1 AMBER Areal Mean Basin Estimated Rainfall COMAP Symposium 00-3 Robert S. Davis, Pittsburgh WFO Presented by Tom Filiaggi

1

AMBER

Areal Mean Basin Estimated RainfallAreal Mean Basin Estimated Rainfall

COMAP Symposium 00-3COMAP Symposium 00-3

Robert S. Davis, Pittsburgh WFORobert S. Davis, Pittsburgh WFOPresented by Tom FiliaggiPresented by Tom Filiaggi

2

AMBER OverviewAMBER Overview

• All watersheds in county warning area are All watersheds in county warning area are defined to a Minimum Basin Area (MBA) of 2 midefined to a Minimum Basin Area (MBA) of 2 mi22 to show spatial rainfall distribution. to show spatial rainfall distribution.

• The WSR-88D polar grid (1The WSR-88D polar grid (1oo by 1km) is mapped by 1km) is mapped to the defined watersheds.to the defined watersheds.

• Average Basin Rainfall (ABR) is computed for Average Basin Rainfall (ABR) is computed for each watershed every volume scan. each watershed every volume scan.

• An hourly ABR rate is determined from the single An hourly ABR rate is determined from the single volume scan (5-6 min.) of ABR.volume scan (5-6 min.) of ABR.

3

National Basin DelineationNational Basin Delineation

• 30Sep1999 – NWS agrees to fund the 30Sep1999 – NWS agrees to fund the AMBER National Basin Delineation project AMBER National Basin Delineation project by NSSL for all of the United States.by NSSL for all of the United States.

• ArcInfo used to define the watershed ArcInfo used to define the watershed boundaries.boundaries.

• USGS 1 arc second (30 m) DEM data USGS 1 arc second (30 m) DEM data supplied by EROS Data Center.supplied by EROS Data Center.

• www.nssl.noaa.gov/teams/western/basinswww.nssl.noaa.gov/teams/western/basins

4

5

6

7

8

AMBER Watershed DivisionAMBER Watershed Division

• All watersheds in the county warning area All watersheds in the county warning area are divided into hydrologic segments no are divided into hydrologic segments no larger than 10 milarger than 10 mi22..

• A Minimum Basin Area of 2 miA Minimum Basin Area of 2 mi22 is used in is used in the initial NSSL stream creation procedure.the initial NSSL stream creation procedure.

• Each forecast office may modify the NSSL Each forecast office may modify the NSSL stream database (subdivide or aggregate).stream database (subdivide or aggregate).

9

AMBER 10 miAMBER 10 mi22 Watersheds Watersheds

• Operational 01May1985Operational 01May1985• Basins defined on “Fishing stream map of Basins defined on “Fishing stream map of

Pennsylvania. Pennsylvania. • Color Graphics display of WSR-57 rainfall Color Graphics display of WSR-57 rainfall

estimates RADAP-II data (2estimates RADAP-II data (2oo x 1 nm grid) x 1 nm grid)• 36 county map backgrounds with overlay of 36 county map backgrounds with overlay of

defined streams watersheds.defined streams watersheds.• No ABR computation.No ABR computation.

10

Pine Creek Flash FloodMay 30, 1986

AlleghenyRiverEtna

AllisonPark

#1061Area 68mi2

Min/Max AZRAN

044° at 11km101° at 27km

Pine Creek

PBZ WSR-88D

11


AlleghenyRiverEtna

AllisonPark

#1061Area 68mi2

Min/Max AZRAN

044° at 11km101° at 27km

Pine Creek

PBZ WSR-88D2"

4"6"

12


AlleghenyRiver

#1061

Area 68mi2

Pine Creek

5174

5173 5172 5171

5170

5167

5169

5168

13.9mi2

10.1mi2 5.5mi24.3mi2

3.7mi2

4.1mi2

6.2mi28.3mi2

5167 Little Pine Creek5168 Little Pine Creek5169 Gourdhead Run5170 Crouse Run5171 Willow Run5172 Montour Run5173 North Fork Pine Creek5174 Headwaters Pine Creek

0 4km

13

2"

4"6"


AlleghenyRiver

#1061

Area 68mi2

Pine Creek

5174

5173 5172 5171

5170

5167

5169

5168

13.9mi2

10.1mi2 5.5mi24.3mi2

3.7mi2

4.1mi2

6.2mi28.3mi2


0 4km

14

Little Pine Creek Stage (ft)Little Pine Creek Stage (ft)30May1986 (UTC)30May1986 (UTC)

0

2

4

6

8

10

12

19

00

19

30

20

00

20

30

21

00

21

30

22

00

22

30

23

00

Stream Gage

15


AlleghenyRiver

#1061

Area 68mi2

Pine Creek

5174

5173 5172 5171

5170

5167

5169

5168

13.9mi2

10.1mi2 5.5mi24.3mi2

3.7mi2

4.1mi2

6.2mi28.3mi2


5175-5177 Local

5175

5176

51770 4km

16

DHR WSR-88D Bin AssignmentDHR WSR-88D Bin AssignmentPolar grid 1Polar grid 1oo by 1km by 1km

• DHR grid is mapped to all defined DHR grid is mapped to all defined watershed segments. This allows ABR watershed segments. This allows ABR computation in 5-6 minute time steps.computation in 5-6 minute time steps.

• DHR grid is mapped to all defined Urban DHR grid is mapped to all defined Urban Areas to compute ABR urban rainfall. Areas to compute ABR urban rainfall.

• Single 1km DHR bins are assigned to Single 1km DHR bins are assigned to location of all rain gages, allowing gage location of all rain gages, allowing gage comparison with radar estimated rainfall.comparison with radar estimated rainfall.

17

78°

80°

82°

84°

86°

88°

90°

92°

94°

96°

22.5km

24.5km26.5km

6380

6379

6378

LITTLE PINE CREEK #5168

2.4mi2

2.1mi2

1.6mi2

ABR 1930-2100 UTC

6380:7.09in

6379:6.35in

6378:3.55in

5168:5.70

30May1986RADAP-II

18

50km 51km 52km 53km

1km 1km 1km90°

91°

0.34mi2 0.35mi2 0.35mi2

0.8

7km

0.9

3km

0.35"0.25"0.08"

(.34 + .35 + .35)

6min RAIN:Z = 300R1.4

ABR = = 0.228"

watershedboundary

AVERAGE BASIN RAINFALL (ABR)

Rate = 0.228 X 10 = 2.28 in/hr

.34 .35 .35 .35 )(.08 x x x+ .25 +

42dBZ* 50dBZ* 52dBZ** Average Reflectivity 2 Scans

19

Pine Creek AftermathPine Creek Aftermath

• RADAP-II provided excellent rainfall RADAP-II provided excellent rainfall estimates for bucket survey gages and for estimates for bucket survey gages and for ABR in watersheds down to 3miABR in watersheds down to 3mi2 2 ..

• Disaster survey team recommended that a Disaster survey team recommended that a 1-hour flash flood guidance (FFG) be 1-hour flash flood guidance (FFG) be initiated.initiated.

• Analysis of flash flood watersheds needed Analysis of flash flood watersheds needed to be reduced from 10 mito be reduced from 10 mi22 to at least 3mi to at least 3mi22..

20

AMBER 3 mi2 Watersheds

• Operational 01May1990 (RADAP-II data)Operational 01May1990 (RADAP-II data)• MBR and ABR computations.MBR and ABR computations.• 01June1993 WSR-88D Installed.01June1993 WSR-88D Installed.• Operational 01May1996 (WSR-88D data)Operational 01May1996 (WSR-88D data)• Watershed analysis accomplished on 7.5 Watershed analysis accomplished on 7.5

minute topographic maps and MBA minute topographic maps and MBA reduced to 3 mireduced to 3 mi22. .

• ABR computations only.ABR computations only.

21

Flash Flood Threat and ABRFlash Flood Threat and ABR

• Severity of flash flooding is directly related Severity of flash flooding is directly related to the observed ABR in a watershed.to the observed ABR in a watershed.

• The time period of the ABR determines the The time period of the ABR determines the ABR rate. The higher the ABR rate, the ABR rate. The higher the ABR rate, the greater the risk of serious flash flooding.greater the risk of serious flash flooding.

• ABR varies as function of watershed area. ABR varies as function of watershed area. As watershed area increases, ABR and As watershed area increases, ABR and ABR rate tend to decrease.ABR rate tend to decrease.

22

FF Scale for Flash FloodingFF Scale for Flash FloodingABR in inchesABR in inches

• FF0 ABR = FFG to < FFG + 0.5FF0 ABR = FFG to < FFG + 0.5

• FF1 ABR = FFG + 0.5 to < FFG + 1.5FF1 ABR = FFG + 0.5 to < FFG + 1.5

• FF2 ABR = FFG + 1.5 to < FFG + 2.5 FF2 ABR = FFG + 1.5 to < FFG + 2.5



• FF5 ABR = FFG + 4.5 to < FFG + 5.5FF5 ABR = FFG + 4.5 to < FFG + 5.5

• FF6 ABR = FFG + 5.5 or higher.FF6 ABR = FFG + 5.5 or higher.

23

ABR RateABR Rate

• Based on 5-6 minute observed ABR. Based on 5-6 minute observed ABR.

• Hourly ABR Rate = ABR x 3600/vsec, Hourly ABR Rate = ABR x 3600/vsec, where vsec= the number of seconds in the where vsec= the number of seconds in the volume scan.volume scan.

• ABR Rate is used to identify watersheds ABR Rate is used to identify watersheds currently receiving the heaviest rainfall, currently receiving the heaviest rainfall, before the flash flood producing before the flash flood producing accumulation occurs.accumulation occurs.

24

AMBER Z/R Gage ComparisonAMBER Z/R Gage Comparison

• The single 1km DHR bin that contains the The single 1km DHR bin that contains the rain gage is used to compute the radar rain gage is used to compute the radar rainfall estimate.rainfall estimate.

• Tropical vs. Standard Z/R usage can be Tropical vs. Standard Z/R usage can be estimated using 15 minute gage data.estimated using 15 minute gage data.

• Gage comparisons should be done to verify Gage comparisons should be done to verify validity of the WSR-88D rainfall estimates.validity of the WSR-88D rainfall estimates.

25

Pitcairn, PA Flash FloodPitcairn, PA Flash Flood

01-02July199701-02July1997

26

TURTLE CREEK

N

0 10km

M.A.P. RAIN GAGES

BRADDOCK M.A.P.WATERSHED BOUNDARY

24-HOUR RAINFALLENDING 1200 UTC02JULY1997

0.29

0.32

0.92

1.71 3.76

0.05

1.380.35

0.23

0.07

446mi2

147mi2

(in)

PITCAIRN

ALLEGHENYCOUNTY

WASHINGTONCOUNTY

WESTMORELANDCOUNTY

CITY OF PITCAIRN

27

AVERAGE BASIN RAINFALL (ABR)TURTLE CREEK WATERSHED 147mi2

01-02JUL1997

01/2200-

02/0015 UTC

X.XX = ABR (in)

MONONGAHELARIVER

ALLEGHENYCOUNTY

WESTMORELANDCOUNTY

N

PITCAIRN

0 5km

1108 2303 2306

2307

2304 2305

1.21 1.73 0.740.12

0.41 0.16

1108 = TURTLE CREEK(1)2303 = TURTLE CREEK(2)2304 = BRUSH CREEK(1)

2305 = BRUSH CREEK(2)2306 = TURTLE CREEK(3)

2307 = TURTLE CREEK(4)

0.76

24.0mi2

10.2mi228.2mi2

22.4mi2 34.8mi2

26.9mi2

28

5328

5323

TURTLE CREEK

I-76

I-76

PA-22

PA-22

4229

4149

PITCAIRN

ROADS

WATERSHEDBOUNDARY

3km

5328 = ABER'S CREEK 10.4mi25323 = DIRTY CAMP RUN 3.3mi2

4149 = GATEWAY MIDDLE SCHOOL

4229 = HOLIDAY PARK IFLOWS

MURRYSVILLE

AVERAGE BASIN RAINFALL (ABR)

01-02JUL1997 01/2200 - 02/0015 UTC

(x.xx) = ABR (in) (1.49)

(2.64)

0

N

29

TURTLECREEK

MURRYSVILLE

#6308

#6307

#6306

HOLIDAY PARK IFLOWS#4229

GATEWAY MIDDLESCHOOL #4149

ABER'S CREEK #5328ABER'S CREEK SUBDIVISIONS

6306 = THOMPSON RUN

6307 = PIERSON'S RUN

6308 = HEADWATERS OF ABER'S CREEK

10.4mi2

4.7mi2

1.9mi2

2.4mi2

I-76

I-76

(1.49)

(3.21)

(1.68)

(0.39)

0 3km

AVERAGE BASIN RAINFALL (ABR)01-02JUL1997 01/2200 - 02/0000 UTC

(x.xx) = ABR (in)

PA-22

PA-22

3.30 in.

1.26 in.

N

39-44km FROMKPBZ WSR-88D

30

Aber’s Creek #5328Aber’s Creek #532801July1997 10.8mi01July1997 10.8mi22

00.20.40.60.8

11.21.41.61.8

2

2159

2211

2223

2234

2246

2258

2310

2321

2333

2345

2357

ABR Rate

ABR

1hr FFG

31

Thompson Run #6306Thompson Run #630601July1997 2.4mi01July1997 2.4mi22

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

2159

2211

2223

2234

2246

2258

2310

2321

2333

2345

2357

ABR Rate

ABR

1hr FFG

32

Thompson Run FloodingThompson Run Flooding

• Three feet of water was reported on Route Three feet of water was reported on Route 22 near the outflow of Thompson Run into 22 near the outflow of Thompson Run into Aber’s Creek at 2320UTC.Aber’s Creek at 2320UTC.

• Route 22 is the main parkway through the Route 22 is the main parkway through the eastern suburbs of Pittsburgh. eastern suburbs of Pittsburgh.

• The road was closed for almost an hour due The road was closed for almost an hour due to the high water. to the high water.

33

TURTLECREEK

PITCAIRN

3.3 mi2

1.5 mi2

1.8 mi2

DIRTY CAMP RUN

DIRTY CAMP RUN(2)

#5323

#6305

#6304

DIRTY CAMPRUN(1)

ELEMENTARYSCHOOL

(x.xx) = ABR (in)

(1.97)

(3.16)

(2.64)

0 2km

N

38-41km FROMPBZ WSR-88D

01-02July199601/2200 -02/0015 UTC

34

Dirty Camp Run #5323Dirty Camp Run #532301July1997 3.3mi01July1997 3.3mi22

0

0.5

1

1.5

2

2.5

3

2159

2211

2223

2234

2246

2258

2310

2321

2333

2345

2357

ABR RateABR1hr FFG

35

Dirty Camp Run(2) #6305Dirty Camp Run(2) #630501July1997 1.5mi01July1997 1.5mi22

0

0.5

1

1.5

2

2.5

3

3.5

4

2159

2211

2223

2234

2246

2258

2310

2321

2333

2345

2357

ABR RateABR1hr FFG

36

Dirty Camp Run(1) #6304Dirty Camp Run(1) #630401July1997 1.8mi01July1997 1.8mi22

0

0.5

1

1.5

2

2.5

2159

2211

2223

2234

2246

2258

2310

2321

2333

2345

2357

ABR RateABR1hr FFG

37

Dirty Camp Run(1-2) #6304/5Dirty Camp Run(1-2) #6304/501July1997 ABR Rates01July1997 ABR Rates

0

0.5

1

1.5

2

2.5

3

3.5

4

2159

2211

2223

2234

2246

2258

2310

2321

2333

2345

2357

DC(1)RateDC(2) Rate

38

39

40

Pitcairn Flash FloodingPitcairn Flash Flooding

• About 10 million dollars of flood damage About 10 million dollars of flood damage occurred in the city of Pitcairn. occurred in the city of Pitcairn.

• Residents in Pitcairn reported that Dirty Residents in Pitcairn reported that Dirty Camp Run was up near bankfull before the Camp Run was up near bankfull before the heavy rain began in town.heavy rain began in town.

• The peak of the flooding in Pitcairn The peak of the flooding in Pitcairn occurred from 01July/2330 UTC to occurred from 01July/2330 UTC to 02July/0030 UTC.02July/0030 UTC.

41

Tropical Z/R CasesTropical Z/R Cases

• Standard Z/R: Z = 300RStandard Z/R: Z = 300R1.41.4

• Tropical Z/R: Z = 250RTropical Z/R: Z = 250R1.21.2

• Maximum Rate Cap 5.0 in/hr?Maximum Rate Cap 5.0 in/hr?

• Tropical Storm not required!!!Tropical Storm not required!!!

42

Standard and Tropical Z/RStandard and Tropical Z/R

0

1

2

3

4

5

6

7

835 38 41 44 47 50 53 56

Z=300R1.4

Z=250R1.2

43

ConclusionsConclusions

• Small watersheds definition is the key to Small watersheds definition is the key to detection of flash flooding.detection of flash flooding.

• ABR Rate gives early warning for flash ABR Rate gives early warning for flash flood potential. flood potential.

• Time duration of rainfall display impacts Time duration of rainfall display impacts forecaster perception of flash flood threat.forecaster perception of flash flood threat.

• User selectable time window needed.User selectable time window needed.

44

AMBER SummaryAMBER Summary

• ABR provides basin specific rainfall to ABR provides basin specific rainfall to determine flash flood risk (ABR-FFG)determine flash flood risk (ABR-FFG)

• ABR rate focuses forecaster attention on ABR rate focuses forecaster attention on critical streams before flooding occurs.critical streams before flooding occurs.

• History of ABR helpful in adjusting FFG for History of ABR helpful in adjusting FFG for multiple rainfall events.multiple rainfall events.

• Basin specific ABR allows forecaster to Basin specific ABR allows forecaster to mention “threat area” in warning text.mention “threat area” in warning text.

45

AMBER Data Sources

• ArcView and the spatial analyst extension. ArcView and the spatial analyst extension. www.esri.comwww.esri.com

• USGS Data (3 arc second DEM data) USGS Data (3 arc second DEM data) edcwww.cr.usgs.govedcwww.cr.usgs.gov

• EPA Data (RF3 data files) EPA Data (RF3 data files) www.epa.gov/OST/BASINS/gisdata.htmlwww.epa.gov/OST/BASINS/gisdata.html

• Ami Arthur [email protected] Arthur [email protected]• [email protected] (SOO KHNL)[email protected] (SOO KHNL)

46

AMBER Case Studiesftp 198.206.50.10 public

• buff.ppt 13Jul96 buff.ppt 13Jul96 • epgh99.ppt 18May99epgh99.ppt 18May99• pitcairn.ppt 01Jul97pitcairn.ppt 01Jul97• zion.ppt 27Jul98zion.ppt 27Jul98• ohio98.ppt 26Jun98ohio98.ppt 26Jun98• dallas95.ppt 05May95dallas95.ppt 05May95• ftc97.ppt 28Jul97ftc97.ppt 28Jul97• kc1998.ppt 04Oct98kc1998.ppt 04Oct98

• Buffalo Creek, COBuffalo Creek, CO• Pittsburgh, PAPittsburgh, PA• Pittsburgh, PAPittsburgh, PA• Cedar City, UTCedar City, UT• Eastern OhioEastern Ohio• Dallas, TXDallas, TX• Fort Collins, COFort Collins, CO• Kansas City, MOKansas City, MO

Documents

1 AMBER Areal Mean Basin Estimated Rainfall COMAP Symposium 00-3 Robert S. Davis, Pittsburgh WFO Presented by Tom Filiaggi