radar palette home click doppler post cold frontal 1 poleward dcb the dcb tends to rise...

Post Cold Frontal 1Radar Palette Home Click Doppler

Poleward DCB

• The DCB tends to rise isentropically turning cyclonically• Typically in the dry slot of the comma pattern• Winds typically back with height above the cold frontal

surface• The cold frontal slope is steeper than the average 1:50• Cold front is likely Anabatic• Precipitation returns will be limited in extent• Precipitation will tend to be very cellular • This results in an incomplete display of the Doppler wind

field in particular

Click for the Conceptual Model and Explanation


DCB

Cold Frontal Cross-section along Poleward Branch of the Dry Conveyor Belt (DCB)

Cold air in Cold Conveyor Belt (CCB) deep and moist

Warm Conveyor Belt (WCB) is deep, warm and moist

CCB backs with height consistent with cold advection

Mixing Zone

SurfaceCold Front

Frontal slope is steeper than the typical 1:50

WCB oriented for

less frontal lift

Common area for deep instability

A

B

A B

WCB just ahead of cold front also typically veers with height

WCBCCB

Backing winds above the frontal zone indicative of anabatic cold front

Behind the Cold Front Conceptual ModelsLeft of the Col looking along the flow.

The same backing winds make the warm front anabatic and active as well.


DCB to the Left of the ColC

Cold frontal surface

Mixing layer

Dry CB

Within the DCB:•West of radar backing, cold advection, Anabatic cold front•East of radar nil VWS or possibly weaker backing

Within the CCB – Cold Advection:•Cold advection probably overpowers the Ekman spiral signature

The Cold Left Wing Climb CM

The eagles left wing is folded backward having just caught more air for a climb.This portion of the DCB in the dry slot is typically ascending.The right wing is still fully extended to catch the lift of the WCB.

oRight Wing

Left

Win

g

The steeper frontal slope of the cold front will be very evident. Notice that the frontal area outlined is an oval skewed to the cold side of the front.


The Cold Left Wing Climb CMThis cold front is oriented NE-SW.

Right Wing

Left

Win

g o

Click


Cross Section of Active Cold Front


Active or Anabatic Cold front


Under DCB

• This is the portion of the DCB pointing directly at the col in the associated deformation zone.

• It is almost a straight line flow separating cyclonic curvature to the left (poleward) from anticyclonic curvature to the right (equatorward)

• There is typically a dry delta pattern just upstream from the col location

• The cold frontal slope is likely to be close to the average 1:50

• Cold front is neither Katabatic or Anabatic



DCB

Cold Frontal Cross-section along Poleward Branch of the Dry Conveyor Belt (DCB)

Cold air in Cold Conveyor Belt (CCB) becoming less deep and less moist compared to the left of the flow

Warm Conveyor Belt (WCB) is still probably deep, warm and moist

CCB nearly a straight flow with weakening cold advection

Mixing Zone

SurfaceCold Front

Frontal slope is near the typical 1:50

WCB oriented for

less frontal lift

Common area for deep instability

A

B

A B


WCBCCB

Winds nearly straight above the frontal zone indicative of a cold front which is neither anabatic or katabatic

Behind the Cold Front Conceptual ModelsCentered on the Col looking along the flow.


DCB Centred on the ColC


Mixing layer

Dry CB

Within the DCB:•Nil VWS


The Cold Screaming Eagle CM

Both of the eagle’s wings are fully extended.

oRight WingLeft Wing


A B


The Cold Screaming Eagle CMThis is a placeholder for a real example. o

Right WingLeft Wing


Equatorward of DCB

• The DCB tends to sink isentropically as it typically curls anticyclonically toward the south

• Typically along the equatorward tip of the comma tail

• Winds typically veer with height above the cold frontal surface

• The cold frontal slope is more shallow than the average 1:50

• Cold front is likely Katabatic



DCB

Cold Frontal Cross-section along Equatorward Branch of the Dry Conveyor Belt (DCB)

Cold air in Cold Conveyor Belt (CCB) shallow and dry. Precipitation will be lacking for radar coverage.

Warm Conveyor Belt (WCB) is shallow, warm and moderately moist

CCB probably veers backs with height consistent with warm advection … I know this seems odd.

Mixing Zone

SurfaceCold Front

Frontal slope is more shallow than the typical 1:50

WCB oriented for

less frontal lift

Common area for deep instability A

B

A B


WCBCCB

Veering winds above the frontal zone indicative of katabatic cold front

Behind the Cold Front Conceptual ModelsRight of the Col looking along the flow.


DCB Centred on the ColC


Mixing layer

Dry CB

Within the DCB:•Winds veer with range/height to the west•Katabatic cold front


The Cold Left Wing Dive CMThe eagles left wing is folded forward as if it is about to turn to the right and swoop down. That is what this part of the DCB does.The right wing is still fully extended to catch the lift of the WCB.

oRight WingLeft Wing


AB


The Cold Left Wing Dive CMThis is a placeholder for a real example. o

Right WingLeft Wing


Cross Section of Inactive Cold Front


Inactive or Katabatic Cold Front


DCB

Cold Frontal Cross-section along Poleward Branch of the Dry Conveyor

Belt (DCB)

Cold air in Cold Conveyor Belt (CCB) shallow and dry

Warm Conveyor Belt (WCB) is shallow, warm and moist

CCB veers with height (consistent with warm advection – weakening cold advection?)

Mixing Zone

SurfaceCold Front

Frontal slope is shallower than the typical 1:50

WCB oriented for

less frontal lift

Common area for shallow instability if any

A

B

A B

WCB just ahead of cold front also typically backs with height

WCBCCB

Veering winds above the frontal zone indicative of katabatic cold front

Radar Palette Home Click Doppler

Cross Section of Inactive Cold Front

The cold frontal cloud tends to be ahead of the inactive, katabatic cold front

Radar Palette Home Click Doppler

Inactive or Katabatic Cold Front


Vertical Deformation Zone Distribution and the CBMSummary

C

C

C

C

C

DC

B

DCB

CCB

DCB

C


This must be and remain as Slide 31.

• The links to the three sections of the airflows that comprise each of the conveyor belts are located at Slide 1,11 and 21.

• Slide 11 is always the central, col limited circulation.

• This leaves 10 PowerPoint slides for the development of the training material which should be more than adequate.

radar palette home click doppler post cold frontal 1 poleward dcb the dcb tends to rise...

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