000
AXPZ20 KNHC 271517
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI APR 27 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N77W 8N100W 6N110W 8N118W 7N140W. 
SCATTERED MODERATE CONVECTION WITHIN 60 NM OF AXIS BETWEEN 
82W-86W. SCATTERED MODERATE WITHIN 60 NM OF 11N104W AND 9N122W. 
SCATTERED MODERATE/ISOLATED STRONG WITHIN 45 NM OF AXIS W OF 
137W.

...DISCUSSION...

SUBTROPICS...
THE SUBTROPICAL JET IS WEAVING ITS WAY ACROSS THE AREA FROM 
23N140W TO THE TOP OF A WEAK RIDGE NEAR 26N134W...THEN TO THE 
BASE OF A TROUGH NEAR 20N118W...THEN NE INTO NRN MEXICO. A 
DEEP-LAYERED CUT-OFF LOW IS LOCATED OVER THE BAJA PENINSULA NEAR 
29N115W AND IS BEING PUSHED SLIGHTLY SSE BY A STRONG UPPER RIDGE 
OVER CALIFORNIA. STRONG CONFLUENCE INTO THE BASE OF THE 
TROUGH/LOW IS PRODUCING MODERATE/STRONG SUBSIDENCE N OF 20N 
BETWEEN 110W-125W...AND THE INVERSION IS PRODUCING AN ALMOST 
OVERCAST STRATOCUMULUS FIELD W OF 112W. OVER MEXICO...SOME 
FOG/LOW CLOUDS ARE HANGING ALONG THE WRN BAJA COAST DUE TO THE 
STRATOCU FIELD...AND CLOUDS ARE HANGING ALONG THE SIERRA MADRE 
OCCIDENTALS DUE TO THE EFFECTS OF THE SUBTROPICAL JET.

TROPICS...
A MID-LEVEL RIDGE EXTENDS ACROSS THE TROPICAL REGION ALONG 13N W 
OF 110W AND IS TRANSLATING INTO ONLY MODERATE SUBSIDENCE NEAR 
THE CENTER OF THE HIGH NEAR 14N127W. THERE IS VERY LITTLE UPPER 
DIFFLUENCE OVER THE AREA WHICH IS KEEPING THE ITCZ MOSTLY LINEAR 
AND WITHOUT WIDESPREAD CONVECTION. E OF 120W...THE UPPER 
LOW/TROUGH NEAR BAJA IS DRAWING A CIRRUS SHIELD NE TOWARDS 
MEXICO...WHICH THEN ERODES WHEN IT REACHES AN AREA OF SUBSIDENCE 
OVER SE MEXICO. AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 
10N110W AND CONTINUES TO DRAW SOME OF THE DRIER AIR OVER THE SRN 
GULF OF MEXICO SWD OVER THE PACIFIC WATERS...ALTHOUGH THE AREA 
IS DOTTED WITH CONVECTIVE CELLS THAT HAVE BEEN ABLE TO PENETRATE 
THE STABLE LAYER. MOISTURE INCREASES AGAIN E OF 90W DUE TO 
ANOTHER ANTICYCLONE OVER VENEZUELA WITH THE FLOW DRAWING WATER 
VAPOR NWD ACROSS COLOMBIA AND THE ADJACENT WATERS.

$$
BERG