000
AXPZ20 KNHC 141526
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON SEP 14 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1415 UTC.

...SPECIAL FEATURES...

A DEEP LAYER TROUGH IS CENTERED ALONG 110W BETWEEN 05N AND 20N 
WITH A SURFACE LOW FOUND AT 10N110W...EMBEDDED IN THE ITCZ. THE 
0340 UTC AND 0520 UTC ASCAT PASSES SHOW AN AREA OF S TO SW FLOW 
IN THE 20 TO 25 KT RANGE S OF THE ITCZ FROM 102W TO 
115W...FEEDING TROPICAL MOISTURE INTO THE CIRCULATION. AN AREA 
OF NUMEROUS MODERATE TO STRONG CONVECTION CAN BE FOUND NE OF THE 
LOW WITHIN 120 NM OF 15N108W. THIS SYSTEM IS UNDER A MODERATELY 
DIFFLUENT PATTERN BETWEEN THE UPPER LEVEL ANTICYCLONE CENTERED 
NEAR 20N110W AND THE NW EDGE OF THE BROAD UPPER TROUGH TO THE 
SE. DEEP CONVECTION IS EXPECTED TO BE SUSTAINED UNDER  
PERSISTENT UPPER LEVEL DIFFLUENCE AS THE SYSTEM TRACKS WESTWARD 
FOR AT LEAST THE NEXT TWO DAYS.

...TROPICAL WAVES...

A TROPICAL WAVE IS ANALYZED ALONG 102W N OF 07N TO THE MEXICAN 
COAST MOVING W AT 15 KT. SCATTERED MODERATE CONVECTION CAN BE 
FOUND WITHIN 120 NM OF THE COAST FROM 99W TO 106W.

A TROPICAL WAVE IS ANALYZED ALONG 114W/115W FROM 05N-16N MOVING 
W 10 KT. SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 180 
NM E OF THE WAVE AXIS N FROM 12N TO 16N.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE 07N77W TO 
06N85W TO 14N100W TO 10N110W TO 06N140W. SCATTERED MODERATE TO 
STRONG CONVECTION IS WITHIN 120 NM S AND 60 NM N OF THE ITCZ 
AXIS FROM 125W TO 137W. 

...DISCUSSION...

N OF 20N....THE HIGHLY AMPLIFIED DEEP LAYER TROUGH CURRENTLY 
OVER THE WESTERN CONTINENTAL U.S. IS BEGINNING TO TURN NEGATIVE 
TILT. AS THE SOUTHERN EDGE OF THE DEEP LAYER TROUGH LIFTS 
NE...RIDGING WILL BUILD TO ITS S AND THE SURFACE COLD FRONT 
CURRENTLY FROM 30N124W TO 27N133W WILL DISSIPATE. THE AREA IS 
CURRENTLY DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS WITH 
OVERCAST STRATOCUMULUS. ON TUESDAY...A STRONG MIDDLE LATITUDE 
TROUGH WILL APPROACH NW FORECAST WATERS. THIS TROUGH WILL LIFT 
THE REMNANT LOW OF LINDA...CURRENTLY NEAR 
20N135W...NORTHWESTWARD AND SHEAR THE LOW LEVEL CIRCULATION. THE 
0250 UTC QUIKSCAT PASS SHOWED WINDS STILL OVER 20 KT IN THE NW 
QUADRANT OF THE REMNANT LOW.

S OF 20N...ASIDE FROM THE AFOREMENTIONED SPECIAL FEATURE...THE 
TWO TROPICAL WAVES...AND THE CONVECTION ALONG THE 
ITCZ...CONDITIONS ARE RELATIVELY QUIET OVER THE REMAINDER OF THE 
AREA. SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 150 NM 
OF THE COAST OF COSTA RICA AND NICARAGUA FROM 08N TO 12N. THIS 
CONVECTION LIES IN THE JET EXIT REGION OF THE 40 KT UPPER LEVEL 
NORTHEASTERLY JET ACROSS HONDURAS AND EXTENDING SW TO 00N103W.  
THE SHEAR INDUCED BY THIS JET IS INHIBITING CONVECTION ALONG THE 
ITCZ BETWEEN THE EASTERN TROPICAL WAVE AND 90W.

$$
SCHAUER CLARK