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WRF : “Great North Run”and COPS

Ralph Burton, NCAS (Leeds)Alan Gadian, NCAS (Leeds)Alison Coals, NCAS (Leeds)

http://www.ncas.ac.uk

“Operational use” : a 1-km forecast model for the north of the UK

“Research use” COPS (Convective and Orographically-induced Precipitation Study)

WRF: examples of use

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WRF GNR

Great North Run

3 nests with feedbackbetween nests;

81 vertical levels;

Domains are356x196 (@9km)319x322 (@3km)391x328 (@1km)

Inner domain coversfrom Berwickto Nottingham

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WRF GNR

A useful exercise for PhD students / Postdocs

In Leeds, every Thursday there is a “Chatmosphere”(students and staff discuss the forecast, interesting weather, etc.)

Get students to perform a WRF forecast for the North of England

Takes approx 2 x 2hr teaching sessions for students to be able to do the forecast independently

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WRF GNR

Ongoing WRF verification / evaluation

Each week a set of forecast plots is produced,allowing an ongoing evaluation of WRFperformance

Forecast plots are archived

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WRF GNR

Routinely, every Wednesday WRF is run, andthe plots produced on Thursday morning.

Plots produced, for T=0, 1, 2, ..., 60:

Sea – level pressure, surface temps and winds

Precipitation

Skew-T for Leeds-Bradford Airport

850mb theta_e

1000-500mb thickness

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WRF GNR

SLP, surface winds and temps Precip in last hour

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WRF GNR: comparison with satellite data

23/02/08:

12Z

T+60

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23/02/08:

12Z

T+60

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WRF GNR: comparison with satellite data

23/02/08:

12Z

T+60

Cloud water mixing ratio = 0.1g / Kg

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Cloud water mixing ratio = 1g / Kg

23/02/08: 12Z : T+60

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WRF GNR

Skew-T for 23/02/08 12Z: T+60: Nottingham

WRFObserved

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WRF GNR: 1km results

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WRF GNR: 1km results

23/02/08:

12Z

(T+60)

http://www.ncas.ac.uk

“Operational use” : a 1-km forecast model for the north of the UK

“Research use” COPS (Convective and Orographically-induced Precipitation Study)

WRF: examples of use

http://www.ncas.ac.uk

COPS

Convective and Orographically-induced Precipitation Study

http://www.cops2007.de

http://www.ncas.ac.uk

COPS WRF

Note the location and orientation (SW-NEish) of the storm cloud

15th July: isolated deep convective cloud

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WRF COPS

3 Domains:

300 x 300

301 x 301

199 x 199

(6.3km, 2.1km, 700m)

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COPS WRF

Upward moisture flux at surface; 10m wind vectors

15/07/07 15Z

Strong convergence; relativelyhigh upward moisture flux “upwind”of the convergence line

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COPS WRF

10m wind vectors over orography with cross-section of Wover the convergence line; 15Z

+ve vertical velocities not appreciable above 5km

Wave-like features

+ve W-ve W

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COPS WRF

... but: no cloud in the WRF run!

We think we know why this, is and work is still ongoing.

Summary

WRF is used at the University of Leeds in a routineforecast manner

WRF is being used to investigate the 15th July cloud