Memphis Weather Posted June 12, 2013 Share Posted June 12, 2013 I thought it was policy for watches within a high risk to be PDS, although I understand the conundrum here. Patrick Marsh (of SPC) has been tweeting about it some today... He says the policy only mandates severe t'storms watches on a High Risk/wind day be PDS. A tornado watch for 15% would not necessarily dictate it. Since tornado watches are much more likely, it may or may not necessitate PDS just depending on how the tornado threat evolves. He noted he understands the confusion and that it's a policy that should be re-looked at. Link to comment Share on other sites More sharing options...
andyhb Posted June 12, 2013 Share Posted June 12, 2013 PDS Tornado Watches only when the high risk probabilities are for tornadoes. Otherwise it is the forecaster's discretion. Yeah I guess if we see an unexpectedly longer length of a discrete dominant mode, then that would more support that idea. Link to comment Share on other sites More sharing options...
OceanStWx Posted June 12, 2013 Share Posted June 12, 2013 I'd think (I don't know) that a 'garden variety' tornado probs tornado watch with wind or hail that would merit a PDS Severe Watch would be PDS. Seems the logical way. But that doesn't mean its the way it is. How many offices are doing 17Z or 18Z balloons? DVN has one up in the air now. Haven't seen any others for sure. Link to comment Share on other sites More sharing options...
MidwestChaser Posted June 12, 2013 Share Posted June 12, 2013 79/70 in Addison. Sun peeking through more readily now. Link to comment Share on other sites More sharing options...
Hoosier Posted June 12, 2013 Author Share Posted June 12, 2013 DVN has one up in the air now. Haven't seen any others for sure. THought I saw that ILX is doing one too. Link to comment Share on other sites More sharing options...
Drizzle Posted June 12, 2013 Share Posted June 12, 2013 Sitting at 80/71 here in Dekalb, 2 miles north of 88 and 10 east of 39. Link to comment Share on other sites More sharing options...
Gilbertfly Posted June 12, 2013 Share Posted June 12, 2013 THought I saw that ILX is doing one too. yes 18Z Link to comment Share on other sites More sharing options...
Superstorm93 Posted June 12, 2013 Share Posted June 12, 2013 New 12z NCAR WRF ARW has tornadic supercells breaking out soon around Iowa All of the action absolutely nails the Chicago metro area with supercells and line segments Dangerous day today: Link to comment Share on other sites More sharing options...
Jim Marusak Posted June 12, 2013 Share Posted June 12, 2013 THought I saw that ILX is doing one too. too bad maybe omaha couldn't do one as well, as well as maybe some school there in des moines sending up an experimental one, to see if that ridge in central IA is as warm as is being depicted. Link to comment Share on other sites More sharing options...
Geos Posted June 12, 2013 Share Posted June 12, 2013 Socked in with clouds again. Wind direction still ESE. Link to comment Share on other sites More sharing options...
andyhb Posted June 12, 2013 Share Posted June 12, 2013 New 12z NCAR WRF ARW has tornadic supercells breaking out soon around Iowa All of the action absolutely nails the Chicago metro area with supercells and line segments Dangerous day today: dbze.hr07.png dbze.hr10.png Wow that is impressive...I mean that cluster of supercells in IA would be in a very volatile environment (and then move downstream). Link to comment Share on other sites More sharing options...
OceanStWx Posted June 12, 2013 Share Posted June 12, 2013 DVN in through 400 mb on AWIPS. Still capped (as we should expect) but wind field is pretty impressive. Nearly 45 kts of southwesterly flow at 850 mb. Link to comment Share on other sites More sharing options...
Hoosier Posted June 12, 2013 Author Share Posted June 12, 2013 Link to comment Share on other sites More sharing options...
magoos0728 Posted June 12, 2013 Share Posted June 12, 2013 A chill to the air here, but it still feels muggy...clouds too. Link to comment Share on other sites More sharing options...
Hoosier Posted June 12, 2013 Author Share Posted June 12, 2013 DVN in through 400 mb on AWIPS. Still capped (as we should expect) but wind field is pretty impressive. Nearly 45 kts of southwesterly flow at 850 mb. Is it me or was the low level flow not progged to be nearly that strong there? Link to comment Share on other sites More sharing options...
Superstorm93 Posted June 12, 2013 Share Posted June 12, 2013 10m Winds Link to comment Share on other sites More sharing options...
andyhb Posted June 12, 2013 Share Posted June 12, 2013 Is it me or was the low level flow not progged to be nearly that strong there? Well the last mesoanalysis update had 25-35 kts in that area so to the nearest term, it doesn't appear so. Link to comment Share on other sites More sharing options...
OceanStWx Posted June 12, 2013 Share Posted June 12, 2013 Looks like a gravity wave feature possibly on visible moving ESE along the IA/MN border, just about at MCW right now. Link to comment Share on other sites More sharing options...
Chinook Posted June 12, 2013 Share Posted June 12, 2013 RAP-analyzed deep moisture convergence (SPC mesoanalysis) is about as high as I've ever seen it. Link to comment Share on other sites More sharing options...
Memphis Weather Posted June 12, 2013 Share Posted June 12, 2013 No surprise but... AREAS AFFECTED...PORTIONS OF CENTRAL/ERN IA...SWRN WI...NWRN ILCONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELYVALID 121749Z - 121845ZPROBABILITY OF WATCH ISSUANCE...95 PERCENTSUMMARY...A TORNADO WATCH WILL BE COORDINATED WITH LOCAL NWS WEATHERFORECAST OFFICES PRIOR TO 19Z. SVR TSTMS ARE EXPECTED TO DEVELOPOVER PORTIONS OF NORTHERN/EASTERN IA AND NORTHWEST ILLINOIS THISAFTERNOON AND QUICKLY BECOME SEVERE WITH A RISK FORTORNADOES...LARGE HAIL AND DAMAGING WINDS.DISCUSSION...SURFACE MESOANALYSIS AT 17Z INDICATES AN AREA OF LOWPRESSURE OVER CENTRAL IOWA AND A FRONTAL BOUNDARY EXTENDING EASTWARDALONG THE ILLINOIS/WISCONSIN BORDER. LATEST VISIBLE SATELLITEIMAGERY SHOWS A DEVELOPING CU FIELD AS DIABATIC HEATING REDUCESMLCINH. TOWERING CU EVIDENT WEST/NW OF DES MOINES SUGGESTS THATCONVECTIVE INITIATION MAY OCCUR WITHIN THE NEXT FEW HOURS. THEENVIRONMENT IS CHARACTERIZED BY MODERATE/STRONG INSTABILITY WITHMLCAPES RANGING FROM 2000 J/KG OVER CENTRAL IOWA TO NEAR 4000 J/KGOVER EASTERN IOWA/NORTHWEST ILLINOIS. STRONG DEEP-LAYER SHEAR ISPREVALENT WITH 50-60 KNOTS OVER THE DISCUSSION AREA. LOW-LEVEL /0-3KM/ SRH FROM THE DAVENPORT VWP OF NEAR 300 M2/S2 SUGGESTS THATLOW-LEVEL ROTATION IS POSSIBLE WITH ANY DISCRETE STORM THAT DOESDEVELOP.AS AN UPPER LEVEL IMPULSE APPROACHES FROM THE WEST THIS AFTERNOONAND PROVIDES ADDITIONAL FORCING FOR ASCENT...SEVERE THUNDERSTORMSARE EXPECTED TO DEVELOP RAPIDLY NEAR THE SURFACE FRONT ANDINTENSIFYING SURFACE LOW PRESSURE. LOW-LEVEL FLOW WILL BACK WITHTIME LATER THIS AFTERNOON NORTHEAST OF THE SURFACE LOW...FURTHERAUGMENTING LOW-LEVEL SRH.TORNADOES...LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITHSUPERCELLS DEVELOPING IN THE DISCUSSION AREA...WITH THE POSSIBILITYFOR A STRONG TORNADO DURING THE FIRST FEW HOURS AFTER INITIATION.WITH TIME...UPSCALE GROWTH IS ANTICIPATED AS THE STORMS MOVE EASTWITH ENHANCED DAMAGING WIND/EMBEDDED MESOVORTEX TORNADO THREATS.A TORNADO WATCH WILL BE COORDINATED WITH LOCAL NWS WEATHER FORECASTOFFICES PRIOR TO 19Z...BUNTING/CARBIN.. 06/12/2013 Link to comment Share on other sites More sharing options...
Chitown Storm Posted June 12, 2013 Share Posted June 12, 2013 Lots of sun here in lisle near 88 and 355. Temps rising and the humidity is definitely uncomfortable. There's a weird feeling outside. Link to comment Share on other sites More sharing options...
MidwestChaser Posted June 12, 2013 Share Posted June 12, 2013 Tornado watch incoming. http://kamala.cod.edu/offs/KWNS/1306121750.acus11.html Link to comment Share on other sites More sharing options...
andyhb Posted June 12, 2013 Share Posted June 12, 2013 Looks like a gravity wave feature possibly on visible moving ESE along the IA/MN border, just about at MCW right now. Yup, the clouds are becoming increasingly fragmented further east towards Chicagoland as well. Link to comment Share on other sites More sharing options...
OceanStWx Posted June 12, 2013 Share Posted June 12, 2013 There it is, not much in the way of obs to peruse for pressure data, but it is there and propagating ESE. Link to comment Share on other sites More sharing options...
MidwestChaser Posted June 12, 2013 Share Posted June 12, 2013 That's going to help storms fire? Link to comment Share on other sites More sharing options...
mjwise Posted June 12, 2013 Share Posted June 12, 2013 RAP-analyzed deep moisture convergence (SPC mesoanalysis) is about as high as I've ever seen it. Check out the 850mb moisture transport graphs and the precip placement graph. The latter is almost unreadable. EDIT: The bullseye is about 24. EDIT: The mesoanalysis site is like a candy store right now. Supercell composite and derecho composites vaulting upwards. The MCS maintenance index is 90+ all the way east into PA! Link to comment Share on other sites More sharing options...
OceanStWx Posted June 12, 2013 Share Posted June 12, 2013 That's going to help storms fire? It could. There will be alternating rising and sinking motion if that is a gravity wave. The rising motion could be enough to erase a small remaining cap. This is the process that helped kick off the supercell that produced the Parkersburg tornado. Link to comment Share on other sites More sharing options...
Indystorm Posted June 12, 2013 Share Posted June 12, 2013 I just noticed the mid level lapse rate of 8.5 from Chambana over to LAF. Hate to get hit with those hailstones later today. Link to comment Share on other sites More sharing options...
Castaway Posted June 12, 2013 Share Posted June 12, 2013 Suns beating nicely. Uncomfortably Humid. Link to comment Share on other sites More sharing options...
Hoosier Posted June 12, 2013 Author Share Posted June 12, 2013 http://weather.admin.niu.edu/forecast.txt Link to comment Share on other sites More sharing options...
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