000
AXPZ20 KNHC 081607
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC WED APR 08 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 1545 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
          
THE ITCZ EXTENDS FROM 05N86W TO 02N96W TO 05N106W TO 03N117W TO 
04N130W TO BEYOND 04N140W. SCATTERED STRONG CONVECTION IS WITHIN 
120 NM N OF ITCZ BETWEEN 106W-110W. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION IS WITHIN 150 NM N OF ITCZ BETWEEN 134W-136W 
...AND ALSO WITHIN 30 NM OF ITCZ BETWEEN 124W-127W. 

...DISCUSSION... 

A RATHER PROGRESSIVE SPRING UPPER PATTERN IS EVIDENT THIS 
MORNING ACROSS THE REGION. A FAST MOVING UPPER LOW IS 30N138W 
WITH A TROUGH TO SW OF THE AREA AT 23N140W AS CLEARLY SEEN ON 
WATER VAPOR IMAGERY. THIS FEATURE IS TO THE SE OF A RATHER 
ROBUST AND ALSO RAPIDLY SE MOVING UPPER TROUGH THAT IS FAST 
APPROACHING THE FAR NW CORNER OF THE DISCUSSION AREA. THIS 
TROUGH SUPPORTS A WELL DEFINED COLD FRONT LOCATED ABOUT 250 NM 
NW OF THE AREA. MID/UPPER LEVEL RIDGING SLIDING EASTWARD IS 
NOTED TO THE ENE OF THE UPPER LOW AND TROUGH. A JET STREAM 
BRANCH STRETCHES INTO THE AREA AT 18N140W...AND CONTINUES TO 
24N126W TO 26N120W AND TO ACROSS BAJA CALIFORNIA AT 28N114W AND 
TO NW MEXICO AND WELL ACROSS THE CENTRAL MID-WEST REGION OF THE 
U.S. MODERATE TO STRONG SW WINDS ALONG AND TO THE SE OF THIS JET 
STREAM ARE ADVECTING AMPLE DEEP MOISTURE IN THE FORM OF 
OVERCAST/MID UPPER CLOUDS...SEEN WITHIN 400 NM S AND SE OF THE 
JET STREAM. SCATTERED SHOWERS AND ISOLATED TSTMS ARE POSSIBLE 
WITHIN 350 NM SE OF THE JET STREAM BETWEEN 115W-128W WHERE 
DIVERGENCE ALOFT SE OF THE UPPER TROUGH IS LIKELY TO INDUCE SUCH 
ACTIVITY.

THE UPPER LOW NEAR 30N138W IS FORECAST TO TRACK NE TO NEAR 
33N125W WHERE IT WILL WEAKEN TO A TROUGH. THE UPPER TROUGH NW OF 
THE AREA WILL SWEEP ACROSS THE FAR NW PORTION THU NIGHT INTO FRI 
AS IT QUICKLY EVOLVES INTO A PRETTY STRONG UPPER LOW. THE GLOBAL 
MODELS REFLECT THIS FEATURE AS A NEW SURFACE LOW THAT NEARS THE 
NW PART OF THE AREA BY EARLY ON FRI WITH DIFFERENCES SEEN IN THE 
MODELS WITH EXACT LOCATION AND PRES OF THE LOW AT THAT TIME. THE 
COLD FRONT CURRENTLY NW OF THE AREA WILL MOVE ACROSS THE FAR NW 
PART OF THE AREA BY EARLY ON THU...THEN REACH FROM NEAR 32N128W 
TO 25N134W...AND CONTINUE WESTWARD AS A WEAKENING FRONT TO 
24N140W BY EARLY ON FRI. A TIGHT PRES GRADIENT BETWEEN THE LOW 
AND STRONG HIGH PRES TO ITS W WILL INITIATE STRONG NW-N FLOW 
ALONG AND N OF 29N BY EARLY ON FRI. WAVEWATCH GUIDANCE SHOWS 
BUILDING SEAS WITH THIS FLOW TO AFFECT THE NW PORTION BEGINNING 
EARLY ON FRI.

ELSEWHERE AT THE SURFACE...A DISSIPATING COLD FRONT DISSECTS 
HIGH PRES OVER THE NE WATERS. THE FRONT EXTENDS FROM THE 
CALIFORNIA/ARIZONA BORDER SW TO NORTHERN BAJA CALIFORNIA...AND  
CONTINUES SW TO 29N122W AND WNW TO NEAR 30N132W. ISOLATED 
SHOWERS ARE POSSIBLE WITHIN 60 NM OF THE FRONT. A STATIONARY 
1021 MB HIGH CENTER ASSOCIATED WITH THE RIDGE IS ANALYZED AT 
27N128W WHILE A 1022 MB HIGH IS LOCATED JUST N OF THE AREA AT 
34N128W. THIS HIGH IS FORECAST TO MOVE SEWD WHILE WEAKENING TO 
1019 MB NEAR 33N124W IN 24 HOURS. HIGH PRES REMAINS THE DOMINATE 
FEATURE AT THE SURFACE COVERING THE AREA N OF ABOUT 16N AND W OF 
114W. A TROUGH IS ANALYZED FROM 15N126W TO 04N129W. ISOLATED 
SHOWERS AND WEAK TSTMS ARE WITHIN 60-90 NM OF THE TROUGH.

EXPECT SEAS TO 8 FT IN MIXED SE..SW AND NW SWELLS FROM 08N TO 
14N BETWEEN 118W-124W...FROM 10N-15N BETWEEN 120W-136W IN 24 
HOURS...AND FROM 09N-13N BETWEEN 125W-137W IN 48 HOURS.

GAP WINDS...                                                     
THE GULF OF TEHUANTEPEC...N-NE WINDS OF 20-25 KT THROUGH THE 
GULF ARE FORECAST TO DIMINISH BY EARLY THIS EVENING WITH SEAS 
LOWERING TO LESS THAN 8 FT.

THE GULF OF PAPAGAYO...EXPECT PULSES OF NORTHEAST WINDS 20 TO 25 
KNOTS...AND WAVEHEIGHTS TO 9 FT TILL EARLY TONIGHT BEFORE 
DIMINISHING TO 20 KT OR LESS AND SEAS LESS THAN 8 FT. THESE 
CONDITIONS THEN MATERIALIZE AGAIN EARLY ON WED AND SUBSIDE WED 
EVENING...AND START UP AGAIN DURING THE EARLY MORNING HOURS OF 
FRI.

THE GULF OF CALIFORNIA...EXPECT NW WINDS 20 TO 25 KNOTS AND SEA 
HEIGHTS LOWER THAN 8 FEET FROM 24N TO 25N E OF 108W BEGINNING 
THU NIGHT AND INTO EARLY ON FRI.

$$
AGUIRRE