All Weather News

More Monster Snows, Tornadoes & Flooding

27 Mar 2009, 3:28 pm
The severe thunderstorms we discussed would occur this week certainly have not let us down, and today is another day with an elevated threat, where the SPC has issued a Moderate Risk in their Convective Outlook category including the areas of northern Louisiana, southern Arkansas, and most of Mississippi, including the Mississippi Delta where wonderful food, great people, and excellent chasing territory predominate. Much of the southeast from Oklahoma to Georgia are under a “Slight” risk classification, however such an issuance should not be taken lightly as often severe thunderstorms and tornadoes occur under such a heading.

Remnants of yesterday’s activities are slowly moving out of the southeast where three possible tornadoes were reported in the Florida Panhandle, but the main threat for today will be in the area outlined above later this afternoon and this evening.

The threats today revolve around the same issues we have discussed all week, with the addition of a greater variance in the atmospheric column between the warm gulf air at lower levels and cooler air associated with our moving system aloft. This will result in heightened thermodynamic forcing with the likelihood today of very large hail, the usual threat of winds and strong tornadoes. The storms will become supercellular this afternoon forming into disorganized linear structures as the evening progresses.

Day One Convective Outlook

Blizzard Still Going, More Systems To Come
We discussed our triple threat scenario and the developing systems over the last week or so, our current low is certainly performing up to expectations, and the threat of mixed precipitation we forecast seems to be right on track.

Today we will utilize our usual graphics to discuss where our current storm will go, and where those in the future may approach.

3.5 Day Ptype Animation
7.5 Day Minimum Temps
7.5 Day Ptype Anim
7.5 Day Maximum Temps

The first frame of our 12z 3.5 Day Precipitation Type Animation is valid 11am this morning, clearly depicting that ending at that time a respectable area of mixed precipitation is possible on a line running from near Lubbock, through Childress and into western Oklahoma, while snows still predominate in the Texas Panhandle, Cherokee Strip, western Kansas, southeastern Colorado, and eastern New Mexico.

The second frame valid at 2pm EDT extends the potential for mixed precipitation in Oklahoma and even into southern Kansas, while snows are still favored for the previous regions.

Advancing through to F021 Valid 5am EDT tomorrow, our low is shown to accelerate through northeastern Oklahoma with snows trailing along the southwestern flank, and from here she begins a faster move to the northeast.

F036hr Valid 8pm EDT we see a twinge of an area near Chicago showing the potential for mixed precipitation while snows are still falling in northeastern Oklahoma, southeastern Texas through Missouri and into Iowa. As we advance a few frames through 5am on Sunday, the snow band becomes more clearly defined with snows covering the majority of Illinois, eastern Missouri, Wisconsin, and into Michigan, where the potential for mixed exists over the previous hours.

By F051hr 11am EDT on Sunday snow is still in the cards for Chicago, Indiana, and Michigan, but also take a look to the west. Do you see something we’ve mentioned a few times developing? =)

By 8pm Sunday evening, our first low is nearly finished with us, with lingering snows possible in Ohio, Michigan, and of course the Ridge-and-Valley provinces of the Mid Atlantic states. While the second low of our triple threat scenario is showing itself in the Rockies. Go ahead and fast forward through F075hr, 11am EDT on Monday Morning and notice the second low centered in Nebraska with snows running through both Dakotas, southeastern Montana, and eastern Wyoming.

By the last forecast hour (F084) for our 3.5 Day animation valid 8pm EDT Monday Evening, the second low is still in northeastern Nebraska with a forecast central pressure of 995mb, with snows still trailing through both Dakotas, central and western Nebraska and lighter snows possible in the fringes.

OK, so now we are through 8pm EDT next Monday morning, from here pull up our 7.5 Day Precipitation Type Animation where we left off previously, so F084hr Valid 8pm EDT on Monday March 30. Notice that the low is forecast to be in a similar position, with a wider band of snows possible since as you recall this product is at 6 hour intervals instead of 3. So where does it go from here?

Interestingly, it seems Minnesota may have have an attractive force, as we advance through 8pm EDT on Tuesday morning, it is centered on the border of Minnesota and Iowa with a forecast central pressure of 994mb. By 8pm next Tuesday, central pressure rises slightly while the low centers itself over Rochester. But do you see anything else starting to develop? =)

Threat 3 begins forming at the frame above, but advance through F120hr valid 8am EDT next Wedesday, where it appears it may wish to become another ‘Dodge City Low.’ However, forward through 8pm on Wednesday (F132), notice how she digs like we previously forecast to become perhaps another Panhandle hook.

To give you an idea where this low is heading, forward all the way through next Friday April 3, (F168hr) at 8am EDT. She looks to dig deeply doesn’t she, all the way to 980mb! However, recall i’ve mentioned before that often times the vertical stacking, or depth of central pressure often fluctuates with models especially out this far, but it surely could be interesting! Notice Minnesota is in the line of fire again.

The last frame we can utilize is F180hr valid 8pm EDT next Friday where the third low in our triple threat scenario eases up to 985mb, but notice closely the division of snow and rain.

Additionally what’s going on off the coast of British Columbia on the last frame? =)

Snow accumulations with our first low will continue to be respectable where totals of up to 1 foot in portions of Oklahoma and Kansas are easily obtainable. As she turns to the northeast there we be a very long swath of 6″ snows running through Kansas, Missouri, and into Illinois. The interesting thing will be the totals once she reaches Chicago.. very tough to tell. I am going to say the best totals look to be from Oak Park to the north and east, where 6″ would be a good bet. South of Oak Park on a line from say Naperville to Aurora, perhaps 4-6″. It will be interesting to see how it pans out and if the models change their minds over the next few days.

The icing we mentioned is certainly in the cards for many areas, but the best chance for accumulation is in Oklahoma, Kansas and northwestern Missouri today, as well as a splinge in northern Illinois, not to forget the potential we mentioned in Michigan coming up.

Flooding is still going insane for the north. Our forecast yesterday still hold true, or simply utilize our fantastic Rivers & Lakes Center mentioned in yesterday’s post to view live and updated conditions.

Please be sure to view our Advisory and Radar Centers for the latest updates and developments.

As always stay tuned to your favorite weather outlet, stay informed, and stay safe!



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