000
AXPZ20 KNHC 131004
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU MAY 13 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 07N78W TO 04N82W TO 05N93W TO 
07N104W TO 05N114W TO 07N127W TO 05N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE AXIS 
BETWEEN 119W-127W...AND 60 NM S OF THE AXIS BETWEEN 
86W-90W...AND ALSO BETWEEN 97W-101W. SIMILAR CONVECTION IS 
WITHIN 60 NM N OF THE AXIS BETWEEN 130W-132W.

...DISCUSSION...

A DEEP LEVEL TROUGH EXTENDS FROM THE WESTERN US.S SW TO 25N128W
TO 22N134W WHERE IT BECOMES A SHEAR AXIS TO W OF THE AREA AT
21N140W. MODERATE TO STRONG SUBSIDENCE LEADING TO DRY STABLE
CONDITIONS IS NOTED WITHIN ABOUT 400 NM SE AND S OF THE TROUGH
...WHILE UPPER LEVEL MOISTURE IS SURGING S INTO THE AREA BEHIND 
THE TROUGH. THE TROUGH IS FORECAST TO MOVE INLAND THE U.S. W 
COAST TONIGHT. A MID/UPPER LEVEL TROUGH JUST MOVING INLAND BAJA
CALIFORNIA AND THE NW PORTION OF MEXICO. 

TO THE S OF THE TROUGH...A BROAD UPPER LEVEL ANTICYCLONE IS  
CENTERED NEAR 7N120W WITH A RIDGE AXIS EXTENDING SE TO NEAR 
5N88W. ANOTHER RIDGE EXTENDS FROM THE ANTICYCLONE TO W OF THE
AREA NEAR 7N142W. CONVECTION IS BEING ENHANCED ALONG AND S OF 
THE RIDGE UNDER UPPER DIFFLUENCE ALONG THE ITCZ MAINLY W OF 
113W. A JET STREAM BRANCH ENTERS THE REGION THROUGH 17N140W
...AND CONTINUES TO 21N130W THEN E TO 21N117W THEN ROUNDS THE
BASE OF THE ABOVE TROUGH AS IT PRESSES INLAND MEXICO OVER CABO 
CORRIENTES. THE JET THEN SHARPLY TURNS NE TO ACROSS THE 
CENTRAL U.S. SATELLITE WINDS SHOWS MAXIMUM JET CORE WINDS OF 
60-150 KT ALONG THE CENTER SEGMENT OF THE JET. THESE WINDS ARE
PUMPING PLENTIFUL UPPER LEVEL MOISTURE IN THE FORM OF BROKEN
CIRRUS CLOUDS FROM THE TROPICAL CENTRAL PACIFIC REGION NE AND E 
ACROSS THE DISCUSSION AREA...WITH A TRAJECTORY TOWARDS CENTRAL
MEXICO. 

A WEAK UPPER LEVEL TROUGH EXTENDS FROM BELIZE TO ACROSS 
GUATEMALA TO NEAR 11N92W. IN ITS WAKE...STRONG SUBSIDENCE WITH
VERY DRY AIR IS EVIDENT N OF 8N AND W TO 98W. SIMILAR DRY AIR 
WAS AHEAD OF THE TROUGH. OVER THE EASTERN SECTION OF THE AREA
...AN UPPER LEVEL RIDGE EXTENDS ALONG 4N/5N TO THE E OF 88W...
AND TO INLAND S AMERICA. UPPER LEVEL DIFFLUENCE UNDER THIS RIDGE 
IS ENHANCING ITCZ CONVECTION BETWEEN 86W-90W.

AT THE SURFACE...A HIGH CENTER N OF THE AREA NEAR 34N139W 1031 MB
EXTENDS A RIDGE SE TO 25N126W TO 18N115W. HIGH PRES COVERS THE 
ARA N OF 15N AND W OF 115W. PRES GRADIENT BETWEEN THE RIDGE AND
LOWER PRES TO THE S DUE TO THE ITCZ ARE RESULTING IN NE TRADES OF
20-25 KT FROM 9N-27N BETWEEN 120W-130W...AND FROM 9N-28N W OF 
130W. NW-N WINDS OF 20-25 KT ARE OCCURRING NE OF THE RIDGE AXIS 
N OF 27N GENERALLY BETWEEN 118W-127W. SEAS IN THE RANGE OF 8-12 
FT DUE TO MIXED NE AND S SWELL CAN BE FOUND WITHIN THE AREA OF 
TRADES WITH THE HIGHEST OF THE SEAS IN THE SW PORTION.

1008 MB LOW PRES IS CENTERED NEAR 4N82W. CONVECTION NOTED EARLIER
HAS SINCE DIMINISHED...BUT IS EXPECTED TO REFORM LATER TODAY. THE
IS FORECAST TO WEAKEN INTO A POSSIBLE TROUGH DURING THE NEXT
24 HOURS.

GAP WINDS...NE TO E WINDS AT 20 TO 25 KT ARE SURGING THROUGH
THE GULF OF PAPAGAYO AND DOWNWIND TO NEAR 10N90W. THIS SURGE
IS EXPECTED TO GRADUALLY DIMINISH TO LESS THAN 20 KT BY 48 HOURS.

$$
AGUIRRE