Tropical Weather Discussion
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000
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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