Eyad Atallah

Interests

Teaching

Synoptic/Dynamic MeteorologyClimate Change and WeatherScience CommunicationTruth and Science

Research

Science CommunicationSevere Precipitation Events

Courses

Scholarly Contributions

Books

• Atallah, E. H., & Bosart, L. F. (2004). Precipitation distribution associated with landfalling tropical cyclones.

Journals/Publications

• Low, Y., Gyakum, J. R., & Atallah, E. (2022). Extreme Winter Precipitation Regimes in Eastern North America: Synoptic-Scale and Thermodynamic Environments. Monthly Weather Review, 150(7), 1833-1850.
• Melamed-Turkish, K. .., Milrad, S., Gyakum, J., & Atallah, E. (2022). A Conceptual Synoptic Model Approach to the Development of a Precipitation Climatology as Applied to Montreal, Quebec. Weather and Forecasting, 37(7), 1221-1238.
• Atallah, E., Gyakum, J. R., Melamed-Turkish, K., & Milrad, S. M. (2021). A dynamic approach to the development of a precipitation climatology as applied to Montreal, Québec. Weather and Forecasting, 37(7).
• MCCRAY, C. D., GYAKUM, J. R., & ATALLAH, E. H. (2021). Synoptic-dynamic and airmass characteristics distinguishing long- And short-duration freezing rain events in the south-central united states. Monthly Weather Review, 149(5), 1287-1304.
• Atallah, E., McCray, C., & Gyakum, J. (2020). Regional Thermodynamic Characteristics Distinguishing Long- and Short-Duration Freezing Rain Events over North America. Weather and Forecasting, 35(2), 657-671. doi:https://doi.org/10.1175/WAF-D-19-0179.1
• McCray, C. D., Gyakum, J. R., & Atallah, E. H. (2020). Regional thermodynamic characteristics distinguishing long-and short-duration freezing rain events over North America. Weather and Forecasting, 35(2), 657-671.
• Atallah, E., Milrad, S., Gyakum, J., Isphording, R., & Klepatzki, J. (2019). The Extreme Precipitation Index (EPI): A Coupled Dynamic–Thermodynamic Metric to Diagnose Midlatitude Floods Associated with Flow Reversal. Weather and Forecasting, 34(5), 1257-1276. doi:https://doi.org/10.1175/WAF-D-18-0156.1
• Bowley, K. A., Gyakum, J. R., & Atallah, E. H. (2019). A New Perspective toward Cataloging Northern Hemisphere Rossby Wave Breaking on the Dynamic Tropopause. Monthley Weather Review, 147(2). doi:10.1175/mwr-d-18-0131.1
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  Abstract Rossby wave breaking (RWB) events are a common feature on the dynamic tropopause and act to modulate synoptic-scale jet dynamics. These events are characterized on the dynamic tropopause by an irreversible overturning of isentropes and are coupled to troposphere-deep vertical motions and geopotential height anomalies. Prior climatologies have focused on the poleward streamer, the equatorward streamer, or the reversal in potential temperature gradient between the streamers, resulting in differences in the frequencies of RWB. Here, a new approach toward cataloging these events that captures both streamers is applied to the National Centers for Environmental Prediction Reanalysis-2 dataset for 1979–2011. Anticyclonic RWB (AWB) events are found to be nearly twice as frequent as cyclonic RWB (CWB) events. Seasonal decompositions of the annual mean find AWB to be most common in summer (40% occurrence), which is likely due to the Asian monsoon, while CWB is most frequent in winter (22.5%) and is likely due to the equatorward shift in mean baroclinicity. Trends in RWB from 1980 to 2010 illustrate a westward shift in North Pacific AWB during winter and summer (up to 0.4% yr−1), while CWB in the North Pacific increases in winter and spring (up to 0.2% yr−1). These changes are hypothesized to be associated with localized changes in the two-way interaction between the jet and RWB. The interannual variability of AWB and CWB is also explored, and a notable modality to the frequency of RWB is found that may be attributable to known low-frequency modes of variability including the Arctic Oscillation, the North Atlantic Oscillation, and the Pacific–North American pattern.
• Bowley, K. A., Gyakum, J. R., & Atallah, E. H. (2019). A new perspective toward cataloging northern Hemisphere Rossby wave breaking on the dynamic tropopause. Monthly Weather Review, 147(2), 409-431.
• Bowley, K. A., Gyakum, J. R., & Atallah, E. H. (2019). The role of dynamic tropopause Rossby wave breaking for synoptic-scale buildups in northern Hemisphere zonal available potential energy. Monthly Weather Review, 147(2), 433-455.
• Mccray, C. D., Atallah, E. H., & Gyakum, J. R. (2019). Long-duration freezing rain events over North America: Regional climatology and thermodynamic evolution. Weather and Forecasting, 34(3), 665-681.
• Milrad, S. M., Atallah, E. H., Gyakum, J. R., & Klepatzki, J. (2019). The extreme precipitation index (EPI): A coupled dynamic???thermodynamic metric to diagnose midlatitude floods associated with flow reversal. Weather and Forecasting, 34(5), 1257-1276.
• Bowley, K. A., Atallah, E. H., & Gyakum, J. R. (2018). Synoptic-scale zonal available potential energy increases in the Northern Hemisphere. Journal of the Atmospheric Sciences, 75(7), 2385-2403.
• Milrad, S. M., Lombardo, K., Atallah, E. H., & Gyakum, J. R. (2017). Numerical simulations of the 2013 Alberta flood: Dynamics, thermodynamics, and the role of orography. Monthly Weather Review, 145(8), 3049-3072.
• Gervais, M., Atallah, E., Gyakum, J. R., & Bruno Tremblay, L. (2016). Arctic air masses in a warming world. Journal of Climate, 29(7), 2359-2373.
• Milrad, S. M., Gyakum, J. R., & Atallah, E. H. (2015). A meteorological analysis of the 2013 Alberta flood: Antecedent large-scale flow pattern and synoptic-dynamic characteristics. Monthly Weather Review, 143(7), 2817-2841.
• Milrad, S. M., Gyakum, J. R., Lombardo, K., & Atallah, E. H. (2015). Corrigendum to A generalization of Petterssen's frontogenesis function and its relation to the forcing of vertical motion [Mon. Wea. Rev., 116, (1988), 762-780] DOI:10.1175/1520-0493(1988)116<0762:AGOPFF>2.0.CO;2.. Weather and Forecasting, 30(5), 1404.
• Plante, M., Son, S., Atallah, E., Gyakum, J., & Grise, K. (2015). Extratropical cyclone climatology across eastern Canada. International Journal of Climatology, 35(10), 2759-2776.
• Gervais, M., Gyakum, J. R., Atallah, E., Tremblay, L. B., & Neale, R. B. (2014). How well are the distribution and extreme values of daily precipitation over North America represented in the community climate system model? A comparison to reanalysis, satellite, and gridded station data. Journal of Climate, 27(14), 5219-5239.
• Gervais, M., Tremblay, L. B., Gyakum, J. R., & Atallah, E. (2014). Representing extremes in a daily gridded precipitation analysis over the United States: Impacts of station density, resolution, and gridding methods. Journal of Climate, 27(14), 5201-5218.
• Milrad, S. M., Atallah, E. H., Gyakum, J. H., & Dookhie, G. (2014). Synoptic typing and precursors of heavy warm-season precipitation events at Montreal, Qu??bec. Weather and Forecasting, 29(2), 419-444.
• Milrad, S. M., Gyakum, J. R., Lombardo, K., & Atallah, E. H. (2014). On the dynamics, thermodynamics, and forecast model evaluation of two snow-burst events in Southern Alberta. Weather and Forecasting, 29(3), 725-749.
• Small, D., Atallah, E., & Gyakum, J. R. (2014). An objectively determined blocking index and its Northern Hemisphere climatology. Journal of Climate, 27(8), 2948-2970.
• Hryciw, L. M., Atallah, E. H., Milrad, S. M., & Gyakum, J. R. (2013). A meteorological analysis of important contributors to the 1999-2005 canadian prairie drought. Monthly Weather Review, 141(10), 3593-3609.
• Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2013). Precipitation modulation by the saint lawrence river valley in association with transitioning tropical cyclones. Weather and Forecasting, 28(2), 331-352.
• Small, D., Gyakum, J. R., & Atallah, E. H. (2013). An Objectively Determined Blocking Index and its Northern Hemisphere Climatology. Journal of Climate, 27(8), 2948-2970. doi:10.1175/jcli-d-13-00374.1
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  AbstractA modified blocking index is defined based on vertically integrated potential vorticity. The application of this index identifies blocking activity over the Northern Hemisphere during all seasons. The index is developed by systematically identifying the magnitude and spatial scale that best characterizes persistent anticyclonic circulation anomalies in different seasons. By applying a systematic approach to the detection of blocking, the interannual, seasonal, and intraseasonal patterns of blocking frequency across the Northern Hemisphere are able to be characterized. The results are consistent with previous studies in finding that blocking is more frequent in the cold season months than in the warm season, although the results suggest that blocking occurs much more frequently in the summer and fall than many studies have previously reported. By examining blocking frequency monthly, interesting patterns of intraseasonal variability are found, especially over the central Pacific in August and the e...
• Razy, A., Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2012). Synoptic-scale environments conducive to orographic impacts on cold-season surface wind regimes at Montreal, Quebec. Journal of Applied Meteorology and Climatology, 51(3), 598-616.
• Ressler, G. M., Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2012). Synoptic-scale analysis of freezing rain events in Montreal, Quebec, Canada. Weather and Forecasting, 27(2), 362-378.
• Hanesiak, J. M., Stewart, R. E., Bonsal, B. R., Harder, P., Lawford, R., Aider, R., Amiro, B. D., Atallah, E., Barr, A. G., Black, T. A., Bullock, P., Brimelow, J. C., Brown, R., Carmichael, H., Derksen, C., Flanagan, L. B., Gachon, P., Greene, H., Gyakum, J., , Henson, W., et al. (2011). Characterization and summary of the 1999-2005 Canadian prairie drought. Atmosphere - Ocean, 49(4), 421-452.
• Milrad, S. M., Gyakum, J. R., Atallah, E. H., & Smith, J. F. (2011). A diagnostic examination of the eastern Ontario and western Quebec wintertime convection event of 28 January 2010. Weather and Forecasting, 26(3), 301-318.
• Small, D., Atallah, E., & Gyakum, J. (2011). Wind regimes along the Beaufort Sea coast favorable for strong wind events at Tuktoyaktuk. Journal of Applied Meteorology and Climatology, 50(6), 1291-1306.
• Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2010). A diagnostic examination of consecutive extreme cool-season precipitation events at St. John's, Newfoundland, in December 2008. Weather and Forecasting, 25(4), 997-1026.
• Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2010). Synoptic typing of extreme cool-season precipitation events at St. John's, Newfoundland, 1979-2005. Weather and Forecasting, 25(2), 562-586.
• Durnford, D., Gyakum, J., & Atallah, E. (2009). The conversion of total column ozone data to numerical weather prediction model initializing fields, with simulations of the 24-25 January 2000 East Coast snowstorm. Monthly Weather Review, 137(1), 161-188.
• Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2009). Dynamical and precipitation structures of poleward-moving tropical cyclones in eastern Canada, 1979-2005. Monthly Weather Review, 137(3), 836-851.
• Milrad, S. M., Atallah, E. H., & Gyakum, J. R. (2009). Synoptic-scale characteristics and precursors of cool-season precipitation events at St. John's Newfoundland, 1979-2005. Weather and Forecasting, 24(3), 667-689.
• Roberge, A., Gyakum, J. R., & Atallah, E. H. (2009). Analysis of intense poleward water vapor transports into high latitudes of western North America. Weather and Forecasting, 24(6), 1732-1747.
• Atallah, E., Bosart, L. F., & Aiyyer, A. R. (2007). Precipitation distribution associated with landfalling tropical cyclones over the eastern United States. Monthly Weather Review, 135(6), 2185-2206.
• McTaggart-Cowan, R. .., Bosart, L. F., Gyakum, J. R., & Atallah, E. H. (2007). Hurricane Katrina (2005). Part I: Complex life cycle of an intense tropical cyclone. Monthly Weather Review, 135(12), 3905-3926.
• McTaggart-Cowan, R. .., Atallah, E. H., Gyakum, J. R., & Bosart, L. F. (2006). Hurricane Juan (2003). Part I: A diagnostic and compositing life cycle study. Monthly Weather Review, 134(7), 1725-1747.
• McTaggart-Cowan, R. .., Bosart, L. F., Davis, C. A., Atallah, E. H., Gyakum, J. R., & Emanuel, K. A. (2006). Analysis of Hurricane Catarina (2004). Monthly Weather Review, 134(11), 3029-3053.
• McTaggart-Cowan, R. .., Bosart, L. F., Gyakum, J. R., & Atallah, E. H. (2006). Hurricane Juan (2003). Part II: Forecasting and numerical simulation. Monthly Weather Review, 134(7), 1748-1771.
• Atallah, E. H., & Bosart, L. F. (2004). An evaluation of the precipitation distribution in landfalling tropical cyclones. Bulletin of the American Meteorological Society, 2601-2602.
• Galarneau Jr., ,., Bosart, L. F., Aiyyer, A. R., & Atallah, E. H. (2004). Global climatology of 1000-500 HPA thickness highs and lows. Bulletin of the American Meteorological Society, 2195-2199.
• Atallah, E. H., & Bosart, L. F. (2003). The extratropical transition and precipitation distribution of hurricane Floyd (1999). Monthly Weather Review, 131(6), 1063-1081.
• Bals-Elsholz, T. M., Atallah, E. H., Bosart, L. F., Wasula, T. A., Cempa, M. J., & Lupo, A. R. (2001). The wintertime southern hemisphere split jet: Structure, variability, and evolution. Journal of Climate, 14(21), 4191-4215.

Proceedings Publications

• Atallah, E. H. (2018, January). A Simple Definition of Flow Regimes and Its Relationship to High-Impact Weather Events. In 31st Conference on Climate Variability and Change.
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  Historically, maxima in the variance of the mass field have been one of the metrics used to identify storm tracks. Consequently a simple definition of a flow regime is developed here using the variance of the 500 hPa height field over different time scales (7, 15, and 30 days) in order to identify active versus quiescent periods in the entrance and exit regions of the climatological storm tracks. Furthermore a metric is developed to assess flow stagnation which here is defined as a 24 h period of sustained geostrophic easterlies at 500 hPa calculated over 10 degrees longitude bands. This flow stagnation is then combined with a measure of air mass quality through an assessment of the layer-averaged equivalent potential temperature anomalies in order to highlight regions that are susceptible to high impact precipitation events. Preliminary results suggest that low variance (decreased storm track activity) regimes in the eastern North Pacific are associated with a combination of an equatorially displaced and westward retracted jet in the North Pacific basin as well a preference for the positive phase of the Pacific North American pattern. Flow stagnation in this regime occurs preferentially in the Gulf of Alaska and extends southwestward along the West Coast of North America with a separate maximum situated in the southwestern United States in association with anticyclonic wave breaking. In the western North Atlantic, low variance regimes are associated with an equatorially displaced and weakened jet (consistent with the negative phase of the North Atlantic Oscillation) with abnormally warm conditions over central Canada. Flow stagnation in this regime occurs preferentially in Ontario and Quebec with a strong decrease in anticyclonic wave breaking suggested over the portions of the subtropical Atlantic.
• Atallah, E. H. (2017, Summer). An Investigation into the Impacts of Sea-Surface Temperature Anomalies on Oceanic Cyclogenesis in the winters of 2014 and 2015. In 28th Conference on Weather Analysis and Forecasting.
• Atallah, E. H. (2015, Summer). A Comparison of the Winters of 2013-2014 and 2014-2015. In Weather Analysis and Forecasting.