Tropical Weather Discussion
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000
AXPZ20 KNHC 212151
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN DEC 21 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 SW FROM THE PACIFIC COAST OF COLOMBIA
AT 07N78W TO 05N81W...THEN TURNS NW TO 07N86W...THEN SW AGAIN TO
06N92W TO 07N97W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION
TO AN ITCZ WHICH CONTINUES NW TO AN EMBEDDED TROUGH AT 08N109W WITH
THE ITCZ THEN CONTINUING W TO BEYOND 08N140W. SCATTERED MODERATE
ISOLATED STRONG CONVECTION IS OBSERVED ALONG THE MONSOON TROUGH
FROM 04-09N TO THE E OF 83W AND ALSO ALONG THE ITCZ WITHIN 90 NM
EITHER SIDE OF A LINE FROM 04N110W TO 07N120W TO 09N140W. THE
EMBEDDED TROUGH EXTENDS FROM 05N110W TO 13N109W WITH SCATTERED
MODERATE CONVECTION NOTED WITHIN 30 NM EITHER SIDE OF A LINE FROM
10N112W TO 16N103W.

...DISCUSSION...

A POSITIVE TILT UPPER LEVEL TROUGH EXTENDS FROM 32N98W ACROSS
CENTRAL MEXICO TO BASE AT 15N122W. EVAPORATING UPPER MOISTURE IS
SPREADING SE INTO THE THE UPPER TROUGH ACROSS THE SOUTHERN BAJA
CALIFORNIA PENINSULA AND ACROSS THE THE SOUTHERN GULF OF
CALIFORNIA. ANOTHER BAND OF UPPER MOISTURE HAS MOVED S ACROSS
THE DISCUSSION AREA N OF 29N E OF 125W...AND WILL CONTINUE S
ACROSS THE NORTHERN BAJA PENINSULA AND THE NORTHERN GULF OF
CALIFORNIA TONIGHT. A PLUME OF UPPER MOISTURE...ORIGINATING FROM
ITCZ CONVECTION BETWEEN 126-167W...CONTINUES TO STREAM E ACROSS
THE DISCUSSION AREA WITHIN 300 NM EITHER SIDE OF A LINE FROM
11N140W TO 10N117W...THEN THE PLUME TURNS NE IN RESPONSE TO THE
UPPER TROUGH WITHIN 300 NM OF LINE FROM 13N114W TO OVER THE
PACIFIC COAST OF MEXICO AT 18N101W...THEN NARROWS AS IT
CONTINUES NE ACROSS THE CENTRAL GULF OF MEXICO...THEN TURNING NE
AND FANNING OUT ACROSS THE ENTIRE SE CONUS.

A 1031 MB SURFACE HIGH IS ANALYZED AT 34N133W WITH A RIDGE
EXTENDING SE TO 17N105W. NE-E 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 WITH SEAS OF 8-14 FT ACROSS THE
WATERS FROM 09-19N W OF 120W. THE GRADIENT IS ALREADY RELAXING
AND THE AREA OF 20-25 KT CONDITIONS WILL SHRINK TONIGHT AND MON
WITH WINDS DIMINISHED BELOW 20 KT ACROSS THE TROPICS ON TUE. THE
GRADIENT WILL SUPPORT AN AREA OF 20-25 KT N WINDS ACROSS THE SUB-
TROPICAL WATERS N OF 29N BETWEEN 119-125W THROUGH TUE MORNING
BEFORE DIMINISHING BELOW 20 KT. OTHERWISE...LONG PERIOD NW SWELL
HAS SPREAD E ACROSS THE DISCUSSION AREA W OF 110W...RESULTING IN
COMBINED SEAS OF 8-14 FT. THIS LONG PERIOD NW SWELL WILL
GRADUALLY SUBSIDE THROUGH THE MIDDLE OF THE WEEK. EXPECT 5-8 FT
CONDITIONS ALONG THE ENTIRE PACIFIC COAST OF THE BAJA PENINSULA
ON MON AND MON NIGHT. GUIDANCE IS SUGGESTING NE WINDS WILL
INCREASE TO 20-30 KT ALONG THE PACIFIC COAST OF THE BAJA
PENINSULA NEAR 29N ON TUE...SPREAD SW TO NEAR 27N117W ON TUE
NIGHT...THEN DIMINISH TO 15 KT BY LATE WED.

GULF OF TEHUANTEPEC...EXPECTING A MAX OF 10-15 KT NOCTURNAL
DRAINAGE FLOW ACROSS THE GULF OF TEHUANTEPEC TONIGHT AND LIGHT
WINDS EXPECTED ON MON NIGHT. MODEL GUIDANCE IS CONSISTENT THAT
THE DRAINAGE FLOW WILL INCREASE TO 20-30 KT EARLY WED MORNING...
THEN RAPIDLY INCREASE TO STRONG GALE FORCE WED AFTERNOON...AND
FURTHER INCREASE TO NEAR STORM STRENGTH WED NIGHT. EXPECT THE
GALE EVENT TO END ON THU NIGHT.

GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES EXPECTED THROUGH
EARLY TUE...THEN ONLY 10-15 KT DRAINAGE FLOW ON TUE NIGHT.
GUIDANCE SUGGESTS BRIEF 15-20 KT CONDITIONS ON WED NIGHT...WITH
A SIGNIFICANT EVENT OF 20-25 KT EVENT ON THU NIGHT
WHICH WILL EXTEND AS FAR SW AS 08N92W LATE FRI.

GULF OF CALIFORNIA...15-20 KT NW WINDS ARE EXPECTED TONIGHT
THROUGH MON NIGHT EXCEPT 10-15 KT CONDITIONS BRIEFLY LATE MON.
THE GRADIENT WILL TIGHTEN EARLY TUE WITH THE NW FLOW INCREASING
TO 20-25 KT ACROSS THE NORTHERN GULF WATERS TUE MORNING...WITH
20-30 KT CONDITIONS SPREADING S ACROSS THE ENTIRE GULF OF
CALIFORNIA BY TUE EVENING. SEAS WILL BUILD TO 9 FT IN LONG FETCH
WATERS NEAR 29N BY TUE EVENING. THE GRADIENT SHOULD RELAX ON WED
WITH 15-20 KT FLOW ON WED NIGHT AND ONLY 10-15 KT NW FLOW ON
THU.

$$
NELSON


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