SPC Forecast

RSS Mesoscale Discussions from Storm Prediction Center

SPC - No watches are valid as of Thu Feb 22 20:00:03 UTC 2018

No watches are valid as of Thu Feb 22 20:00:03 UTC 2018.


SPC - No MDs are in effect as of Thu Feb 22 20:00:03 UTC 2018

No Mesoscale Discussions are in effect as of Thu Feb 22 20:00:03 UTC 2018.


SPC Feb 22, 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
1023 AM CST Thu Feb 22 2018

Valid 221630Z - 231200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Clusters of elevated thunderstorms will continue through the period
from Texas and Oklahoma to parts of the Mississippi and Ohio Valley
regions.

...Synopsis...
A deep midlevel trough will continue to dig south-southeastward
along the Pacific Coast with an associated low-end thunderstorm
threat, while a downstream shortwave trough ejects northeastward
from the southern High Plains to the Upper Midwest around the
northwest periphery of the southwest Atlantic ridge.  A slow-moving
baroclinic zone will persist from eastern TN/KY to the northwest
Gulf Coast.  The vast majority of the convection this forecast
period will be elevated, rooted above the shallow sloped frontal
surface from the southern Plains to the MS/OH Valleys regions.  Most
of the thunderstorms will be focused in the warm advection zone
preceding the midlevel trough now ejecting northeastward across
TX/OK, though this convection is already progressing away from the
source region of steeper lapse rates/moisture and larger resultant
buoyancy.  Farther east, thunderstorms will be rooted closer to the
surface on the immediate cool side of the slow-moving front from LA
to TN.  The primary source for lift will be warm advection atop the
cool air mass, while vertical shear and ascent should remain weak in
the warm sector.  As such, severe storms appear unlikely.

..Thompson/Gleason.. 02/22/2018

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SPC Feb 22, 2018 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0131 PM CST Thu Feb 22 2018

Valid 222000Z - 231200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Clusters of elevated thunderstorms will continue through the period
from Texas and Oklahoma to parts of the Mississippi and Ohio Valley
regions.

Only minor changes to the TX and CA portions of the general
thunderstorm lines were made. Heating continues across parts of
northern CA, which may yield isolated weak thunderstorms later this
afternoon in association with a shortwave trough with very cold
temperatures aloft. In TX, the west edge of the initial elevated
storm activity is gradually shifting eastward. However, a few storms
are possible later tonight near the Rio Grande, moving into central
TX where warm advection aloft will increase again.

Elsewhere, elevated storms should persist across eastern OK into AR
where lift is strongest. Farther south, surface based instability
does exist south of a retreating front, but lift does not appear
sufficient for any marginal severe threat.

..Jewell.. 02/22/2018

.PREV DISCUSSION... /ISSUED 1023 AM CST Thu Feb 22 2018/

...Synopsis...
A deep midlevel trough will continue to dig south-southeastward
along the Pacific Coast with an associated low-end thunderstorm
threat, while a downstream shortwave trough ejects northeastward
from the southern High Plains to the Upper Midwest around the
northwest periphery of the southwest Atlantic ridge.  A slow-moving
baroclinic zone will persist from eastern TN/KY to the northwest
Gulf Coast.  The vast majority of the convection this forecast
period will be elevated, rooted above the shallow sloped frontal
surface from the southern Plains to the MS/OH Valleys regions.  Most
of the thunderstorms will be focused in the warm advection zone
preceding the midlevel trough now ejecting northeastward across
TX/OK, though this convection is already progressing away from the
source region of steeper lapse rates/moisture and larger resultant
buoyancy.  Farther east, thunderstorms will be rooted closer to the
surface on the immediate cool side of the slow-moving front from LA
to TN.  The primary source for lift will be warm advection atop the
cool air mass, while vertical shear and ascent should remain weak in
the warm sector.  As such, severe storms appear unlikely.

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SPC Feb 22, 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
1131 AM CST Thu Feb 22 2018

Valid 231200Z - 241200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Scattered thunderstorms are expected over much of Texas and
Oklahoma, with a few extending into the Mississippi and Ohio
Valleys. Small hail is possible across parts of northern Texas into
Oklahoma during the day.

...Synopsis...
A southwesterly flow regime aloft will persist from the southern
Plains into the Northeast as an upper trough moves across the
Rockies and into the High Plains by the end of the period.
Meanwhile, and upper ridge will remain intact across the Southeast. 
At the surface, a stalled front from the middle MS Valley into
southeast TX will retreat northward late in the day, with
strengthening southerly wind profiles in anticipation of the
approaching shortwave trough. The result will be a substantial area
of elevated thunderstorms across much of central and northern TX
into OK during the day, wither other activity developing across AR
and MO as well.

...Northern TX into southern OK...
While a cool surface air mass will remain in place, very strong
warm/theta-e advection will occur during the day and into the
evening with southerly 850 mb flow increasing to nearly 50 kt. This
will occur beneath cool mid/upper level profiles, with long
hodographs in the cloud bearing layer. A large area of elevated
thunderstorms will occur across much of northern TX during the late
morning and spreading into OK and toward the Arklatex later in the
day. Some model differences exist as to how much activity will form
and how cellular it may be. However, a marginal hail threat is
possible with the stronger cores. A Marginal Risk may be required in
later outlooks once predictability becomes greater.

..Jewell.. 02/22/2018

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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
0942 AM CST Thu Feb 22 2018

Valid 221700Z - 231200Z

...NO CRITICAL AREAS...

The ongoing forecast is on track, with continued quiescent fire
weather across the Lower 48.

..Cook.. 02/22/2018

.PREV DISCUSSION... /ISSUED 0126 AM CST Thu Feb 22 2018/

...Synopsis...
An upper trough over the western U.S. will deepen and slowly shift
east over the Great Basin today. Downstream, a broad swath of deep
layer southwesterly flow will persist east of the Rockies. Strong
surface high pressure centered over the Great Lakes will track east
toward New England. Gulf moisture will slosh northeast as Wednesday
cold front retreats as a warm front across the lower Ohio Valley
into eastern TX. Fire weather concerns are not expected given
widespread precipitation over the last few days east of the Rockies,
and a general lack of strong surface winds aligning with low RH
values.

...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
0157 PM CST Thu Feb 22 2018

Valid 231200Z - 241200Z

Elevated to locally critical fire weather conditions are possible in
eastern New Mexico and vicinity Friday afternoon.  Areas of gusty
winds (locally exceeding 20-25 mph) will coincide with 15-25% RH
values during the afternoon across the elevated area. 

See the previous discussion below for more information.

..Cook.. 02/22/2018

.PREV DISCUSSION... /ISSUED 0126 AM CST Thu Feb 22 2018/

...Synopsis...
The western upper trough centered over the Great Basin will track
eastward to the southern/central Rockies on Friday. As heights fall,
deep layer southwesterly flow will increase and a weak surface
trough will develop across the southern High Plains. This will lead
to breezy southwest surface winds across much of NM. RH values also
will fall into the 15-25 percent range. This will result in elevated
fire weather potential across the eastern NM Plains into parts of
far southeast CO and southwestern TX. While gusty winds and low RH
will also exist across western and central NM, fuel conditions are
less favorable than further east, limiting fire weather concerns.

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

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