Saturday, June 19, 2010
More Storms Tonight
Friday, June 18, 2010
Tornadic Thunderstorms Up North
One last thing- the NWS, sensing the potential tornado threat, included this message in its latest warning text:
THIS IS A SUPERCELL THUNDERSTORM. DUE TO THE ROTATING NATURE OF THESE
STORMS...THEY ARE CAPABLE OF PRODUCING ALL TYPES OF SEVERE WEATHER...
INCLUDING EXTREMELY LARGE HAIL...DESTRUCTIVE STRAIGHT LINE WINDS AND
POSSIBLY TORNADOES. MOVE QUICKLY TO A SAFE SHELTER...PREFERABLY INTO
AN INTERIOR ROOM...SUCH AS A BATHROOM OR A CLOSET...OR INTO A
BASEMENT.
Sunday, June 13, 2010
Severe Thunderstoms Moving Into KC
Saturday, June 12, 2010
Flash Flooding is Likely Today
- Never drive through flooded roadways unless it is an absolute must, and even then, only if the water is not flowing or is flowing slowly and is less than 6" in depth. If you cannot tell how high the water is, do not cross in any circumstances.
- Flooding is likely in any low lying areas. Make sure that pets, lawn furniture, balls, etc. are on higher land this evening. Water that isn't even up to the top of the grass can sweep many things away.
- Floods may reach your house. If so, do not exit unless critical for your safety, remove the power source from any exterior electronics and electrical plugs, and put sandbags around your doors if possible.
Also this evening is a slight risk of severe weather. Any thunderstorms that become particularly strong will have a risk of producing some isolated damaging winds and marginally severe hail. Shear and helicity are very low today for this area, so the chance of any tornadoes is close to none. But, we can't rule out the possibility of a weak tornado along the front. The map below shows the cold front, low pressure centers, and severe weather risks.
So tonight, the main risk, and very deadly risk, is flash flooding. There is a limited threat for severe weather, and a near-zero risk for tornadoes. If anything changes, I'll post again later, but for now, enjoy the last couple of hours of warm temperatures, clear skies, and dryer air! I will mention that the dewpoints are climbing toward 75, so it is beginning to get humid. Have a nice evening!
Tuesday, June 8, 2010
Tornado Watch
Severe thunderstorm warnings are now being issued across the tornado watch. Here's a radar image from 4:40 of the supercell south of KC near Spring Hill. This thunderstorm can produce 70MPH winds and baseball sized hail. Some rotation has been observed, so pay close eye to all future warnings. Keep a weather radio close by tonight!
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Most of the area is now under Tornado Watch #285 effective until 9PM tonight. The counties in the watch are highlighted in yellow in the image below.
Conditions are favorable for, possibly, our biggest severe weather event of the year. Isolated tornadoes, very large hail, and wind gusts are likely with the thunderstorms that, as of right now, are rapidly developing and intensifying. None of the thunderstorms are severe right now, but are dropping torrential rains with 1" per hour rainfall rates. Flash flooding is a major concern, especially in northern Missouri. Remember, do not cross roadways that are covered by water. 6" of water can sweep a car away. I'll update in a few minutes.
Severe Thunderstorm Watch
Alright, this is just a quick update that the storms are making there way into the KC area, and they have weakened below severe limits. Lots of lighting, heavy rain, a wind gust or too, and maybe some pea sized hail in some places is possible with these thunderstorms. I'll update in a few hours on tonight's severe potential.
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The SPC has issued Severe Thunderstorm Watch 284 effective immediately and expiring at 9AM CDT for portions of the KC area, from the 2nd tier of counties in eastern KS to points westward into central KS. A map with the watch regions highlighted is below. You can also see the radar picking up the leading edge of a bow-echo in north central KS and southern NE. These storms are very strong, packing winds up to 70MPH, and some gusts may be even higher.
If this bow echo holds together and retains the strong winds, it should pull through KC around 8AM this morning with the possibility for severe winds. I have relatively high confidence in the timing of these thunderstorms that are associated with an MCS, or mesoscale convective system, which is simply a large mass of thunderstorms all behaving in a similar fashion, and moving in a similar direction.
As for the rest of tomorrow, below is my revised version of the SPC Day 1 outlook. I believe that tomorrow afternoon, more severe thunderstorms will develop along or just north of I-70, and that they'll push southward with large hail, damaging wind, and possibly a couple of isolated tornadoes.I'm not sure how readable my text is there, so sorry for that. But, what it contains is reference to my forecast that the highest tornado threat will be confined to along and just south of the front, which may set up anywhere from north central MO to just south of KC. Right now, my best guess and the best guess of the NWS using the NAM model is that the front will set up along I-70 and stretch northeast into IL.
For tonight's storms, around 8AM you can expect some thunder around, severe weather possible so keep a weather radio on if you won't be up by then. I think that the storms may weaken, but we'll just have to see. Have a great night everyone! And, I'll update before 8AM if the storms continue to be severe.
Monday, June 7, 2010
Severe Weather Potential. . . Tonight and Tomorrow
The next image is the reflectivity from the same time, with an arrow and a circle placed into and around the area where the tornado is likely forming. The line indicates the inflow into the thunderstorm. This is a classic example of a 'hook echo' with a supercell.
These thunderstorms will likely form into an 'MCS', or 'mesoscale convective system'. They are very far north and west of KC- nearly 400 miles away. They will near our region very late tonight into early tomorrow morning, and may even affect going to work traffic. Northern Missouri has the best threat to see any thunderstorms, mainly north of Highway 36. As they continue on their path, they might dip into the area, but right now I somewhat doubt the contact of the MCS with Kansas City. For the high, I'm thinking we'll reach 90-95 if, and only if, the MCS doesn't come into contact with KC and we are able to clear the clouds out bringing us sun and daytime heating. If we do have rain and thunderstorms tomorrow, mainly in the morning to late morning, we may only get up to 85 or so, and that high may come before the MCS reaches KC. If the MCS does impact KC, strong wind gusts and maybe some large hail would be the threats. But, if we have time to heat up tomorrow, then the main threat would be later in the afternoon as the warm front/cold front approaches KC. These thunderstorms would likely be very severe, with very large hail and damaging winds the greatest threats, although we may have a few tornadoes, especially along and just south of the front which is forecast to be near I-70. However, the tornado threat is still relatively low. I'll update if I get new model data, but enjoy a few quiet hours and be ready for storms tomorrow!
And a quick note to anyone in northern MO- heavy rain is likely with this MCS, maybe on the scale of up to 3". Flash flooding is likely in these areas, so remember to avoid low lying areas, and to never drive across water-covered roadways. Pay close attention to NWS Flash Flood Warnings.
Tuesday, June 1, 2010
June 1st
Severe thunderstorm warnings have been issued for this entire line of thunderstorms north of KC. Here is a Level III NEXRAD image from 10:00PM with the warned areas indicated by the red polygons:
These are very intense thunderstorms but there are some signs that they may be weakening. A 90MPH wind gust was reported with these storms earlier. I still expect these storms to weaken as they push southeast and I believe that they'll impact KC with heavy rain, winds, and hail all below severe levels. I'll update tonight if things change, but if you live north of the metro, please keep a close eye on these thunderstorms. While the tornado threat remains very, very low, a damaging wind threat appears possible for at least another hour. Remember that damaging winds can and do cause damage just as expansive as that caused by tornadoes.
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It's June! School's out and warm weather is in- 90 degrees and higher in the sun in most locations this week. But, when it's not warm and muggy thunderstorms seem to be popping up, and strong storms formed in JOCO earlier today prompting a severe thunderstorm warning and triggering some marginally severe hail near Olathe- along with some strong wind gusts and heavy rain. But, for tonight, there is a threat of some thunderstorms (possibly severe) in and around the KC area. Here's a view of the NEXRAD image from 9:15PM this evening:Gentry, Harrison, and Worth counties in northern MO are currently under severe thunderstorm warnings. As this is very time sensitive, by the time anyone reads this the warnings will most likely have moved on. The greatest threat with any of these storms will be nickel sized hail and very strong winds, possibly pushing 70MPH in the most dangerous severe thunderstorms tonight. By about midnight, most of us here in KC should start to hear thunder in the distance and maybe see some lightning. 2AM and later is when we can expect to see any thunderstorms-pea size hail and gusty non-severe winds are possible. Heavy rains, maybe a flooding threat in low-lying areas, will also be likely. For a specific severe threat, I'd have to say that KC's threat is extremely low, and by midnight, most of the mid- and upper-level winds, along with the LLJ (low level jet) will have relaxed enough to diminish the severe threat. Before midnight, areas in northern Missouri will continue to have an isolated severe wind threat.
Tomorrow's forecast is incredibly difficult- the front that is accompanying these severe thunderstorms will stall (and disintegrate) across the area tomorrow morning, and after some early thunderstorms, another 80-90 degree day is likely. By afternoon, the weakening stalled front may (will) provide a focus area for thunderstorm development. Wind shear numbers aren't looking great, but instability is looking rather extreme, and any variation in wind shear forecasts could really spike a severe weather forecast. For now, I'd say marginally severe hail and strong winds will be likely with any thunderstorms tomorrow afternoon. If some of the atmospheric wind profiles can pick up a little bit, we may see a higher severe hail threat, and maybe the potential for an isolated tornado or two in the region, but right now winds aren't looking very supportive of a tornado threat.
For the weekend, the jet stream will sag southward and set up a very strong upper level wind force above the KC area, and will allow any surface lows and disturbances to ride this very powerful stream across the area. So, any SFC lows that move towards the area from Saturday through next Wednesday will need to be watched very closely for an increased hail and tornado threat. By June 15th, the tornado threat for our area will be over, and the rest of the summer should be marked by classic summer thunderstorms. I'll keep this updated the next few days, but enjoy some comfortable weather in the shade, and keep an eye to the sky through tomorrow, and this weekend.
Sunday, May 23, 2010
Warmer Weather!
Friday, May 14, 2010
Theory. . .
Wednesday, May 12, 2010
Thunderstorms Rapidly Intensifying. . .
12:24 AM UPDATE
After having a little panic attack there (haha), I'm beginning to analyze what happened, and what may still be happening, however I think the bow echo is now, truly, just that- strong, straight line winds. As it intensified east of Topeka, it absorbed many atmospheric disturbances. . . remnants of thunderstorms from earlier today, existing showers, heating from the surface, etc. Riding the cold front, it's easterly movement with winds from the west, and our winds from the south with the passage of the warm front earlier directly contrasted with each other. This created a situation where small, brief tornados could easily develop with any environmental trigger. . . like some of the existing low level clouds and showers over JOCO/Wyandotte from earlier. With the wind contrast and the surface disturbance, shear likely increased, and the updraft-veritcle rotation situation that occured allowed for a brief but scary spin up of a torando, possibly in numerous location. Many damage reports have come from JOCO in the last hour, with 'microburst' type damage, power outages, trees through houses, windows out. . . I've talked to a few people from my area in northeast JOCO who heard the same 'train roar' or loud 'whoosh' noise, something generally assosciated with tornados- especially the pressure drop evidenced by ears popping. So, while these tornados (if they were, remember this is not confirmed) were brief, they were potentially strong. Straight-line winds usually don't blow out windows and send trees through the house. . . they can do quite a bit of damage but that's a stretch. A microburst is possible, but downdrafts indicated a brief tornado threat was more likely. I mentioned this threat before the bow echo came through KC, and obviously it did cause some issues. . . many areas of rotation, many small spin ups likely happened. We'll know in the morning.
For the rest of the night. . . this line of strong thunderstorms will affect central and eastern Missouri, but is currently below severe limits and will likely stay that way. Penny sized hail and 50 mph wind gusts are possible.
More storms are moving up I35 from Emporia towards KC, these too could produce gusty winds and penny sized hail. Right now, I don't believe they will intensify, as our environment is more stable with the passing of the cold front. If something changes, I'll let you know. Flooding will continue to be a threat tonight into tomorrow morning.
This was an interesting night. . . I'll discuss it more tomorrow. Have a good, safe night everyone!
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I went ahead and deleted this portion of the blog as it contained mostly time-sensitive information about warnings.
Severe Weather Update
The line of thunderstorms (none currently severe warned) out to our west by 1 or 2 hours is beginning to bow out, showing signs that some of the winds on the leading edge of these storms is meeting or exceeding severe limits, and a parts of the line have exhibited signs of brief lower-level rotation when they overtook other, smaller, thunderstorms. These may become severe warned with a risk for up to 60-70 mph winds, and a very, very, slight chance for an isolated tornado-
and, well mid-blog the NWS in Pleasant Hill has issued a SEVERE THUNDERSTORM WARNING for Leavenworth and southeast Atchison counties in KS and western Platte county in Missouri until 11:15 PM.
The latest velocity scan out of the Topeka NEXRAD is indicating surface winds pushing 70 mph. Also, the latest scans have indicated a strengthening surface rotation couplet south of Lawrence. I'll watch these storms for the next half an hour or so and update on any new developments.
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All severe thunderstorms in the area have weakened. Flash flood warnings remain in effect for most of the metro until 5:30 AM tomorrow. The tornado watch will expire at midnight along with the severe thunderstorm watch. With the warm front barely clearing KC and strong capping, the severe threat didn't get as dangerous as it could have been. While our thunderstorm outlooks varified (statistically speaking), the situation didn't end up being quite as dangerous as it could have been. For the rest of the night, flooding, which is the #1 cause of weather-related death in the U.S. will be the main threat. Lots of lightning and the potential for some pea size hail to marginally severe quarter sized hail in the stronger storms should be the extent of the remaining threat tonight. A severe thunderstorm watch may replace the current watches across the area at midnight. I'll update if anything very significant materializes- but right now I don't think there's much of a tornado or damaging wind threat tonight. Tomrrow will be much cooler (most of the day in the 50s!) and rainy through the morning. We'll summarize the severe weather reports from today tomorrow evening. Have a good night!
Thunderstorms Forming. . . Outlook Update
Tuesday, May 11, 2010
Latest Model Trends
- Before 12PM- showers and thunderstorms around, moving to the north. Pea sized hail, gusty winds, and lightning are likely. Severe hail isn't out of the question but is becoming increasingly less likely.
- 12PM-5PM- skies will clear out and temperatures will climb to around 80 degrees, with an extremely humid summer-like airmass in the city. Clouds may start to build toward the end of this period. Pay close attention to forecasts for later in the night.
- 5PM-10PM-Our confidence in a SIGNIFICANT SEVERE WEATHER EVENT for KC is growing with each model trend. During this time, destructive hail, severe wind gusts, and tornados will be possible with any storms that develop. Make sure you stay up-to-date with the latest forecast information. Also, ensure that you and/or your family have a severe weather plan ready to be implimented should a tornado and/or severe thunderstorm warning be issued for your area.
- 10PM and on-Another round of severe weather is possible as the cold front moves through. Very large hail and damaging winds are possible, especially if a bow echo can form. The tornado threat is relatively low with these storms, but the formation of a couple of brief tornados is not all that rare on the leading edge of a bow echo.
My updated outlook is below. Remember, things still can change, but let's hope for the best, and prepare for the worst. Have a good night everyone, keep in mind tomorrow will feel so much better than all these cold days we've been having- and, the severe risk, while significant, should only last a few hours in the evening.
A Recap of Yesterday and Model Trends
I'll update later tonight or in the morning. So many questions in this forecast- I hope my analysis made some sense. Have a good night and keep an eye on the weather for tomorrow evening.
SPC Outlook Update
Monday, May 10, 2010
Late Night Trends
Storm reports, OKC tornado picture. . . awaiting storms in KC
Thunderstorms are moving through KC with pea sized hail and non-severe wind gusts in some areas. The warm sector will remain south of KC and all severe weather will remain south of a Lyon Co. KS to Henry Co. MO line, well out of the Pleasant Hill NWS's warning area. As the low that you see in the surface map (below) moves northeastward, the warm front will begin to recede and the system should be taken over by the incoming cold front. Fortunately, this cold front shouldn't spark any severe weather, and temperatures behind the front aren't more than 5 or 10 degrees different than those here as we still are struggling to get above 52 or 53 degrees.Severe hail and wind gusts will be possible in far south and southeast KS, extreme southwest MO, far northwest AK, and, along with a continued risk for isolated strong and long-track tornadoes, through eastern OK into north central and northeast Texas. This activity will all be between the dry line (shown on the map in tan) and the warm front (in red) where the warm sector is promoting a very unstable environment, something we lack here, effectively eliminating all severe weather threat for Kansas City.
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Incredible number of large tornado reports in south KS through central OK. . . interestingly enough all but 5 or 6 of the numerous reports were in the moderate or slight risk area. The high risk continues to see a destructive tornado moving across its southern reaches, the same storm that caused a fatality in Norman and has had a strong, wedge tornado on the ground for more than an hour. The 2nd picture below is from KWTV OKC, showing the massive tornado in south OKC. Here in KC, the thunderstorms may enter the area before 9, with marginally severe hail the largest threat. Some recent model runs are suggesting increasing warmth into the KC region, however I believe the majority of this will stay well south of the metro. Right now, I think the chance of any severe weather here in KC is slim.
Watching and Waiting
Monday Night Outlook
Sunday, May 9, 2010
Sunday Afternoon Update
Early AM Update
Saturday, May 8, 2010
Late Saturday Thoughts on Monday
A POTENTIALLY VOLATILE SETUP EXISTS ACROSS THE OUTLOOK AREA MONDAY EVENING AND OVERNIGHT...WITH TORNADOES...LARGE HAIL AND DAMAGING WINDS ALL POSSIBLE AS SUPERCELL THUNDERSTORMS TRACK EASTWARD...ALONG WITH THE THREAT OF FLASH FLOODING.
11:30 EDIT
Not much different in tonight's 00z runs for 00z Tuesday (7PM Monday). Low should still be well to the southwest, and a number of the different models indicate highest cape levels will be south and southwest of the city where a very large outbreak of tornadoes will occur. As for KC- right now it appears that we'll be located in the warm sector, but that storms will reach us likely sometime around 10PM Monday if models verify. CAPE/Craven-Brooks levels remain surprisingly low. . . but other instability/supercell/tornado parameters are supportive of continued tornado threat in the thunderstorms reaching us late in the night, which the NWS echos in their latest outlook. To me, far southeast KS and northeast OK has the highest threat of dangerous storms, and as long-term CAPE outlooks are often somewhat deceptive. . . I would say forecasts for this area will continue to need close attention. While I think it is apparent that large hail and winds will threaten the area, the tornado threat is a little less clear. The NWS and SPC seem to be sold on a higher threat for KC, but I am not.
If I was to make a forecast right now, I would say storms will fire very late in the evening along the dryline up to the triple-point, and a significant tornado situation will likely unfold from east OK into southeast KS, moving into extreme west MO and NW AK overnight. As the thunderstorms retain their surface based supercellular structure but move into an area of lower instability, a very large hail threat will likely evolve for the metro area.
However, that may change. I will update with the 1AM Day 2 SPC convective outlook, and see where things stand then. Shear values are off the charts for tornadoes here, although I believe instability may be in question Monday night. Lets see how the SPC interprets things in a couple of hours, and I'll look back through the model runs to see if I can corroborate what they are predicting.
For now, please pay close attention to Monday night's forecast. . . as a very dangerous situation will likely evolve somewhere in this region, but how widespread and late that will continue for is a matter to be reviewed many more times.
Monday's Complex Setup
NWS EAX forecast discussion updated; appears that local forecasters believe the supercells may persist long enough to enter our area and, especially with the triple point so close by, continue to have the potential to contain tornadoes. The relevant part of the discussion follows.
SEVERE THUNDERSTORMS SHOULD ERUPT THROUGH CENTRAL PORTIONS OF KANSAS. GIVEN THE AMPLE SHEAR AND THE ORIENTATION OF THAT SHEAR ACROSS THE DRYLINE SUPERCELLS WILL BE LIKELY. THIS ACTIVITY WILL SHIFT TO THE EAST WITH THE TRIPLE POINT LIKELY TO BE IN WESTERN PORTIONS OF THE FORECAST AREA. WHAT IS VERY CONCERNING WITH THIS POTENTIALY SIGNIFICANT SEVERE EVENT IS THAT DUE TO STRONG FORCING AND STRONG SURFACE WINDS...THE ENVIRONMENT MAY STAY SURFACE BASED WELL INTO THE EVENING AND EVEN CLOSE TO MIDNIGHT. WITH HIGH HELICITY VALUES WITHIN THE WARM SECTOR AND VERY HIGH SHEAR WE COULD SEE SUPERCELLS PERSISTING WELL AFTER DARK WITH TORNADOES A DISTINCT POSSIBLY.
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3 days away from a massive storm system that will eject into the plains creating the potential for significant severe weather, and yet the forecast is still too complex to make any accurate predictions. The latest SPC SREF (short range ensemble forecast) run will be out at any time. . . and if it's anything like the last run, KC will be deep within the prime zone for supercell development, and on the edge of an unusually high (5-7) significant tornado parameter. Interestingly, the SREF models have been trying to push to dryline with 60+ dew points farther north and east. Today's GFS and ECMWF runs have kept the surface low in far south central KS for 00z (7PM) Tuesday, and keeping the highest CAPE values in north OK and south KS- possibly over 3000 j/kg. The SREF runs have KC on the northeast edge of high Craven-Brooks parameters, and within an area of significant tornado ingredients sometime after 00z Tuesday. It looks as though the LLJ (low level jet) will force the dryline very quickly to the north and east, along with the SFC (surface) low, moving north of KC sometime in the early morning hours of Tuesday. Whether or not the cold front will overtake the dryline and whether or not KC will be north or south of the warm front will likely be major players in our severe weather threat. If strong low level winds push the cold front into the dryline, our severe weather threat would primarily be late night linear hail producers and strong wind gusts. If the dry line can stay isolated from the cold front, then shear profiles will likely be more favorable for continued supercell thunderstorms late into the night, although eventually a linear squall will develop somewhere. Thunderstorms are likely earlier in the day as the warm front moves northward, and if the front stays south of KC late into the afternoon, large hail could be a significant threat right around the front. If the warm front moves through, extreme low level moisture and sufficient temps will put KC in the warm sector, and thunderstorms forming along the dryline, north to the triple-point, and points east will likely be supercellular with explosive development and a high probability for vertical rotation. Right now, the likeliest area for significant tornado development (primarily to do this area being protected from much of the model uncertainty) is south central / southeast KS into northeast OK sometime in the afternoon. If the low moves faster as some GFS runs have suggested or a strong cap holds until late evening, this risk area will likely shift closer to KC. We'll have to wait for further model trends before making an accurate prediction, one which will likely wait until Monday morning. Right now, none of the models seem to be able to consistently plot the warm front, putting KC in a zone of major uncertainty. Regardless, strong thunderstorms with large hail and gusty winds will be very likely overnight Monday into early Tuesday morning. But, our strategic placement within the warm sector and position of the SFC low/dry line will likely be major players in our supercell and tornado threat.
Somewhere in the plains there is likely to be a significant tornado outbreak- but where? We'll just have to speculate for now.
Below is the current GFS 00z surface setup for Monday night. Warm front position right now, like I said, is more of a guessing game than anything.