# Presentation: 781527

## DOWNSCALING:  High Resolution MOS Guidance

**J. Paul Dallavalle/MDL**
**2****nd**** North American Ensemble Forecast System Workshop**
**November 16-18, 2004**

**Notes:**
The amount of observational and forecast data produced by the National Weather Service has increased dramatically via the implementation of new technology and the infusion of science.  We now have much more information than we can effectively communicate, and the volume of this data will continue to increase.

The need for high-quality weather, water, and climate data and predictions is escalating at a dramatic rate.  We face a challenge managing and sharing information with our partners and customers.

The NWS is implementing an advanced forecasting process which will dramatically change our internal forecast process and the kinds of products and level of service we provide our customers and partners.

## What is Downscaling?

**Producing ****site-specific forecasts**** or forecasts with higher spatial and/or temporal resolution than the output from the numerical weather prediction model on which the forecasts are based.**

## What is MOS?

**Relates observations of the weather element to be predicted (predictand) to appropriate variables (predictors) via a statistical method**
**Predictors can include:**
**	****NWP model output interpolated to observing site**
**	****Prior observations**
**	****Geoclimatic data – terrain, normals, etc.**
**Current statistical method:  multiple linear regression (forward selection)**

## MOS Characteristics

** ****Yields site-specific guidance **
** ****Two developmental approaches:**
**Single-station regression equations **
**Regionalized operator regression equations (geoclimatic predictors provide site-specific information)**
** ****Combine effects of synoptic-scale forcing and  local site response**
** ****Not**** a mesoscale forecast system**

## Current MOS Direction

**Implement high resolution gridded MOS for elements available in the National Digital Forecast Database (NDFD) **
**  ****See:  http://www.nws.noaa.gov/ndfd/**
**Support the National Digital Guidance Database (NDGD) and efforts to quantify the uncertainty of the guidance**

## NDFD Max Temperature Forecast

## Objectives of Gridded MOS

** ****Produce MOS guidance on a high-resolution grid (2.5 to 5 km spacing)**
** ****Generate guidance with detail sufficient for forecast initialization at local NWS Forecast Offices**
** ****Generate guidance with a level of accuracy comparable to that of the station-oriented guidance**

## Approach to Gridded MOS

** ****Use h****igh-resolution geoclimatic variables such as terrain, slope, aspect, land use, normals, etc. **
** ****Use observations from remote-sensing networks such as lightning, precipitation amounts, satellite clouds**
** ****Use mesonet surface observations **
** ****Develop single-station and regionalized MOS equations as appropriate**
** ****Apply regionalized equations to high-resolution grid**
** ****Blend single-station and regional guidance**

## Prototype Gridded MOS 

-  **GFS-based; 0000/1200 UTC cycles only**
** ****Selected Elements**
***Max/Min temperature, 2-m temperature & dewpoint***
***Probability of precipitation***
***Wind direction and speed***
***Probability of thunderstorms***
***Categorical 24-h snowfall amount***
** ****Restricted area for initial implementation**
** ****Scheduled initially for fall 2004**

## Gridded MOS - CONUS

**Notes:**
Western tile (in red) over the CONUS grid – 5km resolution output grid

## High Resolution MOS

## Western Gridded MOS Tile

## San Francisco Bay Area

## Salt Lake City Area

## Creating gridded observationsStrikes are summed over the appropriate time period and assigned to the center of the grid boxes

| ××××  |  |  |  |  |
| --- | --- | --- | --- | --- |
|  |  |  × |   × | ××× |
| × |  |  |  | ×× |
|  |  | ×× | ×
 |  |

|    |  |  |  |  |
| --- | --- | --- | --- | --- |
|  |  |   |   |   |
|   |  |  |  |   |
|  |  |   |   |  |

- = thunderstorm

- = no thunderstorm

## 20-km MOS Thunderstorm Grid  

**Notes:**
Red is 40  Some boxes, even at 40-km resolution do not have a ‘traditional observation (i.e. METAR)
Green is 20
Blue is 10
Black is 5  note that when the resolution is doubled, we have essentially increase the number of grid points by a factor of 4.  In our MOS system, we have gone from processing 10000 ‘stations’ to almost a million. 

## Gridded MOS Max Temp

** ****First Guess**
** ****Day 1 Max, valid 10/20/04**
** ****Regionalized operator equation**

## Gridded MOS Max Temp Analysis

**Analysis**
** ****Day 1 Max, valid 10/20/04**
** ****Guidance at METAR sites only**

## Gridded MOS Max Temp Analysis

**Analysis**
** ****Day 1 Max, valid 10/20/04**
** ****Guidance at all available sites**
** ****Blending not tuned yet**

## Gridded MOS Max Temp Analysis

**Analysis**
** ****Day 1 Max, valid 10/20/04**
** ****Guidance at all available sites only**
** ****Some tuning of analysis**

## Gridded MOS Min Temp

** ****First Guess**
** ****Day 2 Min, valid 10/21/04**
** ****Regionalized operator equation**

## Gridded MOS Min Temp Analysis

**Analysis**
** ****Day 2 Min, valid 10/21/04**
** ****Guidance at METAR sites only**

## Gridded MOS Min Temp Analysis

**Analysis**
** ****Day 2 Min, valid 10/20/04**
** ****Guidance at all available sites**
** ****Blending not tuned yet**

## Gridded MOS Day 1 Max, valid 8/17/04

## Conclusions

** ****Need geoclimatic data**
** ****Need to be wary of mesonet observations**
** ****Need to solve computational time issues**
** ****Need to answer more questions**
**Is 1****st**** guess adequate?**
**Will our probabilities satisfy what we want?**
**Will forecasters forego the single station guidance?**

## Accuracy of Regional Temperature Equations

## Accuracy of Regional Wind Speed Equations

## Conclusions

** ****Need geoclimatic data**
** ****Need to be wary of mesonet observations**
** ****Need to solve computational time issues**
** ****Need to answer more questions**
**Is 1****st**** guess adequate?**
**Will our probabilities satisfy what we want?**
**Will forecasters forego the single station guidance?**

## 3H Eta MOS probability forecasts ending  at 0000 UTC on August 27, 2002

**40-km 21-24h period**
**10% contour interval**

**20-km 21-24h period**
**10% contour interval**

## Conclusions

** ****Need geoclimatic data**
** ****Need to be wary of mesonet observations**
** ****Need to solve computational time issues**
** ****Need to answer more questions**
**Is 1****st**** guess adequate?**
**Will our probabilities satisfy what we want?**
**Will forecasters forego the single station guidance?**

## Guidance for Co-op Sites

*** ***
**GFSX-BASED MOS COOP MAX/MIN GUIDANCE 11/13/04  0000 UTC                        **
**          ****SAT 13| SUN 14| MON 15| TUE 16| WED 17| THU 18| FRI 19| SAT 20|       **
** ****ABNA1        64| 44  61| 38  61| 38  67| 44  69| 44  70| 46  67| 46  65| **
** ****...**
** ****ANNM2        54| 31  53| 34  59| 38  62| 36  55| 38  61| 41  61| 36  57|       **
** ****BERM2        54| 35  54| 40  59| 43  58| 44  57| 44  60| 46  60| 44  57|       **
** ****BTVM2        47| 30  49| 32  58| 35  58| 35  55| 37  58| 39  59| 37  55|       **
** ****CBLM2        48| 26  52| 31  57| 30  60| 34  57| 36  57| 33  58| 32  54|       **
** ****CHEM2        45| 28  50| 33  59| 33  58| 33  54| 35  58| 36  57| 34  55|       **
** ****CNWM2        51| 30  53| 32  58| 37  60| 35  55| 37  60| 39  59| 35  58|       **
** ****DMAM2        44| 25  45| 32  52| 34  56| 36  52| 35  54| 37  55| 36  51|       **
** ****ELCM2        47| 23  49| 27  56| 30  59| 31  55| 32  57| 33  59| 32  55|       **
** ****EMMM2        46| 26  50| 30  57| 33  60| 34  52| 36  58| 37  58| 33  57|       **
** ****FREM2        46| 32  52| 34  57| 37  62| 36  54| 39  59| 39  60| 38  55|       **
** ****FRSM2        38| 21  42| 28  50| 32  53| 34  47| 33  50| 35  49| 34  45|       **
** ****GLDM2        44| 27  48| 29  58| 33  61| 32  54| 35  57| 36  58| 32  53|       **
** ****HAGM2        47| 28  50| 31  58| 34  59| 34  57| 37  59| 38  59| 35  58|       **
** ****KAPG         47| 31  50| 36  57| 39  58| 36  53| 39  57| 40  59| 36  55|       **
** ****LRLM2        48| 31  50| 36  58| 39  60| 38  54| 39  58| 42  61| 40  54|       **
** ****MECM2        48| 28  45| 32  56| 37  57| 35  54| 38  59| 39  58| 36  55|       **
** ****MLLM2        46| 29  48| 33  55| 34  58| 35  52| 36  55| 38  55| 36  52|       **
** ****NARD2        48| 31  52| 33  59| 34  60| 37  58| 37  61| 38  62| 36  56|       **
** ****OLDM2        47| 21  49| 24  52| 29  57| 29  54| 32  55| 32  55| 29  49|       **
***  ***
** **