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SPC - No watches are valid as of Mon Nov 20 17:17:01 UTC 2017

No watches are valid as of Mon Nov 20 17:17:01 UTC 2017.


SPC - No MDs are in effect as of Mon Nov 20 17:17:01 UTC 2017

No Mesoscale Discussions are in effect as of Mon Nov 20 17:17:01 UTC 2017.


SPC Nov 20, 2017 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0621 AM CST Mon Nov 20 2017

Valid 201300Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for severe thunderstorms appears negligible across the U.S.
today through tonight.

...Synopsis...
Gradual amplification of the western ridge/eastern trough pattern is
expected through Tuesday.  An embedded shortwave trough over the Rio
Grande Valley will progress to the central Gulf of Mexico by
tonight, with some potential for very weak surface cyclogenesis
across the eastern Gulf in association with ascent preceding the
wave and air mass modification over the loop current.  Isolated
lightning flashes have been observed this morning with convection
crossing the Rio Grande, and 12z soundings from CRP/BRO confirm
sufficient buoyancy rooted near or above 700 mb to sustain a
thunderstorm threat through the morning across deep south TX.  

Otherwise, low-level moistening/destabilization is expected across
the southeast FL coast as a front stalls and then retreats back to
the north tonight.  Only shallow convective showers are expected
today across southeast FL, but moistening could become sufficient
for deeper convection and isolated lightning flashes overnight.

..Thompson.. 11/20/2017

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SPC Nov 20, 2017 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
0949 AM CST Mon Nov 20 2017

Valid 201630Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for severe thunderstorms appears negligible across the U.S.
today through tonight.

Scattered showers and thunderstorms will affect Deep South TX for a
few more hours, and a few thunderstorms may form over South FL later
this afternoon.  But otherwise, the nation will see relatively dry
and stable conditions that are unfavorable for deep convection.  No
severe storms are forecast today.

..Hart/Jewell.. 11/20/2017

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SPC Nov 20, 2017 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
1115 AM CST Mon Nov 20 2017

Valid 211200Z - 221200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
No severe weather is expected in the contiguous United States
Tuesday or Tuesday night.

...DISCUSSION...
An upper-level trough will move across the Mississippi Valley on
Tuesday as a cold front advances southeastward across the
south-central U.S. A few thunderstorms may develop ahead of the
front in a moist airmass located across the middle to upper Texas
Coast. A warm and moist airmass will also be in place across the
Florida Peninsula where thunderstorms will also be possible Tuesday
afternoon. The potential for isolated thunderstorm development will
also exist near the coast of South Carolina and North Carolina. No
severe weather is expected Tuesday or Tuesday night.

..Broyles.. 11/20/2017

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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
1100 AM CST Mon Nov 20 2017

Valid 201700Z - 211200Z

...CRITICAL FIRE WEATHER AREA FOR EAST-CENTRAL NEW MEXICO...
...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CO...A SMALL PART OF
SOUTHWEST NE/SOUTHERN NE PANHANDLE/NORTHWEST KS...

...Central High Plains...
A critical area has been added for portions of the central High
Plains, with critical wind/RH already being observed over portions
of far southeast WY and the NE Panhandle and these conditions likely
to spread southeast during the afternoon. 

...East-central NM into portions of west TX and south-central CO...
Critical conditions are still expected to develop over portions of
east-central NM this afternoon, with elevated/locally critical
conditions extending eastward into portions of west TX and northward
into south-central CO. See the previous discussion below for more
details. 

...OK/North TX northeast into Iowa...
The elevated area has been expanded to include portions of western
north TX northeast through OK, eastern KS, western MO, IA, and
eastern NE. A strong low-level jet will allow for strong
southwesterly winds this afternoon, with sustained winds of 20-30
mph expected. Morning soundings reveal very limited moisture, with
PW values generally below 0.25". Heating/mixing this afternoon
should allow for minimum RH values in the 20-30% range, sufficient
for elevated fire weather conditions given the strong winds.

..Dean.. 11/20/2017

.PREV DISCUSSION... /ISSUED 0128 AM CST Mon Nov 20 2017/

...Synopsis...
The upper-level pattern is forecast to become more amplified today,
as a ridge builds over the West.  As a result, strong northwesterly
flow aloft will impinge upon the central/southern Rockies.  At the
surface, a low pressure system will move eastward across
south-central Canada with a trough of low pressure extending
southward across the central/southern High Plains.

...East-central NM into portions of west TX and south-central CO...
Strong downslope flow across the region will aid in the downward
transport of high momentum air from aloft, resulting in dry and
breezy conditions at the surface.  The most likely location for
critical fire weather conditions is expected across east-central New
Mexico in the immediate lee of the higher terrain, where sustained
afternoon westerly surface wind speeds of 20-25 mph (with gusts over
30 mph by late afternoon) will coincide with RH values around 10%. 
Elsewhere, elevated fire weather conditions are expected as RH
values fall below 15% with sustained winds of 15-20 mph.

...Portions of the central High Plains...
The winds aloft will be even stronger to the north, where downslope
flow will contribute to strong and gusty westerly surface winds,
especially in the immediate lee of the higher terrain in
southeastern Wyoming.  However, there is substantial uncertainty in
reaching critical RH values in that region, precluding the issuance
of a critical area at this time.  Farther east over the plains,
sustained wind speeds will be weaker (15-20 mph), but critical RH
values appear more likely, resulting in elevated fire weather
conditions.

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

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