Hydrologic Applicationof the

Tropical Cyclone Precipitation Climatology

PAMS Mini-Technical ConferenceMarch 15, 2005

Jason Caldwell, HAS ForecasterLower Mississippi River Forecast Center

Slidell, LA

Gloria Forthun, Regional ClimatologistSoutheast Regional Climate Center

Columbia, SC

Provide river and flood forecasts and warnings for the protection of lives and property.

Provide basic hydrologic forecast information for the nation’s environmental and economic well being.

National Weather ServiceHydrologic Services Program Mission

Hydrologic Services Program

RIVER FORECAST CENTERS (RFCs) Strong Technical Support/Focus Calibrates/Maintains/Executes Hydrologic Forecast Models Works directly with some sophisticated water users

(e.g., USACE, USGS, DWR, etc.)

WEATHER FORECAST OFFICES (WFOs) Uses/Tailors RFC Forecasts/Services to Local Users River/Flood Forecast Watch/Warning Program Delivers Products/Services to the Local Media/Public

Two Main RFC Functions Operations

Flood/River Forecasting Dam Break Support Flash Flood Support Snowmelt Forecasting Water Supply Forecasting Precipitation Forecasting Data QC

Procedure Development Model Calibration Model Maintenance/Support Special Studies

forecastprecip / temp

Operational Flood Forecasting

HAS

RiverForecastSystem

parameters

ObservingSystems

data

Calibration

modelguidance

Hydrologist

hydrologicexpertise &judgment

bulletinsgraphics

Flood ForecastGuidance

LMRFC AREA OF RESPONSIBILITY

• 2900+ River/Precipitation Gage Network

• 220 Forecast Points (189 Daily, 31 Flood-only)

• Weekly 28-day Forecasts at 10 Locations

Servicing18 WFOs

RNK GSPFFC MRXBNA HUNMEM PAHLSX SGFLIT JANTSA SHVLIX MOBFWD LCH

WEB-BASED PRODUCTS OF THE RFC

PRECIPITATION

FLOODING

http://www.srh.noaa.gov/lmrfc

EXPANSION OF THE TROPICAL CYCLONE-INDUCED PRECIPITATION

CLIMATOLOGY

-ALL tropical cyclone landfalls from TX/Mexico border to Chincoteague, VA (TX,LA,AR,MS,AL,TN,NC,SC,VA,FL)

-Period of record from 1971-2000

-Storm characteristics include: State(s) affected, direction of motion, speed of motion, storm intensity, and, potentially, synoptic interaction

-Potential application to QPF and RVF at NWS WFOs and RFCs

-WAAAYYY in the future……..a web- based application to develop the plots dynamically from the database

CLIMATOLOGICAL PRECIPITATION DATA

INTERPOLATE TO GRIDDED DATA USING GIS

GRID STATISTICS TO PRODUCE BASIN MAP

USE HPC AND NHC FORECASTS TO

DETERMINE START TIME

TIME DISTRIBUTE THE DATA INTO 6HR VALUES

CAVEATS

-USED DAILY DATA TO COMPUTE STORM TOTAL PRECIPITATION

-ONLY USED STATIONS WITH100%; VARY BY STORM

-ASSUMED T-DISTRIBUTION USING FEW HOURLY SITES

-PRECIPITATION TIMING BASED ON FORECASTS W/ ERRORS

DATA COLLECTION AND CLIMO QPF

0000UTC 29 AUGUST 2005

1200UTC 30 AUGUST 2005

HURRICANE KATRINA CASE STUDY

MISSISSIPPI MAJOR HURRICANES 1971-2000

Andrew August 26-28, 1992Carmen September 7-9, 1974Opal October 4-5, 1995Frederic September 12-14, 1979Eloise September 22-24, 1975Elena September 2-4, 1985

SITE SELECTION

142 140 136130 126 128

94

0

20

40

60

80

100

120

140

160

CO

UN

T

Ca

rme

n7

4

Elo

ise

75

Fre

de

ric7

9

Ele

na

85

An

dre

w9

2

Op

al9

5

Ka

trin

a0

5

STORM

AVAILABLE SITES BY STORM

•361 Observation Sites Available

•Approximately 40% with 100% data

BIG BLACK FORECAST GROUP

MODELED BASINS

Kilmichael S Big Black

West F Big Black

Goodman S Big Black

Way St/Hwy 16 S Big Black

Bentonia F Big Black

Bovina F Big Black

Willows H Bayou Pierre

Eddiceton S Homochitto

Rosetta F Homochitto

Woodville H Buffalo

F Forecast PointS Support PointH Headwater

PERFORMING A CONTINGENCY FORECAST

MAXIMUM PRECIPITATION PLOT INDICATED 2-6” ACROSS BIG BLACK FORECAST GROUP

USED 72 QPF FROM HPC/LMRFC AND CLIMO MAX IN HYDROLOGIC MODELS

USED 8/27 12UTC AS A STARTING POINT FOR FORECAST TO INCREASE LEAD TIME OF POTENTIAL RIVER FLOODING

FIRST MUST TIME DISTRIBUTE THE MAX CLIMO PRECIPITATION FOR USE IN THE MODELS

HOURLY PRECIPITATION CLIMATOLOGY FOR MAJOR HURRICANES

AT JACKSON, MS

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

1 13 25 37 49 61

HOUR

PR

EC

IP (

IN.)

carmen andrew eloise frederick Total

TIME-DISTRIBUTED PRECIPITATION AT JACKSON, MS

15%

7%

18%

41%

10%

5%

1% 1% 1% 1%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

F06 F12 F18 F24 F30 F36 F42 F48 F54 F60

FORECAST HOUR

PE

RC

EN

T O

F S

TO

RM

TO

TA

L

TIME-DISTRIBUTION OF FMAP BIG BLACK FORECAST POINTS 8/27@12UTC

0

0.5

1

1.5

2

2.5

3

F42 F48 F54 F60 F66 F72

FORECAST HOUR

PR

EC

IP (

IN.)

WSTM6-OP

BTAM6-OP

BOVM6-OP

RSAM6-OP

WSTM6-MAX

BTAM6-MAX

BOVM6-MAX

RSAM6-MAX

NHC Forecast placed Katrina approx. 250NM from Big Black Forecast Group by 2AM 8/29

HPC/LMRFC QPF began at F42 from 8/27 12UTC grids

Correlated to first 6-hour period ending 1AM 8/29

THE TIMING ISSUE

FMAP VS. OBSERVATIONSBIG BLACK FORECAST GROUP

0

1

2

3

4

5

6

7

KILM6 WSTM6 GOOM6 BBWM6 BTAM6 BOVM6 WBPM6 EDDM6 RSAM6 WOOM6

BASINS

PR

EC

IP (

IN.) 8/27 QPF

8/28 QPF

MAXQPF

KATRINA

WHAT TO EXPECT FROM THE FORECASTS?

MAX UNDER-PREDICTED ACROSS UPPER BIG BLACK FORECAST GROUP; OVER-PREDICTED LOWER

HPC/LMRFC QPF PERFORMED WELL UPPER BIG BLACK; UNDER IN LOWER

MAX PRODUCED HIGHEST QPF EARLIER THAN HPC/LMRFC WITH LESS SPREAD

SO……WHAT DOES THIS MEAN?

EXPECT BEST PERFORMANCE BY HPC/LMRFC IN BIG BLACK, BETTER PERFORMANCE ACROSS HOMOCHITTO BY MAX

MAX27

OBS

OP27

CREST*=14.77am 9/1

CREST=16.6 7am 9/1

CREST=17.0 noon 9/1

WEST, MS

FORECASTFROM8/27 @ 12UTC

*

*Still rising, not actual crest

OBS=16.8 at 7am 9/1

BENTONIA, MS

FORECASTFROM8/27 @ 12UTC

MAX27

OBS

OP27

CREST=13.5 7pm 8/30

CREST=16.0* 7am 9/1

CREST=19.5 7pm 8/31

*Still rising, not actual crest

OBS=19.4 at 7am 9/1

BOVINA, MS

FORECASTFROM8/27 @ 12UTC

MAX27

OBS

OP27

CREST*=13.5 7am 9/1

CREST*=13.0 7am 9/1

CREST=25.0 7pm 8/30

*Still rising, not actual crest

OBS=22.8 at 7am 9/1

ROSETTA, MS

FORECASTFROM8/27 @ 12UTC

MAX27

OBS

OP27

CREST=8.2 7am 8/30

CREST=8.2 7pm 8/30

CREST=5.4 7am 8/30CREST=5.6

7am 8/31

BIG BLACK FORECAST CREST* VS. OBS

0.0

5.0

10.0

15.0

20.0

25.0

30.0

KILM6 WSTM6 GOOM6 BBWM6 BTAM6 BOVM6 WBPM6 EDDM6 RSAM6 WOOM6

BASIN

HG

(F

T.)

MAX27

MAX28

OP27

OP28

OBSV

MAX Under-Estimated Gage Heights

MAX Performed Well Lower Forecast

Group

CONCLUSIONS• MAX under-predicted precipitation in Big Black, over-predicted in Homochitto

• HPC/LMRFC did good job in Big Black, under-predicted in Homochitto

• As a result, HPC/LMRFC river forecasts better across Big Black with best results from MAX in Homochitto

• Need to expand climatology to include similar track and speed storms regardless of intensity

• For contingency purposes in Katrina, climatology would have been safe bet for using 72 hours of QPF in forecast models without exceeding observed crests

HOWEVER…..

A contingency forecast should give a “worst-case” scenario given the current hydrometeorological conditions……

MAX FAILED AT THIS TASK ACROSS THE BIG BLACK

ACKNOWLEDGMENTS

Southeast Regional Climate CenterGloria Forthun, Justin Glenn, Andy Brandenburg, and Michael Johnson

South Carolina State Climatology Office

National Climatic Data Center

Dave Brandon, CBRFC

Dave Reed, LMRFC

END OF SLIDE SHOW, ADDITIONAL SLIDES

FOLLOW

MAX27 MAX28

OP27 OP28

OBS

WBPM6

MAX27 MAX28

OP27 OP28

OBS

RSAM6

MAX27 MAX28

OP27 OP28

OBS

EDDM6

MAX27 MAX28

OP27 OP28

OBS

WOOM6

QPF 8/27/06 VS. MAX CLIMO

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

KILM6 WSTM6 BTAM6 BOVM6 WBPM6 EDDM6 RSAM6 WOOM6

FORECAST BASIN

PR

EC

IP E

RR

OR

(IN

.)

8/27 12z

MAX

MAX27 MAX28

OP27 OP28

OBS

WSTM6

MAX27 MAX28

OP27 OP28

OBS

BTAM6

MAX27 MAX28

OP27 OP28

OBS

BOVM6