| HOME | ARCHIVES | FORECASTS | IMAGERY | ABOUT NHC | RECONNAISSANCE |

Eastern Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 310300
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC FRI JUL 31 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC. 

...SPECIAL FEATURES...                                           

THE CENTER OF TROPICAL STORM GUILLERMO AT 31/0300 UTC WAS NEAR 
10.8N 129.3W 991 MB...MOVING WNW OR 295 DEG AT 12 KT. MAXIMUM 
SUSTAINED WINDS HAVE INCREASED TO 60 KT WITH GUSTS TO 75 KT. 
GUILLERMO CONTINUES TO BECOME BETTER ORGANIZED AS IT REMAINS IN 
AN ENVIRONMENT CONDUCIVE FOR FURTHER STRENGTHENING AND IS 
FORECAST TO BECOME A HURRICANE BY FRI MORNING. NUMEROUS STRONG 
CONVECTION WAS NOTED WITHIN 90 NM OF THE CENTER...EXCEPT 120 NM 
IN THE NE QUADRANT. ELSEWHERE SCATTERED MODERATE TO STRONG 
CONVECTION WAS NOTED WITHIN 180 NM IN THE N AND 210 NM IN THE S 
SEMICIRCLES. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADER MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. 

THE CENTER OF POST-TROPICAL CYCLONE EIGHT-E CONTINUES TO MOVE 
WESTWARD AWAY FROM THE AREA WITH THE LOW LEVEL CIRCULATION 
WEAKENING. THE SURFACE PRESSURE GRADIENT TO THE NORTH INDUCED BY 
THE NE PACIFIC RIDGE MAINTAINING A NARROWING ZONE OF 20-25 KT 
WINDS AND SEAS TO 10 FT OVER THE FORECAST WATERS FROM 17N TO 24N 
W OF 135W. THESE WINDS AND SEAS ARE EXPECTED TO SUBSIDE AND MOVE 
W OF THE AREA OVERNIGHT OR EARLY FRI.  

...TROPICAL WAVES...

TROPICAL WAVE ALONG 94W N OF 09N MOVING WEST 15-20 KT. THE 
CONVECTIVE PRECIPITATION ASSOCIATED WITH THE WAVE IS DESCRIBED 
IN THE MONSOON TROUGH SECTION.

TROPICAL WAVE ALONG 107W FROM 05N TO 14N MOVING WEST 15 KNOTS. 
CONVECTIVE PRECIPITATION ASSOCIATED WITH THE WAVE IS DESCRIBED 
IN THE MONSOON TROUGH SECTION.

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

MONSOON TROUGH FROM 10N85W TO 09N95W TO 06N106W. SCATTERED 
MODERATE TO STRONG FROM 06N TO THE COAST OF COSTA RICA BETWEEN 
83W AND 88W. SCATTERED MODERATE WITHIN 90 NM OF THE AXIS BETWEEN 
92W AND 95W...AND FROM 09N TO 14N BETWEEN 100W AND 104W. 

...DISCUSSION...

A WEAKENED SURFACE RIDGE CENTERED ACROSS THE NE PACIFIC EXTENDS 
SE INTO THE AREA AND PASSES THROUGH 30N134W TO 21N113W. THE 
SLACKENED PRESSURE GRADIENT BETWEEN THE RIDGE AND THE TYPICAL 
TROUGH THAT IS SEEN ALONG BAJA CALIFORNIA HAS ALLOWED NW WINDS 
TO SUBSIDE DURING THE PAST 12-24 HOURS TO THE 10-15 KT RANGE 
WITHIN ABOUT 180 NM W OF THE BAJA CALIFORNIA PENINSULA WITH 
RESULTANT SEAS OF 5 TO 6 FT. THE RIDGE WILL BEGIN TO SLOWLY 
STRENGTHEN ACROSS THIS REGION BEGINNING TONIGHT...WITH THE NWLY 
FLOW SLOWLY INCREASING OFFSHORE OF THE BAJA PENINSULA...POSSIBLY 
REACHING 20 KT WITH POCKETS TO 25 KT LATE FRI AFTERNOON AND 
NIGHT...WITH SEAS BUILDING TO NEAR 8 FT.

AS MENTIONED ABOVE...THE SURFACE PRESSURE GRADIENT THAT EXISTS 
BETWEEN THE SUBTROPICAL RIDGE AND LOWER SURFACE PRESSURES 
ASSOCIATED WITH TROPICAL DEPRESSION EIGHT-E IS RESULTING A  
SWATH OF 20 TO 25 KT TRADE WINDS IN THE FAR WESTERN PART OF THE 
AREA FROM 17N TO 24N AND TO THE WEST OF 135W. THE WINDS WILL 
GRADUALLY MOVE W OF THE AREA BY FRI...BEFORE FRESHENING AGAIN S 
OF 20N ON FRI AS GUILLERMO CONTINUES WNW AND TRACKS W OF 130W. 

GAP WINDS...                                                    
THE GULF OF PAPAGAYO...STRONG TRADE WINDS ACROSS THE SOUTHERN 
CARIBBEAN CONTINUE TO FUNNEL ACROSS THE HIGHER TERRAIN OF 
CENTRAL AMERICA AND SPILL ACROSS THE PACIFIC COASTAL WATERS THAT 
ARE TO THE EAST OF 90W. THE WINDS IN THIS AREA HAVE INCREASED  
AGAIN OVERNIGHT TO 20-25 KT ACROSS THE NICARAGUAN COASTAL WATERS 
IN THE LEE OF LAKES NICARAGUA AND MANAGUA...WILL DIMINISH BY 
LATE AFTERNOON...AND THEN INCREASE AGAIN TO AROUND 20 KT WITH 
ISOLATED AREAS TO 25 KT FRIDAY NIGHT. SEAS DOWNWIND OF THIS 
REGION WILL FLUCTUATE AT 6 TO 8 FT OVER THE NEXT 36 HOURS.

A NARROW PLUME OF NORTHERLY WINDS HAS DECREASED IN THE GULF OF 
TEHUANTEPEC LEAVING A SWATH OF 8 FT SEAS. THE SEAS WILL SUBSIDE 
TO LESS THAN 8 FT TONIGHT. THE NEXT PULSE WILL OCCUR FRI NIGHT 
INTO SAT WITH NORTHERLY WINDS OF ABOUT 20 KT AND SEAS LESS 
THAN 8 FT EXPECTED.

$$ 
COBB

Standard version of this page

Alternate Formats
About Alternates - E-Mail Advisories - RSS Feeds

Cyclone Forecasts
Latest Advisory - Past Advisories - About Advisories

Marine Forecasts
Latest Products - About Marine Products

Tools & Data
Satellite Imagery - US Weather Radar - Aircraft Recon - Local Data Archive - Forecast Verification - Deadliest/Costliest/Most Intense

Learn About Hurricanes
Storm Names Wind Scale - Prepare - Climatology - NHC Glossary - NHC Acronyms - Frequently Asked Questions - AOML Hurricane-Research Division

About Us
About NHC - Mission/Vision - Other NCEP Centers - NHC Staff - Visitor Information - NHC Library

Contact Us


NOAA/ National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Friday, 31-Jul-2015 03:01:07 UTC