Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 281644
SWODY1
SPC AC 281642

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1142 AM CDT SAT MAY 28 2016

VALID 281630Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL PART OF THE
MID/UPR MS VLY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF S CNTRL TX...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE MID/UPR MS
VLY...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF CNTRL/SRN CNTRL
TX...

...THERE IS A MRGL RISK OF SVR TSTMS ALONG A SMALL PART OF THE S
ATLANTIC CST...

...SUMMARY...
SCATTERED THUNDERSTORMS...SOME SEVERE...ARE EXPECTED THIS AFTERNOON
AND EVENING OVER PARTS OF SOUTH CENTRAL AND SOUTHWEST TEXAS.  OTHER
STRONG TO SEVERE AFTERNOON AND EVENING STORMS WILL OCCUR OVER PARTS
OF THE MID AND UPPER MISSISSIPPI VALLEY. ISOLATED SEVERE STORMS WILL
BE POSSIBLE TONIGHT AND EARLY SUNDAY ALONG THE SOUTH CAROLINA AND
SOUTHERN NORTH CAROLINA COAST.

...SYNOPTIC SETUP...
NEB/IA SHORTWAVE TROUGH EXPECTED TO FURTHER WEAKEN AS IT CONTINUES
SLOWLY ENEWD...REACHING SW WI EARLY SUN. IN ITS WAKE...WEAK
SHORTWAVE RIDGING WILL PREVAIL OVER THE SRN AND CNTRL
PLNS...DOWNSTREAM FROM SRN STREAM LOW APPROACHING THE SRN CA CST.
OVER THE SOUTHEAST...WITH RIDGE REMAINING QSTNRY OFF THE
MID-ATLANTIC CST...TD #2 EXPECTED TO CONTINUE NWWD...POSSIBLY
DECELERATING WITH TIME PER NHC.

FEATURES WILL REMAIN WEAK AT LWR LVLS. A WEAK LOW WILL TRACK NE
ACROSS NW IA ATTENDANT TO NEB-IA UPR VORT. THE LOW SHOULD TURN MORE
ENEWD ALONG STALLED FRONT OVER SRN MN/CNTRL WI TNGT. ACROSS THE SRN
PLNS...RELAXATION OF LOW-LVL DRYING/COOLING IN WAKE OF NEB-IA
SYSTEM...AND STRENGTHENING OF LEE TROUGH DOWNSTREAM FROM E PAC
LOW...WILL BACK LOW-LVL FLOW TO SELY...ALLOWING MOISTURE TO RETURN
NWWD ACROSS SW AND WRN TX.

...MID/UPR MS VLY TODAY...
POCKETS OF MODERATE WARM SECTOR HEATING WILL OCCUR TODAY OVER
NRN/ERN IA AND ADJACENT NW IL/SW WI AND FAR SRN MN...S OF STALLED
FRONT IN MN/WI...AND W OF RESIDUAL TSTM DEBRIS IN IL. SATELLITE
SUGGESTS THAT ASCENT WITH WRN IA VORT LOBE WILL OVERSPREAD NRN AND
ERN IA FOLLOWING MAX HEATING...WITH ASSOCIATED 500 MB TEMPS AOB
MINUS 14C CONTRIBUTING TO AREAL DESTABILIZATION. ALTHOUGH GRADUAL
WEAKENING OF UPR SYSTEM WILL KEEP MEAN FLOW COMPARATIVELY MODEST
RELATIVE TO RECENT DAYS...RESIDUAL BAND OF 40+ KT SWLY 700-500 MB
FLOW ON E SIDE OF VORT LOBE WILL SUPPLY AMPLE DEEP SHEAR FOR SHORT
LINES OF SUSTAINED/ORGANIZED STORMS WITH HAIL/LOCALLY DMGG WIND.
AND...ALTHOUGH WIND PROFILES WILL ONCE AGAIN EXHIBIT VERTICAL
VEER-BACK PATTERNS...WITH SFC DEWPOINTS IN THE MID 60S F AND
ENHANCED LOW-LVL DIRECTIONAL SHEAR NEAR STALLED FRONT...CANNOT RULE
OUT THE RISK OF A TORNADO OR TWO GIVEN SOME POTENTIAL FOR FAVORABLE
STORM-BOUNDARY INTERACTION. THE SVR THREAT SHOULD DIMINISH AFTER
SUNSET.

...S CNTRL/SW TX TO SW KS/WRN OK THIS AFTN INTO TNGT...
STRONG SFC HEATING AND INFLOW OF RICH MOISTURE RETURNING NWWD ACROSS
THE BIG BEND REGION AND HILL COUNTRY WILL YIELD CONSIDERABLE
SFC-BASED CAPE /VALUES AOA 4000 J PER KG/ ACROSS S CNTRL TX THIS
AFTN. ALTHOUGH WEAK SHORTWAVE RIDGING WILL PREVAIL...SATELLITE
SUGGESTS PRESENCE OF WEAK DISTURBANCES EMANATING NRN CHIHUAHUA
THAT...COUPLED WITH TERRAIN CIRCULATIONS AND/OR LOCALIZED ASCENT
ALONG RESIDUAL OUTFLOW BOUNDARIES FROM YESTERDAY`S MCS...COULD BOOST
PARCELS TO THEIR LFCS. GIVEN STRENGTH OF BUOYANCY...IF EML CAP IS
INDEED BREACHED...25-30 KT WLY MID-LVL FLOW WILL BE SUFFICIENT FOR
HP-TYPE SUPERCELLS WITH A RISK FOR VERY LARGE HAIL...LOCALLY DMGG
WIND AND PERHAPS A TORNADO. THESE MAY MERGE INTO A SLOWLY-MOVING
CLUSTER OVER THE HILL COUNTRY TNGT.

FARTHER N...CANNOT RULE OUT THE POSSIBILITY FOR AN ISOLD STORM OR
TWO WITH LARGE HAIL FORMING IN NOCTURNALLY-STRENGTHENED WAA/MOISTURE
TRANSPORT ZONE OVER THE TX/OK PANHANDLES AND ADJACENT PARTS OF OK/SW
KS EARLY SUN. THE COVERAGE OF ANY SUCH ACTIVITY...HOWEVER...APPEARS
TOO LOW TO WARRANT ADDITION OF PROBABILITIES ATTM.

...CSTL CAROLINAS/TD 2 TNGT/EARLY SUN...
TD 2 IS EXPECTED TO CONTINUE GENERALLY NWWD THROUGH THE PERIOD
...GIVEN STRENGTH/ORIENTATION OF RIDGE OFF THE MID-ATLANTIC CST.
SATELLITE/LIGHTNING DATA AND COMPARATIVELY COOL MID-LVL TEMPS
SUGGEST THAT AN ENVELOPE OF SUFFICIENTLY BUOYANT AIR WILL REMAIN
PRESENT ON THE NWRN EDGE OF THE SYSTEM TO SUPPORT ADDITIONAL
SEMI-DISCRETE STORM DEVELOPMENT. WITH SYSTEM NOT EXPECTED TO
APPRECIABLY DEEPEN /PER NHC/...HODOGRAPHS LIKELY WILL REMAIN FAIRLY
SMALL. NEVERTHELESS...PRESENCE OF ENHANCED LOW-LVL DIRECTIONAL SHEAR
INVOF DISCRETE CELLS SUGGESTS A NON-ZERO BRIEF TORNADO RISK ALONG
PARTS OF THE SC AND SRN NC CSTS LATE TNGT AND EARLY SUN.

..CORFIDI/COOK.. 05/28/2016

$$



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