DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 151945
SWODY1
SPC AC 151943

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0243 PM CDT MON JUL 15 2013

VALID 152000Z - 161200Z

...THERE IS A SLGT RISK OF SVR TSTMS ERN MT THROUGH WRN ND...

...DISCUSSION...

CURRENT FORECAST STILL APPEARS ON TRACK. EXPECT PRIMARY SEVERE
THREAT TO EVOLVE FROM ERN MT THROUGH WRN ND LATE THIS AFTERNOON INTO
THE EARLY EVENING WITH STORMS DEVELOPING ON COLD FRONT AND ON THE
HIGHER TERRAIN. OTHERWISE...HAVE INCLUDED A 5% PROBABILITY LINE FROM
THE LOWER-MID MS VALLEY INTO ERN KS FOR POSSIBILITY OF STRONG WIND
GUSTS WITH SCATTERED STORMS DEVELOPING WITHIN BELT OF 30-40 KT SELY
WINDS ALOFT AND AN UNSTABLE BOUNDARY LAYER.

...ERN TX...SWRN LA AND SWRN AR...

REFERENCE SWOMCD 1400.

..DIAL.. 07/15/2013

.PREV DISCUSSION... /ISSUED 1129 AM CDT MON JUL 15 2013/

...SYNOPSIS...
STRONG ANTICYCLONE WILL REMAIN ANCHORED OVER THE UPR OH VLY THROUGH
TUE AS SRN PLNS UPR LOW CONTINUES SLOWLY WWD AND SLIGHTLY WEAKENS. A
RIDGE WILL PERSIST N AND W OF THE LOW...EXTENDING FROM AZ THROUGH
THE GRT BASIN TO THE NRN PLNS. N OF THE RIDGE...A BELT OF FAST WSW
FLOW WILL CONTINUE FROM SRN BC TO NRN ONT. A FAIRLY STRONG IMPULSE
IN THIS FLOW...NOW ENTERING SRN AB...WILL REACH SW SK THIS EVE AND
WRN MB EARLY TUE.

SFC LOW ASSOCIATED WITH THE AB IMPULSE WILL TRACK E/NE ALONG MARKED
FRONTAL ZONE OVER SRN SK LATER TODAY. THE FRONT WILL SETTLE SE INTO
NRN MT THIS EVE/EARLY TUE AS AN ATTENDANT LEE TROUGH DEEPENS OVER
THE ERN PART OF THAT STATE. ELSEWHERE...SFC FEATURES WILL REMAIN
WEAK. LARGE-SCALE COOL-AIR DOME ASSOCIATED WITH SRN PLNS UPR LOW
WILL EXPAND FARTHER W INTO NM AND S ACROSS S TX...WHILE ITS ERN
FRINGE ERODES OVER ERN OK AND THE ARKLATEX.

CONDITIONS SHOULD BECOME FAVORABLE FOR THE DEVELOPMENT OF SVR TSTMS
ALONG THE COLD FRONT AND LEE TROUGH IN SK AND NE MT LATER
TODAY...AND SOME OF THIS ACTIVITY COULD AFFECT ADJACENT PARTS OF
WY/ND. OTHERWISE...RELATIVELY WEAK LAPSE RATES AND/OR MODEST SHEAR
SHOULD MINIMIZE SVR THREAT ELSEWHERE IN THE NATION.

...NRN HIGH PLNS THIS AFTN THROUGH TNGT...
STRONG SFC HEATING WILL OCCUR AHEAD OF COLD FRONT AND DEEPENING LEE
TROUGH OVER NRN/ERN MT NWD INTO SRN SK. APPRECIABLE LOW-LVL MOISTURE
INFLOW ALSO SHOULD PERSIST...ESPECIALLY OVER FAR ERN AND NERN MT.
SFC DEWPOINTS IN THAT AREA LIKELY WILL AVERAGE IN THE LOW 60S
F...AND CONTRIBUTE TO MLCAPE AOA 2000 J/KG GIVEN CONTINUING PRESENCE
OF DEEP EML.

ALTHOUGH THE STRONGEST FORCING FOR ASCENT WITH AB UPR IMPULSE WILL
REMAIN N OF THE INTERNATIONAL BORDER...SUFFICIENT UPR
DIVERGENCE/DCVA SHOULD OVERSPREAD PARTS OF MT TO HELP INITIATE
STORMS THERE GIVEN LOW-LVL UPLIFT ALONG COLD FRONT AND/OR LEE
TROUGH. THIS ACTIVITY SHOULD MOVE/DEVELOP E/NE INTO WRN AND NRN ND
THIS EVE AS THE FRONT/TROUGH CONTINUE ENEWD.

35-40 KT WSWLY 500 MB FLOW ON SRN FRINGE OF UPR IMPULSE WILL PROVIDE
AMPLE DEEP SHEAR FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL AND DMGG
WIND. ALTHOUGH SIZABLE SFC T/TD SPREADS WILL EXIST OVER PARTS OF
MT...SATELLITE SUGGESTS THAT SCTD TO BKN CLOUDS MAY LINGER OVER THE
FAR NE PART OF THE STATE EWD INTO ND. COUPLED WITH SLIGHTLY BACKED
SFC FLOW IN THIS REGION...SOME RISK ALSO WILL EXIST FOR TORNADOES.

MERGING STORM OUTFLOWS AND THE CONTINUED ENE ADVANCE OF UPR IMPULSE
SHOULD SUPPORT EVOLUTION INTO A SMALL MCS BY MID EVE...EXTENDING THE
THREAT FOR SVR WIND/HAIL FARTHER E/NE INTO ND.

SWD ALONG LEE TROUGH INTO WY...THE SVR RISK APPEARS MORE
MARGINAL/CONDITIONAL GIVEN WEAKER FORCING FOR ASCENT...WEAKER
SHEAR...AND MORE LIMITED MOISTURE. NEVERTHELESS...TERRAIN
CIRCULATIONS IN THE PRESENCE OF DEEP EML AND SUFFICIENT MOISTURE FOR
STORMS SUGGEST A POTENTIAL FOR SVR WIND GUSTS AND POSSIBLY HAIL WITH
ANY STORMS THAT DO FORM IN THE MORE DEEPLY MIXED ENVIRONMENT.

...S TX THIS AFTN THROUGH TNGT...
SFC HEATING AND CONTINUED MOISTURE INFLOW WILL YIELD MODEST LOW-LVL
DESTABILIZATION ALONG DIFFUSE OUTFLOW BOUNDARY DRIFTING SLOWLY S
ACROSS S CNTRL TX TODAY. BUT WWD MOTION OF OK UPR LOW WILL DO LITTLE
TO ERODE WARM MID-LVL TEMPS ACROSS REGION. COUPLED WITH ABUNDANT
CLOUDS SPREADING SWD WITH NNWLY UPR-LVL FLOW AND THE ABSENCE OF
STRONG WLYS IN THE MID-LVLS...PROSPECTS FOR SUSTAINED SVR STORMS
APPEAR MINIMAL. HOWEVER...WITH HIGH PW AND 25 KT SELY LOW-LVL FLOW
PERSISTING OVER REGION...POTENTIAL WILL EXIST FOR AN OCCASIONAL
STORM OR TWO POSING A TRANSIENT RISK FOR A LOCALLY DMGG WIND GUST OR
BRIEF TORNADO.

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