TUESDAY EVENING UPDATE: I am not liking the look of the EML in southern KS Thursday afternoon and into the evening hours, albeit if a supercell goes along the dryline it has extreme potential to be violent. I am becoming a little more focused on an area a little closer to home based on this evenings NAM-WRF and SREF.....would like to see a couple more model runs before I bite on it....but I am thinking my chase on Thursday will not be in south central Kansas....at least based on the data I am looking at tonight...look for an update tomorrow on the blog.
OLD DISCUSSION (MONDAY EVENING)
INITIAL TARGET LOCATION: Blackwell, OK
DISCUSSION:
A surface low over north central North Dakota with a cold front stretching back to the Rio Grande Valley will interact with a deep surface low forecasted to be in central Kansas by 0Z/30 and be the setup for severe thunderstorms in the central plains. A warm front will extend from the northern area of low pressure through southern MN back into the Ohio Valley. A dryline will also be associated with this setup in north central Oklahoma and extend back into central TX. Here is a look at the forecasted surface map at 0Z/30.
A 300mb 110 to 120 knot jet is forecasted to be rounding the base of the trough at 0Z/30. Embedded within this jet is an 80 knot jet streak nosing into west central OK and edging into south central KS just west of the I-35 corridor. This system, without a doubt, has plenty of shear to work with, but will it have all of the other ingredients for a severe weather setup?
The GFS and NAM-WRF both show a negatively tilted trough ejecting out into the plains and into northern TX at 0Z/30. Overall bulk shear from the surface to 500mb is well over 60kts. The 850mb and 500mb crossovers are favorable for supercells, no matter how short lived they are!
700mb temps do not look to be an issue as far as EML goes. Any forcing at all should be able to erode any cap by mid to late afternoon, especially as the dryline mixes to the east.
700mb UVV's are appreciable along the I-35 corridor from Wichita, KS to Oklahoma City, OK
A significant 850mb jet of 60 to 70kts running parallel to the surface features will make the storm motions horrendous and nearly unable to chase safely! Storm motions are forecasted to be from the southwest at well over 45 kts, especially along the northern edge of the cold front where it has already overtaken the dryline. Further south things may remain more discrete for a little longer period of time due to low level shear being better in the southern play. I still think one will need to set up in their preferred target area and let the storms come racing to you!!
850mb dewpoints are appreciable with a very apparent dry slot nosing into southwestern and south central Kansas at 0Z/30.
Surface temperatures are forecasted to be in the mid to upper 70's over the target area. SELY surface winds will be slightly backed at 0Z/30 which may enhance the tornado threat across southern KS and northern OK, at least early on in the evolution of the system.
Moisture return into the target areas is a bit questionable at this time, but feel low to mid 60 dewpoints can be realized during the afternoon on Thursday. I do see a nice dryline bulge in SW/SC KS at 0Z/30 which may become a factor as models continue to show consistency in the moisture return. The surface moisture will be the key to determine if this dryline will become a factor in this severe weather setup.
CAPE values are modest in the 1000 to 1500 J/KG range on both model runs, especially along and just west of the I-35 corridor from Wichita, KS to Oklahoma City, OK
The CINH and EML, may indeed be a factor, but I still believe with the upper air dynamics and forcing from the arrival of the dryline/cold front will erode any cap by mid to late afternoon on Thursday.
EHI is maximized over southern KS and northern/central Oklahoma at 0Z/30. This is basically along and west of the I-35 corridor from Wichita, KS to Oklahoma City, OK. Overall helicity values are maximized in northern and central Oklahoma.
The NAM-WRF is showing the cold front breaking out precip from southern South Dakota to the Red River in Texas by 0Z/30.
Here is a quick look at the SKEW-T and Hodo for Ponca City, OK at 0Z/30:
I anticipate discrete cells firing ahead of the dryline in southern KS, northern and central Oklahoma by mid to late afternoon before they are overtaken by the advancing cold front. I look for the predominant storm mode to be linear with embedded supercells, especially farther north in Kansas, with the possibility of discrete supercells further south, most likely a tail end charlie play.
For this forecast, I have discounted the ECMWF, which has a slower solution, albeit a more favored one, for a blend of the NAM-WRF and GFS. The NAM-WRF and GFS have come into better agreement the last few model runs, whereas the ECMWF is slower by 24 hours or so! I will be watching this setup as we move toward Thursday but it has all of the ingredients, except for moisture right now, to be a decent severe setup in the central plains.
OLD DISCUSSION (MONDAY EVENING)
INITIAL TARGET LOCATION: Blackwell, OK
DISCUSSION:
A surface low over north central North Dakota with a cold front stretching back to the Rio Grande Valley will interact with a deep surface low forecasted to be in central Kansas by 0Z/30 and be the setup for severe thunderstorms in the central plains. A warm front will extend from the northern area of low pressure through southern MN back into the Ohio Valley. A dryline will also be associated with this setup in north central Oklahoma and extend back into central TX. Here is a look at the forecasted surface map at 0Z/30.
The GFS and NAM-WRF both show a negatively tilted trough ejecting out into the plains and into northern TX at 0Z/30. Overall bulk shear from the surface to 500mb is well over 60kts. The 850mb and 500mb crossovers are favorable for supercells, no matter how short lived they are!
700mb temps do not look to be an issue as far as EML goes. Any forcing at all should be able to erode any cap by mid to late afternoon, especially as the dryline mixes to the east.
700mb UVV's are appreciable along the I-35 corridor from Wichita, KS to Oklahoma City, OK
A significant 850mb jet of 60 to 70kts running parallel to the surface features will make the storm motions horrendous and nearly unable to chase safely! Storm motions are forecasted to be from the southwest at well over 45 kts, especially along the northern edge of the cold front where it has already overtaken the dryline. Further south things may remain more discrete for a little longer period of time due to low level shear being better in the southern play. I still think one will need to set up in their preferred target area and let the storms come racing to you!!
850mb dewpoints are appreciable with a very apparent dry slot nosing into southwestern and south central Kansas at 0Z/30.
Surface temperatures are forecasted to be in the mid to upper 70's over the target area. SELY surface winds will be slightly backed at 0Z/30 which may enhance the tornado threat across southern KS and northern OK, at least early on in the evolution of the system.
Moisture return into the target areas is a bit questionable at this time, but feel low to mid 60 dewpoints can be realized during the afternoon on Thursday. I do see a nice dryline bulge in SW/SC KS at 0Z/30 which may become a factor as models continue to show consistency in the moisture return. The surface moisture will be the key to determine if this dryline will become a factor in this severe weather setup.
CAPE values are modest in the 1000 to 1500 J/KG range on both model runs, especially along and just west of the I-35 corridor from Wichita, KS to Oklahoma City, OK
The CINH and EML, may indeed be a factor, but I still believe with the upper air dynamics and forcing from the arrival of the dryline/cold front will erode any cap by mid to late afternoon on Thursday.
EHI is maximized over southern KS and northern/central Oklahoma at 0Z/30. This is basically along and west of the I-35 corridor from Wichita, KS to Oklahoma City, OK. Overall helicity values are maximized in northern and central Oklahoma.
The NAM-WRF is showing the cold front breaking out precip from southern South Dakota to the Red River in Texas by 0Z/30.
Here is a quick look at the SKEW-T and Hodo for Ponca City, OK at 0Z/30:
I anticipate discrete cells firing ahead of the dryline in southern KS, northern and central Oklahoma by mid to late afternoon before they are overtaken by the advancing cold front. I look for the predominant storm mode to be linear with embedded supercells, especially farther north in Kansas, with the possibility of discrete supercells further south, most likely a tail end charlie play.
For this forecast, I have discounted the ECMWF, which has a slower solution, albeit a more favored one, for a blend of the NAM-WRF and GFS. The NAM-WRF and GFS have come into better agreement the last few model runs, whereas the ECMWF is slower by 24 hours or so! I will be watching this setup as we move toward Thursday but it has all of the ingredients, except for moisture right now, to be a decent severe setup in the central plains.
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