Short-Term Climate Forecasting: Process and Products David Miskus NOAA/NWS/NCEP/Climate Prediction Center Technical Workshop on Drought & Seasonal Forecasting Tools Wednesday, December 6, 2017, 9:00am 3:30pm J.J. Pickle Research Campus, Advanced Computing Building #205, TACC Training Room #1.104 Austin, TX 1
CPC Mission Deliver real-time products and information that predict and describe climate variations on timescales from weeks to year(s) thereby promoting effective management of climate risk and a climate-resilient society. Focus: weeks, months, seasons, years (i.e. short term climate) Integral to NWS Seamless Suite of Products Valuable resource for NOAA s efforts to deliver climate services Provides strong name recognition in international efforts Temperature Outlook
N A T I O N A L O C E A N I C A N D A T M O S P H E R I C A D M I N I S T R A T I O N NOAA Seamless Suite of Forecast Products Spanning Climate and Weather Click to edit Master title style Service Center Perspective Climate Outlooks Climate Predictions Weather Forecasts Warnings Forecast Lead Time Hours Minutes Days 1 week 2 weeks SPC Months HPC Seasons OPC AWC CPC TPC SWPC Years Collaborative Forecasts Forecast Uncertainty Climate/Weather Linkage Impact-Based Decision Support RECOVERY RESPONSE PREPARATION NWS_041 3 3
Climate Prediction Products Focus on Week-2 to Seasonal-to-Interannual o o o o o o o o o 6-10 Day & 8-14 Day [ERFs] Precipitation & Temperature Outlooks Day 3-14 Hazards Outlooks (US [HAF], Global Tropics [MJO/GTH]) Monthly & Seasonal [LLFs] Precipitation & Temperature Outlooks Monthly & Seasonal Drought Outlooks [DOs] Seasonal Hurricane Outlooks (Atlantic and Eastern Pacific) Monthly ENSO Prediction Week 3-4 Temperature/ Precipitation Week 2 Heat Outlook Arctic Sea Ice Forecasts * Dynamical Models Climate Forecast System Global Forecast System ECMWF NMME
Production Schedule ERF 7 days a week; HAF Mon-Fri; MJO/GTH Weekly (Tue), during Summer (Tue & Fri); WK34 Weekly (Fri); Monthly LLF Twice per month (3 rd Thu & update last day of month); Seasonal LLF Monthly (3 rd Thu); --- Degree Day outlooks, POE; Seasonal DO Monthly (3 rd Thu); Monthly DO Monthly, last day of month; ENSO Weekly; Hurricane Outlook Yearly (with 1 update)
Forecast Process Schematic Upper-Air Multiple Dynamical model forecasts Surface Multiple Dynamical model forecasts Subjective weighted average 500-hPa height and anomaly forecast (BLEND). Observations Verifications/Statistical tools Downscaling, Analogs, Composites, Calibrations, Consolidation Create surface temperature and precipitation tools using BLEND input. Subjective formulation of the probability of temperature and precipitation tercile categories. Write the forecast bulletin, NMCPMDMRD - FXUS06 KWBC. Dissemination to public between 3-4 PM Eastern Time
DYNAMICAL MODELS Forecast tools Global Forecast System (GFS) and ensembles European Centre for Medium-range Weather Forecasts (ECMWF) ensembles Canadian ensembles STATISTICAL TOOLS (Downscaling) GEFS/ECWMF T, P bias corrected/calibrated, using reforecasts NAEFS Bias-corrected ensemble forecasts T, P Consolidation GEFS and ECMWF Dynamic weighting of calib models GFS P, T Dynamical model output calibrated P, T Analog composites Average T, P for the 10 best 500-hPa analogs Klein T screening regression Tele-connections Simultaneous, significant temporal correlations for two or more widely separated locations.
Where does seasonal predictability come from? Persistent or recurring atmospheric circulation patterns associated with anomalies in the initial state of the climate system, or boundary conditions El Niño and La Niña: anomalous climate states whose development, persistence and evolution are somewhat understood Potentially persistent or recurring atmospheric circulation patterns that are less well understood: AO, NAO, PNA Unidentified persistent atmospheric patterns may arise from the initial state of the climate system or from boundary forcing Decadal variability or trends: 1. Climate Change 2. Anomalies in the large scale ocean circulation can vary over decadal timescales e.g. Atlantic Meridional Overturning (AMOC) 8
FACTORS INFLUENCING A Climate Change - trends CLIMATE FORECAST Natural Climate Variability organizes weather El Niño-Southern Oscillation (ENSO) Mid-latitude Oscillation modes (NAO, AO, PNA, ) Land Surface Processes (Soil moisture, Snow cover, ) Atmospheric Noise - unpredictable climate signals produced by chance through cumulative effects of weather. This is large in middle latitudes, small in the Tropics. Major cause of uncertainty in forecasts, and especially true during ENSO-neutral conditions and Northern Hemisphere summer (convection, tropical systems).
Recent Conditions (3-Month running ONI) - 0.7 Winter & early spring months: Blue = La Nina Red = El Nino Black = ENSO Neutral 10
CPC/IRI Probabilistic ENSO Outlook (updated 9 Nov 2017) Official ENSO Forecast: La Nina conditions are predicted to continue (65-75% chance) at least through Northern Hemisphere Winter 2017-18, with a 51% chance of continuation through February-April 2018. Since we are at and expected to be at (weak) La Nina conditions for a while, then what are our outlooks based upon? Empirical (Statistical) and Dynamical models. 11
Start with Current Conditions (Drought Outlook only) 12
Current Forecasts (5-Day Total Precipitation) Moderate precipitation is expected along the Gulf and Atlantic Coast States, in the western Great Lakes region, and Tennessee Valley, with little or no precipitation expected elsewhere. 13
Current Forecasts (6-10 Day Outlooks) Odds are favorable for sub-median precipitation across most of the lower 48 States during December 10-14, with a tilt toward wet weather in the northern Plains, upper Midwest, northern New England, and Alaska. A pattern change should usher in sub-normal readings to the eastern half of the Nation while above normal temperatures envelop the West and Alaska. 14
Current Forecasts (8-14 Day Outlooks) Chances are favorable for sub-median precipitation throughout much of the contiguous U.S. with above-median precipitation limited to the northern Plains and upper Midwest during December 12-18. Below-normal temperatures should persist in the eastern half of the U.S. while the Far West & Alaska remains mild. 15
Current Forecasts; Week 3-4 Temperature & Precipitation Outlooks During the second half of December, odds favor a continuation of below-normal temperatures in the Northeast and above-normal readings in the West. Submedian precipitation is still probable throughout much of the Nation, with abovemedian precipitation limited to the northern Rockies and southern Alaska during December 16-29. Experimental 16
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Current Forecasts (1-Month [Dec17] Temperature Outlook) 20
Current Forecasts (1-Month [Dec17] Precipitation Outlook) 22
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Current Forecasts (3-Month [D17JF18] Temperature Outlook) 24
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Current Forecasts (3-Month [D17JF18] Precipitation Outlook) 26
Drought Forecasting: Many Different Contributions (Tools) Start with latest U.S. Drought Monitor D1 areas Short-Term Forecasts: (less than 1-Month) Climatologies And Analogs Long-Range Forecasts: (1- to 3-Months) (Note ENSO Status & Other Atmospheric/Oceanic Indicators)
Start with 11/14/17 US Drought Monitor Initial D17JF18 Seasonal Drought Outlook (released Nov. 16) Use the latest U.S. Drought Monitor D0 & D1 shape file areas From Tools - Determine if D1-D4 areas will: Persist, Improve, or be Removed; and if D0 & normal areas will Nov. 16, 2017 SDO 28
Primary Drought Outlook Inputs Short Term 6-10 Day Temp Probabilities HPC 5-Day Prec Totals 8-14 Day Prec Probabilities MRF 384-Hour Total Prec 29
Primary Drought Outlook Inputs Climos & Analogs Consecutive La Ninas Precip DJF La Nina1 La Nina2 30
Winter DJF Summer JJA Spring MAM Fall SON 31
Primary Drought Outlook Inputs Long Term NMME for OND12 PCP SPI Forecast based on CFSv2 1-Month Temp Probabilities 3-Month Prec Probabilities CFS Seasonal Precipitation 32
D17JF18 33
Dec17 34
Drought Outlook Narratives Summary & Discussion Summary - Short overall narrative. (Both MDO & SDO have Summary & Discussion) Discussion Long, detailed narrative by region that includes reasoning & confidence rating. 35
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N A T I O N A L O C E A N I C A N D A T M O S P H E R I C A D M I N I S T R A T I O N CPC Comprehensive Skill Metric (CSM) Comprehensive skill metric (CSM) based on all CPC extended range and long range outlooks. CSM includes over 1000 product issuances per year. Judged successful if its Heidke Skill Score exceeds a particular threshold. CSM shows continuous, improvement of CPC products. Improvement due to calibration enabled by GEFS reforecasts??
4-KM GRID Good Forecasts during developing La Nina & El Nino 38 Not so good Forecasts during Summer & ENSO Neutral
85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 Seasonal D.O. Verification Scores (% of Pixels Hit) RAW FCST SCORE SCORE FOR AN ALL PERSISTENCE FCST RAW FCST SCORE linear trend
65 55 45 35 25 15 5-5 -15-25 -35-45 -55-65 Seasonal D. O. Skill (Forecast Score minus Persistence Score)
100% Seasonal D. O. Verification (% of Pixels Hit) - Existing & Developing Drought 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Series1 Series2
80 Seasonal Drought Outlook: Median Percent of Area Successfully Forecast -- DJF 2009/10 - ASO 2017 Median 70 60 75.1 69.8 68.9 50 40 30 48.3 39.2 20 10 0 OFFICIAL DROUGHT OUTLOOK Persistence Forecast for ALL Existing Drought Areas D.O. Forecast of Improvement or Removal D.O. Forecast of Persistence D.O. Forecasts for ALL Existing Drought Areas 7.0 D.O. Forecast of Development OR Development in Areas Not Forecast
Monthly Drought Outlook Verification Statistics -- (Score, Baseline [or persistence], and skill) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% -10% -20% -30% -40% Score Baseline Skill Skill Linear Trend
Challenges 45
Next Steps in Drought Forecasting Short-Term: X X Modify 3-Month Outlook Categories (Some Improvement Removal, Improvement, or Persistence; Produce a 1-Month Outlook (ag-related) that replaces Updated 3-Month USDO; Additional GIS procedures to better automate & objectify USDO (like USDM); X Real-Time USDO Verification: Make more objective & automated; Create and post Public Documentation (Internet) for the USDO; Long-Term: Develop a R2O plan for long-term improvement of USDO: Improvement of Precipitation forecasts in the models is highest priority; Integration of Temperatures, Precipitation, and Soil Moisture Forecasts ; Engage the drought community for ideas on improving the USDO: Comparison of the (subjective) USDO with objective ones, such as objective SPI or one based upon the PDI; Continuation of the current manual forecast, with the objective forecasts used as input and run in parallel; Customer preferences between objective versus subjective USDOs; Develop a probabilistic, objective USDO; Develop a 2-month & 6-month DOs;
THANK YOU! Any Questions, contact: David.Miskus@noaa.gov (301) 683-3453 Climate Prediction Center: http://www.cpc.ncep.noaa.gov/ 47
Extended Range Forecasts