MADISON’S CURRENT WEATHERMADISON’S CURRENT WEATHER

Madison Weather at 1000 AM CDT TUE AUG 7 2001 Updated twice an hour at :05 and :25

Sky/Weather: SUNNY Temperature: 85 F (29 C) Dew Point: 76 F (24 C) Relative Humidity: 74% Wind: VRB7 MPH Barometer: 30.13F

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 33

Surface Weather Map from Today Surface Weather Map from Today with with IsobarsIsobars & Fronts & Fronts

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 44

Current Temperatures (Current Temperatures (ooF) & IsothermsF) & Isotherms

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 55

Current Dewpoints Current Dewpoints ((ooF) F)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 77

Current Winds Aloft at 34,000 Ft.Current Winds Aloft at 34,000 Ft.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 1111

Tomorrow’s 7AM ForecastTomorrow’s 7AM Forecast

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 1212

ATM OCN 100 - Spring 2002 ATM OCN 100 - Spring 2002 LECTURE 25 LECTURE 25 (con’t.)(con’t.)

MID-LATITUDE WEATHER SYSTEMS:MID-LATITUDE WEATHER SYSTEMS:PART II: THE EXTRATROPICAL CYCLONEPART II: THE EXTRATROPICAL CYCLONE

A.A. IntroductionIntroductionB.B. The Norwegian Model of Extratropical CyclonesThe Norwegian Model of Extratropical CyclonesC.C. Observed Weather Features surrounding Observed Weather Features surrounding

Extratropical CyclonesExtratropical CyclonesD.D. Life Cycle of an Extratropical CycloneLife Cycle of an Extratropical Cyclone

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Life Cycle of an Extratropical CycloneLife Cycle of an Extratropical Cyclone See Fig. 11.9 Moran & Morgan (1997)See Fig. 11.9 Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3434

Incipient Cyclone Stage in the Life Incipient Cyclone Stage in the Life Cycle of an Extratropical CycloneCycle of an Extratropical CycloneSee Fig. 11.9A Moran & Morgan (1997)See Fig. 11.9A Moran & Morgan (1997)

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The Surface Low & the JetThe Surface Low & the Jet

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Linkage between surface weather Linkage between surface weather systems & winds aloftsystems & winds aloft

See Fig. 10.22 Moran & Morgan (1997)See Fig. 10.22 Moran & Morgan (1997)

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Wave Cyclone Stage in the Life Cycle Wave Cyclone Stage in the Life Cycle of an Extratropical Cycloneof an Extratropical Cyclone

See Fig. 11.9B Moran & Morgan (1997)See Fig. 11.9B Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3838

Occluding Stage in the Life Cycle of an Occluding Stage in the Life Cycle of an Extratropical CycloneExtratropical Cyclone

See Fig. 11.9C Moran & Morgan (1997)See Fig. 11.9C Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3939

Bent-Back Occlusion Stage in the Life Bent-Back Occlusion Stage in the Life Cycle of an Extratropical CycloneCycle of an Extratropical CycloneSee Fig. 11.9D Moran & Morgan (1997)See Fig. 11.9D Moran & Morgan (1997)

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Cyclone Families from TIROSCyclone Families from TIROS

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Occluded Cyclone over British Occluded Cyclone over British IslesIsles

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E. MOVEMENTS OF EXTRATROPICAL E. MOVEMENTS OF EXTRATROPICAL WAVE CYCLONESWAVE CYCLONES

General MovementsGeneral Movements

– Steering winds aloftSteering winds aloft

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Zonal Circulation RegimeZonal Circulation RegimeFigure 10.10 Moran & Morgan (1997)Figure 10.10 Moran & Morgan (1997)

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Meridional Circulation RegimeMeridional Circulation RegimeFigure 10.10 Moran & Morgan (1997)Figure 10.10 Moran & Morgan (1997)

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Stagnant Circulation Regime Stagnant Circulation Regime with with Cut-off Lows & Blocking HighsCut-off Lows & Blocking Highs

Figure 10.13 Moran & Morgan (1997)Figure 10.13 Moran & Morgan (1997)

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E. MOVEMENTS OF EXTRATROPICAL E. MOVEMENTS OF EXTRATROPICAL WAVE CYCLONES WAVE CYCLONES (con’t.)(con’t.)

General MovementsGeneral Movements Regions of CyclogenesisRegions of Cyclogenesis

– Lee-side of mountainsLee-side of mountains

– Along east coasts of continentsAlong east coasts of continents

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Lee-slope CyclogenesisLee-slope CyclogenesisSee Fig.1 pg. 275, Moran & Morgan (1997)See Fig.1 pg. 275, Moran & Morgan (1997)

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E. MOVEMENTS OF EXTRATROPICAL E. MOVEMENTS OF EXTRATROPICAL WAVE CYCLONES WAVE CYCLONES (con’t.)(con’t.)

General MovementsGeneral Movements Regions of CyclogenesisRegions of Cyclogenesis

– Lee-side of mountainsLee-side of mountains

– Along east coasts of continentsAlong east coasts of continents Principal Cyclone Tracks overPrincipal Cyclone Tracks over

North America North America

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Storm TracksStorm Tracks see Fig. 11.16 of Moran & Morgan (1997)see Fig. 11.16 of Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5454

E. MOVEMENTS OF EXTRATROPICAL E. MOVEMENTS OF EXTRATROPICAL WAVE CYCLONES WAVE CYCLONES (con’t.)(con’t.)

General MovementsGeneral Movements Regions of CyclogenesisRegions of Cyclogenesis Principal Cyclone Tracks overPrincipal Cyclone Tracks over

North America North America Time Sequences of Weather Events -Time Sequences of Weather Events -

Single Point Forecasting Single Point Forecasting

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5555

Weather along Storm TracksWeather along Storm Tracks(A) Warm Side(A) Warm Side vs. vs. (B) Cold side (B) Cold side

see Fig. 11.15 of Moran & Morgan (1997)see Fig. 11.15 of Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5656

Weather on Warm SideWeather on Warm Side

Windy, warm & rainy in Windy, warm & rainy in Madison Madison

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5757

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5858

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5959

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6060

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6161

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6262

Weather on Cold SideWeather on Cold Side

Development of a 5 inch snow Development of a 5 inch snow storm in Madison (with storm in Madison (with

temperatures in the teens)temperatures in the teens)

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ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6464

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6565

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6767

Incipient Cyclone Stage in the Life Incipient Cyclone Stage in the Life Cycle of an Extratropical CycloneCycle of an Extratropical CycloneSee Fig. 11.9A Moran & Morgan (1997)See Fig. 11.9A Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6868

Wave Cyclone Stage in the Life Cycle Wave Cyclone Stage in the Life Cycle of an Extratropical Cycloneof an Extratropical Cyclone

See Fig. 11.9B Moran & Morgan (1997)See Fig. 11.9B Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6969

Occluding Stage in the Life Cycle of an Occluding Stage in the Life Cycle of an Extratropical CycloneExtratropical Cyclone

See Fig. 11.9C Moran & Morgan (1997)See Fig. 11.9C Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7070

Bent-Back Occlusion Stage in the Life Bent-Back Occlusion Stage in the Life Cycle of an Extratropical CycloneCycle of an Extratropical CycloneSee Fig. 11.9D Moran & Morgan (1997)See Fig. 11.9D Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7171

G. WINTER STORMSG. WINTER STORMS

DefinitionsDefinitions Winter Weather ConditionsWinter Weather Conditions

– Hazards of Winter StormsHazards of Winter Storms HEAVY SNOWHEAVY SNOW ICE STORMSICE STORMS STRONG WINDSSTRONG WINDS

– Ingredients of a Winter StormIngredients of a Winter Storm COLD AIRCOLD AIR MOISTUREMOISTURE LIFTLIFT

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See Figure 11.14 Moran & Morgan (1997)See Figure 11.14 Moran & Morgan (1997)

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WINTER STORMS WINTER STORMS (con’t.)(con’t.)

BlizzardsBlizzards

– Winter weather condition lastingWinter weather condition lasting 3 hours 3 hours oror more with: more with: Strong winds (35 mph or more);Strong winds (35 mph or more); Snow & blowing snowSnow & blowing snow

with visibility less than 1/4 mile. with visibility less than 1/4 mile.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7474

WINTER STORMS WINTER STORMS (con’t.)(con’t.)

Public Information DisseminationPublic Information Dissemination & Public Safety Precautions & Public Safety Precautions

– Blizzard warnings;Blizzard warnings;

– Winter storm watches & warnings;Winter storm watches & warnings;

– Ice storm warnings;Ice storm warnings;

– High wind warnings;High wind warnings;

– Wind chill warnings.Wind chill warnings.

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Cyclones along the Polar FrontCyclones along the Polar Front

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Cross Section thru a cycloneCross Section thru a cyclone

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An extratropical cycloneAn extratropical cyclone

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Typical cyclone tracksTypical cyclone tracks

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