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NRL Monterey, Marine Meteorology Division
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NRL Monterey, Marine Meteorology Division
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| COAMPS SOUTHERN CALIFORNIA PRECIP FORECASTS A well defined cold front moved through the Southern California area on 26 January 2001. A series of GOES IR images are shown to illustrate the progression of the cold front through the area. The cumulative precipitation forecasts from the inner 6 km nested COAMPS TAMS/RT run produced at NRL Monterey are shown to illustrate the COAMPS skill in precipitation forecasts for this frontal system. Selected station weather observations and 24 hour precipation totals are provided as verification factors. |
| Rainfall totals for January 26th collected for the area included: Downtown LAX 0.71, Imperial Beach 0.59, and San Diego International 0.60 inches. Rain began at LAX International at 26/04:50AM PST, and the first report of rain at San Diego International was at 26/10:25AM PST. |
| Figure 1 GOES IR 26/1000Z 26/02:00AM PST | Figure 2 GOES IR 26/1200Z 26/04:00AM PST | Figure 3 GOES IR 26/1400Z 26/06:00AM PST | |
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| Figures 1 through 3 show a four hour sequence, from 26/02:00AM PST through 26/06:00AM, of IR images that illustrate the progression of the frontal cloud band. The "FLICKER" button provides for animation of these three images. The reported start of rain time at LAX was just minutes before the Figure 2 time. | |||
| Figure 4 GOES IR 26/1600Z 26/08:00AM PST | Figure 5 GOES IR 26/1800Z 26/10:00AM PST | Figure 6 GOES IR 26/2000Z 26/12:00 Noon PST | |
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| Figures 4 through 6 continue the IR sequence for an additional six hours through 26/12:00 Noon PST. The reported start of rain at San Diego was at about 35 minutes before the Figure 5 time. | |||
| Figure 7 GOES IR 26/2200Z 26/02:00PM PST |
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| Figure 7 continues the IR image coverage to 26/02:00PM. |
| Figure 8 San Diego Meteogram 26/1200Z to 27/1200Z 26/04:00AM to 27/04:00AM PST | Figure 9 Riverside Meteogram 26/1200Z to 27/1200Z 26/04:00AM to 27/04:00AM PST |
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| The COAMPS 6km mesh based Meteograms for San Diego and Riverside are shown in Figures 8 and 9. Note the close correspondence between forecast and first reported rain times (SAN 26/10:25AM PST/1825Z and LAX 26/04:50AM/1250Z). | |
| Figure 10 COAMPS Cumulative Precip tau 1 VT 26/05:00AM PST | Figure 11 COAMPS Cumulative Precip tau 4 VT 26/08:00AM PST | Figure 12 COAMPS Cumulative Precip tau 7 VT 26/11:00AM PST | |
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| The COAMPS inner mesh (6km resolution) Cumulative Precip forecasts starting at tau 1, VT 26/1300Z (26/05:00AM PST) Figure 10, through tau 7, 26/1900Z (26/11:00AM PST) Figure 12, show the COAMPS forecast of precipitation cumulation with the frontal progression. Note that as time progresses, and the precipitation producing weather pattern moves through the area, the changes in the Cumulative Precip patterns are primarily seen in the leading portions of the precipitation patterns. | |||
| Figure 13 COAMPS Cumulative Precip tau 6 VT 26/10:00AM PST | Figure 14 COAMPS Cumulative Precip tau 8 VT 26/12:00Noon PST | Figure 15 COAMPS Cumulative Precip tau 10 VT 26/02:00PM PST | |
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| Figures 13 through 15 are shown to illustrate the precipitation cumulation around the San Diego area for the 26/10:00AM (26/18Z) through 26/02:00PM (26/22Z) period of time. | |||
| Figure 16 COAMPS Cumulative Precip tau 12 VT 26/04:00PM PST | Figure 17 COAMPS Cumulative Precip tau 18 VT 26/10:00PM PST | Figure 18 COAMPS Cumulative Precip tau 24 VT 27/04:00AM PST | |
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| Figures 16 through 18 provide an additional 12 hours of COAMPS Cumulative Precip forecasts for the 26/04:00PM (27/00Z) through 25/04:00AM (27/12Z) period. Additional precipitation amounts during this period are likely primarily due to post-frontal shower activity. | |||
Author: Ron Englebretson Last Updated: Tue Dec 10 16:14:22 2002 Produced by: The Composer (Ver: 1.1.2 ) |
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