Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 201954
SWODY1
SPC AC 201953

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0253 PM CDT SUN APR 20 2014

VALID 202000Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF WRN/NWRN TX AND
ADJACENT SWRN OK...

...SUMMARY...
SCATTERED THUNDERSTORMS -- A FEW WITH POTENTIAL TO PRODUCE HAIL AND
DAMAGING GUSTS -- WILL CONTINUE TO EVOLVE ACROSS PORTIONS OF THE
WESTERN HALF OF TEXAS AND FAR SOUTHWEST OKLAHOMA THIS AFTERNOON AND
EARLY EVENING.

...DISCUSSION...
SHOWERS AND SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP OVER THE WRN
HALF OF THE SRN PLAINS THIS AFTERNOON -- PER EARLIER OUTLOOKS.  ONE
CLUSTER OF WEAK CONVECTION -- ASSOCIATED WITH A SUBTLE UPPER
CIRCULATION CENTER -- IS MOVING ENEWD ACROSS N TX ATTM.  MEANWHILE
BEHIND THIS FEATURE AND ASSOCIATED CLOUD COVER...AIRMASS
HEATING/DESTABILIZATION ARE ONGOING AHEAD OF A WEAK TROUGH/DRYLINE E
OF THE TX/NM BORDER.  AIDED BY ASCENT ASSOCIATED WITH THE MAIN UPPER
FEATURE NOW CENTERED OVER FAR NWRN PORTIONS OF THE TX
PANHANDLE...ISOLATED STORM DEVELOPMENT IS ONGOING FROM THE TX/OK
PANHANDLE VICINITY SWD INTO THE DAVIS MTNS.  WITH FLOW ALOFT
RELATIVELY WEAK INVOF THE UPPER CIRCULATION CENTER...MARGINAL HAIL
WILL LIKELY BE THE MAIN SEVERE RISK.  FARTHER S...WHERE MID-LEVEL
FLOW IS A BIT MORE ROBUST...MULTICELL/WEAK SUPERCELL STORMS CAN BE
EXPECTED...WITH ATTENDANT RISK FOR LOCALLY DAMAGING WINDS AND HAIL.
FOR ADDITIONAL SHORT-TERM INFORMATION...PLEASE REFER TO SWOMCD 0373.
 LATER THIS EVENING...CONVECTIVE INTENSITY/SEVERE RISK WILL DIMINISH
IN CONJUNCTION WITH DIURNAL BOUNDARY-LAYER STABILIZATION.

..GOSS.. 04/20/2014

.PREV DISCUSSION... /ISSUED 1131 AM CDT SUN APR 20 2014/

...SYNOPSIS...
MODEST...SLOWLY PROGRESSIVE SPLIT FLOW PATTERN WILL PREVAIL OVER THE
CONUS THROUGH MON...DOWNSTREAM FROM BROAD/FAIRLY DEEP LOW OVER THE
NE PACIFIC. IN THE SRN BRANCH...TROUGH NOW OVER ERN NM SHOULD MOVE
ENE TO THE ERN TX PANHANDLE THIS EVE BEFORE CONTINUING ENE TO ERN
KS/OK EARLY MON...WITH AN INCREASING POSITIVE TILT. WITHIN THE
TROUGH...LEAD IMPULSE OVER WRN OK ATTM SHOULD WEAKEN AS IT PIVOTS
NNE INTO ERN KS/WRN MO WHILE UPSTREAM VORT LOBE NOW OVER ERN NM/FAR
W TX TURNS NE TOWARD CNTRL PORTIONS OF OK/N TX. ELSEWHERE...A
STRONGER TROUGH IN THE NRN BRANCH WILL MOVE FROM CNTRL MT TO ERN
ND/NRN MN BY 12Z MON.

FEATURES WILL REMAIN WEAK AT LWR LVLS. A LOW SHOULD REMAIN NEARLY
STNRY OVER SE CO/SW KS TODAY...WHILE A NEW CIRCULATION CENTER
EVOLVES ALONG LEE TROUGH/DRY LINE OVER E CNTRL NM/W CNTRL TX. THIS
LOW SHOULD EDGE E/NE INTO NW TX EARLY MON. FARTHER N...WEAK NRN
STREAM FRONT STALLED OVER THE CNTRL PLNS SHOULD REDEVELOP NWD THIS
AFTN...BEFORE RESUMING A SEWD ADVANCE TNGT/EARLY MON IN WAKE OF
MT/ND UPR IMPULSE.

LEE TROUGH/DRY LINE WILL BE THE FOCUS FOR SOME DIURNAL STORMS OVER
PARTS OF WRN AND NW TX LATER TODAY...WHERE THE PRESENCE OF ADEQUATE
VERTICAL SHEAR AND INSTABILITY SUGGEST AN ASSOCIATED POTENTIAL FOR
SVR HAIL/WIND. OTHERWISE...THE LIKELIHOOD FOR SVR TSTMS APPEARS LOW.


...SRN PLNS TODAY THROUGH EARLY TNGT...
SATELLITE DATA SUGGEST THAT APPRECIABLE SFC HEATING WILL OCCUR TODAY
INVOF LEE TROUGH/DRY LINE SEGMENTS EXTENDING SSW FROM SW KS SFC LOW
INTO FAR ERN NM/W TX...IN WAKE OF ELEVATED CONVECTION NOW COVERING
MUCH OF OK AND NW TX. THE LEE TROUGH/DRY LINE SEGMENTS...AND
DIFFERENTIAL HEATING ZONES ON THE SW SIDE OF THE ELEVATED CONVECTION
AREA...SHOULD SERVE AS THE FOCUS FOR LOW-LVL UPLIFT/STORM
DEVELOPMENT BY MID TO LATE AFTN. UPLIFT AHEAD OF NM VORT LOBE WILL
FURTHER ASSIST DEVELOPMENT.

POSITIVE-TILT OF ERN NM TROUGH WILL KEEP THE STRONGEST /40-50 KT/
DEEP SHEAR DISPLACED FARTHER S AND E ACROSS TX. SUFFICIENT /30-40
KT/ WSWLY DEEP SHEAR WILL BE PRESENT...HOWEVER...TO PROMOTE STORM
ORGANIZATION/SUSTENANCE AND THE POTENTIAL FOR COUPLE SUPERCELLS
CLOSER TO THE TROUGH AXIS OVER WRN AND NW TX. AND...WHILE REGION
WILL REMAIN ON THE FRINGE OF PW PLUME EXTENDING N/NE ACROSS CNTRL
AND E TX...AMPLE MOISTURE PW AROUND 1 INCH/ SHOULD EXIST TO BOOST
MLCAPE INTO THE 1000-1500 J/KG RANGE GIVEN RELATIVELY COOL 500 MB
TEMPERATURES /AROUND MINUS 13 C/. THIS ACTIVITY MAY MERGE INTO A
SMALL CLUSTER OR TWO THIS EVE...WITH THE CLUSTERS MOVING GENERALLY E
BEFORE WEAKENING OVER NW OR N CNTRL TX LATER TNGT.

UPSLOPE-INDUCED STRATUS AND WARMER MID-LVL TEMPERATURES SHOULD KEEP
STORM DEVELOPMENT MORE LIMITED WITH SWD EXTENT FROM THE SLIGHT RISK
AREA...ALTHOUGH AN ISOLD STORM OR TWO /INCLUDING A SUPERCELL/ COULD
OCCUR LATE THIS AFTN OVER OR JUST E OF THE DAVIS MOUNTAINS.




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