000
AXPZ20 KNHC 071527
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JUN 07 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM 11N99W TO 08N118W WHERE IT 
TRANSITIONS TO THE ITCZ TO 09N128W TO 1010 MB LOW PRES NEAR 
08N131W TO BEYOND 07N140W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS FROM 06N TO 10N BETWEEN 96W AND 108W. SIMILAR 
CONVECTION IS ALSO NOTED ELSEWHERE FROM 07N TO 11N BETWEEN 120W 
AND 130W. 

...DISCUSSION...

ALOFT...A NARROW UPPER TROUGH STRETCHES FROM THE SW U.S. SW TO 
ACROSS NRN BAJA CALIFORNIA TO A DEVELOPING LOW AT 22N132W AND S 
TO 17N135W. FLATTENING MID/UPPER RIDGE IS TO THE S AND E OF 
THROUGH MAINLY FROM 13N-23N. AN ANTICYCLONIC CIRCULATION IS 
CENTERED NEAR 31N138W. BROAD UPPER LEVEL RIDGING COVERS THE ERN 
PORTION OF THE FORECAST AREA. SATELLITE WATER VAPOR IMAGERY 
SHOWS MODERATE TO STRONG SUBSIDENCE ALLOWING FOR RATHER DRY AND 
STABLE ATMOSPHERIC CONDITIONS TO BE PRESENT ACROSS THE MAJORITY 
OF THE REGION BETWEEN 13N AND 26N AND ALSO N OF 26N E OF 120W. 
THE DEVELOPING UPPER LOW AT 22N132W IS FORECAST TO SHIFT SW AND 
DEEPEN THROUGH SAT...ALLOWING FOR MID TO UPPER LEVEL RIDGING TO 
REBUILD PARTICULARLY N OF 12N E OF 130W. THE ANTICYCLONE AT 
31N138W WILL MOVE E TO NEAR 124W BY LATE FRI NIGHT BEFORE IT 
BECOMES DIFFUSE AS THE SRN PART OF BROAD TROUGH PASSES ALONG 
32N/33N.

DEEP ATMOSPHERIC MOISTURE REMAINS IN THE TROPICS ALONG AND NEAR 
THE MONSOON TROUGH AND ITCZ WITH ASSOCIATED CONVECTIVE ACTIVITY 
AS DESCRIBED ABOVE. A DIFFLUENT PATTERN ALOFT IS HELPING TO 
INDUCE THIS SHOWER/TSTM ACTIVITY. 

A WEAK SURFACE TROUGH EXTENDS FROM 14N94W TO 06N95W. SCATTERED 
SHOWERS AND TSTMS ARE NEAR THE NORTHERN END OF THE TROUGH AXIS 
AFFECTING THE GULF OF TEHUANTEPEC. 

A 1027 MB HIGH CENTER IS JUST NW OF THE AREA AT 32N143W WITH A 
RIDGE EXTENDING SE TO NEAR 20N115W. HIGH PRES COVERS THE AREA N 
OF 15N AND W OF 115W. PRES GRADIENT BETWEEN THE RIDGE AND A 
SURFACE TROUGH ALONG THE GULF OF CALIFORNIA IS SUPPORTING AN 
AREA OF NW TO N WINDS OF 20 TO 25 KT MAINLY N OF 24N E OF 127W. 
ON THE SOUTHERN PERIPHERY OF THE RIDGE...AN AREA OF 20 KT TRADE 
WINDS CAN BE FOUND PARTICULARLY FROM 10N TO 20N W OF 128W. THIS 
WEATHER PATTERN WILL PERSIST OVER THE NEXT TWO DAYS AS HIGH PRES 
MOVES MAINLY N AND SLIGHTLY STRENGTHENS  

AS PREVIOUSLY MENTIONED...A 1010 MB ILL-DEFINED LOW PRES REMAINS 
EMBEDDED WITHIN THE ITCZ...AND IS CENTERED NEAR 08N131W BASED ON 
SATELLITE IMAGERY AND AN EARLIER ASCAT PASS. THE LOW IS MOVING W 
AT NEAR 10 KT. THE ASCAT PASS REVEALED NE 20 KT WITHIN 120 NM OF 
THE LOW IN THE NW QUADRANT...AND WITHIN ABOUT 60 NM OF THE LOW 
IN THE SE QUADRANT. THE ASSOCIATED CONVECTIVE ACTIVITY IS MAINLY 
TO THE E OF THE CENTER DUE TO UPPER WLY WINDS THAT CONTINUE TO 
INHIBIT ANY DEVELOPMENT. WITH THE PRESENCE OF AN UPPER LEVEL LOW 
TO ITS NW...EXPECT ITS ASSOCIATED CONVECTION TO POSSIBLY 
INCREASE OVER THE THE NEXT 24-48 HRS. THE LOW WILL CONTINUE IN A 
GENERAL WWD TRACK OVER PROGRESSIVELY COOLER SEA SURFACE 
TEMPERATURES THROUGH EARLY SAT MORNING WHERE IT IS FORECAST TO 
REACH 135W. EXPECT NE WINDS OF 20 KT AND SEAS TO 9 FT TO PERSIST 
IN THE NW QUADRANT OF LOW CENTER.

$$
GR