PERLFMNGMCONNWSFO
ME.15.15-.62-.22.49
MAE6.62 (57.72)3.35 (16.48)3.38 (17.28)3.04 (7.81)2.80
RMSE9.16 (58.48)4.48 (15.19)4.37 (13.01)4.04 (5.76)3.80


Table 1: Mean error (ME), mean absolute error (MAE), and root mean square error (RMSE) in šF for five different high temperature forecast systems valid during the 12-24 hour period for Oklahoma City. Forecast systems are persistence (PER), MOS guidance from the LFM (LFM), MOS guidance from the NGM (NGM), an average of the LFM and NGM MOS (CON), and the forecast from the NWS Forecast Office in Norman, Oklahoma (NWS). Numbers in parentheses indicate percentage improvement by NWS forecast over the forecast for the given measure.


RangePERLFMNGMCONNWSFO
­36-­4010000
­31-­3540000
­26-­3040000
­21-­25110000
­16-­20160100
­11-­15336220
­6-­105240533627
­1-­5114223276268198
03966575887
1­ 5173192153182230
6­ 108449373440
11­ 1542121087
16­ 20110121
21­ 2542000
26­ 3010000
31­ 3510000
36­ 4000000
Errors ¾ 5 šF326 (55.3)481 (81.5)486 (82.4)508 (86.1)515 (87.3)
Errors ¾ 10 šF462 (78.3)570 (96.6)576 (97.6)578 (98.0)582 (98.6)

Table 2: Errors in forecasts (forecast - observation) by 5 šF bins (except for perfect forecast) and number (percentage) of forecasts within 5 šF and 10 šF.

Observations

a)¾-25-20-15-10-505101520„25Np(f )
¾-255100000000061.0
-203600000000091.5
-1544930000000203.4
-10239186400000427.1
-5012153621310007913.4
Forecasts000172912249800021636.6
50110340612621013522.9
10000003182810106010.2
15000000121022172.9
200000000003250.8
„250000000001010.2
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7298

Observations

b)¾-25-20-15-10-505101520„25Np(f )
¾-2564000000000101.7
-2056100000000122.0
-15221130100000193.2
-101152316300000498.3
-50241335719000013422.7
Forecasts00113168751700016628.1
50001724522620011219.0
100000031925700549.2
1500000117931223.7
2000000000442101.7
„250000000001120.3
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7259

Table 3: Joint distribution of observed temperature changes and forecasts. N is total number of forecasts or observations in that bin. p(f ) [p(x )] is the marginal probability of that forecast [observation] in per cent. Number at lower right is number of forecasts in the same bin as the observed temperature change. a) LFM MOS. b) NGM MOS. c) CON. d) NWSFO

Observations

c)¾-25-20-15-10-505101520„25Np(f )
¾-254200000000061.0
-2064000000000101.7
-15361030000000223.7
-10128205200000386.4
-50121642433000010718.1
Forecasts001232311954800021035.6
50001424592120011118.8
10000002163410206410.8
1500000002912142.4
200000000014161.0
„250000000001120.3
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7306

Observations

d)<-25-20-15-10-505101520>25Np(f )
¾-2583000000000111.9
-2046000000000101.7
-1513910000000142.4
-101310205000000396.6
-5012143916200007412.5
Forecasts000172413943400021836.9
50001430652220012421.0
1000002522326206911.7
15000000071221223.7
200000000024281.4
„250000000000110.2
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7335

Table 3: Joint distribution of observed temperature changes and forecasts. N is total number of forecasts or observations in that bin. p(f ) [p(x )] is the marginal probability of that forecast [observation] in per cent. Number at lower right is number of forecasts in the same bin as the observed temperature change. a) LFM MOS. b) NGM MOS. c) CON. d) NWSFO

Observations

a)¾-25-20-15-10-505101520„25Np(f)
¾-2583.316.7.0.0.0.0.0.0.0.0.061.0
-2033.366.7.0.0.0.0.0.0.0.0.091.5
-1520.020.045.015.0.0.0.0.0.0.0.0203.4
-104.87.121.442.914.39.5.0.0.0.0.0427.1
-5.01.32.519.045.626.63.81.3.0.0.07913.4
Forecasts0.0.0.53.213.456.522.73.7.0.0.021636.6
5.0.7.7.02.229.645.219.31.5.7.013522.9
10.0.0.0.0.05.030.046.716.71.7.06010.2
15.0.0.0.0.0.05.911.858.811.811.8172.9
20.0.0.0.0.0.0.0.0.060.040.050.8
„25.0.0.0.0.0.0.0.0.0100.0.010.2


Observations

b)¾-25-20-15-10-505101520„25Np(f)
¾-2560.040.0.0.0.0.0.0.0.0.0.0101.7
-2041.750.08.3.0.0.0.0.0.0.0.0122.0
-1510.510.557.915.8.05.3.0.0.0.0.0193.2
-102.02.010.246.932.76.1.0.0.0.0.0498.3
-5.01.53.09.726.153.06.7.0.0.0.013422.7
Forecasts0.0.6.61.89.652.430.74.2.0.0.016628.1
5.0.0.0.96.321.446.423.21.8.0.011219.0
10.0.0.0.0.05.635.246.313.0.0.0549.2
15.0.0.0.0.04.54.531.840.913.64.5223.7
20.0.0.0.0.0.0.0.040.040.020.0101.7
„25.0.0.0.0.0.0.0.0.050.050.02.3

Table 4: Conditional probability of observations given forecasts and marginal distribution of forecasts. Column and rows are 5 šF temperature bins centered on number in heading. N [p(f)] is total number (marginal probability) of cases in respective forecast bin. a) LFM MOS. b) NGM MOS. c) CON. d) NWSFO.


Observations

c)¾-25-20-15-10-505101520„25Np(f)
¾-2566.733.3.0.0.0.0.0.0.0.0.061.0
-2060.040.0.0.0.0.0.0.0.0.0.0101.7
-1513.627.345.513.6.0.0.0.0.0.0.0223.7
-102.65.321.152.613.25.3.0.0.0.0.0386.4
-5.0.91.915.039.340.22.8.0.0.0.010718.1
Forecasts0.0.51.01.411.056.725.73.8.0.0.021035.6
5.0.0.0.93.621.653.218.91.8.0.011118.8
10.0.0.0.0.03.125.053.115.63.1.06410.8
15.0.0.0.0.0.0.014.364.37.114.3142.4
20.0.0.0.0.0.0.0.016.766.716.761.0
„25.0.0.0.0.0.0.0.0.050.050.020.3

Observations

d)<-25-20-15-10-505101520>25Np(f)
¾-2572.727.3.0.0.0.0.0.0.0.0.0111.9
-2040.060.0.0.0.0.0.0.0.0.0.0101.7
-157.121.464.37.1.0.0.0.0.0.0.0142.4
-102.67.725.651.312.8.0.0.0.0.0.0396.6
-5.01.42.718.952.721.62.7.0.0.0.07412.5
Forecasts0.0.0.53.211.063.819.71.8.0.0.021837.0
5.0.0.0.83.224.252.417.71.6.0.012421.0
10.0.0.0.02.97.231.946.48.72.9.06911.7
15.0.0.0.0.0.0.031.854.59.14.5223.7
20.0.0.0.0.0.0.0.025.050.025.081.4
„25.0.0.0.0.0.0.0.0.0.0100.010.2

Table 4: Conditional probability of observations given forecasts and marginal distribution of forecasts. Column and rows are 5 šF temperature bins centered on number in heading. N [p(f)] is total number (marginal probability) of cases in respective forecast bin. a) LFM MOS. b) NGM MOS. c) CON. d) NWSFO.


Observations

a)¾-25-20-15-10-505101520„25
¾-2535.76.3.0.0.0.0.0.0.0.0.0
-2021.437.5.0.0.0.0.0.0.0.0.0
-1528.625.040.97.0.0.0.0.0.0.0.0
-1014.318.840.941.98.12.1.0.0.0.0.0
-5.06.39.134.948.611.12.31.5.0.0.0
Forecasts0.0.04.516.339.264.237.112.3.0.0.0
5.06.34.5.04.121.146.240.09.112.5.0
10.0.0.0.0.01.613.643.145.512.5.0
15.0.0.0.0.0.0.83.145.525.050.0
20.0.0.0.0.0.0.0.0.037.550.0
„25.0.0.0.0.0.0.0.0.012.5.0
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7

Observations

b)¾-25-20-15-10-505101520„25
¾-2542.925.0.0.0.0.0.0.0.0.0.0
-2035.737.54.5.0.0.0.0.0.0.0.0
-1514.312.550.07.0.0.5.0.0.0.0.0
-107.16.322.753.521.61.6.0.0.0.0.0
-5.012.518.230.247.337.46.8.0.0.0.0
Forecasts0.06.34.57.021.645.838.610.8.0.0.0
5.0.0.02.39.512.639.440.09.1.0.0
10.0.0.0.0.01.614.438.531.8.0.0
15.0.0.0.0.0.5.810.840.937.525.0
20.0.0.0.0.0.0.0.018.250.050.0
„25.0.0.0.0.0.0.0.0.012.525.0
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7

Table 5: Conditional probability of forecasts given observations. Column and rows are 5 šF temperature bins centered on number in heading. N [p(x)] is total number (marginal distribution) of observations in each respective bin. a) LFM MOS. b) NGM MOS. c) CON. d) NWSFO.
Observations

c)¾-25-20-15-10-505101520„25
¾-2528.612.5.0.0.0.0.0.0.0.0.0
-2042.925.0.0.0.0.0.0.0.0.0.0
-1521.437.545.57.0.0.0.0.0.0.0.0
-107.112.536.446.56.81.1.0.0.0.0.0
-5.06.39.137.256.822.62.3.0.0.0.0
Forecasts0.06.39.17.031.162.640.912.3.0.0.0
5.0.0.02.35.412.644.732.39.1.0.0
10.0.0.0.0.01.112.152.345.525.0.0
15.0.0.0.0.0.0.03.140.912.550.0
20.0.0.0.0.0.0.0.04.550.025.0
„25.0.0.0.0.0.0.0.0.012.525.0
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7

Observations

d)¾-25-20-15-10-505101520„25
¾-2557.118.8.0.0.0.0.0.0.0.0.0
-2028.637.5.0.0.0.0.0.0.0.0.0
-157.118.840.92.3.0.0.0.0.0.0.0
-107.118.845.546.56.8.0.0.0.0.0.0
-5.06.39.132.652.78.41.5.0.0.0.0
Forecasts0.0.04.516.332.473.232.66.2.0.0.0
5.0.0.02.35.415.849.233.89.1.0.0
10.0.0.0.02.72.616.749.227.325.0.0
15.0.0.0.0.0.0.010.854.525.025.0
20.0.0.0.0.0.0.0.09.150.050.0
„25.0.0.0.0.0.0.0.0.0.025.0
N1416224374190132652284
p(x)2.42.73.77.312.532.222.411.03.71.40.7

Table 5: Conditional probability of forecasts given observations. Column and rows are 5 šF temperature bins centered on number in heading. N [p(x)] is total number (marginal distribution) of observations in each respective bin. a) LFM MOS. b) NGM MOS. c) CON. d) NWSFO.


LFMNGMCONNWSFOOBS
Mean.30-.47-.08.64.15
Standard deviation7.568.417.608.179.17
Correlation with observations.87.88.90.91
a-.17.60.23-.51
b1.06.961.091.02

Table 6: Parameters associated with linear regression model for expected value of observations given forecast.

COOLING
N = 139LFMNGMCONNWSFO
ME2.451.632.242.78
MAE3.63 (5.35)3.30 (-4.14)3.19 (-7.90)3.44
RMSE4.73 (4.18)4.40 (-3.21)4.23 (-7.28)4.54
WARMING
N = 219LFMNGMCONNWSFO
ME-1.95-1.86-2.08-1.15
MAE3.20 (17.40)3.31 (20.14)3.01 (12.27)2.64
RMSE3.99 (15.95)4.09 (17.86)3.70 (9.28)3.36


Table 7: Simple statistics as in Table 1, stratified by observed cooling of 3-17 šF and observed warming of 3-17 šF. Numbers in parenthesis are percentage improvement by unadjusted NWSFO forecast over guidance product. Negative values indicate guidance performed better in this parameter. Number of forecasts indicated at upper left.


COOLING
N = 139LFMNGMCONNWSFO
ME2.451.632.242.29
MAE3.63 (12.24)3.30 (3.44)3.19 (-0.05)3.19
RMSE4.73 (10.14)4.40 (3.22)4.23 (-0.60)4.25
WARMING
N = 219LFMNGMCONNWSFO
ME-1.95-1.86-2.08-1.64
MAE3.20 (17.40)3.31 (20.14)3.01 (12.27)2.86
RMSE3.99 (15.95)4.09 (17.86)3.70 (9.28)3.55

Table 8: Same as Table 7, except for adjusted NWSFO forecast (cooled by 0.49 šF).


COOLING
N = 30LFMNGMCONNWSFO
ME6.834.736.073.47
MAE7.43 (30.94)6.13 (16.30)6.80 (24.51)5.13
RMSE9.00 (29.10)7.88 (19.03)8.32 (23.28)6.38
WARMING
N = 12LFMNGMCONNWSFO
ME-5.25-2.00-3.83-3.75
MAE5.75 (17.39)3.83 (-23.91)4.83 (1.72)4.75
RMSE7.21 (23.46)4.30 (-28.22)5.74 (3.99)5.52


Table 9: Same as Table 7, except for extreme temperature changes (¾-18 šF and „18 šF).

ForecastError
DateCONNWSFOObservedCONNWSFONWSFO
Improvement
2-Feb-93-65-4-29-7
22-Feb-93-15-217-6
4-Feb-94-11-5-1106-6
19-Feb-9428-3511-6
27-Mar-940-600-6-6
10-Mar-942514223-8-5
14-Jan-934-231-5-4
30-Dec-93061-15-4
26-Sep-933-312-4-2
5-Nov-93-28-36-313-5-2
9-Dec-9381611-35-2
6-Jan-94-16-27-226-51
31-Jan-9391513-422
2-Jul-94-9-3-5-422
9-Jan-93-253-523
24-Nov-93-31-39-376-24
9-Jan-942108-624
24-Feb-94243331-725
15-Feb-93-6-12-13716
16-Feb-93-3-9-12936
29-Oct-93-27-21-20-7-16
21-Feb-94-3-11-107-16
9-Mar-945-1-1606
27-Dec-93-16-9-9-707
25-Feb-94-15-25-3015510
8-Feb-942-9-1820911

Table 10: CON and NWSFO forecasts and errors for 26 days on which NWSFO and CON disagreed by more than 5 šF. "NWSFO Improvement" is the difference in the error of the two statistics, with the sign convention such that positive values indicate lower error for NWSFO.