Virtual storm chase #1 -- 9-11 March 09

M.T. Cranium · 08-03-2009 10:43pm #1

Virtual storm chase #1
______________________________

Okay, you have joined the boards.ie "virtual storm chase" and here's the situation. You have just landed at DFW and joined the virtual storm chase. It is now Monday, March 9th, 10 a.m. CDT (notice the daylight savings time, it has already begun in North America). I know it's probably not that time yet but this is where the virtual storm chase begins.

CDT is one hour ahead of CST (Central Standard Time) and that's six hours behind Greenwich Mean Time, so CDT is five hours behind. That means it is 1500 GMT or 15z at the moment (play along).

Your virtual tour director has gathered you together at the nearest Dairy Queen for some good old fashioned American ice cream and you're sitting outside enjoying the warm, sultry weather (it is 26 C and the dew point is about 16 C). The discussion begins about what to do next. The guidance is all showing a storm outbreak for late Tuesday in eastern Kansas and western Missouri. The first thing you need to do at home on the virtual storm chase is have an atlas handy, especially if you don't know your U.S. geography all that well. Find Kansas (KS) and Missouri (MO) and notice they are about a day's drive northeast of Dallas.

So you're on the way to Tulsa, Oklahoma (OK) for an overnight stay.

While you're driving, people are checking out latest map guidance and other internet data, either getting a roaming signal near towns on their laptops, or at rest stops outside restaurants with "wi-fi access." This allows you to surf the net briefly while you're in range.

Here are the two main weather websites you will be accessing:

For U.S. data, it's

http://www.nws.noaa.gov

and for additional map and satellite data especially, we use also the Canadian weather site at

http://www.weatheroffice.ec.gc.ca

At this point, as you get your head into this storm chase, I would suggest you check in with the current (late Sunday, Monday) weather pattern over the region, the 24-48 forecast maps available on these sites, and the general situation, which at the moment is this:

Situation for Tuesday storm chase ...

Models are showing a strong cold front developing from about western Iowa (IA) to central Oklahoma (OK) with all signs favourable for tornadic storm development. There is a strong jet stream, high thermal contrast (25 to -10 C across a series of fronts), good moisture feed from the Gulf of Mexico (GOM) and strong wind shear aloft (jet stream is oriented SW-NE but winds rapidly become westerly).

Discussion will take place Monday night as to best position for Tuesday mid-day and afternoon storm chase. Early indications are that Tulsa OK might not be far from "ground zero" in this outbreak so this is why we are heading there first.

Anyway, this discussion will get you started. If you want to take part in the virtual storm chase, bring your own ideas and observations to the thread and together we will "virtually" chase some storms and then report on what actually happened. We'll pretend we are "there" and report as though we are either seeing storms, encountering problems, or chasing off to a new target.

Update some time early Monday local time, mid-day Monday Ireland time.

-- MTC

M.T. Cranium · 09-03-2009 12:58am

Some assistance for you in using the American weather site

http://www.nws.noaa.gov

For national radars, click on "radar" then click on the region of interest. This will direct you to the regional radar. You can animate this by clicking on "loop" and there are also other features besides the standard doppler radar. You'll notice this is a higher grade of radar than is often available on Irish or UK weather radar displays. Of course, with F3 tornadoes whizzing about the place, it has to be.

For latest data, look down the menu on the left sideboard and find "state" click on that, and choose from the menu. This will open up a state menu, the first item shows you the past hour and several recent hours, sometimes venturing outside the state boundaries (each state has a different format, sometimes the first set of obs are too wide-ranging for your interest and you need to scroll down to find the state's weather stations). Most US state weather stations are named for the larger towns, you'll rarely be wondering "where is that?" as with Casement or Finner Camp in my case. Almost all the weather stations are at airports, sometimes these are a good distance outside the city centre. For a storm chase, it is essential to know where the weather stations are located. Note that they are still using Fahrenheit, inches and the like ... you may even need to convert these, one of the few advantages of my extreme age is that I understand these archaic
concepts.

To see recent severe weather reports (and these show up in real time thanks to an extensive co-op network involving county police, emergency managers, citizen volunteers etc) click on "public" and you'll see anything related to severe weather, heavy rainfall, record temps etc.

To get the latest thinking of the NWS regional office, click on "forecast discussion." This will be fairly technical, note that some states have more than one regional office so you need to be aware of which part of the state they are covering. The average American state is about the size of Ireland or even the UK; the larger ones are about the size of France or Germany.

Returning to the main website, the latest map is a bit hard to find, click on "maps" but go to the bottom of the display and click on the small blue item that reads "hi-res map" which should open up a large-scale plot of recent weather updated at 3h intervals (about 2h into the 3h periods).

I recommend the Canadian site for all other map usage including upper air.

Let's orient to that now ...

http://www.weatheroffice.ec.gc.ca

You may need to click on "English" to get a menu as Canada is a bilingual country (English and French). Or do it in French if you want, same maps.

Then click on "maps and analyses" in the menu, find the latest surface maps that update every 6h about one hour into the cycle (left) or for a more global view, more like four hours into the cycle (right).

For the standard upper air maps, click on the four choices, 250 mbs, 500 mbs, 700 mbs, 850 mbs. You'll get whatever map is current. The 00z maps appear after 0230z and the 12z maps after 1430z.

Some time after that, the regional GEM panels update on "regional" ... this brings up the latest GEM detailed prog maps for 12, 24, 36 and 48h. The longer range show up on "global" and start to update about 3-4 hours into the cycle.

The RGEM maps are usually excellent for severe weather because they tend to have their smallest errors near tornado alley (the Canadian GEM model is generated from a starting point over central N America). Unlike its utility in western Europe, the GEM can be compared to the ECM and GFS favourably for North American forecasting; it tends to have a slight warm bias at times.

I'll use these maps in the virtual storm chase starting with the 12z Monday charts as if we were discussing them on site at Monday brunch time.

I hope anyone having problems following the path to this guidance will speak up early on, so we can resolve "how do I see?" questions before we are virtually staring down a supercell thunderstorm.

-- MTC:cool:

maquiladora · 09-03-2009 11:47am

Great idea for a thread MTC, excellent work again as always.

I've often heard in storm chasing docs NOAA weather radio's calling out tornado warnings during chases. Do you know if there is a live web stream for this service too?

forkassed · 09-03-2009 1:01pm

This should be fun!

Heres some sites that hopefully will come in handy

Storm2k

Apparently this one offers live streaming of storm chases but im not sure whether its free or not..

http://www.tornadovideos.net/

http://tornadovideos.net/full-screen-chaser-video.php

maquiladora · 09-03-2009 5:15pm

Another site which seems to host live chase streams - http://www.severestudios.com/livechase

M.T. Cranium · 09-03-2009 5:21pm

Not sure about the access to the radio warnings, will research that.

In any case, we are now in "real time" on the virtual storm chase at 16z or 1100 CDT. From the morning (12z) runs we have noted that the severe storm potential is probably going to be greatest from central IL to south-central MO to nw AR. This is generally a half-day drive beyond our overnight stop in Tulsa OK but as the severe weather will develop from around there and move east, we figure that we should be in position as long as we get an early start.

And people are tired from their trip, jet-lag is not a huge factor going west because you stay in the same time zone then have a late end to your biological clock day, rather than the more disruptive short night and early start of an eastbound jet-lag. So we want to have a reasonably early supper break and not be awake past midnight as will often be the case during the excitement of a storm chase.

The 36h prog for 00z Wednesday shows the situation expected for 7 pm Tuesday ...

http://www.weatheroffice.gc.ca/data/model_forecast/593_100.gif

At the present time, the warm sector of the storm is just beginning to pull together warm, moist air from the GOM. It's generally around 22 C as we're driving north from DFW towards Ardmore OK and the trip to Tulsa. We'll be passing through Oklahoma City (OKC) around 2 pm after a short lunch stop, then we should make it to our motel in Tulsa by about 5:30 or 6 pm. The guidance suggests that some showers or brief thundershowers could begin to pop in this warm air mass by then, and we're expecting some overnight thunderstorm activity as the stronger frontal zone begins to develop.

In the height of the severe storm season, outbreaks like this will feature two active zones, one along a "dry line" front that comes out of west Texas ahead of the hot, dry desert air mass, but ahead of the dynamic cold front that separates the hot air from advancing cooler air from a Pacific origin. By late May or early June, the arctic front is usually a weaker feature that may be absent from the central plains weather systems altogether, or else may be hanging back as a weak secondary front. But in March and April, the arctic front is usually quite strong, as snow cover and very cold conditions remain in place as far south as Montana and the Dakotas on occasion.

So with this system that's developing, the cold fronts will be very strong and there may be almost no dry line feature, it will be more of an upper-level trough or windshift ahead of the main cold front, but even so, severe weather that's easy to isolate and chase often develops out ahead of the main bands of squall line thunderstorms, so we're going to be keeping a close eye on this advance feature tomorrow morning to make sure we're not caught behind the best severe storms and in the "grungefest" as many like to call the larger continuous zones of heavy to severe storms.

Visibility is everything in the storm chase, if you can't see it, you're going to experience it in some way that is not so easy to record. This may still be "worth it" but obviously, you've paid to see and to record evidence of severe storms.

Another resource we will use is the daily severe storm outlook issued from the Severe Storm Prediction Centre (SSPC) in Norman, Oklahoma (south of OKC). Our trip today, if it were higher-end in terms of cost and organization, might well include a visit to the SSPC, and an on-board "Baron" radar system that has the radio warnings and other features mentioned.

Other storm chasers on more of a budget rely on fixed internet stops and then navigate from their theory of how the outbreak will develop, using whatever access to data and warnings they can manage in real time. The two methods tend to converge on the same cells in practice. However, on some severe weather days, you're presented with two or three potential outbreaks perhaps 200-400 miles apart and you have to choose well in advance which of these you might be chasing.

Last May, for example, many storm chasers passed on the F4 storm that developed in northeast OK and southwest MO, and were chasing various F2 to F3 cells in s.e. OK and central AR. The cells further north might have been more dramatic for video but were so large and fast-moving as to be positively dangerous for anyone within a mile or two of their track. We have the option of driving through that damage zone after breakfast on Tuesday (the worst of the damage occurred right where OK, KS and MO meet; a small town that was in any case being closed down due to fears of toxic waste from an old open pit mine was pretty much levelled, and the severe damage extended through rural and small-town portions of southwest MO for perhaps 15-25 miles).

So to get back to the here and now, we are just getting to the bridge across the Red River (Lake Texahoma in this stretch thanks to a dam) and leaving Texas for Oklahoma. It continues to be mostly cloudy, rather warm with a southerly wind at 10-15 mph. The low is just now getting its act together in Colorado, and somebody notes that it is -25 C in Calgary, about as cold as it gets there at this late stage of winter.

We'll resume the narrative with a discussion "this evening" around 03-04z that should be there for you in the morning. We're expecting the active storms to peak around 21z on Tuesday, so the actual "chase" part of the day will come around 7-10 pm your time, or 2-5 pm CDT.

-- MTC

M.T. Cranium · 09-03-2009 5:29pm

1630z (update)

We are hearing on the radio that the region we are driving through is now in a slight risk for severe storms later TODAY. So we may be chasing before sunset if any large storms develop in northeast OK. This has us looking for large towns along the interstate highway between OKC and TUL, because we may wish to stop in at a restaurant with internet access, grab a coffee and fire up the radar. We have reservations in Tulsa so we aren't bound to an arrival time there, if we have to go off-route to follow a storm. We're speculating from the guidance that if anything does develop to severe limits, it might be around Stillwater to Ponca City, north of the highway and up towards the Kansas border. This is good chase country, fairly flat although rolling with deep valleys carved out by the rivers, and mostly treeless, ranching country just getting into the first of the "corn belt" that dominates eastern KS. Highways are generally straight-line and not particularly busy even in late afternoon, so if we have to chase today, this will be a good place.

Therefore we may have a report around 20z today, at least one to say no storms have popped yet. We're pretty sure there will be some activity, the question is whether at this early stage it becomes severe.

-- MTC

M.T. Cranium · 09-03-2009 5:50pm

This is the radar loop, it has disappeared from the post above (perhaps a mod is fixing my post?) ... this radar loop will probably update so I won't describe it "now" ... you'll have to check it and see what it's showing.

http://radar.weather.gov/radar.php?rid=vnx&product=N0R&overlay=11101111&loop=no

I think we'll now pretend to drop in at the SSPC and grab a Baron system. Then I won't have to pretend we can always find that restaurant with the internet access every time we need a radar fix.

So here we are (I think we've been driving at 120 mph but this is fairly normal for storm chasers).

And here we go, there are a few blue patches showing in the low stratus overcast, but nothing to give us any visual fix on "towers" building off to our west (about 50-100 miles away). We're hoping for more broken skies later this afternoon once we get to around Stillwater, northeast of OKC.

Okay then, in real life I am now out for several hours ... we'll resume the storm chase in real time around 20z and see if anything did develop today after all. Think it might from the looks of the radar (currently shows moderate cells about 70 miles WNW of OKC, direction northeast at about 30 knots).

forkassed · 09-03-2009 5:56pm

M.T. Cranium · 09-03-2009 9:19pm

2015z March 9 09

We're now sitting at a gas station and convenience store complex outside Stillwater OK. It's mostly sunny now, quite warm and a bit on the humid side
(25/16). This is where our pasty white legs start to sunburn (don't forget, we're at the same latitude as Morocco here). As the radar posted by FA shows, cells have moved into southern KS but this activity is well below severe limits along the developing warm front. The low is about 300 miles to our northwest in eastern Colorado, and there is a weak dry line feature looping southeast then southwest from this low, for example in the Texas panhandle at Amarillo with similar temperatures to here, the dew points are close to 1 C, and the wind is strong from the SW.

This dry line begins to fade out over west Texas and the radar is showing some activity over the normally dry region south of El Paso in Mexico. This is probably the first signs of the developing severe weather event for tomorrow.

We figure at this point there is perhaps a 10% chance of anything active popping up in north central OK this evening, probably the action developing over west TX will remain rather subdued overnight and begin to develop more rapidly around sunrise when it's north-south through central OK and eastern TX.

We're probably going to head off soon to Tulsa and await the 00z guidance for some decisions about where to head in the morning. It seems possible we will be driving east for some time, checking our on-board radar for developments behind us, and stopping in a good location, then trying to keep up to any large cells that may develop as far east as southern Illinois.

If you're following this, you can also use google earth as a resource and see what kind of terrain we will be crossing. Southern Missouri and northern Arkansas are hilly, the Ozark "mountains" which are more like big hills, are largely wooded and so not the best terrain for a storm chase. Also the climatology of tornadoes shows a bit of a split around this area, more to the north and south in central MO and south to central AR. One notorious path for tornadoes seems to be Little Rock AR to around Jonesboro AR and across the Missouri "bootheel" (the southeast corner) into w Kentucky or far southern IL. We suspect this is the path that might become prime storm chase territory on Tuesday. But some might opt to stay back in southeast OK or even ne TX where the trailing edge of the complex might generate better viewing if less severe storms.

So we'll resume if anything pops up now to 00z (7 pm CDT) otherwise, the action should become more interesting tomorrow with the first post being around 0500 discussing the 00z guidance.

-- MTC

M.T. Cranium · 10-03-2009 6:40am

0530z Tuesday March 10th, 2009
_______________________________

It is now 1230 a.m. CDT and we've had chance to assess the latest info in the model runs, the developing frontal situation, and basically nothing much has changed from the earlier guidance.

From about 02 to 04z a cold front made some eastward progress around a line from Wichita KS to OKC, with some thunderstorm development. This feature is still off to the north and west of our overnight location at Tulsa OK.

We expect it to weaken but move to or slightly past our location before 12-15z as we wake up here, have breakfast and set out. The plan we've chosen is to move about halfway through Missouri, taking I-44 from Tulsa to Springfield, about a 2-hour drive at most, then US 60, a 2-lane highway, due east through rolling country in southern MO to about Willow Springs. Here we should be able to get a fix on the developing severe storms that we expect to be to our north and west, and decide whether to stay put, edge further east, or find a route north. We figure the eventual best storm chase set-up will be in southeast Missouri perhaps around Poplar Bluff.

We've checked routes and found there are two bridges across the Mississippi River, one being I-57, another four-lane highway that runs north from Cape Girardeau (CGI) towards Carbondale, a large town in southern IL. Another bridge option is further north about halfway to St Louis. We want to avoid chasing storms anywhere near St. Louis if possible due to traffic congestion in this large city. The town of De Soto is about as far north as we would likely want to travel.

There may well be tornadoes in this complex of severe storms. The SSPC guidance will come out in the morning, but regional offices are agreeing with our in-house assessment of at least a slight risk in eastern MO, western IL, far west KY-TN and far northeast AR. The situation looks active but perhaps one notch below what you might call explosive. The storm actually gains further strength overnight into Wednesday morning, but by then storms will be well to the northeast around IL-IN, OH and even s MI.

So, this is the plan for Tuesday. We have an early wake-up at 0600 local (11z) and a quick check of the latest guidance, then we'll start to roll unless the later info suggests a different plan.

As you read this, remember, the time zone is five hours behind (factoring in the daylight savings) and so when it gets to be noon in Ireland, it will be 0700 CDT and we should be eating breakfast (virtually, of course).

Having a cold one now, it's still quite warm outside (in Tulsa, that is, it's damn freezing where I actually am) ... 22 C and southerly wind at the last hourly obs.

Next post around 14z.

-- MTC

maquiladora · 10-03-2009 1:12pm

Forecast Discussion

SPC AC 100600

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE MAR 10 2009

VALID 101200Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ARKLATEX REGION NEWD
INTO THE SRN UPPER GREAT LAKES...

...SYNOPSIS...
STRONG MID-LEVEL SHORT-WAVE TROUGH CROSSING THE ROCKIES AT THE START
OF THE PERIOD -- WITHIN THE LARGER-SCALE TROUGH OVER THE WRN HALF OF
NOAM -- IS FORECAST TO TAKE ON AN INCREASINGLY-NEGATIVE TILT AS IT
LIFTS NEWD ACROSS THE PLAINS THROUGH THE DAY. THIS FEATURE WILL
THEN CONTINUE SHIFTING RAPIDLY NEWD ACROSS THE UPPER GREAT LAKES --
AND ON INTO ONTARIO BY THE END OF THE PERIOD. ELSEWHERE...WEAKER
TROUGHING WILL REMAIN OVER THE WRN CONUS IN THE WAKE OF THIS
FEATURE...WHILE THE ERN U.S. RIDGE GETS SUPPRESSED/SHUNTED EWD WITH
TIME.

AT THE SURFACE...A WEAK LOW IS FORECAST OVER MO AT THE START OF THE
PERIOD...WITH A TRAILING COLD FRONT MOVING SWD ACROSS THE CENTRAL
PLAINS/SRN HIGH PLAINS. AS THIS LOW MOVES NEWD THROUGH THE DAY
TOWARD WI....THE TRAILING FRONT WILL CONTINUE SWD...WHILE A WARM
FRONT MOVES NWD ACROSS THE MID MS VALLEY/MIDWEST REGION. BY LATE
AFTERNOON...THE APPROACH OF THE SHORT-WAVE TROUGH SHOULD CONTRIBUTE
TO SUBSTANTIAL SURFACE CYCLOGENESIS...WITH A RAPIDLY-DEEPENING LOW
EXPECTED TO CROSS THE UPPER GREAT LAKES THROUGH THE END OF THE
PERIOD. AS THIS OCCURS...THE TRAILING COLD FRONT WILL BEGIN SURGING
MORE QUICKLY EWD ACROSS THE MIDWEST/OH VALLEY...AND SEWD ACROSS THE
S CENTRAL CONUS THROUGH THE PERIOD.

...ARKLATEX NEWD INTO THE UPPER GREAT LAKES REGION...
SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS ARE FORECAST TO BE
ONGOING AT THE START OF THE PERIOD...FROM PARTS OF THE MID MS VALLEY
REGION SWWD ACROSS THE OZARKS/SERN OK AND INTO TX. WHILE MODEST
BOUNDARY-LAYER MOISTURE WILL BE ADVECTING NWD WITH TIME ACROSS MO
TOWARD THE MID MS AND LOWER OH VALLEYS...DEGREE OF
MOISTURE/INSTABILITY SHOULD AGAIN PROVE TO BE A LIMITING FACTOR WITH
RESPECT TO THE DEGREE OF SEVERE POTENTIAL THIS PERIOD.

THIS LACK OF INSTABILITY -- PARTICULARLY WITH NWD EXTENT -- WILL BE
AT LEAST PARTIALLY OFFSET BY THE INTENSIFYING SURFACE SYSTEM AND
ASSOCIATED UVV...AND BY A VERY STRONG DEEP-LAYER WIND FIELD
/INCLUDING 80 TO 100 KT SWLY FLOW AT MID LEVELS/. ATTM...IT APPEARS
THAT THE GREATEST JUXTAPOSITION OF FAVORABLE INSTABILITY AND SHEAR
WILL EVOLVE FROM ROUGHLY CENTRAL IL SWWD ACROSS MO AND AR TO THE
ARKLATEX REGION. WHILE THE GREATEST POTENTIAL FOR A TORNADO OR TWO
APPEARS TO EXIST ACROSS PARTS OF ERN MO AND IL DURING THE AFTERNOON
-- NEAR THE LEADING EDGE OF RETURNING MOISTURE -- THE THREAT FOR
DAMAGING WINDS AND HAIL SHOULD INCREASE THROUGH THE AFTERNOON AND
INTO THE EVENING AS THE COLD FRONT SHARPENS AND FORCES A MORE
ORGANIZED LINE OF STORMS. THE THREAT FOR WIND DAMAGE WITH A FORCED
LINE OF CONVECTION MAY SPREAD ACROSS PARTS OF NRN IL/IN AND PERHAPS
EVEN INTO LOWER MI LATE IN THE PERIOD...BUT VERY MEAGER INSTABILITY
SHOULD GENERALLY LIMIT THE NWD EXTENT OF THE THREAT DESPITE VERY
STRONG FORCING CROSSING THE UPPER GREAT LAKES REGION.

THE THREAT SHOULD BEGIN TO DIMINISH THROUGH LATE EVENING/OVERNIGHT
AS THE FRONT SURGES EWD ACROSS THE MIDWEST/OH VALLEY AREA...THOUGH
SOME THREAT MAY LINGER ACROSS E TX/THE ARKLATEX REGION THROUGH THE
END OF THE PERIOD AS FRONT CONTINUES SEWD THROUGH
MARGINALLY-UNSTABLE/AMPLY-SHEARED ENVIRONMENT.

..GOSS/HURLBUT.. 03/10/2009

M.T. Cranium · 10-03-2009 7:12pm

18z (1 pm CDT) Tuesday, March 10th
____________________________________

Okay, here's a log of our morning activities (I had an early look then had to go out, but things are on track) ...

We all got up eagerly to have a look at the 12z data and have some breakfast. First thing we got was the SSPC outlook as posted above by Maq.

As it was 13z (0800 CDT) the models were not out yet but we could see from the data that things were on track from the overnight models and the evening frontal activity had died out as expected, the remnants now being spread out along a warm frontal wave well to our northeast. The cold front was now closing in on Tulsa and hanging back to the southwest.

We decided to drive to Springfield MO on the I-44 (a four to six lane interstate highway). At one point we were a few minutes away from Picher, the small town in the northeast corner of OK that was devastated by an F4 tornado last year in May. But our schedule didn't allow us to take a detour, besides, the town might be barricaded because they were already in the process of closing it down, the whole place is built around the remnants of nasty open pit mine scars and the tornado was more or less the last straw.

So now we are just pulling into a rest stop near Springfield, Missouri. Our two choices from here are to continue at whatever pace on I-44 further northeast, or to head off due east on US 60, a generally two-lane highway with some four-lane sections. That would take us through rolling country near the Ozarks, and eventually lead to southeast Missouri around Poplar Bluffs.

Our onboard radar shows the cold front slowly re-activating off to our north and west, nothing imminent in terms of severe weather.

The 12z models have come in while we were driving, and they really look identical to last nights' maps ... by 00z (which will be 7 pm local time) the front should be around northwest IL and draped through eastern MO, to northwest AR. The slow movement of the front, the best upper support lying through central MO, and the rapid intensification from 00z to 12z shown on the models, all conspire with the look of the current obs and radar to suggest that most of the action will be just ahead of this front and not well out in advance of it ... so we shouldn't move too far ahead of the front. At the same time, it is easier to chase from in front than from behind severe storms because you want to avoid driving through the associated rainfall and poor visibility behind the cells.

We're thinking, then, that the best staging area may be a little further north than our hunch from last night, so we make the decision to stay on I-44. We are probably too far west to stay put even though it is still 22 C with a sultry SW wind here. The upper level maps have a tight 500-mb wind shear zone (curved flow from SW to W) that is the usual producer of severe storms, located near Columbia MO we estimate at 21z, so we are going to keep driving northeast as far as Rolla, MO (in the centre of the state) and take another decision around 20z (3 pm CDT).

In the meantime, here's the radar screen that should become active between now and then, the cells are currently a little off to the west of this screen but you'll see Springfield, Rolla and Columbia on the screen, and I'll return some time after 20z with an update ...

http://radar.weather.gov/radar.php?rid=lsx&product=N0R&overlay=11101111&loop=no

M.T. Cranium · 10-03-2009 9:37pm

2030z (3:30 pm CDT)

UPDATE ...

Our onboard "Baron" radar is showing gradual development of the front to our west as we now sit at a truck stop near Rolla MO off I-44. We note that there is a certain amount of "grunge" developing ahead of the more active part of the front, and in more general terms, it is still relatively clear off to our south and southeast, cloudy to our east and northeast in the warm air mass. The temperature here is 24 C with a dewpoint of 14 C. Winds are SSW at about 15-25 mph.

About 100 miles northwest of here it is closer to freezing with a strong W wind. But this system is just beginning to develop now. We continue to think it will go heavy and then severe in the next 2-4 hours. We have four hours of daylight left.

Currently then, we will head another 30 miles eastnortheast to Cuba MO, where a road junction (State 19) will provide the option of heading due north, and other roads ahead will allow an east to east-south-east chase. It all depends on how the cells develop now. Update to follow at 2100z. See the previous post radar to see the general situation.

Would recommend if you're following along, get a window open on "MSN map" or "google map" centered on Rolla MO and at a scale where you can see about 50 to 100 miles of geography. You'll see the roads I am talking about. You could use google earth and have the landscape too, but basically this is fairly open rolling farmland with some wooded areas here and there, it's not dead flat, and there is one area of higher hills off to our southeast (Taum Sauk Mtn at about 1800 ft asl is the highest point in Missouri, down here we are at about 300 ft asl.)

Back at 2100z or thereabouts, near Cuba MO.

M.T. Cranium · 10-03-2009 10:13pm

2115z UPDATE

Now sitting near Cuba MO on Missouri State Highway 19, just north of I-44. From here we can go due north to intercept the front in 1-2 hours, or we can go south for ten miles then east on MO state highway 8 if it appears that the best cells are going to develop to our south.

Radar is not decisive yet, we have continued gradual development off to our west. Occasional sprinkles of rain now as some pre-frontal showers move through, it is still warm and humid (23/15) with a south wind.

Updates as events unfold.

We have three hours of daylight left.

M.T. Cranium · 10-03-2009 10:34pm

2130z (4:30 pm CDT)

Have decided to head 12 miles south to Steelville, almost there now, from here we have options of heading further south or east on State Highway 8.

Reason for this move, front appears to be q.s. now and we are in intermittent light rain with reports from further WSW along the front indicating convection is firing a bit south of our relative position (near the nw AR sw MO border moving ENE). We figure to get in position to catch the developing cells somewhere 15-30 miles south but possibly needing to go east to stay with them after 2230z.

As I typed this, have arrived in Steelville MO, breaks in overcast to south, light rain has now ended, quite sultry feel 23 C dp 15 C. Sky dark grey to our west and getting blackish to our northwest.

Updates as necessary.

forkassed · 10-03-2009 10:42pm

I'l just throw this radar in to save switching back and forth- i'l update it every 1/2 hour or so and go lookin for any live streams from the area

.......................

Heres links to 2 live streams

Stream 1

Stream 2

M.T. Cranium · 10-03-2009 11:48pm

2245z (5:45 pm CDT)

Have been driving slowly south on State 19 from Steelville since 5 pm, now about 15 miles south of there and looking for a good spot to get video as we expect heavy cells possibly severe soon to be crossing this highway in about 30 mins. Approx 90 mins of daylight left. Looking black off to our west. Highway is winding through areas of woodland and cleared fields, visibility will become an issue soon.

Best presenting cells on radar are still off to our southwest, but no reports of severe weather anywhere along the front IL, MO or AR yet. Seems like activity is increasing since 2215z though.

Update to follow.

maquiladora · 11-03-2009 12:30am

Thanks for the updates MTC...

Looks like we are not alone in "chasing" this today, there is live streaming video from Brian Emfinger here, dashboard cam, pretty good quality : http://tornadovideos.net/full-screen-chaser-video.php

Adds to the feeling of being there a little.

M.T. Cranium · 11-03-2009 12:33am

2330z (6:30 pm CDT)

Sitting beside Highway 19 at Cherryville, a small hamlet southeast corner of Crawford County. From here the highway turns southwest and heads through rolling and somewhat more wooded country to Salem, MO. Considered heading that way but cells are speeding up and the view here is unobstructed. Worried that further west we will run into the developing squall line without a good viewpoint and get into a severe storm with large trees to our west. Not a good concept. Here (you can check on google earth) we have open farmland to our west. We're just north of the highway junction of 19 and 49.

A few spatters of rain came and went five to ten minutes ago, those are now off to our east, and we have a clear slot overhead. To the west it is quite black. (I am now assuming a few things) Have seen one or two brief flickers of lightning in the advancing cells.

If you look at the radar screen FA posted above, we are near the 2 o'clock position on it, just about at the edge. You can see the front advancing rapidly towards us. Sunset is about 45 minutes from now. We are going to drive through the small village and check for a safe parking spot east of some sturdy building in case we get strong gusts or hail.

The way this has developed, there is no one obvious cell with tornadic potential, it's likely to develop rapidly now into a squall line with severe characteristics from central IL to north central AR. We're pretty much in the best place we could be, I think (or the worst if that's your perspective).

Hope we don't get hail dents.

No severe weather warnings yet.

Update soon.

M.T. Cranium · 11-03-2009 12:35am

2337z

Incoming, bow echo on radar now 30 miles WSW of our location, closing fast.

Black as night to our west. (It is still 22 C and sultry outside, wind picking up SSW 20-30 mph).

M.T. Cranium · 11-03-2009 1:28am

0020z (7:20 pm CDT)

Squall line moving through now, we got some good views of the structure as it approached, just a few CC lightning bolts, nothing too scary, and winds picked up to SW 40 mph in gusts. We are parked on the east side of a service station but the wind is not too severe. Bursts of moderate rain and the sky to our west is lightening with some higher clouds catching the setting sun, so overhead and southeast to east rather black, west grey with white and blue patches, some yellow and orange highlights.

Rain now easing off. Almost dark but could briefly see the setting sun on western horizon, more CBs to the far west (light activity on secondary front).

0025z Rainbow noted to our east against dark clouds. Rain ended.

Now heading south to Salem and West Plains MO for overnight stay.

May make a few more comments, but basically this storm chase would probably return to southern AR or northeast TX tomorrow, however, as this is a test case we won't be reporting on further action because there would now be several days wait for the next event. In the main season, there would likely not be such a long pause between events, but if there were the weather would likely be warm to hot.

Expecting the weather here to chill down to about 2-4 C overnight and so we will want to get moving in the morning to return to warmer zones further south. Could turn to freezing rain or snow where we are now (but we won't stick around for that).

Overall, a fairly successful day in terms of positioning and getting a good view, will have to monitor real-world reports on the storm to see if any reports come in from around our virtual location, but from radar I don't think there would have been severe impacts, it was a brief heavy downpour with some lightning basically.

Expecting some tornadic development through the overnight hours, mostly to our east in IL, IN and OH. Can't chase storms in the dark though.

Thanks for your additions to the thread. One thing to keep in mind, sometimes radar loses full intensity of your chase storm if the beam is coming from point A to your location through point B in another heavy cell. So we always have to be careful to interpret large-scale radar with this in mind (the shadow effect of strong cells).

-- MTC

TheGreenGiant · 11-03-2009 1:14pm

This is class stuff guys!! Really interesting. You should check out tornado videos channel on You Tube as they have up to date videos of storm chasing on whats happening over there.:)

forkassed · 11-03-2009 2:28pm

It was more interesting than i expected it to be, Cheers for the effort you put in M.T.C,

I also improved my american geography quite a bit.

A question remains though..

If i land in texas or wherever and rent a car out for 2 weeks and it gets destroyed with tennis ball sized hail, is it covered by insurance?

M.T. Cranium · 11-03-2009 5:43pm

No, but it will be covered by hail dents.

Sorry, that was rather lame. The real answer is, I don't know, but I know somebody who does (on NW) and I'll ask him, because this happened to him last year, somewhat less than covered by hail dents but there were one or two for sure. I have heard of other people sustaining a lot of damage to storm chase vehicles but not sure if they were renting. I would drive my own vehicle as I did on the small-scale storm chase in August 2007. It would cost me less to drive from here to Colorado than to fly, let alone fly and rent a vehicle.

Yeah, that was an interesting exercise and I'm pleased with the outcome from a thought-experiment point of view, the weather never quite boiled over yesterday but we did get to about the most prime location that the system offered, so that's the point of the whole thing.

I will wait several weeks and perhaps do one more virtual storm chase if there's a big outbreak looming later in the spring.

See what I can find out about the hail question. I would imagine these rental people would prefer not to rent to storm chasers but it must be pretty obvious in some cases, I mean, why else would four guys show up from Britain in May wanting three weeks of unlimited rental? Especially if some of them are the same guys who brought back a slightly dented vehicle a year ago? On the other hand, lots of people in that part of the world sustain hail damage to their vehicles, so the rental companies must be used to dealing with it. Perhaps "hail damage" is one optional insurance coverage you can buy then whatever happens you're off the hook. It wouldn't be as bad as sliding into a muddy ditch at 40 mph which happened to one storm chaser a few years ago. Moral of the story, try not to chase on dirt roads.

maquiladora · 19-03-2009 12:52pm

We could have another virtual chase on the cards pretty soon....

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0358 AM CDT THU MAR 19 2009

VALID 221200Z - 271200Z

...DISCUSSION...
A SEVERE EVENT REMAINS APPARENT FOR MON. MAR. 23 /DAY 5/...WITH
MEDIUM-RANGE MODELS CONTINUING TO FORECAST A MID-LEVEL LOW SHIFTING
EWD OUT OF THE ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS THROUGH
THE AFTERNOON. WITH A FAIRLY BROAD/RELATIVELY MOIST BOUNDARY LAYER
FORECAST TO BE IN PLACE AHEAD OF A SURFACE CYCLONE LIKELY CENTERED
OVER THE CENTRAL HIGH PLAINS DURING THE AFTERNOON...SETUP APPEARS TO
FAVOR WIDESPREAD THUNDERSTORM DEVELOPMENT.

WHILE SOMEWHAT MERIDIONAL -- PARTICULARLY OVER THE CENTRAL
PLAINS...WIND FIELD WILL BE PLENTY STRONG TO SUPPORT
SEVERE/SUPERCELL STORMS -- AND THUS ATTM IT CONTINUES TO APPEAR THAT
A FAIRLY WIDESPREAD SEVERE EVENT IS LIKELY.

BEYOND DAY 5 -- AND PARTICULARLY BEYOND DAY 6...MODELS BEGIN TO
DIVERGE IN POSITION OF THE MAIN FEATURES...WHICH CASTS UNCERTAINTY
INTO THE SEVERE FORECAST. HOWEVER...EVEN GIVEN MODEL
DIFFERENCES...IT APPEARS ATTM THAT THE PRIMARY SEVERE THREAT WOULD
OCCUR DAY 5...WITH DECREASING POTENTIAL FARTHER E INTO THE MID MO
VALLEY REGION FOR DAY 6.

..GOSS.. 03/19/2009

M.T. Cranium · 19-03-2009 10:06pm

I was looking at that situation too, I may post something on Friday evening for the weekend into early next week. This looks a little more powerful than the last event which was interesting but hardly violent in nature. I think you've had stronger storms in Ireland this year already.

Virtual storm chase #1 -- 9-11 March 09

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