CalUWxBill
04-04-2005, 09:32 PM
We had to do this for our Synoptic Met II class, I figured I'd post it here. I may have needed to extend more severe weather into east Texas, but here it is.
Convective Outlook Days 1 and 2 - Effective 8Z 5 April 2005
Day 1 12Z 5 April 2005 to 12Z 5 April 2005
Day 2 12Z 6 April 2005 to 12Z 7 April 2005
Current Synoptic Setup:
Polar front jet shows distinct trough-ridge-trough pattern which is split from the zonal flow of the sub-tropical jet that now stretches from the central Baja California through Mexico and across the southern gulf states. Deepening negatively tilted trough exists across the Intermountain West with vortmax centered over southeast Nevada and western Arizona, this vortmax is southeast of another potent shortwave in Oregon that is set to phase up with it. Strong trough entry jet max should allow the trough to rapidly deepen and close off with time. The positive vorticity advection associated with this fast moving and developing trough should allow for the development of lee cyclogenesis lee of the Rocky Mountains and setup a common Colorado type low that will enter the Plains with alot of punch. Typically these lows will develop rapidly off the high plains then weaken and occlude fairly quickly as well.
Underlying Model Prognostication:
Good agreement exists between the 18Z NAM and GFS as of this point, looks like the GFS may be having a better handle on development of the lee low. The upper level low will close off and secondary vortmax that rotates around closed low may be a crucial factor in the development of severe weather across the central Gulf Coast states into Wednesday night. AFWA MM5 is also in agreement with these models but better distinguishes active frontal convection with that associated with vortmax and cold pool of 500mb closed low.
Day 1 Severe Weather Outlook:
Since models were in good agreement AFWA MM5 model was used to distinguish best areas of convective activity for day 1. No organized severe weather is expected until around 21Z 16CST Tuesday. At that point as the upper level low winds up and sfc low has fully developed, 850 mb temps are shown to cool off rapidly through out the day, while surface temperature warm considerably due to daytime heating. This is combined with a dryline that progresses from the sfc up to 850 mb and develops in the eastern third of Oklahoma, Kansas and Northeastern Texas. This should spark a line of potentially severe thunderstorms, with a high likelihood of tornadic activity. The greatest threat will move into western Arkansas, with a large likelihood in MO and LA as well. Also severe weather is set to develop along the northern and western edges of the dry tongue before it wraps around and closes off the deepening 500 mb trough. Due to the strongest portion of the dryline at 850, it seems likely that greatest likelihood of large hail will be in the Ozarks region of western Oklahom and Arkansas into southern Missouri and northern Arkansas as well as in the higher elevation areas of Kansas and Nebraska high plains. Highest thunderstorm related winds will occur in the Arkansas area in association with strong 30+kt low level jet. A strong backside jet will also develop and may interact with storms develop along wrap around dry tongue, this would produce a high likelihood of severe winds across southern Nebrasika, northern and west-central Kansas.
Day 2 Severe Weather Outlook:
Day 2 initially begins with thunderstorms winding up over the mid-Mississippi valley as the day progresses upper level dynamics weaken as low becomes cut off from polar jet flow. A persistent low-level jet will remain, without the upper level support, this low-level flow will still develop some strong helicity values especially progged at 00Z the 7th along the MS/Al Gulf coast border, a line should develop northeast from this area. Also an area of increased cape will occur under the closed low, sfc heating should help spark convective activity. Some mid-level dry air may work in but soundings suggest driest air should be over northwest Georgia and northern Alabama, greatest probability of hail will be expected in this area, with some hail also be possible under the cold pool region of the upper level low situated over Arkansas. There is some suggestion of tornadic activity with low-level helicity values, however without strong upper level support, the development of tornadic supercells will be played down. Keeping chance storms into mid-missippi valley, Tennessee and lower Ohio valley's, with the slight risk over much of the southeast. While severe weather is certainly possible we feel the criteria for moderate risk has not been achieved except along the immediate Gulf Coast.
http://home.comcast.net/~bscheftic/tornado.jpg
http://home.comcast.net/~bscheftic/hail.jpg
http://home.comcast.net/~bscheftic/wind.jpg
http://home.comcast.net/~bscheftic/convective.jpg
Convective Outlook Days 1 and 2 - Effective 8Z 5 April 2005
Day 1 12Z 5 April 2005 to 12Z 5 April 2005
Day 2 12Z 6 April 2005 to 12Z 7 April 2005
Current Synoptic Setup:
Polar front jet shows distinct trough-ridge-trough pattern which is split from the zonal flow of the sub-tropical jet that now stretches from the central Baja California through Mexico and across the southern gulf states. Deepening negatively tilted trough exists across the Intermountain West with vortmax centered over southeast Nevada and western Arizona, this vortmax is southeast of another potent shortwave in Oregon that is set to phase up with it. Strong trough entry jet max should allow the trough to rapidly deepen and close off with time. The positive vorticity advection associated with this fast moving and developing trough should allow for the development of lee cyclogenesis lee of the Rocky Mountains and setup a common Colorado type low that will enter the Plains with alot of punch. Typically these lows will develop rapidly off the high plains then weaken and occlude fairly quickly as well.
Underlying Model Prognostication:
Good agreement exists between the 18Z NAM and GFS as of this point, looks like the GFS may be having a better handle on development of the lee low. The upper level low will close off and secondary vortmax that rotates around closed low may be a crucial factor in the development of severe weather across the central Gulf Coast states into Wednesday night. AFWA MM5 is also in agreement with these models but better distinguishes active frontal convection with that associated with vortmax and cold pool of 500mb closed low.
Day 1 Severe Weather Outlook:
Since models were in good agreement AFWA MM5 model was used to distinguish best areas of convective activity for day 1. No organized severe weather is expected until around 21Z 16CST Tuesday. At that point as the upper level low winds up and sfc low has fully developed, 850 mb temps are shown to cool off rapidly through out the day, while surface temperature warm considerably due to daytime heating. This is combined with a dryline that progresses from the sfc up to 850 mb and develops in the eastern third of Oklahoma, Kansas and Northeastern Texas. This should spark a line of potentially severe thunderstorms, with a high likelihood of tornadic activity. The greatest threat will move into western Arkansas, with a large likelihood in MO and LA as well. Also severe weather is set to develop along the northern and western edges of the dry tongue before it wraps around and closes off the deepening 500 mb trough. Due to the strongest portion of the dryline at 850, it seems likely that greatest likelihood of large hail will be in the Ozarks region of western Oklahom and Arkansas into southern Missouri and northern Arkansas as well as in the higher elevation areas of Kansas and Nebraska high plains. Highest thunderstorm related winds will occur in the Arkansas area in association with strong 30+kt low level jet. A strong backside jet will also develop and may interact with storms develop along wrap around dry tongue, this would produce a high likelihood of severe winds across southern Nebrasika, northern and west-central Kansas.
Day 2 Severe Weather Outlook:
Day 2 initially begins with thunderstorms winding up over the mid-Mississippi valley as the day progresses upper level dynamics weaken as low becomes cut off from polar jet flow. A persistent low-level jet will remain, without the upper level support, this low-level flow will still develop some strong helicity values especially progged at 00Z the 7th along the MS/Al Gulf coast border, a line should develop northeast from this area. Also an area of increased cape will occur under the closed low, sfc heating should help spark convective activity. Some mid-level dry air may work in but soundings suggest driest air should be over northwest Georgia and northern Alabama, greatest probability of hail will be expected in this area, with some hail also be possible under the cold pool region of the upper level low situated over Arkansas. There is some suggestion of tornadic activity with low-level helicity values, however without strong upper level support, the development of tornadic supercells will be played down. Keeping chance storms into mid-missippi valley, Tennessee and lower Ohio valley's, with the slight risk over much of the southeast. While severe weather is certainly possible we feel the criteria for moderate risk has not been achieved except along the immediate Gulf Coast.
http://home.comcast.net/~bscheftic/tornado.jpg
http://home.comcast.net/~bscheftic/hail.jpg
http://home.comcast.net/~bscheftic/wind.jpg
http://home.comcast.net/~bscheftic/convective.jpg