hydrologic application of the tropical cyclone precipitation climatology pams mini-technical...
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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
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