CASE 14 - Intense cells form along seabreeze boundary

7/29/04

Microphysical scans 2030 - 2230 Z, 2h

(System lifetime: 1840 - 2300 Z)

 

 

SYNOPTIC CONDITIONS SUMMARY:

 

Synoptic feature map -

IOP status - IOP4 in effect (see report). The main objective of this IOP was to study the predicted break in monsoonal flow, which indeed occurred. Another objective of this IOP was to study seabreeze fronts, which were expected to form due to predicted clear skies. A moisture-flux investigation flight was flown on 7/29 1636-2331 Z (see P-3 report), and seabreeze fronts were sampled along the east coast of GOC.

 

Dominant features - N-S oriented 200 mb anticyclone just west of Baja Peninsula and NE-SW oriented 200 mb anticyclone extending from LA through central Mexico.

 

Cyclone set up between anticyclones and associated ridges - over southern GOC.

 

 

 

 

 

Day 0 forecast discussion text

 

Winds (Eta)

200 mb - model.ETA.200407291200.00_200mb_wnd.gif - model.ETA.200407291200.06_200mb_wnd.gif

500 mb - model.ETA.200407291200.00_500mb_wnd.gif - model.ETA.200407291200.06_500mb_wnd.gif

700 mb - model.ETA.200407291200.00_700mb_wnd.gif - model.ETA.200407291200.06_700mb_wnd.gif

850 mb - model.ETA.200407291200.00_850mb_wnd.gif - model.ETA.200407291200.06_850mb_wnd.gif

 

 

 

EVENT SUMMARY:

 

24 h precipitation totals -

 

2024 Z, GOES-10 Vis

 

S-POL SUMMARY:

 

SCAN OVERVIEW:

 

1715 - 1830 Z

Running ClimoShallow: Fine seabreeze front moves ashore, passing over S-Pol.

 

1815Z, Base reflectivity

 

1841 Z

Cells popping up along seabreeze front. Cells at ~120 km topping at 12 km.

 

1845Z, Base reflectivity

 

1845 Z

Switching to ClimoFar: Cells along seabreeze front are looking respectable. Seabreeze convection is moving towards the SE - towards S-Pol.

 

2015 Z

Switching to ClimoNear: Seabreeze cells are moving closer to S-Pol.

 

2030 Z

Begin Microphysical Scanning, Switching to MicroNear135: Centered sector scans on 15 deg.

 

2039 Z

Storm to N/NW is visually impressive, with symmetric anvil and cumuli in foreground.

 

2039Z, GOES-10 Thermal IR

 

2140 Z

Changed sector to 140 deg: Convection forming to the S/SE, so sector was shifted to capture new growth. Storm at 42 deg shows nice low-level velocity couplet.

 

2145Z, Base reflectivity

 

2225 Z

End Microphysical Scans, Switching to ClimoNear:

 

2333 Z

Outflows merged into a strip parallel to coast and look like another sea breeze front. Storms firing everywhere except in north quadrant where old storms were (nothing over ocean).