David Reimer Posted May 5, 2014 Share Posted May 5, 2014 The shortwave timing is close to the worst-case scenario, and realistically at this range, it's probably not going to change enough to make a fundamental difference. We go through this so often, and 9 times out of 10, when something looks severely mis-timed even at 120-144 hours, it verifies as such. When it comes to the effect of drought, I've often said that it typically doesn't dictate dryline placement to a huge extent; that to a larger extent, it just modulates vertical mixing (and thus BL moisture quality) of the airmass east of the dryline. I'm starting to question that, though. I don't see any synoptic reason besides drought that the dryline should be positioned so far east on Wednesday, and a similar pattern has emerged several days already this year. If the dryline were closer to the KS/CO border and the Panhandles/SW KS were in play, then perhaps the relatively late arrival of energy Wednesday evening wouldn't be a big problem. So, if we assume drought is partially responsible for the eastward dryline placement, this is just another way it can wreck potential setups. For Thursday, I haven't completely given up, but it's on the rocks. I have to think given the calendar date that the GFS depiction of morning convection completely erasing instability up in IA is overdone, and there should be some potential in that area near the primary sfc low. For OK/TX, things will really hinge on whether a secondary shortwave can pivot through at the right time (and be of sufficient strength). The general pattern with a primary vortmax well north over the central Plains is one that often leads to frustration down here, but every once in awhile comes through (see the Binger/Cordell day in 1981). Honestly I'm hoping we end up with widespread precipitation verses severe weather. Yesterday proved we're in a world of hurt in terms of moisture. If this pattern keeps up we're going to end up with 'fire outbreaks' with each dryline event verses severe weather events. Link to comment Share on other sites More sharing options...
NTXYankee Posted May 5, 2014 Share Posted May 5, 2014 Honestly I'm hoping we end up with widespread precipitation verses severe weather. Yesterday proved we're in a world of hurt in terms of moisture. If this pattern keeps up we're going to end up with 'fire outbreaks' with each dryline event verses severe weather events. Agreed, as much as I love the prospects of seeing a nice southern plains storm, the rain is desperately needed and some nice storms with some heavy rain, even some training of the storms would be a welcome sight by many in these parts. Link to comment Share on other sites More sharing options...
Quixotic1 Posted May 5, 2014 Share Posted May 5, 2014 Honestly I'm hoping we end up with widespread precipitation verses severe weather. Yesterday proved we're in a world of hurt in terms of moisture. If this pattern keeps up we're going to end up with 'fire outbreaks' with each dryline event verses severe weather events. This. We haven't greened up at all this year. First year I can remember that happening. If the summer holds to climo we are going to be hurtin' for certain come October. Link to comment Share on other sites More sharing options...
Ground Scouring Posted May 5, 2014 Author Share Posted May 5, 2014 SPC: ...DISCUSSION...CONSISTENCY BETWEEN MEDIUM-RANGE MODELS APPEARS TO BE HIGH EARLY INTHE PERIOD -- COINCIDENT WITH THE PERIOD OF GREATEST EXPECTED SEVERERISK. THE GFS AND ECMWF BOTH ADVANCE A STRONG SHORT-WAVE FEATURE --THE LEAD IMPULSE WITHIN THE BROADER WRN U.S. TROUGH -- NEWD ACROSSTHE PLAINS STATES TO THE UPPER MS VALLEY REGION DAY 4 /THU.5-8/...AND THEN NEWD ACROSS THE UPPER GREAT LAKES INTO ONTARIO DAY5. WITH THE ASSOCIATED SURFACE LOW ALSO PROGGED TO SHIFT STEADILYNEWD ACROSS THE MID MO TO THE UPPER MS VALLEY DAY 4...AND THEN ONNWD ACROSS ONTARIO TO JAMES BAY THROUGH DAY 5...A TRAILING COLDFRONT WILL SHIFT QUICKLY EWD ACROSS THE CENTRAL U.S. DAY 4 AND THEMIDWEST DAY 5...WHILE ADVANCING MORE SLOWLY WITH SWD EXTENT INTO TX.WITH AN OVERALL DEAMPLIFICATION OF THE UPPER FLOW FIELD OVER THEU.S. AND A MORE STRUNG-OUT SW-NE FRONT INTO DAYS 5-6...SEVERE RISKWOULD APPEAR AT THIS TIME TO LIKELY BE LESS SUBSTANTIAL BEYOND DAY4.FOR DAY 4 HOWEVER -- AS THE POTENT SHORT-WAVE SYSTEM AND ASSOCIATEDCOLD FRONT CROSS THE PLAINS...AN ENHANCED ZONE OF SEVERE RISKREMAINS APPARENT. THOUGH ONGOING CONVECTION EXPECTED AT THE STARTOF THE PERIOD OVER PORTIONS OF THE RISK AREA CONTINUES TO COMPLICATETHE SCENARIO...AMPLE DIURNAL DESTABILIZATION IS EXPECTED AHEAD OFONGOING CONVECTION OVER THE SRN PLAINS VICINITY AS WELL AS WITHIN ADRY SLOT SPREADING NEWD ACROSS THE CENTRAL PLAINS AND MID MO VALLEYTO SUPPORT AN INCREASE IN STORMS THROUGH THE AFTERNOON HOURS. WITHMID-LEVEL SWLYS IN THE 50 TO 70 KT RANGE SPREADING ATOP THE WARMSECTOR...DEGREE OF SHEAR WILL SUPPORT BOTH ORGANIZED/BOWING BANDS OFSTORMS AS WELL AS UPDRAFT ROTATION. ATTM...GREATEST SEVERE RISKSWOULD APPEAR TO BE HAIL AND DAMAGING WINDS...THOUGH A FEW TORNADOESWILL BE POSSIBLE. OVERNIGHT AS CONVECTION SHIFTS EWD/NEWD AND LESSUNSTABLE THERMODYNAMIC CONDITIONS PREVAIL...EXPECT LESSER SEVERERISK TO PREVAIL. Link to comment Share on other sites More sharing options...
Ground Scouring Posted May 5, 2014 Author Share Posted May 5, 2014 And still the trend toward greater instability in N TX / OK / srn KS on Thursday continues with the 06Z GFS bringing the rear entrance region of the H85 jet even closer to the dryline with a deeper secondary low backing the LL winds. Early convection is noticeably less of a problem on this run than on any other run since 12Z yesterday. So the trend is positive for a localized severe threat down there, including tornado potential. I will amend the thread title as a widespread, significant severe outbreak seems unlikely. Link to comment Share on other sites More sharing options...
Ground Scouring Posted May 5, 2014 Author Share Posted May 5, 2014 The 12Z GFS is a bit faster with the shortwave on Wednesday also hints at breaking the cap along the dryline on Wednesday evening in OK. Link to comment Share on other sites More sharing options...
andyhb Posted May 5, 2014 Share Posted May 5, 2014 It's pretty obvious looking at the 700 mb plots from the models that the plume of 700 mb moisture coming up from the E Pac is shrinking the effective warm sector and leading to less than impressive lapse rates. Whether this leads to the complete undoing of the setup, that's still uncertain. Link to comment Share on other sites More sharing options...
andyhb Posted May 5, 2014 Share Posted May 5, 2014 With that said, it does appear that the idea of widespread, crippling convection overnight on Wednesday into Thursday appears to be becoming less prevalent. Link to comment Share on other sites More sharing options...
1900hurricane Posted May 5, 2014 Share Posted May 5, 2014 Honestly, at this point, I'll take some copious heavy rainfall at the expense of chaseable severe weather. The drought is absolutely killing us in Texas and if we don't get some rain now, it's going to be a rough summer. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
OUGrad05 Posted May 6, 2014 Share Posted May 6, 2014 Honestly, at this point, I'll take some copious heavy rainfall at the expense of chaseable severe weather. The drought is absolutely killing us in Texas and if we don't get some rain now, it's going to be a rough summer. Sent from my iPhone as much as I would like to see a good chase day or two we desperately need the rain. This drought is so bad for those in western OK. Sent from my SM-N900V using Tapatalk Link to comment Share on other sites More sharing options...
nrgjeff Posted May 6, 2014 Share Posted May 6, 2014 Thursday could still become a good storm chasing day, but morning rain will make it a nowcast. Looks like two jet streaks coming out. First might enhance chances in Iowa. Second may be the trigger in eastern Kansas. Iowa target seeks more heating. Kansas target requires correct timing of shortwaves and a LLJ recovery after the morning wave. 30% hatched Day 3 often becomes MDT by Day 1, but the jury is still out on MDT placement for Thursday. EDIT: And jury must now consider 12Z data that favors Oklahoma - the hilly regions. No travel plans here. Houston dewpoint still only 60? Link to comment Share on other sites More sharing options...
tornadotony Posted May 6, 2014 Share Posted May 6, 2014 I'm honestly not thrilled with any targets the next two days. Thursday's most interesting play might be in MN/WI, but the wind profiles definitely throw storm mode into question. Link to comment Share on other sites More sharing options...
WxKevinM Posted May 6, 2014 Share Posted May 6, 2014 Well I was thinking of going to the Twin Cities this weekend regardless of storms, so this could be a nice bonus, just would have to leave a day earlier. Link to comment Share on other sites More sharing options...
Chinook Posted May 6, 2014 Share Posted May 6, 2014 If I were doing the virtual storm chase in the next 2 days, I might have a hard time picking a target for either day. Today: a few sheared storms in Nebraska Panhandle/Cheyenne ridge Tomorrow: several 2" hail storms and wind reports from Enid OK to the Big Bend (eastern bend of Rio Grande River), a few scattered hail reports from Sioux City to Minneapolis to central Wisconsin Thursday: If I were to pick somewhere for a likely wind/hail report, it would be tough. KC to southern Texas. I say there should be a 15% risk area KC to southern TX, maybe another 15% risk near Minneapolis/western WI. Link to comment Share on other sites More sharing options...
AgeeWx Posted May 6, 2014 Share Posted May 6, 2014 There could be a couple isolated storms just over the border in WI on thursday afternoon but like Tony alluded to earlier, storm mode is still in question. Shear vectors are iffy and there's the V-B-V issue to consider according to the GFS. Either way, the Northern target doesn't elicit any excitement. Link to comment Share on other sites More sharing options...
OKStorm Posted May 6, 2014 Share Posted May 6, 2014 Thursday could still become a good storm chasing day, but morning rain will make it a nowcast. Looks like two jet streaks coming out. First might enhance chances in Iowa. Second may be the trigger in eastern Kansas. Iowa target seeks more heating. Kansas target requires correct timing of shortwaves and a LLJ recovery after the morning wave. 30% hatched Day 3 often becomes MDT by Day 1, but the jury is still out on MDT placement for Thursday. EDIT: And jury must now consider 12Z data that favors Oklahoma - the hilly regions. No travel plans here. Houston dewpoint still only 60? Link to comment Share on other sites More sharing options...
andyhb Posted May 6, 2014 Share Posted May 6, 2014 Well the 18z NAM's wind profiles would make the triple point/WF setup on Thursday interesting to say the least lol. Silly models aside, I do like how the 12z Euro has a pretty broad area of moderate instability south of the WF earlier in the day on Thursday (around 15z). I'm not sure the quality of the wind profiles that it shows by the time 18z Thurs to 00z Fri rolls around, but considering it shows a broader based upper trough than the GFS, I'd assume it's upper level wind fields are at least marginally more favorable (someone correct me if I'm wrong). Link to comment Share on other sites More sharing options...
andyhb Posted May 7, 2014 Share Posted May 7, 2014 Central MN, using MLCAPE, SB is up near 2800 J/kg. Link to comment Share on other sites More sharing options...
nrgjeff Posted May 7, 2014 Share Posted May 7, 2014 Moisture issues remain. Houston just got to 68 dewpoint this morning. It does not matter what dews are near the target area if the moisture is not deep enough - moisture will mix out. Without even looking at upper air charts, need Houston dewpoint of 72 with 75 preferred. It is a crude and rough, but fairly reliable, way to gauge quality of deep moisture return off the Gulf. SPC keeping a low 5% TOR today is great. Tomorrow appears OK/TX MCS will cut off best moisture return into the central Plains. LLJ could quickly recover if that convection dissipates midday; but, it is forecast to continue all day. If so, even the mighty Plains LLJ will get stuffed. Appears that even Thursday will be sub-par for a May Plains day. I'd give it a shot local, but no way I'd travel to chase that. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 7, 2014 Share Posted May 7, 2014 Moisture issues remain. Houston just got to 68 dewpoint this morning. It does not matter what dews are near the target area if the moisture is not deep enough - moisture will mix out. Without even looking at upper air charts, need Houston dewpoint of 72 with 75 preferred. It is a crude and rough, but fairly reliable, way to gauge quality of deep moisture return off the Gulf. SPC keeping a low 5% TOR today is great. Tomorrow appears OK/TX MCS will cut off best moisture return into the central Plains. LLJ could quickly recover if that convection dissipates midday; but, it is forecast to continue all day. If so, even the mighty Plains LLJ will get stuffed. Appears that even Thursday will be sub-par for a May Plains day. I'd give it a shot local, but no way I'd travel to chase that. Since I am an armchair YouTube chaser, and have never been on a real chase in my life (but am willing to go if invited), I can appreciate incredible downburst winds, like the type that took the roof off the convenience store in West Texas a few years ago, and baseball sized hail. Looking at the 12Z actual soundings from LCH, FWD and CRP, not looking good. DRT has a bit better low level moisture below the cap, looks like moisture might be spreading up the Rio Grande plains. Anyway: NAM sounding in NW Texas, big T/Td spread for the winds, steep mid level lapse rates, and decent speed shear in the mid levels, that could make some YouTube videos. NAM does show precip in area. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 7, 2014 Share Posted May 7, 2014 Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 7, 2014 Share Posted May 7, 2014 Pondering the possibility of heading to C. MN tomorrow. We'll see... Link to comment Share on other sites More sharing options...
mfgmfg Posted May 7, 2014 Share Posted May 7, 2014 Had some golf ball size hail early this morning in Northwest Iowa. More pictures here: http://kiwaradio.com/local-news/rain-and-hail-reports-wednesday-may-7th-2014/ Link to comment Share on other sites More sharing options...
tornadotony Posted May 7, 2014 Share Posted May 7, 2014 Pondering the possibility of heading to C. MN tomorrow. We'll see... Go for it. Liking the triple point more and more for a big tornado or two. Typical IA/MN/SD kind of quasi-cold coreish with enormous instability and shear. Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2014 Share Posted May 7, 2014 Go for it. Liking the triple point more and more for a big tornado or two. Typical IA/MN/SD kind of quasi-cold coreish with enormous instability and shear. Forecast soundings look fairly impressive in that area tomorrow, though the sigtor ingredients isn't really bullish for whatever reason. Link to comment Share on other sites More sharing options...
wotan Posted May 7, 2014 Share Posted May 7, 2014 Moisture issues remain. Houston just got to 68 dewpoint this morning. It does not matter what dews are near the target area if the moisture is not deep enough - moisture will mix out. Without even looking at upper air charts, need Houston dewpoint of 72 with 75 preferred. It is a crude and rough, but fairly reliable, way to gauge quality of deep moisture return off the Gulf. SPC keeping a low 5% TOR today is great. Tomorrow appears OK/TX MCS will cut off best moisture return into the central Plains. LLJ could quickly recover if that convection dissipates midday; but, it is forecast to continue all day. If so, even the mighty Plains LLJ will get stuffed. Appears that even Thursday will be sub-par for a May Plains day. I'd give it a shot local, but no way I'd travel to chase that. The weather in Houston this morning certainly didn't look like what I have come to expect for a plains severe weather outbreak day. Normally I would expect to have a pretty brisk southerly breeze with a lot of cumulus blowing in. This morning was not especially breezy and little in the way of low clouds. It is now overcast here, FWIW. Sent from my jflte using Tapatalk Link to comment Share on other sites More sharing options...
chase_stormz Posted May 7, 2014 Share Posted May 7, 2014 Does anyone have an eye on Saturday as well? Low level winds tend to be a bit weak, but hard to ignore the fact that it has "some" potential. Despite NAM being out of it's range, GFS shows a similar threat. Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 7, 2014 Share Posted May 7, 2014 New SWODY2 mentions possible upgrade for the IA/MN area. Link to comment Share on other sites More sharing options...
soonertrey Posted May 7, 2014 Share Posted May 7, 2014 Does anyone have an eye on Saturday as well? Low level winds tend to be a bit weak, but hard to ignore the fact that it has "some" potential. Despite NAM being out of it's range, GFS shows a similar threat. I'm keeping an eye on Sat, but it's hard to get real excited about it at this point. As you mention, the low level winds are kind of meager. Especially with what the GFS is forecasting. Link to comment Share on other sites More sharing options...
Chinook Posted May 7, 2014 Share Posted May 7, 2014 New SWODY2 mentions possible upgrade for the IA/MN area. MN/IA area is now at 30% risk outlook for tomorrow. The 12z NAM has some huge EHI values over in western Minnesota with about 2500J/kg of CAPE and 200m2/s2 of 3km helicity west of the Twin Cities tomorrow. Link to comment Share on other sites More sharing options...
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