Archive for March, 2009

Updated Storm Chase Plans and Forecast

Posted in Uncategorized with tags , , , , , , , , , on March 28, 2009 by stormstream

It’s late morning and I am still in Atlanta looking things over and trying to figure this thing out. The complex of rain and storms moving across GA, southeast AL and north FL, is really complicating things. I’ve decided it’s just not worth the drive to head to south GA today, so my focus is turning west to Alabama this afternoon along and ahead of the advancing cold front, and where the warm front intersects this front.

The cool pool in the wake of this MCS is significant. It’s chilly in ATL right now with a temperature of only 57. This pool of cool, stable, sinking air is going to keep central and northern GA quiet for much of the day. We are watching for airmass recovery to the west of the complex across AL. Divergence aloft may aid greatly in getting storms going there this afternoon, as well as higher dewpoints and instability.

Shear values increase across GA, so storms may develop in AL this afternoon and then become better organized, and possibly form into supercells as the approach the GA/AL border and move into west-central and southwest GA.

So, here are my revised storms chase and streaming plans for the remainder of the day:

LIVE INTERNET BROADCAST: Broadcasting live on both Severe Studios and Ustream. http://www.severestudios.com/livechase/ and http://ustream.tv/channel/mike-phelps-mobile-weather-stream/ Tune in and ride along with us through the wonders of streaming technology!

TARGET: Columbus, GA to Roanoke, AL to Clanton, AL to Montgomery, AL to Eufaula, AL and back to Columbus, GA.

TIME: Continue to monitor for ATL through the noon hour. If conditions warrant, make a move to get into the target by 3pm.

CONFIDENCE OF SUCCESS LEVEL: Still a low to moderate confidence level in today’s chase opportunities. Still some things to be worked out in the atmosphere before my confidence level rises.

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StormStream Severe Storm Intercept Plan for Saturday, March 28, 2009

Posted in Extreme Weather Video, Severe weather with tags , , , , , , , , , on March 28, 2009 by stormstream

It is quite apparent that I will need to do some driving south and southeast today from my home base near Atlanta, GA if I’m going to be intercepting any decent storms this afternoon and evening. The most unstable air will reside on the south edge and south of an MCS that will move across central GA this morning. Sufficient shear, instability and support aloft will combine to produce and environment favorable for bow echos with damaging wind, and a few supercells capable of producing large hail and isolated tornadoes. The area of greatest threat will reside across southeast AL, the FL panhandle and south and southeast GA. Basically bounded by Troy, AL to Panama City, FL to Jacksonville, FL to Hilton Head, SC.

LIVE BROADCAST PLANS: The plan is to stream this chase live on Severe  Studios at http://www.severestudios.com/livechase/ and also simulcast the stream on Ustream TV at http://www.ustream.tv/channel/mike-phelps-mobile-weather-stream/ Feel free to tune in today and chase with me through the wonders of technology.

TARGET: Rectangle bounded by Bainbridge, GA to Brunswick, GA to Savannah, GA to Georgetown, GA back to Bainbridge.

TIME TO BE IN TARGET: Depart Atlanta by 9am, and be within target by 1pm to allow time for time to either adjust or abort.

CONFIDENCE OF SUCCESS LEVEL: Low to moderate. I’m not really feeling it on this one. It’s worth a shot, but my enthusiasm level for this chase is not high right now. Maybe that will change, but the prospect of driving through hours of rain to get to the target is not an appealing one right now.

If the storms fail me today, at least I may get a nice little mini-vacation to Savannah out of the deal. ūüôā

Severe Weather Threat Increasing through the Night acorss Louisiana, southern Arkansas, southwest Tennessee and Mississippi. Blizzard Continues to Rage across parts of Kansas, Oklahoma and Texas.

Posted in Extreme Weather Video, Severe weather, Winter weather with tags , , , , , , , , , , on March 27, 2009 by stormstream

One round of strong to severe storms with damaging winds and isolated tornadoes rolled across southern MS, AL GA and north FL this morning into the early afternoon.  Those are no longer a threat, and now all eyes turn toward the west across east and northeast TX, southeast OK, southern AR and LA where the next, more significant round, of severe thunderstorms is getting going.  These will sweep eastward through the overnight hours across the areas just mentioned and into southwest TN and MS, producing a dangerous scenario where very dangerous thunderstorms, some producing tornadoes, move across the region in darkness.  This makes an already dangerous event, even that much more dangerous.

This is one of those situations where conditions for severe thunderstorms and tornadoes will actually improve through the overnight hours as wind field increase, and upper level jet energy and dynamics overspread a moist and unstable airmass.  Tornado watches will be issued in progressive order from west to east throughout the night with watches likely as far eastward as western and southwestern Alabama by sunrise Saturday.  Those of you in the danger zone overnight should have an operational weather radio, and take very serious all watches and warnings issued for your area.  It cannot be stressed enough how dangerous this situation is.

By sunrise Saturday there should be an area of severe thunderstorms moving into west-central and southwest AL.  These will produce damaging winds, large hail and tornadoes.  In the 8am to noon time frame, dangerous storms will impact the southern 2/3rds of AL, west-central and southwest GA and into the FL panhandle.  Severe storms will also extend northward across middle TN and even into KY.  Intense and deep convection could develop along the Gulf coast, and if this happens the moisture influx into storms farther north will be disrupted, and there will be a general lessening of the intensity of the event.  However, this widespread and deep coastal convection is certainly not a given so that will have to be monitored closely.  Also, there is some question as to how far north the warm front will get.  If it stays south of Atlanta, then these major Southeast population center will be spared the worst of the severe weather.   Even though there are some encouraging factors that could lessen the overall severity of this event, it remains a very dangerous one through the day Saturday that everyone needs to pay special attention to and listen for the latest watches and warnings issued for your area.  If the severe weather ingredients available for this system were to come together just right, then it has the potential to be a major severe weather and tornado outbreak on Saturday, so DO NOT let your guard down.  Through Saturday afternoon and evening, the severe threat  sweeps across the remainder of GA, north FL, the Carolinas, and VA.

Meanwhile, back in the middle part of the country a raging late season blizzard is well underway and will continue through Saturday and into Sunday.¬† Thundersnow, snowfall rates of 3 inches per hour, 50 mph winds, zero visibility, 10 to 20 inches of snow, and snow drifts 10 to 20 feet high will create and extremely dangerous condition for those hardest hit across the northern TX panhandle, the OK panhandle and northwest OK, and southwest and central KS.¬† Here is a link to a web cam in the city I spent the first 32 years of my life in, Wichita, KS.¬† http://www.360wichita.com/wichitacam/¬† They have been spared the worst of it so far as some warm air aloft has worked in and created a lot of sleet for Wichita, but coler air aloft will quickly rush in and very heavy snow will fall most of the night and into Saturday morning, piling up to 10 to 16 inches in depth.¬† Tree limbs and power lines are going to come down in the strong winds and snow, and many folks in the region are going to lose power tonight, and it’ll be a few days before crews can get out and fix the problems.¬† Just a terrible situation.¬† My elderly parents live in Wichita, and I’m very worried about them.

My plan is to monitor the weather situation closely from the StormStream Severe Weather Operation Center through the night.  Storm chase and live streaming operations could begin as early as 8am Saturday and continue through much of the day.  I will be streaming at http://www.severestudios.com/livechase/ and http://www.ustream.tv/channel/stormstream-forecast-operations/

Major Outbreak of Severe Storms and Tornadoes acorss Dixie Friday and Saturday. Blizzard in the Plains.

Posted in Severe weather, Winter weather with tags , , , , , , , , , , , , , on March 25, 2009 by stormstream

The next few days will feature WEATHER GONE MAD!  Dangerous and possibly strong to violent tornadoes whipping across the South, while in the colder air Across the central Plains into the Corn Belt there will be a full-blown blizzard.  There is no sugar coating this Рmany lives and property will be impacted and put in danger by weather conditions between now and Sunday.  These types of high-impact, dangerous weather events always leave a sick feeling in the pit of my stomach, because I know there could very well be people going about their daily lives today that will no longer be with us in a few days.  Taken tragically and prematurely by an act of nature than cannot be controlled, but while we cannot control the weather we can certainly talk about it in strong, attention-getting ways that will hopefully make people understand the seriousness of the event, and hopefully spur them to take the necessary steps to protect life and property, thus mitigating losses.

All of the ingredients are there for a high-end severe weather event across AR, LA, MS, AL, TN and western GA during the day Friday and through Friday night.  Northern and central LA, southern AR, southwest TN and western MS appear to be at the greatest risk for all modes of severe weather during the daylight hours on Friday.  the risk will exist for strong to violent long-tracked tornadoes, and I am most concerned about the Mississippi Delta region being ground zero for this potentially deadly weather.

Heading into the darkness of Friday night and early Saturday morning, the greatest threat translates eastward across the remainder of MS, all of AL, western GA and much of TN.  The severe thunderstorm and tornado parameters remain strong, and there is a very real threat for strong to violent nighttime tornadoes across a region that is frequented by these in set-ups like this.  Overall the parameters are generally weaker than those forecast for Friday afternoon, and hopefully that will lessen the severity of the nighttime event, but the potential is certainly there for just a horrible night, especially for eastern MS and much of AL.

On Saturday exact timing and location of the surface features becomes a question, and a precise forecast hinges on the location of these features.  In general, it can be said that severe weather and tornado parameters continue to weaken, but are still high enough for a significant event that would include the possibility of tornadoes.  As the surface low lifts northeast, the unstable airmass in the warm sector will surge north and northeast ahead of it.  This means that there threat for significant severe weather will now extend as far north as the eastern sections of the Ohio Valley.  Under the gun for severe weather on Saturday will be the eastern half of GA, northern FL, SC, NC, eastern TN, central and eastern KY, southern and southeast OH, WV and VA.  At this point I cannot be more specific about Saturday, except to say that the severe weather threat remains significant and potentially dangerous.

While all of this is going on in the South and East, a blizzard will be raging across southwest KS, the OK panhandle and northern TX panhandle during the day on Friday.  Thundersnow will also be a possibility with snowfall rates over 3 inches per hour and howling winds.  This will be a very dangerous storm for anyone traveling across this region, and those caught outdoors unprepared for the extreme winter weather conditions.  The heavy snow and blizzard conditions shift into northern OK and central and eastern KS early Saturday morning, then northeast into the Corn Belt region during the day on Saturday.  The danger factor for travelers and those caught outside unprepared remains high through Saturday.

Looking ahead, another major winter-style storm is possible for parts of the central and northern Plains and western Great Lakes early next week.  The middle and end of next week could again feature a multi-faceted severe weather and winter-weather-producing storm for the eastern half of the country.

Sunday Morning Thoughts on Sunday and Monday Severe Thunderstorm Chances in Kasnas

Posted in Severe weather with tags , , , , , , , , , , , , , on March 22, 2009 by stormstream

No big changes in my thinking.  So far very consistent, which is good.

I won’t beat a dead horse, so all I’ll say about today is if the cap can be breached there could be a classic “no-risk surprise” along the dryline in western Kansas today.¬† If anyone is free and does not have much to do today, then it would probably be worth a stab.¬† You really have nothing to lose except time and a little money.

The speeding up trend for Monday has stopped, and the CAPE is trending ever so slowly upward in recent models.  This is great news.  I think the models have finally landed on a solution.  Initiation looks to be between 3pm and 5pm along a line from Larned to Medicine Lodge.  The storms will then move rapidly northeast at 50mph.  Try to be on the storms early, and be wary of their fast speeds and chase accordingly by attacking them aggressively from a downwind position and not find yourself chasing to catch them from behind.

I still have major concerns about the shallow nature of the moisture.¬† The sounding from Wichita for early tomorrow evening shows the atmosphere drying fairly steadily from just above the surface right on through the atmospheric column.¬† This could make it tough to get robust convection going, at least robust enough to producd the kind of updrafts and downdrafts you need for tornadoes.¬† Still, hail and lightning would be good bets in this kind of dry atmospheric environment.¬† If there is to be a “bust factor” for tomorrow, it will be the shallow nature of the low level moisture.

Also, there may be some showers arond Monday morning and cloudiness may hold pretty tough through a good part of the day.  In these kind of marginal set-ups it is critical that you get good surface heating to help things along.  Keep an eye out on the visible satellite and hope for some good sunshine to get things cooking west of Wichita starting around 11am.  If clouds hold along the dryline through 2pm, then that will not be good.

Zeroing in on Storm Chase Targets for Sunday and Monday

Posted in Severe weather with tags , , , , , , , , , , , , , on March 21, 2009 by stormstream

This blog post will deal mainly with the significant severe weather possibilities on Monday, but I do want to make brief mention of Sunday as well, which in my opinion, is still looking like a chase day for chasers in Kansas.

Moisture will be shallow and meager on Sunday along the dryline with dewpoints in the lower 50s ahead of the dryline in southwest KS.  However, the shear looks good, and the upper levels will be improving through the day.  The EHI values off of the 18z NAM are between 1 and 2 in southwest KS by early evening.  The cap will also be rather strong, but may break by late afternoon or early evening.  A few isolated thunderstorms could pop along the dryline in southwest KS, and they could provide some nice structure, and a landspout cannot be totally ruled out in my opinion.  I seem to be one of only a handful of chasers who is actually interested at all in Sunday, and maybe I will totally bust, but I think there is enough there to at least consider targeting the Meade, KS to Liberal, KS to Tribune, KS, to Dodge City, KS to Meade, KS zone on Sunday.

Monday is going to be the main show for sure.  Positives: Dryline punching in from the west, good jet dynamics, quite favorable shear.  Negatives:  Rather shallow moisture and dewpoints generally between 54 and 59 along the dryline, fast storm motion, and a rather narrow corridor of instability.  However, so far this season we have seen a couple of situations where we have gotten tornadoes out of this type of set-up, so that is certainly a possibility this time as well.  Everything seems to be coming together across eastern sections f southwest KS and all of central and south-central KS.  Of course this zone could change between now and Monday, but right now I feel confident enough to throw out a target of Pratt, KS to Emporia, KS and 50 miles either side of that line.  Development as early as 4pm, but more likely by 6pm.  A few tornadoes possible between 6pm and 10pm.

Interestingly enough parts of KS could be looking at significant snow by late Thursday night and Friday, and a severe weather episode will encompass the Southeast U.S. on Friday and Saturday.¬† I’ll blog about the Plains and Corn Belt snow/blizzard threat, as well as the Southeast severe weather threat on Tuesday once this Plains severe weather threat has ended.

Severe Weather Continuing to Look Likely for the Plains on March 22 and 23

Posted in Severe weather with tags , , , , , , , , , , , , , , on March 20, 2009 by stormstream

Both Sunday and Monday continue to look like possible severe weather and storm chase days in the Plains, and the storm chase team is on stand-by and ready for action.

On both days the major negative factor for severe weather will be the shallow depth and quality of the modified Gulf of Mexico air that will be reside within the warm sector.  We are talking about dewpoints that will mainly be in the 50s and will struggle mightily to reach the lower 60s near the Red River.  This moisture will also be shallow and lead to a good deal of the moisture being mixed out of the lower atmosphere with afternoon sunshine and heating, thus limiting instability.  If there is to be a bust on Sunday, and the potentially bigger day on Monday, then this will likely be the culprit.

Still, there is decent hope for severe thunderstorms, and even a few tornadoes, and that hope resides with good upper level conditions that will overspread the region late Sunday and especially Monday, a sharp and bulging dryline, and more-than-adequate shear for rotating supercell thunderstorms.  These factors alone make Sunday and Monday both days that any respectable storm chaser needs to mark on their calendars as chase days.  This time of year anything you get is a bonus, so why not?

Sunday is an interesting day.¬† I’m sure there will be a good number of storm chasers that decide to stay home on Sunday due to the upper support being well to the west, and the rather meager and shallow moisture.¬† Still, the shear wil be good, and EHI values off the 12z NAM are pushing¬†around 1¬†across northwest Kansas.¬† A subtle disturbance crossing the dryline Sunday afternoon could be the trigger to get storms going along the dryline.¬† If¬†instability were to¬†be just a little stronger than forecast, then a landspout or two might be possible.¬† The cap will also be pretty strong across Northwest Kansas, so any storms that do develop will be discrete with good visibility.¬† To me, this definitely looks like one of those potential “sleeper events” where later Sunday evening there could be a few chasers kicking themselves for at least not taking a stab at it when they had the chance.¬† So, it is definitely something to monitor as we head into Saturday and have better data to analyze the possibility.

On Monday, the upper level conditions improve greatly, but as I stated above, moisture concerns will be present, as will pitential cap concerns.¬† I’d say that anywhere along the dryline from west-central and central KS, southward into western and central OK and northwest and northern TX would be the zone where supercells and a few tornadoes would be possible.¬† I would love for dewpoints to reach into the 60-65 range across the northwest OK and KS portion of the target, and for moisture depth to be greater, but with wind trajectories coming out of the central and western Gulf that has been modified by wintertime arctic airmasses, I just do not see that happening.¬† We really need a fetch out of the Caribbean with these dynamic early season systems to really get them cranking into the major outbreak realm, and that’s not going to happen this go around.¬† Still, given the magnitude of shear and modest instability with a CAPE between 1,000 and¬†1,400 j/kg, and the good upper level environment, severe thunderstorms will be likely with the mode being supercells with a threat for a few tornadoes.¬† The EHI bullseye off of today’s 12z NAM¬†from Medicine Lodge, KS into northwest OK sure looks like a sexy target zone to me at this juncture.¬† However, we are still a couple of days away from this event so this target is sure to change a bit.