Increase in hail size for warning criteria

It took nearly 20 years, over strenuous objections from USAF & EM, to get 1" into the system. And it's still not nationwide. I'd vote for golf balls too, but we'll be retired before that can happen ;)
 
I personally think the 1" criterion would better suite the goals of the National Weather Service, as well as cut down the number of "That was a severe thunderstorm?" from the general public. 3/4" hail really doesn't do damage to property unless it is wind driven at speeds over 60 mph, in which case the svr warning verified for damaging wind!
 
3/4", I think is a good standard.
It is a good indicator that the cell can produce large
hail and has a good chance of producing
even larger hail.

1" is thought to be the beginning size of "damaging hail"
But I also think a hard (not slushy or soft) 3/4" hail
stone with some wind behind it can also do some damage.

If you get enough 3/4" hail you can start seeing some
crop damage.
This is a big concern for farmers etc. and the $$$'s in damage
can add up quickly.


Tim
 
I agree with Tim, 3/4" hail can be damaging to cropping, especially if there is some wind behind it. Horticultural crops in particular are very vulnerable to damage to hail of that size.
 
Tim Shriver said:
3/4", I think is a good standard.
It is a good indicator that the cell can produce large
hail and has a good chance of producing
even larger hail.
Click to expand...

Actually no... Most 3/4" hail reports are associated with just 3/4" hail storms.

If you get enough 3/4" hail you can start seeing some
crop damage.
Click to expand...

And you can still get that info from the SPS which will be issued for 3/4" hail... But a question - what do farmers do to protect their crops when they find out a hailstorm is coming?
 
When this topic came up on this board, I asked our local WCM (from the Mount Holly, NJ office) if anything was going to happen in the eastern region related to this. Initially, he said he hadn't heard anything. Out of the blue this week he told me that he had just heard that eastern region offices will very soon be changing the hail size warning criterion to 1" (and that there was no recent discussion of this among the WCMs ... eastern HQ decided to mandate this without much discussion) ... unless there are strong objections/complaints from emergency managers or the general public. So, this change may get adopted nationally pretty quickly.
 
Great news! USAF & some EM's fought this VERY hard back in the 90's, hopefully with NWSChat and other forms of getting out the 3/4" hail info -- they'll be satisfied and the public might have a little more faith in SVR's!
 
rdale said:
Actually no... Most 3/4" hail reports are associated with just 3/4" hail storms.



And you can still get that info from the SPS which will be issued for 3/4" hail... But a question - what do farmers do to protect their crops when they find out a hailstorm is coming?
Click to expand...

When was the last time someone moved their house to
get out of the way of a tornado?

You will also find that insurance companies will ask if a warning was issued or
if a watch was in affect. This does affect insurance rates and claim payouts to farmers
from insurance companies.


As for the hail, I think we both could prove our points.

Tim
 
Last edited by a moderator:
Tim Shriver said:
When was the last time someone moved their house to
get out of the way of a tornado?
Click to expand...

Hmmm... Not sure I get the connection. Warnings are issued for the protection of life. If you can protect property, then so be it. But again - how will changing 1" criteria affect farmers?

Tim Shriver said:
Life and property, as the saying goes.
Click to expand...

Actually -- no. You can't take property with you. Your life is more important than any physical object, so having insurance doesn't mean it's okay for people to die. The goal of warning is to save lives, and 3/4" hail doesn't kill.
 
I have a question about lightning in severe thunderstorms. Has there been any studies on cloud to ground lightning related to hail size during thunderstorms. Alot of severe thunderstorm warnings now with the 3/4 inch hail criteria have wording containing this storm also contains deadly lightning with it. I know the NWS does not issue severe warnings for lightning alone for obvouis reasons but was just wondering if any studies have been done on lightning related to hail size.
 
Are you talking about the frequency of lightning? I'm not sure our hail database is good enough to correlate that, but I'd lay odds that there's no way to say "xx strikes per minute = 3/4in hail, yy strikes per minute = 1in" etc.
 
I guess my point is why would you want to raise the hail criteria to 1" from 3/4" when you have deadly lightning occuring in alot of 3/4" hail storms. Since NWS does not issue warnings for lightning i think leaving 3/4" hail criteria would be a good idea just for the chance to warn people of the deadly lightning occuring in these storms. Remember the goal of the warning is to save lives. I agree the 3/4" hail doesn't kill but the lightning can. I know you dont need 3/4" hail for lightning to occure,but raising the criteria for hail takes away a chance to warn the public of the deadly lightning occuring in these storms.
 
Lightning has a warning method that is MUCH better than any human or computer generated system on the planet...

It's called --- thunder. People will hear and heed thunder much more often than they would a "lightning warning."
 
rdale said:
Lightning has a warning method that is MUCH better than any human or computer generated system on the planet...

It's called --- thunder. People will hear and heed thunder much more often than they would a "lightning warning."
Click to expand...
Thunder always has negative lead time. Unless the lightning hits you. Then it is zero lead time.

Stats indicate that a large spike in lightning related casualties are from the first CG strike of the storm. If I find references, I'll post them.
 
I'd believe that stat.

I still don't think that means we need to issue SVR's on 3/4 inch hail because they produce deadly lightning. If they are at the point of 3/4" hail, they are already producing lightning.
 
Example of hail reports for 23 counties in the NWS Grand Rapids CWA.

Quick glance at the NCDC Storm Events Database minus 2 months of data,
shows the following:

There was 1,062 hail reports of 3/4 inch or higher.
If you used, 1.00 inch or higher, there was only 506 reports.
556 of the hail reports were less than 1.00 inch.(52.4% of the reports)

I am all in favor of raising the hail criteria to 1.00.
 
The current warning criteria for a SVR is 3/4" hail and/or winds that are gusting to or higher than 58 mph. There is not a criteria for lightning. If we're going to discuss the warning by the book, we should only be discussing the hail or wind. In this thread's case, it's the hail size threshold.

Lightning production in severe storms varies greatly. If warnings were issued on storms due to the lightning, the number of warnings would increase dramatically. FWIW, many offices already issue SPSs (Signficant Weather Alert) for strong storms that don't reach severe thresholds. If there's going to be a separate discussion on the merits or demerits of using lightning as a criteria, it should probably be in a separate thread.
 
FWIW some of the most intense lightning events I've witnessed have been in non-severe storms. Severe storms tend to have more frequent CG lightning, but not always. With the exception of a few (namely Mulvane and Kent County, TX), supercells tend to be very infrequent CG producers - when they do it's mainly in the forward flank precip area.
 
I agree with Chris Nuttall here. Lightning has no role in whether a storm is severe or not. Storms are not warned on because they have lightning. If they were, every thunderstorm would have to be considered severe.

I agree that the hail criteria should be "upped" to 1 inch for severe. .75 inch hail is not going to do a whole lot of damage for the most part. Yea, it hurts vegetation, but a farmer can't put his crop in the garage until the storm passes.

Again, I think raising the criteria would do a lot more good than bad.
 
Received this from Chris Miller at ILX...

This afternoon we received the official word that the minimum hail criteria
for Severe Thunderstorm Warnings will be increased to 1.00" effective
April 1, 2009. For an informational web briefing from our regional
headquarters about this initiative, go to the following link:

http://www.crh.noaa.gov/crh/One_Inch_Hail_Podcast.wmv

For "near severe storms" with hail 3/4" to less than 1", and wind gusts
less than 50 knots (58 mph) we will be using our Special Weather
Statement (SPSILX/WWUS 83 KILX) product. We also use this for reports
of cold air funnels. This product is available on our webpage in a number of locations,
or you can go there directly at:

http://www.crh.noaa.gov/product.php?site=ILX&product=SPS&issuedby=ILX

This change in hail criteria does NOT change the size of hail that we want you
to report to us. Hail reports of ALL SIZES are very important to our severe
weather operations. Let Ernie or me know if you have any questions.
Click to expand...
 
Interesting that currently in Sacto valley, (California) only the shorterm cast mentions nickle-size hail (.85) as possible but no special weather statement to that effect:

--

Short Term Forecast

SHORT TERM FORECAST...CORRECTED
NATIONAL WEATHER SERVICE SACRAMENTO CA
910 PM PST MON MAR 2 2009

***** CITY OF NIXON CORRECTED TO DIXON *****

CAZ017-018-030645-
SOUTHERN SACRAMENTO VALLEY-CARQUINEZ STRAIT AND DELTA-
910 PM PST MON MAR 2 2009

.NOW...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF
HEAVIER SHOWERS WITH EMBEDDED THUNDERSTORMS IN IT. THE SYSTEM IS
MOVING NORTHEAST ALONG INTERSTATE 80 TOWARDS THE CITIES OF DIXON
AND DAVIS. HEAVY RAIN WITH NICKLE-SIZE HAIL AND GUSTY WINDS ARE
POSSIBLE WITH THIS SYSTEM. MOTORISTS TRAVELING WITHIN THIS REGION
ARE ADVISED TO SLOW DOWN AND INCREASE FOLLOWING DISTANCES...AND
WATCH OUT FOR PONDING OF WATER THAT CAN MAKE DRIVING DIFFICULT.

--
Earlier in day I heard a severe-t-storm warning for Amador and Calaveras county for similar situation. Where's the consistency?

Didn't see any reports either--despite the claim of a spotter here below. Maybe now that doesn't count as a report?

--
National Weather Service Issues Severe Thunderstorm Warning For The Mother Lode
Monday, March 02, 2009 - 03:20 PM
Bill Johnson
MML News Director
Monday Storm Drenches Sonora (03/02/09)

Sacramento, CA -- The National Weather Service has issued a severe thunderstorm warning for western Tuolumne County including Sonora and Calaveras County including San Andreas.

This warning will be in effect until 4pm.

Monday Storm Drenches Sonora (03/02/09)

At 3pm the N.W.S. Doppler radar indicated a line of severe thunderstorms capable of producting nickel size hail and gusty winds above 30 mph. These storms were located along a line extending from Grizzly Flat to Copperopolis to southeast of Waterford. The line is moving in a northeastly direction at 20 mph.

A spotter at Copperopolis has already reported nickel sized hail and wind gusts to 30 mph.
 
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