000
AXPZ20 KNHC 231548
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC WED SEP 23 2015

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 
1315 UTC.               

...TROPICAL WAVES... 

A TROPICAL WAVE WAS ANALYZED FROM 14N97W TO 05N99W. THE WAVE IS 
MOVING W AROUND 10-15 KT. SCATTERED MODERATE CONVECTION WAS 
NOTED WITHIN 240 NM E OF THE WAVE FROM 08N-11N AND WITHIN 180 NM 
W OF THE WAVE FROM 05N-14N.

A TROPICAL WAVE WAS ANALYZED ALONG 123W FROM 03N TO 15N. THE 
WAVE WAS MOVING W AROUND 10-15 KT. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS WITHIN 240 NM EITHER SIDE OF 
THE WAVE FROM 03N-15N. 

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

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N78W TO LOW PRES 
NEAR 10N91W 1007 MB TO 09N100W TO 11N113W. THE ITCZ AXIS WAS 
ANALYZED FROM 06N125W TO 04N138W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS BETWEEN 90 NM AND 270 NM S OF THE 
AXIS E OF 84W. SCATTERED MODERATE TO STRONG CONVECTION WAS FROM 
07N-14N BETWEEN 84W-94W.  

...DISCUSSION...

A 1008 MB SURFACE LOW WAS ANALYZED NEAR 14N133W. SCATTERED 
MODERATE CONVECTION WAS WITHIN 150 NM N AND NW QUADRANTS OF THE 
LOW CENTER. THE 0646 UTC ASCAT PASS SHOWED AN AREA OF 20-25 KT 
WINDS WITHIN 60 NM NW SEMICIRCLE OF THE LOW. THIS LOW WILL 
ENCOUNTER INCREASING NORTHEASTERLY SHEAR OVER THE NEXT TWO DAYS. 
WINDS SHOULD DIMINISH BELOW ADVISORY CRITERIA LATER TODAY...AND 
THE LOW SHOULD OPEN UP TO A TROUGH BY THU.

A WEAK SURFACE RIDGE EXTENDS FROM 1019 MB HIGH PRES NEAR 36N130W 
TO 21N112W. A COLD FRONT N OF THE AREA WILL PUSH THE SURFACE 
HIGH EASTWARD THROUGH THU AND KEEP THE RIDGE IN PLACE RATHER 
WEAK. THE COLD FRONT WILL MOVE INTO NW WATERS BY FRI. THE 
WEAKENED SURFACE RIDGE IS SUPPORTING MAINLY GENTLE TO MODERATE 
TRADE WINDS ELSEWHERE OVER MUCH OF THE AREA N OF 10N W OF 
110W...WITH AN OCCASIONAL FRESH NW BREEZE SEEN OFF THE PACIFIC 
COAST OF BAJA CALIFORNIA. THESE CONDITIONS WILL CHANGE LITTLE 
OVER THE NEXT TWO DAYS. 

A VAST AREA OF ACTIVE CONVECTION LIES ALONG THE MONSOON TROUGH E 
OF 100W. MOISTURE IS EXPECTED TO INCREASE ALONG THE MONSOON 
TROUGH OVER THE NEXT TWO DAYS. THE AREA OF GREATEST UPPER LEVEL 
DIVERGENCE IS EXPECTED TO SHIFT W AS THE ANTICYCLONE OVER N 
CENTRAL MEXICO MOVES INTO CENTRAL BAJA CALIFORNIA...CARRYING THE 
N TO S ORIENTED UPPER RIDGE AXIS WESTWARD WITH IT. 

GAP WINDS...                                                     
GULF OF TEHUANTEPEC...THE PRESSURE GRADIENT BETWEEN WEAK RIDGING 
IN THE GULF OF MEXICO...AND THE TROPICAL WAVE SW OF THE GULF OF 
TEHUANTEPEC IS FUNNELING NORTHERLY WIND THROUGH THE CHIVELA 
PASS...WITH STRONG TO NEAR GALE FORCE WINDS SEEN ACROSS THE GULF 
OF TEHUANTEPEC THIS MORNING. THESE WINDS WILL DIMINISH SLIGHTLY 
IN THE AFTERNOON HOURS AND RETURN TO NEAR GALE FORCE LATER IN 
THE EVENING...ESPECIALLY WITH THE ASSISTANCE OF NOCTURNAL 
DRAINAGE FLOW. SEAS ARE EXPECTED REMAIN IN THE 9-11 FT RANGE IN 
THE GULF OF TEHUANTEPEC THROUGH FRI MORNING. 
    
$$
SCHAUER