andyhb Posted October 22, 2012 Share Posted October 22, 2012 Well, here's a sample sounding from the 00z NAM at Albert Lea, MN. Link to comment Share on other sites More sharing options...
ZackH Posted October 22, 2012 Share Posted October 22, 2012 As you were posting that Andy, I was just looking closer at SSE MN... Its a different and more interesting story there. Link to comment Share on other sites More sharing options...
ZackH Posted October 22, 2012 Share Posted October 22, 2012 I'd chase that... south of Mankato, MN. http://www.twisterdata.com/index.php?sounding.lat=44.2137&sounding.lon=-93.9771&prog=forecast&model=NAM&grid=221&model_yyyy=2012&model_mm=10&model_dd=22&model_init_hh=00&fhour=69¶meter=CAPE&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false&sounding=y&sndclick=y Link to comment Share on other sites More sharing options...
andyhb Posted October 22, 2012 Share Posted October 22, 2012 I'd chase that... south of Mankato, MN. http://www.twisterda...ng=y&sndclick=y Right on the warm front. Link to comment Share on other sites More sharing options...
MnWeatherman Posted October 22, 2012 Share Posted October 22, 2012 If it goes any more east, I'm out...SW Wisconsin is a nightmare to chase. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted October 22, 2012 Author Share Posted October 22, 2012 Not going to lie, this three piece ejection/positive tilt western US trough is a big waste of a nice cold air dump courtesy the Alaska blockfest. Link to comment Share on other sites More sharing options...
Buckeye05 Posted October 22, 2012 Share Posted October 22, 2012 ...MIDDLE MO VALLEY/UPPER MIDWEST/UPPER MS VALLEY... CURRENT INDICATIONS ARE THAT RELATIVELY WEAK INHIBITION MAY EXIST WITHIN A RELATIVELY MOIST /LOWER 60 F SURFACE DEWPOINTS/ AND POTENTIALLY UNSTABLE /MLCAPE TO 1000-1500 J PER KG/ AIRMASS TO THE EAST OF THE AFOREMENTIONED COLD FRONT/DEVELOPING SURFACE LOW. HOWEVER...THE LIKELIHOOD/EXTENT OF SURFACE BASED CONVECTIVE DEVELOPMENT THROUGH PEAK HEATING IS A BIT UNCERTAIN...ESPECIALLY GIVEN INITIALLY MODEST BROAD SCALE FORCING FOR ASCENT AND THE POSSIBILITY OF RESIDUAL CAPPING ALOFT VIA AN ELEVATED MIXED LAYER. HOWEVER...ANY SURFACE BASED DEVELOPMENT THAT DOES DEVELOP/MATURE THROUGH LATE AFTERNOON/EARLY EVENING COULD POSE A SEVERE RISK GIVEN AMPLE VERTICAL SHEAR/INSTABILITY. WITH SUPERCELLS AT LEAST CONDITIONALLY POSSIBLE...THIS COULD INCLUDE SEVERE HAIL/WIND AND PERHAPS SOME TORNADO POTENTIAL ACROSS PORTIONS OF IA/SOUTHERN MN INTO NORTHWEST WI. OF GREATER LIKELIHOOD WILL BE FOR CONVECTION TO INCREASE WEDNESDAY NIGHT NEAR MUCH OF THE EASTWARD-SHIFTING FRONTAL ZONE...AS FORCING FOR ASCENT APPRECIABLY INCREASES LATE WEDNESDAY INTO THURSDAY WITH AID OF LARGE SCALE HEIGHT FALLS AND A COUPLED UPPER JET. WITH INCREASING FORCING FOR ASCENT/VERTICAL SHEAR...SUFFICIENT MOISTURE/INSTABILITY ATTENDANT TO THE FRONTAL ZONE WILL ALLOW FOR THE POSSIBILITY OF AT LEAST SPORADIC SEVERE HAIL AND PERHAPS STRONG/SEVERE WIND GUSTS DURING THE EVENING. A CATEGORICAL SLIGHT RISK MAY BE WARRANTED FOR PORTIONS OF THE REGION IN SUBSEQUENT OUTLOOKS AS DETAILS BECOME BETTER REFINED. Link to comment Share on other sites More sharing options...
andyhb Posted October 23, 2012 Share Posted October 23, 2012 NAM still showing a solid area around SE MN/NE IA and SW WI around 18-00z Wednesday evening. Link to comment Share on other sites More sharing options...
andyhb Posted October 23, 2012 Share Posted October 23, 2012 DAY 2 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT TUE OCT 23 2012 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MS VALLEY/MIDDLE MO VALLEY... ...SYNOPSIS... AN EASTWARD-SHIFTING LONGWAVE TROUGH WILL BE PREVALENT OVER THE WESTERN HALF OF THE CONUS ON WEDNESDAY. STEADY HEIGHT FALLS ARE EXPECTED OVER THE UPPER MIDWEST AND UPPER MS VALLEY ON THE PERIPHERY OF A CLOSED/LEAD PORTION OF THE UPPER TROUGH OVER THE CENTRAL CANADIAN PRAIRIES. STEADY SURFACE CYCLOGENESIS IS ANTICIPATED ESPECIALLY INTO WEDNESDAY NIGHT ACROSS THE UPPER MS VALLEY AND CENTRAL HIGH PLAINS...WITH A STRONG COLD FRONT BECOMING INCREASINGLY DEFINED IN A NORTHEAST-SOUTHEAST ORIENTATION ACROSS THE UPPER MIDWEST/UPPER MS VALLEY TO THE CENTRAL PLAINS BY WEDNESDAY NIGHT. ...MIDDLE MO VALLEY/UPPER MIDWEST/UPPER MS VALLEY... HEATING/DESTABILIZATION AND INCREASINGLY WEAK INHIBITION IS EXPECTED NEAR/JUST AHEAD OF THE NORTHEAST-SOUTHWEST ORIENTED COLD FRONT AND DEVELOPING SURFACE LOW WEDNESDAY AFTERNOON. BENEATH A RELATIVELY STEEP PLUME OF MID LEVEL LAPSE RATES...LOWER 60S F SURFACE DEWPOINTS MAY CONTRIBUTE TO AS MUCH AS 1500-2500 J/KG MLCAPE BY PEAK HEATING. HOWEVER...THE LIKELIHOOD/EXTENT OF SURFACE BASED CONVECTIVE DEVELOPMENT THROUGH PEAK HEATING REMAINS UNCERTAIN...ESPECIALLY GIVEN INITIALLY MODEST BROAD SCALE FORCING FOR ASCENT AND THE POSSIBILITY OF RESIDUAL CAPPING ALOFT VIA THE ELEVATED MIXED LAYER. HOWEVER...ANY DEVELOPMENT THAT DOES OCCUR/MATURE THROUGH LATE AFTERNOON/EARLY EVENING COULD POSE A SURFACE BASED SEVERE RISK GIVEN AMPLE VERTICAL SHEAR/INSTABILITY...WITH SUPERCELLS AT LEAST CONDITIONALLY POSSIBLE. THIS COULD INCLUDE SEVERE HAIL/WIND AND SOME TORNADO POTENTIAL ACROSS PORTIONS OF IA/SOUTHERN MN INTO WESTERN WI. A GREATER LIKELIHOOD WILL BE FOR CONVECTION TO INCREASE IN EARNEST WEDNESDAY NIGHT NEAR MUCH OF THE EASTWARD-SHIFTING FRONTAL ZONE FROM THE UPPER MS VALLEY TO THE CENTRAL PLAINS. THIS WILL BE AS FORCING FOR ASCENT APPRECIABLY INCREASES LATE WEDNESDAY INTO THURSDAY WITH AID OF LARGE SCALE HEIGHT FALLS AND A COUPLED UPPER JET. WITH INCREASING FORCING FOR ASCENT/VERTICAL SHEAR...SUFFICIENT MOISTURE/INSTABILITY ATTENDANT TO THE FRONTAL ZONE WILL ALLOW FOR THE POSSIBILITY OF AT LEAST SPORADIC SEVERE HAIL. SOME STRONG/SEVERE WIND GUSTS MAY ALSO BE POSSIBLE DURING THE EVENING...ALTHOUGH THE UNDERCUTTING NATURE OF THE FRONT SHOULD TEMPER THIS POTENTIAL. ..GUYER.. 10/23/2012 Link to comment Share on other sites More sharing options...
MnWeatherman Posted October 23, 2012 Share Posted October 23, 2012 GFS has slowed up on the last 4 runs. Looks interesting in iowa and se mn. Link to comment Share on other sites More sharing options...
andyhb Posted October 23, 2012 Share Posted October 23, 2012 12z NAM has a nasty environment if the capping does go, man. Link to comment Share on other sites More sharing options...
chase_stormz Posted October 23, 2012 Share Posted October 23, 2012 12z NAM has a nasty environment if the capping does go, man. It sure does, wow! Link to comment Share on other sites More sharing options...
Buckeye05 Posted October 23, 2012 Share Posted October 23, 2012 Some of the Hodographs in IA/WI look pretty good. My gut tells me this could be one of those events that has the potential to be a bit of a surprise if things come together just right. Link to comment Share on other sites More sharing options...
chase_stormz Posted October 23, 2012 Share Posted October 23, 2012 Some of the Hodographs in IA/WI look pretty good. My gut tells me this could be one of those events that has the potential to be a bit of a surprise if things come together just right. Pretty good? Try pretty sick lol! My gut feeling though is it will cap bust. If it doesn't though, look out. Link to comment Share on other sites More sharing options...
ZackH Posted October 23, 2012 Share Posted October 23, 2012 Part of me really wants to made the journey to the SE MN/WI border tomorrow, but its too conditional to justify missing classes I believe. If the cap goes, the hodos are looking really nasty and the instability is really crazy for this time of year this far north. But the conditional nature and the somewhat iffy terrain make it hard to drive 6-7 hours and chase storms east, away from home. If it ends up busting, that's a long long drive back with a lot to do the next day from missing a lot. A triangle from Rochester to La Crosse to Eau Claire looks great to me. The differences between the NAM and GFS instability wise are concerning. Link to comment Share on other sites More sharing options...
andyhb Posted October 23, 2012 Share Posted October 23, 2012 The differences between the NAM and GFS instability wise are concerning. The GFS' low BL temp bias rearing its head once again, comparing the two and with forecast highs from around the area. For instance, the GFS has 65-70 in the La Crosse area tomorrow, the NAM is 5-10 degrees warmer and NWS forecast has 77. If the NAM is right, we have pretty Spring-esque (even later in the season towards Summer) low level thermodynamics with this setup, and in contrast with many setups like that, the 700 mb temperatures aren't overly high. For chasers going in on this, the terrain is definitely a problem, considering it quickly turns ugly east of the SE MN/WI border. Low level shear looks great 18z and after as winds back closer to the warm front. Link to comment Share on other sites More sharing options...
ZackH Posted October 23, 2012 Share Posted October 23, 2012 The GFS' low BL temp bias rearing its head once again, comparing the two and with forecast highs from around the area. For instance, the GFS has 65-70 in the La Crosse area tomorrow, the NAM is 5-10 degrees warmer and NWS forecast has 77. If the NAM is right, we have pretty Spring-esque (even later in the season towards Summer) low level thermodynamics with this setup, and in contrast with many setups like that, the 700 mb temperatures aren't overly high. For chasers going in on this, the terrain is definitely a problem, considering it quickly turns ugly east of the SE MN/WI border. Low level shear looks great 18z and after as winds back closer to the warm front. All very good points. The 18z NAM may have just swayed me a bit. Shear wise, everything is looking better and the instability is still pretty amazing for this time of year. We have 3 other students who are on the verge of going, so it may happen after all depending on the 00z data. The 18z cap is just a bit stronger, but it can definitely be overcome. I think its right at the 14-15 degree C area around 600-650 mb if I remember correctly. This setup is promising to me because the capping and directional shear should keep everything fairly discrete and photogenic should it pop. Link to comment Share on other sites More sharing options...
Buckeye05 Posted October 23, 2012 Share Posted October 23, 2012 I don't know if this applies to MN/WI, but I know that according to Jon Davies, it's not a good idea to use the 700mb rule to judge capping in the far northern states, due to higher land elevation. I may be interpreting this incorrectly so correct me if I am wrong. http://www.jondavies.net/700mbTcap/700mbTcap.htm Link to comment Share on other sites More sharing options...
ZackH Posted October 23, 2012 Share Posted October 23, 2012 I don't know if this applies to MN/WI, but I know that according to Jon Davies, it's not a good idea to use the 700mb rule to judge capping in the far northern states, due to higher land elevation. I may be interpreting this incorrectly so correct me if I am wrong. http://www.jondavies...p/700mbTcap.htm Here, he is talking about the northern High Plains... that's west of 100 deg W. The elevation near this part of MN/WI is fairly low, FWIW (I know you prefaced the statement by saying you don't know if it applies to MN/WI, though). Link to comment Share on other sites More sharing options...
andyhb Posted October 23, 2012 Share Posted October 23, 2012 Here, he is talking about the northern High Plains... that's west of 100 deg W. The elevation near this part of MN/WI is fairly low, FWIW (I know you prefaced the statement by saying you don't know if it applies to MN/WI, though). This. Link to comment Share on other sites More sharing options...
Buckeye05 Posted October 23, 2012 Share Posted October 23, 2012 That makes more sense, always have been unclear on that. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 Due to worries about cloud cover, capping, and instability, we are sitting tomorrow out after all. If you look at the RAP when comparing the NAM... the instability is nowhere close (near the best shear profiles). The RAP looks like cloud cover all day long. On top of that, the NAM generally over-estimated today's temps in the main target area by 5+ degrees. I strongly believe, that if anything gets going, it will be after dark and its too risky for a 6-7 hour drive there and back. Also, the 00z NAM shows stronger capping from what I'm seeing except for right on and above the warm front. If nothing goes up early, it will be shame to see such a waste of wonderful shear parameters. Link to comment Share on other sites More sharing options...
andyhb Posted October 24, 2012 Share Posted October 24, 2012 Due to worries about cloud cover, capping, and instability, we are sitting tomorrow out after all. If you look at the RAP when comparing the NAM... the instability is nowhere close (near the best shear profiles). The RAP looks like cloud cover all day long. On top of that, the NAM generally over-estimated today's temps in the main target area by 5+ degrees. I strongly believe, that if anything gets going, it will be after dark and its too risky for a 6-7 hour drive there and back. Also, the 00z NAM shows stronger capping from what I'm seeing except for right on and above the warm front. If nothing goes up early, it will be shame to see such a waste of wonderful shear parameters. *Sigh* This year...again. I'm not so sure it's the NAM overdoing temps (although with clouds, this will definitely play a role as well) as much as it is the WF being significantly farther south on the RAP, at least to my eyes. Link to comment Share on other sites More sharing options...
brettjrob Posted October 24, 2012 Share Posted October 24, 2012 *Sigh* This year...again. I'm not so sure it's the NAM overdoing temps as much as it is the WF being significantly farther south on the RAP, at least to my eyes. Sure looks that way to me, too. At 21z the front bisects IA from SW-NE and has cleared all of MN save the farthest SE corner. This wouldn't be the first time in 2012 this mode of failure has reared its head. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 Oh I agree that could very well be the case. I just observed that the NAM had overestimated the temps in the target area today... there may be nothing to it, but I just can't miss class for it. If it had been a weekend, I'd already be there no matter what. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 Yup, the RAP would make Iowa the place to be. The cap isn't terrible there but if the RAP were to verify it would simply be too far south and east for me to make the trip on a school day. Link to comment Share on other sites More sharing options...
andyhb Posted October 24, 2012 Share Posted October 24, 2012 Yup, the RAP would make Iowa the place to be. The cap isn't terrible there but if the RAP were to verify it would simply be too far south and east for me to make the trip on a school day. Yeah, looking at IA, I do see potential, although not for you, so I might still have something to keep tabs on (other than the relentless model wars of the NE/Sandy doldrums), although I guess we'll see what the SPC thinks in a few minutes. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 I am surprised that there is such a spread on WF and mesolow location with the NAM and RAP this close to the event. Link to comment Share on other sites More sharing options...
andyhb Posted October 24, 2012 Share Posted October 24, 2012 The SPC WRF suggests the WF gets further north, and well, this Updraft Helicity product speaks for itself... http://www.emc.ncep....yle/spcprod/00/ NSSL WRF screws it up with a bunch of junk, which prevents anything more substantial from going up. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 Yup, the updraft helicity there looks pretty nasty around the border at 00z. Link to comment Share on other sites More sharing options...
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