Severe Storm Outlook Narrative (AC)
Issued by NWS

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723
ACUS01 KWNS 291631
SWODY1
SPC AC 291630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT SUN MAY 29 2016

VALID 291630Z - 301200Z

...THERE IS AN ENH RISK OF SVR TSTMS OVER PARTS OF SW TX...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN PLNS...

...THERE IS A MRGL RISK OF SVR TSTMS OVER A LARGER PART OF THE SRN
PLNS...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE CNTRL
GRT/LKS/MID-OH VLY...

...SUMMARY...
WIDELY SCATTERED SEVERE STORMS WITH LARGE HAIL...DAMAGING WIND...AND
A FEW TORNADOES WILL OCCUR OVER WESTERN PORTIONS OF THE SOUTHERN
PLAINS...MAINLY THIS AFTERNOON AND EVENING.

...SYNOPTIC SETUP...
TWO-STREAM FLOW WILL PREVAIL OVER THE LWR 48 THROUGH MEMORIAL DAY.
IN THE NRN BRANCH...SYSTEM THAT CROSSED THE CNTRL STATES IN RECENT
DAYS IS NOW OVER LK MI. THE SYSTEM SHOULD FURTHER WEAKEN AS IT
CONTINUES ENE INTO ERN ONT...ROUNDING N SIDE OF DOMINANT WRN
ATLANTIC RIDGE. IN THE SRN STREAM...LOW NOW OVER THE SRN CA CST
SHOULD MOVE SLOWLY E INTO THE LWR CO VLY BY THE END OF THE
PERIOD...PRECEDED BY A SERIES OF WEAK DISTURBANCES DOWNSTREAM ACROSS
THE SRN RCKYS/SRN PLNS. FARTHER E IN THE SRN STREAM...TROPICAL
SYSTEM BONNIE HAS WEAKENED TO A TD. PER NHC...LITTLE CHANGE IN
INTENSITY IS EXPECTED AS THE SYSTEM TURNS NE ACROSS ERN PORTIONS OF
THE SC CSTL PLNS LATER TDA. SFC FEATURES ALSO WILL REMAIN WEAK
ELSEWHERE ACROSS THE CONUS...WITH A FRONTOLYTIC COLD FRONT CROSSING
MI/IND/OH...AND COMPOSITE OUTFLOW BOUNDARIES DOMINATING THE PATTERN
OVER THE SRN PLNS.

...SRN PLNS TODAY/TNGT...
SSELY LWR TROPOSPHERIC FLOW WILL PERSIST THROUGH THE PERIOD OVER WRN
PORTIONS OF THE SRN PLNS AS SRN STREAM JET MAINTAINS LEE TROUGH OVER
ERN NM. OVERNIGHT MCSS OVERTURNED THE BOUNDARY LAYER ACROSS MUCH OF
W CNTRL...N CNTRL...AND S CNTRL TX...BUT LEFT SW TX LARGELY
UNTOUCHED. DIURNAL STRENGTHENING OF LEE LOW AND CONTINUED LOW-LVL
MOISTURE INFLOW WILL RESULT IN VERY STRONG INSTABILITY /MLCAPE AOA
3000 J PER KG/ OVER SW TX AND FAR SE NM LATER TODAY...SW OF DIFFUSE
COMPOSITE OUTFLOW BOUNDARY EXPECTED TO BE ORIENTED ROUGHLY ALONG A
MAF-SJT AXIS.

HIGH-LVL CLOUDS NOW OVER ERN NM/W TX APPEAR TO BE RELATED TO A
LOW-AMPLITUDE DISTURBANCE NOW OVER WRN NM...AND TEMPORARILY WILL
DIMINISH SFC HEATING. BUT AS THESE CLOUDS SHIFT EWD LATER
TODAY...COMBINATION OF LOW-LVL DESTABILIZATION...MOIST UPSLOPE
FLOW...AND ASCENT WITH UPR IMPULSE SHOULD PROMOTE DEVELOPMENT OF
SCTD INTENSE AFTN/EVE STORMS FROM SE NM SEWD INTO THE PERMIAN
BASIN...THE TRANS-PECOS...AND WRN PORTIONS OF THE EDWARDS PLATEAU IN
TX. OTHER STORMS LIKELY WILL FORM FARTHER N ACROSS ERN NM AND W
TX...IN PART ALONG OUTFLOW ASSOCIATED WITH ELEVATED CONVECTION NOW
OVER PORTIONS OF THE TX/OK PANHANDLES AND NW OK.

GIVEN THE DEGREE OF INSTABILITY...40 KT WLY 500 MB FLOW ATOP 25+ KT
SLY 850 MB WINDS WILL BE SUFFICIENT FOR SUPERCELLS WITH VERY LARGE
HAIL...LOCALLY DMGG WIND...AND TORNADOES IN FAR SE NM AND SW TX. THE
LATTER RISK SHOULD BE GREATEST DURING THE EARLY STAGES OF STORM
DEVELOPMENT...BEFORE ACTIVITY EVOLVES INTO ESE-MOVING LARGE
CLUSTERS. HOWEVER...A NON-ZERO TORNADO THREAT ALSO COULD PERSIST
INTO THE EVE AS LLJ DIURNALLY STRENGTHENS AND INTENSIFIES
CIRCULATIONS WITH RESIDUAL EMBEDDED SUPERCELL STRUCTURES.

FARTHER N AND E...LARGER TEMP-DEWPOINTS SPREADS/COMPARATIVELY DRIER
LOW-LVL ENVIRONMENT SUGGEST A PREDOMINANT MULTICELL MODE WITH STORMS
LIKELY FORMING WITH SFC HEATING AND UPLIFT ALONG OUTFLOW BOUNDARIES
FROM ELEVATED STORMS ACROSS WRN/NRN TX AND OK. NEVERTHELESS...AMPLE
BUOYANCY AND SHEAR WILL EXIST FOR SVR HAIL/LOCALLY DMGG WIND AS A
SEPARATE CLUSTER OR TWO OF STORMS EVOLVES OVER THIS REGION...AND
PERSISTS INTO THE NGT.

...CNTRL LKS/MID OH VLY AFTN/EVE...
WEAK COLD FRONT AND DCVA ON LEADING EDGE OF PROGRESSIVE UPR IMPULSE
SHOULD FOSTER DEVELOPMENT OF A BAND OR TWO OF BROKEN SHOWERS/STORMS
LATER TODAY FROM CNTRL/ERN LWR MI SSW INTO ERN IND/WRN OH. SFC
HEATING COUPLED WITH MID-60S F SFC DEWPOINTS...500 MB TEMPS AROUND
MINUS 12C...AND 30-40 KT UNIDIRECTIONAL SW FLOW APPEAR FAVORABLE FOR
MULTICELL CLUSTERS WITH SMALL BOWS. THESE MAY PRODUCE LOCALLY DMGG
WIND/MARGINALLY SVR HAIL BEFORE WEAKENING DURING THE EVE.

...ERN CAROLINAS AFTN/EVE...
ALTHOUGH BONNIE HAS WEAKENED IN THE LAST 12-18 HRS...BELT OF
ENHANCED /25 KT/ SSELY 850-700 MB FLOW ON ERN SIDE OF SYSTEM WILL
SPREAD INLAND ACROSS FAR ERN SC AND S CNTRL/SE NC TODAY. AT THE SAME
TIME...PRECIP SHIELD ON EDGE OF BONNIE HAS FOSTERED DEVELOPMENT OF A
DAMMING-TYPE BOUNDARY EXTENDING NEWD FROM NEAR FLO ACROSS THE NC
SAND HILLS INTO E CNTRL NC. WHILE MODEST STRENGTH OF CIRCULATION OF
BONNIE WILL LIMIT HODOGRAPH SIZE...SOMEWHAT ENHANCED LOW-LVL SRH
WILL EXIST NEAR THE BOUNDARY...WHERE LIGHT SFC WINDS WILL REMAIN
BACKED TO ENELY. WITH SFC HEATING DESTABILIZING THE LWR
LVLS...CANNOT ENTIRELY RULE OUT THE POTENTIAL FOR A BRIEF TORNADO OR
TWO ALONG THE BOUNDARY THIS AFTN/EVE...BUT OVERALL THREAT SHOULD
REMAIN LOW/ISOLD.

..CORFIDI/COOK.. 05/29/2016

$$



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