000
AXPZ20 KNHC 232132
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 23 2010

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 
2000 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 05N80W TO 
07N106W TO 04N123W TO 07N130W TO 05N140W. SCATTERED MODERATE TO 
STRONG CONVECTION WAS WITHIN 180 NM S OF AXIS E OF 87W. A 1006 
MB LOW PRES SYSTEM WAS ON THE E EDGE OF THE ITCZ AT 05N80W NEAR 
THIS STRONG CONVECTION AND HAD SCATTERED MODERATE WITHIN 120 NM 
OF ITS N QUADRANT. A TROUGH WAS EMBEDDED IN THE ITCZ 10N108W TO 
03N113W AND THERE WAS SCATTERED MODERATE CONVECTION WITHIN 270 
NM E OF THE TROUGH N OF 06N.

...DISCUSSION...
A MID TO UPPER LEVEL LOW CENTERED E OF THE CENTRAL ROCKIES DRAGS 
A TROUGH SOUTHWESTWARD INTO THE DESERT SW U.S. AND NW MEXICO. 
THE SURFACE COLD FRONT HAS MOVED THROUGH THE SOUTHERN PLAINS AND 
THE PRES GRADIENT BETWEEN THIS TROUGH AND 1030 MB HIGH PRES N OF 
THE AREA NEAR 35N139W HAS SLACKENED CONSIDERABLY OVER THE PAST 
24 HOURS. STRONGEST WINDS ASSOCIATED WITH THIS PATTERN NOW LIE 
NEAR THE SOUTHERN TIP OF BAJA CALIFORNIA JUST N OF THE RIDGE 
AXIS THAT EXTENDS FROM THE HIGH CENTER TO NEAR 18N110W. AS THE 
COLD FRONT MOVES S THROUGH EASTERN MEXICO OVER THE 
WEEKEND...LOOK FOR THE STRONGEST PRES GRADIENT TO SHIFT S AS 
WELL...CAUSING THE 20 KT WINDS TO SHIFT S TO THE COASTAL AREA 
NEAR MANZANILLO. SIMILARLY...THE PRES GRADIENT S OF THE HIGH 
BETWEEN IT AND THE ITCZ HAS INDUCED FRESH EASTERLY TRADE WINDS 
OVER W WATERS ACCORDING TO THE 1822 UTC ASCAT PASS. THE HIGH 
PRES SYSTEM IS FORECAST TO CONTINUE TO WEAKEN AS IT IS NUDGED 
SOUTHEASTWARD OVER THE NEXT TWO DAYS BY A COLD FRONT PASSING 
OVER ITS NW EDGE. TRADE WINDS WILL SHRINK IN AREA THE NEXT FEW 
DAYS IN RESPONSE TO THE WEAKENING HIGH PRES TO THE N.

THERE WERE TWO TROUGHS EMBEDDED IN THE ITCZ AT 1800 UTC. THE 
WESTERN TROUGH WAS ALONG 128W WHILE THE EASTERN TROUGH WAS FROM 
10N108N TO 03N113W AND HAD SCATTERED MODERATE CONVECTION WITHIN 
270 NM E OF THE TROUGH N OF 06N. A 60-90 KT SOUTHWESTERLY UPPER 
JET IS TRANSPORTING MID TO HIGH LEVEL MOISTURE FROM THE VICINITY 
OF THIS TROUGH INTO CENTRAL MEXICO...WITH SCATTERED CIRRUS NOTED 
ALONG ITS PATH. THE STRONGEST CONVECTION ALONG THE ITCZ WAS ON 
ITS E EDGE WHERE A 1006 MB LOW PRES SYSTEM WAS NEAR 05N80W. LOW 
LEVEL CONVERGENCE IS IN PLACE BETWEEN 20 KT N TO NE WINDS IN THE 
SW CARIBBEAN AND THE 20-25 KT S TO SW WINDS NOTED BY SHIP A8IT6 
NEAR 05N88W AND A8IP4 NEAR 01N97W AS WELL AS 18 KT BY BUOY 
32303. UPPER LEVEL WINDS SHOULD REMAIN DIFFLUENT AND ALLOW FOR 
DEEP CONVECTION TO CONTINUE IN SE WATERS OVER THE NEXT TWO DAYS.
THIS IN ADDITION TO THE LOW LEVEL VORTICITY SHOULD ALLOW THE LOW 
TO SURVIVE FOR ANOTHER DAY OR SO.

$$
SCHAUER