Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 041301
SWODY1
SPC AC 041258

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 AM CDT SAT JUL 04 2015

VALID 041300Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN AND CNTRL
PLNS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL GULF
CST STATES...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE NRN HIGH PLNS TO THE
SRN PLNS AND FROM THE LWR MS VLY TO THE CAROLINA CST...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE GRT BASIN...

...SUMMARY...
A FEW SEVERE STORMS WITH LARGE HAIL...DAMAGING WINDS...AND POSSIBLY
A TORNADO ARE EXPECTED OVER PARTS OF THE NORTHERN AND CENTRAL PLAINS
LATE THIS AFTERNOON AND EVENING. STORMS CAPABLE OF LOCALLY DAMAGING
WIND AND HEAVY RAIN ARE EXPECTED OVER CENTRAL GULF COAST STATES.
MORE ISOLATED STRONG TO SEVERE STORMS WILL AFFECT THE SOUTHERN
PLAINS...GEORGIA...THE CAROLINAS...AND THE GREAT BASIN.

...SYNOPTIC SETUP...
GRT BASIN/SRN RCKYS RIDGE/ERN U.S. TROUGH PATTERN WILL PREVAIL
THROUGH SUN. MODERATE WLY FLOW WITH SEVERAL EMBEDDED DISTURBANCES
WILL CONTINUE OVER THE NRN RCKYS AND NRN/CNTRL PLNS...ON NE SIDE OF
THE RIDGE. ONE NOTABLE DISTURBANCE WITHIN THE ERN TROUGH...NOW
ENTERING NW AR...WILL TRACK E ACROSS THE LWR MS/LWR TN VLYS
TNGT/EARLY SUN...WHILE SEVERAL WEAKER IMPULSES PRECEDE IT ACROSS THE
SRN APPALACHIANS/CAROLINAS.

VERY MOIST AIR /PW 1.75-2.00 INCHES/ WILL PERSIST FROM THE SRN PLNS
E/NE TO THE MID/S ATLANTIC CST. SUFFICIENT MOISTURE FOR STORMS ALSO
WILL BE PRESENT OVER THE CNTRL AND NRN PLNS...WHERE PW WILL REMAIN
AOA 1.25 INCHES.

...CNTRL GULF CST STATES TO CAROLINA CST THIS AFTN...
MORNING RAOB AND VWP DATA SAMPLE SEASONABLY STRONG /30-40 KT/ WSWLY
MID-LVL FLOW OVER REGION...ASSOCIATED IN PART WITH AR UPR IMPULSE.
COMBINATION OF MODEST SFC HEATING...INCREASING LARGE-SCALE ASCENT
WITH UPR DISTURBANCE...AND HI PW MAY FOSTER DEVELOPMENT OF
OCCASIONAL BOWING SEGMENTS THIS AFTN WITH A RISK FOR LOCALLY DMGG
WIND...MAINLY WITH NEW STORMS FORMING ALONG AND S OF EXISTING W-E
OUTFLOW BOUNDARY THAT ATTM EXTENDS FROM FAR NRN LA TO W CNTRL GA.
MORE ISOLD STRONG GUSTS MAY PERSIST INTO TNGT AS EMBEDDED BOWING
SEGMENTS CONTINUE E INTO GA/SC.  FARTHER E...A MORE CONDITIONAL RISK
FOR LOCALLY DMGG WIND MAY EVOLVE OVER PARTS OF SC AND ERN NC THIS
AFTN...WHERE CONVERGENCE WILL BE LIMITED BUT SOMEWHAT STRONGER
HEATING WILL OCCUR BENEATH LINGERING AXIS OF STRONGER FLOW
ASSOCIATED WITH SFC WAVE/UPR IMPULSE DEPARTING THE NC CST.

...NRN/CNTRL PLNS THIS AFTN INTO TNGT...
STRONG HEATING AMIDST AMPLE MOISTURE WILL PROMOTE SUBSTANTIAL
DESTABILIZATION TODAY ALONG AND AHEAD OF LEE TROUGH OVER THE
NRN/CNTRL HIGH PLNS. MORE MODEST DESTABILIZATION IS EXPECTED OVER
THE NRN HIGH PLNS...ALONG WEAK COLD FRONT ASSOCIATED WITH WRN CANADA
UPR LOW.

A FEW STORMS MAY FORM TOWARD MIDDAY...ASSOCIATED WITH LEAD UPR
IMPULSE NOW OVER THE WRN DAKOTAS. ADDITIONAL DEVELOPMENT SHOULD
OCCUR LATER THIS AFTN SWD ACROSS WRN NEB INTO NW KS...WITH SECONDARY
DISTURBANCE TRACKING SEWD FROM MT. STORMS ALSO MAY FORM NEAR THE
BLACK HILLS...AND ALONG THE COLD FRONT IN NRN/ERN MT. SOME OF THE
DAKOTAS/NEB/NW KS CONVECTION MAY EVOLVE INTO DISCRETE SUPERCELLS
CAPABLE OF LARGE HAIL...DMGG WINDS...AND A
TORNADO OR TWO. THE DAKOTAS/NEB/KS ACTIVITY SHOULD MERGE INTO ONE OR
TWO SMALL MCSS THAT PERSIST INTO EARLY SUN.

...SRN PLNS THIS AFTN/EVE...
WEAK NW/SE FRONT AND RELATED CONVECTIVE OUTFLOW BOUNDARIES WILL ONCE
AGAIN SERVE TO FOCUS AFTN/EVE STORM DEVELOPMENT OVER PARTS OF OK AND
TX. LARGE-SCALE FORCING FOR ASCENT WILL REMAIN WEAK...AND THE 850 MB
FLOW SLIGHTLY DIVERGENT. NEVERTHELESS...PRESENCE OF VERY
MOIST/UNSTABLE LOW-LVL AIR BENEATH RELATIVELY COOL MID-LVL
TEMPERATURES...AND MODEST BUT VERTICALLY-VEERING WIND
PROFILES...WILL YIELD AN ENVIRONMENT CONDITIONALLY FAVORABLE FOR
ISOLD TO PERHAPS WDLY SCTD STRONG UPDRAFTS. A SUPERCELL OR TWO COULD
FORM AND...GIVEN STRENGTH OF BUOYANCY...THESE WOULD BE CAPABLE OF
SVR HAIL/WIND.

...GRT BASIN THIS AFTN/EVE...
SFC HEATING AND ASCENT ASSOCIATED WITH AN IMPULSE MOVING NNW AROUND
WRN SIDE OF UPR RIDGE SHOULD YIELD FAIRLY WIDESPREAD DIURNAL STORMS
OVER MUCH OF CNTRL AND NRN NV. COUPLED WITH STEEP LOW TO MID-LVL
LAPSE RATES...ISOLD STRONG TO SVR WIND GUSTS AND/OR SMALL HAIL MAY
OCCUR AS THE ACTIVITY ORGANIZES INTO SMALL...NWD-MOVING CLUSTERS.

..CORFIDI/MARSH.. 07/04/2015




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