000
AXPZ20 KNHC 182117
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 18 2008

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 04N77W 02N93W 05N111W 03N125W 
03N140W. SCATTERED SHOWERS FROM 04N-07N BETWEEN 78W-80W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 01N-05N 
BETWEEN 85W-97W. SCATTERED SHOWERS FROM 04N-06N BETWEEN 
101W-107W. SCATTERED MODERATE FROM 02N-07N W OF 135W.

...DISCUSSION...

W OF 110W...
A STAGNANT PATTERN REMAINS ENTRENCHED OVER THE WESTERN HALF OF 
THE DISCUSSION AREA...HIGHLIGHTED BY BROAD MID/UPPER LEVEL 
TROUGHING LYING W OF 120W. A MID/UPPER LOW REMAINS EMBEDDED IN 
THE TROUGH NEAR 22N138W AND IS BOUNDED BY THE SUBTROPICAL JET 
WHICH EXTENDS FROM 10N140W NEWD TOWARDS NORTHERN BAJA 
CALIFORNIA. A SHORTWAVE TROUGH IN THE MID-LATITUDES IS LOCATED 
JUST W OF CALIFORNIA WITH ITS AXIS EXTENDING INTO THE AREA FROM 
30N130W TO THE AFOREMENTIONED MID/UPPER LOW...AND A BRANCH OF 
THE POLAR JET DIVES AROUND THIS TROUGH ULTIMATELY MERGING WITH 
THE SUBTROPICAL JET W OF NORTHERN BAJA. MODERATE/STRONG 
SUBSIDENCE LIES W OF A LINE FROM 30N120W TO 18N140W AND THE 
RESULTING INVERSION IS SUSTAINING A BROKEN STRATOCUMULUS FIELD W 
OF 122W. FARTHER S...AN UPPER TROUGH AXIS EXTENDS FROM 12N126W 
TO 02N110W WITH THE SURROUNDING FLOW TURNING SHARPLY FROM 
WESTERLY TO SOUTHERLY IN ITS VICINITY. AS A RESULT...WEAK 
DOWNSTREAM DIFFLUENCE IS ENHANCING SHOWER ACTIVITY ALONG THE 
ITCZ.

E OF 110W...
THE EASTERN HALF OF THE AREA IS DOMINATED BY MODERATE MID/UPPER 
LEVEL RIDGING WHICH IS CENTERED NEAR ACAPULCO MEXICO. STRONG 
WESTERLIES LIE N OF THE UPPER HIGH WHERE JET CORE SPEEDS OF 
60-80 KT ARE RACING ACROSS NORTHERN MEXICO WITH AN EXCEPTIONALLY 
DRY AIR MASS EXTENDING FROM THE PACIFIC COAST EWD. AS 
SUCH...SKIES ARE VIRTUALLY CLOUDLESS OVER THE MEXICAN PLATEAU. 
STRONG SUBSIDENCE OVER THE AREA IS EXPECTED TO WEAKEN OVER THE 
NEXT 48 HRS AND COULD FOSTER GREATER SHOWER COVERAGE OVER THE 
WEEKEND. SUBSIDENCE EXTENDS FARTHER S ACROSS SOUTHERN MEXICO... 
CENTRAL AMERICA...AND THE ADJACENT WATERS WITH NEARLY CLOUDLESS 
SKIES OVER THE AREA. DEEPER MOISTURE BEGAN MOVING W FROM 
COLOMBIA TODAY AND DEEP CONVECTION DEVELOPED S OF THE GULF OF 
PANAMA. THIS TREND IS EXPECTED TO CONTINUE OVER THE NEXT FEW 
DAYS WITH AREAS OF CONVECTION DEVELOPING FROM TIME TO TIME NEAR 
THE ITCZ AXIS MAINLY E OF 90W.

$$
BERG