000
AXPZ20 KNHC 110923
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAY 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS ALONG 8N77W 7N100W 10N117W 
6N130W 5N140W. ISOLATED STRONG CONVECTION NEAR 8N82W 7N101W 
6N103W AND 10N110W. SCATTERED MODERATE WITHIN 45 NM OF A LINE 
FROM 9N91W TO 7N100W AND FROM 7N103W TO 7N108W. ISOLATED STRONG 
CONVECTION NEAR 11N115W AND 6N128W. SCATTERED MODERATE WITHIN 60 
NM OF A LINE FROM 6N103W TO 10N111W AND NEAR 5N130W. 

...DISCUSSION...

A LARGE MID LEVEL TROUGH REMAINS OVER THE REGION TONIGHT N OF 
20N W OF 120W. ONE SHORTWAVE JUST N OF THE AREA ALONG 135W IS 
LIFTING NE WHILE A NEW SHORTWAVE IS SEEN IN WATER VAPOR IMAGERY 
NW OF THE REGION MOVING SE. MOVEMENT OF THIS SECOND SHORTWAVE 
WILL MAINTAIN A POLAR JET SEGMENT WHICH HAS PUSHED INTO THE 
EXTREME NW CORNER OF OUR REGION TONIGHT. THE JET IS SEEN AS A 
SHARP EDGE IN THE WATER VAPOR FROM 31N136W TO 27N143W. OTHERWISE 
A FLAT MID LEVEL RIDGE COVERS THE AREA E OF 130W. THE RIDGE IS 
BULGING NWD ALONG 110W ACTING AS A BLOCK TO A WEAK SHORTWAVE 
THAT IS OVER THE SRN CA COAST. ON THE SURFACE TONIGHT THE 
PACIFIC RIDGE REMAINS FAIRLY WEAK. NE TRADES ARE STRONGEST 
BETWEEN 10N AND 20N W OF 125W WITH SPEEDS OF 15 TO 20 
KT..OTHERWISE WINDS OVER THE REGION N OF 10N W OF 110W ARE 
MOSTLY LIGHT N AND NE ACCORDING TO SSMI AND QUIKSCAT. GAP WINDS 
ALONG THE CENTRAL AMERICAN COAST ALSO REMAIN LIGHT. CONVECTION 
ALONG THE ITCZ IS FAIRLY ACTIVE TONIGHT BETWEEN 98W AND 130W. A 
FLARE UP BETWEEN 112W AND 118W IS BEING AIDED BY ANTICYCLONIC 
FLOW ALOFT.

LATER DAY 1 LITTLE CHANGE TO THE OVERALL MID LEVEL PATTERN. 
WHILE STRONGER SHORTWAVES REMAIN JUST N OF THE REGION AS THEY 
CURVE THROUGH THE MAIN TROUGH..WEAKER IMPULSES IN THE SRN BRANCH 
OF THE WESTERLIES CONTINUE TO WORK THEIR WAY FROM THE S CENTRAL 
PACIFIC. SOME WILL BE NEAR 18N140W..ANOTHER NEAR 20N130W AND A 
THIRD NEAR 25N123W. ON THE SURFACE LATER DAY 1 THE PACIFIC RIDGE 
WILL REMAIN WEAK WITH NE TRADES MOSTLY 10 TO 15 KT. A SURFACE 
RIDGE UNDERNEATH A BROAD MID LEVEL TROUGH JUST DOESN'T GET THE 
SUPPORT IT NEEDS. REMAINDER OF THE REGION SHOULD HAVE MOSTLY 
LIGHT WINDS.

FOR DAY 2 MID LEVEL HEIGHTS BEGIN TO SLOWLY INCREASE W OF 130W 
AS THE MID LEVEL TROUGH WEAKENS AND THE FLOW BECOMES MORE WLY. A 
MODERATE SHORTWAVE MOVING THROUGH THE TROUGH MOVES TO 127W JUS N 
OF THE REGION. WEAK IMPULSES IN THE SRN BRANCH CONTINUE WITH ONE 
NEAR 30N114W..ANOTHER NEAR 23N132W AND A THIRD APPROACHING THE 
REGION ALONG 30N145W. LITTLE CHANGE TO THE FLAT MID LEVEL RIDGE 
THAT COVERS THE REMAINDER OF THE REGION. THE RIDGE CONTINUES TO 
BULGE NWD ALONG 109W BLOCKED BY A LARGE MID LEVEL TROUGH ALONG 
90W. ON THE SURFACE DAY 2 THE PACIFIC RIDGE BEGINS TO TAKE ON 
IT'S FAMILIAR APPEARANCE AND NE TRADES INCREASE SLIGHTLY TO 15 
TO 20 KT. WINDS ALONG THE BAJA COAST ALSO PICK UP SOME TO 15 TO 
20 KT. OTHERWISE LITTLE CHANGE ELSEWHERE. 

$$
RRG