baroclinic_instability Posted March 13, 2011 Share Posted March 13, 2011 Wow--the 12Z EUro op looks much different day 6--a bit of a surprise since it was in lockstep with the GFS through day 5. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted March 13, 2011 Share Posted March 13, 2011 I rarely ever bust out the CMC since it is such a bad global model--but I am doing it for illustrative purposes here. Euro op has a similar breakdown of the western trough into a low amplitude shortwave. Euro had suggested this type of a pattern breakdown a couple days ago so I guess it shouldn't be a surprise. Well within the envelope of solutions day 5+. http://www.meteo.psu...2z/cmcloop.html Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 13, 2011 Share Posted March 13, 2011 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0328 AM CDT SUN MAR 13 2011 VALID 161200Z - 211200Z ...DISCUSSION... ECMWF AND GFS ARE IN REASONABLE AGREEMENT REGARDING LARGE SCALE FEATURES INTO THE LATTER PART OF THIS WEEK. OF PARTICULAR NOTE WILL BE THE GRADUAL STRENGTHENING SWLY FLOW ALOFT ACROSS THE SWRN U.S. INTO THE NRN PLAINS WHICH SHOULD ENCOURAGE SEVERAL BOUTS OF LEE CYCLOGENESIS AND MORE FAVORABLE TRAJECTORIES FOR RETURN MOISTURE INTO THE SRN/CNTRL PLAINS. GIVEN THAT RICHER MOISTURE LIKELY WILL HOLD OFF MOVING INLAND UNTIL THE VERY END OF THE MEDIUM RANGE WILL NOT INTRODUCE A RISK FOR ORGANIZED SEVERE THUNDERSTORMS AT THIS TIME. ALTHOUGH...IF SUBSEQUENT MODEL RUNS SUGGEST A WRN U.S. TROUGH WILL EVOLVE BY LATE WEEK AN INCREASING RISK FOR STRONG/SVR TSTMS MAY DEVELOP BY NEXT WEEKEND. ..DARROW.. 03/13/2011 Link to comment Share on other sites More sharing options...
WxMidwest Posted March 13, 2011 Share Posted March 13, 2011 I don't think your nuts at all, using analogs of similar setups 6-10 and 8-14 days out, the threat is definitely there... 6-10 day Tornado Analog Composite Maps 8-14 day Tornado Analog Composite Maps Link to comment Share on other sites More sharing options...
Chicago Storm Posted March 13, 2011 Share Posted March 13, 2011 I don't think your nuts at all, using analogs of similar setups 6-10 and 8-14 days out, the threat is definitely there... 6-10 day Tornado Analog Composite Maps 8-14 day Tornado Analog Composite Maps The 8-14 day CPC analog actually features our first severe wx/chase case (4-9-99)... http://www.americanwx.com/bb/index.php/topic/14883-virtual-severe-weather-forecast-and-chase-contest/page__view__findpost__p__540494 Link to comment Share on other sites More sharing options...
WxMidwest Posted March 13, 2011 Share Posted March 13, 2011 The 8-14 day CPC analog actually features our first severe wx/chase case (4-9-99)... http://www.americanw...post__p__540494 Yeah, stebo mentioned it in chat last night... The Juice could be loose.. I'm gonna try to make these maps every 2-3 days... Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 13, 2011 Share Posted March 13, 2011 Brett's reference to the Tulia, TX tornado day (4/21/07) Link to comment Share on other sites More sharing options...
blackjack123 Posted March 13, 2011 Share Posted March 13, 2011 This system is just the bellwether for what's to come after. I know. I am so ready for the main shows. Link to comment Share on other sites More sharing options...
brettjrob Posted March 13, 2011 Share Posted March 13, 2011 Sunday afternoon AFD's from AMA and LUB, respectively: ATTENTION THEN TURNS TO THE UPCOMING WEEKEND AS LOW LEVEL MOISTURE RETURNS AND CLOSED UPPER LOW OVER CA TRACKS SLOWLY EAST AND NORTHEAST ACROSS THE INTERMOUNTAIN REGION SATURDAY AND SUNDAY. GOOD UPPER LEVEL SUPPORT FROM LEADING SHORTWAVE ENERGY APPROACHING THE PANHANDLES FROM THE ROCKIES AND FOUR CORNERS REGION ALONG WITH AN EXPECTED DRYLINE SETTING UP ACROSS EASTERN CO AND EASTERN NM SHOULD SET THE STAGE FOR INCREASING POSSIBILITY FOR CONVECTION BY LATE SATURDAY AND SATURDAY NIGHT. LATER SHIFTS SHOULD WATCH THIS CLOSELY AS THE POSSIBILITY FOR SEVERE WEATHER EXISTS AND CONFIDENCE LEVEL IS INCREASING. SOLUTIONS CONTINUE TO AGREE TOWARD INCREASINGLY SOUTHWESTERLY FLOW ALOFT OVER THE SOUTHERN PLAINS/ROCKIES THROUGH THE REMAINDER OF THE WORK WEEK AS A LARGE SCALE UA TROUGH EVOLVES OVER THE WESTERN U.S. THIS PATTERNS APPEARS FAVORABLE FOR DEEPENING LEE TROUGHINESS AN SUSTAINED MOISTURE RETURN NORTHWESTWARD TOWARD THE HIGH PLAINS... LIKELY RESULTING IN A SLOSHING DRYLINE. MODELS DO NOT APPEAR TO BE IN GOOD AGREEMENT IN RESOLVING DAY-TO-DAY RAIN CHANCES WITHIN THIS REGIME...AND THE PATTERN FAVORS AN EML OVERSPREADING THE SOUTHERN PLAINS DRYLINE. HOWEVER SOME MODELS GENERATE INTERMITTENT/LIGHT CONVECTIVE QPF IN VICINITY THE DRYLINE...BUT MANY DIFFERENCES REMAIN IN HANDLING BOTH SAID FEATURE AND WEAK SOUTHWARD FRONTAL PUSHES THROUGH THE PLAINS...SO CONFIDENCE IS LOW. ATTM...WILL MAINTAIN AND EXPAND MINIMAL SLIGHT CHANCE /15-20 PERCENT/ POPS WEDNESDAY AND WEDNESDAY NIGHT...CONSISTENT WITH THE ONSET OF WARM/ MOIST ADVECTION AND ANY POTENTIAL WEAK UA FEATURE TRANSLATING EASTWARD TOWARD THE DRYLINE. AGAIN...CONFIDENCE REMAINS LOW WRT PIN POINTING SPECIFIC DAYS... BUT THE OVERALL PATTERN WOULD SUPPORT THE ONSET OF ACTIVE WEATHER SOMETIME NEXT WEEKEND OR EARLY NEXT WEEK AS THE WESTERN U.S. TROUGH EVENTUALLY EJECTS. WHILE THE FOCUS MAY TURN TOWARDS DRYLINE RELATED CONVECTION DURING THAT TIMEFRAME...PERIODS OF CRITICAL FIRE WEATHER MAY ADDITIONALLY MATERIALIZE WEST OF THE DRYLINE. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted March 13, 2011 Share Posted March 13, 2011 18Z GFS op looks more like the other globals now with a slow breakdown and de-amplification of the trough into the plains. Still a long ways to go--but better than a slow and elongated positive tilt trough that the GFS was suggesting in earlier runs. I was actually thinking this may slow down--but that may not be the case if the guidance continues with a strong backside low amplitude jet effectively kicking the trough out into the plains. Link to comment Share on other sites More sharing options...
brettjrob Posted March 14, 2011 Share Posted March 14, 2011 18Z GFS op looks more like the other globals now with a slow breakdown and de-amplification of the trough into the plains. Still a long ways to go--but better than a slow and elongated positive tilt trough that the GFS was suggesting in earlier runs. I was actually thinking this may slow down--but that may not be the case if the guidance continues with a strong backside low amplitude jet effectively kicking the trough out into the plains. Somehow this doesn't surprise me. It seems like it's been a long while since a deep trough plowed into the Desert SW; hence the drought conditions over OK/TX. It can be tough to get that to happen in Nina years like this. While there's still hope for an interesting severe weather event even if this trough comes out de-amplifying, it will be kind of disappointing in the sense that getting a deep wrn CONUS trough might have signaled hope for the reversal of drought conditions in the S Plains (and associated correlations with inactive Plains severe wx seasons). Link to comment Share on other sites More sharing options...
theduke85 Posted March 14, 2011 Share Posted March 14, 2011 All i have to say is that were going to see several severe threats later in the week into next weekend, somewhere may see a major outbreak but we don't know where, my bet right now is the Ohio Valley into Appalachians or Midwest Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 14, 2011 Share Posted March 14, 2011 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 14, 2011 Share Posted March 14, 2011 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0316 AM CDT MON MAR 14 2011 VALID 171200Z - 221200Z ...DISCUSSION... VARIOUS FORECAST MODELS APPEAR TO BE IN REASONABLE AGREEMENT WITH THE EVOLUTION OF THE LARGE SCALE PATTERN OVER THE NEXT WEEK OR SO. THE PATTERN WILL FEATURE A TENDENCY FOR WRN U.S. TROUGHS WITH SWLY FLOW ACROSS THE PLAINS...AND FOR A MEAN UPPER RIDGE TO EXIST OVER THE ERN STATES. THIS WILL FAVOR LOW LEVEL FLOW OFF THE GULF OF MEXICO FOR NWD MOISTURE RETURN BENEATH RELATIVELY STRONG SWLY FLOW ALOFT. HOWEVER...THERE ALSO APPEARS TO BE A TENDENCY FOR A SURFACE HIGH TO EXIST OVER OR JUST OFF THE SERN U.S. COAST. OVERALL TRAJECTORIES FEEDING MOISTURE NWD INTO THE PLAINS STATES ARE ULTIMATELY ORIGINATING OUT OF THIS HIGH...AND MODELS ARE LIMITING BOUNDARY LAYER DEWPOINTS TO THE 50S AND LOWER 60S. WHILE THIS MAY STILL FAVOR SEVERE WEATHER POTENTIAL...TIMING OF THE UPPER WAVES ALSO APPEAR TO BE IN QUESTION...WITH PREDICTABILITY TOO LOW FOR ANY AREAS. HOWEVER...THE BEST CONDITIONAL THREAT FOR SEVERE STORMS AT THIS TIME APPEARS TO BE IN THE SAT/D6 THROUGH MON/D8 TIME FRAME WHEN THE WRN TROUGH IS FORECAST TO EJECT EWD ACROSS THE PLAINS. ..JEWELL.. 03/14/2011 Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted March 14, 2011 Share Posted March 14, 2011 The week of the 20th still looks prime for plenty of severe weather episodes Link to comment Share on other sites More sharing options...
brettjrob Posted March 14, 2011 Share Posted March 14, 2011 HOWEVER...THERE ALSO APPEARS TO BE A TENDENCY FOR A SURFACE HIGH TO EXIST OVER OR JUST OFF THE SERN U.S. COAST. OVERALL TRAJECTORIES FEEDING MOISTURE NWD INTO THE PLAINS STATES ARE ULTIMATELY ORIGINATING OUT OF THIS HIGH...AND MODELS ARE LIMITING BOUNDARY LAYER DEWPOINTS TO THE 50S AND LOWER 60S. I've got a whole laundry list of things that annoy the piss out of me when it comes to chasing and severe wx, but I don't think anything tops watching a perfectly good trough go to waste because of another ern US trough too close downstream. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 14, 2011 Share Posted March 14, 2011 I've got a whole laundry list of things that annoy the piss out of me when it comes to chasing and severe wx, but I don't think anything tops watching a perfectly good trough go to waste because of another ern US trough too close downstream. Were not out of it yet, hopefully we can get this setup to change for the better. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 14, 2011 Share Posted March 14, 2011 18z NAM spitting out a decent amount of instability thursday night and into friday morning from northwest MO to northern IL. showing 60 dew points getting up to DVN. Link to comment Share on other sites More sharing options...
Jim Martin Posted March 14, 2011 Author Share Posted March 14, 2011 Look at this potential dryline setup for next Monday. Map is valid at 2 pm edt/1pm cdt next Monday. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted March 15, 2011 Share Posted March 15, 2011 Look at this potential dryline setup for next Monday. Map is valid at 2 pm edt/1pm cdt next Monday. Saturday threat is pretty much a wash now with meager moisture return and the aforementioned cruddy GOM trajectories--Sunday and Monday look potentially better once the trough ejects. Still a lot of uncertainty regarding how the trough is configured as it ejects into the plains though. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 15, 2011 Share Posted March 15, 2011 pretty much have lost all hope for anything saturday...and dont know if were going to drive all the way down for one chase day on sunday. DDC discussion on sunday.. THE NEXT SHORTWAVE TROUGH IS ADVERTISED BY THE ECMWF/GEM TO APPROACH OUR FORECAST AREA LATE SUNDAY. BY THIS TIME, DEWPOINTS BETWEEN 55 AND 62F (13 AND 17C) SHOULD BE IN PLACE IN THE EASTERN PART OF OUR FORECAST AREA AHEAD OF THE DRYLINE. CLIMATOLOGICALLY, DEWPOINTS AS HIGH AS THIS ARE HARD TO GET IN MARCH. HOWEVER, SINCE STRONG FRONTAL INTRUSIONS ARE NOT EXPECTED INTO THE GULF OF MEXICO BETWEEN NOW AND SUNDAY, AND SINCE THE GULF IS ALREADY CLOSE TO EQUILIBRIUM WITH DEWPOINTS IN THE HIGH 60S, A VERY ROBUST RETURN OF LOW-LEVEL MOISTURE CAN BE EXPECTED. 500MB AND 300MB TEMPERATURES ARE PROGGED TO BE FAIRLY COLD (-17C AND -45C RESPECTIVELY) SO THAT MODERATE SURFACE BASED CAPE VALUES ARE POSSIBLE WITH DAYTIME HEATING JUST AHEAD OF THE DRYLINE. VERTICAL WIND SHEAR PROFILES ARE ALSO EXPECTED TO BE ROBUST WITH 60KT WEST-SOUTHWEST WINDS AT 500MB AND SURFACE WINDS FROM THE SOUTH TO EVEN SOUTH-SOUTHEAST. HOWEVER, GIVEN THE STRONG WEST-SOUTHWESTERLY FLOW FROM 700-500MB, ANY STORMS THAT DEVELOP ALONG THE DRYLINE WILL MOVE FAIRLY QUICKLY INTO CENTRAL AND SOUTH-CENTRAL KANSAS. THEREFORE, THE WESTERN EDGE OF THE SEVERE STORM THREAT IS EAST OF A LINE FROM HAYS TO DODGE CITY TO ASHLAND, WITH THE HIGHER CHANCES IN PLACES LIKE PRATT AND STAFFORD. Link to comment Share on other sites More sharing options...
Jim Martin Posted March 15, 2011 Author Share Posted March 15, 2011 Nice dryline setting up for KS/OK/TX for Sunday evening at 8 pm edt/7 pm cdt. Link to comment Share on other sites More sharing options...
brettjrob Posted March 15, 2011 Share Posted March 15, 2011 12z GFS pretty much puts the entire thing in the trashbin. Trough hangs back on the coast all weekend, then just shears out to the NE on Monday. Meanwhile, incessant troughing over E Canada and New England completely ruins any chance of true quality moisture return. Bring on May... or maybe just the next El Nino year. EDIT: OK, now I realize I was looking at the wrong hours (12z instead of 00z), lol. It still looks fairly grim, but Saturday might have a shot way out west around Dalhart or Boise City. H85 winds on Sun/Mon don't look terribly impressive as they did on previous runs, but that could change. In any case, the poor low-level trajectories coming into the Gulf from the NE will certainly place a ceiling on the potential. This is readily apparent by the fact that good juice (Td >65 F) is sitting just off the Gulf Coast by tomorrow, yet despite southerly flow almost the entire week, never makes it to I-20. Link to comment Share on other sites More sharing options...
KokomoWX Posted March 15, 2011 Share Posted March 15, 2011 Not quite the dates but Larry Cosgrove had this to just after lunchtime... Larry Cosgrove The big threat for a severe weather outbreak in the March 22 - 23 time frame is still on. Good agreement between the operational and ensemble formats of the GFS equation in deepening a low that ejects from Colorado into northern New England. Excellent moisture fetch around mTw ridge in Florida. Cold flush pulled into storm spells big problems for entire Ohio Valley on March 23; thunderstorms could train while being big hail developers IL/IN/KY/WV/OH/W PA. Link to comment Share on other sites More sharing options...
brettjrob Posted March 15, 2011 Share Posted March 15, 2011 12z GFS is a slow outlier within the GEFS for Sunday: http://www.nco.ncep....fs_500_132m.gif http://www.nco.ncep....fs_50c_132m.gif And by Monday evening, the discrepancy between the op and virtually all the other ensemble members is ridiculous: http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_500_156m.gif http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gefs/12/images/gefs_50c_156m.gif However, the other global operational models like the slower idea, so it's still anyone's guess. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 15, 2011 Share Posted March 15, 2011 FWIW..the 12z Euro has a wider area of decent instability for sunday from NE down through KS to western OK (1000-1500 j/kg) Link to comment Share on other sites More sharing options...
baroclinic_instability Posted March 15, 2011 Share Posted March 15, 2011 12z GFS is a slow outlier within the GEFS for Sunday: http://www.nco.ncep....fs_500_132m.gif http://www.nco.ncep....fs_50c_132m.gif And by Monday evening, the discrepancy between the op and virtually all the other ensemble members is ridiculous: http://www.nco.ncep....fs_500_156m.gif http://www.nco.ncep....fs_50c_156m.gif However, the other global operational models like the slower idea, so it's still anyone's guess. FWIW..the 12z Euro has a wider area of decent instability for sunday from NE down through KS to western OK (1000-1500 j/kg) Yeah the Euro throws a bone regarding the second trough ejecting into the plains Mon-Tues, but for now, not terribly excited since plenty of spread exists regarding the first less than impressive looking ejecting wave. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 16, 2011 Share Posted March 16, 2011 Monday is starting to look like the best day (ofcourse since I can't chase). 0z GFS showing > 60 dew points making it up to the KS/NE border east of the dryline with a nice pocket of instability, nothing major (around 1500 j/kg) but better than what its showing for sunday. Also getting better/stronger shear. 850's stronger on monday evening and more of a southerly component to them in north central KS. Still days away so things will most likely change. Link to comment Share on other sites More sharing options...
Ed Lizard Posted March 16, 2011 Share Posted March 16, 2011 30% implied certainty, if I'm not mistaken. DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0330 AM CDT WED MAR 16 2011 VALID 191200Z - 241200Z ...DISCUSSION... BOTH THE ECMWF AND GFS ARE IN FAIRLY GOOD AGREEMENT REGARDING THE LARGE SCALE EVOLUTION OF A PRONOUNCED WRN U.S. TROUGH INTO THE DAY4-5 TIME FRAME. IT APPEARS NRN/CNTRL PLAINS RIDGING WILL FLATTEN CONSIDERABLY BY SATURDAY AS BROAD SWLY FLOW AT MID LEVELS OVERSPREADS THE HIGH PLAINS INDUCING LEE TROUGHING ACROSS ERN CO...SWD ALONG THE NM/TX BORDER. ALTHOUGH LATEST MODEL GUIDANCE MAINTAINS ONLY MODEST INSTABILITY ACROSS THE WARM SECTOR IT WOULD SEEM THAT HEATING ACROSS THE HIGH PLAINS SHOULD ENCOURAGE AT LEAST ISOLATED TSTM DEVELOPMENT...SOME OF IT SUPERCELLULAR...DURING THE LATE AFTERNOON/EVENING HOURS. MORE SUBSTANTIAL HEIGHT FALLS COULD OVERSPREAD THE CNTRL/SRN PLAINS SUN IF THE ECMWF IS CORRECT. THIS SCENARIO WOULD ALSO SUPPORT A THREAT FOR ORGANIZED SEVERE THUNDERSTORMS PRE-DRYLINE...ALONG/SOUTH OF WARM FRONT. DETAILS BEYOND DAY5 ARE JUST TOO UNCERTAIN REGARDING CONVECTIVE EVOLUTION AND MOISTURE/INSTABILITY FLUXES. ..DARROW.. 03/16/2011 CLICK TO GET WUUS48 PTSD48 PRODUCT Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 16, 2011 Share Posted March 16, 2011 30% implied certainty, if I'm not mistaken. Yes, a 30% probs are needed for a risk after D3. I'm kind of surprised to see a D4 risk of 30%. Link to comment Share on other sites More sharing options...
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