000
AXPZ20 KNHC 261005
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
1005 UTC TUE MAR 26 2013

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 
1000 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
THE MONSOON TROUGH EXTENDS FROM 09N83W TO 04N90W. THE ITCZ AXIS 
EXTENDS FROM 04N90W TO 02N102W TO 01N120W TO BEYOND 03N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S 
OF THE AXIS BETWEEN 131W-134W. SCATTERED MODERATE CONVECTION IS 
WITHIN 30 NM OF THE AXIS BETWEEN 121W-125W.

...DISCUSSION...                                             

A MID/UPPER TROUGH SLIDING EWD IS OVER THE ERN PORTION OF THE 
AREA FROM FAR NW MEXICO SSW TO 21N114W TO 15N118W TO 01N119W. TO 
ITS W...A SHORTWAVE RIDGE ALSO SLIDING EWD IS ROUGHLY ALONG 128W 
N OF 18N. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE 
SUBSIDENCE OVER THE ERN PART OF THE AREA N OF 09N E OF 122W. S 
OF 09N BETWEEN THE TROUGH AND 107W UPPER LEVEL DIVERGENCE THERE 
IS RESULTING IN MOSTLY BROKEN MID AND HIGH LEVEL CLOUDS 
STREAMING NEWD TOWARDS CENTRAL MEXICO...BUT DISSIPATE NEAR 105W 
AS THEY ENCOUNTER A DRIER ATMOSPHERE ASSOCIATED WITH THE 
AFOREMENTIONED MODERATE SUBSIDENCE. WIDELY SCATTERED SHOWERS AND 
ISOLATED TSTMS ARE POSSIBLE N OF THE ITCZ TO 06N BETWEEN 112W 
AND THE TROUGH. 

BROKEN MOSTLY HIGH LEVEL CLOUDS ARE STREAMING EWD N OF 12N AND W 
OF 122W. ISOLATED SHOWERS ARE POSSIBE FROM 15N-29N BETWEEN 126W-
135W.

BROAD UPPER LEVEL ANTICYCLONIC FLOW...ANCHORED BY AN AN 
ANTICYCLONE OVER NW COLOMBIA...COVERS THE FAR SE PORTION OF THE 
AREA. ASSOCIATED MODERATE TO STRONG SUBSIDENCE IS PRESENT THERE 
INHIBITING ANY DEEP CONVECTION OR ORGANIZED CLOUDINESS TO DEVELOP.
THE ONLY CONVECTIVE TYPE ACTIVITY NOTED IS THAT OF RECENT SMALL 
CLUSTERS OF TSTMS ALONG THE MONSOON TROUGH SEGMENT DESCRIBED 
ABOVE UNDER ITCZ/MONSOON TROUGH.

AT SURFACE TO LOWER LEVELS...A WEAK 1019 MB HIGH CENTER IS NEAR 
26N138W WITH A RIDGE SE TO SRN BAJA CALIFORNIA. A WEAKENING COLD 
FRONT HAS ENTERED THE FAR NW PORTION OF THE AREA ALONG 32N137W 
29N140W. ANOTHER COLD FRONT IS TO ITS NW JUST CROSSING 35N140W 
AS IT MOVES ESE. BESIDES A WIND SHIFT THAT WILL ACCOMPANY THE 
FIRST FRONT...NO SIGNIFICANT IMPACT ON WINDS AND SEAS IS 
EXPECTED FROM IT. THE SECONDARY COLD FRONT IS ALSO FORECAST TO 
BE ON THE WEAK SIDE WHEN IT MOVES INTO THE FAR NW PORTION TONIGHT
AS IT MERGES WITH THE REMNANTS OF THE FIRST FRONT...WITH VERY 
LITTLE IMPACT ON WINDS AND SEAS. THE WEAK 1019 MB HIGH IS 
FORECAST TO MOVE SW THROUGH WED AS ANOTHER SIMILAR TYPE HIGH 
FORMS OVER THE NE PORTION OF THE AREA. THIS TRANSLATES TO A WEAK 
PRES GRADEINT CONTINUING THROUGHOUT ALLOWING LIGHT WINDS AND
RELATIVELY LOW SEAS THROUGHOUT OVER THE NEXT COUPLE OF DAYS.

GAP WINDS...A VERY TIGHT PRES GRADIENT OVER THE ISTHMUS OF 
TEHUANTEPEC DUE TO STRONG HIGH PRES BUILDING SWD OVER THE FAR 
WESTERN GULF OF MEXICO IN THE WAKE OF A RECENT COLD IS INDUCING 
GALE FORCE WINDS THROUGH THE CHIVELA PASS...AND INTO THE GULF OF 
TEHUANTEPEC AS WAS NOTED BY THE 0548 UTC OSCAT PASS AND 0410 UTC 
ASCAT PASS FROM LAST NIGHT. IR SATELLITE IMAGERY TEMPERATURES 
SUGGEST THAT A TONGUE OF UPWELLING OF COLD SSTS IS PRESENT FROM
THE GULF SWD TO 14N AND BETWEEN 94W AND 96W INDICATED OF THE 
GALE FORCE N WINDS BLOWING ACROSS THE GULF OFF THE MEXICAN 
COAST. THE FORCE WINDS ARE REACHING UP TO 40 KT WITH SOME BRIEF
GUSTS TO 45 KT POSSIBLE.

SEAS IN THE GULF OF TEHUANTEPEC ARE FORECAST TO BUILD TO 12 FT 
BY LATE TONIGHT... AND TO 16 FT BY LATE TUE NIGHT. THE PRES 
GRADIENT IS FORECAST TO BEGIN TO SLACKEN LATE WED INTO THU 
ALLOWING FOR THE GALE CONDITIONS TO DIMINISH LATE THU MORNING 
INTO EARLY THU AFTERNOON.
 
$$
AGUIRRE