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AXPZ20 KNHC 292155
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC.


...TROPICAL WAVES... TROPICAL WAVE OVER SE MEXICO ALONG 97W N OF 12N MOVING W NEAR 20 KT. CONVECTION IS LIMITED NEAR THE SOUTHERN END OF THE WAVE AXIS.

A SECOND TROPICAL WAVE EXTENDS FROM 17N112W TO 06N113W. A 1010 MB LOW PRES IS ALONG WAVE AXIS NEAR 11N. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 06N TO 10N BETWEEN 110W AND 118W. THE WAVE AND ASSOCIATED LOW PRES WILL CONTINUE TO MOVE WESTWARD APPROACHING 120W LATE WED.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 07N78W TO 08N91W. THE ITCZ CONTINUES FROM 08N91W TO LOW PRES NEAR 11N113W TO LOW PRES NEAR 11N128W TO 11N136W. SCATTERED MODERATE FROM 05N TO 07N BETWEEN 78W AND 81W. SIMILAR CONVECTION IS FROM 11N TO 13N BETWEEN 100W AND 107W.


...DISCUSSION...

HERNAN WAS DOWNGRADED TO A REMNANT LOW AT 29/1500 UTC AND THE LAST ADVISORY WAS ISSUED BY THE NATIONAL HURRICANE CENTER ON THIS SYSTEM. A 1010 MB LOW PRES IS ANALYZED ON THE 1800 UTC SURFACE MAP NEAR 24N122W. AN AREA OF FRESH TO STRONG WINDS WITH SEAS OF 8-11 FT IS STILL NOTED WITHIN 120 NM N SEMICIRCLE OF THE LOW CENTER. WINDS AND SEAS ARE FORECAST TO GRADUALLY DIMINISH IN ASSOCIATION WITH THIS SYSTEM AND THE LOW PRES IS EXPECTED TO DISSIPATE IN ABOUT 36-48 HOURS. FOR ADDITIONAL INFORMATION ON THIS REMNANT LOW PLEASE SEE HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFEPI AND WMO HEADER FZPN01 KWBC.

A 1010 MB LOW PRES IS WITHIN THE ITCZ NEAR 11N128W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM SW QUADRANT OF LOW CENTER. SCATTERED MODERATE CONVECTION IS ALSO NOTED ELSEWHERE FROM 08N TO 10N BETWEEN 128W AND 132W. VISIBLE SATELLITE IMAGERY SHOWS SOME BANDING FEATURES AND THE 1748 UTC ASCAT PASS INDICATED WINDS OF 20-25 KT WITHIN 120 NM NW QUADRANT OF THE LOW CENTER WITH SEAS T0 8 FT. THE LOW WILL MOVE GENERALLY WEST MAINTAINING AN AREA OF FRESH TO STRONG WINDS WITHIN AROUND 120 NM TO THE N OF THE CENTER.

ANOTHER 1011 MB LOW PRES IS LOCATED NEAR 15N139W. PRES GRADIENT BETWEEN THE LOW PRES AND A RIDGE OVER THE NW WATERS IS RESULTING IN AN AREA OF FRESH TO STRONG WINDS OF 20-25 KT FROM 15N TO 20N W OF 135W WITH SEAS OF 8-10 FT. THE LOW IS FORECAST TO MOVE W OF 140W OVERNIGHT TONIGHT. WINDS AND SEAS WILL DIMINISH ACROSS THE FORECAST AREA IN ABOUT 24 HOURS.

ALOFT...AN UPPER LEVEL TROUGH REMAINS IN PLACE ACROSS THE N- CENTRAL PART OF THE AREA EXTENDING FROM 30N128W TO 20N124W TO 15N128W. MOSTLY DRY AIR ACCOMPANIES THIS TROUGHING GENERALLY N OF 15N BETWEEN 125W AND 131W. SLY WINDS AHEAD OF THIS TROUGH CONTINUES TO IMPACT THE REMNANT OF HERNAN. AN UPPER LEVEL RIDGE FOLLOWS THIS TROUGH WITH AXIS ROUGHLY ALONG 135W. AN ANTICYCLONIC CIRCULATION IS NOTED OVER NORTHERN CHIHUAHUA WITH A RIDGE EXTENDING ACROSS NORTHERN MEXICO INTO THE EPAC TO NEAR 24N115W. THE UPPER-LEVEL LOW THAT WAS LOCATED OVER SOUTH-CENTRAL MEXICO YESTERDAY HAS MOVED WWD AND NOW IS CENTERED NEAR 19N108W. UPPER DIFFLUENCE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ AND NEAR THE LOW PRES SYSTEMS PREVIOUSLY MENTIONED.

MIXED SW AND SE SWELL FROM THE SOUTHERN HEMISPHERE CONTINUES TO IMPACT THE SOUTH-CENTRAL WATERS S OF 02N BETWEEN 110W AND 120W WITH SEAS TO 8 FT THROUGH TODAY.

SCATTERED MODERATE CONVECTION FROM 13N TO 15N W OF 139W REMAINS NEAR A 1011 MB LOW NEAR 16N139W WITH FRESH TO STRONG WINDS PERSISTING N OF THE LOW MOSTLY DUE TO PRESSURE GRADIENT BETWEEN THE LOW AND SUBTROPICAL RIDGE N OF THE AREA. SEAS ARE 8 TO 10 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 BY EARLY MORNING WED.

WINDS WILL CONTINUE TO PULSE ACROSS THE GULF OF PAPAGAYO... PARTICULARLY DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW. WINDS HAVE DIMINISHED TO 20 KT OR LESS ACROSS THE GULF OF TEHUANTEPEC AS THE TROPICAL WAVE MOVES W OF THIS REGION.

$$ GR

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