http:celebrating200years'noaa'goveventsstormwelcome'html - PowerPoint PPT Presentation

Title: http:celebrating200years'noaa'goveventsstormwelcome'html


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Past, Future, and Ongoing Field Experiments in
the Atmospheric Sciences for Western North
Carolina
Douglas Miller, UNCA
http//www.stowy.net/asheville/avlflood.htm
http//celebrating200years.noaa.gov/events/storm/w
elcome.htmlfirsts
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Outline

• Forecast challenges
• Warm season precipitation
• Cold season precipitation
• Field experiments

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Forecast challenges
Western North Carolina
Courtesy Greg Dobson
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Forecast challenges

• Mountain meteorology
• Very localized effects
• Temperature
• Wind speeds
• Wind direction
• Moisture
• Precipitation

http//www.erh.noaa.gov/gsp/localdat/NWFS_discussi
on_group/nwfs_discussion_group.html
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Forecast challenges

• Precipitation
• Where?
• How much?
• In what form?
• Where will it go?

Courtesy NWS
http//www.erh.noaa.gov/gsp/localdat/cases/26June2
006Flooding/26June06Flooding.html
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Forecast challenges
Courtesy Greg Dobson
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Dying tropical systems
Courtesy NWS
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ATMS 373- Introduction
Dying tropical systems
Courtesy NWS
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Snowfall
Courtesy NWS
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Forecast challenges

• The red light, green light game
• In general, you cant forecast
• what you dont see
• what you dont understand
• In weather forecasting, both issues (seeing and
  understanding) involve observations

http//www.bbc.co.uk/blogs/ni/religion/
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Forecast challenges

• Warm Season precipitation amount
• Convection
• Organized linear convection
• Propagate into western NC
• Isolated thunderstorms
• Locally generated
• Dying tropical systems

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Forecast challenges

• Warm Season example
• Flash flooding along Twelvemile Creek and the
  Hickory Nut Gorge on 26 June 2006
• National Weather Service Greenville
  Spartanburg, SC

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Forecast challenges

• Warm Season example

1200 UTC 26 Jun 2006
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Forecast challenges

• Warm Season example

1145 UTC 26 Jun 2006
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Forecast challenges

• Warm Season example

1111 UTC 26 Jun 2006
WESTERN NORTH CAROLINA BAT CAVE 4 N 9.63
THOMASVILLE 9.25 SALUDA 1.5 SW 9.17 ASHE 8.25
HENDERSONVILLE 2 N 7.75 BUSICK 5.43 CULLOWHEE
4.49 BREVARD 4.48 MOUNT MITCHELL 3.63
ASHEVILLE AIRPORT 2.79
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Forecast challenges

• Warm Season example

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Forecast challenges

• Warm Season example

Rocky Broad River at Bat Cave, NC
major flooding
flood stage
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Forecast challenges

• All our operational gauges in mountainous areas
  tend to be located in easy access locations
• Roads follow rivers
• Rivers are in valleys (low elevations)
• Note

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Forecast challenges
http//www.nc-climate.ncsu.edu/cronos/map/index.ph
p
data (observations) void lack of observations
in the mountains, particularly at high elevations
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Forecast challenges
our radar and satellite precipitation estimation
algorithms are generally tuned using observations
located in low elevation regions
Does this cause a bias in our estimates?
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Forecast challenges

• Cold Season precipitation type
• Cold air damming

Courtesy COMET
http//www.meted.ucar.edu/mesoprim/cad/
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Forecast challenges

• Cold Season precipitation type

Courtesy COMET
http//www.meted.ucar.edu/mesoprim/cad/
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Forecast challenges

• Cold Season precipitation type

Courtesy COMET
http//www.meted.ucar.edu/mesoprim/cad/
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Forecast challenges

• Cold Season precipitation type
• Is a warm nose likely?
• If so,
• How deep is the warm air?
• How deep is the cold air next to the ground?

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Forecast challenges

• Cold Season precipitation amount
• Northwest flow snowfall (NWFS)
• http//www4.ncsu.edu/nwsfo/storage/training/assor
  ted/lee_nwflow.ppt
• Getting snow when you shouldnt

Photo Dr. Baker Perry
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Forecast challenges

• Cold Season precipitation amount
• Snow ingredients
• Cold air
• Moisture
• Lift

http//blogs.trb.com/news/weather/weblog/wgnweathe
r/weather_snap_shots/full/
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Forecast challenges

• Cold Season precipitation amount
• Snow
• Cold air
• Moisture
• Lift

1500 UTC 9 Jan 2007
http//www.erh.noaa.gov/gsp/localdat/cases/9-10Jan
2007NWFS/9-10Jan2007NWFS.html
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Forecast challenges

• Cold Season precipitation amount
• Snow
• Cold air
• Moisture
• Lift

0000 UTC 10 Jan 2007
http//www.erh.noaa.gov/gsp/localdat/cases/9-10Jan
2007NWFS/9-10Jan2007NWFS.html
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Forecast challenges

• Cold Season precipitation amount
• Snow
• Cold air
• Moisture
• Lift

1600 UTC 10 Jan 2007
http//www.erh.noaa.gov/gsp/localdat/cases/9-10Jan
2007NWFS/9-10Jan2007NWFS.html
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Field experiments
Courtesy Greg Dobson
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Field experiments

• Warm Season Pigeon River Basin
• Initiated June 2007
• Ongoing for four years
• PI Dr. Ana Barros, Duke University
• NASA

Precipitation amount
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Field experiments
Courtesy Greg Dobson
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Field experiments

• Warm Season Pigeon River Basin
• Preliminary results

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6
4
3800 ft
2
0.8 mi
5
4.5 mi
1
5300 ft
3
4.25 mi
6300 ft
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Field experiments

• Preliminary results
• 14 September 2007

FXUS62 KGSP 140539 AFDGSP AREA FORECAST
DISCUSSION NATIONAL WEATHER SERVICE
GREENVILLE-SPARTANBURG SC 139 AM EDT FRI SEP 14
2007 .SYNOPSIS... THE REMNANTS OF HUMBERTO WILL
MOVE NORTHEASTWARD AND AFFECT THE FORECAST AREA
TODAY. A COLD FRONT WILL CROSS THE AREA FROM THE
NORTHWEST ON SATURDAY...WITH COOL AND DRY HIGH
PRESSURE SETTLING IN BEHIND IT THROUGH THE EARLY
PART OF NEXT WEEK .
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Field experiments

• Preliminary results
• 14 September 2007
• Three precipitation main events
• Record rainfall at AVL

000 SXUS72 KGSP 150649 RERAVL RECORD EVENT
REPORT NATIONAL WEATHER SERVICE
GREENVILLE-SPARTANBURG SC 241 AM EDT SAT SEP 15
2007 ...RECORD DAILY MAXIMUM RAINFALL SET AT
ASHEVILLE... AT THE ASHEVILLE REGIONAL
AIRPORT...ON FRIDAY 3.4 INCHES OF RAIN FELL. THIS
BREAKS THE OLD RECORD OF 2.03 INCHES SET IN
1978. MOORE
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800 am 14 Sep 2007
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-27.1oC 0.51
-36.1oC 0.23
800 am 14 Sep 2007
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Field experiments
800 am
200 am
200 pm
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Field experiments

• 14 Sep 2007 event observations
• For a disorganized convective system
• High elevation rain gauges indicate that higher
  elevation doesnt necessarily mean more
  accumulated precipitation
• What about for a larger scale organized system?

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Field experiments

• Cold Season Asheville area (WWC)
• Initiated Nov 2006
• Ended April 2007
• PI Dr. Douglas Miller, UNC Asheville
• COMET

Precipitation type
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Field experiments
Courtesy Greg Dobson
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Field experiments

• Cold Season Asheville area (WWC)
• Preliminary results

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0300 UTC 1 Feb 2007 sea level pressure
H
L
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WWC
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SEMPE Radiosonde Launch 1 1100 UTC Skew-T
created using MATLAB
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Inversion base
Isothermal layer
1100 SEMPE Radiosonde Launch Winds
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AVL meteogram
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P-type observations for AVL and the surrounding
area Warren Wilson College (WWC), Greenville, SC
(GMU), Charlotte, NC (CLT), and Franklin, NC
(1A5) indicate more sporadic precipitation than
had been anticipated at AVL in contrast to the
continuous precipitation observed at surrounding
stations. S snow, Z freezing rain, R
rain, and NO no observation taken. Times in
UTC.
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WV
VA
KY
NC
TN
SC
AL
GA
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1.5 km grid spacing topography (decameters)
WWC
AVL
Franklin
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850 hPa Air Parcel Trajectory
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700 hPa Air Parcel Trajectory
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RUC analysis (valid 1000 UTC 1 Feb 2007)
900 hPa dewpoint depression
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1100 UTC SEMPE
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Some theories, Asheville region

• Low-level cold air damming was in place initially
• Weak low-level winds and inversion aloft
  prevented cold dry air from mixing out overhead
  of the AVL region
• Southerly winds at AVL
• Easterly winds at WWC
• Mid-level air traveled over the mountains and
  deposited its moisture in southwestern North
  Carolina before arriving over the AVL region

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Field experiments

• Cold Season Boone area (Poga Mntn)
• Initiated Dec 2007
• Ongoing through cold season (April 2008)
• PI Dr. Baker Perry, App. State University
• Co-PI Dr. Sandra Yuter, NC State University
• UNC-GA

Precipitation amount
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Field experiments
Courtesy Greg Dobson
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Field experiments

• Cold Season Boone area (Poga Mntn)
• Preliminary results
• Site photo here

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Field experiments

• Cold Season precipitation amount

1200 UTC 2 Jan 2008
http//www.hpc.ncep.noaa.gov/html/sfc_archive.shtm
l
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Field experiments

• Cold Season precipitation amount

1200 UTC 2 Jan 2008
http//www.hpc.ncep.noaa.gov/dailywxmap/index_2008
0101.html
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Field experiments
Blue NARR Green NAM Red GFS
0300 UTC 2 Jan 2008
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Field experiments
sublimational cooling
Blue NARR Green NAM Red GFS
0600 UTC 2 Jan 2008
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Field experiments

• Cold Season precipitation amount

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1200 UTC 3 Jan 2008
ratio 1 to 8 (wet snow)
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Field experiments

• Cold Season precipitation amount

1200 UTC 3 Jan 2008
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Field experiments

• Cold Season precipitation amount

1200 UTC 3 Jan 2008
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Field experiments
GFS

• Cold Season precipitation amount

GFS or NAM as initial conditions
NAM
1200 UTC 3 Jan 2008
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Snow streak
Knoxville
Mt. Mitchell
Asheville
Jan. 3, 2008 1145 EST
Courtesy Grant Goodge
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Mt. Mitchell
Asheville
Jan. 2, 2008 1330 EST
Courtesy Grant Goodge
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Field experiments

• Cold Season Boone area (Poga Mntn)
• Preliminary results- Jan 1-3, 2008 NWFS event
• Moist, unstable layer of air next to the ground
  is too shallow in the computer model simulations
• Model misses sublimation process 700 hPa level
• Computer model puts too much snow along the peaks
  of the mountains in western NC and VA
• Computer model puts too little snow downwind of
  the Appalachian Mountains
• Total simulated precipitation volume may be
  nearly correct

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Future field experiments HMT Southeast (April
2010)
http//hmt.noaa.gov/
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Hydrometeorology Testbed Program (HMT)
The national Hydrometeorological Testbed program
will be implemented incrementally in different
regions of the U.S.
Mean annual precipitation (inches)
HMT WEST - Cool Season
American River Basin (Sierra Nevada)
HMT SOUTHEAST All Season, including
Hurricane Landfall
HMT CENTRAL Warm Season
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HMT Observing Systems