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Saturday, July 29, 2023 Thunderstorms


weatherwiz
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***THIS IS NOT GOING TO BE A SEVERE WEATHER OUTBREAK CONSISTING OF HIGH-END SEVERE WEATHER ***

 

With that out of the way, Saturday features another similar scenario with a shortwave tracking across north-central New England. This shortwave is not de-amplifying like Thursday's shortwave and the response from this will be stronger height falls region wide which will help aid in large-scale lift and good wind shear with bulk shear values in the 40-50 knot range. These values will be more than sufficient to aid in updraft organization and should help thunderstorms quickly develop into one or multiple lines. One thing to note, however, is we do not have an advancing warm front to aid in low-level wind shear, thus any tornado potential this go around is much lower.

We remain within a rather rich low-level theta-e airmass and the combination of surface temperatures well into the 80's to lower 90's with dewpoints into the lower 70's should contribute to moderate levels of CAPE once again characterized by mixed-layer CAPE values in the 1500-2000 J/KG range. The degree of instability will be held back once again by poor mid-level lapse rates and warm mid-level temperatures. 

Given the combination of strong shortwave forcing, decent height falls, moderate instability, and strong bulk shear, numerous thunderstorms should quickly develop moving through the early-to-mid afternoon. Strong bulk shear and predominately unidirectional flow will quickly allow convection to become organized and grow upscale into one or multiple lines. 

Damaging Wind Potential: The key regarding the damaging wind potential will be how steep the low-level lapse rates (particularly within the 2-6km layer). As mentioned above, low-level wind shear isn't particularly strong. There isn't much of a low-level jet to mix down. This means intense updrafts would have to develop to aid in downburst potential. On Thursday, despite the strong surface heating that materialized, we were never able to really steep the low-level lapse rate which can be a big discriminator in damaging wind vs. non-damaging wind events. There are hints, however, the low-level lapse rate could be steeper tomorrow. 

We will likely see a similar scenario to Thursday where we see a localized, but concentrated area of wind damage. This will not be widespread. 

Hail Potential: Very low hail potential given the poor mid-level lapse rates, warm mid-level temperatures, and subsequently, high freezing levels. Smaller hail is possible, but would take some significant updrafts for hail. 

Tornado Potential: Much lower then Thursday. 

Flash Flooding: Localized flash flooding is very likely given the already saturated grounds and potential for some training storms in spots. 

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@weatherwiz just a tad windy in IA tonight

Severe Weather Statement
National Weather Service Quad Cities IA/IL
817 PM CDT Fri Jul 28 2023

IAC031-097-105-113-290200-
/O.CON.KDVN.SV.W.0205.000000T0000Z-230729T0200Z/
Jackson IA-Cedar IA-Jones IA-Linn IA-
817 PM CDT Fri Jul 28 2023

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CDT
FOR SOUTHWESTERN JACKSON...NORTHERN CEDAR...JONES AND LINN
COUNTIES...

At 817 PM CDT, severe thunderstorms were located along a line
extending from near Buck Creek to Squaw Creek Park, moving east at 65
mph.

THESE ARE DESTRUCTIVE STORMS FOR PORTIONS OF EASTERN IOWA.

HAZARD...100 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters.

IMPACT...You are in a life-threatening situation. Flying debris may
         be deadly to those caught without shelter. Mobile homes
         will be destroyed. Expect considerable damage to homes and
         businesses. Expect extensive tree damage and power outages.

Locations impacted include...
Cedar Rapids, Anamosa, Mechanicsville, Stanwood, Marion, Hiawatha,
Mount Vernon, Monticello, Robins, Center Point, Cascade, Lisbon,
Fairfax, Ely, Walford, Central City, Springville, Palo, Lowden and
Olin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4229 9078 4203 9083 4203 9090 4184 9090
      4186 9183 4230 9176
TIME...MOT...LOC 0117Z 280DEG 57KT 4230 9136 4200 9158

THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...100 MPH

 

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3 minutes ago, yoda said:

@weatherwiz just a tad windy in IA tonight

Severe Weather Statement
National Weather Service Quad Cities IA/IL
817 PM CDT Fri Jul 28 2023

IAC031-097-105-113-290200-
/O.CON.KDVN.SV.W.0205.000000T0000Z-230729T0200Z/
Jackson IA-Cedar IA-Jones IA-Linn IA-
817 PM CDT Fri Jul 28 2023

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CDT
FOR SOUTHWESTERN JACKSON...NORTHERN CEDAR...JONES AND LINN
COUNTIES...

At 817 PM CDT, severe thunderstorms were located along a line
extending from near Buck Creek to Squaw Creek Park, moving east at 65
mph.

THESE ARE DESTRUCTIVE STORMS FOR PORTIONS OF EASTERN IOWA.

HAZARD...100 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters.

IMPACT...You are in a life-threatening situation. Flying debris may
         be deadly to those caught without shelter. Mobile homes
         will be destroyed. Expect considerable damage to homes and
         businesses. Expect extensive tree damage and power outages.

Locations impacted include...
Cedar Rapids, Anamosa, Mechanicsville, Stanwood, Marion, Hiawatha,
Mount Vernon, Monticello, Robins, Center Point, Cascade, Lisbon,
Fairfax, Ely, Walford, Central City, Springville, Palo, Lowden and
Olin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4229 9078 4203 9083 4203 9090 4184 9090
      4186 9183 4230 9176
TIME...MOT...LOC 0117Z 280DEG 57KT 4230 9136 4200 9158

THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...100 MPH

 

Some around here would meh getting 80 instead of 100 gusts :weenie: 

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31 minutes ago, WinterWolf said:

Sometimes the second round is the better gig…we’ve seen that happen in winter too. 

I can’t recall a heat wave that was bookended by convection. Back in the day at least, it seemed that heat almost always goes out with a bang. 

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Some garbage rains in CT now mid morning messing up the chance of getting those steep low level lapse rates , you hate to see it , thou maybe some one still sees good storms late 

and wxwatcher if SNE had 70 mph winds in a few reports in Eastern areas “everyone” would have cream in their pants , some would be upset they got nothing but they would acknowledge the day was Part of a significant Outbreak ..but as we know ..not gonna happen 

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Most everyone is at least going to get some degree of rain. Some of the CAMS hint at some discrete cells this afternoon, but the main show is going to be vey late afternoon and early evening. Will see some very good lightning producers and probably another concentrated swath of wind damage. 

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3 minutes ago, weatherwiz said:

Most everyone is at least going to get some degree of rain. Some of the CAMS hint at some discrete cells this afternoon, but the main show is going to be vey late afternoon and early evening. Will see some very good lightning producers and probably another concentrated swath of wind damage. 

Bring it.

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Not sure why Wiz' thinks this scenario is going be such a high end widespread occurrence of tornadoes hurling bowling ball hail like rocks out of a lawn mower ... particularly when it's being attenuated by a morning band of thread killer light rain poison ... :facepalm:

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2 minutes ago, Typhoon Tip said:

Not sure why Wiz' thinks this scenario is going be such a high end widespread occurrence of tornadoes hurling bowling ball hail like rocks out of a lawn mower ... particularly when it's being attenuated by a morning band of thread killer light rain poison ... :facepalm:

He actually said it isn’t gonna be anything particularly strong in his opening statements. 

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