
The strongest cells will pose a risk of hail and damaging wind
gusts. Please refer to MCD #923 for more details.
...KY/TN into OH...
The mid-level jet max associated with the aforementioned upper low
extends from AR into KY/TN. Heating will be slow in the area along
the cold front over middle TN and central KY, but dewpoints in the
mid 60s and temperatures slowly warming through the 70s will yield
sufficient CAPE for thunderstorms by mid-afternoon. Relatively
strong low and deep layer shear profiles will promote organized
storm structures including bowing structures and supercells.
Damaging winds appear to be the main threat, along with a few
tornadoes. This activity will move into eastern KY and southern OH
this evening before encountering a more stable air mass and
weakening.
...AL/GA/FL...
Isolated supercells have been occurring off the AL/FL coast this
morning. Other storms are expected through the day along/ahead of
the cold front over western AL. Extensive cloud cover across the
region will limit heating/destabilization. Nevertheless, the
strongest cells in this area will pose a risk of locally damaging
wind gusts and perhaps a tornado.
...OR/ID...
A progressive shortwave trough is approaching the OR coast. Lift
ahead of this trough, coupled with full sunshine and surface
dewpoints in the 40s to lower 50s will result in scattered afternoon
thunderstorms from northeast OR into ID. Hail and locally damaging
wind gusts may occur in the strongest cells late this afternoon and
evening.
..Hart/Squitieri.. 05/26/2022
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 PM CDT Thu May 26 2022
Valid 271200Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CAROLINAS INTO THE MID-ATLANTIC...
...SUMMARY...
Scattered severe thunderstorms may occur Friday from the Carolinas
northward into parts of the Mid-Atlantic. Damaging wind gusts and a
few tornadoes should be the primary threats.
...Synopsis...
A mid/upper-level low will progress eastward from the OH Valley
across the Mid-Atlantic and Northeast on Friday. Large-scale upper
ridging will be maintained over much of the Rockies and Plains,
while a couple of low-amplitude shortwave troughs move across the
Pacific Northwest into the northern Rockies and adjacent High Plains
through the day. At the surface, an elongated area of low pressure
extending from the Great Lakes into Quebec should develop slowly
east-northeastward through the period in tandem with the upper low,
while a cold front will move eastward over much of the East Coast.
...Carolinas into the Mid-Atlantic...
Although mid-level lapse rates are expected to remain generally
poor, rich low-level moisture characterized by mid 60s to low 70s
surface dewpoints will likely be in place ahead of the cold front.
Even modest diurnal heating should contribute to MLCAPE generally
ranging from 500-1500 J/kg, with somewhat greater instability
forecast from parts of MD/VA southward into the Carolinas. Enhanced
low/mid-level south-southwesterly flow associated with the upper low
is expected to be in place from the Carolinas northward over much of
the eastern Mid-Atlantic states ahead of the front. Deep-layer shear
of 35-50+ kt will easily support thunderstorm organization, with a
mix of multicells and supercells possible.
Thunderstorms that will probably be ongoing at the start of the
period Friday morning should gradually increase in coverage and
intensity along/ahead of the front from late Friday morning through
the afternoon. With a large southerly component to the low/mid-level
winds, convection should tend to grow upscale with time into small
bowing clusters as individual updrafts interact with each other. It
appears that scattered damaging winds will probably be the main
threat as thunderstorms spread east-northeastward through the
afternoon and early evening given the messy and mainly multicellular
mode. But, enough low-level shear should also be present in
association with a 30-40 kt southerly low-level jet to support a
risk for a few tornadoes with any embedded supercells, particularly
from central NC into VA/MD/DE, southeastern PA, and NJ Friday
afternoon. Isolated hail may also occur with the strongest updrafts.
The northern extent of the appreciable severe in NY and the
Northeast will be heavily dependent on diurnal heating, the degree
of which remains highly uncertain.
...Montana/Wyoming into the Western Dakotas...
An area of low pressure should develop Friday afternoon over the
western Dakotas as a subtle shortwave trough overspreads the
northern Rockies and High Plains. Initially high-based thunderstorms
that form over the higher terrain of MT/WY should quickly move
eastward into a weakly unstable airmass given limited low-level
moisture. Still, the boundary layer is expected to become very well
mixed by Friday afternoon across the High Plains as diurnal heating
occurs, and isolated strong to severe wind gusts appear possible
with this convection. A few instances of severe hail may also occur
with any robust thunderstorm that can be sustained, as deep-layer
shear appears sufficiently strong for a supercell.
..Gleason.. 05/26/2022
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1104 AM CDT Thu May 26 2022
Valid 261700Z - 271200Z
Only minor modifications were made to the ongoing forecast based on
current guidance. Widely scattered virga showers with gusty outflow
winds are possible in central/northern Nevada. Thermodynamic
profiles remain marginally supportive of a few lightning flashes
across the region. With most area fuels still only marginally dry,
particularly the larger fuels, ignition efficiency from any
lightning activity is expected to be low.
..Wendt.. 05/26/2022
.PREV DISCUSSION... /ISSUED 0107 AM CDT Thu May 26 2022/
...Synopsis...
Elevated fire weather concerns remain likely this afternoon across
northwestern to southern Nevada. Early-morning water vapor imagery
reveals an upper-level wave approaching the Pacific Northwest.
Surface pressure falls across the northern Great Basin will induce
south to southwesterly winds off the Sierra Nevada and lower CO
River Valley. Sustained winds between 15 to 20 mph are expected by
early afternoon based on ensemble guidance. However, deep
boundary-layer mixing will support frequent wind gusts between 25-35
mph, especially across central to southern NV where nearly all
solutions show the strongest low-level mass response. Downslope
effects, combined with antecedent dry conditions and diurnal
warming, will support RH reductions into the 10-15% range across
much of the region. Consequently, elevated (to briefly critical)
fire weather conditions appear likely, including across far western
NV where several lightning strikes were noted Wednesday afternoon.
...Dry Thunderstorms...
The approaching upper low will also support the potential for
isolated to scattered thunderstorms by late afternoon across the
Pacific Northwest and parts of the northern Great Basin. Observed 00
UTC soundings show an increase in column precipitable water over the
region, but values remain near 0.3 to 0.5 inches. Continued
moistening is expected, but PWATs will likely remain near 0.5 to
0.75 across NV and will support a dry-lightning threat. While the
probability for thunderstorms is highest across portions of OR, WA,
and ID, a few dry thunderstorms are possible across central to
northern NV. An isolated dry-thunderstorm risk area is introduced
where confidence in thunderstorms overlapping with critically dry
fuels is highest.
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0227 PM CDT Thu May 26 2022
Valid 271200Z - 281200Z
...CRITICAL FIRE WEATHER AREA FOR PARTS OF SOUTHERN NEVADA INTO
SOUTHWESTERN UTAH...
Critical fire weather conditions appear more likely just ahead of a
southeastward moving surface boundary. Parts of southern Nevada and
southwestern Utah have greater potential for a few hours of
sustained 20+ mph winds. Elsewhere, elevated to locally critical
conditions are still expected across a broad area of the Great Basin
and Southwest. See the previous discussion for details.
..Wendt.. 05/26/2022
.PREV DISCUSSION... /ISSUED 0149 AM CDT Thu May 26 2022/
...Synopsis...
Increasing west to southwest winds across parts of the southern
Great Basin, Southwest, and Four Corners will lead to a broad swath
of fire weather concerns Friday afternoon. The upper-level wave
currently approaching the Pacific Northwest is forecast to translate
into the northern Rockies by late Friday. Falling heights aloft will
support modest surface pressure falls over the inter-mountain West,
resulting in a broad low-level mass response from the southern Great
Basin into the Four Corners and Southwest. Ensemble guidance and
deterministic solutions generally suggest that 15-20 mph winds will
be common across this region. Drier/windier solutions indicate that
areas of 20-25 mph winds are possible, but considerable spread in
deterministic solutions introduces uncertainty regarding the exact
placement and coverage of the strongest winds. Strong mid and
upper-level winds will largely be displaced to the north of the
region, which further limits confidence on where the windiest
corridors will be established within the risk area.
Nonetheless, dry conditions will prevail with 10-15% RH values
expected by late afternoon. Widespread elevated conditions are
likely, and a few corridors of critical conditions are possible.
Similar wind/RH conditions are possible across much of the southern
High Plains as well, but widespread rainfall over the past few days
has mitigated fuel status for the time being. Fuel trends will be
monitored for a possible expansion, but Friday's warm/dry conditions
will likely begin the drying process for most locations as
temperatures rebound into the 90s.
...Please see www.spc.noaa.gov/fire for graphic product...
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