Tropical Weather Discussion
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000
AXPZ20 KNHC 010255
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT AUG 01 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
0230 UTC.

...SPECIAL FEATURES...

AT 0300 UTC AUG 01....HURRICANE GUILLERMO WAS CENTERED NEAR
13.2N 136.1W...OR ABOUT 1160 NM...2150 KM ESE OF HILO HAWAII
MOVING WNW OR 285 DEG AT 17 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE WAS 970 MB WITH MAXIMUM SUSTAINED WINDS REMAINING 90 KT
WITH GUSTS TO 110 KT...WITH GUILLERMO A CATEGORY TWO HURRICANE
ON THE SAFFIR-SIMPSON SCALE. GUILLERMO IS FORECAST TO INTENSIFY
SLIGHTLY POSSIBLY REACHING MAJOR HURRICANE STATUS ON
SAT...BEFORE BEGINNING A SLOW WEAKENING TREND THROUGH THE
REMAINDER OF THE WEEKEND.  CONVECTIVE ACTIVITY ASSOCIATED WITH
THE STORM HAS BEEN NEARLY STEADY WITH SOME ASYMMETRY NOTED IN
THE CONVECTION. THE INTERMITTENT EYE FEATURE NOTED EARLIER HAS
DISAPPEARED. CURRENTLY...NUMEROUS STRONG CONVECTION WAS NOTED
WITHIN 90 NM OF CENTER IN THE W SEMICIRCLE AND 60 NM IN THE E
SEMICIRCLE. AN AREA OF SCATTERED STRONG CONVECTION WAS WELL
REMOVED FROM THE CENTER...IN AN AREA FROM 15N TO 18N BETWEEN
128W AND 133W. PLEASE READ THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADER MIATCMEP4/WTPZ24 KNHC FOR ADDITIONAL
DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 102W FROM 17N SOUTHWARD...MOVING
WESTWARD 15 TO 20 KNOTS. SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS FROM 10N TO 13N WITHIN 120 NM EITHER SIDE OF WAVE
AXIS.

A TROPICAL WAVE IS ALONG 112 FROM 05N TO 13N...MOVING WESTWARD
15 KNOTS. NO SIGNIFICANT CONVECTION IS DIRECTLY ASSOCIATED WITH
THE WAVE.

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

MONSOON TROUGH FROM 10N85W TO 07N93W TO 09N102W TO 07N110W.
SCATTERED MODERATE ISOLATED STRONG WITHIN 240 NM EITHER SIDE OF
AXIS BETWEEN 102W AND 110W...AND WITHIN 120 NM S OF AXIS BETWEEN
90W AND 98W.

...DISCUSSION...

A WEAK SURFACE RIDGE EXTENDS FROM A 1020 MB HIGH PRESSURE
CENTERED NEAR 28N125W TO 18N113W. THE GRADIENT BETWEEN THE RIDGE
AND LOWER PRESSURE ALONG THE MONSOON TROUGH IS FAIRLY WEAK WITH
ONLY MODERATE TRADES NOTED AND SEA HEIGHTS OF 6 TO 7 FEET. THE
GRADIENT BECOMES MORE PRONOUNCED W OF 128W BETWEEN THE RIDGE AND
THE WESTWARD MOVING HURRICANE GUILLERMO. A BROAD SWATH OF 20 TO
30 KT WINDS AND SEAS GREATER THAN 8 FT EXTEND WELL N OF THE
HURRICANE OVER THE EAST PACIFIC FROM 15N TO 20N BETWEEN 125W AND
138W.

A SURFACE HIGH IS EXPECTED TO REMAIN IN PLACE THROUGH SUN.
HOWEVER SOME INCREASE IN THE GRADIENT BETWEEN THE HIGH AND LOWER
SURFACE PRESSURES OVER MEXICO IS FORECAST TO DEVELOP WITHIN 120
NM OF THE COAST OF BAJA CALIFORNIA SAT NIGHT AND SUN WITH NW
WINDS OF 20 KT FORECAST TO DEVELOP WITH SEAS REMAINING BELOW 8
FT.

CROSS-EQUATORIAL SWELL WILL INCREASE SEAS TO 7-8 FT ACROSS THE
TROPICS S OF 06N BETWEEN 95-130W TODAY AND CONTINUE N REACHING
ALONG 10N BY SUN.

GAP WINDS...
WINDS IN THE THE GULF OF PAPAGAYO HAVE DROPPED TO 15-20 KT WITH
THE AREA OF RESIDUAL SEAS SUBSIDING BELOW 8 FT. THE WINDS AND
SEAS ARE FORECAST TO REMAIN BELOW CRITERIA FOR THE HIGH SEAS
THROUGH 48 HOURS.

$$
COBB


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