000
AXPZ20 KNHC 272118
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAR 27 2009

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 08N82W 04N88W 02N110W 06N140W. 
SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS 
BETWEEN 85W AND 91W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS WITHIN 180 NM OF THE AXIS W OF 127W.

...DISCUSSION...

W OF 120W...
THE MID TO UPPER PATTERN IS QUITE AMPLIFIED OVER THIS PORTION OF 
THE EPAC. AN UPPER LOW IS CENTERED SEVERAL HUNDRED NM NE OF 
HAWAII NEAR 24N144W DRIFTING W. UPPER DIFFLUENCE BETWEEN THE LOW 
AND A RIDGE TO ITS E IS PRODUCING SCATTERED SHOWERS AND POSSIBLE 
TSTMS FROM 18N-28N W OF 118W. A SHORTWAVE UPPER TROUGH ALONG 
125W IS ENHANCING SCATTERED CONVECTION WITHIN THE ITCZ W OF 
127W. N TO NE WINDS ARE MAINLY 15-20 KT ACROSS MUCH OF THE 
REGION N OF THE ITCZ. OVERALL LITTLE CHANGE IN WINDS ARE 
FORECAST OVER THE NEXT COUPLE OF DAYS AS THE HIGH PRES RIDGE 
REMAINS IN PLACE NW OF THE AREA. A 14-16 SECOND NW SWELL TRAIN 
HAS JUST ENTERED THE FAR NW PORTION AND WILL SPREAD ACROSS MUCH 
OF THE AREA THIS WEEKEND. 

E OF 120W...
WIDESPREAD SUBSIDENCE IS BEING ENHANCED BY CONFLUENCE ALOFT 
BETWEEN AN UPPER HIGH NEAR 3N91W AND LARGE SCALE TROUGHING OVER 
MEXICO. SFC WINDS ARE FAIRLY LIGHT EXCEPT FOR THE GULF OF 
CALIFORNIA WHERE A RECENT HI-RES QSCAT PASS REVEALED THE 
EXPECTED 20-25 KT N FLOW. THESE WINDS ARE ONLY FORECAST TO 
PERSIST FOR 24-36 HOURS. BEYOND THAT...THE GREAT BASIN HIGH 
BREAKS DOWN AND IS REPLACED BY LOW PRES OVER THE AREA. THIS WILL 
ALLOW WINDS TO BECOME LIGHT AND VARIABLE IN THE REGION. OTHER 
FORECAST CONCERN IS THE GULF OF TEHUANTEPEC. WHILE MUCH OF THE 
NWP MODEL GUIDANCE SHOWS A COLD FRONT STAYING JUST N OF THE 
TEHUANTEPEC... IT APPEARS VERY CLOSE TO THE REGION AND MODELS 
TYPICALLY HAVE DIFFICULTY IN SHOWING CORRECT FRONTAL STRUCTURE 
DUE TO TOPOGRAPHIC INFLUENCES. SO...ADDED MENTION OF 20-25 KT N 
FLOW IN THE GAP AS THE FUNNELING COULD OCCUR IF THE FRONT 
CROSSES.  

$$
CANGIALOSI