janetjanet998 Posted February 19, 2011 Share Posted February 19, 2011 active pattern coming up next week with seveal systems and an open gulf....SPC's take DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0354 AM CST SAT FEB 19 2011 VALID 221200Z - 271200Z ..DISCUSSION AN ACTIVE...AND APPARENTLY UNPREDICTABLE PATTERN IS SETTING UP BEGINNING AROUND TUE/D4 AS THE MODELS TRY TO HANDLE AN UPPER TROUGH/LOW FORECAST TO MOVE ACROSS BAJA CA AND ANOTHER LARGER-SCALE TROUGH FORECAST TO SINK SWD...OR RETROGRADE...ACROSS THE ERN PACIFIC AND WRN CONUS. AHEAD OF THESE FEATURES...A BROAD WSWLY FLOW REGIME WILL ENCOMPASS THE CNTRL AND ERN CONUS...WITH A STRONG UPPER TROUGH/LOW EXITING NEW ENGLAND ON TUE/D4. BEHIND THIS NE TROUGH...HIGH PRESSURE WILL REMAIN PROVIDING DRY CONDITIONS ACROSS THE ERN STATES WITH GULF MOISTURE SHUNTED OFFSHORE. BY WED/D5...THE TROUGH BEGINS TO AMPLIFY OVER THE WRN STATES...AND A RETURN FLOW BEGINS ACROSS THE GULF OF MEXICO AND INTO TX WITH LOWER TO MID 60S DEWPOINTS ACROSS MUCH TX BY WED AFTERNOON. FROM WED/D5 ONWARD IS WHERE MODELS SUCH AS THE ECMWF AND GFS DIVERGE SUBSTANTIALLY. THE GFS HAS AN UPPER LOW JUST OFF THE NRN BAJA CA COAST BY 00Z THU...WHILE THE ECMWF HAS THE TROUGH AXIS ALONG THE AZ/NM BORDER WITH UPPER HEIGHT FALLS OVERSPREADING THE SRN PLAINS WED NIGHT INTO THU MORNING. IF THE LATTER SOLUTION OCCURS...SEVERE THUNDERSTORMS WOULD BE LIKELY ACROSS PORTIONS OF OK AND TX...AS EARLY AS WED NIGHT...THEN SPREADING EWD ON THU WITH A POTENTIALLY SIGNIFICANT SEVERE WEATHER OUTBREAK FROM THE LOWER MS VALLEY INTO THE OH VALLEY AHEAD OF A DEEPENING LOW. THE GFS...BEING MUCH SLOWER...DEVELOPS A SEVERE THREAT ON LATE THU OVER OK/TX...WITH A MUCH WEAKER UPPER TROUGH AND SURFACE LOW ON THUR AFFECTING THE SRN PLAINS AND LOWER MS VALLEY. WHILE POTENTIAL EXISTS FOR SEVERE WEATHER WED/D5 INTO THU/D6 FROM THE SRN PLAINS INTO THE MS/OH/TN VALLEYS...PREDICTABILITY IS TOO LOW TO INTRODUCE ANY OUTLOOK AREAS. ..JEWELL.. 02/19/2011 Link to comment Share on other sites More sharing options...
tornadotony Posted February 19, 2011 Share Posted February 19, 2011 If the Euro solution were the one that next week were to closely resemble, then there's going to be a major problem from about here down to the TN Valley... Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 20, 2011 Author Share Posted February 20, 2011 for the first time this year an area is highlighted in the 4-8 day outlook DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0347 AM CST SUN FEB 20 2011 VALID 231200Z - 281200Z ..DISCUSSION AN ACTIVE PATTERN WILL PERSIST THROUGH THE PERIOD WITH THE POTENTIAL FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK ON THU/D5. ON WED/D4...MODEL CONSENSUS HAS A BROAD BELT OF SWLY FLOW ALOFT FROM NRN MEXICO ACROSS THE CNTRL AND ERN U.S...AHEAD OF AN UPPER TROUGH AXIS THAT IS FORECAST TO BE IN THE VICINITY OF THE BAJA CA/SRN CA COAST WED MORNING. WELL AHEAD OF THIS FEATURE...LOW LEVEL MOISTURE WILL BEGIN TO STREAM NWD OFF THE GULF OF MEXICO AS A LARGE SURFACE HIGH OVER THE ERN STATES GRADUALLY SHIFTS OFFSHORE. BY THU MORNING...A SURFACE LOW IS FORECAST TO BE SOMEWHERE ACROSS NWRN TX OR CNTRL OK WITH BOUNDARY LAYER DEWPOINTS AS HIGH AS 60F UP TO THE LOW CENTER....AND UP TO A WARM FRONT THAT WILL EXTEND EWD ACROSS NRN OK/AR OR PERHAPS SRN MO. A SURFACE LOW AND POTENT UPPER LEVEL JET STREAK WILL THEN CONTINUE EWD ACROSS THE LOWER MS AND INTO THE TN/OH VALLEYS BY 00Z. UPPER LEVEL COOLING AND A PLUME OF STEEP DEEP LAYER LAPSE RATES WILL OVERSPREAD THE WARM SECTOR...CREATING A VERY UNSTABLE SITUATION. ALTHOUGH THE EXACT GEOMETRY OF THE TROUGH MAY NOT BE WELL HANDLED THIS FAR IN ADVANCE...THE CURRENT MODEL DEPICTION WOULD INDICATE THE POTENTIAL FOR NUMEROUS SUPERCELLS ALONG THE DRYLINE/COLD FRONT...RATHER THAN A MORE LINEAR STORM MODE. IN THIS SCENARIO...A SUBSTANTIAL TORNADO THREAT COULD MATERIALIZE BY AFTERNOON AND EVENING. BY FRI/D6...A SEVERE THREAT OF SOME FORM MAY REMAIN ALONG THE COLD FRONT...AS IT APPROACHES THE ERN SEABOARD...BUT TIMING OF THE FRONT AND PREDICTABILITY BECOME TOO LOW FOR ANY ADDITIONAL SEVERE AREAS. Link to comment Share on other sites More sharing options...
Indystorm Posted February 20, 2011 Share Posted February 20, 2011 Ya, looks like low level moisture will not be a problem with this system and this may be our first moderate of the season for the outlined region. Temps are certainly warm enough and cells wil start spinning with progged shear and helicity. Link to comment Share on other sites More sharing options...
tornadotony Posted February 20, 2011 Share Posted February 20, 2011 Without a major trough axis to force things linear, with sfc pressures that low, with that much shear, instability, and moisture likely to be in place...it's too far out to say for certain how bad this is going to end up being, but the potential ceiling for this is certainly for it to end up being a blockbuster tornado outbreak. Of course, those take too many perfect mesoscale variables to occur, but this setup could be very very interesting. In fact, it reminds me of the setup for the Tri-State tornado, with the path of that sfc low, with the area under threat (remember there were violent tornadoes in the south later that afternoon), and with the movement of the tornadoes, it can be inferred that at least the direction of the flow aloft in the outbreak area was similar. Link to comment Share on other sites More sharing options...
hoosierwx Posted February 20, 2011 Share Posted February 20, 2011 Without a major trough axis to force things linear, with sfc pressures that low, with that much shear, instability, and moisture likely to be in place...it's too far out to say for certain how bad this is going to end up being, but the potential ceiling for this is certainly for it to end up being a blockbuster tornado outbreak. Of course, those take too many perfect mesoscale variables to occur, but this setup could be very very interesting. In fact, it reminds me of the setup for the Tri-State tornado, with the path of that sfc low, with the area under threat (remember there were violent tornadoes in the south later that afternoon), and with the movement of the tornadoes, it can be inferred that at least the direction of the flow aloft in the outbreak area was similar. Yikes. I wonder if we do end up with a moderate or high risk what the earliest that has occured that far north? Link to comment Share on other sites More sharing options...
Hoosier Posted February 20, 2011 Share Posted February 20, 2011 Yikes. I wonder if we do end up with a moderate or high risk what the earliest that has occured that far north? There was a high risk that went into northern Illinois on 3/12/06. Link to comment Share on other sites More sharing options...
Indystorm Posted February 20, 2011 Share Posted February 20, 2011 There was a high risk that went into northern Illinois on 3/12/06. That was such a thrilling event to follow throughout the day as those supercells came ne from Missouri. Link to comment Share on other sites More sharing options...
patrick7032 Posted February 20, 2011 Share Posted February 20, 2011 There was a high risk that went into northern Illinois on 3/12/06. If this pans out if if anyone wants a ride I will probably go chasing Thursday since this would be my last chance to see a tornado for a while before I report to Cold Bay in a few weeks. Link to comment Share on other sites More sharing options...
Indystorm Posted February 20, 2011 Share Posted February 20, 2011 If this pans out if if anyone wants a ride I will probably go chasing Thursday since this would be my last chance to see a tornado for a while before I report to Cold Bay in a few weeks. Hope the event materializes well for you before your move to Alaska and you have a good chase! Link to comment Share on other sites More sharing options...
patrick7032 Posted February 20, 2011 Share Posted February 20, 2011 Hope the event materializes well for you before your move to Alaska and you have a good chase! Thanks....I have until March 9th to get one in as I have to have my Liberty in Seattle on the 10th to be loaded onto the boat. Link to comment Share on other sites More sharing options...
SEMIweather Posted February 20, 2011 Share Posted February 20, 2011 If this pans out if if anyone wants a ride I will probably go chasing Thursday since this would be my last chance to see a tornado for a while before I report to Cold Bay in a few weeks. Come down to Oklahoma... Link to comment Share on other sites More sharing options...
brettjrob Posted February 20, 2011 Share Posted February 20, 2011 There was a high risk that went into northern Illinois on 3/12/06. 2008-01-07 probably could've at least come close to verifying MDT for the same region, too. Bottom line: it's definitely not unheard of to see significant tornado events that far north in the late winter east of the Plains states. Link to comment Share on other sites More sharing options...
David Reimer Posted February 20, 2011 Share Posted February 20, 2011 Definitely an interesting event shaping up for Thursday. The moment I looked at data this morning I had revolutions about Super Tuesday 2008 and how significant that event ended up being. For some reason, that event came up a lot today when I was looking over data. Its rather difficult to pin down a specific area because the models keep adjusting the timing by a few hours, which have significant implications on where initiation ends up being. The GFS has had cells firing up just east of Dallas, but if this ends up slowing down at all the D/FW metroplex could be in big trouble if we end up getting backed surface and low level winds. East Texas, Louisiana, Arkansas are in serious trouble with this event, and if we have a surprise like December 31 where moisture and 3 KM CAPE extended all the way up to the surface low, then this has the potential to be a HUGE severe weather outbreak. I've posted a slightly less doomsday, more detailed discussion over on my website. Feel free to hit it up at www.texasstormchasers.com Link to comment Share on other sites More sharing options...
CUmet Posted February 20, 2011 Share Posted February 20, 2011 Back trajectories suggest moisture will absolutely not be a problem for this event, taken from the HYPSLIT trajectory model (a great resource, btw). The feed from the Caribbean compares favorably with other winter/early-spring significant severe events in the recent past, going through the archived trajectories. Link to comment Share on other sites More sharing options...
Indystorm Posted February 21, 2011 Share Posted February 21, 2011 From tonight's 84 hr. NAM there's a nice 300 mb 100 knot jet over PAH area. Thurs. am. I think you may be very much in the game with this one, particularly if intensity ramps up and we get a somewhat northward trend and 500 mb starts to go negative tilt. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 21, 2011 Share Posted February 21, 2011 From tonight's 84 hr. NAM there's a nice 300 mb 100 knot jet over PAH area. Thurs. am. I think you may be very much in the game with this one, particularly if intensity ramps up and we get a somewhat northward trend and 500 mb starts to go negative tilt. PAH would very much be in the game extrapolating the 0z NAM, this run came in a bit further north and a tad faster than the previous GFS run. Link to comment Share on other sites More sharing options...
blackjack123 Posted February 21, 2011 Share Posted February 21, 2011 Could be a very dangerous day? I wonder if there will be an EF4 or EF5 tornado in this potentially large tornado outbreak. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 21, 2011 Share Posted February 21, 2011 Could be a very dangerous day? I wonder if there will be an EF4 or EF5 tornado in this potentially large tornado outbreak. too early to say that.. Link to comment Share on other sites More sharing options...
Stebo Posted February 21, 2011 Share Posted February 21, 2011 Could be a very dangerous day? I wonder if there will be an EF4 or EF5 tornado in this potentially large tornado outbreak. Might be best to wait until we get some tornadoes before mentioning strength. As for the event this could be the start of a very active pattern, as there are other storms down the pipe still to come in the next couple of weeks. Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 21, 2011 Share Posted February 21, 2011 Today's Day 4 outlook area very similar to yesterday's Day 5 outlook. It would appear confidence is growing. DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0353 AM CST MON FEB 21 2011 VALID 241200Z - 011200Z ...DISCUSSION... AN OUTBREAK OF SEVERE THUNDERSTORMS APPEARS LIKELY ON THU/D4 FROM ERN OK/NERN TX EWD ACROSS MUCH OF AR...SRN MO...NRN MS...CNTRL AND WRN KY AND TN...AND POSSIBLY CONTINUING INTO FRI/D5 ACROSS PORTIONS OF THE MID ATLANTIC STATES. MODELS ARE IN GOOD AGREEMENT IN DEPICTING A POTENT UPPER SHORTWAVE TROUGH MOVING EWD ACROSS THE SRN PLAINS DURING THE DAY THU WITH A SURFACE LOW DEEPENING FROM ROUGHLY OK AT 12Z TO MO/AR BY 00Z. AHEAD OF THE DEEPENING LOW...A RELATIVELY WIDE MOIST/WARM SECTOR WILL BE IN PLACE WITH BOUNDARY LAYER DEWPOINTS IN THE 60S F. STRONG FORCING WITH THE UPPER TROUGH...COOLING MID LEVEL TEMPERATURES AND THE PRESENCE OF VERY STRONG WIND PROFILES SUGGEST SIGNIFICANT SEVERE WEATHER WILL BE POSSIBLE...INCLUDING TORNADOES AND VERY STRONG WINDS IN ADDITION TO HAIL. THE GREATEST THREAT AREA ON THU WILL LIKELY BE NEAR AND JUST S OF THE SURFACE LOW TRACK DURING THE LATE AFTERNOON AND EVENING HOURS. LATEST ITERATION OF NUMERICAL GUIDANCE SUGGESTS THAT THIS WOULD INCLUDE MUCH OF AR...SRN MO...FAR NRN MS...AND MUCH OF WRN KY AND TN. SOME SEVERE THREAT WILL LIKELY PERSIST OVERNIGHT AND CONTINUE INTO FRI/D5...ALTHOUGH INSTABILITY AND MOISTURE WILL BE LESS. AS SUCH...THE EXPECTED SEVERE THREAT FRI WILL LIKELY BE COMPRISED OF DAMAGING WIND GUSTS ASSOCIATED WITH AN INTENSE COLD FRONT AND A STRONGLY FORCED LINE OF STORMS...FROM THE DELMARVA SWD ACROSS VA. THESE STORMS WOULD LIKELY HAVE LITTLE INSTABILITY TO WORK WITH...AND WOULD BE RELATIVELY LOW TOPPED...BUT A STRONG SURFACE PRESSURE FALL/RISE COUPLET WOULD ENHANCE WIND POTENTIAL WITH THE LINE. AFTER THE D4 TO D5 TIME FRAME...MODEL SOLUTIONS DIVERGE RAPIDLY. ..JEWELL.. 02/21/2011 CLICK TO GET WUUS48 PTSD48 PRODUCT Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 21, 2011 Share Posted February 21, 2011 Instability would seem to be the limiting factor for severe late Thursday afternoon per GFS. Instability low, but impressive wind fields forecast... Link to comment Share on other sites More sharing options...
David Reimer Posted February 21, 2011 Share Posted February 21, 2011 Could be a very dangerous day? I wonder if there will be an EF4 or EF5 tornado in this potentially large tornado outbreak. Link to comment Share on other sites More sharing options...
blackjack123 Posted February 21, 2011 Share Posted February 21, 2011 I said it could. I did not say it would. Link to comment Share on other sites More sharing options...
blackjack123 Posted February 21, 2011 Share Posted February 21, 2011 I dont know much but I am just happy to see a delineated forecast and possible mentioning of a significant tornado outbreak. Link to comment Share on other sites More sharing options...
David Reimer Posted February 21, 2011 Share Posted February 21, 2011 I said it could. I did not say it would. Without providing some proof to back those types of statements up they are nothing more then weenie speculation, and its better to refrain from posting in those cases. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 21, 2011 Share Posted February 21, 2011 Both the 0z GFS and the 12z NAM are blowing up precip early in the afternoon in the warm sector, which is preventing further sfc heating a few more hours and only getting around 500 j/g of CAPE. The LL shear in the warm sector during the afteroon thursday is through the roof. The sfc winds are pretty veered just east of the dryline at 18z and you have to go further east in the warm sector or near the warm front to get better sfc flow but only continue to veer more as you get into the late afternoon evening hours. Link to comment Share on other sites More sharing options...
on_wx Posted February 21, 2011 Share Posted February 21, 2011 The 09z SREF isn't looking that impressive for hours 81 and 87. No tornado spread and 1,000 jkg CAPE is at 10% for 21z-00z. Though, supercells can fire at 500 j/kg this time of year, can't they? Link to comment Share on other sites More sharing options...
Hoosier Posted February 21, 2011 Share Posted February 21, 2011 The 09z SREF isn't looking that impressive for hours 81 and 87. No tornado spread and 1,000 jkg CAPE is at 10% for 21z-00z. Though, supercells can fire at 500 j/kg this time of year, can't they? With good shear, 500 J/kg can be enough especially if it's focused in the low levels. I suspect this will be another case where the model surface temps in the warm sector will be underdone, particularly if the stronger solutions verify, so might want to keep that in mind. Link to comment Share on other sites More sharing options...
MoeWx Posted February 21, 2011 Share Posted February 21, 2011 The 09z SREF isn't looking that impressive for hours 81 and 87. No tornado spread and 1,000 jkg CAPE is at 10% for 21z-00z. Though, supercells can fire at 500 j/kg this time of year, can't they? Correct. This time of year there does not need to be a robust amount of instability, the wind profiles look especially impressive though. Not to mention the models have struggled with low level warm air advection in recent weeks... actually they failed yesterday. Definately one we want to keep a very close eye on, especially of the clearing (Sunlight...) that has occurred with the aforementioned previous advection cases. Link to comment Share on other sites More sharing options...
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