000
AXPZ20 KNHC 012205
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAY 01 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 
2145 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N78W 4N98W 3N111W 4N120W 3N130W 
4N140W. ISOLATED MODERATE CONVECTION IS S OF THE AXIS WITHIN
45 NM OF 4N93W...AND WITHIN 30 NM OF 5N86W AND 5N89W.

...DISCUSSION...

HIGHLY AMPLIFIED FEATURES AREA ACROSS THE DISCUSSION AREA. THE 
FIRST BEING BROAD MID AND UPPER RIDGING STRETCHING FROM FROM 
NW MEXICO TO THE CENTRAL PORTION OF THE AREA WITH A MEAN AXIS
GENERALLY ALONG 32N107W SW TO ACROSS SRN BAJA TO 19N116W TO
A WELL ANCHORED ANTICYCLONE NEAR 10N120W. A WEAK LOW TO MID 
LEVEL INVERTED TROUGH EXTENDS FROM 8N134W TO 2N131W. UPPER LEVEL 
DIFFLUENCE BETWEEN THE TROUGH AND THE ANTICYCLONE MAY ALLOW
FOR CONVECTION TO INCREASE ALONG OR NEAR THE ITCZ BETWEEN 
132W-135W. THE TROUGH IS EXPECTED TO LOSE ITS IDENTITY OVER THE 
NEXT 24 HRS AS THE DEEP LAYER TROUGH DESCRIBED BELOW TAKES 
PRECEDENCE.

A NEARLY STATIONARY MID/UPPER LEVEL TROUGH IS OVER THE FAR ERN 
PORTION OF THE AREA EXTENDING FROM SE MEXICO SW TO 10N103W TO
1N108W. A SMALL UPPER LEVEL CYCLONIC CIRCULATION MOVING W IS
EMBEDDED IN THE TROUGH ALONG THE COAST OF MEXICO NEAR 16N98W.
BROKEN MID AND UPPER LEVEL CLOUDS ARE BEING CHANNELED NEWD 
ACROSS CENTRAL AMERICA DRIVEN BY A JET STREAM FROND TO THE 
E OF THE TROUGH ALONG 7N105W TO 11N98W NE TO ACROSS SE MEXICO
AND WRN GUATEMALA. SCATTERED SHOWERS AND TSTMS OVER CENTRAL 
AMERICA AND WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE N OF
THE ITCZ BETWEEN 90W-97W WITH AN INCREASE IN SCATTERED TSTMS
OVER E MEXICO BETWEEN 91W-97W...AND OVER GUATEMALA AND HONDURAS.
THIS CONVECTIVE ACTIVITY IS FORECAST TO WILL CONTINUE THROUGH AT 
LEAST THE NEXT COUPLE OF DAYS AS THE LOW AND TROUGH REMAIN ABOUT 
STATIONARY.

MEANWHILE...THE RIDGE WILL GET NUDGED TO E OF THE AREA THROUGH
SAT BY A RATHER SHARP DEEP LAYER TROUGH PRESENTLY ALONG 32N125W
TO 25N127W TO 18N134W TO 12.5N140W. A VERY WELL PRONOUNCED NRN 
STREAM JET STREAM BRANCH WITH MAXIMUM WINDS OF 70-130 KT SHARPLY 
DIVES SEWD BRUSHING THE FAR NRN BOUNDARY OF THE AREA. THE TROUGH
WILL QUICKLY LIFT NE AND SHEAR OUT OVER THE FAR NE PART OF
THE AREA AND ACROSS NRN BAJA CALIFORNIA AND SRN CALIFORNIA ON
SAT. 

AT THE PRESENT TIME...DEEP LAYER MOISTURE CONSISTING OF BROKEN 
MULTILAYERED CLOUDS WITH SCATTERED SHOWERS AND ISOLATED TSTMS IS 
ADVECTING NEWD ACROSS THE CENTRAL AND NE PORTIONS OF THE AREA
WITHIN 160 NM E OF THE TROUGH.

BROAD/MID UPPER LEVEL RIDGING COVERING THE WRN CARIBBEAN SEA 
ALSO EXTENDS W ACROSS CENTRAL AMERICA TO THE E OF THE MID/UPPER 
LEVEL TROUGH OVER THE ERN PORTION OF THE AREA.

AT THE SURFACE...HIGH PRES OF 1021 MB IS NEAR 25.5N127W WITH A 
RIDGE SE TO 24N118W TO 18N110W. AS THE TROUGH W OF THE AREA 
ADVANCES EWD THROUGH THE NEXT 48 HRS...THE RIDGE WILL ALSO SLIDE 
E WHILE LOW PRES DEEPENS OVER THE PLAINS INTO NRN MEXICO. THIS 
WILL ALLOW FOR THE PRES GRADIENT TO INCREASE OVER THE NE PART OF 
THE AREA INCREASING NW WINDS ALONG THE BAJA CALIFORNIA COAST TO 
THE RANGE OF 20-25 KT IN 24 HRS...THEN DIMINISHING SLIGHTLY IN 
48 HRS AND INCREASING ONCE AGAIN AFTER THAT.

S-SW WINDS OF 20-25 KT ARE OVER THE NW PART OF THE AREA.

A WEAK TROUGH MOVING WNW 15 KT EXTENDS FROM 4N132W TO 10N131W.
THIS FEATURE ALONG WITH THE WEAK LOW AND MID LEVEL TROUGH TO ITS 
W HAD EARLIER INCREASED ITCZ CONVECTION...BUT THE CONVECTION
HAS RECENTLY WEAKENED.

$$
AGUIRRE