SPC Severe Thunderstorm Watch 124

WW 124 SEVERE TSTM CO KS NE OK TX 271910Z - 280200Z
      
WW 0124 Image

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 124
NWS Storm Prediction Center Norman OK
110 PM MDT Sun May 27 2018

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Eastern Colorado
  Western Kansas
  Southwest Nebraska
  Oklahoma Panhandle
  Northern Texas Panhandle

* Effective this Sunday afternoon and evening from 110 PM until
  800 PM MDT.

* Primary threats include...
  Scattered damaging winds likely with isolated significant gusts
    to 75 mph possible
  Scattered large hail likely with isolated very large hail events
    to 2.5 inches in diameter possible
  A tornado or two possible

SUMMARY...Thunderstorms will become numerous across eastern Colorado
this afternoon, spreading eastward into western Kansas early this
evening.  Other isolated storms will form southward into the Texas
Panhandle.  Large hail and damaging winds are expected with the
strongest cells.  An isolated tornado or two cannot be ruled out.

The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 55 miles north of Akron
CO to 35 miles east of Amarillo TX. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU4).

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 123...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
22030.

...Hart

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SPC Severe Thunderstorm Watch 123

WW 123 SEVERE TSTM NE WY 271805Z - 280200Z
      
WW 0123 Image

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 123
NWS Storm Prediction Center Norman OK
1205 PM MDT Sun May 27 2018

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Western Nebraska
  Southern and Central Wyoming

* Effective this Sunday afternoon and evening from 1205 PM until
  800 PM MDT.

* Primary threats include...
  Scattered large hail likely with isolated very large hail events
    to 2 inches in diameter possible
  Scattered damaging wind gusts to 70 mph likely
  A tornado or two possible

SUMMARY...Thunderstorms are expected to develop across southern
Wyoming and spread northward across the watch area this afternoon. 
The strongest cells will be capable of large hail and damaging wind
gusts.  Any isolated and persistent storm could also pose a risk of
a tornado.

The severe thunderstorm watch area is approximately along and 75
statute miles north and south of a line from 50 miles northwest of
Rawlins WY to 10 miles southeast of Alliance NE. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

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.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 450. Mean storm motion vector
20030.

...Hart

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SPC Severe Thunderstorm Watch 124 Status Reports

WW 0124 Status Updates
      
WW 0124 Status Image

STATUS REPORT ON WW 77

THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.

..BENTLEY..05/04/18

ATTN...WFO...BOX...ALY...GYX...BGM...CTP...


STATUS REPORT FOR WS 77 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

CTC003-005-050040-

CT 
.    CONNECTICUT COUNTIES INCLUDED ARE

HARTFORD             LITCHFIELD          


MAC003-011-013-015-050040-

MA 
.    MASSACHUSETTS COUNTIES INCLUDED ARE

BERKSHIRE            FRANKLIN            HAMPDEN             
HAMPSHIRE            


NHC005-011-013-019-050040-

NH 
.    NEW HAMPSHIRE COUNTIES INCLUDED ARE

CHESHIRE             HILLSBOROUGH        MERRIMACK           
SULLIVAN             


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SPC Severe Thunderstorm Watch 123 Status Reports

WW 0123 Status Updates
      
WW 0123 Status Image

STATUS REPORT ON WW 72

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SE BIE TO
20 NNW FNB TO 5 NNW SDA TO 30 ESE OMA.

FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0342.

..PETERS..05/03/18

ATTN...WFO...DMX...OAX...EAX...TOP...


STATUS REPORT FOR WS 72 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

IAC001-003-009-029-039-049-053-077-099-117-121-125-137-145-153-
159-173-175-181-185-040040-

IA 
.    IOWA COUNTIES INCLUDED ARE

ADAIR                ADAMS               AUDUBON             
CASS                 CLARKE              DALLAS              
DECATUR              GUTHRIE             JASPER              
LUCAS                MADISON             MARION              
MONTGOMERY           PAGE                POLK                
RINGGOLD             TAYLOR              UNION               
WARREN               WAYNE               


KSC005-013-043-061-085-087-117-127-131-149-161-177-197-040040-

KS 
.    KANSAS COUNTIES INCLUDED ARE

ATCHISON             BROWN               DONIPHAN            
GEARY                JACKSON             JEFFERSON           
MARSHALL             MORRIS              NEMAHA              
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SPC MD 541

MD 0541 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF MICHIGAN
        
MD 0541 Image

Mesoscale Discussion 0541
NWS Storm Prediction Center Norman OK
0212 PM CDT Sun May 27 2018

Areas affected...Portions of Michigan

Concerning...Severe potential...Watch unlikely 

Valid 271912Z - 272145Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms will continue to increase in coverage this
afternoon with an isolated severe hail and damaging wind threat
possible in the strongest storms. A WW issuance is unlikely.

DISCUSSION...Visible satellite imagery and NLDN lightning data at
1900 UTC show that thunderstorms are beginning to form over portions
of north-central Michigan as a weak mid-level shortwave trough
approaches. These storms are forming in an environment characterized
by strong heating (e.g., MLCAPE values around 1000-2000 J/kg) and
effective bulk shear values of 20-30 knots (greatest near Lake
Huron). Storms that move through this environment will be capable of
producing at least isolated instances of severe hail and damaging
wind gusts as they move southeastward. Any storms should gradually
weaken later this evening as the boundary layer stabilizes with the
onset of nocturnal cooling. At this time, the coverage of severe
threats appears too low for a WW issuance.

..Elliott/Hart.. 05/27/2018

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

ATTN...WFO...DTX...APX...GRR...

LAT...LON   44168505 44558450 44908393 45088359 45138332 45148306
            44538279 44238270 43848267 43648267 43378271 43208285
            42938306 42788333 42728375 42738417 42848461 43128504
            43418535 43808555 44168505 

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SPC MD 540

MD 0540 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR EASTERN COLORADO INTO WESTERN KANSAS...AND THE OKLAHOMA AND TEXAS PANHANDLES
MD 0540 Image


Mesoscale Discussion 0540
NWS Storm Prediction Center Norman OK
0138 PM CDT Sun May 27 2018

Areas affected...Eastern Colorado into western Kansas...and the
Oklahoma and Texas Panhandles

Concerning...Severe potential...Watch likely 

Valid 271838Z - 272115Z

Probability of Watch Issuance...95 percent

SUMMARY...Large hail and damaging wind are quite likely this
afternoon across eastern Colorado into western Kansas, and southward
into the Texas Panhandle.

DISCUSSION...Strong heating continues across the High Plains near a
lee trough, and in advance of a belt of stronger midlevel flow with
the upper trough to the west. Low-level winds will continue to
strengthen and back to southeasterly, enhancing the westward
transport of moisture and gradual upslope. Forecast soundings show
very steep lapse rates developing through a deep layer, and this
combined with peak heating will aid updraft acceleration. While flow
aloft is not particularly strong, the veering of the winds with
height is creating long hodographs clearly supportive of severe
storms. A mixed storm mode of cells and possible squall line is
expected, with capable of damaging wind-driven hail. Capping will
become a concern into the evening, with an abrupt decrease in
intensity expected around the longitude of 100 W.

..Jewell/Hart.. 05/27/2018

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

ATTN...WFO...LBF...DDC...GLD...AMA...PUB...BOU...

LAT...LON   39820375 39080342 38330308 37180266 36330248 35730234
            35120199 34890174 34890164 34930121 35330072 36220024
            37070007 37710012 39060068 39820139 40710246 40780303
            40460351 39820375 

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SPC MD 539

MD 0539 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR MUCH OF CENTRAL INTO EASTERN WYOMING
MD 0539 Image


Mesoscale Discussion 0539
NWS Storm Prediction Center Norman OK
1236 PM CDT Sun May 27 2018

Areas affected...Much of central into eastern Wyoming

Concerning...Severe potential...Watch likely 

Valid 271736Z - 272000Z

Probability of Watch Issuance...80 percent

SUMMARY...Storms should increase in coverage and intensity through
the afternoon, with damaging wind and/or hail possible.

DISCUSSION...A moist air mass has spread into central WY due to east
and northeast surface winds, resulting in an unstable air mass.
Heating will persist as well, with MUCAPE in excess of 2000 J/kg
into eastern WY where moisture is most substantial. Meanwhile, lapse
rates are steep through a deep layer courtesy of the upper trough.
Although mid and upper flow is not strong, these southerlies atop
low-level northeasterlies is elongating hodographs and will be
supportive of organized storms over the entire region. Storms are
already forming near the Wind River mountains due to upslope flow,
and these storms will gradually expand southeastward toward a
developing CU field near the south central mountains of WY. Damaging
winds will be possible given the expected elongated/somewhat linear
storm mode, but embedded cells, and/or any isolated cells that may
form will be capable of large hail given the cold air aloft.

..Jewell/Hart.. 05/27/2018

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

ATTN...WFO...UNR...CYS...RIW...

LAT...LON   42280824 43250919 43690920 44340868 44170629 43950522
            43510457 42680432 41610465 41210515 41110566 41300642
            41600730 42280824 

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SPC MD 538

MD 0538 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL/NORTHERN VIRGINIA...CENTRAL/SOUTHERN MARYLAND...AND EASTERN WEST VIRGINIA
MD 0538 Image


Mesoscale Discussion 0538
NWS Storm Prediction Center Norman OK
1229 PM CDT Sun May 27 2018

Areas affected...Portions of central/northern
Virginia...central/southern Maryland...and Eastern West Virginia

Concerning...Severe potential...Watch unlikely 

Valid 271729Z - 272000Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms will increase in coverage this afternoon
with locally severe hail and damaging wind gusts possible. A WW
issuance is unlikely.

DISCUSSION...Latest visible satellite and radar imagery from 1730Z
shows thunderstorms developing over the higher terrain of the
Appalachians/Blue Ridge Mountains as well as along a backdoor cold
front across northern/northeastern Maryland. Ample insolation
through the morning and early afternoon coupled with a moist
boundary layer (e.g., surface dew points in the 70s) has allowed
MLCAPE values to climb to around 1500-2000 J/kg. While mid-level
flow is relatively modest (e.g., 30 knots at 500 mb), the presence
of a nearby weak mid-level trough will foster effective bulk shear
values of 20-35 knots (greatest over Maryland). While CAM guidance
suggests messy storm modes, CAPE/Shear parameter space will support
at least transient storm organization with the potential for locally
severe hail and damaging wind gusts in the strongest storms.
However, these threats are currently expected to remain too isolated
for a WW issuance.

..Elliott/Hart.. 05/27/2018

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

ATTN...WFO...PHI...AKQ...LWX...RNK...

LAT...LON   37727964 38287934 38887895 39277867 39507834 39647787
            39657731 39677688 39657622 39117613 38857606 38477602
            38117602 37817611 37517624 37337657 37147866 37727964 

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SPC MD 537

MD 0537 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PART OF CENTRAL AND WESTERN FLORIDA
MD 0537 Image


Mesoscale Discussion 0537
NWS Storm Prediction Center Norman OK
1156 AM CDT Sun May 27 2018

Areas affected...Part of central and western Florida

Concerning...Severe potential...Watch unlikely 

Valid 271656Z - 271930Z

Probability of Watch Issuance...20 percent

SUMMARY...A chance of rotating storms including the threat of a
brief tornado may exist over the next few hours across west-central
to central Florida.

DISCUSSION...Current objective analysis as well as the TBW VAD shows
0-1 SRH of 200-250 m2/s2 centered near Tampa as a line of storms
forms to the south. Visible imagery also shows areas of heating, and
further development is also possible. These storms may acquire
rotation as they become more established and shift north into the
greater low-level shear zone. With time, this zone of shear will
also depart the area. Therefore, the best chance of a brief tornado
appears to be over the next few hours. However, the threat is
unlikely to be great enough for a watch.

..Jewell/Hart.. 05/27/2018

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

ATTN...WFO...MFL...MLB...TBW...JAX...

LAT...LON   27138255 27878292 28348279 28858273 29098281 29138241
            29048208 28988197 28578156 27728116 27128100 26598112
            26488143 26678197 26888236 27138255 

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SPC May 27, 2018 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1125 AM CDT Sun May 27 2018

Valid 271630Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
FLORIDA...

...SUMMARY...
Severe storms are possible later today into this evening primarily
from the northern through southern High Plains. A modest threat for
a few tornadoes will also exist across the Florida Peninsula.

...WY/SD/NE...
A large upper low is positioned over NV today, with multiple
shortwave troughs rotating around the trough into the central
Rockies.  Models are very consistent in the development of a band of
thunderstorms this afternoon across southern WY arcing into
northeast CO.  These storms are expected to spread northward through
the evening into parts of western SD and western NE.  Easterly
low-level winds and favorable thermodynamics may support a few
supercells in this regime, but it appears likely that congealing
outflows will lead to multiple bowing line segments across the risk
area.  Damaging winds and hail are the main threats, with isolated
tornadoes possible early in the convective evolution.

...West TX into eastern CO/western KS...
Mid level height falls are spreading into the central High Plains,
where strong heating and rapid destabilization is occurring.  This
will lead to scattered thunderstorms throughout the region later
today.  Deep boundary-layer mixing and steep low-level lapse rates
will promote strong outflows in the storms, with damaging winds and
hail being the main threats.

...FL and coastal GA/SC...
Relatively strong low-level winds are present today across most of
the FL peninsula, although veering/weakening is occurring across
southwest FL behind Alberto.  Visible satellite shows broken clouds
across the region, providing some potential for daytime
heating/destabilization.  This may lead to a few rotating cells
later this afternoon with a risk of isolated tornadoes.  Based on
12z model solutions, am extending low tornado probabilities into
coastal sections of GA/SC for late tonight.

...PA/MD/VA...
Visible satellite imagery shows a pocket of strong heating occurring
over parts of southern PA into northern VA.  Meanwhile, a back-door
cold front is surging southward into the region.  Given the
moist/unstable air mass in this region, have added a MRGL risk for
afternoon thunderstorms spreading east-southeastward as an weak
upper trough grazes the area.  Locally gusty winds and hail are
possible with the strongest cells.

...Eastern Lower MI...
12z CAM solutions are consistent that a cluster of thunderstorms
will form this afternoon over southeast Lower MI ahead of a weak
shortwave trough and in region of strong heating.  Forecast
soundings show considerable CAPE and sufficient vertical shear for
hail and gusty winds in the strongest cells.

..Hart/Elliott.. 05/27/2018

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SPC May 27, 2018 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook
      
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1224 PM CDT Sun May 27 2018

Valid 281200Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE GREAT PLAINS...

...SUMMARY...
Severe thunderstorms with isolated large hail, wind damage and
perhaps a tornado threat are expected across parts of the Great
Plains.  A couple of brief tornadoes will also be possible in the
Southeast, in conjunction with Alberto.

...Great Plains...
An upper-level low will move slowly northeastward into the northern
Rockies on Monday as an upper-level ridge amplifies across the upper
Mississippi Valley. At the surface, a trough will deepen across
eastern Colorado as a slow moving front moves across northern parts
of the central Plains. Surface dewpoints to the southeast of the
front should be in the 55 to 60 F range allowing for moderate
destabilization across parts of the central plains by afternoon.
Convection is forecast to initiate on the western edge of the
stronger instability during the mid to late afternoon from
east-central Colorado northward into eastern Wyoming. Thunderstorm
development should take place as this convection moves
east-northeastward into the central and northern high Plains during
the late afternoon and early evening. Other thunderstorms may also
develop further east across parts of the Dakotas and Nebraska.

NAM and GFS forecast soundings are in reasonable agreement across
the central and northern high Plains during the late afternoon
showing MLCAPE values mostly in the 2000 to 3500 J/kg range across
the moist sector. In addition, low to mid-level lapse rates are
forecast to be quite steep exceeding 8.0 C/km in some areas. This
combined with moderate deep-layer shear will be favorable for
supercells with large hail. The strongest deep-layer shear is
forecast early Monday evening over western Nebraska and northeast
Colorado due to the influence of a strengthening low-level jet. This
area appears to have the strongest potential for tornadoes. Model
forecasts markedly increase convective coverage across the central
Plains during the mid to late evening as a shortwave trough moves
out. As a result, the wind damage potential may increase especially
if storms can consolidate into an organized multicell line segment.

Further south across western Kansas into the Texas Panhandle, 700 mb
temperatures are expected to be above 12 Celsius which will
contribute to a capping inversion. By late afternoon, increasing
low-level convergence around a surface low in southeast Colorado
along with a weakening cap, should allow for isolated convective
initiation. Moderate instability and deep-layer shear combined with
steep low to mid-level lapse rates should be favorable for isolated
large hail and a few strong wind gusts.

...Southeast U.S. and Florida...
The National Hurricane Center is forecasting Subtropical Storm
Alberto to move across the northeast Gulf of Mexico and approach the
coast of the Florida Panhandle around daybreak on Monday. Rainbands
should spread northward across much of the Florida Peninsula into
parts of Georgia and South Carolina during the day. Forecast
soundings from central Florida northward into Georgia show speed
shear and some directional shear in the lowest 3 km AGL suggesting a
tornado threat will be possible with discrete rotating storms. The
greatest potential for tornadoes could exist from the eastern
Florida Panhandle northward into central Georgia where the
combination of instability and low-level shear is forecast to be the
greatest.

...MAXIMUM RISK BY HAZARD...
Tornado:   5%     - Slight
Wind:     15%     - Slight
Hail:     15%     - Slight

..Broyles.. 05/27/2018

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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
1018 AM CDT Sun May 27 2018

Valid 271700Z - 281200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHEAST COLORADO
INTO NORTHEAST NEW MEXICO...

The ongoing forecast is on track and no changes are needed. See
discussion below for more details.

..Leitman.. 05/27/2018

.PREV DISCUSSION... /ISSUED 0158 AM CDT Sun May 27 2018/

...Synopsis...
A short-wave trough moving northward to the east of a closed low
across the Great Basin will increase tropospheric flow across much
of the southern and central Rocky Mountains and the adjacent High
Plains. Although the bulk of the flow will be oriented parallel to
the mountains, enough of a downslope component will exist to
establish a lee trough in the High Plains.

Coincident with the weak lee trough, a low-level thermal ridge will
develop from the central Texas Panhandle northwest toward the Palmer
Divide. To the west of this thermal ridge axis, hot, dry conditions
will combine with the increasing tropospheric flow to result in
surface winds in excess of 20 mph, with higher gusts. Additionally,
afternoon relative humidity should fall into the single digits to
low teens. The result will be critical fire-weather conditions from
northeast New Mexico into south-central Colorado. Surrounding the
critical area, and extending south-southeast toward southeast
Arizona, sustained winds should be in the 15-20 mph range, albeit
rather gusty. As such, elevated fire-weather conditions are likely
here.

...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
0114 PM CDT Sun May 27 2018

Valid 281200Z - 291200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHEAST CO AND
NORTHEAST NEW MEXICO...

Adjustments have been made to the elevated and critical areas based
on latest hi-res model guidance and fuel status information. The
main adjustment has been to trim the eastern edge of the critical
area as fuel conditions may not be as supportive for large fires
across far southeast CO into southwest KS and the western OK/TX
Panhandle. Additionally, latest model forecasts suggest the dryline
will remain near the TX/NM border and southeasterly flow ahead of
this feature will moderate dewpoints. Furthermore, potential for
thunderstorm development will exist in the vicinity of the dryline
and surface low across parts of eastern CO, western KS and the OK/TX
Panhandles(see Day 2 Convective Outlook for severe thunderstorm
potential). These storms are expected to produce wetting rains,
precluding the need for a dry thunderstorm area.

..Leitman.. 05/27/2018

.PREV DISCUSSION... /ISSUED 0158 AM CDT Sun May 27 2018/

...Synopsis...
Closed low over the Great Basin will weaken, open up, and begin to
move east on Monday. To the southeast of the main low/trough,
persistent south-southwest mid-level flow will maintain lee
troughing across the central and southern High Plains, albeit
slightly farther east than previous days. The result will once again
be the overlap of strong, gusty surface winds in excess of 20 mph
and minimum relative humidity in the low teens. As such another day
of critical fire-weather conditions across northeast New Mexico,
southeast Colorado, and the Texas and Oklahoma Panhandles will
occur. Surrounding the critical, elevated fire-weather concerns will
persist, with the duration of winds in excess of 20 mph being the
mitigating factor for higher-end fire-weather concerns.

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

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