Montgomery Research Group

Satellite Observation in the Marsupial Framework (NOGAPS) PG21L

	20090903	20090904	20090905	20090906	Loop
QuikSCAT	Earth-relative vs. Comoving	Earth-relative vs. Comoving	Earth-relative vs. Comoving	Earth-relative vs. Comoving
CIMSS-TPW	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z
GOES-IR	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z

Satellite Observation in the Marsupial Framework (UKMET) PG21L

	20090903	20090904	20090905	20090906	Loop
QuikSCAT	Earth-relative vs. Comoving	Earth-relative vs. Comoving	Earth-relative vs. Comoving	Earth-relative vs. Comoving
CIMSS-TPW	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z
GOES-IR	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z	00Z vs. 00Z

Forecast of PG21L based on GFS operational data

Initialization Time

Hovmoller Diagram

Day 1

Day 2

Day 3

Day 4

Loop

Pouch Track

000

012

024

036

048

060

072

084

096

2009090200

Hovmoller of RH and V

Zeta, OW, RH, Shear

Zeta, OW, RH, Shear500 Shear250

Track Text

2009090100

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009083100

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082800

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082700

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

Forecast of PG21L based on NOGAPS operational data

Initialization Time

Hovmoller Diagram

Day 1

Day 2

Day 3

Day 4

Loop

Pouch Track

000

012

024

036

048

060

072

084

096

2009090600

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009083100

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082800

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082700

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082600

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082512

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

Forecast of PG21L based on UKMET operational data

Initialization Time

Hovmoller Diagram

Day 1

Day 2

Day 3

Day 4

Loop

Pouch Track

000

012

024

036

048

060

072

084

096

2009090600

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009090500

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009083100

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082800

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082700

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082600

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

2009082512

Hovmoller of RH and V

Zeta, OW, RH, Shear

Track Text

Back to 2009 archive

The following is a description of the quantities plotted:

ZETA: Relative vertical vorticity. Unit: 10^-5 s^-1.
OW: Okubo-Weiss parameter, defined as relative vorticity squared minus strain rate squared:
OW = zeta² - S1² - S2² = (Vx-Uy)² - (Ux-Vy)² - (Vx+Uy)²

Positive OW highlights the region where curvature vorticity dominates shear vorticity. Note that both cyclonic and anticyclonic vorticity contribute to positive OW, but in the products, only the area with cyclonic vorticity is highlighted. Unit: 10^-9 s^-2.
TPW: Total precipitable water in the column from GFS. Unit: kg/m².
Shear: Vector wind difference between 500hP and 850hPa. (In some previous storms/invests the deep shear between 850 hPa and 200 hPa was calculated, as indicated in the bottom of the figures). Unit: m/s
SF: Atmospheric column relative humidity from GFS, which is equivalent to Dave Raymond’s "Saturation Fraction" (the ratio of total precipitable water in the column to the total saturated precipitable water in the column). It usually has the same pattern/variations as TPW. Unit: %(percent).
Cp: Phase speed of the wave pouch (the translation speed). For simplicity, we assume that the wave propagates zonally at a constant phase speed. The phase speed is updated for each model run. Unit: m/s. [A generalization of this quanitity will be presented soon for oblique wave propagation.]
X: Vertical cross sections of meteorological variables within the pouch. Click here [PDF] for a detailed description of this product.

The streamlines in each figure are shown in a frame of reference which moves at the same (zonal) speed as the wave pouch, and the (zonal) translation speed is indicated at the top right label in each figure. The purple curve represents the local critical surface, where the zonal flow equals the phase speed of the wave pouch. The black curve is the wave trough axis, where the meridional flow is zero and the relative vorticity is cyclonic. The black circle indicates the center of the pouch.

The 5-day track of the pouch is shown in the top panel of the figure in the last column of the table.

If an invest eventually develops into a named storm, the location of the genesis (from NOAA's National Hurricane Center) is marked on the map as a red circle, and the location of the pouch at the actually genesis time is highlighted in red. The other four panels in the figure show the time evolution of several variables averaged in a 3-degree by 3-degree box following the pouch. Missing values (-999) indicate an open wave (the flow is open in the moving frame of reference).

Department of Meteorology

Satellite Observation in the Marsupial Framework (NOGAPS) PG21L

Satellite Observation in the Marsupial Framework (UKMET) PG21L

Forecast of PG21L based on GFS operational data

Forecast of PG21L based on NOGAPS operational data

Forecast of PG21L based on UKMET operational data

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