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Gulf Surges, the Diurnal Cycle, and Convective Outflows as Revealed by the NCAR ISSs in NAME

Gulf Surges, the Diurnal Cycle, and Convective Outflows as Revealed by the NCAR ISSs in NAME. Richard H. Johnson, Peter J. Rogers, Paul E. Ciesielski, Brian D. McNoldy, and Richard K. Taft. Colorado State University.

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Gulf Surges, the Diurnal Cycle, and Convective Outflows as Revealed by the NCAR ISSs in NAME

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  1. Gulf Surges, the Diurnal Cycle, and Convective Outflows as Revealed by the NCAR ISSs in NAME Richard H. Johnson, Peter J. Rogers, Paul E. Ciesielski, Brian D. McNoldy, and Richard K. Taft Colorado State University Acknowledgments: NSF, NOAA, NCAR ATD staff, and numerous students who worked at ISS sites

  2. NCAR Integrated Sounding System (ISS) • Vaisala GPS sounding system • Enhanced surface observing station • 915 MHz Doppler clear-air wind profiling radar • Radio Acoustic Sounding System (RASS) • 3 ISSs used in NAME • 1 GLASS sounding system ISS Trailer, Los Mochis

  3. 3 ISSs 1 GLASS PUERTO PEÑASCO BAHIA KINO LOS MOCHIS LORETO NAME SOUNDING NETWORK

  4. Moisture surges and tropical waves, cyclones PRECIPITABLE WATER (105-115°W) N GULF S2(IOP3) S1 (IOP2) (IOP10) HURR JAVIER HURR HOWARD TS GEORGETTE TS BLAS HURR FRANK TS AGATHA HURR DARBY HURR ISIS HURR CELIA May June July Aug Sep 2004 (NCEP Operational Analysis)

  5. 700-hPa V WIND (15-25°N) Easterly Waves During NAME EOP May CENTRAL GULF Jun 2004 Jul BLAS CELIA DARBY Aug FRANK GEORGETTE HOWARD ISIS Sep JAVIER

  6. 1004 L ●` YUMA Heat Low ● MAZATLAN TROPICAL STORM BLAS

  7. 13 JULY V N GULF QuikSCAT Winds S GULF HURR FRANK TS GEORGETTE TS BLAS HURR JAVIER HURR HOWARD HURR DARBY?

  8. PUERTO PEÑASCO BAHIA KINO LOS MOCHIS BLAS 13 July 2004 0024-0824Z

  9. LOS MOCHIS ISS ●

  10. SURGE MIDNIGHT NOON GUST FRONT 4-hPa rise

  11. km 00 UTC 05 10 15 20 GUST FRONT SURGE PEAK

  12. ● BAHIA KINO ISS

  13. SURGE MIDNIGHT NOON 3-hPa rise 7 hPa rise, but over longer period

  14. ● PUERTO PEÑASCO ISS

  15. SURGE MIDNIGHT NOON GUST FRONTS 3.5-hPa rise

  16. km (RASS shut down at night due to noise impact on local populace) surge

  17. SURGE CONTINUES NEXT DAY, PEAKING AT NIGHT MIDNIGHT NOON 4-hPa additional rise

  18. MIDNIGHT NOON PRESSURE MAXIMUM, 8 hPa INCREASE OVER 2 DAYS

  19. Puerto Peñasco Bahia Kino Los Mochis 7-8 hPa rise Pressure rise signature progresses up the Gulf (8-10 h from Los Mochis to Puerto Peñasco) 20-25 m s-1 propagation speed! Pressure signature and speed characteristic of an internal bore or mixed Kelvin wave–bore(e.g., Ralph et al. 2000)

  20. Altair 12/20 – 13/04Z

  21. Puerto Peñasco 13/12 – 13/18Z

  22. GULF-// WINDS PEAK WINDS NEAR THE SURFACE IN THE NORTH ● ● ● ● ● …PEAK WINDS ELEVATED IN THE SOUTH

  23. COOLING ASSOCIATED WITH SURGES… ● ● ● ● ● • PRINCIPALLY CONFINED BELOW 700 hPa • LASTS FOR 3-4 DAYS • ELEVATED IN S FOR FIRST SURGE

  24. Rain moved northward along coastal plain and into AZ with surge 24-h totals, 12-14 July

  25. PP EOP-MEAN LOW-LEVEL WIND DIURNAL CYCLE (7 JUL – 14 AUG) Puerto Penasco UTC MIDNIGHT NOON Strong low-level jet at PP, much weaker at BK, absent at LM (Douglas 1995) BK Bahia Kino LM Sea breezes Los Mochis Weak land breezes, nocturnal offshore convection near S-Pol

  26. S-POL RADAR 3 Aug 2004 1000-1330 UTC NOAA-ETL PROFILER

  27. Summary and Conclusions • ISSs successfully documented many aspects of NAM along Gulf of California, including characteristics of surges • July 13 surge associated with TS BLAS, preceded by downdraft outflows from SMO convection • Pressure rises 3-4 hPa over 8-10 h period of surge, followed by additional 4 hPa rise over next 1-2 days (2-3°C surface temperature drop); initial P-rise signal moved rapidly up Gulf (20-25 m s-1)  internal bore, mixed Kelvin wave-bore? (awaiting more data) • Peak surge winds on 13 July descend from 1.2 km AGL at LM and BK, to near 700 m at PP, maximum wind 20 m s-1 at Puerto Penasco; convective outflows are shallower (peak winds near 300 m)

  28. Summary and Conclusions (cont) • Surge on 13 July led to increased TPW and rainfall over southwestern US • Diurnal cycle of PBL winds varies from south to north; prominent nocturnal LLJ in north, absent in south; prominent afternoon sea breezes at BK and LM; weak land breezes at BK and LM, coastal offshore convection near S-Pol • Results are preliminary; further analysis awaits additional surface, pibal, and sounding data

  29. (Ralph et al. 2000)

  30. (Ralph et al. 2000) (Nuss et al. 2000)

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