TS Allison

[Ptarmigan]

Here is a Power Point presentation in PDF file about TS Allison. In the presentation, it says that up to 33 inches of rain fell in 12 hours onn June 8-9, 2001!

http://www.floodsafety.com/media/pdfs/texas/ivey.pdf

[HURAKAN]

Great pictures. That's for posting this up. Allison was a true surprise. No one expected the storm to be so devastating after forming almost in a flash.

[Ptarmigan]

Great pictures. That's for posting this up. Allison was a true surprise. No one expected the storm to be so devastating after forming almost in a flash.

Yeah. I remember that the low pressure system that became Allison was not even forecasted to form. The area was unfavorable for development. Than somehow it formed. Had Allison stayed over the water longer, it could of been a hurricane.

[weatherguru18]

I'd argue that it was sub-tropical and was a mere depression...if that... by the time it devastated Houston. Oh how I remember Allison. Water got dangerously close to my house...and we're in like a thousand year flood plain or some crap like that.

[jeff]

The maximum 12 hour rainfall recorded was by ALERT station 1600 (Mt. Houston Rd at Greens Bayou) and was 28.3 inches. This was likely off by 2-3 inches due to the intense hourly rainfall rates and the inability of the tipping bucket to catch all the rain fall at that rate...however the official number is 28.3 in 12 hours. The same gage alose recorded 13.5 inches in 3 hours and 21.2 inches in 6 hours. The 4-day total was 38.6 inches.

ALERT station 1620 (Ley Rd at Greens Bayou) recorded 10.7 inches in 3 hours, 14.8 inches in 6 hours, 25.6 inches in 12 hours, and 33.7 inches in 4-days. A 1-hr total of 5.2 inches was recorded at this site.

The highest 1-hr total recorded was 6.3 inches at Halls Bayou and Jensen Dr.

the 1% rainfall rate based on TP 40 for Harris County is 4.8 inches, 6-hr is 8.8 inches, 12-hr is 10.5 inches.

The 28.3 inches in 12 hours is 15.7 inches above the 24-hr 1% rainfall rate of 12.6 inches.

[Category 5]

Interesting fact about Allison is that she originated as a Cape Verde wave, and took a trip to the EPAC before developing in the GOM.

[Cyclone1]

Interesting fact about Allison is that she originated as a Cape Verde wave, and took a trip to the EPAC before developing in the GOM.

Didn't the first Allison do something like that too, becoming Cosme in the middle?

The similarities between those two storms are mind blowing.

[Category 5]

Interesting fact about Allison is that she originated as a Cape Verde wave, and took a trip to the EPAC before developing in the GOM.

Didn't the first Allison do something like that too, becoming Cosme in the middle?

The similarities between those two storms are mind blowing.

Yes the remnents of Hurricane Cosme were involved.

[Ptarmigan]

I'd argue that it was sub-tropical and was a mere depression...if that... by the time it devastated Houston. Oh how I remember Allison. Water got dangerously close to my house...and we're in like a thousand year flood plain or some crap like that.

I have heard that TS Allison being a sub-tropical storm too. In fact read an article about it in the Houston Chronicles and I believe it was right before the devastating floods on June 8-9, 2001. It was asymetrical, with all the winds to the east. I remember not much wind from it when Allison made landfall.

[Ptarmigan]

Didn't the first Allison do something like that too, becoming Cosme in the middle?

The similarities between those two storms are mind blowing.

Yes, the 1989 Allison came from Hurricane Cosme from East Pacific. In addition, there was another tropical wave in the Gulf of Mexico, which the remnants of Cosme merged with. The 2001 Allison was over the East Pacific, but didn't develop. It did come close though.

[Ptarmigan]

The maximum 12 hour rainfall recorded was by ALERT station 1600 (Mt. Houston Rd at Greens Bayou) and was 28.3 inches. This was likely off by 2-3 inches due to the intense hourly rainfall rates and the inability of the tipping bucket to catch all the rain fall at that rate...however the official number is 28.3 in 12 hours. The same gage alose recorded 13.5 inches in 3 hours and 21.2 inches in 6 hours. The 4-day total was 38.6 inches.

ALERT station 1620 (Ley Rd at Greens Bayou) recorded 10.7 inches in 3 hours, 14.8 inches in 6 hours, 25.6 inches in 12 hours, and 33.7 inches in 4-days. A 1-hr total of 5.2 inches was recorded at this site.

The highest 1-hr total recorded was 6.3 inches at Halls Bayou and Jensen Dr.

the 1% rainfall rate based on TP 40 for Harris County is 4.8 inches, 6-hr is 8.8 inches, 12-hr is 10.5 inches.

The 28.3 inches in 12 hours is 15.7 inches above the 24-hr 1% rainfall rate of 12.6 inches.

I looked at that location in question. A little over 26 inches of rain fell in that locaiton at Mt. Houston at Greens Bayou. I know that area got a little over 28 inches of rain.
http://www.srh.noaa.gov/hgx/projects/al ... eports.htm