000
AXPZ20 KNHC 152126
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAY 15 2010

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 
2100 UTC.

...TROPICAL WAVES...

A WEAK TROPICAL WAVE IS ALONG 94W FROM 04N-10N MOVING W AT 10 
KT. NO SIGNIFICANT CONVECTION WAS NOTED DUE TO INCREASING N-NE 
WIND SHEAR. THE WAVE IS NOT EXPECTED TO DEVELOP ANY CYCLONIC 
ORGANIZATION WITHIN NEXT 48 HOURS.

...ITCZ...

ITCZ AXIS IS ALONG 07N78W TO 07N93W TO 09N103W TO 09N115W TO 
08N134W TO 08N140W. SCATTERED MODERATE CONVECTION IS WITHIN 240 
NM S OF THE AXIS BETWEEN 82W AND 90W...AND ALSO WITHIN 60 NM S 
OF THE AXIS BETWEEN 118W AND 124W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM 32N111W TO 21N117W TO 
19N140W. VERY DRY AIR IS IN PLACE N OF THIS TROUGH AXIS TO 30N. 
ANOTHER UPPER LEVEL TROUGH IS TO THE W EXTENDING FROM 32N135W TO 
26N140W WITH MID TO UPPER LEVEL MOISTURE ARRIVING BEHIND THE 
TROUGH AXIS. 

AN UPPER ANTICYCLONE IS CENTERED NEAR 10N104W WITH A RIDGE AXIS 
EXTENDING ALONG 10N ACROSS THE ENTIRE BASIN. A JETSTREAM WITH 
CORE WIND SPEEDS OF 75-95 KT ENTERS THE AREA NEAR 17N140W AND 
EXTENDS TO THE NE-E INTO CENTRAL MEXICO NEAR 21N105W. MID TO 
UPPER LEVEL MOISTURE IS BEING ADVECTED FROM THE DEEP TROPICS S 
OF THE HAWAIIAN ISLANDS TO THE NE-E AROUND THE NORTHERN 
PERIPHERY OF THE ANTICYCLONE AND RIDGE. MODERATE UPPER LEVEL 
DIFFLUENCE ON THE S SIDE OF THE ANTICYCLONE IS HELPING TO 
ENHANCE SPORADIC CONVECTION ALONG THE ITCZ...ESPECIALLY E OF 90W.

A 1011 MB SURFACE LOW IS CENTERED NEAR 09N104W ALMOST DIRECTLY 
UNDER THE AFOREMENTIONED UPPER ANTICYCLONE. ALTHOUGH CURRENTLY 
SCATTERED MODERATE CONVECTION IS ONLY CONFINED TO BETWEEN 120 NM 
TO 240 NM OF THE LOW CENTER IN THE SW QUADRANT...MODEL GUIDANCE 
AGREES ON A SLOW WESTWARD DRIFT ALONG 09-10N DURING THE NEXT 48 
HOURS WHILE KEEPING IT UNDERNEATH THE UPPER RIDGE WHICH MAY 
ALLOW FOR THE ENHANCEMENT OF CONVECTION AND A CHANCE OF SOME 
ADDITIONAL DEVELOPMENT.

ELSEWHERE AT THE SURFACE...1025 MB HIGH PRES IS CENTERED NEAR 
30N137W WITH A BROAD RIDGE AXIS EXTENDING FROM THE HIGH CENTER 
TO NEAR 16N113W. NE TRADES AT 20-25 KT ARE SW OF THE RIDGE AXIS 
FROM 10N TO 21N W OF 126W. THE STRENGTH AND AREAL COVERAGE OF 
THESE TRADES WILL DIMINISH SIGNIFICANTLY DURING THE NEXT 48 
HOURS AS THE PRES GRADIENT WEAKENS. NE SWELL GENERATED FROM THE 
TRADES IS MIXED WITH CROSS EQUATORIAL SW SWELL. THIS SW SWELL 
COVERS THE MAJORITY OF THE REMAINDER OF THE DISCUSSION AREA AND 
WILL GRADUALLY DECAY AND SUBSIDE TO LESS THAN 8 FT DURING THE 
NEXT 48 HOURS.

GAP WINDS...FRESH NE-E WINDS THROUGH THE GULF OF PAPAGAYO E OF 
90W ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT IN 18 HOURS AS 
THE SOURCE OF THE STRONG WINDS IN WESTERN CARIBBEAN WEAKENS. A
1550Z WINDSAT PASS CAPTURED NE WINDS OF 20-25 KT IN THE GULF OF 
FONSECA DOWNWIND TO 12N90W ALTHOUGH THESE WINDS ARE EXPECTED TO 
DIMINISH TO LESS THAN 20 KT WITHIN THE NEXT 6 HOURS.

NOTE...TODAY MARKS BEGINNING OF 2010 EASTERN NORTH PACIFIC 
HURRICANE SEASON WHICH RUNS THROUGH NOVEMBER 30. ON AVERAGE... 
SIXTEEN TROPICAL STORMS FORM EVERY YEAR...NINE OF WHICH WILL 
BECOME HURRICANES WITH FOUR REACHING MAJOR STATUS. THE FIRST 
TROPICAL STORM THIS SEASON WILL BE NAMED AGATHA.

$$
LEWITSKY