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000
AXPZ20 KNHC 290259
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI MAY 29 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 0200 UTC.


...SPECIAL FEATURE...

TROPICAL STORM ANDRES IS CENTERED NEAR 11.8N 113.3W AT 29/0300 UTC MOVING W-NW OR 290 DEG AT 9 KT AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH TONIGHT WITH A TURN TOWARD THE NW ON FRI. ESTIMATED MINIMAL CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. NUMEROUS STRONG CONVECTION IS NOTED WITHIN 60 NM NE SEMICIRCLE OF CENTER AND IN A BAND WITHIN 45 NM EITHER SIDE OF LINE FROM 09N112W TO 11N114W TO 12N115W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ELSEWHERE WITHIN 300 NM NE AND 270 NM SW SEMICIRCLES OF CENTER. ANDRES IS FORECAST TO STRENGTHEN FURTHER OVER THE NEXT 24 HOURS...AND IS EXPECTED TO BECOME A HURRICANE ON FRIDAY. REFER TO LATEST NHC PUBLIC/ FORECAST ADVISORIES UNDER AWIPS/WMO HEADERS MIATCPEP1/MIATCMEP1 AND WTPZ31/WTPZ21 KNHC FOR MORE DETAILS.


...TROPICAL WAVES/LOWS...

A TROPICAL WAVE EXTENDS FROM 05N TO 13N ALONG 99W/100W AND HAS BEEN PROGRESSING W AT 10 KT OVER THE PAST 24 HOURS. CURRENTLY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 10N TO 13N BETWEEN 99W AND 103W. SIMILAR CONVECTION IS SEEN E OF THE AXIS NEAR 09N98W. THE WAVE IS FORECAST TO CONTINUE W TONIGHT AND GRADUALLY LOSE IDENTITY AS IT BECOMES ABSORBED INTO THE BROADER CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL STORM ANDRES.

A 1008 MB LOW PRES IS LOCATED NEAR 11N135W. CONVECTION HAS DIMINISHED IN ASSOCIATION WITH THIS LOW AND NOW ONLY SCATTERED SHOWERS ARE NEAR THE CENTER. THE PRES GRADIENT BETWEEN THE RIDGE TO THE N AND THIS LOW IS MAINTAINING AN AREA OF NE-E 20-25 KT TRADES FROM 11N TO 17N W OF 134W WITH COMBINED SEAS TO 9 FT. THE LOW IS FORECAST TO CONTINUE W-SW TO NEAR 10N138W FRI EVENING AND NEAR 09N140W ON SAT EVENING.


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

CURRENTLY THERE IS NOT A WELL DEFINED MONSOON TROUGH OR ITCZ. A SURFACE LOW OVER NORTHERN COLOMBIA HAS AN ASSOCIATED TRAILING TROUGH EXTENDING SW ACROSS THE EPAC TO NEAR 03N82W. SCATTERED MODERATE CONVECTION IS NEAR THE SOUTHERN END OF THE TROUGH FROM 03N TO 05N BETWEEN 81W AND 83W.


...DISCUSSION...

A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE N WATERS WITH THE SECOND TROUGH AXIS OVER N-CENTRAL MEXICO. AN UPPER ANTICYCLONE IS CENTERED OVER THE TROPICS NEAR 14N103W WITH AN UPPER RIDGE EXTENDING WESTWARD TO BEYOND 10N140W. AN UPPER RIDGE ALSO EXTENDS E TO A CREST EASTWARD TO 10N90W. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING CONVECTION ASSOCIATED WITH TROPICAL STORM ANDRES AND PROVIDING A FAVORABLE ENVIRONMENT FOR INTENSIFICATION...REFER TO THE SPECIAL FEATURES SECTION ABOVE FOR ADDITIONAL INFORMATION ON ANDRES.

BROAD SURFACE RIDGE ANCHORED BY 1019 MB HIGH PRES CENTERED NEAR 28N130W EXTENDS A RIDGE ACROSS THE NORTH WATERS TO NEAR 21N112W. THE HIGH PRES IS FORECAST TO REMAIN NEARLY STATIONARY OVER THE NEXT 24 HOURS.

A SURFACE TROUGH IS ANALYZED FROM 12N122W TO 08N125W. CONVECTION HAS DEVELOPED ON EITHER SIDE OF THE TROUGH AXIS. SATELLITE IMAGERY SHOWS NUMEROUS MODERATE ISOLATED STRONG CONVECTION W OF AXIS FROM 08N TO 11N BETWEEN 125W AND 128W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS E OF AXIS FROM 08N TO 11N BETWEEN 119W AND 123W.

$$ GR

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