SmokeEater Posted March 10, 2012 Share Posted March 10, 2012 If there is more clearing tomorrow then thought, there could be trouble. SREF indicating 200-300 helicity over the area tomorrow. Discuss. DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1121 AM CST SAT MAR 10 2012 VALID 111200Z - 121200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ARKLATEX INTO THE OZARKS... ...SYNOPSIS... AN UPPER LOW WILL EJECT NEWD ACROSS THE SRN AND CNTRL PLAINS INTO THE MID TO UPPER MS VALLEY THROUGH THE PERIOD. MID TO UPPER LEVEL WIND FIELDS WILL INCREASE OVER MUCH OF THE REGION WITH THE ENTRANCE REGION OF THE UPPER JET MOVING ACROSS AR AND MO DURING THE AFTERNOON AND EVENING. AT THE SURFACE...PRESSURES WILL FALL BUT A CONSOLIDATED SURFACE LOW IS NOT FORECAST TO DEVELOP. NEITHER WILL THERE BE A STRONG COLD FRONT...BUT SUBTLE CONFLUENCE WILL EXIST ACROSS THE ENTIRE WARM SECTOR. BROAD SWLY 850 MB FLOW ON THE ORDER OF 40-50 KT WILL HELP BRING MOISTURE RAPIDLY NWD WITH BOUNDARY LAYER DEWPOINTS INTO THE LOWER 60S INTO CNTRL AR BY AFTERNOON. ...ARKLATEX INTO THE OZARKS... WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS WILL BE ONGOING OVER MUCH OF ERN TX...OK...KS...SWRN MO AND WRN AR SUN MORNING AS MOISTURE STREAMS NWD IN THE WARM CONVEYOR. AS THE UPPER TROUGH AND ASSOCIATED HEIGHT FALLS DEVELOP NEWD...THE WRN EDGE OF THE EARLY ACTIVITY SHOULD SHARPEN AND CONSOLIDATE INTO AN ORGANIZED BAND OF THUNDERSTORMS...WITH INCREASING INTENSITY WITH TIME....BEGINNING OVER FAR ERN OK AND NERN TX. SHEAR PROFILES WILL STRENGTHEN OVER AR WITH THE LOW LEVEL JET EXCEEDING 50 KT BY 00Z. FORECAST HODOGRAPHS ARE LARGE AND SMOOTH IN THE LOW LEVELS AND WOULD BE FAVORABLE FOR TORNADIC SUPERCELLS. MAIN MITIGATING FACTORS TO A MORE SUBSTANTIAL THREAT ARE SUBTLE WARM SECTOR FORCING...ONGOING AREAS OF RAIN AND SOMEWHAT MARGINAL LEVELS OF INSTABILITY...AT LEAST FOR STRONG TORNADOES. WITH NO CAPPING ACROSS THE WARM SECTOR AND INCREASING DEWPOINTS BY AFTERNOON...SW-NE ORIENTED BANDS OF DEEP CONVECTION MAY ALSO FORM AHEAD OF THE MAIN LINE OF STORMS. SINCE THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE LOCATION OF THE BEST INSTABILITY AND SHEAR...HAVE ADDED A SMALL 30 PERCENT AREA ACROSS CNTRL AR. IN ADDITION TO TORNADOES...DAMAGING WINDS WITH SMALL BOWING LINE SEGMENTS ALSO APPEAR LIKELY. ..JEWELL.. 03/10/2012 Link to comment Share on other sites More sharing options...
andyhb Posted March 11, 2012 Share Posted March 11, 2012 Monday looks interesting too across the GL/OV, although that will be on the other board. Link to comment Share on other sites More sharing options...
thunderman Posted March 11, 2012 Share Posted March 11, 2012 Somewhat anxious to see what the 00z runs hold ... especially the NSSL-WRF. Link to comment Share on other sites More sharing options...
SquatchinNY Posted March 11, 2012 Share Posted March 11, 2012 DO you have a link to the NSSL-WRF? Link to comment Share on other sites More sharing options...
David Reimer Posted March 11, 2012 Share Posted March 11, 2012 About time someone started a thread on this. I've been watching tomorrow's setup since the 12Z runs on Friday. There wasn't much attention given to tomorrow by the chase community until SPC placed a 30% Severe risk with sexy wording. Once that happened, it was like there was a shirt-less woman in the room and all the chasers starting going nuts over tomorrow. Personally, I see some potential for tomorrow's setup, but I also see a great deal of bust potential. I'm going to emulate one of my elders and discuss this in a bulletin type format. PROS: Good speed/directional shear, dewpoint values AOA 65°F, Storm motions shouldn't be 80 MPH (Something to look forward to, right?) CONS: Widespread warm sector precipitation will limit instability, models seem to be fluctuating on amounts/location of highest instability, embedded supercells in a linear complex, issues with high-precipitation storm mode. I just saved myself two paragraphs worth of text, sweet! I will be out chasing tomorrow, but I do have my concerns. That said, directional shear looks decent and instability amounts are right on the border. Considering it's only a three hour drive out east from Dallas, I'm gonna take the bait and head on out to Arkansas tomorrow. We'll see what the 0Z model suite ends up doing. Link to comment Share on other sites More sharing options...
JoMo Posted March 11, 2012 Share Posted March 11, 2012 DO you have a link to the NSSL-WRF? http://www.nssl.noaa.gov/wrf/ 00z SPC WRF while we're there: http://www.emc.ncep.noaa.gov/mmb/mpyle/spcprod/00/ Link to comment Share on other sites More sharing options...
Indystorm Posted March 11, 2012 Share Posted March 11, 2012 The amount of clearing and northward advance of moisture seem to be the big variables at present in Arkansas...typical for early spring set ups like this. Link to comment Share on other sites More sharing options...
Chicago Storm Posted March 11, 2012 Share Posted March 11, 2012 Soundings look decent, but my biggest issue is with crap-vection. Right now from LZK and on south across the southern 1/2 of the currecnt SPC 30% risk looks best. Link to comment Share on other sites More sharing options...
David Reimer Posted March 11, 2012 Share Posted March 11, 2012 Soundings look decent, but my biggest issue is with crap-vection. Right now from LZK and on south across the southern 1/2 of the currecnt SPC 30% risk looks best. Agreed. I'm liking the area between Interstate 20 in Northern Louisiana to around Highway 82 in Southern Arkansas. I'm planning on getting out there by about 1-2 PM and wait for the main show to start. Link to comment Share on other sites More sharing options...
Chicago Storm Posted March 11, 2012 Share Posted March 11, 2012 Agreed. I'm liking the area between Interstate 20 in Northern Louisiana to around Highway 82 in Southern Arkansas. I'm planning on getting out there by about 1-2 PM and wait for the main show to start. Good luck. Looks like several of the short term runs like that area. Link to comment Share on other sites More sharing options...
andyhb Posted March 11, 2012 Share Posted March 11, 2012 DAY 1 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK 1159 PM CST SAT MAR 10 2012 VALID 111200Z - 121200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OZARKS REGION SWD INTO THE SABINE RIVER VALLEY... ...SYNOPSIS... AN UPPER LOW INITIALLY SHIFTING ACROSS THE TX/OK PANHANDLE AREA IS PROGGED TO CONTINUE NEWD ACROSS THE PLAINS...REACHING THE IA/SRN MN VICINITY BY THE END OF THE PERIOD. MEANWHILE...A SHORT-WAVE TROUGH IS PROGGED TO CROSS THE PAC NW AND MOVE INTO THE CANADIAN ROCKIES THROUGH THE SECOND HALF OF THE PERIOD. AT THE SURFACE...A COLD FRONT IS PROGGED TO CONTINUE MOVING ACROSS THE NWRN CONUS...WHILE A LEE TROUGH LINGERS OVER THE HIGH PLAINS AND WEAK WARM FRONT LIFTS NWD ACROSS THE S CENTRAL PART OF THE COUNTRY. ELSEWHERE...HIGH PRESSURE WILL PREVAIL OVER THE ERN THIRD OF THE CONUS THROUGH THE PERIOD. ...MO/AR/E TX/LA... WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS ARE PROGGED TO BE ONGOING AT THE START OF THE PERIOD...FROM PARTS OF ERN KS/OK/ERN TX EWD INTO THE OZARKS REGION WITHIN BROAD ZONE OF LOW-LEVEL WARM ADVECTION. WITH CLOUDS AND PRECIPITATION WIDESPREAD...WEAK LAPSE RATES AND VERY LIMITED POTENTIAL FOR APPRECIABLE HEATING SHOULD HINDER OVERALL DESTABILIZATION POTENTIAL ACROSS THE SLIGHT RISK AREA. INCREASING LARGE-SCALE ASCENT ASSOCIATED WITH A PASSING VORT LOBE SE OF THE MAIN LOW DURING THE AFTERNOON SHOULD MAINTAIN AN ENVIRONMENT SUPPORTIVE OF MAINTAINING THE CLOUDS/PRECIPITATION THROUGH PEAK HEATING HOURS. HAVING SAID THAT...INCREASING/VEERING FLOW WITH HEIGHT THROUGH THE LOWER HALF OF THE TROPOSPHERE WILL RESULT IN DEEP-LAYER SHEAR SUPPORTIVE OF ORGANIZED/ROTATING STORMS...AS WELL AS LOW-LEVEL SHEAR SUPPORTIVE OF TORNADO POTENTIAL. OVERALL...THIS POTENTIAL SHOULD REMAIN MODULATED BY THE WEAK LAPSE RATES/VERY LIMITED INSTABILITY...BUT A FEW STRONGER CELLS MAY EVOLVE DURING THE AFTERNOON -- IN WHICH CASE THE POTENTIAL FOR LOCALLY DAMAGING WINDS AND A COUPLE OF TORNADOES WOULD BE REALIZED. WHILE A CONDITIONAL SCENARIO...THREAT WARRANTS CONTINUATION OF SLIGHT RISK AREA. THREAT SHOULD CONTINUE INTO THE EVENING...THOUGH SOME DECREASE IN THE ALREADY-LIMITED INSTABILITY SUGGESTS THREAT SHOULD WANE SOME OVERNIGHT. ..GOSS.. 03/11/2012 Link to comment Share on other sites More sharing options...
andyhb Posted March 11, 2012 Share Posted March 11, 2012 Latest SPC WRF (12z run from earlier today) fires several discrete supercells across AR tomorrow ahead of the line... http://www.emc.ncep....yle/spcprod/12/ Link to comment Share on other sites More sharing options...
Jim Martin Posted March 11, 2012 Share Posted March 11, 2012 For what it is worth. The H triple R projected radar image for Arkansas and Louisiana at 5pm cdt this evening. Link to comment Share on other sites More sharing options...
Indystorm Posted March 11, 2012 Share Posted March 11, 2012 Meso discussion out now for possible watch for se TX and Houston area later this morning as gulf moisture returns northward. Wil only prime the pump for action in Arkansas later today. Link to comment Share on other sites More sharing options...
Srain Posted March 11, 2012 Share Posted March 11, 2012 Meso discussion out now for possible watch for se TX and Houston area later this morning as gulf moisture returns northward. Wil only prime the pump for action in Arkansas later today. Surface low near Matagorda Bay and retreating frontal boundary are setting the stage for an active afternoon. The approaching S/W and upper trough will add to instability and veering winds should increase the threat for rotating cells later this morning from the Houston Area extending NNE into AR. Link to comment Share on other sites More sharing options...
thunderman Posted March 11, 2012 Share Posted March 11, 2012 Good luck Reimer! Link to comment Share on other sites More sharing options...
Srain Posted March 11, 2012 Share Posted March 11, 2012 MESOSCALE DISCUSSION 0241 NWS STORM PREDICTION CENTER NORMAN OK 1131 AM CDT SUN MAR 11 2012 AREAS AFFECTED...ERN TX INTO NWRN LA CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 111631Z - 111800Z RECENT TRENDS HAVE BEEN FOR STORMS MOVING INTO SERN TX TO INCREASE IN INTENSITY. THIS ACTIVITY COULD BECOME CAPABLE OF PRODUCING ISOLATED DAMAGING WIND AND PERHAPS A COUPLE OF TORNADOES. CONVECTIVE TRENDS ARE BEING MONITORED FOR A POSSIBLE WW. TREND HAS BEEN FOR STORMS DEVELOPING ALONG PRE-FRONTAL CONVERGENCE BAND FROM WEST OF THE HOUSTON METRO AREA NWD TO NEAR HUNTSVILLE TO INTENSIFY AND BECOME A LITTLE BETTER ORGANIZED AS LINES. THE RECENT INTENSIFICATION APPEARS TO BE OCCURRING AS THE CONVERGENCE BAND BEGINS TO INTERACT WITH THE THETA-E AXIS WITH DEWPOINTS IN THE UPPER 60S AND TEMPERATURES IN THE LOW 70S SUPPORTING 500-800 J/KG MLCAPE OVER SERN TX. THE ATMOSPHERE SHOULD DESTABILIZE SLOWLY NWD WITH TIME. VWP DATA INDICATE 0-1 KM STORM RELATIVE HELICITY ON THE ORDER OF 150-200 M2/S2 AND 0-6 KM SHEAR FROM 35-45 KT. TENDENCY WILL BE FOR LOW LEVEL FLOW TO GRADUALLY DECREASE ACROSS SERN TX AS THE LLJ SHIFTS NWD INTO THE LOWER MS VALLEY. HOWEVER...VERTICAL WIND PROFILES WILL REMAIN SUFFICIENT FOR EMBEDDED ORGANIZED STORM STRUCTURES INCLUDING SUPERCELLS AND BOWING SEGMENTS NEXT FEW HOURS. ..DIAL.. 03/11/2012 ATTN...WFO...LCH...SHV...HGX... Link to comment Share on other sites More sharing options...
Chicago Storm Posted March 11, 2012 Share Posted March 11, 2012 Risk across the northern and central 2/3 of the slight risk area is pretty much dead. Looks like any decent threat will be limited to central and southern Louisiana, south of I-20 Link to comment Share on other sites More sharing options...
Indystorm Posted March 11, 2012 Share Posted March 11, 2012 Extensive cloud cover and precip shield over Arkansas, but dews are slowly progressing northward which SPC expects to continue. My guess is that better opportunity for svr would be in the eastern portion of the slight risk near the delta where current observations are partly sunny, in addition to central and southern Louisiana. Link to comment Share on other sites More sharing options...
Jim Martin Posted March 11, 2012 Share Posted March 11, 2012 This is a recent radar image from the Fort Polk, Louisiana NEXRAD. Note the common-head feature here when the storm was tornado-warned. Link to comment Share on other sites More sharing options...
SouthernNJ Posted March 11, 2012 Share Posted March 11, 2012 A couple of mesocyclones have prompted a few TOR/SVR's today, but nothing spectacular. The storm near I-49 looks the best to me at this time. Link to comment Share on other sites More sharing options...
andyhb Posted March 12, 2012 Share Posted March 12, 2012 Nasty discrete supercell in Southern LA right now, tornado warned. Link to comment Share on other sites More sharing options...
David Reimer Posted March 12, 2012 Share Posted March 12, 2012 Chase summary and photo gallery from my chase yesterday in Louisiana. http://texasstormchasers.com/?p=6649 Link to comment Share on other sites More sharing options...
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