STORM2K

What an ongoing heat wave in the Midwest! Temperatures this afternoon in the 90s to 100s. Very dangerous heat indexes are occurring as I write this. Heat indexes in some locales approaching 120 degrees A tornado watch I believe is posted in parts of nebraska and a small part of Iowa. The National Weather Service in Council Bluffs Iowa currently has a temperature of 91 degrees which isnt so bad but with a dewpoint in the mid 80s the heat index is 116 degrees. The winds are southerly and the skies are fair. The dewpoint a little earlier went as high as 86 degrees. People when my family and I lived in Summerville we experienced heat indexes to that standard and it just about takes your breath away. Its like walking into a furnace. Here in Berea South Carolina we hit the upper 80s with our lows in the upper 60s. [Humidities in the 40s and dewpoints in the 60s] I bet you the people in the midwest wouldnt mind those dewpoints. In fact, I know they would'nt. When I hear about that kind of heat; I appreciate the foothills of South Carolina. To each is own.............

Did you say a dew point in the mid 80s? It was not that crazy today. (Council Bluffs is an automated station not under NWS quality control; Omaha's Eppley Airport is the main one used for the Omaha/Council Bluffs metro area.)

It was still a scorcher today! Thank goodness for the inventor of air conditioning.

The tornado watch has been canceled or just allowed to expire. That thermal cap has played havoc in most are Nebraska and South Dakota. Might see a chance later tonight, but better chances come Wednesday ahead of some MUCH cooler air!

NEWeatherguy wrote:Did you say a dew point in the mid 80s? It was not that crazy today. (Council Bluffs is an automated station not under NWS quality control; Omaha's Eppley Airport is the main one used for the Omaha/Council Bluffs metro area.)

It was still a scorcher today! Thank goodness for the inventor of air conditioning.

The tornado watch has been canceled or just allowed to expire. That thermal cap has played havoc in most are Nebraska and South Dakota. Might see a chance later tonight, but better chances come Wednesday ahead of some MUCH cooler air!

Hey, Brian I am so sorry for the error I made yesterday on that weather observation. Iam glad you pointed that out to me. How hot did you actually get?

I'm not completely postive about Eppley or Offutt AFB, but the Gretna station go up to 94°F. The heat index was 116°F with a THSW Index (this is an index that accounts for temp, humidity, sun, and wind) hit 127°F.

I have commonly seen every year with a lot of the automated stations in Iowa (particularly), and Muscatine the leading candidate in heat wave situations with high humidity, this locale comes in routinely with dewpoints in the low 80's and occasionally 84º or 85º dewpoints.

Whether or not the observations can be constituted as accurate is beyond me ... but in several heat wave scenarios, the surrounding offices also registered nearly the same heat, and somehat lower humidity/dewopint couplets (generally upper 70's to maybe 80º-81º dewpoint) ...

SF

jeff and shirens weather wrote: Hey, Brian I am so sorry for the error I made yesterday on that weather observation. Iam glad you pointed that out to me. How hot did you actually get?

It is not your fault! Actually the mercury on Tuesday topped out at 95 at Eppley, which is near a river but close to downtown. The Valley NWS, which is western suburban, reach 93. Basically anything over 90 with these types of dew points is yucky in my opinion!

Stormsfury wrote:I have commonly seen every year with a lot of the automated stations in Iowa (particularly), and Muscatine the leading candidate in heat wave situations with high humidity, this locale comes in routinely with dewpoints in the low 80's and occasionally 84º or 85º dewpoints.

Whether or not the observations can be constituted as accurate is beyond me ... but in several heat wave scenarios, the surrounding offices also registered nearly the same heat, and somehat lower humidity/dewopint couplets (generally upper 70's to maybe 80º-81º dewpoint) ...

SF

You are right on that one. Yes I have seen small 15 to 20 degree errors from Iowa stations, but one year, everyone was reporting 90s, except one western Iowa automated location: they were in the 30s. Goes without saying that the temperature graphic with the colors automatically configured by the computer sure had a heck of a bozi!

A Sioux City tv station reported a dew point of 80 in the early morning hours. Which wasn't to far off from everybody else, 72-77 dewpoints.

NEWeatherguy, did you happen to get any storms last night or tonight yet?? I got one last night, put down .77 inches of rain, some real nice lightning. But nothin severe until an hour or so later in central Iowa.

NWIASpotter wrote:A Sioux City tv station reported a dew point of 80 in the early morning hours. Which wasn't to far off from everybody else, 72-77 dewpoints.

NEWeatherguy, did you happen to get any storms last night or tonight yet?? I got one last night, put down .77 inches of rain, some real nice lightning. But nothin severe until an hour or so later in central Iowa.

You are correct with the 80 degree dew point, so perhaps the Council Bluffs reprot was not too far fetched. Here in Omaha, the daybreak news at 5am-7am, reported temperatures still in the mid 80s!

Last night, things fizzled up north. Tonight, I think the same thing will happen, but later. They may perhaps make it to the Missouri River and western Iowa later tonight early Thursday, but I am not expecting much. There is one ugly cell in Holt County, NE, but that is about it.

We may see some storms THursday afternoon and evening as a cold front moves through, and then, mid to upper 70s for HIGHS in mid to late July for the weekend.

Yea, thats going to be great. I got up to 88 today, tomorrow we might barely get to 80. But it looks like storms are going to be quite until Sunday maybe.

NWIASpotter wrote:Yea, thats going to be great. I got up to 88 today, tomorrow we might barely get to 80. But it looks like storms are going to be quite until Sunday maybe.

I am a bit shocked about Sunday;s chance, but perhaps maybe some cooler temperatures aloft and some afternoon sun may kick a storm or two off.

Maybe, I haven't had time to look at many of the models or NWS discussions. Next week I got a couple of trips to Omaha, and St. Cloud, so maybe I can get something while I'm away from my home up here in NW IA.

NWIASpotter wrote:A Sioux City tv station reported a dew point of 80 in the early morning hours. Which wasn't to far off from everybody else, 72-77 dewpoints.

NEWeatherguy, did you happen to get any storms last night or tonight yet?? I got one last night, put down .77 inches of rain, some real nice lightning. But nothin severe until an hour or so later in central Iowa.

Last night and late this afternoon we got some very good storms didnt chase the July 20th storms because it was dark...But did chase the 21st ones.. saw a very nice cell coming straight down the river we went up highway 14 and pulled off to a gravel road saw some nice wall cloud but non rotating ........but the shelf cloud was sure fun to watch we got about 70 mph winds estimated it flattened all the corn around us so it was pretty exciting....to bad I don't own a digital camera

Yea, digital cameras are a big help. Since the storms here were around 1 am, I was getting good lightning shots with my digital camera. You gotta like them because you just delete the pictures within seconds and have more room.

Wow, a heat index that high would be pretty bad.

Your telling me W13, heat index in northwest Iowa only hit around 105, ONLY. Over in Nebraska they had some heat indices around 120. It was actually too hot for any storms to form here, CAPE values were upwards of 6000 J/kg, everything was there, the CIN was too much.

NWIASpotter wrote:Your telling me W13, heat index in northwest Iowa only hit around 105, ONLY. Over in Nebraska they had some heat indices around 120. It was actually too hot for any storms to form here, CAPE values were upwards of 6000 J/kg, everything was there, the CIN was too much.

Strong subsidence from upper level highs (heat ridges, etc.) tend to cap things pretty effectively. These setups, warm noses anywhere from 600mb to 850mb prevents any sufficient enough lapse rates for convection to develop, let alone any clouds. Convective temperatures are ridiculously high, and the heat feeds itself with that subsidence.

SF

NWIASpotter wrote:Your telling me W13, heat index in northwest Iowa only hit around 105, ONLY. Over in Nebraska they had some heat indices around 120. It was actually too hot for any storms to form here, CAPE values were upwards of 6000 J/kg, everything was there, the CIN was too much.

I doesn't matter if you have CAPE of > 9000 J/kg, if convective temperatures aren't reached, and LFC heights are too high (both a function of CIN) convective initiation wont take place.

Deep convection becomes MOST likely where there is a smaller difference between the LCL and LFC height (or when the LFC is close to the ground). THEN if you have outrageous CAPE values on the order of 6000 J/kg things can get going very quickly in a ROUGH manner.

Sufficient lift is required to overcome the CAP so that parcels can reach the LFC.

Yes, I realize this. LFC and LCL were apart by about 75 mb according to GOES. Convective temp if i remember right was 34 degrees celcius. Which isn't too bad for how hot we were. LI were -7, so everything was there like I said. The temps at 800 and 650 were very high, so I know there was a strong cap. So I understand why they didn't form, but thanks for the info anyway.