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 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
000
ACUS01 KWNS 260603
SWODY1
SPC AC 260602

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0102 AM CDT THU MAY 26 2016

VALID 261200Z - 271200Z

...THERE IS AN ENH RISK OF SVR TSTMS ACROSS THE NEB/KS VICINITY...

...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PORTIONS OF WRN AND
CENTRAL TX...

...THERE IS A SLGT RISK OF SVR TSTMS COVERING A LARGE PORTION OF THE
CENTRAL AND SRN PLAINS...AND PARTS OF THE MID AND LOWER MO VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS EXTENDING FROM THE UPPER MS
VALLEY/UPPER GREAT LAKES REGION SSWWD TO THE RIO GRANDE...

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF TORNADOES AND VERY LARGE HAIL ARE
EXPECTED THURSDAY ACROSS MUCH OF THE SOUTHERN NEBRASKA AND KANSAS
VICINITY...AND POSSIBLY INTO NORTHEAST COLORADO...AND EXTENDING
SOUTHWARD INTO THE SOUTHERN PLAINS.  OTHER MARGINALLY SEVERE STORMS
WITH HAIL AND STRONG WIND GUSTS MAY OCCUR ACROSS PARTS OF THE MID
AND UPPER MISSISSIPPI VALLEY AND WESTERN UPPER GREAT LAKES REGION.

...SYNOPSIS...
STEADY EWD PROGRESSION OF WRN U.S. TROUGH IS FORECAST FOR
THURSDAY...WITH THE SYSTEM CROSSING THE ROCKIES THROUGH THE DAY AND
NOSING INTO WRN PORTIONS OF THE PLAINS STATES WITH TIME.  AS HEIGHT
FALLS OVERSPREAD THE CENTRAL PORTION OF THE COUNTRY...A LEE LOW OVER
THE CENTRAL HIGH PLAINS IS FORECAST TO DEEPEN INTO WRN KS DURING THE
AFTERNOON...WITH A WARM FRONT EXTENDING NEWD INTO SRN NEB.  THIS LOW
AND WARM FRONT...A DRYLINE EXTENDING SWD ACROSS OK/TX...AND RESIDUAL
OUTFLOW BOUNDARIES IN THE WARM SECTOR WILL LIKELY FOCUS SEVERAL
AREAS OF SEVERE STORMS THROUGH THE PERIOD.

...CENTRAL AND SRN PLAINS VICINITY...
A VERY COMPLEX/UNCERTAIN SCENARIO IS UNFOLDING ONCE AGAIN FOR
THURSDAY WITH RESPECT TO TIMING/LOCATION AND SPECIFICS OF EVOLUTION
OF WHAT WILL LIKELY BECOME WIDESPREAD CONVECTION ACROSS PARTS OF THE
CENTRAL AND SRN PLAINS REGION.  ONGOING STORMS ATTM -- AND
ADDITIONAL EXPANSION OF CONVECTION THROUGH THURSDAY MORNING -- WILL
BE THE PRIMARY COMPLICATING FACTOR...WITH SWATHS OF THE WARM SECTOR
BECOMING CONVECTIVELY OVERTURNED AND ASSOCIATED OUTFLOW BOUNDARIES
BECOMING ESTABLISHED IN HERETOFORE UNCERTAIN LOCATIONS.

WITH THAT SAID...THE BROADER PICTURE -- WHICH INCLUDES A LARGE WRN
UPPER TROUGH AND ASSOCIATED/ENHANCED SWLY FLOW ALOFT SPREADING EWD
TOWARD THE PLAINS ALONG WITH A VERY MOIST WARM SECTOR BENEATH VERY
STEEP LAPSE RATES THROUGH MUCH OF THE TROPOSPHERE -- IS SUGGESTIVE
OF AT LEAST LOCALLY SUBSTANTIAL SEVERE POTENTIAL.  ALONG WITH RISK
FOR VERY LARGE HAIL...LOCALLY DAMAGING WINDS AND TORNADOES WILL ALSO
BE POSSIBLE.  ATTM...TWO MAIN CORRIDORS OF SEVERE RISK INCLUDE:

1.  SRN NEB AND MUCH OF KS -- AND POSSIBLY INTO NERN CO -- INVOF THE
FORECAST-TO-BE-DEEPENING SURFACE LOW AND ASSOCIATED WARM FRONT...AND
POTENTIALLY AN OUTFLOW BOUNDARY LINGERING OVER CENTRAL AND ERN KS

2.  PARTS OF W CENTRAL TX INCLUDING THE CONCHO VALLEY AND BIG
COUNTRY REGIONS AHEAD OF THE DRYLINE

AS MENTIONED ABOVE...VERY STEEP LAPSE RATES ALOFT /AWAY FROM AREAS
WHICH EXPERIENCE PRIOR CONVECTIVE OVERTURNING/ ATOP A VERY MOIST
BOUNDARY LAYER WILL PROVIDE A VERY FAVORABLE THERMODYNAMIC
ENVIRONMENT TO SUPPORT VIGOROUS STORMS...AND 45-55 KT SWLY MID-LEVEL
FLOW SPREADING EWD ON THE ERN PERIPHERY OF THE UPPER SYSTEM WILL
CONTRIBUTE TO SHEAR SUPPORTIVE OF SUPERCELLS.  AGAIN
THOUGH...NARROWING DOWN TIMING AND SPECIFIC LOCALES OF GREATEST RISK
REMAIN DIFFICULT ATTM...WITH AN ARRAY OF THE LATEST PARAMETERIZED
AND CONVECTION-ALLOWING MODELS EXHIBIT DIVERSE/DISPARATE SOLUTIONS
REGARDING CONVECTIVE TIMING/INITIATION/PROGRESSION.  THOUGH THE
ENVIRONMENT APPEARS SUPPORTIVE OF RISK FOR VERY LARGE
HAIL...DAMAGING WINDS...AND A FEW TORNADOES...DETAILS PRECLUDE ANY
FURTHER SPECIFICATION ATTM.

...UPPER MS VALLEY/UPPER GREAT LAKES VICINITY...
ISOLATED STRONG/LOCALLY SEVERE STORMS WILL BE POSSIBLE ACROSS
PORTIONS OF THE UPPER MS VALLEY/WRN UPPER GREAT LAKES REGION
THURSDAY AS SHORT-WAVE TROUGHING SHIFTS ACROSS THE AREA DURING THE
AFTERNOON.  WHILE AT LEAST PARTS OF THIS REGION -- LIKE AREAS
FARTHER S -- WILL LIKELY EXPERIENCE EARLY PERIOD CONVECTION...SOME
DESTABILIZATION COMBINED WITH MODERATE /40 TO 45 KT/ MID-LEVEL WLYS
WILL SUPPORT RISK HAIL/DAMAGING WINDS WITH A FEW OF THE STRONGEST
STORMS.

..GOSS/MOSIER.. 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.