PREDICT Synopsis - Another Interaction Like Colin Formation
Posted by JAC on 8/3/2010, 9:07 am
PREDICT pouch synopsis

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Date (UTC): 2010/08/03 11:35
Author: Boothe
Submitted at (UTC): 2010/08/03 11:58
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Pouch Name: PGI24L        Official Name:        Initial Center Point: 14N   18W
Notes:

Several days ago, PGI21L moved off of Africa and passed north
and close to the convectively active PGI22L, helping to develop
PGI22L into what is now TS Colin.
Now, there is a similar scenario with a convectively active ITCZ
and PGI24L coming off of Africa.  The models suggest that the
initial 700hPa wave will dissipate but that subsequent
development occurs in the ITCZ.


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ECMWF:  Phase Speed:        Determination:        Level tracked:


GFS:      Phase Speed: -6.6        Determination: Moisture & v average        Level tracked: 700 hPa

The v700/v850/v925 hovmoller diagram depicts southerlies
(positive v) already established over the Atlantic at 925 & 850
hPa with the 700-hPa trof with its southerlies moving in from
the east.
The moisture and v700 hovmollers also hint a fast initial motion
followed by slower westward motion.
I connected the positions of the initial 700-hPa pouch and the
subsequent development of the system in the ITCZ; hence the
disjointed track.


UKMET:  Phase Speed:        Determination:        Level tracked:



NOGAPS:  Phase Speed: -4.1        Determination: RH only        Level tracked: 700 hPa

Phase speed is a bit slow, but the v700 signal is very weak. (A
test of -7.1m/s gave a better depiction of a pouch at analysis
time, but just at analysis time.)
NOGAPS quickly dissipates the 700-hPa pouch, and then it
develops multiple ITCZ, but the temporal gap between the two
events is too great to create a track.



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Other potential systems:
PGI20L wave over Belize at 00Z.

Hints of PGI21L still persist in the first 36 h of the
PGI22L/TD04L GFS fields, just to the northwest of TD04L.

Convection southeast of TD04L (Colin) may play a role in an
interaction with PGI24L in the coming days.




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In this thread:
Wave PGI24L about to exit Africa - JAC, 8/2/2010, 12:01 pm
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