Transcript Precipitation Shadows in the Hudson Valley

Precipitation Shadows
in the Hudson Valley
Hudson Valley Ambient Meteorology Study
(HVAMS)
National Science Foundation, Physical Meteorology Section
David R. Fitzjarrald, Atmospheric Sciences Research Center, UAlbany,
SUNY
Jeffrey M. Freedman, Atmospheric Information Services
and
1
Ricardo K. Sakai , Matt Czikowsky1, Alex Tsoyref1, and Jessica Neiles2
1. ASRC
2. NWS, Wilmington, NC
Thomas Cole: River in the Catskills (1830s)
The Hudson Valley
Northeast Escarpment
Catskills
ALB
NYC
HPN
Source: http://visibleearth.nasa.gov/U_S__States/New_York/32_6.html
Hudson Valley Ambient
Meteorology Study
Opportunistic events: heavy
rains and rain shadows during
IFC
P: ISFF
H:
HOBOs
KENX
KEY: Dense
network of
stations
20 km
South Albany (P8) through Freehold (H2), East
Jewett (H2) to Phoenicia
East Jewett (H3)
So. Albany
P8
Freehold
(H2)
Catskills
Phoenicia
History
Three Cases
• 23 September 2003
• 26 - 27 October 2003
• 29 October 2003
Briefly examine the first two…
23 September 2003
Short event (most
precipitation in 2 4 hr period)
Heaviest rainfall
over southern
Catskills (70+
mm)
Distinct
precipitation
shadow to northnortheast (< 20
mm)
1200 UT 23 September 2003
1200 UT 23 September 2003
1200 UT 23 September 2003
KENX Storm Total
Precipitation
Escarpment
26 - 27 October 2003
Steady rain for
24+ hours
Heaviest rainfall
over central
Catskills (90+
mm)
Again, distinct
precipitation
shadow to northnortheast (< 30
mm)
1200 UT 27 October 2003
Mountain Waves?
• Comparatively modest terrain, but…
• Brady and Waldstreicher (2001)
• Poconos of NE PA
• Conditions favoring mountain waves:
• Decreasing static stability with height
• Stable layer near mountain top level
• Decrease of cross barrier flow with
height.
KENX VAD Profile
1052 - 1146 UT 23 Sep 2003
KENX VAD Profile
1227 - 1320 UT 27 Oct 2003
Eta Model Sounding
0600 UT 23 September 2003
From ASRC Air Quality Forecasting Modeling System
Conclusions(?)
• Distinct precipitation shadows downwind
of Catskill Escarpment
• Hint of mountain waves (ducted gravity
waves?)
• Need further study: incorporate data
from other networks (NYCDEP); stability
parameters from model soundings
Acknowledgments
•University at Albany participation:
ASRC: Scientists David Fitzjarrald, Ricardo Sakai (Ph. D. ‘00)
Technician Alex Tsoyref
Graduate Student: Matt Czikowsky (M. Sc. ‘03)
Project Assistant: Jessica Neiles (B. Sc. ‘03)
Undergraduate students:
Jason Herb
Kim Sutkevich
Aaron Feinberg
•• Atmospheric Information Services:
Co-Investigator: Jeff Freedman, (Ph. D. ‘00)
Acknowledgments
• Brazilian collaborators from the U.
of Santa Maria, RS:
Osvaldo Moraes
(postdoctoral visitor ‘90)
Otávio Acevedo (Ph. D. ‘01)
Rodrigo da Silva (visiting
grad. Student ‘02,’03)
Acknowledgments
Facilities made available through the Deployment Pool funds of
The NSF:
• Wyoming King Air instrumented aircraft
• 9 ISSF automatic weather stations from the National
Center for Atmospheric Science (NCAR), Boulder CO
• TAOS tethered balloon sounder (NCAR)
Facility available through collaboration with the University of
Alabama, Huntsville: MIPS
• Collaboration with NOAA/NWS
Radar wind profiler at Schenectady airport
Additional balloon soundings at the National Weather Service
Forecast Office, Albany.