Subject: Pacific-EN: Tropical Weather Discussion

From: SIU Weather Processor <[email-masked]>
Date: Mon, 21 Feb 2005 15:54:10 -0600

AXPZ20 KNHC 212153
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON FEB 21 2005

TROPICAL WEATHER DISCUSSION FOR EASTERN PACIFIC OCEAN FROM 
EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

..ITCZ...
ITCZ AXIS IS ALONG 5N77W 6N105W 7N140W. WIDELY SCATTERED 
MODERATE DEVELOPING WITHIN 30 NM OF AXIS BETWEEN 87W AND 91W.

DISCUSSION...
A 900 NM WIDE WESTERLY JETSTREAM IS CENTERED ALONG A LINE TROUGH 
15N140W TO 14N120W WHERE THE FLOW SPLITS WITH ONE BRANCH 
CONTINUING CYCLONICALLY NE TO BEYOND 24N100W. THE SECOND TURNS 
ANTICYCLONICALLY SE AND LOSES IDENTITY IS STRONG DRY UPPER AIR. 
ADDITIONALLY DRY AIR IS INDICATED S OF THE JET.

N OF THE JET A MID TO UPPER LEVEL TROUGH IS BECOMING NEGATIVE 
TILT WITH TIME...BUT ITS MEAN AXIS IS CURRENTLY ALONG 32N123W 
20N118W. THE ASSOCIATED CYCLONE IS LOCATED JUST N OF THE 
DISCUSSION AREA NEAR 36N125W. AT THE SURFACE A COLD FRONT LIES 
ALONG 32N118W 25N119W 19N133W. 

THE UPPER LEVELS N OF THE JET AXIS ARE DRY INDICATING MODERATE 
TO STRONG UPPER LEVEL SUBSIDENCE. AN EXCEPTION IS N OF 27N ALONG 
THE COLD FRONT WHERE A FEW SHOWERS ARE ENHANCED WITH THE DEBRIS 
MOISTURE ADVECTED NE ACROSS THE NORTHERN BAJA PENINSULA.
A BAND OF UPPER MOISTURE IS OBSERVED WITHIN THE UPPER WIND 
MAXIMA...WITH AXIS 11N140W 16N120W 27N90W. 

A SMALL UPPER CYCLONE IS OBSERVED NEAR 3N81W AND ANOTHER NEAR 
12N88W. PRONOUNCED DRY CONDITIONS ALOFT NOTED SE OF LINE 10N114W 
26N81W EXCEPT FOR THE SMALL AREA OF CONVECTION ASSOCIATED WITH 
THE ITCZ.  UPPER LEVEL MOISTURE EMANATING FROM THIS CONVECTION 
IS ADVECTING NE TO OVER WESTERN PANAMA COSTA RICA AND 
NICARAGUA...HOWEVER NO CLOUDINESS IS PRESENT AT THIS TIME.

NE WINDS ARE SPREADING W ACROSS CENTRAL AMERICA INTO THE PAC 
FROM 9N TO 12N E OF 92W. SIMILAR CONDITIONS ARE EXPECTED IN THE 
GULF OF PANAMA.  

$$
NELSON

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