000
AXPZ20 KNHC 211620
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN JAN 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 
1600 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 3N78W 5N90W 5N100W 5N110W 5N120W
6N130W 6N140W. NO SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

A SHORTWAVE TROUGH HAS MOVED INTO THE NE PORTION OF THE REGION
AND IS QUICKLY PUSHING SEWD FROM THE SW UNITED STATES SWWD ACROSS
NRN BAJA CALIFORNIA AND SW TO 26N120W TO 27N132W. A SMALL 
MID/UPPER LEVEL CYCLONIC CIRCULATION ALSO DROPPING RAPIDLY SWD 
IS NEAR 26.5N120W. CONFLUENT UPPER LEVEL FLOW INTO THE TROUGH IS 
RESULTING IN MODERATE SUBSIDENCE AND ASSOCIATED DRY AIR N OF 18N 
E OF 137W. UPPER LEVEL RIDGING IS ALONG THE NW CORNER OF THE 
REGION FROM 28N140W NE TO WELL N OF THE AREA WITH A CREST AT 
35N138W. THE ELY TRADES REMAIN IN THE MODERATE TO STRONG RANGE 
WITH MAXIMUM RANGE REACHING UP TO 30 KT W OF 137W. DESPITE THE 
FACT THAT THERE IS SOME LOW-LEVEL CONVERGENCE AND SUFFICIENT 
MOISTURE ALONG THE ITCZ...THE FLOW ALOFT W OF 110W IS PRIMARILY 
ZONAL SO THERE ARE VERY LITTLE DYNAMICS AVAILABLE TO ENHANCE 
CONVECTION THERE. A WEAK MID/UPPER LEVEL TROUGH IS JUST ENTERING 
THE REGION THROUGH 23N139W 15N139W. STRONG SUBSIDENCE AS SEEN IN 
WATER VAPOR IMAGERY EXISTS FROM 12N-20 N W OF 129W FURTHER 
SUPPRESSING CONVECTION FROM DEVELOPING W OF 130W. AT THE 
SURFACE...A RIDGE AXIS EXTENDS FROM 32N129W THROUGH 25N122.5W TO 
21.5N109W. HIGH PRES COVERS THE AREA N OF 12N W OF 108W. A SURGE 
OF STRONG NLY WINDS IS EVIDENT N OF 23N E OF 134W...AND IS 
MARKED BY CLEAR SKIES.

FARTHER E...MID AND UPPER LEVEL RIDGING REMAINS IN CONTROL HERE 
WITH MODERATE TO SUBSIDENCE AND ASSOCIATED DRY AIR AS SEEN ON 
WATER VAPOR IMAGERY. SO CONVECTION ALONG AND NEAR THE ITCZ EXISTS
ONLY AS ISOLATED WEAK SHOWERS AND TSTMS. A WEAK UPPER LEVEL SHEAR
AXIS EXTENDS FROM 13N101W S TO 6N101W...BUT IT WELL ENTRENCHED 
IN THE SUBSIDENCE AREA PROHIBITING IT FROM FIRING UP ANY 
CONVECTION NEAR IT. WINDS OVER THE GULF OF PANAMA WILL DIMINISH 
THROUGH THE 48 HRS AND CONTINUE NE 20 KT ACROSS THE GULF OF
PAPAGAYO.

$$
AGUIRRE