Disc Posted December 25, 2012 Share Posted December 25, 2012 DISCRETE SUPERCELLS CAPABLE OF ALL THREATS OF SEVERE WEATHER /INCLUDING THE POTENTIAL FOR LONG-TRACKED TORNADOES/ MAY BE POSSIBLE AS THE AFOREMENTIONED MID-UPPER LEVEL JET APPROACHES...SUBSEQUENTLY STRENGTHENING DEEP LAYER SHEAR PROFILES AND PROMOTING STRONG ROTATION. VISIBLE IMAGERY SUGGESTS CLEARING MAY OCCUR OVER PORTIONS OF SE TX...CNTRL/SRN LA/MS/AL...WHERE THE GREATEST POTENTIAL SURFACE-BASED DESTABILIZATION AND CONSEQUENTLY TORNADIC POTENTIAL WILL EXIST LATER THIS MORNING INTO THE AFTERNOON. HOWEVER...IMPLIED SUBSIDENCE /DEMARCATED BY SIGNIFICANT DRYING ON WV IMAGERY OVER THE WRN GULF/ MAY VERY TEMPORARILY DELAY THE DEVELOPMENT IN DISCRETE SUPERCELLS ACROSS THE WARM SECTOR UNTIL FORCING FOR ASCENT QUICKLY ARRIVES WITH THE E TX SHORT WAVE. AS SUCH...THE EXPECTED LIMITED TEMPORAL THREAT OF DISCRETE CELLS WILL PRECLUDE AN UPGRADE TO HIGH RISK ATTM...THOUGH THE CATEGORICAL THREAT WILL BE REEVALUATED AT 20Z. Link to comment Share on other sites More sharing options...
CUmet Posted December 25, 2012 Share Posted December 25, 2012 WAA along and south of the warm front has really facilitated strong convection across MS/AL this morning. Soundings from LCH show that LFC values have risen substantially in the wake of BL saturation while Td's have cooled to the low 60s. This might help curb the tornado threat somewhat as the surface cyclone is moving about an hour faster than what 00Z models like the NAM had been forecasting last night. Basically, the window for substantial atmospheric destabilization in advance of the big round later this afternoon is looking to be somewhat protracted based upon latest events. I'm not sure what you mean. The dewpoint in Lake Charles is up to 66 at the latest hourly ob. Although dewpoints in the area should remain stagnant or even drop a couple degrees due to boundary layer mixing, the temps should rise well into the mid 70s given the clear skies in the warm sector. The only reason why the LFC was so high on the 12z sounding was because of two reasons: 1) it was taken at 12z, so the boundary layer wasn't well mixed and 2) the mid levels were quite warm at 12z, but this should cool as the trough approaches from the west. If anything, I'm more concerned now given that the warm sector is considerably clearer than I had anticipated yesterday. Link to comment Share on other sites More sharing options...
tornadotony Posted December 25, 2012 Share Posted December 25, 2012 And if my eyes aren't deceiving me each one seems to have some rotation in it according to my radar scope. Quite ominous. Yes. We saw very similar signatures for the 3 long-lived tornadic supercells that hit northern Illinois on 5 June 2010, when we had a series of these smaller, rotating cells coalesce into larger supercells. There are already signs of that happening at this time, and the environment ahead of them is quite supportive of strong to violent tornadoes. Link to comment Share on other sites More sharing options...
jerseystorm Posted December 25, 2012 Share Posted December 25, 2012 This Storm Means Business. http://hint.fm/wind/ Link to comment Share on other sites More sharing options...
SquatchinNY Posted December 25, 2012 Share Posted December 25, 2012 TORwarn up for one of the cells! Link to comment Share on other sites More sharing options...
Ed Lizard Posted December 25, 2012 Share Posted December 25, 2012 BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 1039 AM CST TUE DEC 25 2012 THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A * TORNADO WARNING FOR... EXTREME NORTHEASTERN HARRIS COUNTY IN SOUTHEAST TEXAS... SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST TEXAS... NORTHWESTERN LIBERTY COUNTY IN SOUTHEAST TEXAS... * UNTIL 1115 AM CST * AT 1037 AM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED NEAR ROMAN FOREST...OR 8 MILES NORTHEAST OF KINGWOOD...AND MOVING EAST AT 55 MPH. * LOCATIONS IMPACTED INCLUDE... PATTON VILLAGE...WOODBRANCH...ROMAN FOREST...SPLENDORA...PLUM GROVE AND DAYTON LAKES. Link to comment Share on other sites More sharing options...
SquatchinNY Posted December 25, 2012 Share Posted December 25, 2012 Has rotation per Radarscope. Plum Grove should take cover, storm may skirt them. Link to comment Share on other sites More sharing options...
gkrangers Posted December 25, 2012 Share Posted December 25, 2012 Concerned about the storm over downtown Houston, as well. Link to comment Share on other sites More sharing options...
SquatchinNY Posted December 25, 2012 Share Posted December 25, 2012 I see two possible couplets on torwarned storm. One to the SSW of Plum Grove, and one to the ESE. Link to comment Share on other sites More sharing options...
Ground Scouring Posted December 25, 2012 Share Posted December 25, 2012 I'm not sure what you mean. The dewpoint in Lake Charles is up to 66 at the latest hourly ob. Although dewpoints in the area should remain stagnant or even drop a couple degrees due to boundary layer mixing, the temps should rise well into the mid 70s given the clear skies in the warm sector. The only reason why the LFC was so high on the 12z sounding was because of two reasons: 1) it was taken at 12z, so the boundary layer wasn't well mixed and 2) the mid levels were quite warm at 12z, but this should cool as the trough approaches from the west. If anything, I'm more concerned now given that the warm sector is considerably clearer than I had anticipated yesterday. You know, you are right, so I should stick with my original thoughts. I am on a learning curve here. Recent satellite imagery shows very pronounced clearing all over the warm sector from LA into the southern two-thirds of MS, and it does appear to be occurring a bit more rapidly when what I envisioned based upon model data. I think SPC may have a High Risk at 20Z. (Edit: Dacula beat me to the punch; see below.) Link to comment Share on other sites More sharing options...
DaculaWeather Posted December 25, 2012 Share Posted December 25, 2012 According to James Spann, SPC is considering a High Risk upgrade this afternoon. Link to comment Share on other sites More sharing options...
Ellinwood Posted December 25, 2012 Share Posted December 25, 2012 According to James Spann, SPC is considering a High Risk upgrade this afternoon. DISCRETE SUPERCELLS CAPABLE OF ALL THREATS OF SEVERE WEATHER /INCLUDING THE POTENTIAL FOR LONG-TRACKED TORNADOES/ MAY BE POSSIBLE AS THE AFOREMENTIONED MID-UPPER LEVEL JET APPROACHES...SUBSEQUENTLY STRENGTHENING DEEP LAYER SHEAR PROFILES AND PROMOTING STRONG ROTATION. VISIBLE IMAGERY SUGGESTS CLEARING MAY OCCUR OVER PORTIONS OF SE TX...CNTRL/SRN LA/MS/AL...WHERE THE GREATEST POTENTIAL SURFACE-BASED DESTABILIZATION AND CONSEQUENTLY TORNADIC POTENTIAL WILL EXIST LATER THIS MORNING INTO THE AFTERNOON. HOWEVER...IMPLIED SUBSIDENCE /DEMARCATED BY SIGNIFICANT DRYING ON WV IMAGERY OVER THE WRN GULF/ MAY VERY TEMPORARILY DELAY THE DEVELOPMENT IN DISCRETE SUPERCELLS ACROSS THE WARM SECTOR UNTIL FORCING FOR ASCENT QUICKLY ARRIVES WITH THE E TX SHORT WAVE. AS SUCH...THE EXPECTED LIMITED TEMPORAL THREAT OF DISCRETE CELLS WILL PRECLUDE AN UPGRADE TO HIGH RISK ATTM...THOUGH THE CATEGORICAL THREAT WILL BE REEVALUATED AT 20Z. Link to comment Share on other sites More sharing options...
Superstorm93 Posted December 25, 2012 Share Posted December 25, 2012 According to James Spann, SPC is considering a High Risk upgrade this afternoon. Was just posted in their last outlook THE EXPECTED LIMITED TEMPORAL THREAT OF DISCRETE CELLS WILL PRECLUDE AN UPGRADE TO HIGH RISK ATTM...THOUGH THE CATEGORICAL THREAT WILL BE REEVALUATED AT 20Z. Link to comment Share on other sites More sharing options...
Superstorm93 Posted December 25, 2012 Share Posted December 25, 2012 MESOSCALE DISCUSSION 2209 NWS STORM PREDICTION CENTER NORMAN OK 1102 AM CST TUE DEC 25 2012 AREAS AFFECTED...SWRN/W-CNTRL/S-CNTRL OK...WRN NORTH TX CONCERNING...BLIZZARD VALID 251702Z - 252100Z SUMMARY...BLIZZARD CONDITIONS ARE DEVELOPING ACROSS SWRN/W-CNTRL/S-CNTRL OK...AND WILL CONTINUE THROUGH AROUND 22-23Z. NLY WINDS OF 25-35 MPH WITH FREQUENT GUSTS OF 40-45 MPH WILL COMBINE WITH SNOWFALL RATES OF 1-1.5 IN/HR TO GENERATE NEAR-ZERO VISIBILITIES AND WHITEOUT CONDITIONS. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 A lot of damage reports coming in across the HGX forecast area. Many trees down and roofs off buildings mainly N of Metro Houston. I've had S winds gusting to 45+kts for at least 3 hours now. Link to comment Share on other sites More sharing options...
Ensō Posted December 25, 2012 Share Posted December 25, 2012 A lot of damage reports coming in across the HGX forecast area. Many trees down and roofs off buildings mainly N of Metro Houston. I've had S winds gusting to 45+kts for at least 3 hours now. Yikes, that'll do some damage. 1530 80 LOVELADY HOUSTON TX 3113 9545 LOVELADY FIRECHIEF REPORT WIND GUST OF 80 MPH (HGX) Link to comment Share on other sites More sharing options...
Superstorm93 Posted December 25, 2012 Share Posted December 25, 2012 850mb winds are cranking now. Lots of reports of non-thunderstorm wind damage coming in. Link to comment Share on other sites More sharing options...
DaculaWeather Posted December 25, 2012 Share Posted December 25, 2012 URGENT - WINTER WEATHER MESSAGE NATIONAL WEATHER SERVICE MEMPHIS TN 1110 AM CST TUE DEC 25 2012 ...BLIZZARD CONDITIONS EXPECTED TO IMPACT PARTS OF THE MIDSOUTH FROM LATE TODAY...THROUGH CHRISTMAS NIGHT AND INTO EARLY WEDNESDAY... .A STRONG UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY ACROSS TEXAS WILL TRACK INTO THE MIDSOUTH BY THIS EVENING. RAIN WILL SPREAD OVER MOST OF THE MIDSOUTH THIS AFTERNOON...POSSIBLY MIXED WITH SLEET AND SNOW ACROSS NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL. PRECIPITATION ACROSS NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL WILL CHANGE OVER TO ALL SNOW BY EARLY EVENING. PERIODS OF HEAVY SNOW WILL BE POSSIBLE DURING THE NIGHT. IN ADDITIONAL TO THE HEAVY SNOW...STRONG NORTH WINDS GUSTING UP TO 45 MPH ARE EXPECTED...CAUSING SEVERE REDUCTIONS IN VISIBILITIES...ALONG WITH BLOWING AND DRIFTING CONDITIONS. ARZ008-009-017-018-026>028-035-MOZ113-115-TNZ001-002-019-048- 260115- /O.CON.KMEG.BZ.W.0001.121225T2100Z-121226T1500Z/ RANDOLPH-CLAY-LAWRENCE-GREENE-CRAIGHEAD-POINSETT-MISSISSIPPI- CROSS-DUNKLIN-PEMISCOT-LAKE-OBION-DYER-LAUDERDALE- INCLUDING THE CITIES OF...WALNUT RIDGE...PARAGOULD...JONESBORO... HARRISBURG...BLYTHEVILLE...WYNNE...KENNETT...CARUTHERSVILLE... UNION CITY...DYERSBURG 1110 AM CST TUE DEC 25 2012 ...BLIZZARD WARNING REMAINS IN EFFECT FROM 3 PM THIS AFTERNOON TO 9 AM CST WEDNESDAY... * VISIBILITIES AT TIMES DOWN TO LESS THAN A QUARTER OF A MILE. * SNOW ACCUMULATIONS...6 TO 10 INCHES...WITH LOCALLY HIGHER AMOUNTS. * TIMING...RAIN WILL CHANGE OVER TO SNOW LATE THIS AFTERNOON AND INTO THE EARLY EVENING HOURS. SNOW WILL BECOME HEAVY AT TIMES TONIGHT. * WINDS...SUSTAINED WINDS AROUND 25 TO 30 MPH WITH GUSTS OF 35 TO 45 MPH. * IMPACTS...SNOW AND BLOWING SNOW WILL SIGNIFICANTLY REDUCE VISIBILITIES. TRAVEL WILL BECOME HAZARDOUS. .PRECAUTIONARY/PREPAREDNESS ACTIONS... A BLIZZARD WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE EXPECTED OR OCCURRING. FALLING AND BLOWING SNOW WITH STRONG WINDS AND POOR VISIBILITIES ARE LIKELY. THIS WILL LEAD TO WHITEOUT CONDITIONS...MAKING TRAVEL EXTREMELY DANGEROUS. DO NOT TRAVEL. IF YOU MUST TRAVEL...HAVE A WINTER SURVIVAL KIT WITH YOU. IF YOU GET STRANDED...STAY WITH YOUR VEHICLE. && $$ ARZ036-048-049-058-MSZ001-007-008-010-011-TNZ003-004-020-021- 049>051-088-089-260115- /O.CON.KMEG.WW.Y.0002.121226T0300Z-121226T1500Z/ CRITTENDEN-ST. FRANCIS-LEE AR-PHILLIPS-DESOTO-TUNICA-TATE-COAHOMA- QUITMAN-WEAKLEY-HENRY-GIBSON-CARROLL-TIPTON-HAYWOOD-CROCKETT- SHELBY-FAYETTE- INCLUDING THE CITIES OF...WEST MEMPHIS...FORREST CITY...HELENA... SOUTHAVEN...OLIVE BRANCH...TUNICA...CLARKSDALE...MARTIN... DRESDEN...PARIS...HUMBOLDT...MILAN...HUNTINGDON...COVINGTON... BARTLETT...GERMANTOWN...COLLIERVILLE...MEMPHIS...MILLINGTON... SOMERVILLE 1110 AM CST TUE DEC 25 2012 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 9 PM THIS EVENING TO 9 AM CST WEDNESDAY... * SNOW AND SLEET ACCUMULATIONS...SNOW ACCUMULATIONS OF ONE TO THREE INCHES WITH LOCALLY HIGHER AMOUNTS. A BRIEF MIXTURE OF ICE PELLETS...WITH ACCUMULATIONS OF LESS THAN A TENTH OF AN INCH WILL ALSO BE POSSIBLE. * TIMING...RAIN WILL CHANGE OVER TO SNOW AFTER MIDNIGHT AND CONTINUE THROUGH EARLY WEDNESDAY MORNING. * IMPACTS...TRAVEL WILL BECOME HAZARDOUS...ESPECIALLY ON SECONDARY ROADS BEGINNING LATE THIS EVENING THROUGH TOMORROW MORNING. GUSTY WINDS UP TO 40 MPH WILL ALSO REDUCE VISIBILITIES AT TIMES DOWN TO LESS THAN A HALF OF A MILE. .PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW AND SLEET WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS AND LIMITED VISIBILITIES FROM BLOWING SNOW. USE CAUTION WHEN TRAVELING...ESPECIALLY IN OPEN AREAS. && $$ SJM Link to comment Share on other sites More sharing options...
Disc Posted December 25, 2012 Share Posted December 25, 2012 Moderate risk for tomorrow in the Carolinas. DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1112 AM CST TUE DEC 25 2012 VALID 261200Z - 271200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER CENTRAL AND ERN PARTS OF THE CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS FROM NRN/CENTRAL FL AND SRN GA NWD INTO SRN VA... ...A SIGNIFICANT SEVERE WEATHER EPISODE IS POSSIBLE ON WEDNESDAY OVER PARTS OF THE CENTRAL AND ERN CAROLINAS... ...SYNOPSIS... PROGRESSIVE UPPER FLOW PATTERN IS FORECAST TO CONTINUE TOMORROW AS A VIGOROUS COLD UPPER LOW /CURRENTLY OVER THE SRN PLAINS/ IS FORECAST TO MOVE RAPIDLY FROM THE TN VALLEY TO THE SRN MIDDLE ATLANTIC REGION DURING THE PERIOD. VERY LARGE 12 HR 500 MB HEIGHT FALLS OF 180 M AND STRONG WINDS ALOFT WILL ACCOMPANY THIS SYSTEM...WITH 90-100 KT 500 MB WINDS AND 60-70 KT FLOW AT 850 MB. AT THE SURFACE...MODELS INDICATE THAT THE PRIMARY LOW WILL DEVELOP OVER NRN GA AND DEEPEN AS IT MOVES NEWD EAST OF THE APPALACHIANS...MOVING ACROSS THE NC PIEDMONT DURING THE LATE AFTERNOON/EVENING AND CONTINUING ACROSS THE DELMARVA REGION LATER AT NIGHT. A STRONG COLD FRONT EXTENDING SWD FROM THE LOW WILL SURGE EWD TOWARD THE ATLANTIC COAST AND SEWD ACROSS THE FL PENINSULA...MOVING OFFSHORE INTO THE ATLANTIC WATERS OVERNIGHT. A WARM FRONT EXTENDING FROM THE NC COAST SWWD ACROSS CENTRAL GA WILL GRADUALLY LIFT NWD...EXTENDING FROM NERN NC INTO THE PIEDMONT BY LATE AFTERNOON. THESE BOUNDARIES AND SURFACE LOW WILL PROVIDE THE PRIMARY LOW LEVEL FOCUSING MECHANISMS FOR STRONG/SEVERE THUNDERSTORM DEVELOPMENT. ...CENTRAL/ERN CAROLINAS... A STRONG/SEVERE BROKEN QLCS WITH EMBEDDED BOW ECHOES AND POSSIBLE SUPERCELLS/MESO-VORTICES IS EXPECTED TO BE ONGOING AT THE START OF THE PERIOD...EXTENDING FROM NRN GA SWD INTO THE GULF OF MEXICO SOUTH OF THE TLH. AS THE AFOREMENTIONED WARM FRONT LIFTS NWD...LOW LEVEL MOISTURE WILL INCREASE INLAND WITH LOW/MID 60S F SURFACE DEW POINTS SPREADING INTO THE WARM SECTOR. ALTHOUGH CLOUDS AND AREAS OF LIGHTER PRECIPITATION WILL INHIBIT DIABATIC HEATING...THE AIR MASS IS EXPECTED TO DESTABILIZE WITH MLCAPE REACHING 1000 J/KG IN PARTS OF THE WARM SECTOR. VERY STRONG DYNAMIC FORCING FOR LARGE SCALE ASCENT WITHIN THE LEFT EXIT REGION OF THE CYCLONIC UPPER LEVEL JET WILL OVERSPREAD THE WARM SECTOR DURING THE MORNING. THIS WILL ENHANCE CONVECTIVE STORM INTENSITY WITHIN THE QLCS AND SUPPORT ADDITIONAL INITIATION OF DISCRETE CELLS AND CLUSTERS IN THE WEAKLY CAPPED WARM SECTOR. VERY STRONG DEEP LAYER SHEAR OF 50-70 KT IN THE LOWEST 6 KM WILL BE SUPPORTIVE OF UPDRAFT ROTATION AND BOWING SEGMENTS CAPABLE OF PRODUCING MORE WIDESPREAD DAMAGING WIND GUSTS AND POTENTIAL FOR TORNADOES ALONG THE QLCS. GIVEN THE VERY STRONG LOW LEVEL SHEAR AND SRH /200-500 M2 PER S2 FOR RIGHT-MOVING SUPERCELLS/ AND EXPECTED RAPID STORM MOTION...THERE WILL ALSO BE POTENTIAL FOR SEVERAL LONG-TRACK STRONG TORNADOES ASSOCIATED WITH ANY DISCRETE PERSISTENT SUPERCELLS THAT MAY FORM THROUGH THE AFTERNOON AND EARLY EVENING. THE SEVERE THREAT WILL GRADUALLY END FROM THE WEST AS THE LOW AND COLD FRONT CONTINUE TO MOVE RAPIDLY NEWD/EWD THROUGH THE EVENING HOURS. ...GA SWD INTO NRN/CENTRAL FL A THREAT FOR DAMAGING WIND GUSTS AND ISOLATED HAIL WILL EXTEND SWD FROM PARTS OF SRN/ERN GA INTO NRN/CENTRAL FL AS THE LINE OF CONVECTION MOVES EWD DURING THE DAY. THE RISK IS EXPECTED TO GRADUALLY DIMINISH WITH SWD EXTENT AS THE PRIMARY DYNAMIC FORCING MOVES EWD/NEWD ACROSS THE CAROLINAS AND MIDDLE ATLANTIC REGION. ..WEISS.. 12/25/2012 Link to comment Share on other sites More sharing options...
Superstorm93 Posted December 25, 2012 Share Posted December 25, 2012 Details are very sketchy, but TWC is reporting a fatality from winds (thunderstorm?) in the Houston metro area. Link to comment Share on other sites More sharing options...
Isopycnic Posted December 25, 2012 Share Posted December 25, 2012 Details are very sketchy, but TWC is reporting a fatality from winds (thunderstorm?) in the Houston metro area. We've already heard of one weather-related fatality in northwest Harris County. It happened around 9:30am in the 17600 block of North Eldridge Parkway. Authorities say a young male driver heading down the street came across a fallen tree, and when he decided to move the broken limbs off the road, another tree snapped and fell on top of him. http://abclocal.go.com/ktrk/story?section=news/local&id=8931442 Link to comment Share on other sites More sharing options...
andyhb Posted December 25, 2012 Share Posted December 25, 2012 That's a lot of clearing in LA... And...oh boy...hello dry punch HOWEVER...IMPLIED SUBSIDENCE /DEMARCATED BY SIGNIFICANT DRYING ON WV IMAGERY OVER THE WRN GULF/ MAY VERY TEMPORARILY DELAY THE DEVELOPMENT IN DISCRETE SUPERCELLS ACROSS THE WARM SECTOR UNTIL FORCING FOR ASCENT QUICKLY ARRIVES WITH THE E TX SHORT WAVE. Link to comment Share on other sites More sharing options...
AgeeWx Posted December 25, 2012 Share Posted December 25, 2012 K Index bullseye in advance of the approaching line. Clearing should only increase the index. Link to comment Share on other sites More sharing options...
Amped Posted December 25, 2012 Share Posted December 25, 2012 The storms are linear at this point, the discrete cells ahead of the line are too tightly packed to produce long track tornadoes. HRRR keeps it this way. I am done rooting for tornadoes. Link to comment Share on other sites More sharing options...
Disc Posted December 25, 2012 Share Posted December 25, 2012 HOWEVER...IMPLIED SUBSIDENCE /DEMARCATED BY SIGNIFICANT DRYING ON WV IMAGERY OVER THE WRN GULF/ MAY VERY TEMPORARILY DELAY THE DEVELOPMENT IN DISCRETE SUPERCELLS ACROSS THE WARM SECTOR UNTIL FORCING FOR ASCENT QUICKLY ARRIVES WITH THE E TX SHORT WAVE. The storms are linear at this point, the discrete cells ahead of the line are too tightly packed to produce long track tornadoes. HRRR keeps it this way. I am done rooting for tornadoes. Link to comment Share on other sites More sharing options...
thewxmann Posted December 25, 2012 Share Posted December 25, 2012 HRRR is back up! EDIT: Doesn't really have a good handle on the linear nature of the convection right now though... Link to comment Share on other sites More sharing options...
andyhb Posted December 25, 2012 Share Posted December 25, 2012 Looks like we might have a PDS watch coming... A NEW TORNADO WATCH WILL BE NEEDED TO REPLACE CURRENT WW 692 PRIOR TO 19Z...WITH THE POTENTIAL FOR THIS NEW WW TO BE A PDS GIVEN A SIGNIFICANT INCREASE IN EFFECTIVE SRH THIS AFTERNOON AS THE LLJ STRENGTHENS ACROSS THE LOWER MS VALLEY. Link to comment Share on other sites More sharing options...
Amped Posted December 25, 2012 Share Posted December 25, 2012 really? Yeah, enough destruction after Sandy. Would rather just see snow. And yes still a number of tornados today. Line doesn't have a super discrete look to it though. HRRR could be wrong. Edit: NAM disagrees and makes the line discrete later. http://raleighwx.americanwx.com/models/nam4km/12zNAM4kmreflectivity_SE.html Link to comment Share on other sites More sharing options...
Superstorm93 Posted December 25, 2012 Share Posted December 25, 2012 MESOSCALE DISCUSSION 2210 NWS STORM PREDICTION CENTER NORMAN OK 1204 PM CST TUE DEC 25 2012 AREAS AFFECTED...E/SE TX AND CENTRAL/SRN LA CONCERNING...TORNADO WATCH 692...694... VALID 251804Z - 251930Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 692...694...CONTINUES. SUMMARY...TORNADO THREAT WILL CONTINUE TO INCREASE ACROSS SE TX INTO SWRN AND CENTRAL LA ACROSS WW 694...WITH A TORNADO POTENTIAL ALSO INTO THE FAR SRN EXTENT OF SVR WW 693. A NEW TORNADO WATCH WILL BE NEEDED TO REPLACE CURRENT WW 692 PRIOR TO 19Z...WITH THE POTENTIAL FOR THIS NEW WW TO BE A PDS GIVEN A SIGNIFICANT INCREASE IN EFFECTIVE SRH THIS AFTERNOON AS THE LLJ STRENGTHENS ACROSS THE LOWER MS VALLEY. DISCUSSION...LATE THIS MORNING...THERE HAS BEEN AN INCREASE IN CG LIGHTNING STRIKES ACROSS SE THROUGH EAST CENTRAL TX TO NWRN LA INVOF A SURFACE LOW NOW LOCATED IN FAR EAST CENTRAL TX /NEAR JASPER TX/. THIS LIGHTNING AND SIMILAR INCREASE IN REFLECTIVITIES EXTENDED SSWWD ALONG A DRY LINE/PACIFIC FRONT THROUGH SE TX/UPPER TX COAST /TO THE N-SW OF THE HOUSTON METRO AREA/. TSTMS /MAINLY ELEVATED/ ALSO EXTENDED NEWD OF THE SURFACE LOW INTO NWRN LA. THIS INCREASE IN TSTM DEVELOPMENT IS LIKELY INDICATIVE OF THE ARRIVAL OF STRONG FORCING FOR ASCENT WITHIN THE EXIT REGION OF A 90-100 KT MIDLEVEL JET ACCOMPANYING THE POWERFUL SRN PLAINS SHORTWAVE TROUGH. SUBSEQUENT AND EXPECTED STRENGTHENING OF A SSWLY LLJ WAS EVIDENT OVER SWRN-CENTRAL LA PER 17Z LCH WSR-88D VAD SHOWING 60 KT AT 1 KM AGL. THE STRONG VERTICALLY VEERING WINDS HAVE GREATLY ENHANCED THE EFFECTIVE SRH VALUES UP TO 400-600 M2/S2 TO SUPPORT AN INCREASED TORNADO THREAT...EXPECTED TO SPREAD EWD THIS AFTERNOON INTO THE SRN PART OF THE LOWER MS VALLEY...WITHIN THE WARM SECTOR. LATE MORNING SURFACE ANALYSES SHOWED THE LOW HAS CONTINUED TO DEEPEN AND AT 17Z WAS LOCATED INVOF JASPER TX. A WARM FRONT HAS MOVED STEADILY NWD AND EXTENDED EWD THROUGH CENTRAL LA...SRN MS /N OF KMCB/...TO THE N OF KMOB AND INTO THE WRN FL PANHANDLE. GIVEN THE LOCATION OF THE WARM FRONT...THE SRN EXTENT OF SVR WATCH 693 WILL ALSO HAVE A TORNADO POTENTIAL AS STORMS WILL BE SFC-BASED OR NEAR SFC-BASED. MEANWHILE...THE WARM FRONT HAS MOVED N OF WW 692...THOUGH THE WARM SECTOR ACROSS THIS WW HAS ONLY SLOWLY DESTABILIZED THUS FAR DUE TO THE MIXING RELATED DECREASE IN THE DEWPOINTS. 18Z SLIDELL SPECIAL SOUNDING INDICATED AN INVERSION LOCATED BETWEEN 700-800 MB AND THIS SHOULD CONTINUE TO INHIBIT DEEPER CU DEVELOPMENT UNTIL THE ARRIVAL OF GREATER ASCENT WITH THE EXIT REGION OF THE IMMEDIATELY UPSTREAM MIDLEVEL JET. SOME VEERING OF LOW LEVEL WINDS ACROSS SWRN LA SHOULD ADVECT RICHER MOISTURE INTO SERN LA/SRN MS SUPPORTING STRONGER DESTABILIZATION TO SUPPORT AN ENVIRONMENT FAVORABLE FOR SUSTAINED...DEEP UPDRAFTS. ..PETERS/EDWARDS.. 12/25/2012 Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 Looks like we might have a PDS watch coming... Link to comment Share on other sites More sharing options...
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