Skip Navigation Links weather.gov 
NOAA logo-Select to go to the NOAA homepage NOAA's National Weather Service   Select to go to the NWS homepage
Storm Prediction Center
navigation bar left  
  navigation bar end cap


 
USA.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

< Day 1 Outlook   Day 3 Outlook >
Jan 21, 2018 1730 UTC Day 2 Convective Outlook
Updated: Sun Jan 21 16:59:50 UTC 2018 (Print Version | 20180121 1730Z Day 2 shapefile | 20180121 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Probabilistic
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

 Forecast Discussion

   SPC AC 211659

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1059 AM CST Sun Jan 21 2018

   Valid 221200Z - 231200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS WESTERN
   ILLINOIS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHEAST...

   ...SUMMARY...
   A few strong, to possibly severe, thunderstorms are possible across
   portions of the Southeast and across western Illinois Monday
   afternoon.

   ...Midwest...

   Late-morning satellite imagery depicts a well-defined upper low over
   CO/NM region shifting east-northeast in line with earlier model
   guidance. This low will deepen as it translates to a position over
   northwest MO at 18z and near UIN by 23/00z. Intense mid-level height
   falls will spread across the Midwest and a mature surface cyclone
   with an attendant front will surge toward the MS River by early
   afternoon. Latest observational data indicates 50F surface dew
   points have advanced as far north as the STL area and lower 50s
   should be in place across western IL prior to the wind shift. It
   appears a narrow wedge of buoyancy, sufficient for potentially
   robust updrafts, will develop immediately ahead of the cold front by
   18z as surface-3km lapse rates approach 7 C/km. Forecast soundings
   suggest isolated, discrete thunderstorms should develop shortly
   after 18z along the wind shift from southeast of STL to east of UIN,
   then spread toward central IL before weakening in the presence of
   more stable boundary layer. Current thinking is a brief opportunity
   exists (2-4 hours) for a few storms to approach severe levels
   immediately ahead of the front, within favorably forced left-exit
   region, just ahead of upper low. Locally damaging winds/small hail
   are the greatest risks.

   ...Southeast...

   Large-scale forcing for ascent will glance the I-20 corridor across
   the central Gulf States Monday with negligible influence farther
   south along the Gulf Coast. Even so, a notable pre-frontal surface
   confluence zone will shift into southeast MS by 18z and into
   southwest AL by 23/00z. Greatest risk for potentially organized
   convection should be noted within a secondary surge of
   moisture/instability that will advance inland ahead of the
   confluence zone. While deep-layer shear is more than adequate for
   sustaining organized storms the absence of large-scale ascent should
   limit storm coverage/intensity across this region.

   ..Darrow.. 01/21/2018

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0700Z

        
Top/Latest Day 1 Outlook/Today's Outlooks/Forecast Products/Home
Weather Topics:
Watches, Mesoscale Discussions, Outlooks, Fire Weather, All Products, Contact Us

NOAA / National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.
spc.feedback@noaa.gov
Page last modified: January 21, 2018
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities