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 182147
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU DEC 18 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
2145 UTC.

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

THE MONSOON TROUGH EXTENDS W FROM THE PACIFIC COAST OF COLOMBIA
AT 06N77W TO 06N91W WHERE SCATTEROMETER WINDS INDICATE A
TRANSITION TO AN ITCZ WHICH WIGGLES W BETWEEN 04-06N TO BEYOND
140W. SCATTERED MODERATE CONVECTION IS OBSERVED ALONG THE
MONSOON TROUGH WITHIN 120 NM EITHER SIDE OF A LINE FROM 04.5N77W
TO 07N86W. ISOLATED CLUSTERS OF MODERATE CONVECTION IS NOTED
ELSEWHERE WITHIN 180 NM OF THE MONSOON TROUGH AND ITCZ AXIS.

...DISCUSSION...

AN UPPER LEVEL LONGWAVE TROUGH AND MOVED E OVER THE CENTRAL
PORTION OF THE DISCUSSION AREA WITH ITS MEAN AXIS CURRENTLY
EXTENDING S FROM 32N110W TO A BASE OVER THE DEEP TROPICS AT
10N138W. SHORTWAVE TROUGHS CONTINUE TO PASS THROUGH THE LONGWAVE
PATTERN WITH THE MOST SIGNIFICANT TROUGH CURRENTLY MOVING E INTO
THE FAR NW PORTION OF THE DISCUSSION AREA. SCATTERED MODERATE
CONVECTION IS ENHANCED E OF THE UPPER TROUGH WITHIN 90 NM EITHER
SIDE OF A LINE FROM 07N135W TO 11N121W TO 20N111W. A DENSE
TROPICAL PLUME OF UPPER MOISTURE THAT ORIGINATED FROM ITCZ
CONVECTION BETWEEN 130-170W...CONTINUES TO STREAM NE ACROSS THE
DISCUSSION AREA WITHIN ABOUT 300 NM EITHER SIDE OF A LINE FROM
07N136W TO ACROSS NORTHERN MEXICO...EVENTUALLY TURNING E ACROSS
THE NORTHERN GULF OF MEXICO. DEBRIS MOISTURE FROM THE PREVIOUSLY
DESCRIBED CONVECTIVE CLUSTERS E OF THE UPPER TROUGH IS RE-
ENFORCING THE PLUME.

AT THE LOW LEVELS LONG PERIOD NW SWELL CONTINUES TO MIX WITH
LONG PERIOD SOUTHERLY SWELL ACROSS THE ENTIRE OPEN WATERS WATERS
W OF 100W. A SURFACE RIDGE EXTENDS FROM 28N140W TO 15N98W WITH A
COLD FRONT FORECAST TO PASS E ACROSS THE WATERS N OF THE RIDGE.
ALTHOUGH EXPECTING ONLY A W-NW 10-15 KT WIND SHIFT ALONG THE
FRONT...LARGE POST-FRONTAL NW SWELLS WILL DRIVE COMBINED SEAS UP
TO 17 FT NEAR 30N138W ON FRI. THIS LONG PERIOD NW SWELL WILL
ARRIVE ALONG THE PACIFIC COAST OF THE BAJA PENINSULA IN THE FORM
OF 8-12 FT SEAS AS EARLY AS SAT EVENING...WITH 7-10 FT SEAS
EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE BAJA PENINSULA BY
EARLY SUN.

NE 15-20 KT TRADES ARE OBSERVED ACROSS THE TROPICS BETWEEN THE
ITCZ AND THE RIDGE WITH AN AREA OF EMBEDDED 20-25 KT NE WINDS
ACROSS THE WATERS FROM 10-15N W OF 135W. THE GRADIENT SHOULD
CONTINUE TO TIGHTEN OVER THE NEXT SEVERAL DAYS WITH THE 20-25 KT
CONDITIONS SPREADING BOTH NORTHWARD AND EASTWARD.

GULF OF TEHUANTEPEC...EXPECTING A MAX OF 10-15 KT NOCTURNAL
DRAINAGE FLOW ACROSS THE GULF OF TEHUANTEPEC THROUGH TUE. MODEL
GUIDANCE SUGGESTS THE THE NEXT GALE EVENT WILL OCCUR LATE TUE
NIGHT.

GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES EXPECTED THROUGH
EARLY SUN THEN 10-15 KT DRAINAGE EARLY NEXT WEEK.

GULF OF CALIFORNIA...10-15 KT NW WINDS ARE EXPECTED TO GRADUALLY
INCREASE TO 15-20 KT LATE TONIGHT BY EARLY FRI...AND THEN CONTINUE
THROUGH SUN NIGHT BEFORE DIMINISHING TO 15 KT ON MON.

$$
NELSON



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