Purpose

• To deepen your knowledge to use satellite images for practical nowcasting during situations of summer convection Model monitoring Interpretation of relevant structures Optimal utilisation of different kind of data

radar, NWP, radiosoundings, synops

Pre-requesites

• Pre-reading of material and quiz in relation to "Convection"

• Online-presentation

Content

1. Repition conceptual models– Diagrammes– How it looks in satellite images, typical structures

2. Nowcasting process– Pre-warning– Interpretation of satellite images– combination with radar (briefly)

3. Group work and discussions

Conceptual models

Typical hodographs

single cell

multi cell

super cell

Development stages of single cells

Radar echos within a multi cell

WER = Weak Echo Region

Cross section of a super cell

gust front

hail

hailrain

gust clouds

Windspeed

Height

(km)

Height

(km)

Movement of the system: from left to righthorizontal hatched: updraft, vertical hatched: radar echo of more than 10³ mm6m-3

Right diagramm: wind speed relatively to the movement of the super cell

Overshooting possible

Radar echos within a squall-line

NOAA-VIS, 28.05.99, 14 UTC: Convective structures

Multicells, cirrus shield spreaded to the NE according to high level wind

Single cells

Super cells, first overshootings

Squall-line development

V-Notch: NOAA IR 10.8 μm (02.06.99, 14:52 UTC)

Video

V-Notches:tip directed to SW

and to SE, repectively

Squall-Line: NOAA IR 10.8 μm (02.06.1999, 17:25)

Squall-Line: NOAA VIS 0.8 μm (02.06.1999, 17:25)

Overshootings

Bow structure

MCC: NOAA 0.8 μm (28.05.99, 17:36 UTC)

Overshootings

MCC: NOAA IR 10.8 μm (28.05.99, 17:36 UTC)

Nowcasting - process

Pre-warning (NWP-fields), here onlysurface pressure+ equivalent potential temperature (850 hPa)

KO-index + vertical velocity in 500 hPa

Pre-warning (radiosoundings)

Radiosoundings (Middle Europe): KO + Wind 850 hPa

present situation: potential instability

Radiosounding (SW-Germany): Measurement + evaluation

GME+06h (02-06-09, 06 UTC):NWP-field okay? / which conceptual model?

Airmass-RGB + potential vorticity 330 K (near tropopause)

GME+12h (02-06-09, 12 UTC)KO-Index and vertical motion (500 hPa)(Two critical areas over / near Germany)

GME+12h (02-06-09, 12 UTC)Surface pressure and Theta (850 hPa)

(Two convergences over / near Germany)

Nowcasting up to 6 hours(which conceptual models can be used)

Convection at leading edge of frontal cloud band (from Satmanu)

Convection by PV-triggering (from Satmanu)

PV-max PVAconvection

PVA

movement

Airmass-RGB + PV at 330 KEllipse: Convection at leading edge of frontal cloud bandsArrows: PV-maxima 6 hours later Convection by PV?

2-6-09, 06 UTC: Surface pressure tendencies (hPa/10/3h) + 10 m wind + Water vapour 6.2 μm

Weather monitoringand nowcasting

Utilisation of different products (beginning convection)(02-06-2009)

HRV: 9:30 Radar (1km): 9:45 IR-CTT < -25°C: 10:15

RGB "Airmass": 11:30(becoming less suitable – not further used)

RGB "Severe convection": 11:30(becoming more important)

!!

less dangerous

2-6-09, 12:30 UTC: 10 m wind + "Severe convection"

2-6-09, 12:30 UTC: 10 m wind + IR-enhanced (hail possible)

2-6-09, 14 UTC: Surface pressure tendencies (hPa/10/3h) (decreasing, increasing) + 10 m wind + HRV

2-6-09, 14:30 UTC: 10 m wind + IR-enhanced (V-structure)

2-6-09, 14:30 UTC: Information from different remote sensing(strong convection)

9 km

9 km

hail likely, cell's mature stage

HRV: overshooting severe convection, cells' development southeast

IR-enhanced: V-structure severe convection, cells' development southeast

"severe convection": small ice particles at SE edge of big complex strongest updraft.

New cells SE of it, small yellow area development potential.

Doppler: gusts at least 35 knots, observation network: "only" 19 knots

2-6-09, 18 UTC: Surface pressure tendencies (hPa/10/3h) + (decreasing, increasing) + 10 m wind + HRV

Increasing surface pressure convection's weakening

Summary

1. For "early warning"– NWP (monitoring with corresponding measurments and/or satellite images)– NWP: Regions of convection– Radiosoundings

2. Nowcasting– before clouds develop and during convection's onset: Airmass / WV

• some hours before hints to probable convection (consider also the movement of relevant structures (PV-maxima))

– HRV with first hints, followed by a) radar b) IR and composites– After convection started

• Airmass and WV with reduced benefit• "Severe convection" very helpful for development's potential• IR: hail, V-structures (according enhancement)• HRV: Overshootings, most active convection, V-structure, bow-structure• Fine structure: radar• Thunderstorms: Lightning detection

• Observations / measurements, of course!