assessing the predictability of band formation and evolution during three recent northeast u.s....
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![Page 1: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/1.jpg)
Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms
David R. NovakNOAA/ NWS Eastern Region Headquarters, Scientific Services Division, Bohemia, New York
Stony Brook University, State University of New York, Stony Brook, New York
Brian A. ColleStony Brook University, State University of New York, Stony Brook, New York
© New York Times
![Page 2: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/2.jpg)
MotivationHigh-resolution models are capable of simulating mesoscale snowbands
![Page 3: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/3.jpg)
1800 UTC 25 Dec 2002 Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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1815 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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1830 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
![Page 6: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/6.jpg)
1845 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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1900 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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1915 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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1930 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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1945 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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2000 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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2015 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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2030 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
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2045 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
![Page 15: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/15.jpg)
2100 UTC
Dual Doppler 4 km MM5
•Radar Reflectivity (shaded, dBZ)
•3 km winds
![Page 16: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/16.jpg)
MotivationHigh-resolution models are capable of simulating mesoscale snowbands
An ensemble of high-resolution models may provide useful band predictability information
However, in the words of Rich Grumm: “high-resolution deterministic forecasts can be highly detailed, but highly inaccurate.”
![Page 17: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/17.jpg)
Objectives
Demonstrate ability of a high-resolution ensemble to provide qualitative band predictability information during three recent snowstorms
Explore sources of band uncertainty
25 Dec 2002
12 Feb 2006
14 Feb 2007
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Ensemble Design-multi-model (MM5 v3 /WRF-ARW v 2.2)
-multi-initial condition (GFS/NAM/SREF)
-multi-physics (Microphysics/Convective)
Member Model IC/BC Microphysics Convective PBLNAM-MM5 MM5 NAM Simple Grell MRFGFS-MM5 MM5 GFS Simple Grell MRFGFS-MM5-R2 MM5 GFS Reisner2 Grell MRFSREF_N1-MM5 MM5 SREF_N1 Simple Grell MRFSREF_N2-MM5 MM5 SREF_N2 Simple Grell MRFSREF_P1_MM5 MM5 SREF_P1 Simple Grell MRFSREF_P1- MM5-KF MM5 SREF_P1 Simple Kain Fritch MRFSREF_P2-MM5 MM5 SREF_P2 Simple Grell MRFNAM-WRF WRF NAM WSM-3 Grell MRFGFS-WRF WRF NAM WSM-3 Grell MRFGFS-WRF-Thom WRF GFS Thompson Grell MRFSREF_N1-WRF WRF SREF_N1 WSM-3 Grell MRFSREF_N2-WRF WRF SREF_N2 WSM-3 Grell MRFSREF_P1_WRF WRF SREF_P1 WSM-3 Grell MRFSREF_P1- WRF-KF WRF SREF_P1 WSM-3 Kain Fritch MRFSREF_P2-WRF WRF SREF_P2 WSM-3 Grell MRF
•Initialized 15-21 h prior to band formation
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Band DefinitionModel band = simulated reflectivity feature which has an aspect ratio (length/width) of 4:1 or greater, with an
intensity of at least 30 dBZ, maintained for at least 2 h.
No BandBand
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Feb 14 2007
![Page 21: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/21.jpg)
14 Feb 2007 Surface Cyclone Depth
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Observed Ensemble
Storm Total Precipitation
![Page 23: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/23.jpg)
Band Occurrence
•16 of 16 members (100%) had bands at some time during event
![Page 24: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/24.jpg)
Band Timing
Band formation among members ranged from 14 UTC to 00 UTC
Band dissipation among member ranged from 22 UTC to 3 UTC
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Band LocationFormation
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Band LocationMaturity
![Page 27: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/27.jpg)
Band LocationDissipation
![Page 28: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/28.jpg)
Feb 14 2007 Summary
Band Characteristic
Spread Confidence
Occurrence 16/16 members High
Timing ~ 8 h Moderate
Location ~100 km High
![Page 29: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/29.jpg)
Dec 25 2002
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25 Dec 2002 Surface Cyclone Depth
![Page 31: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/31.jpg)
Observed Ensemble
Storm Total Precipitation
![Page 32: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/32.jpg)
Band Occurrence
•15 of 16 members (94%) had bands at some time during event
![Page 33: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/33.jpg)
Band Timing
Band formation among members ranged from 17 to 23 UTC
Band dissipation among members ranged from 20 UTC to 2 UTC
![Page 34: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/34.jpg)
Band LocationFormation
![Page 35: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/35.jpg)
Band LocationMaturity
![Page 36: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/36.jpg)
Band LocationDissipation
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25 Dec 2002 Summary
Band Characteristic
Spread Confidence
Occurrence 15/16 members High
Timing ~6 h Moderate
Location ~250 km Moderate
![Page 38: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/38.jpg)
12 Feb 2006
![Page 39: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/39.jpg)
12 Feb 2006 Surface Cyclone Depth
![Page 40: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/40.jpg)
Observed Ensemble
Storm Total Precipitation
![Page 41: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/41.jpg)
Band Occurrence
•12 of 16 members (75%) had bands at some time during event
![Page 42: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/42.jpg)
Band Timing
Band formation among members ranged from 10 to 20 UTC
Band dissipation among members ranged from 13 UTC to 0 UTC
![Page 43: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/43.jpg)
Band LocationFormation
![Page 44: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/44.jpg)
Band LocationMaturity
![Page 45: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/45.jpg)
Band LocationDissipation
![Page 46: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/46.jpg)
Band LocationAfter Dissipation
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12 Feb 2006 SummaryBand Characteristic
Spread Confidence
Occurrence 12/16 members Moderate
Timing ~9 h Low
Location ~400 km Low
![Page 48: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/48.jpg)
•Band occurrence was favored in the ensemble for each case
•However the specific timing and location of the bands had considerable spread, especially in the 25 Dec 2002 and 12 Feb 2006 cases.
Why?
![Page 49: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/49.jpg)
Location Difference (GFS errored left, NAM errored right)
14 Feb 2007
![Page 50: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/50.jpg)
36 km
NAM
0000 UTC
GFS
NAM - GFSR
~475 – 250 mb PV
-1 0 1 2 3 4 PVU -1 0 1 2 3 4
-2 -1 0 1 PVU
![Page 51: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/51.jpg)
36 km
NAM
0600 UTC
GFS
NAM - GFSR
~475 – 250 mb PV
-1 0 1 2 3 4 PVU
-1 0 1 2 3 4
-2 -1 0 1 PVU
![Page 52: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/52.jpg)
36 km
NAM
1200 UTC
GFS
NAM - GFSR
~475 – 250 mb PV
-1 0 1 2 3 4 PVU
-1 0 1 2 3 4
-2 -1 0 1 2 PVU
![Page 53: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/53.jpg)
36 km
NAM
1800 UTC
GFS
NAM - GFSR
~475 – 250 mb PV
-1 0 1 2 3 4 PVU -1 0 1 2 3 4
-2 -1 0 1 2 PVU
![Page 54: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/54.jpg)
Location Difference (SREF_N1 errored left, GFSR errored right)
25 Dec 2002
![Page 55: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/55.jpg)
36 km
GFSR
0000 UTC
SREF_N1
SREF_N1 - GFSR
~475 – 250 mb PV
-1 0 1 2 3 PVU -1 0 1 2 3 4
-2 -1 0 1 PVU
![Page 56: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/56.jpg)
36 km
GFSR
0600 UTC
SREF_N1
SREF_N1 - GFSR
~475 – 250 mb PV
-1 0 1 2 3 PVU -1 0 1 2 3
-2 -1 0 1 PVU
![Page 57: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/57.jpg)
36 km
GFSR
1200 UTC
SREF_N1
SREF_N1 - GFSR
~475 – 250 mb PV
-1 0 1 2 3 PVU -1 0 1 2 3
-2 -1 0 1 PVU
![Page 58: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/58.jpg)
36 km
GFSR
1800 UTC
SREF_N1
SREF_N1 - GFSR
-1 0 1 2 3 PVU -1 0 1 2 3
-2 -1 0 1 2 PVU
![Page 59: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/59.jpg)
Location Difference (GFSR errored left, SREF-N1 errored far right)
12 Feb 2007
![Page 60: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/60.jpg)
36 km
SREF_N1
1200 UTC
GFS
~475 – 250 mb PV
SREF - GFSR
-1 0 1 2 3 4 PVU
-2 -1 0 1 2 PVU
-1 0 1 2 3 4
![Page 61: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/61.jpg)
36 km
SREF_N1
1800 UTC
GFS
~475 – 250 mb PV
SREF - GFSR
-1 0 1 2 3 4 PVU
-2 -1 0 1 2 PVU
-1 0 1 2 3 4
![Page 62: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/62.jpg)
36 km
SREF_N1
0000 UTC
GFS
~475 – 250 mb PV
SREF - GFSR
-1 0 1 2 3 4 PVU
-2 -1 0 1 2 3 PVU
-1 0 1 2 3 4
![Page 63: Assessing the Predictability of Band Formation and Evolution during Three Recent Northeast U.S. Snowstorms David R. Novak NOAA/ NWS Eastern Region Headquarters,](https://reader035.vdocuments.mx/reader035/viewer/2022062407/56649d4e5503460f94a2d534/html5/thumbnails/63.jpg)
36 km
SREF_N1
0600 UTC
GFS
~475 – 250 mb PV
SREF - GFSR
-1 0 1 2 3 4 PVU
-2 -1 0 1 2 3PVU
-1 0 1 2 3 4
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36 km1200 UTC
GFS
~475 – 250 mb PV
SREF_N1
-1 0 1 2 3 4 PVU
-2 -1 0 1 2 PVU
-1 0 1 2 3 4
SREF - GFSR
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Summary•A simple 16-member 12-km multi-model,-initial condition, and -physics ensemble can identify favored time periods and corridors of band formation threat.
•Although band occurrence was favored in the ensemble for each case, the specific timing and location of the bands had considerable spread.
-suggests that answering whether a band will occur may be easier to answer than when or where it will occur, even at 12-24 h forecast projections.
•Spread of variables differed markedly amongst the three cases – appeared to be related primarily to IC uncertainty.
-suggests the largest improvements in band prediction may occur with targeted initial condition improvements.
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Model Comparison
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Model Comparison
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Model Comparison
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Spread
•Where is the spread coming from?
-Examine 24 h forecast MSLP spread (max MSLP minus min MSLP) for each sub ensemble
25 Dec 12 Feb 14 Feb Mean
IC 10.0 mb 8.5 mb 11.0 9.8 mb
Model 6.4 mb 2.1 mb 3.6 mb 4.0 mb
Physics 1.5 mb 0.3 mb 3.8 mb 1.8 mb
IC uncertainty dominates
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MSLP Spread Method
Member Model IC/BC Microphysics Convective PBLNAM-MM5 MM5 NAM Simple Grell MRFGFS-MM5 MM5 GFS Simple Grell MRFGFS-MM5-R2 MM5 GFS Reisner2 Grell MRFSREF_N1-MM5 MM5 SREF_N1 Simple Grell MRFSREF_N2-MM5 MM5 SREF_N2 Simple Grell MRFSREF_P1_MM5 MM5 SREF_P1 Simple Grell MRFSREF_P1- MM5-KF MM5 SREF_P1 Simple Kain Fritch MRFSREF_P2-MM5 MM5 SREF_P2 Simple Grell MRFNAM-WRF WRF NAM WSM-3 Grell MRFGFS-WRF WRF NAM WSM-3 Grell MRFGFS-WRF-Thom WRF GFS Thompson Grell MRFSREF_N1-WRF WRF SREF_N1 WSM-3 Grell MRFSREF_N2-WRF WRF SREF_N2 WSM-3 Grell MRFSREF_P1_WRF WRF SREF_P1 WSM-3 Grell MRFSREF_P1- WRF-KF WRF SREF_P1 WSM-3 Kain Fritch MRFSREF_P2-WRF WRF SREF_P2 WSM-3 Grell MRF
IC Spread= (MSLP spread of MM5 members with simple ice and Grell physics) + (MSLP spread of WRF members with simple ice and Grell physics) / 2
Members involved in calculation are highlighted
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MSLP Spread Method
Member Model IC/BC Microphysics Convective PBLNAM-MM5 MM5 NAM Simple Grell MRFGFS-MM5 MM5 GFS Simple Grell MRFGFS-MM5-R2 MM5 GFS Reisner2 Grell MRFSREF_N1-MM5 MM5 SREF_N1 Simple Grell MRFSREF_N2-MM5 MM5 SREF_N2 Simple Grell MRFSREF_P1_MM5 MM5 SREF_P1 Simple Grell MRFSREF_P1- MM5-KF MM5 SREF_P1 Simple Kain Fritch MRFSREF_P2-MM5 MM5 SREF_P2 Simple Grell MRFNAM-WRF WRF NAM WSM-3 Grell MRFGFS-WRF WRF NAM WSM-3 Grell MRFGFS-WRF-Thom WRF GFS Thompson Grell MRFSREF_N1-WRF WRF SREF_N1 WSM-3 Grell MRFSREF_N2-WRF WRF SREF_N2 WSM-3 Grell MRFSREF_P1_WRF WRF SREF_P1 WSM-3 Grell MRFSREF_P1- WRF-KF WRF SREF_P1 WSM-3 Kain Fritch MRFSREF_P2-WRF WRF SREF_P2 WSM-3 Grell MRF
Model Spread= [(NAM-MM5 minus NAM-WRF)+(GFS-MM5 minus GFS-WRF) + (GFS-MM5-R2 minus GFS-WRF-R2) + (SREF_N1-MM5 minus SREF_N1-WRF)+etc..] / 8
Members involved in calculation are highlighted
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MSLP Spread Method
Member Model IC/BC Microphysics Convective PBLNAM-MM5 MM5 NAM Simple Grell MRFGFS-MM5 MM5 GFS Simple Grell MRFGFS-MM5-R2 MM5 GFS Reisner2 Grell MRFSREF_N1-MM5 MM5 SREF_N1 Simple Grell MRFSREF_N2-MM5 MM5 SREF_N2 Simple Grell MRFSREF_P1_MM5 MM5 SREF_P1 Simple Grell MRFSREF_P1- MM5-KF MM5 SREF_P1 Simple Kain Fritch MRFSREF_P2-MM5 MM5 SREF_P2 Simple Grell MRFNAM-WRF WRF NAM WSM-3 Grell MRFGFS-WRF WRF NAM WSM-3 Grell MRFGFS-WRF-Thom WRF GFS Thompson Grell MRFSREF_N1-WRF WRF SREF_N1 WSM-3 Grell MRFSREF_N2-WRF WRF SREF_N2 WSM-3 Grell MRFSREF_P1_WRF WRF SREF_P1 WSM-3 Grell MRFSREF_P1- WRF-KF WRF SREF_P1 WSM-3 Kain Fritch MRFSREF_P2-WRF WRF SREF_P2 WSM-3 Grell MRF
Physics Spread= [(GFS-MM5 minus GFS-MM5-R2)+(GFS-WRF minus GFS-WRF-Thom)+(SREF_P1-MM5 minus SREF_P1-KF)+(SREF_P1-WRF minus SREF_P1-WRF-KF)] / 4
Members involved in calculation are highlighted