SPC - No watches are valid as of Thu Jan 17 20:37:02 UTC 2019

No watches are valid as of Thu Jan 17 20:37:02 UTC 2019.


No Mesoscale Discussions are in effect as of Thu Jan 17 20:37:02 UTC 2019.

SPC Jan 17, 2019 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
1029 AM CST Thu Jan 17 2019

Valid 171630Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS EASTERN
NV/WESTERN UT...

...SUMMARY...
Strong to isolated severe wind gusts will be possible with isolated
thunderstorms across parts of eastern Nevada into western Utah
during the late afternoon and early evening.

...Eastern NV and Western UT...
Guidance differs greatly with the degree and eastern extent of
boundary-layer heating with the NAM substantially cooler than the
RAP, given a pervasive swath of ongoing cloudiness. However,
mid-level drying yielding clearing is evident in satellite imagery
across western NV and this should shift eastward into the afternoon.
In conjunction with mid-level cold-air advection, the setup should
foster increasing destabilization during the afternoon via delayed
boundary-layer heating and lapse rates aloft becoming very steep. 

Mid-level DCVA associated with the portion of the shortwave trough
shifting from northern CA into the Great Basin and convergence along
a cold front should yield a broken band of showers with embedded
thunderstorms by late afternoon from the NV/UT/ID border area
south-southwest into east-central NV. 30-40 kt effective shear could
support modestly organized convective structures. Where inverted-v
thermodynamic profiles can develop, strong to isolated severe wind
gusts may occur as activity spreads east before waning this evening.

..Grams/Squitieri.. 01/17/2019

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SPC Jan 17, 2019 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
0142 PM CST Thu Jan 17 2019

Valid 172000Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE GREAT BASIN...

...SUMMARY...
Strong to isolated severe wind gusts will be possible with isolated
thunderstorms across parts of eastern Nevada into western Utah
during the late afternoon and early evening.

...Discussion...
Current forecast reasoning is well-described within the prior
outlook; with clearing/modest heating ongoing across Nevada, and
spreading into western Utah at this time, limited risk for
gusty/damaging winds locally remains evident.

..Goss.. 01/17/2019

.PREV DISCUSSION... /ISSUED 1029 AM CST Thu Jan 17 2019/

...Eastern NV and Western UT...
Guidance differs greatly with the degree and eastern extent of
boundary-layer heating with the NAM substantially cooler than the
RAP, given a pervasive swath of ongoing cloudiness. However,
mid-level drying yielding clearing is evident in satellite imagery
across western NV and this should shift eastward into the afternoon.
In conjunction with mid-level cold-air advection, the setup should
foster increasing destabilization during the afternoon via delayed
boundary-layer heating and lapse rates aloft becoming very steep. 

Mid-level DCVA associated with the portion of the shortwave trough
shifting from northern CA into the Great Basin and convergence along
a cold front should yield a broken band of showers with embedded
thunderstorms by late afternoon from the NV/UT/ID border area
south-southwest into east-central NV. 30-40 kt effective shear could
support modestly organized convective structures. Where inverted-v
thermodynamic profiles can develop, strong to isolated severe wind
gusts may occur as activity spreads east before waning this evening.

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SPC Jan 17, 2019 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
1129 AM CST Thu Jan 17 2019

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
ARKLATEX REGION AND VICINITY...

...SUMMARY...
A few stronger elevated storms -- potentially producing marginally
severe hail -- will be possible Friday evening and overnight across
the Arklatex vicinity.

...Synopsis...
A large upper vortex will linger over eastern Canada Day 2/Friday,
with cyclonic flow extending southward into the Great Lakes and
Northeast.  Meanwhile, a positively tilted southern-stream trough is
progged to gradually amplify as it shifts east-southeastward out of
the Rockies and into the central and southern Plains.  

In conjunction with the trough, a surface low will likewise emerge
from the southern Rockies, and should advance in an eastward arc
across the southern Plains -- eventually reaching the lower
Mississippi Valley/Delta Region by the end of the period.  A
trailing cold front will shift across the southern Plains, reaching
the western Gulf of Mexico late in the period.

...Northeast TX/southeast OK/southwest AR/northwest LA...
Persistent low-level theta-e advection is expected Friday, as
southerly/southwesterly flow increases ahead of the advancing upper
trough.  While the boundary layer should remain largely/slightly
stable through the period across most of the area, gradual/limited
steepening of lapse rates aloft will permit eventual development of
500 to 1000 j/kg elevated CAPE -- maximized across the Arklatex area
and vicinity.

Warm advection showers -- and perhaps eventually a few weak
thunderstorms -- will likely evolve and eventually spread eastward
across the middle and lower Mississippi Valley after dark.  While
low-level shear will be sufficient for rotation in stronger
updrafts, the expected, slightly elevated nature of this convection
and the weak CAPE suggests minimal risk of even a brief/weak
tornado.  Farther west, behind the warm-advection-induced
convection, stronger QG forcing will evolve as the upper trough
nears.  Here, a few stronger, elevated storms may evolve across the
Arklatex region during the evening and into the overnight hours,
aided by the steeper lapse rates/greater CAPE in conjunction with
amply strong flow aloft.  As a result, some hail -- possibly
reaching or exceeding severe levels -- will be possible with the
strongest of these cells.

...MAXIMUM RISK BY HAZARD...
Tornado:  <2%     - None
Wind:     <5%     - None
Hail:      5%     - Marginal

..Goss.. 01/17/2019

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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
1226 PM CST Thu Jan 17 2019

Valid 181200Z - 191200Z

Elevated and locally critical conditions remain possible along/ahead
of the cold front as it pushes south-southeast across portions of
eastern New Mexico/West Texas. This corridor of drier air/stronger
northwest winds will slide southeastward with the front providing a
moving, relatively narrow spatial/temporal window for these
potential elevated/locally critical conditions to occur. Otherwise,
the forecast remains on track and please see the discussion below
for more details.

..Nauslar.. 01/17/2019

.PREV DISCUSSION... /ISSUED 0149 AM CST Thu Jan 17 2019/

...Synopsis...
...Portions of Southwest Texas...

A trough over the Rockies will shift over the Plains on Friday. A
deepening lee cyclone will track east across the southern/central
Plains. The tight pressure gradient on the back side of the low,
coupled with strong deep layer west/northwest flow will result in
windy conditions across the southern High Plains. A cold front will
track south across the central Plains during through the afternoon
and into the southern Plains by evening. Ahead of the front, a dry
airmass will persist across parts of southeast NM into southwest TX.
However, cloud cover could limit heating and prevent lower RH values
from materializing. Currently, the best overlap of marginally low RH
values from 18-25 percent and borderline critical west winds of
15-20 mph (with higher gusts) appears to be across parts of
southwest TX/Big Bend vicinity. Fuel conditions are not overly
impressive for large fires and may temper the overall threat. As
such, only elevated fire weather conditions will be highlighted at
this time.

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

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