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Forecasting Technique: Pattern Recognition
• Associating a “weather pattern” to a “weather event”
• Significant weather events have patterns– surface features
– upper level features
– 4-panel maps useful
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Pattern Recognition: Severe Weather
• Dynamics– Wind-driven
• Thermodynamics– Stability-driven
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Pattern Recognition: Severe Weather
• Dynamics (winds)– Shortwaves
• jet streaks, vortmax’s
– Fronts• mech. lift
• Thermodynamics (stability)– LI’s, CAPE– Low-level moisture (Td’s)
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Severe1: Severe WX Reports
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Severe1: 500mb
Potentshortwaveapproaching- > 28 max-> cold air
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Case 1: 700mb
Slight drypunch at700mb->pot inst
Vigorousflow at700mb
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Case 1: Surface
Cold frontapproaching
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Case 1: ETA Lifted Index
Apex/tongue oflow stabilityair
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Case 1: ETA/NGM Precipitation
Local max higher in ETA Local max lower in NGM
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Case 2: Severe Wx. Reports
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Case2: 4-PANEL MAP, 18Z
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Case2: 4-PANEL MAP, 00Z
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Change of 700mb UVV
Signature of Intensification!
18z 00z
Case2: CHANGE OF Vertical Velocity
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Case2: Lifted Index
Apex/tongue oflow stabilityair
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Severe2: Sounding
Is this sounding conducive for deep convection?
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Severe2: Surface features
High Td’s+High T’s = High
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Other patterns
• Strong shortwave coming from the Rockies– Adds additional lift– Brings the dryline into play– Can draw high theta-e air north from Gulf– Warming on Front Range of Rockies from
downsloping