andyhb Posted December 25, 2012 Share Posted December 25, 2012 Impressive hook on that thing. Link to comment Share on other sites More sharing options...
Jebman Posted December 25, 2012 Share Posted December 25, 2012 I pray that the people in the Deep South are adequately warned. This weather situation is very serious. Link to comment Share on other sites More sharing options...
WXinCanton Posted December 25, 2012 Share Posted December 25, 2012 things really picking in LA. Hope things fall apart before this system gets to GA. But man crazy supercells in LA at the moment Link to comment Share on other sites More sharing options...
andyhb Posted December 25, 2012 Share Posted December 25, 2012 things really picking in LA. Hope things fall apart before this system gets to GA. But man crazy supercells in LA at the moment These are nowhere near the main show that is expected later on. The H5 jet placement is practically as good as it gets on the RAP for continuing discrete mode. And I see exactly why Cantore placed himself in Hattiesburg, the parameters go absolutely nuts later on there. Link to comment Share on other sites More sharing options...
ksstormhunter Posted December 25, 2012 Share Posted December 25, 2012 SmartCast Analysis for 25 Dec/10Z to 26 Dec 10Z ( Base on my model output only) Full Output (http://smartwxmodel.net/update.htm) First the winter side of the storm system: Currently Targeting McAlester to Little Rock to Hot Springs as the area with the Heaviest Snow potential. Model indicating 6-10” of snow possible in this corridor. McAlester Region: Forecasting snow to begin around 17Z, with periods of heavy snow with snowfall rates of 1.1” possible til 00Z, then snow will slowly decrease. Winds will increase to around 30MPH from 19Z through 10Z. Forecasting a max snow potential of 8.1” til 10Z. Little Rock Region: Looking for rain from 19Z to 02Z, then mixing and changing to all snow by 03Z to 10Z. Looking for periods of heavy snow during this timeframe with snowfall rates of 1.8” per hour possible during this time frame. Forecasting a max snow potential of 10.1” in and around the Little Rock area. In addition, winds will increase to around 40MPH from 01Z to 06Z, which will cause reduced visibilities and blowing snow. Tinker AFB/OKC Region: Forecasting a period of freezing rain and ice pellets through 16Z. Looking at around .1” or less of ice accumulation. Then converting to snow after 16Z, with an additional 2-4” possible across this region. Winds will also increase after 14Z through 00Z, with gusts up to 38MPH possible. Vance AFB Region: Continued snow, with periods of moderate snowfall. Looking at a general 2-3” across this region, with winds increasing to 35MPH from 15Z to 22Z. Dallas Region: Forecasting thunderstorms from 12Z to 20Z, then mixing and changing to snow after 20Z. Looking at 1-2” of accumulation possible from 21Z to 03Z. Winds will also increase to 35 to 42MPH from 20Z to 03Z. Jonesborro and Hot Springs Region: Looking at potential for .3” of ice accumulation followed by 2-4” of snow accumulation possible in the next 24 hours. Severe Wx Potential: Current severe weather zones are Baton Rouge, Lake Charles, and Lafayette regions. Indicating around 73% chance of tornadic storms in the next 24 hours. In addition, hail up to 2.8” and convective wind gusts up to 73 to 75MPH possible. Esler Regional, Mobile, Gulfport, Hattiesburg is another zone with 55 to 60% chance of tornadic storms in their regions. In addition, hail up to 2.5” and wind gusts of up to 60-65MPH possible today. Link to comment Share on other sites More sharing options...
Ed Lizard Posted December 25, 2012 Share Posted December 25, 2012 Short range hi-res looking interesting 15 to 17Z IMBY. My usual RAP/HRRR source giving me issues, but 1 hour precip, and interesting CAPE (MU? SB?) and helicity. Link to comment Share on other sites More sharing options...
Disc Posted December 25, 2012 Share Posted December 25, 2012 MESOSCALE DISCUSSION 2206 NWS STORM PREDICTION CENTER NORMAN OK 0700 AM CST TUE DEC 25 2012 AREAS AFFECTED...SRN LA AND PORTIONS OF SERN TX INCLUDING THE UPPER TX COAST CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 251300Z - 251400Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...AN INCREASE IN SURFACE-BASED TSTMS IS ANTICIPATED THROUGH THE REMAINDER OF THE MORNING HOURS IN THE WARM SECTOR SOUTH OF A WARM FRONT. SUPERCELLS AND BOWING SEGMENTS ARE LIKELY WITH A THREAT FOR TORNADOES...DAMAGING WINDS AND LARGE HAIL. ONE OR MORE TORNADO WATCHES WILL LIKELY BE NEEDED BY 16Z. DISCUSSION...SURFACE LOW PRESSURE WILL CONTINUE TO ORGANIZE OVER S TX THIS MORNING AS A STRONG SHORTWAVE APPROACHES FROM THE WEST. A WARM FRONT EXTENDED FROM NR GYB TO BTR AT 12Z AND WILL LIFT SLOWLY NWD THIS MORNING AS THE SFC LOW MOVES EWD TO N OF HOU BY 16Z. CONTINUED LOW-LEVEL MOISTURE ADVECTION COUPLED WITH COOLING MID-LEVEL TEMPERATURES AS THE SHORTWAVE APPROACHES WILL RESULT IN A MODERATELY UNSTABLE AIR MASS WITH SBCAPE INCREASING TO BETWEEN 1500 AND 2000 J/KG. WIND FIELDS THROUGHOUT THE LOWER/MIDDLE TROPOSPHERE WILL CONTINUE TO STRENGTHEN AND BECOME INCREASINGLY SUPPORTIVE OF SUPERCELL TSTM DEVELOPMENT AS DEEP LAYER SHEAR VALUES EXCEED 60 KTS. INCREASING LOW-LEVEL FLOW WILL RESULT IN 0-1 KM SRH OF 300 M2/S2 OR GREATER THROUGHOUT THE WARM SECTOR AND NEAR THE WARM FRONT...FAVORING LOW-LEVEL ROTATION AND TORNADO DEVELOPMENT. WITH TIME...INITIALLY DISCRETE CELLS MAY MERGE INTO LINE SEGMENTS WITH AN ENHANCED WIND DAMAGE THREAT DUE TO BOWING STRUCTURES/MESOVORTEX DEVELOPMENT. LARGE HAIL IS ALSO LIKELY WITH DISCRETE SUPERCELLS. ONE OR MORE TORNADO WATCHES WILL LIKELY BE REQUIRED PRIOR TO 16Z. Link to comment Share on other sites More sharing options...
NavarreDon Posted December 25, 2012 Share Posted December 25, 2012 MOB overnight: AFDMOB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOBILE AL 421 AM CST TUE DEC 25 2012 WISHING YOU AND YOUR FAMILY A HAPPY AND SAFE CHRISTMAS HOLIDAY FROM ALL OF US AT YOUR NATIONAL WEATHER SERVICE IN MOBILE AL. ...A DANGEROUS SEVERE WEATHER EPISODE IS LIKELY TO EVOLVE THROUGH THE DAY AND TONIGHT...INCLUDING THE POTENTIAL FOR STRONG TORNADOES AND WIDESPREAD DAMAGING WINDS...ACROSS PORTIONS OF THE CENTRAL GULF COAST REGION... .SHORT TERM [TODAY AND TONIGHT]...WATER VAPOR IMAGERY ALONG WITH UPPER LEVEL GEOPOTENTIAL HEIGHT FIELD SHOWS A VIGOROUS STORM SYSTEM/SHARPENING SOUTHERN STREAM TROF PROGRESSING QUICKLY EASTWARD ACROSS TEXAS. THIS IS RESULTING IN INCREASED HIGH LEVEL DIVERGENCE OVER THE CENTRAL GULF COAST/SOUTHEAST. AT THE SURFACE...A STALLED FRONTAL ZONE WAS DRAPED FROM CENTRAL GEORGIA TO THE UPPER TEXAS COAST. TO THE SOUTH...A WARM FRONT WAS DRAPED OFF THE SOUTHEAST LOUISIANA COAST AND INTO THE ALABAMA/WESTERN FLORIDA COASTAL WATERS. SOUTHERN STREAM STORM SYSTEM AMPLIFIES TODAY AS IT HEADS EASTWARD AND BECOMES INCREASINGLY NEGATIVELY TILTED AS IT PIVOTS ACROSS THE LOWER MISSISSIPPI RIVER DELTA. THIS WILL RESULT IN FURTHER HIGH LEVEL DIFFLUENCE AND APPROACH OF STRONG UPPER LEVEL JET ENERGY ASCENT WILL INCREASE COINCIDENT WITH A NORTHWARD MOVING WARM FRONT AND ENHANCED INSTABILITY THROUGH THE COURSE OF THE DAY. STRONG HEIGHT FALLS ALOFT MOVING ACROSS SOUTHERN STATES FRONTAL ZONE SUPPORTS A DEEPENING FRONTAL SURFACE LOW PRESSURE SYSTEM TO TAKE SHAPE OVER EASTERN TEXAS THIS MORNING LIFTING QUICKLY UP INTO CENTRAL MISSISSIPPI BY 6 PM...NE MISSISSIPPI/NW ALABAMA INTO CENTRAL TENNESSEE BETWEEN 12 AM AND DAYBREAK WEDNESDAY. AHEAD OF AND SOUTHEAST OF THE INTENSIFYING LOW...IMPRESSIVE WIND FIELD AND SHEAR PROFILES ALOFT WILL RESULT IN 0-1 KM STORM RELATIVE HELICITY VALUES LIFTING TO 150-200 M2/S2 BY NOON...TRENDING HIGHER INTO THE AFTERNOON/EVENING TO BETWEEN 200 AND 300 M2/S2. THIS SUPPORTS THE LIKELIHOOD OF DEEP AND PERSISTENT ROTATING UPDRAFTS AND TORNADOES IN DISCRETE STORM CLUSTERS. IN FACT...TORNADO PARAMETER GUIDANCE IS ELEVATED OVER THE ENTIRE FORECAST AREA. THE NUMBERS WE SEE SUPPORT POTENTIAL OF LONG TRACK...STRONG TORNADOES. GIVEN THIS...A MODERATE RISK OF SEVERE STORMS IS FORECAST TODAY AND TONIGHT. LARGE HAIL IS ALSO POSSIBLE. FORECASTERS SEE THE STAGE BEING SET FOR A POTENTIAL "DOUBLE WHAMMY". NOT ONLY IS THERE AN ELEVATED TORNADO RISK...BUT THE PASSAGE OF A FAST MOVING...ORGANIZED SQUALL LINE TONIGHT WILL BRING THE LIKELIHOOD OF LOCALIZED DAMAGING WIND GUSTS OF 60+ MPH IN ANY BOWING LINE SEGMENTS. THIS FEATURE...AHEAD OF A STRONG COLD FRONT THAT IS PROGGED TO SURGE EASTWARD BETWEEN 6 PM AND MIDNIGHT. STAY TUNED. ADDITIONAL INFORMATION ON THIS EVENT CAN BE FOUND IN LOCAL HAZARDOUS WEATHER OUTLOOK AND SPECIAL WEATHER STATEMENT PRODUCTS. /10 Link to comment Share on other sites More sharing options...
oldlogin Posted December 25, 2012 Share Posted December 25, 2012 Tornado Watch Link to comment Share on other sites More sharing options...
ksstormhunter Posted December 25, 2012 Share Posted December 25, 2012 SmartCast Analysis for 25 Dec/13Z to 26 Dec 13Z ( Base on my model output only) First the winter side of the storm system: Currently Targeting McAlester to Little Rock to Hot Springs as the area with the Heaviest Snow potential. Model indicating 6-10” of snow possible in this corridor. McAlester Region: Forecasting snow to begin around 17Z, with periods of heavy snow with snowfall rates of 1.1” possible til 01Z, then snow will slowly decrease. Winds will increase to around 30MPH from 19Z through 10Z. Forecasting a max snow potential of 9.5 ” til 10Z. Little Rock Region: Looking for rain til 02Z, then mixing and changing to all snow by 03Z to 13Z. Looking for periods of heavy snow during this timeframe with snowfall rates of 1.8” per hour possible during this time frame. Forecasting a max snow potential of 7” in and around the Little Rock area. In addition, winds will increase to around 40MPH from 01Z to 06Z, which will cause reduced visibilities and blowing snow. Tinker AFB/OKC Region: Forecasting a period of freezing rain and ice pellets through 16Z. Looking at around .1” or less of ice accumulation. Then converting to snow after 16Z, with an additional 2-4” possible across this region. Winds will also increase after 14Z through 00Z, with gusts up to 38MPH possible. Vance AFB Region: Continued snow, with periods of moderate snowfall. Looking at a general 2-3” across this region, with winds increasing to 35MPH from 15Z to 22Z. Dallas Region: Forecasting thunderstorms from 12Z to 20Z, then mixing and changing to snow after 20Z. Looking at 1-2” of accumulation possible from 21Z to 03Z. Winds will also increase to 35 to 42MPH from 20Z to 03Z. Jonesborro Region: Looking at rain/snow and freezing rain through 08Z, then shifting to snow. Looking at .3” of sleet and freezing rain, then 1-2” of snow accumulations. Through 13Z. Severe Wx Potential: Current severe weather zones are Baton Rouge, Lake Charles, and Lafayette regions. Indicating around 84% chance of tornadic storms in the next 24 hours. In addition, hail up to 2.9” and convective wind gusts up to 73 to 75MPH possible. Natchez, MS, Alexandria Esler Regional, Mobile, Gulfport, Hattiesburg is another zone with 55 to 60% chance of tornadic storms in their regions. In addition, hail up to 2.5” and wind gusts of up to 60-65MPH possible today. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 Concern grows this morning for areas just E of Austin to Houston, W Louisiana on E for rapidly developing super cells ahead of the dry line/cold front. Current analysis suggests a dry line is approaching Central Texas as the 5H upper low wraps up just ESE of Lubbock. This upper low continues to slide ESE before turning E then ENE later this morning. The latest HPC ensembles are suggesting a well clustered low developing near San Antonio/Austin and trekking ENE to near Jackson, MS later tonight. A Moderate Risk has been issued from SE Texas, Southern Louisiana, Southern Mississippi and Southern Alabama. The active severe weather should continue on E into the overnight hours of Christmas into the 26th spreading the severe threat further E into Georgia and the Carolinas. Across the cold sector, heavy snow fall is expected from Oklahoma City/Tulsa Arkansas with Blizzard Warnings across W Kentucky/S Illinois/SW Indiana with rapidly deteriorating conditions with a foot+ of snow expected. Currently a mix of freezing rain/sleet/snow is falling in Oklahoma and blowing snow is occurring across the Texas Panhandle as cyclogenesis continues. This is a very dynamic Winter Storm with both severe and winter impacts that are far reaching and societal impacts will be felt across a large portion of the Nation on during a busy Christmas Holiday period. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 From Nesdis: SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 12/25/12 1421Z SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404 LATEST DATA USED: GOES-13: 1345ZVOGT . LOCATION...MISSISSIPPI...LOUISIANA...S MISSOURI...ARKANSAS... LOCATION...TEXAS...OKLAHOMA... . ATTN WFOS...MEG...JAN...LZK...SGF...SHV...TSA...HGX...FWD...OUN... ATTN WFOS...SJT...LUB... ATTN RFCS...LMRFC...MBRFC...ABRFC...WGRFC... . EVENT... PRECIP CONTINUES TO SLOWLY CHANGE OVER TO SNOW FROM NW TO SE ACROSS THE DISCUSSION AREA . SATELLITE ANALYSIS AND TRENDS... MAIN UL VORT CONTINUES ITS TREK ACROSS NRN TX WITH A STRONG UL JET RIDING UNDERNEATH IT... LATEST GOES WV IMAGERY INDICATES EXPANDING/COOLING CLOUD TOPS IN NE TX/NW LA/AR DUE TO THE STRONG UL JET IMPULSE THAT IS CROSSING THROUGH NORTH-CENTRAL TX. THIS IMPULSE APPEARS TO BE MAKING ITS WAY A BIT MORE NORTHWARD AROUND THE UL LOW INTO OK THAT WOULD LIKELY INCREASE THE WINTRY PRECIP IN THAT REGION. GOES-R AIRMASS SOUNDER IMAGERY IS A GOOD INDICATION OF THE STRENGTH OF THE DEEPENING TROF AND UL JET. THERE WAS ALSO ANOTHER IMPULSE RIDING ALONG THE SRN PORTION OF A SECONDARY UL JET THAT HELPED SOME CONVECTION KICK OFF IN SRN LA WITHIN THE PAST HOUR AND SHOULD CONTINUE TO MOVE IN THE NERLY DIRECTION ACROSS MS. . MID-TO-UL WINDS ARE MOSTLY WESTERLY, PER LATEST SATELLITE DERIVED WINDS PRODUCTS. HOWEVER, THERE IS STRONG LL FLOW DIRECTED NWD OUT OF THE GULF... THIS HAS ALLOWED FOR A SUBSTANTIAL DEEPENING OF MOISTURE ACROSS LA/MS/ERN OK/AR OVER THE PAST SEVERAL HOURS AND MOISTURE CONTINUES TO PUSH NWD INTO MO. . SHORT TERM OUTLOOK VALID 1420-1920Z...MEDIUM CONFIDENCE FACTOR IN SHORT TERM OUTLOOK... ATTM, THE BEST CLOUD TOP SIGNATURES ARE MOSTLY ASSOCIATED WITH THE CONVECTION AND HVY RAINFALL OCCURRING ACROSS NE TX/LA/MS... BUT SFC TEMPS ARE DROPPING PRETTY QUICKLY ACROSS OK/NW TX. SO EXPECT A MIXED BAG OF WINTRY PRECIP IN SERN HALF OF OK AND POSSIBLY ALONG THE TX/OK BORDER AS THE UL TROF DEEPENS FURTHER THROUGHOUT THE MORNING HOURS WITH MOD TO HVY SNOW FALLING ACROSS THE WRN PORTIONS OF OK/TX PANHANDLE. THE TRANSITION OVER TO ALL SNOW IN OK/AR SEEMS TO STILL BE AT LEAST A COUPLE HOURS AWAY BUT WILL KEEP AN EYE ON THE SITUATION AS THE MORNING PROGRESSES... Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 832 AM CST TUE DEC 25 2012 THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... HOUSTON COUNTY IN SOUTHEAST TEXAS... * UNTIL 915 AM CST * AT 828 AM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 15 MILES SOUTHWEST OF CROCKETT...AND MOVING NORTHEAST AT 55 MPH. * LOCATIONS IMPACTED INCLUDE... CROCKETT...GRAPELAND...LOVELADY...KENNARD AND LATEXO. EDIT To ADD: Main surface low near Hearne, TX where pressure reading of 998mb was just reported and winds gusting to 43kts Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 842 AM CST TUE DEC 25 2012 THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A * TORNADO WARNING FOR... HOUSTON COUNTY IN SOUTHEAST TEXAS... * UNTIL 930 AM CST * AT 837 AM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 13 MILES SOUTHWEST OF CROCKETT...AND MOVING NORTHEAST AT 50 MPH. * LOCATIONS IMPACTED INCLUDE... CROCKETT...LOVELADY...KENNARD AND LATEXO. PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING ISSUED FOR THE SAME AREA. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 MESOSCALE DISCUSSION 2207 NWS STORM PREDICTION CENTER NORMAN OK 0846 AM CST TUE DEC 25 2012 AREAS AFFECTED...E AND SE TX/WRN AND NRN LA/PART OF WEST CENTRAL-SWRN MS CONCERNING...SEVERE THUNDERSTORM WATCH 691... VALID 251446Z - 251545Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 691 CONTINUES. SUMMARY...A NEW SVR TSTM WATCH WILL BE COORDINATED BY 1450Z WITH AFFECTED WFO/S FROM NE/E TX THROUGH NRN LA TO WEST CENTRAL-SWRN MS...WITH HAIL AND A LOCAL STRONG WIND GUST POSSIBLE. A TORNADO WATCH IS LIKELY TO BE ISSUED FOR MUCH OF SERN TX/UPPER TX COAST AREA INTO SWRN LA TO THE WEST OF WW 692...AS AN INCREASE IN SURFACE-BASED DEVELOPMENT IS EXPECTED AFTER 15Z. DISCUSSION...EARLY MORNING TRENDS IN UPPER AIR DATA/SATELLITE IMAGERY SHOWED A VIGOROUS...DIGGING SHORTWAVE TROUGH MOVING ESEWD ACROSS WRN INTO CENTRAL TX...WITH 140 METER/12 HR 500 MB HEIGHT FALLS AT 12Z AT MAF. STRONG FORCING FOR ASCENT/DPVA WILL SPREAD EWD INTO E TX/LOWER MS VALLEY TODAY. AT 14Z...A WARM FRONT EXTENDED EWD FROM A SURFACE LOW NEAR CLL THROUGH SRN LA /60-80 MILES N OF THE GULF COAST/ AND INTO FAR SERN MS TO ALONG THE COAST OF THE WRN FL PANHANDLE. ...NERN TX/NRN LA/WEST CENTRAL-SWRN MS... REGIONAL RADAR IMAGERY SHOWED ONGOING TSTMS ALONG AND N OF THE WARM FRONT IN MUCH OF THE NERN QUARTER OF TX...WITH THIS ACTIVITY EXPECTED TO DEVELOP/ADVANCE ENEWD INTO NRN LA AND EVENTUALLY WEST CENTRAL-SWRN MS THIS MORNING AND AFTERNOON. STEEP MIDLEVEL LAPSE RATES AOA 8 C/KM PER 12Z TX AND LCH SOUNDINGS AND STRONG EFFECTIVE BULK SHEAR EXCEEDING 60 KT WILL SUPPORT ELEVATED SUPERCELLS WITH HAIL BEING THE PRIMARY THREAT. HOWEVER...A LOCALLY STRONG WIND GUST CANNOT BE RULED OUT...ESPECIALLY WHERE THE BOUNDARY LAYER IS MORE SHALLOW. ...SERN TX TO SWRN LA... STRONG VERTICALLY VEERING WINDS ARE RESULTING IN EFFECTIVE SRH OF 300-400 MS/S2 ALONG AND S OF THE WARM FRONT. THESE VALUES ARE EXPECTED TO INCREASE THIS MORNING/EARLY AFTERNOON AS THE LLJ STRENGTHENS TO AROUND 50 KT AND A 90-100 KT WLY MIDLEVEL JET TRANSLATES EWD INTO SE TX...LA AND SRN MS. THIS COMBINED WITH MODERATE INSTABILITY AND STRONG BULK SHEAR WILL SUPPORT WELL ORGANIZED STORMS/SUPERCELLS. WATER VAPOR IMAGERY INDICATED SOME POTENTIAL SUBSIDENCE IN THE WAKE OF A LEAD IMPULSE IN THE NWRN GULF. HOWEVER...STRONG/DEEP LAYER ASCENT WILL MOVE INTO SERN TX THIS MORNING...PROMOTING SURFACE-BASED TSTM DEVELOPMENT AND THE THREAT FOR TORNADOES. ..PETERS/EDWARDS.. 12/25/2012 ATTN...WFO...JAN...LIX...LCH...SHV...HGX...FWD... Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 Tornado Watch issued for SE TX/SW LA until 22Z Link to comment Share on other sites More sharing options...
southmdwatcher Posted December 25, 2012 Share Posted December 25, 2012 60/60 chances of 2 Tornadoes and 1 EF2+ tornado in this watch box Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 MESOSCALE DISCUSSION 2208 NWS STORM PREDICTION CENTER NORMAN OK 0931 AM CST TUE DEC 25 2012 AREAS AFFECTED...CNTRL/SWRN/S-CNTRL OK...WRN NORTH TX AND PARTS OF N-CNTRL TX CONCERNING...WINTER MIXED PRECIPITATION VALID 251531Z - 252030Z SUMMARY...INITIALLY MIXED PRECIPITATION DEVELOPING OVER...AND 120 STATUTE MILES EITHER SIDE OF THE RED RIVER...WILL INCREASE IN COVERAGE AND INTENSITY DURING THE NEXT HOUR OR TWO. PRECIPITATION WILL TRANSITION TO ALL SNOW BETWEEN 17Z AND 21Z. DISCUSSION...WATER VAPOR LOOPS DEPICTS A WELL-DEFINED CYCLONIC SWIRL MARKING THE CENTER OF A COMPACT MID-LEVEL VORT MAX 55 NNW ABI AS OF 1445Z...WHICH IS TRACKING EWD. PRECIPITATION RATES WILL LIKELY INCREASE DURING THE NEXT HOUR OR TWO...OWING TO STRONG DCVA PRECEDING THE CYCLONE CENTER...COMBINED WITH ISENTROPIC ASCENT ATOP AN OROGRAPHICALLY ENHANCED COLD DOME E OF THE ROCKIES. WITH LOW-LEVEL TRAJECTORIES EMBEDDED WITHIN A WARM CONVEYOR BELT FAVORING THE INFLUX OF RELATIVELY RICHER MOISTURE -- UPSTREAM SOUNDINGS AT 00Z AND 12Z SUGGESTING LOWEST 100-MB MEAN MIXING RATIOS OF 4-7 G/KG -- PRECIPITATION RATES WILL FURTHER INCREASE AS THE FORCING FOR ASCENT INCREASES. THROUGH 17Z...A MIX OF PRECIPITATION WILL OCCUR OWING TO THE EXISTENCE OF WARMER AIR ALOFT -- E.G. ELEVATED WARM NOSE SAMPLED BY THE 12Z NORMAN SOUNDING FEATURING 2-2.8C TEMPERATURES IN THE 900-815-MB LAYER. SLEET...ALONG WITH FREEZING RAIN WITH RATES OF 0.05-0.10 IN PER HOUR...WILL BE POSSIBLE...ESPECIALLY ACROSS S-CNTRL OK IN CLOSER PROXIMITY TO WARMER TEMPERATURES ALOFT. RAIN WILL REMAIN POSSIBLE ACROSS PARTS OF N-CNTRL TX WHERE ABOVE-FREEZING TEMPERATURES EXIST THROUGH A DEEPER LAYER IN THE LOWER TROPOSPHERE. PRECIPITATION WILL MORE QUICKLY TRANSITION TO SNOW WITHIN AN ARC FROM CNTRL OK TO SWRN OK AND WRN NORTH TX...AS DEEPER COLD AIR WRAPS AROUND THE NWRN QUADRANT OF A ERN-TX SFC LOW AND ADIABATIC COOLING OCCURS WITH FORCING FOR ASCENT LEADING THE MID-LEVEL VORT MAX. BETWEEN 17Z AND 21Z...SNOW WILL BECOME WIDESPREAD...WITH THE PRECIPITATION-TYPE TRANSITION ZONE SHIFTING EWD/SEWD ACROSS S-CNTRL OK AND NRN TX. SNOWFALL RATES REACHING 1-1.5 IN/HR WILL OCCUR AS MID-LEVEL ASCENT EXTENDS THROUGH THE DENDRITIC GROWTH ZONE CENTERED AROUND 600 MB. THE HEAVIEST SNOWFALL RATES WILL OCCUR ACROSS SWRN/S-CNTRL OK AND WRN N TX...WHERE CONFLUENCE WITHIN A DEFORMATION ZONE ALOFT SHOULD LOCALLY ENHANCE THE ASCENDING BRANCH OF A FRONTOGENETIC CIRCULATION W/NW OF THE DEEPER CYCLONE. OF NOTE...LOCALIZED BLIZZARD CONDITIONS WILL BE POSSIBLE ACROSS SWRN/S-CNTRL OK AND ADJACENT NRN TX...WHERE FORECAST SOUNDINGS INDICATE 0-1-KM MEAN FLOW INCREASING TO 30-40 KT. OK MESONET OBSERVATIONS ALREADY INDICATE 20-30 MPH SUSTAINED NLY WINDS WITH HIGHER GUSTS ONGOING. WIND SPEEDS SHOULD INCREASE OWING TO THE TIGHTENING SFC PRESSURE GRADIENT AND INCREASING DIFFERENTIAL COLD ADVECTION IN THE LOW LEVELS SUPPORTING DESTABILIZATION JUST ABOVE THE SFC. FREQUENT GUSTS OF 35-40 MPH MAY OCCUR IN SOME LOCATIONS...SUPPORTING WHITEOUT CONDITIONS/NEAR-ZERO VISIBILITIES. ..COHEN.. 12/25/2012 ATTN...WFO...FWD...OUN...SJT... Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 Reports: Tornado- Houston and Trinity County TX Link to comment Share on other sites More sharing options...
NavarreDon Posted December 25, 2012 Share Posted December 25, 2012 Tornado Warning SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 937 AM CST TUE DEC 25 2012 TXC225-373-455-251545- /O.CON.KHGX.TO.W.0039.000000T0000Z-121225T1545Z/ HOUSTON TX-TRINITY TX-POLK TX- 937 AM CST TUE DEC 25 2012 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 945 AM CST FOR EAST CENTRAL HOUSTON...NORTHEASTERN TRINITY AND EXTREME NORTH CENTRAL POLK COUNTIES... AT 933 AM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 11 MILES SOUTHWEST OF WELLS...OR 18 MILES WEST OF LUFKIN...MOVING NORTHEAST AT 50 MPH. THE STORM DOES SHOW SIGNS OF WEAKENING BUT DO NOT LET YOUR GUARD DOWN. THIS TORNADIC THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF EAST CENTRAL HOUSTON...NORTHEASTERN TRINITY AND EXTREME NORTH CENTRAL POLK COUNTIES. PRECAUTIONARY/PREPAREDNESS ACTIONS... TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS. Link to comment Share on other sites More sharing options...
Ed Lizard Posted December 25, 2012 Share Posted December 25, 2012 Wichita Falls- Freezing rain, 28F and winds gusting to 37 mph. Bad Christmas travel conditions. Link to comment Share on other sites More sharing options...
lester Posted December 25, 2012 Share Posted December 25, 2012 15 SE Crockett [Trinity Co, TX] trained spotter reports TORNADO at 09:22 AM CST -- trained spotter reported tornado passed through pasture behind home. HGX: 13 SE Crockett [Houston Co, TX] law enforcement reports TORNADO at 09:22 AM CST -- public report of tornado damage on 287 with a destroyed building. HGX: 9 NW Crockett [Houston Co, TX] emergency mngr reports TORNADO at 09:10 AM CST -- possible tornado reported near houston county lake Link to comment Share on other sites More sharing options...
Ground Scouring 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. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 Concern growing for Beaumont/Lake Charles area. Damage reports with many trees down in Walker County in TX just N of Houston. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 HGX issues Severe Thunderstorm Warning for Harris, Liberty, Montgomery, Polk, San Jacinto Counties. Also numerous trees down in Walker Couty with cable wires across I-45 in Huntsville. The Interstate is closed in both directions. Link to comment Share on other sites More sharing options...
tornadotony Posted December 25, 2012 Share Posted December 25, 2012 Notice the kidney-bean shapes to the cells N of Houston. I have a feeling these will evolve into long-tracked supercells over the next several hours. Link to comment Share on other sites More sharing options...
SquatchinNY Posted December 25, 2012 Share Posted December 25, 2012 Line forming in SE Texas. I think some of them may go tornadic, they have a look to them. Link to comment Share on other sites More sharing options...
SquatchinNY Posted December 25, 2012 Share Posted December 25, 2012 Notice the kidney-bean shapes to the cells N of Houston. I have a feeling these will evolve into long-tracked supercells over the next several hours. LOL, I just posted about that. Yeah, this day will likely be very nasty. Link to comment Share on other sites More sharing options...
Big Jims Videos Posted December 25, 2012 Share Posted December 25, 2012 Notice the kidney-bean shapes to the cells N of Houston. I have a feeling these will evolve into long-tracked supercells over the next several hours. And if my eyes aren't deceiving me each one seems to have some rotation in it according to my radar scope. Quite ominous. Link to comment Share on other sites More sharing options...
Srain Posted December 25, 2012 Share Posted December 25, 2012 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1019 AM CST TUE DEC 25 2012 VALID 251630Z - 261200Z ...THERE IS A MDT RISK OF SVR TSTMS SERN TX INTO THE GULF STATES... ...THERE IS A SLGT RISK OF SVR TSTMS CNTRL TX EWD ACROSS THE GULF COAST STATES TO WRN SC... A SEVERE WEATHER OUTBREAK IS LIKELY TODAY AND TONIGHT FROM SERN TX ACROSS THE GULF COAST STATES. STRONG...LONG-TRACKED TORNADOES AND WIDESPREAD DAMAGING WINDS ARE POSSIBLE. ...SYNOPSIS... A POWERFUL SHORT WAVE TROUGH /EVIDENT ON 1530Z WV IMAGERY OVER W TX/ IS EXPECTED TO QUICKLY PROGRESS EWD AND BECOME NEGATIVELY TILTED OVER THE GULF COAST STATES BEFORE REACHING THE TN VALLEY BY 26/12Z. SIGNIFICANT FORCING FOR ASCENT ATTENDANT TO THE SHORT WAVE WILL PROMOTE VIGOROUS STORM DEVELOPMENT ACROSS CNTRL TX AND THE GULF STATES. MEANWHILE...A DUO OF LEAD SHORT WAVES /OVER LA AND ERN TX AS OF 1530Z/ WILL QUICKLY EJECT NEWD AHEAD OF THE PARENT SYSTEM. IN THE LOW LEVELS...A TX HILL COUNTRY SURFACE LOW IS EXPECTED TO DEEPEN AS IT TRAVERSES ACROSS NRN LA/MS AND INTO MIDDLE TN BY THE END OF THE PERIOD. A COINCIDENT POLEWARD MOVEMENT OF AN EAST-WEST ORIENTED WARM FRONT ACROSS E CNTRL TX...SRN MS/AL AND THE WRN FL PANHANDLE WILL OCCUR...BROADENING THE WARM/MOIST SECTOR OVER THE GULF STATES. MEANWHILE...A SUBTLE N-S SURFACE TROUGH OVER S CNTRL TX WILL BE REINFORCED AS A COLD FRONT SURGES EWD THROUGH THE SABINE RIVER VALLEY TODAY AND THE LOWER MS VALLEY...REACHING WRN GA BY 26/12Z. ...ERN TX EWD ACROSS THE GULF COAST STATES... STRONG/SEVERE ELEVATED THUNDERSTORMS DEVELOPED THIS MORNING ACROSS PORTIONS OF CNTRL TX AND CNTRL/SRN LA IN RESPONSE TO ISENTROPIC ASCENT AND ONGOING WAA. AREA VAD WIND PROFILE DATA SHOWS AN INTENSE LOW LEVEL JET /40-50 KT/ THAT IS FORECAST TO FURTHER INTENSIFY AND BROADEN TODAY COINCIDENT WITH THE APPROACH OF A STRONG UPPER SYSTEM. OBSERVED 12Z SOUNDINGS AT FWD AND CRP REFLECTED STEEP MID-LEVEL LAPSE RATES NEAR 8.2-8.4 C/KM. THESE LAPSE RATES ARE ASSOCIATED WITH AN EML THAT WILL CONTINUE TO PROMOTE THE DEVELOPMENT OF SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL OVER ERN TX/WRN LA THIS MORNING...PARTICULARLY GIVEN STRONG DEEP LAYER SHEAR ATTENDANT TO AN APPROACHING MID-UPPER JET /90-100 KT 500 MB JET AND 120-130 KT 250 MB/. ADDITIONALLY...USING A MODIFIED 12Z FWD SOUNDING...MINIMAL CINH REMAINS OVER TX...SUGGESTING CONVECTION IS BECOMING SURFACE-BASED. 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. AS THE DAY PROGRESSES...FORCED ASCENT ALONG THE ADVANCING COLD FRONT WILL RESULT IN QLCS DEVELOPMENT CONTAINING EMBEDDED FAST-MOVING BOW ECHOES AND POSSIBLE SUPERCELLS/MESO-VORTICES AS IT MOVES EWD ACROSS LA AND THE SRN HALF OF MS. THE NARROW LINE OF SIGNIFICANT STORMS /PRIMARILY CAPABLE OF DMGG WINDS/ WILL QUICKLY PROGRESS THROUGH THE GULF STATES...REACHING WRN GA/THE FL PANHANDLE BY 26/12Z. ..DISPIGNA/COHEN.. 12/25/2012 Link to comment Share on other sites More sharing options...
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