SPC AC 101943
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0143 PM CST WED MAR 10 2010
VALID 102000Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE ERN PARTS OF THE SRN
PLAINS...OZARKS...THE MID-LWR MS RVR VLY AND THE GULF COAST...
CHANGES TO PREV OUTLOOK:
1/ ADJUST SLIGHT/SVR PROBABILITIES ALONG WESTERN EDGE IN THE PLAINS
2/ EXTEND SLIGHT/SVR PROBABILITIES EWD IN THE GULF CST STATES
...SRN PLAINS TO OZARKS/ARKLAMISS...
996 MB LOW WAS BEGINNING TO CONSOLIDATE NEAR/NW OF KOKC AT 19Z WITH
A DRYLINE QUICKLY TRANSLATING ENE INTO CNTRL/SCNTRL OK...THEN
TRAILING SSW INTO SCNTRL TX ALONG I-35. TO THE E...SOME IMPROVEMENT
IN BOUNDARY LAYER MOISTURE HAS TAKEN PLACE...WITH MORE SUBSTANTIAL
THETA-E EXPECTED TO ARRIVE ACROSS THE AR OZARKS AND MID-SOUTH YET
THIS EVENING.
LEADING BAND OF MORNING ASCENT/CONVECTION HAS COMPLICATED MATTERS
SOMEWHAT. EXPECT DCVA AND DRYLINE CIRCULATION WILL BECOME ALIGNED
ABOUT THE TIME EXISTING STORMS REACH THE MORE ROBUST THETA-E AXIS
ALONG THE OK/AR BORDER AFTER 21Z. A SUBSEQUENT INCREASE IN STORM
INTENSITY/NUMBER SHOULD ENSUE WITH UPSCALE GROWTH INTO A FORCED
SQLN. STRONGER STORMS SHOULD EVOLVE WITHIN/ALONG NRN EDGE OF BETTER
MOISTURE RETURN...NAMELY OVER THE AR OZARKS INTO THE MID-SOUTH.
MORE ISOLD VARIETY STORMS WILL THEN BUILD SSW ALONG THE DRYLINE INTO
ERN TX AND LA THROUGH THIS EVENING. EMBEDDED LEWPS/BOWS AND
OCCASIONAL SUPERCELL STRUCTURES CAN BE EXPECTED WITH LARGE HAIL AND
DMGG WINDS. TORNADO POTENTIAL WILL BE HIGHEST FROM THE AR
OZARKS/MID-SOUTH SWD INTO PARTS OF THE ARKLAMISS AS SRN EDGE OF
STORMS DEVELOPS ALONG NRN RETURN OF COMPARATIVELY RICH MOISTURE.
TO THE N AND NW...NRN PORTION OF ANY FORCED SQLN WILL DEVELOP NNE
THROUGH MO/SERN KS AND REACH THE MID-MS RVR VLY OVERNIGHT WITH
SPORADIC DMGG WIND GUSTS/HAIL. MEANWHILE...STRONG ASCENT AND STEEP
LAPSE RATE ENVIRONMENT MAY YIELD ISOLD LOW-TOPPED STRONG STORMS
ACROSS CNTRL/NCNTRL OK LATE THIS AFTN WITH POSSIBLE HAIL.
...GULF CST STATES...
MODEST UPGLIDE CONTINUES ALONG SSWLY BRANCH OF THE LLJ FROM SRN MS
INTO CNTRL/SRN AL AT MID-AFTN. 18Z SLIDELL SOUNDING EXHIBITED
LITTLE INHIBITION...A MODESTLY MOIST BOUNDARY LAYER AND MID-LVL
LAPSE RATES IN EXCESS OF 8 DEG C PER KM. RESULTANT MLCAPE OF 1500
J/KG AND DIFLUENT AIR MASS DOWNSTREAM FROM THE OK UPR LOW WILL BE
FAVORABLE FOR TSTMS TO BACKBUILD WSW INTO SRN LA THROUGH THE
NIGHT...THEN TRAIN ENE TOWARD CNTRL AL.
SWLY FLOW OF 30-35 KTS AT 1 KM WILL CONTINUE TO BE SUFFICIENT FOR
LLVL STORM ROTATION...AND SHOULD BE AUGMENTED BY AMBIENT SHEAR ALONG
THE NW-SE ORIENTED BAROCLINIC ZONE FROM NRN MS INTO CNTRL/SRN AL.
IMPROVING BOUNDARY LAYER MOISTURE AND MAGNITUDE OF LAPSE RATES
SUGGEST THAT SUPERCELLS WITH LARGE HAIL WILL BE LIKELY. DMGG WIND
GUSTS AND TORNADOES WILL BE RISKS... PARTICULARLY WITH THE SFC-BASED
STORMS ALONG/S OF THE FRONT.
..RACY.. 03/10/2010
.PREV DISCUSSION... /ISSUED 1027 AM CST WED MAR 10 2010/
...SYNOPSIS...
MOISTURE RETURN APPEARS TO BE THE PRIMARY LIMITATION ON UPGRADING TO
A GREATER RISK FOR TODAY AS THE VIGOROUS UPPER LOW NOW TX PANHANDLE
TRACKS NEWD ACROSS OK TO VICINITY MKC BY 12Z THU.
STRONG MID LEVEL JET MAX OF 80-90KT ACCOMPANIES UPPER LOW ACROSS ERN
OK INTO SRN MO/NRN AR THIS EVENING. VERY STRONG MID/UPPER LEVEL JET
STREAKS MOVING EWD ACROSS NRN GULF OF MEXICO WILL PROVIDE SHEAR AND
UPPER DIVERGENCE LOWER MS VALLEY THRU THE PERIOD ENHANCING SEVERE
POTENTIAL IN THE DEEPER MOISTURE RETURN THIS AREA.
COMPLEX RAPIDLY EVOLVING SEVERE SCENARIO AS LOW LEVEL MOISTURE
QUICKLY RETURNS AHEAD OF THE ONGOING LINE OF THUNDERSTORMS NCENTRAL
TX. STEEP/COOL MID LEVEL LAPSE RATES HAVE SPREAD EWD ACROSS THE
PLAINS AND LOWER MS VALLEY IN ADVANCE OF THE UPPER
SYSTEM...INCREASING POTENTIAL FOR SURFACE BASED STORMS ACROSS MUCH
OF LOWER MS VALLEY THIS AFTERNOON.
...ERN SRN PLAINS INTO MID MS VALLEY INCLUDING MO OZARKS...
SUFFICIENT LOW LEVEL MOISTURE EXPECTED TO BE INTO SRN MO PRIOR TO
THE ARRIVAL OF THE VIGOROUS UPPER VORT/WIND MAX TO SUPPORT
DEVELOPMENT OF A STRONGLY FORCED SQUALL LINE. WITH THE SURFACE LOW
NOW N OF SPS DEEPENING NEWD ACROSS OK DURING AFTERNOON...SEVERE
THUNDERSTORMS EXPECTED TO DEVELOP ERN OK AND THEN MOVE RAPIDLY NEWD
WITH DAMAGING WINDS THE PRIMARY THREAT. HAVE INCREASED THE WIND
POTENTIAL INTO SRN MO/NRN AR AREA. AN UPGRADE MAY BE JUSTIFIED THE
SAME AREA IN AFTERNOON UPDATE IF MOISTURE/INSTABILITY CAN RETURN
MORE THAN CURRENTLY EXPECTED.
ADDITIONALLY GIVEN THE STEEP LAPSE RATES AND STRONG
SHEAR...SUPERCELLS ARE LIKELY BOTH WITH AND AHEAD OF THE SQUALL
LINE. WITH THE COOL/STEEP LAPSE RATES AND MLCAPE UP TO 1000 J/KG
LARGE HAIL WILL BE LIKELY WITH ANY SUPERCELL ALONG WITH A TORNADO
POTENTIAL.
...LWR MS VALLEY...
MOISTURE CONTINUES TO DEEPEN IN STRONG LOW LEVEL FLOW ACROSS LOWER
MS VALLEY AHEAD OF COLD FRONT CENTRAL TX. WITH STEEP MID LEVEL
LAPSE RATES...7-8C/KM...OVERSPREADING THE AREA...CONDITIONS ARE NOW
FAVORABLE FOR SEVERE THUNDERSTORMS TO DEVELOP THIS AFTERNOON AS
CONVECTIVE INHIBITION QUICKLY WEAKENS.
WITH 30-35KT LOW LEVEL JET AND INCREASING DEEP LAYER SHEAR THRU THE
DAY...ENVIRONMENT WILL BECOME FAVORABLE FOR SUPERCELL DEVELOPMENT.
WITH THE BROAD LARGE SCALE ASCENT IN EXIT REGION OF UPPER JET ACROSS
NRN GULF DISCRETE STORM ORGANIZATION IS LIKELY ALONG WITH TORNADO
POTENTIAL. GIVEN MLCAPES ABOVE 1000 J/KG AND THE STEEP MID LEVEL
LAPSE RATES LARGE HAIL ALSO LIKELY WITH ANY STRONG
UPDRAFT...PARTICULARLY SUPERCELLS.
TORNADO THREAT MAY INCREASE TONIGHT CENTRAL GULF COASTAL AREAS.
HERE...INTENSIFICATION OF THE LOW-LEVEL FLOW AHEAD OF A VORT MAX
MOVING ENEWD ACROSS THE NRN GULF DURING THE EVENING/OVERNIGHT WILL
LIKELY SUPPORT A FURTHER INCREASE IN STORMS ACROSS THIS REGION.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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