Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 261958
SWODY1
SPC AC 261957

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0257 PM CDT THU MAY 26 2016

VALID 262000Z - 271200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF CNTRL KS INTO FAR
NWRN OK...

...THERE IS AN ENH RISK OF SVR TSTMS OVER MUCH OF KS...SRN NEB...WRN
OK...W TX...AND NWRN MO/SWRN IA...

...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE CNTRL AND SRN
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS MUCH OF THE CENTRAL
U.S....

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF TORNADOES...VERY LARGE HAIL...AND
DAMAGING WINDS ARE EXPECTED THURSDAY ACROSS MUCH OF THE SOUTHERN
NEBRASKA...KANSAS...WESTERN OKLAHOMA...AND PARTS OF WEST-CENTRAL
TEXAS.  ISOLATED LARGE HAIL AND DAMAGING WINDS WILL OTHERWISE BE
POSSIBLE OVER A BROAD AREA OF THE CENTRAL AND SOUTHERN PLAINS.

...NW OK INTO KS...
AN INITIAL RASH OF STORMS CONTAINING MAINLY HAIL CONTINUES TO SHIFT
NWD ACROSS E CNTRL AND NERN KS. A LOCALIZED TORNADO THREAT APPEARS
TO BE DEVELOPING OVER NERN KS AND POSSIBLY INTO NWRN MO OVER THE
NEXT FEW HOURS AS LARGE CELLS EVOLVE AND MOVE TOWARD THE OUTFLOW
BOUNDARY FROM EARLIER STORMS. HAVE EXPANDED THE ENHANCED RISK EWD
ACROSS THE KANSAS CITY AREA.

TO THE SW...ANOTHER ZONE OF STORMS...INCLUDING SOME SUPERCELLS...IS
EVOLVING NEAR THE DRYLINE FROM S CNTRL KS INTO NWRN OK. IT IS
EXPECTED THAT WITH TIME...WIND PROFILES WILL BECOME MORE FAVORABLE
FOR TORNADOES AS THE LOW-LEVEL JET INCREASES. IN ADDITION...POCKETS
OF DRY AIR HAVE BEEN MOVING THROUGH THE BOUNDARY LAYER FROM S TO
N...EVIDENT IN MESONET OBS AND IN THE WAKE OF EARLIER SMALL STORMS.
THIS COULD ALSO TEMPORARILY DISRUPT STORMS. A SIGNIFICANT TORNADO OR
TWO STILL APPEARS POSSIBLE ACROSS THE MDT RISK AREA.

...SERN TX...
A COMPLEX OF STORMS PERSIST THIS AFTERNOON OVER SERN TX WITH
EMBEDDED SUPERCELLS PRODUCING BRIEF TORNADOES. RADAR AT 2000Z
SUGGESTS A LIKELY TORNADO OVER WASHINGTON COUNTY. LOW-LEVEL CAPE
REMAINS VERY HIGH WITH DEWPOINTS IN THE MID 70S F AND THE COMPLEX OF
STORMS IS PROVIDING ITS OWN OUTFLOW BOUNDARY WHERE IT CAN ENHANCE
LOW-LEVEL SHEAR ON THE SRN FLANK. THEREFORE HAVE ADDED A SMALL
SLIGHT RISK FOR ISOLATED TORNADOES THIS AFTERNOON.

..JEWELL.. 05/26/2016

.PREV DISCUSSION... /ISSUED 1130 AM CDT THU MAY 26 2016/

...NEB/KS...
MORNING SURFACE ANALYSIS SHOWS A DEEPENING LOW NEAR DDC...WITH A
WARM FRONT EXTENDING EASTWARD ACROSS CENTRAL/EASTERN KS.  A VERY
MOIST AND EXTREMELY UNSTABLE AIR MASS IS PRESENT IN THE WARM SECTOR
OF THE LOW...WHERE NEAR DRY-ADIABATIC MID LEVEL LAPSE RATES WILL
CONTRIBUTE TO AFTERNOON MLCAPE VALUES OVER 4000 J/KG.  GIVEN THE
APPROACHING UPPER TROUGH AND STRENGTHENING WIND FIELDS THIS
AFTERNOON...IT APPEARS THERE IS A CHANCE OF AN ACTIVE SEVERE WEATHER
EVENT OVER PARTS OF KS AND SOUTHERN NEB.

STORMS WILL LIKELY DEVELOP BY MID AFTERNOON NEAR THE SURFACE LOW
OVER SOUTHWEST KS...AND TRACK NORTHEASTWARD THROUGH THE
AFTERNOON/EVENING ALONG THE WARM FRONT ACROSS THE MDT RISK AREA.
MODEL SOLUTIONS SUGGEST THE EVOLUTION OF THESE STORMS MAY BE MESSY
WITH MIXED MODES.  HOWEVER...THE UNUSUALLY FAVORABLE THERMODYNAMIC
ENVIRONMENT...COUPLED WITH INCREASING LARGE SCALE FORCING AND WIND
FIELDS SUFFICIENT FOR SUPERCELLS...SUGGESTS THE RISK OF STRONG
TORNADOES AND VERY LARGE HAIL.  THERE IS SOME RISK OF MULTIPLE
ROUNDS OF CONVECTION OVER CENTRAL KS AS STORMS EMANATING FROM CO
MOVE INTO THE AREA AFTER DARK.

...WESTERN OK/WEST TX...
MODEL SOLUTIONS ARE HAVING A HARD TIME HANDLING THE STEEP LAPSE
RATES AND EARLY CONVECTION OVER PARTS OF TX/OK.  THIS IS LEADING TO
RAPID BOUNDARY-LAYER DRYING/STABILIZATION IN SEVERAL MODEL
SOLUTIONS.  WHILE THIS MAY BE PARTIALLY CORRECT...IT IS LIKELY
OVERDONE.  IT APPEARS MORE LIKELY THAT STRONG INSTABILITY WILL BE
MAINTAINED ALONG THE DRYLINE THIS AFTERNOON...WHERE SCATTERED
SUPERCELL STORMS ARE FORECAST TO DEVELOP BY MID/LATE AFTERNOON.
VERY LARGE HAIL AND DAMAGING WINDS ARE THE MAIN THREATS...BUT A FEW
TORNADOES ARE ALSO POSSIBLE.  THE MAIN TORNADO THREAT APPEARS TO
EXIST OVER NORTHWEST OK WHERE THE BEST COMBINATION OF WIND FIELDS
AND FORCING WILL OVERLAP.

$$


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