22 Oct KSDF forecast

posted Oct 22, 2012, 2:19 PM by Michael Baldwin   [ updated Oct 22, 2012, 2:24 PM ]
moving on to the next city: Louisville, KY, closest city to Purdue that we'll see this year

current obs/SPC mesoanalysis showing a large anticyclone parked to the SE of KSDF and a plume of high dewpoints that has advanced as far north as KLAF this afternoon in the wake of the MCS that moved across IL/IN today.  Satellite showing some cirrus across southern IN near what's left of that MCS. Dewpoints in northern KY are actually lower than here in central IN, lower/mid/50s with temps in the upper 70s/low 80s in the region.  Last night's low was around 60, not expecting much change tomorrow compared to today looking at temps/thicknesses, so current guidance calling for upper 50s for a min seems reasonable.  Similar argument can be made for max temp, persistence should be a decent forecast (near 80), consistent with guidance values.  Precip is an issue tomorrow, NAM and 12Z Purdue WRF showing next short-wave trof/vort max heading into Missouri tonight, WRF develops another MCS tonight and takes the remnants of that predicted system over northern KY during the day tomorrow.  There is currently some convection over OK just ahead of this vort max.  CAPE values are high across Missouri, and shear will likely increase as the mid-level speed max moves into that region tonight.  Not finding much support for the WRF's forecast in the latest HRRR, but it seems reasonable to me to expect another round of MCS development overnight tonight, whether the remains of that system will hold together long enough to bring some precip to KSDF is yet another tough question.  If that does occur, it could hold down their max temp a couple of degrees, the WRF doesn't bring those remnants through until late in the afternoon.  A few more knots of max wind would likely be the case if this scenario does in fact come true.  Given the low POPs in guidance values (and NWS) I doubt too many people will have precip in their forecast, so my prediction of consensus is 80/59/12kt/0.00".  I'm not sure if the payoff is worth the risk in terms of buying into the WRF's solution for some light precip, so I'm leaning towards zero and maybe knocking a degree off of the max figuring there might be some clouds later in the afternoon given the PVA with this short-wave trough.
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