Jennifer Q. Belge Eric G. Hoffman Plymouth State University 11/06/08 Northeast Regional Operational Workshop Preferred Regions of Convective Development over Northern New England as a Function of Flow Regime: Southwesterly Flow Case Studies

Previous Work- Evan Lowery (2008)  5 year climatology of northern New England thunderstorms KGYX radar domain April – September SCIT  Spatial distribution of cells as a function of large- scale flow at 700 hPa

Results- Lowery (2008)  SW FLOW 5 clusters ○ Central Oxford, Franklin and Somerset counties in ME ○ Just south of Belknap, Merrimack border in NH ○ Southern Oxford county in ME ○ Northern Grafton county in NH ○ Southern Somerset county in ME Grafton Oxford Franklin Somerset Coos Carroll Belknap Merrimack York Strafford Rockingham Hillsborough Sullivan Cheshire Piscataquis Aroostook Cumberland Androscoggin Kennebec Penobscot Waldo Knox Lincoln Sagadahoc  NW FLOW  3 clusters  Border of Strafford (NH) and York (ME) counties  Tri-county border of Oxford (ME), Carroll (NH) and York(ME)  Border of Grafton (NH) and Coos (NH) county

Motivation  Lowery’s study did not address: Why are there preferred regions of development with respect to flow regime? Differences between flow regimes?  Forecasting potential KGYX

Scientific Questions  Why do thunderstorm cells initiate where they do as a function of large-scale flow? SW and 700 hPa only  Are there certain meteorological patterns present in the mesoscale environment that is conducive to convection in these regions found by Lowery (2008)?

Data and Methodology  Case Studies Radar reflectivity examined for each case from May- September 2007 only  Case study selection 1. Cells were to initiate in the significant areas identified by Lowery (2008) 2. Cells were to not be associated with a frontal zone ○ Eliminate influence of frontal boundary in mesoscale analysis

NW FLOW

SW FLOW

Results  Radar  Sounding 12 UTC KGYX  Surface analysis  RUC Synoptic overview 12 UTC  LAPS KGYX Mesoscale analysis 17 UTC

July 13, 2007

Synoptic Analysis 12 UTC

Surface Analysis 12 UTC

500 hPa Height 12 UTC

250 hPa Height and Wind 12 UTC

Sounding 12 UTC

Mesoscale Analysis 17 UTC

Surface Analysis 18 UTC

Surface Dew Point 17 UTC

Surface CAPE 17 UTC

Surface Flow Vectors and Topo 17 UTC

Surface Convergence 17 UTC

Mean Sea Level Pressure 17 UTC

Conclusions

Preliminary Results  July 13, 2007 SW Flow Case Moisture & instability sufficient over entire area ○ Genesis region was not unique Surface convergence and corresponding surface trough  could provide the necessary lift  Results from the August 2, 2007 case show the same results and conclusions

WORKS CITED Lowery, E.M, 2008: Using the WSR-88D Storm Structure Product to Develop a Climatology of Northern New England Thunderstorms as a Function of Large-Scale Flow, Plymouth State University, Master of Science Thesis WORKS CITED Lowery, E.M, 2008: Using the WSR-88D Storm Structure Product to Develop a Climatology of Northern New England Thunderstorms as a Function of Large-Scale Flow, Plymouth State University, Master of Science Thesis Questions?