000
AXPZ20 KNHC 181003
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC FRI SEP 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.               

...TROPICAL WAVES... 

A TROPICAL WAVE IS JUST E OF THE BASIN ACROSS THE EASTERN 
PORTIONS OF HONDURAS AND NICARAGUA MOVING W 15-20 KT. SCATTERED 
SHOWERS AND TSTMS ARE NOTED E OF THE WAVE WELL INTO THE SW 
CARIBBEAN SEA. THE WAVE IS FORECAST TO REACH NEAR 88W EARLY 
TONIGHT...AND TO NEAR 93W BY FRI NIGHT THEN BEGIN TO BECOME 
ILL-DEFINED LIKE THE PREVIOUS WAVE OF THE PAST FEW DAYS. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH AXIS EXTENDS W FROM COLOMBIA NEAR 11N74W TO 
09N82W TO 10N87W...WHERE IT BECOMES ILL DEFINED. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF TROUGH 
BETWEEN 84W-86W. 
 
...DISCUSSION...

AN ELONGATED AREA OF LOW PRES CENTERED SEVERAL HUNDRED MILES S 
OF THE SOUTHERN TIP OF CALIFORNIA REMAINS THE DOMINANT WEATHER 
FEATURE ACROSS THE AREA. THIS AREA OF LOW PRES CONSISTS OF 1008 
MB LOW NEAR 19N109W...AND A 1010 MB LOW NEAR 16N120W. ENERGY 
FROM A PREVIOUS TROPICAL WAVE ADDED TO THE FORMATION OF THIS 
AREA OF LOW PRES. LATEST SATELLITE IMAGERY IS SHOWING INCREASING 
CONVECTION IN CLUSTERS WITH THIS SYSTEM. THIS CONVECTION IS 
DEPICTED AS NUMEROUS STRONG TYPE INTENSITY FROM FROM 15N-17.5N 
BETWEEN 118W-121W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM 
OF A LINE FROM 14N111W TO 14N115W...AND WITHIN 30 NM OF A LINE 
FROM 17N109W TO 17N112.5W. THE 0508 UTC ASCAT PASS REVEALED 
GENERALLY LIGHT TO MODERATE WINDS AROUND THE AREA OF LOW PRES. 
MODERATE SW WINDS ALOFT AHEAD OF AN UPPER LEVEL TROUGH LOCATED N 
OF 17N BETWEEN 119W-128W ARE TRANSPORTING UPPER MOISTURE FROM 
THIS CONVECTION NNE TOWARDS CENTRAL BAJA CALIFORNIA...AND THE SW 
U.S. GLOBAL MODELS CONTINUE TO INDICATE THAT THIS ELONGATED AREA 
OF LOW PRES WILL ROTATE COUNTER CLOCKWISE...AND BECOME MORE NE 
TO SW ALIGNED TONIGHT THROUGH FRIDAY...AND CONTINUE TO ADVECT 
ABUNDANT TROPICAL MOISTURE TOWARDS CENTRAL AND SOUTHERN BAJA 
CALIFORNIA AS WELL AS THE ADJACENT GULF AND MEXICAN STATES TO 
THE E. THE MOISTURE SHOULD THEN SPREAD FARTHER NW-N ACROSS 
NORTHERN BAJA CALIFORNIA SAT AND SAT NIGHT AS THE ELONGATED LOW 
PRES AREA BEGINS TO SHIFT N-NW. INCREASING RAIN CHANCES SHOULD 
BE EXPECTED ACROSS THESE AREAS...EXTENDING INLAND ACROSS 
MAINLAND MEXICO TO THE W SLOPES OF THE SIERRA MADRES 
OCCIDENTALES...WITH THE POTENTIAL FOR HEAVY RAINS...FLASH 
FLOODING AND LANDSLIDES THROUGH THE WEEKEND. PRESENTLY... 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
SEEN ALONG AND JUST INLAND THE COAST OF MEXICO FROM 20N-25N.

WELL TO THE NW OF THE AFOREMENTIONED AREA OF LOW PRES...A 1023 
MB HIGH PRES CENTER IS ANALYZED N OF THE HAWAIIAN ISLANDS NEAR 
35N151W WITH A RIDGE EXTENDING SE TO NEAR 22N114W. THE PRES 
GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE TROPICS IS 
RESULTING IN FRESH TO STRONG NE TRADE WINDS WITHIN 150 NM NW OF 
A LINE FROM 18N135W TO 21N128W...WHERE SEAS ARE IN THE RANGE OF 
7-9 FT. THIS AREA OF FRESH TO STRONG NE TRADE WINDS IS FORECAST 
TO SHRINK IN COVERAGE THROUGH SUN. A WEAK SURFACE TROUGH IS OVER 
THE FAR WESTERN PORTION OF THE ROUGHLY ALONG 136W/137W FROM 12N-
19N. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE TROUGH 
FROM 11N-14N.
 
THE 0508 UTC ASCAT PASS ALSO SHOWED NW TO N WINDS OF 10-15 KT E 
OF THE RIDGE TO THE COAST OF BAJA CALIFORNIA WHERE SEAS ARE 
GENERALLY GENERALLY 4-5 FT IN MIXED SW AND NW SWELL AS SEEN IN 
RECENT ALTIMETER PASSES. THE RIDGE WILL CHANGE LITTLE THROUGH 
FRI BEFORE WEAKENING SAT AS THE N PORTION OF THE ELONGATED LOW 
PRES AREA LIFTS N OF 20N. HOWEVER...INCREASING WINDS ACROSS THE 
OFFSHORE WATERS OF CALIFORNIA WILL GENERATE A NEW PULSE OF NNW 
SWELL THAT WILL MOVE INTO NE PORTIONS OF THE DISCUSSION AREA 
OVER THE WEEKEND AND RAISE SEA HEIGHTS TO 6-8 FT...MAINLY W OF 
118W. OTHERWISE...SEAS WILL CONTINUE TO BE DOMINATED BY PULSES 
OF MODERATE SW SOUTHERN HEMISPHERIC SWELL.
  
$$
AGUIRRE