SPC Severe Thunderstorm Watch 260

WW 260 SEVERE TSTM TX 220355Z - 220900Z
      
WW 0260 Image

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 260
NWS Storm Prediction Center Norman OK
1055 PM CDT Sat May 21 2022

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  South and Southeast Texas

* Effective this Saturday night and Sunday morning from 1055 PM
  until 400 AM CDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph possible
  Scattered large hail events to 1.5 inches in diameter possible

SUMMARY...Multiple clusters of strong to severe thunderstorms are
expected to persist south/eastward across south/south-central toward
southeast Texas overnight. Large hail and severe-caliber wind gusts
are possible.

The severe thunderstorm watch area is approximately along and 80
statute miles east and west of a line from 65 miles southwest of
Cotulla TX to 90 miles east northeast of New Braunfels TX. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for 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. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 258...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 600. Mean storm motion vector
29025.

...Guyer

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SPC Severe Thunderstorm Watch 260 Status Reports

WW 0260 Status Updates
      
WW 0260 Status Image

STATUS REPORT ON WW 260

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 WNW COT
TO 15 SW COT TO 20 WSW NIR TO 40 N NIR TO 35 SE CLL.

..KERR..05/22/22

ATTN...WFO...EWX...HGX...CRP...


STATUS REPORT FOR WS 260 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

TXC015-025-089-123-127-175-239-283-285-323-469-479-220840-

TX 
.    TEXAS COUNTIES INCLUDED ARE

AUSTIN               BEE                 COLORADO            
DEWITT               DIMMIT              GOLIAD              
JACKSON              LA SALLE            LAVACA              
MAVERICK             VICTORIA            WEBB                


THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY.  PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.

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SPC MD 867

MD 0867 CONCERNING SEVERE THUNDERSTORM WATCH 260... FOR PARTS OF SOUTHEASTERN TEXAS
MD 0867 Image


Mesoscale Discussion 0867
NWS Storm Prediction Center Norman OK
0209 AM CDT Sun May 22 2022

Areas affected...Parts of southeastern Texas

Concerning...Severe Thunderstorm Watch 260...

Valid 220709Z - 220915Z

The severe weather threat for Severe Thunderstorm Watch 260
continues.

SUMMARY...A few strong wind gusts approaching severe limits are
still possible through 4-6 AM CDT, particularly across the middle
and upper coastal plain.  A new severe weather watch is not
currently anticipated, but trends will continue to be monitored.

DISCUSSION...Embedded within light (around 10 kt) and weakly sheared
deep-layer west-southwesterly mean ambient flow, peak thunderstorm
intensities have generally been slowly diminishing along the leading
edge of southward and eastward advancing convective outflows. 
Inflow is becoming characterized by weaker CAPE with some cooling of
the seasonably moist boundary layer across the coastal plain, but
potential instability does still remain strong (up to 3000 J/kg).  

Given this lingering instability, it might still not be out of the
question that one or two mesoscale convective vortices could become
better defined, with strengthening rear inflow and downdrafts, and
potential for strong surface gusts approaching severe limits,
particularly west and southwest of the Greater Houston area. 
However, it is not clear that this will require a new severe weather
watch.

..Kerr.. 05/22/2022

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

ATTN...WFO...LCH...HGX...CRP...EWX...

LAT...LON   29049763 29289687 30039638 30529532 30799418 29849357
            29459411 28619616 28169750 28399785 29049763 

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SPC May 22, 2022 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1231 AM CDT Sun May 22 2022

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEASTERN UNITED STATES...

...SUMMARY...
Isolated severe storms with wind damage and hail will be possible
across parts of the Northeast on Sunday. A marginal severe threat
may also develop from the Carolina Piedmont to the Gulf Coast
states.

...Northeast...

Upper ridge will flatten across New England Sunday as strong
mid-level flow translates across ON into QC ahead of a short-wave
trough. As a result, large-scale ascent will primarily remain north
of the international border. Even so, in response to the Canadian
short wave, some semblance of a LLJ will evolve ahead of the front
with southwesterly 850mb flow expected to increase to near 40kt
along the Maine/QC border. Latest guidance suggests a weak surface
low will track across southern QC which will encourage the warm
sector to recover a bit across northern ME, ensuring adequate
buoyancy for robust updrafts.

Latest model guidance suggests much of the northeastern US will
experience seasonally strong boundary-layer heating ahead of the
front. Scattered convection should readily develop across the warm
sector in advance of the wind shift. Forecast soundings support
supercells along with organized multicell clusters. 

Early this morning, a substantial amount of convection has
progressed into the TN Valley and there is some indication a weak
disturbance could evolve from the middle TN activity by sunrise. If
so, this feature would progress northeast and likely contribute to
renewed convection over the middle Atlantic later today. At this
time will not extend SLGT Risk into MD/VA to account for this
threat, as this feature may be more readily ascertained by late
morning.

...Lower Latitudes...

A substantial amount of deep convection has evolved and propagated
into the central Gulf Basin. Latest model guidance suggests somewhat
stronger mid-level flow will evolve across the eastern Gulf which
could extend toward the FL Big Bend region. Forecast soundings
exhibit substantial low-level turning and this may contribute to
some weak rotation at times within stronger updrafts.

Extensive frontal convection continues from middle TN-southern
AR-south TX. This activity is expected to propagate southeast toward
the middle/upper TX/southwestern LA coast toward the beginning of
the period. Any daytime robust convection should evolve ahead of
this activity. Gusty winds would be the primary severe threat.

..Darrow/Moore.. 05/22/2022

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SPC May 22, 2022 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook
      
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1236 AM CDT Sun May 22 2022

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
TEXAS...

...SUMMARY...
Isolated wind damage and large hail will be possible across parts of
Texas Monday afternoon and evening.

...Texas...
An upper-level trough will move slowly eastward across the Four
Corners region on Monday, as southwest mid-level flow remains
established from the southern Plains into the lower to mid
Mississippi Valley. Ahead of the trough, a moist and unstable
airmass will be in place over Texas and Louisiana. Southeasterly
flow at the surface will result in moisture advection across much of
Texas. Dewpoints within the moist airmass will range from the 60s F
in the low Rolling Plains to the mid 70s F along the Texas coast.
The strongest instability in the afternoon will likely develop in
areas that remain convectively undisturbed. Model forecasts at this
time have a wide range of outcomes concerning the forecast
instability distribution. The current thinking takes an ensemble
approach, with moderate instability developing by afternoon from the
Texas Coastal Plains northwestward into the Texas Hill Country.
Thunderstorm development during the mid to late afternoon would most
likely take place on the western and northern edge of moderate
instability from near Del Rio to Abilene. Storm coverage should
increase in the late afternoon, with a convective complex moving
eastward across the Texas Hill Country.

NAM forecast soundings near San Antonio late Monday afternoon have
MLCAPE near 2000 J/kg, with 0-3 km lapse rates near 7.5 C/km. This
thermodynamic environment along with 0-6 km shear in the 30 to 35
knot range would be sufficient for severe-thunderstorm development.
Most of the storms should remain multicellular, with a threat for
wind damage and hail. Although the supercell threat will be
conditional, a few storms could become supercellular, mainly in the
late afternoon when instability is maximized. A small slight has
been added in the southern and western Texas Hill Country, where
model forecasts suggest the potential for moderate instability,
moderate shear and convective development is maximized.

..Broyles.. 05/22/2022

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SPC May 22, 2022 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook
      
Day 3 Outlook Image
Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0217 AM CDT Sun May 22 2022

Valid 241200Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
CENTRAL AND EAST TEXAS...

...SUMMARY...
Isolated severe storms with wind damage and large hail will be
possible on Tuesday across parts of the southern Plains and
Arklatex.

...Southern Plains/Arklatex...
An upper-level trough is forecast to move eastward into the southern
High Plains on Tuesday. At the surface, a cold front is forecast to
advance southward across the southern Plains. Ahead of the front, a
moist airmass will be in place, with surface dewpoints mostly in the
60s F. A complex of thunderstorms is forecast to move eastward
across parts of east Texas and the Texas Coastal Plain early in the
period. If this complex materializes, it will have an impact on
destabilization later in the day. Model forecasts suggest that
moderate instability will develop by afternoon to the west of this
complex from southwest Texas northeastward into the Texas Hill
Country. Surface-based thunderstorm development appears most likely
on the northern edge of the moderate instability across parts of
central and north Texas. Additional storms may form on the cold
front. In addition to moderate instability, forecast soundings in
the eastern parts of the Texas Hill Country have 0-6 km shear in the
30 to 40 knot range and show steep low to mid-level lapse rates.
This should be favorable for severe storms with wind-damage and hail
potential. If an MCS can become organized, then the severe threat
could persist into the early to mid evening.

..Broyles.. 05/22/2022

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SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
          
Day 1 Fire Weather Outlook Image
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1249 AM CDT Sun May 22 2022

Valid 221200Z - 231200Z

...CRITICAL FIRE WEATHER AREA FOR EASTERN ARIZONA TO WESTERN NEW
MEXICO...
...CRITICAL FIRE WEATHER AREA FOR SOUTHERN UTAH...

...Synopsis...
Fire weather concerns are expected today across portions of the
Southwest and Four Corners region. Early-morning water-vapor imagery
reveals a weak upper-level disturbance approaching Baja California.
This feature will meander east through the day, resulting in modest
surface pressure falls across the greater Four Corner region. The
tightening pressure gradient at the surface will result in
strengthening winds over a region with low relative humidity and dry
fuels.

...Eastern Arizona to New Mexico...
Latest guidance continues to show reasonably high probability of
sustained 20-25 mph winds across parts of eastern AZ into western NM
this afternoon. This region has seen slight drying over the past 24
hours with dewpoints largely in the low to mid 20s. Little to no
moisture recovery into the region will support another day of
widespread sub-15% RH. Recent fuel analyses as well as fire activity
over the past 24 hours indicate fuels are very receptive.
Consequently, elevated to critical fire weather conditions are
expected across much of eastern AZ and western NM. Within the
Critical risk area, brief and localized high-end critical conditions
are possible as RH falls into the single digits with occasional wind
gusts between 25-30 mph.

...Southern Nevada to eastern Utah...
Southern NV will largely be on the periphery of the stronger
low-level mass response; however, ensemble guidance has shown
reasonably good agreement in sustained 15-20 mph winds this
afternoon with RH values falling to 10-15%. Ensemble guidance also
hints at an increasing probability for sustained 20 mph winds across
southern to southeastern UT. Fuels through this region are receptive
based on latest ERC analyses, warranting the introduction of a small
Critical risk area where confidence in the overlap of dry fuels, 20+
mph winds and sub-15% RH is highest.

...Southern to central High Plains...
A dry return flow regime is expected across the OK/TX Panhandles
into eastern CO/western KS this afternoon. The recent frontal
intrusion will limit any moisture return into the region this
afternoon as surface winds increase to 15-20 mph. However, cooler
temperatures will generally limit RH reductions with only a few
warmer/drier solutions hinting at critical RH. Additionally, recent
precipitation across eastern CO will limit the spatial extent of the
concern. While localized elevated conditions are possible, these
factors preclude highlights at this time.

...Sacramento Valley...
Northerly down-valley flow is expected this afternoon, which will
help adiabatically dry and warm conditions through the Sacramento
Valley with RH values falling to near 15% by mid afternoon. However,
winds are expected to generally be weak with ensemble consensus
suggesting 10-15 mph winds are likely. A few locations may observe
periodic elevated conditions, but the overall threat remains too
limited for highlights.

..Moore.. 05/22/2022

...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 Image
Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0150 AM CDT Sun May 22 2022

Valid 231200Z - 241200Z

...Synopsis...
The surface low that is forecast to develop over the Four Corners
region on Sunday will shift into the southern/central High Plains by
Monday afternoon. This will strengthen westerly winds across the
Southwest, resulting in another day of fire weather concerns for a
region with receptive fuels. A few dry thunderstorms are possible
across southeast Colorado/eastern New Mexico Monday afternoon, but
overall confidence in the propensity for dry lightning strikes is
low.

...Southwest...
Fire activity in recent days verifies the critically dry fuels
depicted in fuel guidance across eastern AZ into NM. Dry conditions
already in place across this region will linger given little to no
moisture recovery over the next 48 hours. As the pressure gradient
tightens through the day Monday, sustained winds should increase to
15-20 mph, as suggested by ensemble guidance. While elevated
conditions appear likely, a few solutions hint that winds up to
20-25 mph (with gusts up to 35 mph) are possible across portions of
southwest to central NM. However, such conditions will most likely
occur in mainly desert terrain where fuel loading is low, and this
scenario is depicted by mainly warmer/drier members. Trends in
guidance and observations will be monitored, and a Critical risk
area may be needed for portions of southern NM if confidence in
widespread critical conditions increases.

...Dry Thunderstorms...
Thunderstorm initiation is likely late Monday afternoon along the
southern Rockies from southeast CO into eastern NM within an upslope
flow regime. Forecast soundings suggest that early convective
activity may occur on the fringe of deeper boundary-layer moisture
where precipitable-water values are forecast to be near 0.5 to 0.75
inches. This suggests that initial thunderstorms may pose a threat
for a few dry lightning strikes. However, storm motions to the east
at around 30 knots should promote quick intensification within the
richer moisture, yielding increasing rainfall rates. This may limit
the duration and coverage of the dry-lightning threat, and precludes
any dry-lightning highlights at this time.

..Moore.. 05/22/2022

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

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