the northeast convective flash flood project: july 29 th 2009 flash flood case study

The Northeast Convective Flash Flood Project:

July 29th 2009 Flash Flood Case Study

Derek V. Mallia University at AlbanyDepartment of Atmospheric and Environmental SciencesSynoptic Meteorology Presentation

Outline:Synopsis of caseOverview of Synoptic/Mesoscale

FeaturesAnalysis of indicesConclusion

Data Sources Used:Advanced Weather Information Processing System

(AWIPS)Weather Event Simulator (WES)Rapid Update Cycle (RUC40) (RUC80)Albany Radar (KENX)Geostationary Operational Environmental Satellite

(GOES)

Synopsis of July 29 2009 Flash Flood Event• Widespread flash flood event• Occurred in:

Saratoga County Greene County Rensselaer County Columbia County Berkshire County

• One day event• Occurred between 17-01 UTC

• Frontal case• Associated with cold front

over Ontario Lake

Pictures from July 29th Event

Courtesy of Brian Frugis and Tim Scrom

Courtesy of Stefan Bagnato

WV Satellite and 500 hPa RUC 80 Height Loop

RUC 80 500hPa Height Analysis16 UTC

RUC 40 500hPa Height and Relative Vorticity

16 UTC 20 UTCUpstream Vorticity Maximums

Upstream Vorticity Maximums

RUC 40 250hPa Wind Analysis 16 UTC

RUC 40 250hPa Wind Analysis 20 UTC

RUC 40 250hPa Wind Analysis 00 UTC

RUC 40 250hPa Wind Divergence Analysis16 UTC

20 UTCRUC 40 250hPa Wind Divergence Analysis

RUC 40 PWAT & 850 hPa Wind and Theta-E Advection

16 UTC16 UTC

20 UTC

RUC 40 PWAT & 850 hPa Wind and Theta-E Advection

RUC 40 PWAT & 850 hPa Wind and Theta-E Advection

00 UTC

KENX Radar Image Loops 16:27-22:24 UTC

KENX Radar Image Loops 22:24-00 UTC

Surface Analysis 18 UTC

Surface Analysis 20 UTC

Sounding Derived Parameters

CAPE= 2614J/kg “tall and moderate CAPE”

K-Index= 32Total Totals= 47PWAT= 1.86 in.Freezing level= 13.9k ftDew point= lower 70s FMax low level wind= 30 kts; southwest

Conclusions:Dual vorticity and right entrance region of jet

provided favorable upper air dynamics

Baroclinic boundary provided focus for precipitation due to isentropic lift.

Plenty of moisture transport into region

High CAPE and moderate K-Index value suggest plenty of instability

Possible topographic effects?

AcknowledgementsJoe Villani; Albany National Weather Service Neil Stuart; Albany National Weather Service Julie Gabriel; University of DelawareAllen Srock; University at AlbanyNick Metz; University at AlbanyAnd the rest of the NWS staff!