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AXPZ20 KNHC 290903
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUL 29 2014

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 0830 UTC.


...SPECIAL FEATURES... TROPICAL STORM HERNAN CENTERED NEAR 22.1N 118.6W OR ABOUT 370 NM W OF SOUTHERN TIP OF BAJA CALIFORNIA MOVING WNW OR 300 DEGREES AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WINDS 40 KT GUSTS 50 KT. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 105 NM NE OF CENTER. INCREASINGLY HOSTILE ENVIRONMENTAL CONDITIONS INCLUDING COOLER SEA TEMPERATURES AND PERSISTENT VERTICAL WILL CAUSE THIS SYSTEM TO WEAKEN RAPIDLY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS.


...TROPICAL WAVES... TROPICAL WAVE N OF 08N ALONG 93W. SCATTERED MODERATE ISOLATED STRONG CONVECTION N OF 11N WITHIN 180 NM E OF WAVE AXIS. THE WAVE WILL CONTINUE TO MOVE WESTWARD AT 15 KT REACHING NEAR 95W BY LATE TUE AND 100W WED.

TROPICAL WAVE EXTENDS FROM 07N TO 15N ALONG 110W. A 0515 UTC ASCAT SATELLITE PASS INDICATED SHARP CYCLONIC TURNING IN THE WIND FIELD NEAR 10N112W ALONG THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS OBSERVED FROM 10N TO 13N BETWEEN 109W AND 111W. THE WAVE WILL MOVE WEST AT 15 KT. WEAK LOW PRES AREA EXPECTED TO DEVELOP NEAR WHERE THE WAVE MEETS THE ITCZ AXIS BY EARLY WED.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 09N84W TO 07N97W. THE ITCZ AXIS EXTENDS FROM 07N97W TO 10N108W...THEN IS DISCONTINUOUS RESUMING AT 09N116W TO LOW PRES NEAR 11N126W 1012 MB. SCATTERED MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 120 NM W OF LOW NEAR 11N126W.


...DISCUSSION... AN UPPER LEVEL TROUGH REMAINS IN PLACE FROM 30N125W TO 16N125W...DELIVERING DEEP LAYER DRY AIR ACROSS MUCH OF THE DISCUSSION AREA N OF THE ITCZ W OF 120W. DIVERGENCE ALOFT AT THE BASE OF THE UPPER TROUGH IS ENHANCING CONVECTION IN THE RELATIVELY MOIST AREAS ALONG THE ITCZ NEAR THE LOW AT 11N126W.

PERSISTENT SHEAR AHEAD OF THE UPPER TROUGH...ALONG WITH COOLER WATER TEMPERATURES AND MORE STABLE AIR ARE TOGETHER CONTRIBUTING TO THE WEAKENING TREND OBSERVED WITH TROPICAL STORM HERNAN. HERNAN IS EXPECTED TO WEAKEN TO A DEPRESSION OVER THE NEXT SEVERAL HOURS.

NO SIGNIFICANT CONVECTION REMAINS NEAR A 1012 MB LOW PRES AREA NEAR 15N138W BUT AN ASCAT SATELLITE PASS YESTERDAY AFTERNOON INDICATED THAT FRESH TO STRONG WINDS PERSISTED WITHIN 240 NM IN THE NORTHERN QUADRANT OF THE LOW...DUE TO PRES GRADIENT BETWEEN THE LOW AND SUBTROPICAL RIDGE N OF THE AREA. SEAS ARE 8 TO 11 FT IN THIS AREA OF ENHANCED TRADES. THE LOW WILL MOVE W OF THE AREA THROUGH TODAY WITH DIMINISHING WINDS AND SEAS N OF THE LOW OVERNIGHT.

N WINDS TO 25 KT ARE EXPECTED TO PULSE IN THE GULF OF TEHUANTEPEC WITH SEAS BELOW 8 FT ASSOCIATED WITH APPROACHING TROPICAL WAVE. WINDS ARE ALSO EXPECTED AROUND 20-25 KT IN THE GULF OF PAPAGAYO...THEN AGAIN TONIGHT WITH SEAS TO 8 FT DURING EACH PULSE.

MIXED SW AND SE SWELL FROM THE SOUTHERN HEMISPHERE CONTINUES TO IMPACT THE SOUTH-CENTRAL WATERS S OF 02N BETWEEN 115W AND 120W WITH SEAS TO 8 FT THROUGH TODAY.

$$ CHRISTENSEN

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