Tropical Weather Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AXPZ20 KNHC 012145
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED APR 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2145 UTC.

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

THE ITCZ WAS ANALYZED FROM 02N102W TO 00N117W WITH ONLY ISOLATED
MODERATE CONVECTION FLARING INTERMITTENTLY ALONG ITS AXIS.

A SURFACE TROUGH EXTENDS SW OFF THE COAST OF COLOMBIA FROM
05N77W TO 01N82W. SCATTERED MODERATE CONVECTION IS OBSERVED
WITHIN 30 NM OF THE TROUGH.

A SECOND TROUGH EXTENDS SW FROM THE COAST OF COSTA RICA AT
10N85W TO 02N99W. ISOLATED MODERATE TO STRONG CONVECTION
IS OBSERVED WITHIN 120 NM EITHER SIDE OF A LINE FROM
08.5N83.5W TO 01N97.5W.

A THIRD TROUGH IS NOTED IN THE DEEP TROPICS FROM 14N124W TO
03N123W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED
E OF THE TROUGH WITHIN 120 NM EITWRKHER SIDE OF A LINE FROM
08N123W TO 13.5N121W.

SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 30 NM EITHER
SIDE OF A LINE FROM 01N120W TO 08N122W. ISOLATED MODERATE TO
STRONG CONVECTION IS NOTED WITHIN 60 NM OF LINE FROM 09N126W
TO 07N135W.

...DISCUSSION...

ALOFT...A PAIR OF WEAK UPPER LEVEL SHORT WAVE TROUGHS ARE
OBSERVED OVER THE SUBTROPICAL PORTION OF THE DISCUSSION AREA.
THE EASTERNMOST TROUGH IS PASSING E ACROSS NORTHERN MEXICO...
AND THE WESTERNMOST TROUGH IS JUST W OF THE DISCUSSION AREA
ALONG 144W. A WEAK UPPER RIDGE IS NOTED BETWEEN THESE TROUGHS
WITH NEARLY ZONAL FLOW...WHICH IS ADVECTING A LARGE PLUME OF
UPPER MOISTURE EASTWARD. THIS MOISTURE SHOULD PASS ACROSS THE
NORTHERN BAJA CALIFORNIA PENINSULA AND GULF OF CALIFORNIA
TONIGHT.

AN UPPER TROUGH IS OBSERVED OVER THE TROPICS FROM 22N122W TO
08N126W. AN ASSOCIATED LOW LEVEL TROUGH EXTENDS FROM 14N124W TO
03N123W...AND WAS PREVIOUSLY DESCRIBED. UPPER LEVEL DIVERGENCE E
OF THE UPPER TROUGH IS ENHANCING THE CONVECTION PREVIOUSLY
MENTIONED...WITH THE DEBRIS MOISTURE ADVECTED N BETWEEN 112-124W
TO ALONG 21N...THEN TURNS NE AND LATER E IN THE UPPER ZONAL
FLOW...WITH THE MOISTURE CONTINUING E ACROSS CENTRAL MEXICO. IT
APPEARS THAT THE LOW AND UPPER FEATURES ARE DECOUPLING....AND
SHOULD EXPECT A DECREASE IN CONVECTION.

AN UPPER ANTICYCLONE IS OVER NW COLOMBIA WITH AN UPPER RIDGE
EXTENDING NW TO A CREST AT 20N119W. DEBRIS MOISTURE FROM THE
CONVECTION ASSOCIATED WITH THE SURFACE TROUGHS...PREVIOUSLY
DESCRIBED...IS ADVECTED N AND NE ACROSS THE RIDGE AND OVER
CENTRAL AMERICA.

AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 32N130W TO
14N97W. THE PRESSURE GRADIENT E OF THE RIDGE IS SUPPORTING
NORTHERLY 20-25 KT WINDS ACROSS THE DISCUSSION AREA FROM 29-32N
BETWEEN 120-126W...WITH COMBINED SEAS OF 10-13 FT. LITTLE CHANGE
EXPECTED TONIGHT AND THU...THEN THE GRADIENT WILL RELAX WITH
WINDS DIMINISHING TO 20 KT OR LESS BY FRI NIGHT. LONG PERIOD NW
SWELL IS PROPAGATING SE ACROSS THE WATERS W OF 105W AND MIXING
WITH LONG PERIOD CROSS-EQUATORIAL SWELL...AND ADDITIONALLY
MIXING WITH LONG PERIOD NE TRADE SWELL ACROSS THE WATERS S OF
THE RIDGE AND W OF 130W. THESE SWELLS WILL GRADUALLY SUBSIDE
OVER THE UPCOMING WEEKEND...HOWEVER SEAS TO 8 FT WILL ARRIVE
ALONG THE NW COAST OF THE BAJA CALIFORNIA PENINSULA ON SUN.

GULF OF PAPAGAYO...EXPECT BRIEF NOCTURNAL DRAINAGE OF ENE 20-25
KT WINDS TONIGHT...AND ON THU AND FRI NIGHTS. GUIDANCE SUGGESTS
A SIGNIFICANT EVENT WILL OCCUR ON SAT AND SUN NIGHTS WITH
THE WESTERN EXTENT NEAR 11N91W...WITH SEAS BUILDING TO 9 FT.

GULF OF TEHUANTEPEC...EXPECT NORTHERLY 20-25 KT WINDS TO SURGE
THROUGH THE ISTHMUS OF TEHUANTEPEC LATE FRI NIGHT...GRADUALLY
INCREASE THROUGHOUT THE DAY ON SAT REACHING MINIMAL GALE FORCE
ON SAT NIGHT THROUGH SUNRISE ON SUN.

$$
NELSON



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.