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Locally Heavy Rainfall in South Texas; Cool Temperatures for Much of the East

Heavy rainfall will again be possible across portions of south Texas through the weekend, which may result in additional flooding. Elsewhere, mixed precipitation is possible for the Appalachians, upper Midwest, and Great Lakes with some showers for the Gulf Coast. Temperatures will remain chilly across most of the eastern U.S., but warmer than normal weather will prevail in the West. Read More >

October 21-22nd 2017 Flooding Rains

 

An early season atmospheric river brought substantial rainfall totals to northwest Oregon and southwest Washington over the weekend of October 21-22nd 2017. It resulted in a top 10 flood for the Wilson River at Tillamook with the river cresting just above 17 ft or ~24,500 cfs.  This was the earliest in the rainy season during the past ~50 years that such a large flood had occurred at this site.  Similarly, the Grays River near Rosburg also peaked just over 15.5 ft or at ~17,000 cfs, which was also the earliest in the rainy season that such a large flood had occurred in the past ~12 years.

 

8 AM - 2 PM Saturday October 21st 2017 Composite Radar

 

A warm front lifted northeastward across the area Saturday morning, but rainfall began to pick up across the area late Saturday morning, particularly across the Coast Range where west-southwest 850mb winds strengthened into the 40-60 kt range and Integrated Vapor Transport (IVT) values pushed well over 750 kg/ms. Rainfall amounts were generally in the 0.20-0.40" range across the Willamette Valley during this time period.  Across the coast range rainfall amounts ranged between 0.50-1.80" with the highest amounts falling across Lincoln and Tillamook Counties including 1.80" at Cedar RAWS.  The lowest amounts were across the far north Oregon coast range and the Willapa Hills where ~0.50" of rain fell.

 

2 PM - 8 PM Saturday October 21st 2017 Composite Radar

 

Test

Strong west-southwesterly 850mb winds continued to enhance orographic lift and rainfall across the Cascades and Coast Range.  The main cold front can be seen starting to move southeastward towards the south Washington coast at the end of the radar loop.  Increasing lift ahead of this feature resulted in rainfall rates increasing across far northwest Oregon and southwest Washington with IVT values exceeding 1000 kg/ms.  This produced rainfall rates of 0.25-0.50" per hour for the entire period across the north Oregon Coast Range and Willapa Hills with Cedar, South Fork, Huckleberry & Abernathy RAWS all picking up over 2" of rain in the six hours.  Farther south, rainfall really backed off across Lane, Lincoln, Benton and Linn Counties during this six hour period.  Only ~0.10" fell around Eugene while PDX saw ~0.75" of rain in this six hour period.  

 

8 PM - 2 AM Sunday October 22nd 2017 Composite Radar

 

 

The lift ahead of the front, ample moisture and strong west-southwesterly 850mb winds continued to produce high rainfall rates across northwest Oregon and southwest Washington with IVT values continuing to exceed 1000 kg/ms.  The entire frontal system and atmospheric river dropped southeastward across the area between 8 pm Saturday October 21st and 2 am Sunday.  Rainfall rates peak between 1/3-2/3" per hour in this time period across the Coast Range with Abernathy RAWS in the Willapa Hills recording 0.74" between 9-10pm and Cedar RAWS measuring 0.67" between 1210-110AM Sunday.  Six hourly rainfall totals of 2.00-3.80" were recorded across the Coast Range during this time with Abernathy RAWS peaking at 3.82" in six hours ending at 11pm Saturday.  

Here is a look at the progression of IVT values and return intervals for those IVT values throughout the course of this event...

  • 5AM Saturday October 21st IVT Values & Return Intervals
  • 11AM Saturday October 21st IVT Values & Return Intervals
  • 5PM Saturday October 21st IVT Values & Return Intervals
  • 11PM Saturday October 21st IVT Values & Return Intervals
  • 5AM Sunday October 22nd IVT Values & Return Intervals

 

A number of rivers exhibited rapid rises due the rain that fell in the preceding 6-12 hours with the Grays, Nehalem, Wilson, Trask and Siletz Rivers all reaching flood stage.  You can find the corresponding hydrographs here...

 

  • Grays River at Rosburg
  • Nehalem River at Foss
  • Wilson River at Tillamook
  • Trask River at Tillamook
  • Siletz River at Siletz

 

 

2 AM - 8 AM Sunday October 22nd 2017 Composite Radar

 

The front really began to weaken during this time. Nonetheless, 1.5-2.5" fell across the Lane and Lincoln County Coast Range during this time.  

This produced a second spike in river levels across the Coast Range and Cascades.  

 

  • Siletz River
  • Alsea River
  • Siuslaw River
  • N Santiam River

 

Coastal Locations

Site 2-8am Sat 8-2pm Sat 2-8pm Sat 8-2am Sun 2-8am Sun Max 6 Hr Amt & End Time Max 12 Hr Max 24 Hr
Huckleberry 0.42" 0.49" 2.36" 1.87" 0.16" 2.71" at 10pm Saturday 4.23" 5.14"
Abernathy 0.47" 0.62" 2.77" 2.80" 0.24" 3.82" at 11pm Saturday 5.57" 6.66"
Astoria 0.28" 0.92" 1.18" 1.46" 0.01" 1.66" at 12am Sunday 2.64" 3.84"
Tidewater 0.49" 0.74" 1.77" 1.67" 0.71" 2.16" at 11pm Saturday 3.44" 4.67"
Miller 0.32" 0.56" 1.52" 1.08" 0.53" 1.52" at 8pm Saturday 2.60" 3.69"
Nehalem River Foss 0.51" 1.27" 2.42" 2.49" 0.22" 2.93" at 1245 am Sunday 4.91" 6.69"
Tillamook 0.43" 1.11" 1.35" 1.43" 0.17" 1.53" at 1am Sunday 2.78" 4.32"
Lee's Camp 1.00" 1.70" 3.10" 3.50" 0.70" 3.60" at 1am Sunday 6.60" 9.30"
South Fork 0.80" 1.47" 2.01" 2.32" 0.56" 2.33" at 3am Sunday 4.33" 6.60"
Cedar 0.63" 1.80" 2.03" 2.82" 0.50" 2.85" at 3am Sunday 4.85" 7.28"
Rye Mtn 0.95" 1.36" 1.94" 2.12" 0.99" 2.19" at 3am Sunday 4.06" 6.41"
Rockhouse 1 0.60" 0.74" 0.81" 1.36" 0.72" 1.44" at 4am Sunday 2.17" 3.63"
Gellatly 0.46" 0.73" 0.19" 0.55" 1.42" 1.60" at 6am Sunday 1.97" 2.89"
Cannibal Mtn 0.53" 1.35" 0.37" 1.49" 1.99" 2.33" at 6am Sunday 3.48" 5.20"
Wilkinson Ridge 0.37" 1.12" 0.23" 0.50" 1.44" 1.47" at 7am Sunday 1.94" 3.29"
Village Creek 0.48" 0.79" 0.44" 0.72" 1.44" 1.58" at 7am Sunday 2.16" 3.39"
Goodwin Peak 0.74" 1.56" 0.25" 0.56" 2.50" 2.50" at 7am Sunday 2.06" 3.87"
Dunes 0.50" 0.60" 0.06" 0.32" 1.33" 1.37" at 6am Sunday 1.65" 2.31"

 

 

Inland Locations

Site 2-8am Sat 8-2pm Sat 2-8pm Sat 8-2am Sun 2-8am Sun Max 6 Hr Amt & End Time Max 12 Hr Max 24 Hr
Larch Mtn 0.57" 0.76" 0.93" 1.61" 0.47" 1.72" at 3am Sunday 2.54" 3.87"
Log Creek 0.53" 1.56" 2.09" 1.52" 1.54" 2.19" at 7pm Saturday 3.65" 6.71"
Mt Hood Meadows 0.69" 1.54" 1.55" 0.85" 1.85" 1.99" at 7am Sunday 2.70" 5.79"
Middle Mtn 0.30" 0.63" 1.06" 0.98" 1.08" 1.49" at 6am Sunday 2.06" 3.75"
Wanderer's Peak 0.21" 1.72" 0.56" 0.57" 1.83" 1.86" at 7am Sunday 2.40" 4.68"
Horse Creek 0.28" 0.65" 0.59" 1.07" 1.47" 1.67" at 7am Sunday 2.54" 3.78"
Yellowstone Mtn 0.61" 1.76" 0.64" 1.21" 2.06" 2.20" at 7am Sunday 3.27" 5.67"
Boulder Creek 0.41" 1.52" 0.70" 0.38" 1.43" 1.61" at 3pm Sunday 2.22" 4.03"

 

The Time Delay Between Peak River Flows versus 6 Hour Rainfall

 

Name Time of First Peak Flow

RAWS Site

Time of Max 6 Hour Rain

Time Delay Hours

Time of Max 3 Hour Rain Time Delay Hours
Willapa River 5AM Sunday Huckleberry 10 PM Saturday 7 8-10 PM Saturday 7-9
Naselle River 130AM Sunday Huckleberry 10 PM Saturday 3.5 8-10 PM Saturday 3.5-5.5
Grays River 230 AM Sunday Huckleberry & Abernathy                10 PM Saturday                & 11 PM Saturday    3.5 &   4.5 8-10 PM Saturday & 11 PM Saturday

4.5/6.5 & 3.5

Nehalem River at Vernonia 530 AM Sunday Miller &  Tidewater                 8 PM Saturday                  & 11 PM Saturday    9.5 &   6.5

9 PM Saturday & 12 AM Sunday

 8.5 &  5.5
Nehalem River at Foss 330 AM Sunday Nehalem River & Lees Camp             1245 AM Sunday               & 1 AM Sunday    2.5 &     2.75 1245 AM & 1 AM 2.5 & 2.75
Wilson River  430 AM Sunday Lees Camp & South Fork                1 AM Sunday                  & 3 AM Sunday   3.5 &     1.5/3.5 1 AM Sunday  3.5
Trask River  430 AM Sunday Lees Camp & South Fork                1 AM Sunday                   & 3 AM Sunday   3.5 &     1.5/3.5 1 AM Sunday 3.5
Nestucca River  530 AM Sunday Cedar 3 AM Sunday 2.5 2 AM Sunday 3.5
Siletz River 830 AM Sunday Rockhouse & Gellatly                   4 AM Sunday                 & 6 AM Sunday   4.5 &   2.5    2 AM Sunday &     5 AM Sunday  6.5 &  3.5
Alsea River 1230 PM Sunday Cannibal Mtn & Wilkinson                 6 AM Sunday                     & 7 AM Sunday  6.5 & 5.5 5-7AM Sunday 5.5 - 7.5
Siuslaw River 1130 AM Sunday Goodwin Peak 7-8 AM Sunday 4.5-5.5 5-7 AM Sunday 4.5-6.5
Sandy River 1030 AM Sunday Log Creek 5-6 AM Sunday 4.5-5.5 5-6 AM Sunday 4.5-5.5
Clackamas River at Estacada 1030 AM Sunday Wanderers Peak 7 AM Sunday 3.5 6-7 AM Sunday 3.5-4.5
Clackamas River at Oregon City 3 PM Sunday Wanderers Peak 7 AM Sunday 8 6-7 AM Sunday 8-9
Tualatin River at Dilley 11 PM Sunday Rye Mtn 3 AM Sunday 20 2 AM Sunday 21
Luckiamute River 4 AM Monday Rockhouse & Gellatly                4 AM Sunday                     & 6 AM Sunday 24-26    2 AM Sunday &     5 AM Sunday 23-26
Mary's River 2 PM Sunday Gellatly 6 AM Sunday 8 5 AM Sunday 9
N Santiam River at Mehama 10 AM Sunday Boulder Creek 8-9 AM Sunday 1-2 7-8 AM Sunday 2-3
McKenzie River at Vida 2pm Sunday Trout Creek 10 AM Sunday 4 8 AM Sunday 6
Mohawk River 5pm Sunday Brush Creek 9 AM Sunday 8 7 AM Sunday 10


 

Email Colby at w-pqr.webmaster@noaa.gov for comments or questions.