# Presentation: 018046

## Model Output Statistics (MOS) - Objective Interpretation of NWPModel Output

**Millersville U. @ NCEP - December 9, 2005**

**Mark S. Antolik**
**Meteorological Development Laboratory**
**Statistical Modeling Branch**
**NOAA/National Weather Service**
**Silver Spring, MD**

- (301) 713-0023  ext. 110
- email: mark.antolik@noaa.gov

## OUTLINE

**1.  Why objective statistical guidance?**
**2.  What is MOS?**
**       ****Definition and characteristics**
**       ****The “traditional” MOS product suite**
**            ****(NGM, eta, GFS) **
**       ****Recent additions to the lineup**
**3.  Simple regression examples / Probability**
**4.  Development strategy -    **
**             ****MOS in the “real world”**
**5.  Verification **
**6.  Where we’re going - The future of MOS**

## WHY STATISTICAL GUIDANCE?

**Add value to direct NWP model output**
** ****Objectively interpret model **
**    ****-  remove systematic biases **
**    ****-  quantify uncertainty**
** ****Predict what the model does not**
** ****Produce site-specific forecasts**
**       ****(i.e. a “downscaling” technique)**
**Assist forecasters**
** “****First Guess” for expected local conditions**
** “****Built-in” model/climo memory for new staff**

## MOS Max Temp  vs.  Direct Model Output

## A SIMPLE STATISTICAL MODEL

- Relative Frequency of Precipitation as a Function of12-24 Hour NGM Model-Forecast Mean RH

**NGM MEAN RELATIVE HUMIDITY (%)**

**OBSERVED REL. FREQUENCY**

**0**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**0.0**

**0.1**

**0.2**

**0.3**

**0.4**

**0.5**

**0.6**

**0.7**

**0.8**

**0.9**

**1.0**

**3-YR SAMPLE;  200 STATIONS**

**1987-1990 COOL SEASON**

**47%**

##  What is MOS?

## MODEL OUTPUT STATISTICS (MOS)

** ****Numerical Weather Prediction (NWP) Model**
**       ****Forecasts               **
**2.  Prior Surface Weather Observations**
**3.  Geoclimatic Information**
**Current Statistical Method: **
**              ****MULTIPLE LINEAR REGRESSION**
**              ****(Forward Selection)**

**Relates observed weather elements ****(PREDICTANDS)**** to appropriate variables ****(PREDICTORS)**** via a**
**statistical approach.**
**Predictors are obtained from:**

## MODEL OUTPUT STATISTICS (MOS)

**Properties**

**Mathematically simple, yet powerful**
**Need historical record of observations**
**   ****at forecast points  **
**   ****(Hopefully a long, stable one!)**
**Equations are applied to future run of **
**   ****similar forecast model**
**      **

## MODEL OUTPUT STATISTICS (MOS)

**Properties (cont.)**

**Non-linearity can be modeled by using**
**   ****NWP variables and transformations**
**Probability forecasts possible from a**
**   ****single run of NWP model**
**Other statistical methods can be used**
**   ****e.g. Polynomial or logistic regression;**
**          ****Neural networks**

## MODEL OUTPUT STATISTICS (MOS)

**ADVANTAGES**
** ****Recognition of model predictability**
** ****Removal of some systematic model bias**
** ****Optimal predictor selection**
** ****Reliable probabilities**
** ****Specific element and site forecasts**
**DISADVANTAGES**
** ****Short samples**
** ****Changing NWP models**
** ****Availability & quality of obs **

## “Traditional” MOStext products

## GFS MOS GUIDANCE MESSAGEFOUS21-26   (MAV)

**KLNS   GFS MOS GUIDANCE   11/29/2004  1200 UTC                      **
**DT /NOV  29/NOV  30                /DEC   1                /DEC   2 **
**HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 **
**N/X                    28          48          35          49    33 **
**TMP  43 44 39 36 33 32 31 39 46 45 41 38 37 39 41 44 45 44 40 40 35 **
**DPT  27 27 28 29 29 29 29 33 35 35 36 35 36 39 41 42 37 34 30 30 28 **
**CLD  CL BK BK BK OV OV OV OV OV OV OV OV OV OV OV OV OV BK CL CL CL **
**WDR  34 36 00 00 00 00 00 00 00 14 12 12 10 11 12 19 28 29 29 29 28 **
**WSP  06 02 00 00 00 00 00 00 00 01 02 04 04 06 07 08 15 17 18 09 05 **
**P06         0     0     4     3    11    65    94    96     7  0  0 **
**P12                     6          19          94          96     0 **
**Q06         0     0     0     0     0     3     4     4     0  0  0 **
**Q12                     0           0           4           2     0 **
**T06      0/ 0  0/18  0/ 3  0/ 0  0/ 0  0/18  2/ 1 10/ 4  0/ 3  1/ 0 **
**T12            0/26        0/17        0/27       10/25     1/38    **
**POZ   2  0  0  1  2  4  4  0  1  1  2  3  3  1  1  0  2  1  2  3  1 **
**POS  13  2  1  2  1  0  0  0  0  0  0  0  0  2  0  0  0  3  0  9 28 **
**TYP   R  R  R  R  R  R  R  R  R  R  R  R  R  R  R  R  R  R  R  R  R **
**SNW                     0                       0                 0 **
**CIG   8  8  8  8  7  7  7  8  8  7  7  7  4  2  3  3  6  7  8  8  8 **
**VIS   7  7  7  7  7  7  7  7  7  7  7  7  5  5  4  2  6  7  7  7  7 **
**OBV   N  N  N  N  N  N  N  N  N  N  N  N BR BR BR BR  N  N  N  N  N**

## Eta MOS GUIDANCE MESSAGEFOUS44-49   (MET)

** ****KTHV   ETA MOS GUIDANCE   11/28/2005  1200 UTC                      **
** ****DT /NOV  28/NOV  29                /NOV  30                /DEC   1 **
** ****HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 **
** ****N/X                    60          65          52          54    28 **
** ****TMP  58 60 58 61 65 66 66 60 62 61 62 61 59 57 54 52 53 50 41 35 32 **
** ****DPT  50 52 52 54 57 58 58 55 58 59 57 56 54 52 49 43 39 36 34 29 27 **
** ****CLD  OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV SC CL SC BK **
** ****WDR  15 13 12 14 16 15 13 17 16 15 15 16 18 24 29 29 31 32 30 27 32 **
** ****WSP  05 07 07 10 12 12 10 10 10 09 08 08 07 07 05 10 09 06 03 01 03 **
** ****P06        14    62    87    94    91    90    71    21     6  6  0 **
** ****P12                    88         100          93          28     7 **
** ****Q06         0     1     2     3     4     4     2     0     0  0  0 **
** ****Q12                     1           4           4           0     0 **
** ****T06      2/ 0  7/ 0  8/ 4 13/ 2 25/ 3 28/ 2 21/ 2  9/ 1  3/ 3999/99 **
** ****T12            7/ 0       22/ 4       41/ 4       24/ 3   999/99    **
** ****SNW                     0                       0                 0 **
** ****CIG   3  5  3  3  2  2  2  3  5  4  3  3  3  4  5  6  6  8  8  8  8 **
** ****VIS   5  6  6  5  5  3  3  3  5  5  4  2  3  3  7  7  7  7  7  7  7 **
** ****OBV  BR  N BR BR BR BR BR BR HZ BR BR BR BR BR  N  N  N  N  N  N  N**** **

## GFS / Eta MOS  vs.  NGM MOS

**MORE STATIONS:**
**   ****Now at approx. 1650 Forecast Sites **
**   ****(CONUS, HI, PR)**
**MORE FORECASTS:**
**   ****Available at projections of 12- 84 hours**
**   ****GFS available for 0600 and 1800 UTC cycles**
**BETTER RESOLUTION:**
**   ****GFS predictors on 95.25 km grid;  Eta on 32 km**
**   ****Predictor fields available at 3-h timesteps**
**   ****Predictors available beyond 48-h projection **
** ***** No extrapolative forecasts**** **
**DEPENDENT SAMPLE NOT “IDEAL”:**
**   ****Fewer Seasons**
**   ****Non-static underlying NWP model**

## Slide 15

## Slide 16

## GFS / Eta MOS  vs.  NGM MOS

**MORE STATIONS:**
**   ****Now at approx. 1650 Forecast Sites **
**   ****(CONUS, AK, HI, PR)**
**MORE FORECASTS:**
**   ****Available at projections of 12- 84 hours**
**   ****GFS available for 0600 and 1800 UTC cycles**
**BETTER RESOLUTION:**
**   ****GFS predictors on 95.25 km grid;  Eta on 32 km**
**   ****Predictor fields available at 3-h timesteps**
**   ****Predictors available beyond 48-h projection **
** ***** No extrapolative forecasts**** **
**DEPENDENT SAMPLE NOT “IDEAL”:**
**   ****Fewer Seasons**
**   ****Non-static underlying NWP model**

## GFSX MOS GUIDANCE MESSAGEFEUS21-26   (MEX)

** ****KCXY   GFSX MOS GUIDANCE  11/26/2004  0000 UTC                       **
** ****FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      **
** ****FRI  26| SAT 27| SUN 28| MON 29| TUE 30| WED 01| THU 02| FRI 03 CLIMO**
** ****X/N  43| 29  47| 40  55| 35  51| 29  45| 32  40| 36  42| 30  45 31 46**
** ****TMP  37| 32  43| 43  46| 37  41| 32  39| 35  36| 38  37| 33  37      **
** ****DPT  24| 27  37| 40  32| 28  28| 26  31| 32  30| 32  27| 24  25      **
** ****CLD  PC| OV  OV| OV  PC| CL  PC| PC  OV| OV  OV| PC  CL| CL  CL      **
** ****WND  10|  5  11| 11  16| 10  10|  5   9|  6  10| 12  14| 12  12      **
** ****P12   0|  5  13| 91  13|  3   9| 14  24| 52  54| 48  21| 12  25 20 18**
** ****P24    |     16|    100|      9|     26|     62|     72|     25    29**
** ****Q12   0|  0   0|  3   0|  0   0|  0   0|  2   2|  2    |             **
** ****Q24    |      0|      3|      0|      0|      4|       |             **
** ****T12   0|  0   0|  3   0|  0   0|  0   4|  6   4|  3   1|  1   1      **
** ****T24    |  0    |  3    |  0    |  0    |  6    |  4    |  1          **
** ****PZP  12|  9  12|  4   3|  5   6| 10   8|  8   3| 16  10| 12   8      **
** ****PSN  62| 15   3|  0   0| 10   9| 15  24|  1   0|  9  32| 27  18      **
** ****PRS  26| 24   7|  0  17| 18  20| 13  15|  1   2| 18   9| 11  11      **
** ****TYP   S| RS   R|  R   R|  R   R|  R  RS|  R   R|  R  RS| RS   R      **
** ****SNW    |      0|      0|      0|      0|       |       |**

## Recent additions to the MOS product lineup

##  44004  GFS MOS GUIDANCE   11/22/2005  1200 UTC 
 DT  /NOV 22/NOV 23                 /NOV 24                 /NOV 25 
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 
 TMP  58 53 49 49 50 48 46 44 44 45 47 48 51 54 56 60 62 61 59 51 47 
 WD   23 25 27 28 28 29 29 28 28 27 27 25 22 22 22 23 23 23 24 27 28 
 WS   33 31 29 25 23 22 24 25 23 18 14 12 14 19 26 29 30 29 29 28 24 
 WS10 36 34 31 26 25 24 26 27 25 19 15 13 15 21 28 31 32 31 31 30 26 

 DT  /NOV 25         / 
 HR   09 12 15 18 21 00 
 TMP  45 45 45 47 47 47 
 WD   29 29 28 30 29 34 
 WS   18 15 10 10 13 12 
 WS10 20 16 11 11 14 13 

** ****DT  /NOV 22/NOV 23                 /NOV 24                 /NOV 25 **
** ****HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 **
** ****TMP  58 53 49 49 50 48 46 44 44 45 47 48 51 54 56 60 62 61 59 51 47 **
** ****WD   23 25 27 28 28 29 29 28 28 27 27 25 22 22 22 23 23 23 24 27 28 **
** ****WS   33 31 29 25 23 22 24 25 23 18 14 12 14 19 26 29 30 29 29 28 24 **
** ****WS10 36 34 31 26 25 24 26 27 25 19 15 13 15 21 28 31 32 31 31 30 26 **
** ****DT  /NOV 25         / **
** ****HR   09 12 15 18 21 00 **
** ****TMP  45 45 45 47 47 47 **
** ****WD   29 29 28 30 29 34 **
** ****WS   18 15 10 10 13 12 **
** ****WS10 20 16 11 11 14 13**

**Marine MOS**

**Marine MOS sites**

**Standard MOS sites**

## MOS Snowfall Guidance

- 36-hr forecast
- 12Z 12/05/03 – 12Z 12/06/03

- 6 - <8

- 4 - < 6

- 2 - < 4

- >Trace - 2

- Verification

**Uses Observations from Cooperative Observer Network**

## Max/Min Guidance for Co-op Sites

**         ****THU 02| FRI 03| SAT 04**
**GYLP1    30  41| 29  41| 28  46**
**HAWP1    28  42| 24  39| 20  38**
**HBGP1    34  47| 28  45| 27  43**
**HRBP1    35  45| 29  44| 29  43**
**INDP1    28  44| 27  44| 28  46**
**JMSP1    26  39| 24  40| 28  42**
**KANP1    24  34| 22  33| 22  36**
**LAPP1    27  37| 25  35| 22  36**
**LBGP1    33  45| 28  42| 25  42**
**LCRP1    33  46| 27  46| 27  46**
**LDVP1    29  49| 25  45| 23  42**
**LEBP1    30  46| 26  43| 24  45                                                **
**LHGP1    30  45| 24  44| 25  41                                                **
**LMPP1    26  36| 25  37| 26  41                                                **
**LNVP1    28  38| 27  38| 27  41                                                **
**LOKP1    32  43| 27  43| 27  41**
**LRLP1    29  47| 24  43| 23  40                                                **
**LSTP1    34  46| 29  45| 29  42                                                **
**MATP1    29  45| 24  42| 22  38                                                **
**MCKP1    27  40| 27  41| 26  45                                                **
**MERP1    22  40| 22  41| 24  43 **

**Max/Min Guidance for Co-op Sites**

**Landisville, PA**

**Lancaster 2 NE**

## Western Pacific MOS Guidance

**NSTU   GFS MOS GUIDANCE   12/05/2005  1200 UTC**
**DT /DEC   5/DEC   6                /DEC   7                /DEC   8**
**HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12**
**WDR  12 11 11 11 09 09 10 11 09 09 08 11 09 04 32 00 00 05 06 03 30**
**WSP  07 08 09 10 09 06 04 03 04 07 08 05 05 02 01 00 00 05 06 03 01**

**Wake, US**

**Midway, US**

**Saipan, ROM**

## Very recent additions

**GFSX MOS:**
**  ****New 1200 UTC package (no clds, wind, ptype)**** **
**Eta MOS:**
**  ****Visibility and obstruction to vision forecasts                         **
**Marine MOS:**
**  ****Temperature forecasts**
**Western Pacific MOS wind guidance**

**New within the past year...**

## Application of Linear Regressionto MOS Development

## MOS LINEAR REGRESSION

- JANUARY 1 - JANUARY 30,  1994   0000 UTC**KCMH**

**18-H NGM 850-1000 MB THICKNESS (M)**

**TODAY'S MAX (°F)**

**1150**

**1200**

**1250**

**1300**

**1350**

**10**

**20**

**30**

**40**

**50**

**60**

**0**

**-10**

## MOS LINEAR REGRESSION

- JANUARY 1 - JANUARY 30,  1994   0000 UTC**KCMH**

**18-H NGM 850-1000 MB THICKNESS (M)**

**TODAY'S MAX (°F)**

**1150**

**1200**

**1250**

**1300**

**1350**

**10**

**20**

**30**

**40**

**50**

**60**

**0**

**-10**

**RV=93.1%**

**MAX T = -352 + (0.3 x 850-1000 mb THK)**

## REDUCTION OF VARIANCE

- A measure of the “goodness” of fit andPredictor / Predictand correlation

**PREDICTOR**

**PREDICTAND**

**MEAN**

**RV**

**RV**

**Variance  -  Standard Error**

**=**

**Variance**

- {

- }

**UNEXPLAINED VARIANCE**

*****

## MOS LINEAR REGRESSION

- JANUARY 1 - JANUARY 30,  1994   0000 UTC**KUIL**

**18-H NGM 850-1000 MB THICKNESS (M)**

**TODAY'S MAX (°F)**

**1250**

**1300**

**1350**

**1400**

**30**

**40**

**50**

**60**

**RV=26.8%**

## MOS LINEAR REGRESSION

- DECEMBER 1 1993 - MARCH 5 1994   0000 UTC**KCMH**

**AVG. 12-24 H NGM ~1000 - 500 MB RH**

**12-24 H PRECIPITATION ≥ .01"**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**0**

**1**

## MOS LINEAR REGRESSION

- DECEMBER 1 1993 - MARCH 5 1994   0000 UTC**KCMH**

**AVG. 12-24 H NGM ~1000 - 500 MB RH**

**12-24 H PRECIPITATION ≥ .01"**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**0**

**1**

- RV=36.5%

## MOS LINEAR REGRESSION

- DECEMBER 1 1993 - MARCH 5 1994   0000 UTC**KCMH**

**AVG. 12-24 H NGM ~1000 - 500 MB RH**

**12-24 H PRECIPITATION ≥ .01"**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**0**

**1**

- RV=36.5%

- RV=42.4%

## MOS LINEAR REGRESSION

- DECEMBER 1 1993 - MARCH 5 1994   0000 UTC**KCMH**

**AVG. 12-24 H NGM ~1000 - 500 MB RH**

**12-24 H PRECIPITATION ≥ .01"**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**0**

**1**

- RV=36.5%

- RV=42.4%

**RV=44.9%**

**POP = -0.234 + (0.007 X MRH) +**

-       **(0.478 X BINARY MRH (70%))**

## EXAMPLE REGRESSION EQUATIONS

**Y = a + bX**

- _CMH MAX TEMPERATURE EQUATION_

- _CMH PROBABILITY OF PRECIPITATION EQUATION_

- MAX T  =  -352  +  (0.3 x 850 -1000 mb THICKNESS)

- POP =   -0.234  +  (0.007 x MEAN RH)

-                    + (0.478 x BINARY MEAN RH CUTOFF AT 70%)*

- *(IF MRH ≥ 70% BINARY MRH = 1; else BINARY MRH = 0)

## If the predictand is BINARY, MOS regression equations produceestimates of event PROBABILITIES...

**KCMH**

**AVG. 12-24 H NGM ~1000 - 500 MB RH**

**12-24 H PRECIPITATION ≥ .01"**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**0**

**1**

- 3 Events

- 7 Events

**RF= 30%**

**P = 30%**

## Making a PROBABILISTIC statement...

**Quantifies the uncertainty !**

## DEFINITION of PROBABILITY

- (Wilks, 1994)

-    LONG TERM RELATIVE FREQUENCY OF AN EVENT
-    DEGREE OF BELIEF OR QUANTIFIED JUDGMENT
-      ABOUT THE OCCURRENCE OF AN UNCERTAIN EVENT

-   POINT PROBABILITY
-   AREAL PROBABILITY
-   CONDITIONAL PROBABILITY

- Assessment of probability is ***EXTREMELY**** *dependent upon how predictand “event” is defined:

**KEEP IN MIND:**

- - Time period of consideration
- - Area of occurrence
- - Dependent upon another event?

## 3H Eta MOS thunderstorm probability forecasts   valid 0000 UTC  8/27/2002  (21-24h proj)

**AREAL ****PROBABILITIES**

**What if these were 6-h forecasts?**

## Designing an Operational MOS System: Putting theory into practice...

## DEVELOPMENTAL CONSIDERATIONS

**Selection (and QC!) of Suitable **
**  ****Observational Datasets**
**  ****ASOS?   Remote sensor?   Which mesonet?**

**MOS in the real world**

## Suitable observations?

**Appropriate Sensor?**

**Good siting?**

**Real or Memorex?**

**Photo Courtesy W. Shaffer**

## DEVELOPMENTAL CONSIDERATIONS

**Selection (and QC!) of Suitable **
**  ****Observational Datasets**
**  ****ASOS?   Remote sensor?   Which mesonet?**
**Predictand Definition**
**   ****Must be precise !!**

**MOS in the real world**

## PREDICTAND  DEFINITION

**Daytime Maximum Temperature**
**   “****Daytime” is 0700 AM - 0700 PM LST**
**Nighttime Minimum Temperature**
**   “****Nighttime” is 0700 PM - 0800 AM LST**
**Probability of Precipitation**
**     ****Precipitation occurrence is accumulation **
**     ****of ≥ 0.01 inches of liquid-equivalent at a**
**     ****gauge location within a specified period**

**Max/Min and PoP**

## DEVELOPMENTAL CONSIDERATIONS

**Selection (and QC!) of Suitable **
**  ****Observational Datasets**
**  ****ASOS?   Remote sensor?   Which mesonet?**
**Predictand Definition**
**   ****Must be precise !!**
**Choice of Predictors**
**  “****Appropriate” formulation**
**   ****Binary or other transform?**

**MOS in the real world**

## “APPROPRIATE” PREDICTORS

-  DESCRIBE PHYSICAL PROCESSES ASSOCIATED
-     WITH  OCCURRENCE OF PREDICTAND
-    “MIMIC” FORECASTER THOUGHT PROCESS

**(VERTICAL VELOCITY)  X  (MEAN RH)**

**i.e. for POP:**

## DEVELOPMENTAL CONSIDERATIONS

**Terms in Equations; Selection Criteria**

**(cont.)**

## “REAL” REGRESSION EQUATIONS

- MULTIVARIATE

- , of form:

**Y =  a  + a  X  + a  X  + ... + a  X**

-  large:

**FORWARD SELECTION**

-  procedure determines the

**2**

**N**

**N**

**1**

**0**

**1**

**2**

-     MOS regression equations are

-     Where,

-               the "a's" represent  COEFFICIENTS

-               the "X's" represent  PREDICTOR variables

-     The maximum number of terms, N, can be

-                For NGM QPF,  N = 15      For NGM VIS,  N = 20

-     The

-     predictors and the order in which they appear.

***QUITE***

## DEVELOPMENTAL CONSIDERATIONS

**Terms in Equations; Selection Criteria**
**Dependent Data**
**  ****Sample Size, Stability, Representativeness**
**       ****AVOID OVERFIT !!**
**  ****Stratification - Seasons**
**  ****Pooling – Regions**

**(cont.)**

## MOS LINEAR REGRESSION

- OCTOBER 1 1993 - MARCH 31 1994   0000 UTC**KUIL**

**12-24 H NGM PRECIPITATION AMOUNT (IN.)**

**12-24 H PRECIPITATION ≥ 1.0"**

- 0.00

- 0.25

- 0.50

- 0.75

- 1.00

- 0

- 1

- 0

**RV=14.2%**

## AVN/GFS  Cool Season PoP/QPF Regions

**With AVN MOS forecast sites (1406)**

## DEVELOPMENTAL CONSIDERATIONS

**Terms in Equations; Selection Criteria**
**Dependent Data**
**  ****Sample Size, Stability, Representativeness**
**       ****AVOID OVERFIT !!**
**  ****Stratification - Seasons**
**  ****Pooling – Regions**
**Categorical Forecasts?**

**(cont.)**

## MOS BEST CATEGORY SELECTION

**MOS BEST CATEGORY SELECTION**

**           ****KDCA 12-Hour QPF Probabilities**                         48-Hour Projection valid 1200 UTC 10/31/93

- NO

**PROBABILITY (%)**

- NO

- NO

- NO

- 4

- 1

- 6

- 3

- 2

- 5

- 0

- YES

- YES

**THRESHOLD**

**EXCEEDED?**

**TO MOS GUIDANCE MESSAGES**

## How well do we do?MOS Verification

## Degrees (F)

**Degrees (F)**

## Temperature Verification - 0000 UTCCool Season 2002 -2003

## Temperature Verification - 0000 UTCCool Season 2002 -2003

- Temperature Verification - 0000 UTCCool Season 2002 -2003

## Max Temperature Verification

- LFM

- NGM

- EDAS

- AVN

- Day/Nite

**Max Temperature Verification**

- Cool Season; 1966 - 2003

- Perf. Pg. /
- PE MOS

**24-h**

**48-h**

## MOS:  Today and Beyond

## End of an era?

**WANTED!****   ****High-resolution, gridded guidance for NDFD**

## The Future of MOS

**GFSX MOS:**
** ****Changes to cloud and wind predictands                          **
** ****(Instantaneous values, post-process to avg.)**
**Eta MOS:**
** ****Eta/WRF re-evaluation, possible phaseout****   **
**Western Pacific MOS:**
** ****Add new elements (PoP, T, T****d****, Max/Min, Cld)**
**General:**
** ****Periodic addition of new CONUS sites**
** ****Gradual phaseout of station-oriented graphics**

**“****Traditional” Station-oriented Products**

##  GFSX MOS Day 7 Maximum Temperature 

**http://www.nws.noaa.gov/mdl/synop**

## The Future of MOS

**“****Enhanced-Resolution” MOS Systems**

**“****MOS at any point”**
**   ****Support new NWS digital forecast database**
**       ****2.5 km - 5 km**** ****resolution**
**   ****Emphasis on high-density surface networks**
**       ****Co-Op, buoy, mesonet**
**   ****Equations valid away from observing sites**
**   ****Use high-resolution geophysical data **

## Gridded MOS Domains

## Geophysical Datasets

**5-km Terrain**

**5-km Land Cover**

## Slide 65

## Slide 66

## Slide 67

## Gridded MOS – Central CA

## Gridded MOS Concept - Step 1

**Gridded MOS Concept - Step 1**

**“****Blending” first guess and high-density station forecasts**

**First guess field from**
** ****Generalized Operator Equation **
**or other source**

**First guess + guidance**
**at all available sites**

**Day 1 Max Temp 00 UTC  03/03/05**

**Day 1 Max Temp**
**00 UTC  03/03/05**

## Gridded MOS Concept - Step 2

**Gridded MOS Concept - Step 2**

**First guess + station forecasts +**
** ****terrain **

**First guess + guidance**
**at all available sites**

**Add further detail to analysis with high-resolution geophysical data and “smart” interpolation**

**Day 1 Max Temp**
**00 UTC  03/03/05**

**Day 1 Max Temp**
**00 UTC  03/03/05**

## The Future of MOS

**“****Enhanced-Resolution” MOS Systems**

**“****MOS at any point”**
**   ****Support new NWS digital forecast database**
**       ****2.5 km - 5 km**** ****resolution**
**   ****Emphasis on high-density surface networks**
**       ****Co-Op, buoy, mesonet**
**   ****Equations valid away from observing sites**
**   ****Use high-resolution geophysical data **
**“****True” gridded MOS **
**   ****Observations and forecasts valid on fine grid**
**   ****Use remotely-sensed predictand data**
**   ****e.g.  PoP/QPF “Demonstration” System**
**       ****    ****4-km HRAP grid; WSR-88D **

## Remotely-sensed precipitation data

**Remotely-sensed precipitation data**

**Satellite-based effective cloud amount**

## REFERENCES

**Wilks,D.:  Statistical Methods in the                       Atmospheric Sciences, Chap. 6, p. 159 - 210.**
**Draper, N.R., and H. Smith:  Applied                       Regression Analysis, Chap. 6, p. 307 - 308.**
**Glahn, H.R., and D. Lowry, 1972:  The use of         model output statistics in objective weather     forecasting, **_**JAM**_**, 11, 1203 - 1211.**
**Carter, G.M., et al., 1989:  Statistical forecasts      based on the NMC’s NWP System, **_**Wx. &**_**    **_**Forecasting**_**, p. 401 - 412.**