Thundersnow12 Posted October 12, 2012 Share Posted October 12, 2012 Doubtful if a major serial derecho does get going. with 40kt of 0-1km that is certainly a possibility if things play out favorably Link to comment Share on other sites More sharing options...
Stebo Posted October 12, 2012 Share Posted October 12, 2012 Doubtful if a major serial derecho does get going. Yeah, I wouldn't be downplaying this one at all, Chicago is certaining highlighting it for a good reason. Link to comment Share on other sites More sharing options...
turtlehurricane Posted October 12, 2012 Share Posted October 12, 2012 Strong Pacific jet ramming into the cutoff low over California so it's beginning to move, first bit of flow with an eastward component crossing the Rockies and starting the cyclogenesis process. http://mapmaker.aos.wisc.edu/scr3/sat/west/westwvflash.html Link to comment Share on other sites More sharing options...
Thundersnow12 Posted October 12, 2012 Share Posted October 12, 2012 Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 12, 2012 Share Posted October 12, 2012 I'll defer to the experts but i'm not seeing a major serial derecho in the cards Link to comment Share on other sites More sharing options...
hm8 Posted October 12, 2012 Share Posted October 12, 2012 Not sure about this one. IMO I'm not seeing a full on derecho materializing. That being said, even just a weakish line of showers/t-showers could be enough to bring down some significant gusts, so it still could get interesting. Link to comment Share on other sites More sharing options...
Powerball Posted October 12, 2012 Share Posted October 12, 2012 If nothing else, I can definitely see some High Wind Warnings going out for the GL/OV on Sunday. Ideally, everything would need to slow down JUST a couple more hours for it to take advantage of peak heating ,but with the 60kts at 850mb and the Vort Max moving through there's no question that we're going to see widespread 45-60 MPH wind gusts outside of convection. As far as the Mississippi Valley and Upper Midwest, I don't forsee an actual derecho (a term that's thrown around way too loosely), mostly because the winds are parallel to the front (normally I like to see strong due westerly UL winds when looking for an ideal derecho setup). If any portion of the squall line bows out and picks up the forward propagating speed, it will be the portion in Central/Southern Illinois as it presses into Indiana Saturday night/Sunday morning. That said, any mode of convection in this setup can likely produce strong derecho-like winds (due to downward momentum). Link to comment Share on other sites More sharing options...
Hoosier Posted October 12, 2012 Author Share Posted October 12, 2012 The NAM has a tongue of lower dewpoints (can be seen best by looking at 850 mb dewpoints...it runs from central IL SSWrd at 6z Sunday). Anyone know what is causing that? Link to comment Share on other sites More sharing options...
Stebo Posted October 12, 2012 Share Posted October 12, 2012 The NAM has a tongue of lower dewpoints (can be seen best by looking at 850 mb dewpoints...it runs from central IL SSWrd at 6z Sunday). Anyone know what is causing that? Drier air at 850mb rounding the base of the ridge, I would question if it is overdone though. especially considering all the moist air surrounding it. Link to comment Share on other sites More sharing options...
Stebo Posted October 12, 2012 Share Posted October 12, 2012 Some strong wording from Grand Rapids with their AFD I AM BECOMING INCREASINGLY CONCERNED ABOUT POTENTIAL FOR A FEW STRONG TO SEVERE STORMS SATURDAY. BULK SHEAR VALUES WILL BE WAY UP AROUND 50 TO 55 KTS. HIGH 0-1 AND 0-3 SRH VALUES ARE EXPECTED ESPECIALLY NEAR TO JUST NORTH OF THE SFC WARM FRONT AND LOW LCL HEIGHTS ARE LIKELY IN THAT SAME AREA. THIS SITUATION WILL NEED TO BE MONITORED VERY CLOSELY FOR POTENTIAL FOR AN ISOLATED TORNADO. THIS IN ADDITION TO MORE GENERAL SEVERE WX THREATS SUCH AS ELEVATED STORMS WITH HAIL AND STORMS WITH STRONG WINDS AND LOCALLY HEAVY RAINFALL. THE WARM FRONT SHOULD MAKE A STRONGER PUSH NORTHWARD SATURDAY NIGHT AND FOCUS MOST OF THE RAIN AND THUNDERSTORMS ACROSS NORTHERN TO NORTH CENTRAL LOWER MI. THIS ACTIVITY SHOULD IMPACT OUR NORTHERN COUNTIES WITH A THREAT FOR HEAVY RAINFALL AS 1000-850 MB MOISTURE TRANSPORT RAMPS UP CONSIDERABLY SATURDAY NIGHT ALONG WITH THE NOCTURNAL LLJ STRENGTHENING FURTHER TO 50-55 KTS BY 12Z SUN. THEN FOR SUNDAY ALL OF OUR FCST AREA WILL LIKELY BE IN THE WARM SECTOR WITH THE APPROACHING SFC LOW AND COLD FRONT BRINGING POTENTIAL FOR A SQUALL LINE ALONG OR JUST AHEAD OF THE FRONT WITH BOWING SEGMENTS. IN ADDITION BULK SHEAR VALUES OF 40-50 KTS ARE SUPPORTIVE OF POTENTIAL FOR A FEW SUPERCELLS BOTH EMBEDDED WITHIN THE SQUALL LINE AND OUT AHEAD OF IT FROM 12Z SUNDAY THROUGH (AT LEAST) MID AFTN SUNDAY UNTIL THE FRONT CLEARS OUR AREA. SB CAPES WILL LIKELY ONLY REACH 500 TO LESS THAN A 1000 J/KG. EVEN SO THIS IN CONJUNCTION WITH FAVORABLE BULK SHEAR WOULD BE SUFFICIENT AS SHEAR WILL COMPENSATE FOR RELATIVELY WEAK INSTABILITY. ALSO... IT IS NOTED 00Z ECMWF IS A BIT SLOWER WITH THE COLD FRONTAL PASSAGE. SO IT COULD WELL END UP THAT THE COLD FRONT WILL NOT CLEAR OUR AREA UNTIL SUNDAY EVENING... WHICH HAS IMPLICATIONS FOR THE SVR WX THREAT OVER OUR AREA THAT WOULD LINGER UNTIL THEN. THE MAIN MITIGATING FACTOR GOING AGAINST SVR WX POTENTIAL SUNDAY WILL BE THE LACK OF STRONGER SFC BASED INSTABILITY. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 12, 2012 Share Posted October 12, 2012 As expected LOT not impressed....instability just not there Link to comment Share on other sites More sharing options...
Hoosier Posted October 12, 2012 Author Share Posted October 12, 2012 NAM really trying to put emphasis on a second low. Interesting wrinkle but it is the NAM after all lol Link to comment Share on other sites More sharing options...
Hoosier Posted October 12, 2012 Author Share Posted October 12, 2012 Significant differences in the instability progs for tomorrow. NAM has about 1000 J/kg CAPE in N IL at 00z while the GFS has much less. GFS is keeping temps in the low-mid 60s while the NAM is more like 65-70. Link to comment Share on other sites More sharing options...
andyhb Posted October 12, 2012 Share Posted October 12, 2012 Significant differences in the instability progs for tomorrow. NAM has about 1000 J/kg CAPE in N IL at 00z while the GFS has much less. GFS is keeping temps in the low-mid 60s while the NAM is more like 65-70. I' tend to think the NAM has a more realistic view of the thermodynamics compared to the GFS, considering the GFS has a persistent low BL temp bias. Link to comment Share on other sites More sharing options...
Hoosier Posted October 12, 2012 Author Share Posted October 12, 2012 I' tend to think the NAM has a more realistic view of the thermodynamics compared to the GFS, considering the GFS has a persistent low BL temp bias. It might... and it's not like 65-70 is wildly unrealistic. Link to comment Share on other sites More sharing options...
Thunder Road Posted October 13, 2012 Share Posted October 13, 2012 I' tend to think the NAM has a more realistic view of the thermodynamics compared to the GFS, considering the GFS has a persistent low BL temp bias. Didn't the most recent upgrade fix this? Link to comment Share on other sites More sharing options...
andyhb Posted October 13, 2012 Share Posted October 13, 2012 Didn't the most recent upgrade fix this? Looking at verification for the past couple of days, it appears not very much. Link to comment Share on other sites More sharing options...
PatrickSumner Posted October 13, 2012 Share Posted October 13, 2012 Was hoping that the SPC would push SLIGHT risk further north for Sunday but they are sticking to there guns. Oh well... Link to comment Share on other sites More sharing options...
Powerball Posted October 13, 2012 Share Posted October 13, 2012 Looks like the NAM has gone back to the stronger solution. It has a decent squall line blasting across OH/IN Sunday afternoon, with 40-45kts of wind shear around 925mb across MI/OH/IN/SW ON. Even if there's no convection, or if any convection's not severe, most areas that get into the warm sector will still probably see non-t'storm wind gusts greater than 50 MPH. Link to comment Share on other sites More sharing options...
cyclone77 Posted October 13, 2012 Share Posted October 13, 2012 Was hoping that the SPC would push SLIGHT risk further north for Sunday but they are sticking to there guns. Oh well... They're too far south with the northern extent of the slight. No doubt that will be expanded north on later outlooks. As expected northwest IL went from 30% probs to barely in the eastern end of the slight. Link to comment Share on other sites More sharing options...
Stebo Posted October 13, 2012 Share Posted October 13, 2012 They're too far south with the northern extent of the slight. No doubt that will be expanded north on later outlooks. As expected northwest IL went from 30% probs to barely in the eastern end of the slight. I think that in later outlooks NW IL will be upped the problem is that it will probably after dark action. I also agree with respect to Sunday and the Northern parts of the outlook or lack there of. Link to comment Share on other sites More sharing options...
IWXwx Posted October 13, 2012 Share Posted October 13, 2012 Looks like the NAM has gone back to the stronger solution. It has a decent squall line blasting across OH/IN Sunday afternoon, with 40-45kts of wind shear around 925mb across MI/OH/IN/SW ON. Even if there's no convection, or if any convection's not severe, most areas that get into the warm sector will still probably see non-t'storm wind gusts greater than 50 MPH. I'm kind of surprised that neither IND or IWX put up wind advisories for tomorrow. I guess they are waiting one more forecast cycle. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 13, 2012 Share Posted October 13, 2012 Yeah, severe threat is very slim as expected....heavy rain threat looking better and better. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 13, 2012 Share Posted October 13, 2012 micro cell just went up over MBY Link to comment Share on other sites More sharing options...
Stebo Posted October 13, 2012 Share Posted October 13, 2012 Pretty solid non-severe complex over Iowa now, should move ENE and eventually E toward Chicago and Lower Michigan. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 13, 2012 Share Posted October 13, 2012 Pretty solid non-severe complex over Iowa now, should move ENE and eventually E toward Chicago and Lower Michigan. the latest NAM is a real soaker for the region...I think some of the further north solutions are going to be hard to come by if the front stays so convectively active. Expecting 1.5" or so for MBY Link to comment Share on other sites More sharing options...
Stebo Posted October 13, 2012 Share Posted October 13, 2012 the latest NAM is a real soaker for the region...I think some of the further north solutions are going to be hard to come by if the front stays so convectively active. Expecting 1.5" or so for MBY Possible, though I think considering the magnitude of the LLJ, I think the front should at least lift into Chicago and into Southern Lower Michigan. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 13, 2012 Share Posted October 13, 2012 going to use this for general storm talk since severe threat is low Link to comment Share on other sites More sharing options...
BowMeHunter Posted October 13, 2012 Share Posted October 13, 2012 euro with the low overhead so we have a little wiggle room south and would really be in the real sweet spot and wouldn't have to worry about the dreaded se mi dry slot. Link to comment Share on other sites More sharing options...
Hoosier Posted October 13, 2012 Author Share Posted October 13, 2012 I'm kind of surprised that neither IND or IWX put up wind advisories for tomorrow. I guess they are waiting one more forecast cycle. I'd bet $$ that it will be coming soon. The 12z runs would put some areas near high wind warning criteria. Even going conservative would mean that advisory criteria shouldn't be too difficult. Link to comment Share on other sites More sharing options...
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