A Cold Bias in the MRF

 

 

            The current operational MRF has been observed to have a cold bias in the Northern Hemisphere mid-latitudes the last few months.  Before the introduction of prognostic cloud liquid water in August 2001, the MRF had a warm bias over the Northern Hemisphere mid-latitude continents in summer.  This page documents the cold bias of the MRF and examines its development for two periods, one with a ridge over the east coast of the United States (Nov. 26-Dec.16, 2001) and one with a more characteristic trough over the east coast (Dec. 24, 2001-Jan. 8, 2002). 

 

December Drifts

 

            This section examines the evolution of error in forecasts originating in December 2001.  Forecasts every 24 hours from the 000 UT analyses for December to the 360-hr forecasts originating in December are examined.  The verifying analyses for each forecast length are subtracted to determine the error drift.

 

Temperature

 

Area-averaged drifts

 

Global mean

30-60N

30-60N land

 

Longitude-forecast length cross-sections

 

40N

 

850 hPa

900 hPa

925 hPa

 

Latitude-forecast length cross-sections

 

0-90N

 

115E

110W

80W

 

Pressure-forecast length cross-sections

 

40N

 

115E

110W

80W

 

850 hPa surface contour

 

Height

 

Area-averaged drifts

 

Global mean

30-60N

30-60N land

 

Longitude-forecast length cross-sections

 

40N, 500 hPa

 

Latitude-forecast length cross-sections

 

0-90N

 

120E

135W

75W

 

Pressure-forecast length cross-sections

 

40N

 

120E

135W

75W

 

 

Longitude-time diagrams

40N, 0-360

500 hPa Heights

 

Analyses (zonal mean out)

Forecasts (zonal mean out)

Errors (zonal mean in)

 

 

6-hr forecasts

For 1-dy forecasts

 

1-dy forecasts

For 2-dy forecasts

 

2-dy forecasts

For 3-dy forecasts

3-dy forecasts

3-dy forecasts

For 4-dy forecasts

 

4-dy forecasts

For 5-dy forecasts

5-dy forecasts

5-dy forecasts

For 7-dy forecasts

7-dy forecasts

7-dy forecasts

For 8-dy forecasts

 

8-dy forecasts

For 10-dy forecasts

10-dy forecasts

10-dy forecasts

For 15-dy forecasts

15-dy forecasts

15-dy forecasts

 

925 hPa Temperatures

 

Analyses (zonal mean out)

Forecasts (zonal mean out)

Errors (zonal mean in)

 

 

6-hr forecasts

For 1-dy forecasts

 

1-dy forecasts

For 2-dy forecasts

 

2-dy forecasts

For 3-dy forecasts

3-dy forecasts

3-dy forecasts

For 4-dy forecasts

 

4-dy forecasts

For 5-dy forecasts

5-dy forecasts

5-dy forecasts

For 7-dy forecasts

7-dy forecasts

7-dy forecasts

For 8-dy forecasts

 

8-dy forecasts

For 10-dy forecasts

10-dy forecasts

10-dy forecasts

For 15-dy forecasts

15-dy forecasts

15-dy forecasts

 

40N, 180-360

500 hPa Heights

 

Analyses (zonal mean out)

Forecasts (zonal mean out)

Errors (zonal mean in)

 

 

1-dy forecasts

 

 

3-dy forecasts

For 5-dy forecasts

5-dy forecasts

5-dy forecasts

For 10-dy forecasts

10-dy forecasts

10-dy forecasts

For 15-dy forecasts

15-dy forecasts

15-dy forecasts

 

925 hPa Temperatures

 

Analyses (zonal mean out)

Forecasts (zonal mean out)

Errors (zonal mean in)

For 5-dy forecasts

5-dy forecasts

5-dy forecasts

 

Nov. 26-Dec. 16, 2001

 

500hPa Height

 

Climatology for December

 

Time-means (zonal mean out)

Forecast error (zonal mean in)

Fcst. diff. (zonal mean in)

Analyses

6 hour-anl

 

1 day forecasts

1 day-anl

 

2 day forecasts

2 day-anl

2 day-1 day

3 day forecasts

3 day-anl

3 day-2 day

4 day forecasts

4 day-anl

4 day-3 day

5 day forecasts

5 day-anl

5 day-4 day

7 day forecasts

7 day-anl

7 day-5 day

8 day forecasts

8 day-anl

8 day-7 day

10 day forecasts

10 day-anl

10 day-8 day

15 day forecasts

15 day-anl

15 day-10 day

 

925hPa Temperature

 

Climatology for December

 

Time-means (zonal mean out)

Forecast error (zonal mean in)

Fcst. diff. (zonal mean in)

Analyses

6 hour-anl

 

 

1 day-anl

 

 

2 day-anl

2 day-1 day

 

3 day-anl

3 day-2 day

 

4 day-anl

4 day-3 day

5 day forecasts

5 day-anl

5 day-4 day

 

7 day-anl

7 day-5 day

 

8 day-anl

8 day-7 day

10 day forecasts

10 day-anl

10 day-8 day

15 day forecasts

15 day-anl

15 day-10 day

 

Surface Fluxes

 

Precipitation

 

0-6 hour

Day 3–day 1

0-24  hour

Day 5–day 1

48-72 hour

Day 5–day 3

96-120 hour

Day 10–day 1

216-240 hour

Day 15–day 1

336-360 hour

Day 15–day 10

 

Sensible heat

 

0-6 hour

 

0-24  hour

Day 3–day 1

48-72 hour

Day 5–day 1

96-120 hour

Day 10–day 1

216-240 hour

Day 15–day 1

336-360 hour

Day 15–day 10

 

Latent heat

 

0-6 hour

 

0-24  hour

Day 3–day 1

48-72 hour

Day 5–day 1

96-120 hour

Day 10–day 1

216-240 hour

Day 15–day 1

336-360 hour

Day 15–day 10

 

Net short wave

 

0-6 hour

 

0-24  hour

Day 3–day 1

48-72 hour

Day 5–day 1

96-120 hour

Day 10–day 1

216-240 hour

Day 15–day 1

336-360 hour

Day 15–day 10

 

Net long wave

 

0-6 hour

 

0-24  hour

Day 3–day 1

48-72 hour

Day 5–day 1

96-120 hour

Day 10–day 1

216-240 hour

Day 15–day 1

336-360 hour

Day 15–day 10

 

Net heat flux

 

0-6 hour

 

0-24  hour

Day 3–day 1

48-72 hour

Day 5–day 1

96-120 hour

Day 10–day 1

216-240 hour

Day 15–day 1

336-360 hour

Day 15–day 10

 

Dec.24, 2001-Jan. 8, 2002

 

500hPa Height

 

Climatology for December

 

Time-means (zonal mean out)

Forecast error (zonal mean in)

Fcst. diff. (zonal mean in)

Analyses

6 hour-anl

 

 

1 day-anl

 

 

2 day-anl

2 day-1 day

3 day forecasts

3 day-anl

3 day-2 day

 

4 day-anl

4 day-3 day

5 day forecasts

5 day-anl

5 day-4 day

7 day forecasts

7 day-anl

7 day-5 day

 

8 day-anl

 

10 day forecasts

10 day-anl

10 day-7 day

15 day forecasts

15 day-anl

15 day-10 day

 

925hPa Temperature

 

Climatology for December

 

Time-means (zonal mean out)

Forecast error (zonal mean in)

Fcst. diff. (zonal mean in)

Analyses

6 hour-anl

 

 

1 day-anl

 

 

2 day-anl

2 day-1 day

3 day forecasts

3 day-anl

3 day-2 day

 

4 day-anl

4 day-3 day

5 day forecasts

5 day-anl

5 day-4 day

7 day forecasts

7 day-anl

7 day-5 day

 

8 day-anl

 

10 day forecasts

10 day-anl

10 day-7 day

15 day forecasts

15 day-anl

15 day-10 day