000
AXPZ20 KNHC 261527
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON APR 26 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED ALONG 09N84W TO 
08N87W TO 07N89W TO 08N121W TO 04N140W. SCATTERED MODERATE 
CONVECTION IS FROM 04N TO 07N BETWEEN 79W AND 83W. SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 240 NM OF THE 
AXIS BETWEEN 89W AND 101W. ISOLATED MODERATE CONVECTION IS 
WITHIN 120 NM OF THE AXIS BETWEEN 115W AND 122W AND BETWEEN 130W 
AND 140W.

...DISCUSSION...
A RIDGE AXIS EXTENDS SW TO NEAR 16N110W FROM A 1022 MB HIGH 
CENTERED NEAR 25N144W. THIS HIGH PRESSURE SYSTEM CONTINUES TO 
WEAKEN AS AN UPPER LEVEL TROUGH SLICES THE NW CORNER OF THE 
DISCUSSION AREA FROM 30N123W TO 20N140W WITH A WEAK COLD FRONT 
POISED TO BEGIN IMPACTING THE NORTHWESTERN WATERS BY EARLY 
TUESDAY. AS THE FRONT SKIRTS THE NORTHERN WATERS AND DISSIPATES 
BY WEDNESDAY...THE REMAINS OF THE HIGH ARE FORECAST TO MERGE 
WITH STRONGER HIGH PRESSURE TO THE W. AN EARLIER MORNING ASCAT 
PASS AROUND 26/0630 UTC INDICATES THE AREA OF FRESH TRADES 
CONTINUES TO ENVELOPE A SMALL AREA FROM ROUGHLY 08N TO 15N W OF 
125W AND IS EXPECTED TO SHRINK THROUGH THE FORECAST PERIOD. 
MEANWHILE...A 90-130 KT SOUTHWESTERLY UPPER LEVEL JET IS ON THE 
LEADING EDGE OF THE TROUGH REMAINING MAINLY N OF 17N OVER THE N 
WATERS. THIS JET IS TRANSPORTING UPPER LEVEL MOISTURE MANIFESTED 
AS CIRRUS NORTHEASTWARD FROM THE ITCZ W OF 115W. FINALLY...WITH 
THE COLD FRONT EXPECTED BY EARLY TUESDAY...THE PRIMARY IMPACT 
WILL BE A SURGE IN NW SWELL WITH SIGNIFICANT WAVE HEIGHTS RISING 
TO 9 FT W OF THE FRONT TUESDAY AFTERNOON.

ALOFT...THE REMAINDER OF THE DISCUSSION AREA IS UNDER THE 
INFLUENCE OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED 
NEAR 13N105W THAT IS EXPECTED TO SLOWLY SLIDE EASTWARD AS THE 
AFOREMENTIONED UPPER LEVEL TROUGH TO THE NW MOVES THROUGH THE 
NORTHERN WATERS. IN THE MEANTIME...AREAS OF ISOLATED MODERATE 
CONVECTION ARE NOTED ALONG THE ITCZ BETWEEN 105W AND 140W.

A BROAD LOW LEVEL CYCLONIC GYRE LIES OVER THE SE WATERS. WHILE A 
WEAK SURFACE TROUGH IS ANALYZED FROM 02N88W TO 10N87W...GLOBAL 
MODELS ARE BEGINNING TO KEY ON ANOTHER AREA OF MIDDLE TO LOW 
LEVEL CYCLONIC FLOW CURRENTLY LOCATED OVER THE SW CARIBBEAN 
MOVING WESTWARD. THE ENERGY ASSOCIATED WITH THESE GYRES ARE 
FORECAST TO MERGE OVER THE SE WATERS AND BRING POTENTIALLY HEAVY 
RAINFALL ACROSS PORTIONS OF SOUTHERN CENTRAL AMERICA THE NEXT 
SEVERAL DAYS. TOTAL PRECIPITABLE WATER IMAGERY AND GFS MODEL 
FORECAST SOUNDINGS INDICATE VALUES OF PRECIPITABLE WATER AT OR 
ABOVE 2.4 INCHES OVER MUCH OF THE AREA E OF 95W...WHICH WILL 
ALLOW FOR PLENTY OF LOW LEVEL MOISTURE TO CONVERGE ALONG AND 
NORTH OF THE ITCZ. STRONG CONVECTION WILL LIKELY BE ENHANCED E 
OF 90W AS CONDITIONS ALOFT ARE FORECAST TO REMAIN WITHIN A 
FAIRLY DIFFLUENT PATTERN. A PORTION OF THE UPPER LEVEL 
ANTICYCLONE CENTERED NEAR 13N105W WILL DRIFT EASTWARD ACROSS 
SOUTHERN MEXICO AND LOCATE ITSELF OVER THE WESTERN CARIBBEAN AND 
CENTRAL AMERICA BY EARLY TUESDAY.

FINALLY...LARGE LONG PERIOD NW SWELLS WILL CONTINUE TO PROPAGATE 
THROUGH THE BASIN AND MERGE WITH CROSS-EQUATORIAL SW SWELL 
ACROSS THE TROPICS THROUGH WEDNESDAY.

$$
HUFFMAN