Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 041951
SWODY1
SPC AC 041949

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0249 PM CDT MON MAY 04 2015

VALID 042000Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SWRN TX/ERN NM AND THE SRN
HIGH PLAINS ACROSS KS TO THE MIDDLE MS VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT RISK
FROM THE SRN HIGH PLAINS ACROSS THE MIDDLE MS VALLEY INTO OH...

...SUMMARY...
A FEW SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING
FROM WEST TEXAS AND EASTERN NEW MEXICO ACROSS PARTS OF KANSAS INTO
SOUTHERN IOWA AND NORTHERN MISSOURI TO WEST-CENTRAL ILLINOIS.

SATELLITE AND RADAR ANIMATIONS SUGGEST AN MCV IS MOVING SLOWLY NNEWD
OVER NERN NM NEAR TCC.  STRONG/SEVERE STORMS ARE INCREASING ALONG
THE ERN PERIPHERY OF THE MCV OVER NERN NM AND THE WRN TX PANHANDLE.
ALTHOUGH SWLY WINDS ALOFT OVER THIS AREA ARE MODEST AT BEST /20-25
KT AT 500 MB/...STRONG DIABATIC HEATING IS OCCURRING DOWNSTREAM FROM
THIS CONVECTION WHICH IS RESULTING IN MODERATE INSTABILITY WITH
MLCAPE OF 1500-2000 J/KG.  GIVEN THE THREAT FOR SEVERE STORMS TO
SPREAD FROM NERN NM/TX PANHANDLE INTO SWRN KS...THE EARLIER MARGINAL
RISK OVER THIS REGION HAS BEEN CHANGED TO SLIGHT RISK...WITH AN
ELONGATED SLIGHT RISK AREA NOW EXTENDING FROM SWRN TX ACROSS KS INTO
THE NRN MO/SRN IA REGION.

IN ADDITION...THE WRN EDGE OF THE SLIGHT RISK OVER SWRN TX/SERN NM
HAS BEEN MOVED WWD TO ALIGN WITH THE LOCATION OF THE OROGRAPHICALLY
GENERATED INITIAL STORMS.  THIS ACTIVITY IS EXPECTED TO SPREAD
EWD/NEWD AS STRONGER WSWLY WINDS IN THE MID-UPPER LEVELS GRADUALLY
INCREASE AND SPREAD EWD INTO THE SWRN TX REGION.

OTHERWISE...PREVIOUS 1630Z OUTLOOK APPEARS TO BE ON TRACK.

..WEISS.. 05/04/2015

.PREV DISCUSSION... /ISSUED 1116 AM CDT MON MAY 04 2015/

...NM/TX...
WATER VAPOR LOOP SHOWS AN UPPER TROUGH OVER SOUTHERN AZ/NORTHERN
MEXICO...WITH A RATHER STRONG SUBTROPICAL JET NOSING INTO SOUTHWEST
TX.  LARGE SCALE ASCENT AHEAD OF THIS TROUGH WILL AFFECT EASTERN
NM/WEST TX THIS AFTERNOON AND TONIGHT...LEADING TO RATHER WIDESPREAD
SHOWER AND THUNDERSTORM ACTIVITY.  CONVECTION IS EXPECTED TO FORM
OVER THE HIGHER TERRAIN OF CENTRAL/SOUTHEAST NM AND SOUTHWEST TX BY
MID AFTERNOON...SPREADING SLOWLY EASTWARD DURING THE EARLY EVENING.
FORECAST SOUNDINGS SHOW RATHER STRONG WESTERLY MID/UPPER LEVEL
WINDS...PROVIDING FAVORABLE EFFECTIVE SHEAR VALUES FOR
ORGANIZED/SUPERCELL STRUCTURES.  LARGE HAIL IS PROBABLY THE MAIN
THREAT FROM THE MOST INTENSE STORMS...ALTHOUGH AN ISOLATED TORNADO
OR TWO IS POSSIBLE EARLY THIS EVENING AS LOW LEVEL SHEAR VALUES
STRENGTHEN SOMEWHAT.

...KS/NEB/MO/IA/IL...
A SURFACE BOUNDARY CURRENTLY EXTENDS FROM SOUTHWEST KS INTO NORTHERN
MO AND NORTHERN IL.  SCATTERED CLOUDS AND ISOLATED THUNDERSTORMS
HAVE BEEN OCCURRING NORTH OF BOUNDARY...WITH STRONGER DIURNAL
HEATING TO THE SOUTH.  BY LATE AFTERNOON...MLCAPE VALUES OF 1500+
J/KG ARE POSSIBLE IN THIS REGION...WITH MOST MODEL SOLUTIONS
AGREEING ON SEVERAL HOURS OF THUNDERSTORM ACTIVITY.  LARGE SCALE
FORCING IS WEAK AND MID/UPPER LEVEL FLOW IS SOMEWHAT MARGINAL FOR
ORGANIZED STORMS IN THE WARM SECTOR.  NEVERTHELESS...A FEW CLUSTERS
OF STRONG/SEVERE CONVECTION ARE EXPECTED ALONG THIS CORRIDOR THIS
AFTERNOON AND EVENING.  LOCALLY DAMAGING WINDS AND HAIL ARE THE MAIN
THREATS.  STORMS MAY SPREAD EASTWARD ACROSS SOUTHERN IA/NORTHERN MO
AND POTENTIALLY INTO NORTHWEST IL THIS EVENING WITH A CONTINUED
SEVERE RISK.




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