A great setup looming today in northeast Colorado between the Cheyenne Ridge and the Palmer Divide!
Looks like by late afternoon into the evening the cap will erode and upslope flow will allow the development of discrete supercell thunderstorms east of Denver.. The 4km WRF is definitely on board with this, and shows 3 discrete supercells across the area!
Long story short, enough instability, combined with favorable wind shear, should yield some nice shots later today! I am pretty stoked about the potential for beautiful supercells and some tornadoes..
Friday, May 21, 2010
Tuesday, May 18, 2010
Severe Weather Outbreak Tomorrow In Oklahoma!
After an active severe weather evening across Colorado and Texas, another interesting severe weather event is shaping up for tomorrow afternoon.
By Mid Afternoon Thursday a sharp dryline will be found across western Oklahoma southward into central Texas.. Surface dewpoints of 65+ will be found along the moist side of the boundary. To the north a warm front will likely be draped across the KS/OK border, but the exact location will ultimately be a result of morning convection ongoing from tonight.
In the mid levels, a 500mb jet streak will be found crossing the dryline bulge, with the left exit region of mid level jet co located across the region.
Convergence along the boundary and a well timed shortwave should ignite convection across the northern part of the dryline by late afternoon. Shear values of 60+ kts with vectors perpendicular to the boundary should yield discrete storm activity. Kinematic and instability profiles will largely be supportive of supercells with VERY large hail possible, owing to steep low and mid level lapse rates and dry air in the mid levels.
Along the boundary, tornadoes are a good threat, due to enhanced low level shear and deep moisture in place. As the evening draws closer, an increasing low level jet feature will also aid in the tornado threat.
Initial Target : Watonga, OK
Might post another forecast in the morning, or while on the road.. On the road right now, hence the lack of more detail.
-Brandon
By Mid Afternoon Thursday a sharp dryline will be found across western Oklahoma southward into central Texas.. Surface dewpoints of 65+ will be found along the moist side of the boundary. To the north a warm front will likely be draped across the KS/OK border, but the exact location will ultimately be a result of morning convection ongoing from tonight.
In the mid levels, a 500mb jet streak will be found crossing the dryline bulge, with the left exit region of mid level jet co located across the region.
Convergence along the boundary and a well timed shortwave should ignite convection across the northern part of the dryline by late afternoon. Shear values of 60+ kts with vectors perpendicular to the boundary should yield discrete storm activity. Kinematic and instability profiles will largely be supportive of supercells with VERY large hail possible, owing to steep low and mid level lapse rates and dry air in the mid levels.
Along the boundary, tornadoes are a good threat, due to enhanced low level shear and deep moisture in place. As the evening draws closer, an increasing low level jet feature will also aid in the tornado threat.
Initial Target : Watonga, OK
Dew Point Forecast
500mb Wind/Height Forecast
Sounding From Watonga, OK @ 00z Thurs
-Brandon
Wednesday, May 12, 2010
Severe Weather Possible Again 5/12/10
A somewhat less broadcast, but still decent severe threat exists across portions of Oklahoma, Kansas, Missouri and Illinois tomorrow afternoon.
A large upper level trough will begin to lift out of the plains Wednesday afternoon. As this happens a surface low pressure system will move eastward across Misourri.
The first forecast challenge revolves around the eventual location of the warm front. Currently, MCS formation is occuring over Kansas. Overnight, this MCS will translate eastward across the warm front. Ultimately, this may act to limit the northward progression of the warm front tomorrow afternoon..
The next forecast challenge is the forecast capping inversion that should limit convective development for much of the day.
During the late afternoon, indications of a subtle mid level shortwave, combined with upper level divergence from an upper level jet speed maxima, may provide just enough to fuel thunderstorm development.
If thunderstorms develop, the post frontal environment features high CAPE values owing to significant moisture transport, and diurnal heating. 0-6KM shear values of 60+ KTS will be favorable for supercell thunderstorms..
At this time I would anticipate heading into Misourri during the late afternoon and evening.. With so much uncertainty however, I will wait before making any real target.
A large upper level trough will begin to lift out of the plains Wednesday afternoon. As this happens a surface low pressure system will move eastward across Misourri.
The first forecast challenge revolves around the eventual location of the warm front. Currently, MCS formation is occuring over Kansas. Overnight, this MCS will translate eastward across the warm front. Ultimately, this may act to limit the northward progression of the warm front tomorrow afternoon..
The next forecast challenge is the forecast capping inversion that should limit convective development for much of the day.
During the late afternoon, indications of a subtle mid level shortwave, combined with upper level divergence from an upper level jet speed maxima, may provide just enough to fuel thunderstorm development.
If thunderstorms develop, the post frontal environment features high CAPE values owing to significant moisture transport, and diurnal heating. 0-6KM shear values of 60+ KTS will be favorable for supercell thunderstorms..
At this time I would anticipate heading into Misourri during the late afternoon and evening.. With so much uncertainty however, I will wait before making any real target.
Monday, May 10, 2010
Overview of 5/10/10 Tornado Outbreak
A significant severe weather outbreak occurred today across portions of Kansas, Oklahoma and Texas. Numerous significant tornadoes have been reported with significant damage being noted across many areas. I would like to discuss in better detail below, the setup that lead to such an event.
To do a sort of top down approach we see that a strong upper level trough was located across the area, with the KS/OK region lying underneath a zone of divergence.
H25 Shows a Deep, Powerful Trough.
500mb was characterized by ~60-70 KTS flow.. With the region under the favorable exit region of the mid level jet axis.
Cold Air advection was also occuring in the mid levels, most notable at H5. This helps enhance updraft strength and enhance vertical vorticity.
As we approach 700mb we see a shortwave rounding the base of the trough that would contribute to storm development in the afternoon hours.
850 shows an impressive low level jet advecting copius moisture into the target area.
At the surface, extreme instability developed rapidly in the wake of morning convection. The pre dryline environment was characterized by 65 degree dewpoints and southerly surface winds. In a theta e rich environment, and impressive wind fields the atmosphere was primed for supercell development.
A special 20z Sounding from KOUN showed an impressive environment conducive for significant severe weather.
* Note the strong veering wind profile, and impressive upper atmospheric support. CAPE values approaching 4000 J/KG.. Cold air advection @ mid levels.. Dry Air @700mb.
Ahead of the dryline, strong forcing and upper air support aided in the development of supercell thunderstorms. Along the OK/KS border supercells developed first, and quickly went tornadic.
Further south along the dryline, more supercell storms erupted later as the previously mentioned shortwave passed through the area. Incredible low level storm relative helicity promoted enhanced low level rotation. This combined with sufficient low level moisture served to enhance the tornado threat. Shear vectors perpendicular to the boundary kept supercells discrete for an extended period of time.
Here is a radar grab from the supercell that produced significant damage in the Oklahoma City/Norman area!
In closing, an incredible combination of impressive wind fields at all levels, combined with sufficient forcing, and upper support for thunderstorm development, and a moisture laden, theta e rich surface environment, combined for a potent outbreak of tornadic supercells that caused significant damage in some locales.
In closing, an incredible combination of impressive wind fields at all levels, combined with sufficient forcing, and upper support for thunderstorm development, and a moisture laden, theta e rich surface environment, combined for a potent outbreak of tornadic supercells that caused significant damage in some locales.
Situation Update: 5/10/10 KS/OK 19z
Extreme instability is developing as forecast along and south of the warm front as it surges to the north. The pre dryline environment is appearing very favorable for supercell development in the next few hours across central and northern Oklahoma, where 64-66 degree Td's have made it across the region. The region lies under the left exit region of a strong upper level jet, associated UA divergence, combined with impressive forcing and increasing moisture convergence should ignite storms in the next few hours in central Oklahoma..
Impressive shear values with shear vectors aligned perpendicular to the dryline should promote discrete supercell development. Low level features and upper level wind fields are favorable for strong tornadoes. The tornadic threat may increase even more after initiation however.. Storm motions of 50kts could support the threat for long track tornadoes.. In addition, impressive low/mid level lapse rates should favor very large hail across the area with any supercell.
A PDS Tornado has been issued.
Expect continued development in the next few hours.
Impressive shear values with shear vectors aligned perpendicular to the dryline should promote discrete supercell development. Low level features and upper level wind fields are favorable for strong tornadoes. The tornadic threat may increase even more after initiation however.. Storm motions of 50kts could support the threat for long track tornadoes.. In addition, impressive low/mid level lapse rates should favor very large hail across the area with any supercell.
A PDS Tornado has been issued.
Expect continued development in the next few hours.
Severe Thunderstorm Outbreak Still Appearing Likely! 5/10/10
Well it appears as though in reality the NAM did verify from last night in that it holds the warm front well to the south..1515 satellite imagery shows clouds still draped over the area which has served to limit destabilization thus far today.
RUC Guidance however that impressive rapid destabilization will occur south of the warm front this afternoon, in a theta e rich environment.. CAPE values upwards of 3000 J/KG should be found across the risk area by late this afternoon!
A shortwave rounding the base of the upper level trough should ignite supercell thunderstorms along the boundary during the afternoon. Shear vectors perpendicular to the dryline, and impressive deep layer shear values should promote discrete supercell activity.
The threats from these supercells include very large hail owing to impressive low and mid level lapse rates, and strong tornadoes. The threat for strong tornadoes exists due to impressive helicity values in the warm sector in the pre dryline environment. Impressive wind fields will also promote rapid storm movement to the ENE, thus the threat for long track tornadoes exists as well.
My target as of right now would be Tonkawa, OK..
RUC Guidance however that impressive rapid destabilization will occur south of the warm front this afternoon, in a theta e rich environment.. CAPE values upwards of 3000 J/KG should be found across the risk area by late this afternoon!
A shortwave rounding the base of the upper level trough should ignite supercell thunderstorms along the boundary during the afternoon. Shear vectors perpendicular to the dryline, and impressive deep layer shear values should promote discrete supercell activity.
The threats from these supercells include very large hail owing to impressive low and mid level lapse rates, and strong tornadoes. The threat for strong tornadoes exists due to impressive helicity values in the warm sector in the pre dryline environment. Impressive wind fields will also promote rapid storm movement to the ENE, thus the threat for long track tornadoes exists as well.
My target as of right now would be Tonkawa, OK..
Severe Weather Outbreak Today Across KS/OK (5/10/10)
A potent severe weather situation is setting up in the nest 24 hours across portions of Oklahoma and Kansas.
The synoptic setup will feature a shortwave trough over the four corner regions that will advance eastward through the MO valley. A strong upper level trough will be found across the region with 70-80 KT westerly H5 flow to be found across the southern portions of the target area.. At the surface a ~996mb low will be found across southwestern KS near DDC by 21z Monday.
Morning convection should be ongoing at the start of the morning period in response to a strong low level jet and associated deep moisture transport, these storms should be mainly elevated capable of hail as they move off to the northeast, on the eastern periphery of a translating elevated mixed layer.
In the wake of morning convection, models show rapid destabilization occurring in response to increasing theta e transport downstream of a H5 vorticity maximum, and impressive cold advection in the mid levels. >65Td's should be well established by mid afternoon in the pre dry line environment.
Upper level divergence associated with the left exit region of mid level jet, aided by impressive forcing and diurnal heating and instability should spark a few isolated supercells on the northern edge of the dryline, immediately east of the surface low, across southern and central Kansas. Here, low and mid level wind profiles favor strong supercell potential, in a region characterized by 50kts 0-6 KM Deep layer shear below impressive H5 jet streak and ~90kt H25 flow.
Further south along the dryline into central Oklahoma, development will be more contingent upon the shortwave progged to cross the region in the late afternoon hours. In this region, impressive shear values and incredibly steep lapse rates will favor supercells with extremely large hail, and the potential for strong tornadoes. LCL levels of >700m will be found across the dryline. In addition, storm motions of 45-55 MPH will lead to the potential for long track tornadoes as well.
At this time my preliminary target area would be very near Wichita, KS..
The synoptic setup will feature a shortwave trough over the four corner regions that will advance eastward through the MO valley. A strong upper level trough will be found across the region with 70-80 KT westerly H5 flow to be found across the southern portions of the target area.. At the surface a ~996mb low will be found across southwestern KS near DDC by 21z Monday.
Morning convection should be ongoing at the start of the morning period in response to a strong low level jet and associated deep moisture transport, these storms should be mainly elevated capable of hail as they move off to the northeast, on the eastern periphery of a translating elevated mixed layer.
In the wake of morning convection, models show rapid destabilization occurring in response to increasing theta e transport downstream of a H5 vorticity maximum, and impressive cold advection in the mid levels. >65Td's should be well established by mid afternoon in the pre dry line environment.
Upper level divergence associated with the left exit region of mid level jet, aided by impressive forcing and diurnal heating and instability should spark a few isolated supercells on the northern edge of the dryline, immediately east of the surface low, across southern and central Kansas. Here, low and mid level wind profiles favor strong supercell potential, in a region characterized by 50kts 0-6 KM Deep layer shear below impressive H5 jet streak and ~90kt H25 flow.
Further south along the dryline into central Oklahoma, development will be more contingent upon the shortwave progged to cross the region in the late afternoon hours. In this region, impressive shear values and incredibly steep lapse rates will favor supercells with extremely large hail, and the potential for strong tornadoes. LCL levels of >700m will be found across the dryline. In addition, storm motions of 45-55 MPH will lead to the potential for long track tornadoes as well.
At this time my preliminary target area would be very near Wichita, KS..
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