Jim Martin Posted March 13, 2016 Author Share Posted March 13, 2016 0z 4k NAM down in Southeastern Arkansas for Sunday Evening. Link to comment Share on other sites More sharing options...
andyhb Posted March 13, 2016 Share Posted March 13, 2016 HRRR out to 16z SUN more or less lined up with the 00z 4km NAM. The general model agreement has been very solid, but now we'll see if the storm mode is as discrete/isolated as the models suggest. I suspect this could get upgraded to ENH risk, as mentioned before, a narrow significant hail probability zone may be added in AR. I think there's a decent shot we get a 10% tor in the D1 here as well. Both instability and shear would support a rather elevated tornado threat (although SRH in the lowest km is a bit weak initially). Link to comment Share on other sites More sharing options...
Chinook Posted March 13, 2016 Share Posted March 13, 2016 30% hatched hail risk, 5% tornado risk, and 15% wind risk for: Little Rock, AR...North Little Rock, AR...Pine Bluff, AR...Conway, AR...Hot Springs, AR.. Link to comment Share on other sites More sharing options...
JasonOH Posted March 13, 2016 Share Posted March 13, 2016 The HRRRX appears to show 2 lines of convection that come through. The first is definitely supercells, then it wants to increase CAPE behind it, and have this second group of storms come through. I'm not convinced the atmosphere will recover well enough for supercells, so I would expect a second line to be linear or multicellular. Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 Nice little compact intense system on water vapor..TOR probs increase to 10% on the 12z outlook fog should burn off soon over AR there still may be stratus though Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 AY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1124 AM CDT SUN MAR 13 2016 VALID 131630Z - 141200Z ...THERE IS AN ENH RISK OF SVR TSTMS OVER PARTS OF AR AND EXTREME NORTHWEST MS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE LOWER MS VALLEY... ...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE LOWER MS VALLEY... ..SUMMARY SCATTERED SEVERE STORMS ARE LIKELY FROM SOUTHEASTERN OKLAHOMA ACROSS CENTRAL AND SOUTHERN ARKANSAS THIS AFTERNOON AND EVENING. SUPERCELLS WITH A FEW TORNADOES...LARGE HAIL...AND DAMAGING GUSTS ARE EXPECTED. ..ARKLATEX INTO LOWER/MID MS VALLEY MORNING VISIBLE SATELLITE IMAGERY SHOWS CLEARING SKIES ACROSS THE ARKLATEX AND LOWER MS VALLEY THIS MORNING...HELPING TO WARM/DESTABILIZE THE REGION. A COMPACT SURFACE LOW IS ANALYZED OVER SOUTHERN OK. THIS LOW WILL TRACK EASTWARD INTO AR THIS EVENING...WITH STRONG SOUTHERLY LOW LEVEL WINDS TO THE EAST OF THE LOW DRAWING 60S DEWPOINTS NORTHWARD INTO PARTS OF AR/TN/MS. THIS WILL ALSO CONTRIBUTE TO INCREASING INSTABILITY...LEADING TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. PRESENT INDICATIONS ARE THAT STORMS WILL INTENSIFY BY MID AFTERNOON OVER PARTS OF WESTERN/CENTRAL AR AHEAD OF AN APPROACHING UPPER TROUGH...AND NEAR THE SURFACE LOW/COLD FRONT. FORECAST SOUNDINGS SUGGEST THE COMBINATION OF STEEP MID LEVEL LAPSE RATES...INCREASING VERTICAL SHEAR...AND SUFFICIENT LOW LEVEL MOISTURE WILL POSE A RISK OF SUPERCELL STORMS CAPABLE OF VERY LARGE HAIL. A CONSENSUS OF 12Z CAM SOLUTIONS SUGGEST A CORRIDOR OF GREATER CONCERN FOR MORE INTENSE STORMS AND TORNADOES WILL DEVELOP OVER SOUTHEAST AR AND EXTREME NORTHWEST MS. THIS AREA HAS BEEN ADDED TO THE ENHANCED RISK...AND A SIGNIFICANT TORNADO RISK AREA HAS BEEN INCLUDED. STORMS WILL LIKELY LOSE INTENSITY A FEW HOURS AFTER SUNSET AS THEY TRACK ACROSS NORTHERN MS AND WEST TN. ..HART/MOSIER.. 03/13/2016 Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 ESOSCALE DISCUSSION 0201 NWS STORM PREDICTION CENTER NORMAN OK 1235 PM CDT SUN MAR 13 2016 AREAS AFFECTED...ERN OK/WRN AR CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 131735Z - 131830Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...THUNDERSTORMS ARE EXPECTED TO DEVELOP SOON ACROSS ECNTRL/SERN OK. LARGE HAIL...AND A FEW TORNADOES ARE THE PRIMARY THREATS. WW WILL LIKELY BE REQUIRED SOON. DISCUSSION...EXIT REGION OF UPPER JET IS SHIFTING ACROSS OK TOWARD WRN AR. COMPACT CYCLONE WITH WELL-DEFINED DRY SLOT HAS DEVELOPED OVER SCNTRL OK. BOUNDARY LAYER LAPSE RATES ARE STEEPENING ACROSS SCNTRL OK WHERE SFC-3KM LAPSE RATES ARE NOW IN EXCESS OF 8 C/KM. CU FIELD IS EXPANDING IN AREAL COVERAGE IMMEDIATELY AHEAD OF SFC LOW OVER PONTOTOC COUNTY AND ROBUST VERTICAL UPDRAFTS SHOULD MATURE INTO TSTMS OVER THE NEXT 1-2 HOURS. SUPERCELLS ARE EXPECTED AND LARGE HAIL IS LIKELY. IN ADDITION...A FEW TORNADOES CAN BE EXPECTED. Link to comment Share on other sites More sharing options...
Indystorm Posted March 13, 2016 Share Posted March 13, 2016 Tor watch now issued for se OK east to Fort Smith until 7 CDT. Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 ESOSCALE DISCUSSION 0202 NWS STORM PREDICTION CENTER NORMAN OK 0101 PM CDT SUN MAR 13 2016 AREAS AFFECTED...FAR NE TX...CNTRL/SRN AR...NE/N-CNTRL LA CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 131801Z - 131930Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...FAST-MOVING SUPERCELL TSTMS ARE EXPECTED TO DEVELOP AROUND 20-21Z. ALL SVR THREATS ARE POSSIBLE INCLUDING VERY LARGE HAIL /GREATER THAN 2 INCHES/ AND A STRONG TORNADO OR TWO. TORNADO WATCH LIKELY. DISCUSSION...INCREASING CU FIELD ACROSS NE TX IS INDICATIVE OF INCREASED FORCING FOR ASCENT AMIDST THE DESTABILIZING AIRMASS AHEAD OF THE COMPACT SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW OVER CNTRL OK. AREAS DOWNSTREAM OF THIS CU FIELD WILL CONTINUE TO DESTABILIZE UNDER ABUNDANT SUNSHINE AND INCREASING LOW-LEVEL MOISTURE WITH CONVECTIVE INITIATION EXPECTED BEFORE 20Z. ONCE INITIATION OCCURS...STRONGLY SHEARED ENVIRONMENT /EFFECTIVE BULK SHEAR LIKELY ABOVE 50 KT/ AND MODEST INSTABILITY /MLCAPE AROUND 1000 J PER KG/ WILL SUPPORT FAST-MOVING SUPERCELLS WITH ALL SVR THREATS POSSIBLE...INCLUDING HAIL GREATER THAN 2 INCHES AND/OR STRONG TORNADOES. A TORNADO WATCH WILL LIKELY BE NEEDED TO COVER THE POTENTIAL SVR THREAT. Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 Everything seems to be coming together perfectly ..time of day. time of speed max, sun coming out, cool pocket aloft, and all the water laying around AR and LA isn't exactly hurting low level moisture Link to comment Share on other sites More sharing options...
Indystorm Posted March 13, 2016 Share Posted March 13, 2016 Dews in the upper 50's throughout the affected areas are a bit lower than I'd like, but low 60 dew points show up just to the south and will probably advect northward as the day progresses. Link to comment Share on other sites More sharing options...
JasonOH Posted March 13, 2016 Share Posted March 13, 2016 Tornado watch for the southern 3/4 of AR, some far NW LA, and a couple TX and OK counties. 70/40 tor probs, 90/50 hail. Link to comment Share on other sites More sharing options...
SmokeEater Posted March 13, 2016 Share Posted March 13, 2016 Discrete cells starting to fire in SE OK, moving NE towards Ft. Smith. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 13, 2016 Share Posted March 13, 2016 New day 1 outlook didn't change much. A few strong tornadoes are "expected", per SPC. Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 could be a 500mb "cold core" outbreak with low topped mini supercells....over eastern OK/western AR Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 13, 2016 Share Posted March 13, 2016 Those cells near the OK/AR boarder are looking set to become low topped supercells. Cell near Heavener already has a decent meso Sent from my SM-G925V using Tapatalk Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 13, 2016 Share Posted March 13, 2016 Forecast sounding in the vicinity of the supercell on the AR/LA border Link to comment Share on other sites More sharing options...
andyhb Posted March 13, 2016 Share Posted March 13, 2016 Forecast sounding in the vicinity of the supercell on the AR/LA border I don't think the dewpoints are going to be that high. Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 13, 2016 Share Posted March 13, 2016 I think I'm gonna have to agree with JJ998 here and say this turns out to be a rather excellent example of a cold core ULL tornado outbreak. There is some great research done by Earl Barker on previous outbreaks. Sent from my SM-G925V using Tapatalk Link to comment Share on other sites More sharing options...
SmokeEater Posted March 13, 2016 Share Posted March 13, 2016 Severe warned cell near Heavener, OK has that look. Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 13, 2016 Share Posted March 13, 2016 Severe warned cell near Heavener, OK has that look.Yeah, rotation increasing on the higher tilts...Thats gonna be in the Little Rock burbs soon Sent from my SM-G925V using Tapatalk Link to comment Share on other sites More sharing options...
SmokeEater Posted March 13, 2016 Share Posted March 13, 2016 Cell near Gillham, AR just went TW'd. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 13, 2016 Share Posted March 13, 2016 I don't think the dewpoints are going to be that high. Even if it is, 60+ dew point is going to make for a very nasty environment with those wind profiles Link to comment Share on other sites More sharing options...
thewxmann Posted March 13, 2016 Share Posted March 13, 2016 I don't think the dewpoints are going to be that high. Yeah the HRRR has been overforecasting dewpoints by about 3-6 degrees F, which is interesting given the moist ground in place. But yeah, the dewpoints over southern AR and northern LA are only in the 50s right now. Bases are going to be sky high until later in the evening. Link to comment Share on other sites More sharing options...
andyhb Posted March 13, 2016 Share Posted March 13, 2016 Yeah the HRRR has been overforecasting dewpoints by about 3-6 degrees F, which is interesting given the moist ground in place. But yeah, the dewpoints over southern AR and northern LA are only in the 50s right now. Bases are going to be sky high until later in the evening. No they aren't, the LCLs are maxing out in the 1000 m range via mesoanalysis. Also the further ENE they move, the temperatures become more manageable. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 13, 2016 Share Posted March 13, 2016 Yeah the HRRR has been overforecasting dewpoints by about 3-6 degrees F, which is interesting given the moist ground in place. But yeah, the dewpoints over southern AR and northern LA are only in the 50s right now. Bases are going to be sky high until later in the evening. Observations show 59-60 dew points in N LA. With the system progressing and nocturnal LLJ coming in, I don't think HRRR is that far off. I can see 62 dew point in the aforementioned area. Also, by the time the storms move into this area, nocturnal cooling will have been happening for hours... so I don't think the LCL is going to be that high by the time the storms move into that area. Link to comment Share on other sites More sharing options...
andyhb Posted March 13, 2016 Share Posted March 13, 2016 Note, the obs. at ADF is obviously off. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 13, 2016 Share Posted March 13, 2016 Bunch of chasers in the area Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 0343 PM TORNADO 10 N DIERKS 34.27N 94.02W 03/13/2016 HOWARD AR TRAINED SPOTTER SPOTTED BRIEF ROPE TORNADO Link to comment Share on other sites More sharing options...
janetjanet998 Posted March 13, 2016 Share Posted March 13, 2016 ULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE LITTLE ROCK AR 356 PM CDT SUN MAR 13 2016 THE NATIONAL WEATHER SERVICE IN LITTLE ROCK HAS ISSUED A * TORNADO WARNING FOR... SOUTHWESTERN MONTGOMERY COUNTY IN WESTERN ARKANSAS... EAST CENTRAL POLK COUNTY IN WESTERN ARKANSAS... * UNTIL 415 PM CDT * AT 356 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO WAS LOCATED OVER BARD SPRINGS RECREATION AREA...OR NEAR UMPIRE...MOVING NORTHEAST AT 40 MPH. HAZARD...TORNADO AND PING PONG BALL SIZE HAIL. SOURCE...RADAR INDICATED ROTATION. Link to comment Share on other sites More sharing options...
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