locally heavy rainfall event: the set-up
DESCRIPTION
Strong NE Flow converged along the NE Florida coast following the passage of a slow moving backdoor front. There was adequate instability across the forecast area to support convection…but a trigger was need to initiate shower activity. IMAGE from 10 pm 9/16: Surface wind barbs (black) - PowerPoint PPT PresentationTRANSCRIPT
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Locally Heavy Rainfall Event: The Set-Up
• Strong NE Flow converged along the NE Florida coast following the passage of a slow moving backdoor front.
• There was adequate instability across the forecast area to support convection…but a trigger was need to initiate shower activity.
IMAGE from 10 pm 9/16:Surface wind barbs (black)Surface Based CAPE (measure of instability): Contours/Color Image
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Locally Heavy Rainfall Event: The Set-Up
• Strong NE Flow converged along the NE Florida coast following the passage of a slow moving backdoor front.
• There was the potential for heavy rainfall in convection due to high moisture content and slow storm motion.
Image: 00Z 9/17 Jacksonville Sounding
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Locally Heavy Rainfall Event: The Events
KJAX 0.5 Z at 22:59Z 9/16 KJAX 0.5 Z at 00:58Z 9/17 KJAX 0.5 Z at 03:02Z 9/17
• Two distinct bands of convection developed late last night. The first band extended N-S from northern Columbia county to eastern Alachua.
• It is possible that as the line inland intensified and created locally low pressure, NE convergence was increased along the coast and thus intensified convection across Duval and northern St. Johns counties.
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Locally Heavy Rainfall Event: The Results
IMAGE: Storm Total Precipitation (inches) from the Valdosta Radar (KVAX) from last nights rainfall event.
- Widespread 3-4 inches (yellow)
- Locally 6-10 inches (white & purple)
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Locally Heavy Rainfall Event: The Results
IMAGE: Storm Total Precipitation (inches) from the Valdosta Radar (KVAX) from last nights rainfall event.
• Ground Truth reports confirm much of Arlington received 7-8 inches of rainfall
• Locations near Jacksonville Beach received around 9 to 9.5 inches.