Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13
000
ACUS48 KWNS 260853
SWOD48
SPC AC 260851

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0351 AM CDT THU MAY 26 2016

VALID 291200Z - 031200Z

...DISCUSSION...
THE MEDIUM RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH A
LOW-AMPLITUDE UPPER-LEVEL TROUGH IN THE WRN STATES WITH WEST
SOUTHWEST MID-LEVEL FLOW OVER THE NCNTRL STATES. BY SUNDAY
AFTERNOON/DAY 4...MODERATE INSTABILITY IS FORECAST TO BE IN PLACE
ACROSS THE SRN AND CNTRL PLAINS. SCATTERED STRONG THUNDERSTORMS MAY
DEVELOP ACROSS PARTS OF THE WARM SECTOR BUT THE ECMWF AND GFS DIFFER
ON WHERE THE STRONGEST INSTABILITY WILL BE AND HAVE A SLIGHTLY
DIFFERENT UPPER-LEVEL PATTERN. STRONG THUNDERSTORMS WILL AGAIN BE
POSSIBLE MONDAY AFTERNOON AND EVENING/DAY 5 IN PARTS OF THE SRN AND
CNTRL PLAINS WHERE MODERATE INSTABILITY IS FORECAST TO AGAIN
DEVELOP. FURTHER NORTH...BOTH THE GFS AND ECMWF SHOW AN UPPER-LEVEL
TROUGH IN THE NWRN U.S. ON MONDAY BUT KEEP DEEP-LAYER SHEAR
RELATIVELY WEAK AHEAD OF THE TROUGH INTO THE CNTRL PLAINS AND MID MO
VALLEY. IN SPITE OF THIS...A FEW STRONG THUNDERSTORMS COULD DEVELOP
IN AREAS THAT CAN BECOME MODERATELY UNSTABLE. ON TUESDAY/DAY
6...BOTH SOLUTIONS MOVE THE UPPER-LEVEL TROUGH EWD WITH THE ECMWF
MUCH FASTER THAN THE GFS. THE ECMWF ALSO DRIVES A COLD FRONT SEWD
ACROSS THE NCNTRL STATES WHILE THE GFS KEEPS AN UNSTABLE AIRMASS IN
THE NRN PLAINS. STRONG THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE
ACROSS PARTS OF THE CNTRL AND NRN PLAINS TUESDAY AFTERNOON AND
EVENING DEPENDING UP THE POSITIONING OF THE FRONT AND THE TIMING OF
THE APPROACHING UPPER-LEVEL TROUGH. ON WEDNESDAY/DAY 7 AND
THURSDAY/DAY 8...THE MODELS SHOW VERY DIFFERENT SCENARIOS SUGGESTING
PREDICTABILITY CONTINUES TO BE LOW FOR LATE IN THE DAY 4 TO 8
PERIOD.

..BROYLES.. 05/26/2016


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