Tehuantepecer depicted by SPoRT/SERVIR WRF model runs

Strong winds have been occurring for the last several days in the Gulf of Tehuantepec of the eastern Pacific Ocean, to the south of eastern Mexico.  These strong gap winds result from cool high pressure systems that surge southward through the western Gulf of Mexico, with the air funneled through the relatively lower elevation of Chivela Pass in eastern Mexico (Fig. 1).  These high winds have been nicely depicted by the Weather Research and Forecasting (WRF) model runs produced through a collaboration between SPoRT and NASA/SERVIR, as shown by the 30-h forecast maximum hourly 10-m wind speed in Fig. 2, valid on 1200 UTC 12 November.  A corresponding image of WindSat retrieved winds is shown in Fig. 3 for roughly the same time as the WRF model forecast.

The SPoRT/SERVIR WRF model forecasts over the Caribbean and Central America are unique in that the model runs are generated daily in real-time using cloud computing resources.  The model runs are initialized at 0600 UTC, ingest SPoRT sea surface temperatures in the initial conditions, and are integrated out to 48 hours.  The team is working to migrate the model output to a real-time web map service.

This latest surge of cold air impacting the U.S. Deep South today will continue unabated into the Gulf of Tehuantepec over the next day or so.  Today’s SPoRT/SERVIR WRF model run suggests a substantial increase in the wind speeds to over 20 m/s by 0600 UTC 14 November (Fig. 4).  Winds are forecast to exceed 20 m/s from about 1500 UTC 13 November through 1200 UTC 14 November.   The National Hurricane Center’s Tropical Analysis and Forecast Branch put out an experimental graphic indicating this expected increase in wind speeds and accompanying high seas in the eastern Pacific Ocean (Fig. 5).

Figure 1.  Topography in Eastern Mexico leading to strong gap winds in the Gulf of Tehuantepec.

Figure 1. Topography in Eastern Mexico leading to strong gap winds in the Gulf of Tehuantepec.
Image credit: http://www.wunderground.com/blog/24hourprof/tehuantepecer.

Figure 2.  Thirty-hour forecast of maximum hourly 10-m wind speed (m/s) from SPoRT/SERVIR WRF model run, valid at 1200 UTC 12 November 2013.

Figure 2. Thirty-hour forecast of maximum hourly 10-m wind speed (m/s) from SPoRT/SERVIR WRF model run, valid at 1200 UTC 12 November 2013.

Figure 3.  WindSat image of wind vector valid 1200 UTC 12 November 2013, courtesy of the Naval Research Laboratory.

Figure 3.  Image of retrieved WindSat winds valid 1225 UTC 12 November 2013, courtesy of the Naval Research Laboratory.

Figure 4.  Twenty-four hour forecast of maximum hourly 10-m wind speeds from the SPoRT/SERVIR WRF model, valid 0600 UTC 14 November 2013.

Figure 4. Twenty-four hour forecast of maximum hourly 10-m wind speeds from the SPoRT/SERVIR WRF model, valid 0600 UTC 14 November 2013.

Fig. 5.  Experimental Graphical Forecast produced by NHC's Tropical Analysis and Forecast Branch, valid through 0000 UTC 14 November 2013.

Fig. 5. Experimental Graphical Forecast produced by NHC’s Tropical Analysis and Forecast Branch, valid through 0000 UTC 14 November 2013.

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