000
AXPZ20 KNHC 212107
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED FEB 21 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 
1545 UTC.

...ITCZ...
ITCZ AXIS 3N78W 5N88W 3N100W 4N125W 3N140W. ISOLATED MODERATE 
AND STRONG CONVECTION NOTED WITHIN 15 NM OF AXIS BETWEEN 85W AND 
104W. SCATTERED MODERATE CONVECTION OBSERVED WITHIN 90 NM OF 
AXIS BETWEEN 128W AND 136W. 

...DISCUSSION...

A LONGWAVE TROUGH DOMINATES THE EASTERN N PAC WITH ITS MEAN AXIS 
S OF 35N TO A BASE DEEP IN THE TROPICS NEAR 7N135W. AN EMBEDDED 
UPPER SHORTWAVE TROUGH ENTERS THE DISCUSSION AREA NEAR 35N134W 
AND CONTINUES SW TO A BASE NEAR 30N143W. THE ASSOCIATED SURFACE 
FRONT IS CURRENTLY IN PHASE WITH THE UPPER TROUGH AND IS 
ACCOMPANIED BY A 120 NM WIDE BAND OF LOW MID LAYERED CLOUDS 
BEHIND ITS FRONTAL EDGE BUT LACKING SIGNIFICANT CONVECTION.  

A SMALL UPPER ANTICYCLONE IS NOTED NEAR 8N109W...AND IS 
SEPARATED FROM A MORE DOMINATE UPPER RIDGE THAT EXTENDS WESTWARD 
ACROSS CENTRAL AMERICA INTO THE TROPICAL E PAC ALONG 14N...ALL  
ORIGINATING FROM AN ANTICYCLONE IN THE CARIBBEAN CENTERED NEAR 
20N82W. A SMALL UPPER INVERTED TROUGH EXTENDS N ACROSS THE 
EQUATOR AT 101W TO NEAR 9N104W. 

DRY UPPER AIR IS INDICATED WITHIN ROUGHLY 180 NM EITHER SIDE OF 
LINE 32N100W 30N120W TO 22N145W. AN UPPER MOISTURE PLUME... 
ORIGINATING FROM ITCZ CONVECTION BETWEEN 126W AND 137W...LIES 
WITHIN 240 NM EITHER SIDE OF LINE FROM 12N131W TO 25N111W WHERE 
THE MOISTURE EVAPORATES. UPPER MOISTURE IS NOTED ALONG THE 
INVERTED TROPICAL UPPER TROUGH...ROUGHLY S OF 9N BETWEEN 98W AND 
105W. ELSEWHERE THE UPPER LEVELS ARE VERY DRY AND SUPPRESSING 
ITCZ CONVECTION TO ISOLATED AT BEST OVER THE WATERS E OF 105W.
  
GAP WINDS...
A BROAD AREA OF LOW PRES OVER THE SW GULF OF MEXICO IS EXPECTED 
TO SHIFT EASTWARD TONIGHT. NLY WINDS W OF THE TROUGH AXIS WILL 
BRIDGE THROUGH THE ISTHMUS OF TEHUANTEPEC INTO THE E PAC 
WATERS JUST AFTER SUNRISE THU...AND GRADUALLY INCREASE TO 20 TO 
30 KT FRI MORNING. BRISK ELY TRADES IN THE SW CARIBBEAN WILL 
CONTINUE TO BRIDGE W INTO THE GULF OF PAPAGAYO AT 20 TO 25 KT 
THROUGH FRI. MODELS SUGGEST NLY WINDS TO SURGE TO 20 KT IN THE 
GULF OF PANAMA THROUGH FRI. NW WINDS SURGING BRIEFLY TO 20 KT 
OVER SEA OF CORTEZ WATERS S OF 25N THIS MORNING ARE EXPECTED TO 
DIMINISH TO LESS THAN 20 KT THIS AFTERNOON. 

$$
NELSON