Tropical Weather Discussion
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000
AXPZ20 KNHC 281006
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED JAN 28 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0945 UTC.

...SPECIAL FEATURES...
GULF OF TEHUANTEPEC GALE WARNING...A PERSISTENT TIGHT PRESSURE
GRADIENT ACROSS SOUTHEASTERN MEXICO IS PRODUCING A LONG DURATION
EVENT OF N TO NE 30-45 KT WINDS THROUGH THE GULF OF TEHUANTEPEC.
SHIP "C6FR3" NEAR 15N94W REPORTED NE WINDS AT 43 KT AT 04 AND 06
UTC. THE GALE WINDS HAVE RAISED THE SEAS IN THE GULF TO THE
RANGE OF 11-18 FT. NE SWELLS THAT HAVE PROPAGATED DOWNSTREAM
FROM THIS EVENT OVER THE PAST FEW DAYS ARE COMBINING WITH LONG
PERIOD NW SWELLS. THE COMBINATION OF THESE SWELLS IS RESULTING
IN A LARGE AREA OF SEAS TO 9 FT FROM 04N TO 14N BETWEEN 91W AND
105W...ALSO FROM 04N TO 12N BETWEEN 105W AND 110W AND FROM 07N
TO 19N BETWEEN 110W AND 124W. FRESH TRADE WINDS OVER THE WESTERN
PORTION OF THIS AREA ARE ALSO HELPING TO MAINTAIN THE SEAS HIGH.
MOST RECENT SEA SURFACE TEMPERATURE ANALYSIS REVEALS A COOL
POCKET OF WATERS OVER A PORTION OF THE GULF AS WELL AS
DOWNSTREAM FROM THE GULF TO NEAR 13N BETWEEN 94W-97W DUE TO
UPWELLING EFFECTS.

HIGH PRES CENTERED OVER THE WESTERN GULF OF MEXICO WITH THE
ASSOCIATED CULPRIT TIGHT PRES RIDGING STRETCHING SEWD ACROSS
SOUTHEASTERN MEXICO IS FORECAST TO GRADUALLY WEAKEN THROUGH
THU. THE GALE WINDS ARE EXPECTED TO DECREASE SLIGHTLY THROUGH
TONIGHT...AND TO MINIMAL GALE FORCE BY EARLY THU AFTERNOON WITH
SEAS SUBSIDING TO AROUND 14 FT AND TO 12 FT THU NIGHT. THE WINDS
THEN INCREASE SOME THU NIGHT AND INTO EARLY FRI AS THE RIDGING
BECOMES REINFORCED BY ANOTHER RIDGE THAT BUILDS SWD OVER THE FAR
WESTERN GULF AND EASTERN MEXICO TERRAIN. SEAS IN THE GULF ARE
FORECAST BY THE TAFB/NWPS GUIDANCE TO BUILD TO BACK TO 14 FT ON
FRI.

GULF OF PAPAGAYO GALE WARNING...A TIGHTENING PRES GRADIENT
BEHIND A SHEAR LINE IN THE WESTERN CARIBBEAN SEA N OF 10N WILL
ALLOW FOR NE WINDS FUNNELING THROUGH THE GULF OF PAPAGAYO TO
INCREASE TO MINIMAL GALE FORCE BY DAYBREAK THIS MORNING. WINDS
WILL DIMINISH BELOW GALE FORCE DURING THE DAYTIME HOURS AND
PULSE BACK TO GALE FORCE WITH THE ASSISTANCE OF DRAINAGE FLOW
OFF THE MOUNTAINS IN THE LATE NIGHT AND EARLY MORNING HOURS
THROUGH THU. SEAS IN AND NEAR THE GULF ARE FORECAST TO BUILD TO
THE RANGE OF 8-12 FT THIS AFTERNOON AND THROUGH THU AFTERNOON
BEFORE SUBSIDING TO AROUND 9 FT BY LATE THU. NE SWELLS FROM
PAPAGAYO WILL CONTINUE TO MERGE WITH THE SWELL FROM THE GULF OF
TEHUANTEPEC THROUGH THE FORECAST PERIOD.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 02N78W TO 06N85W TO 05N94W
WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO THE ITCZ AXIS
EXTENDING TO 04N105W TO 07N114W TO 08N125W AND TO 08N140W. NO
SIGNIFICANT DEEP CONVECTION IS NOTED ALONG OR NEAR THE MONSOON
TROUGH AND ITCZ AXIS.

...DISCUSSION...
A SLOW MOVING...NEGATIVELY TILTED UPPER LEVEL TROUGH IS THE MAIN
FEATURE NOTED. IT STRETCHES FROM NEAR 32N130W TO 23N129W TO
16N127W AND TO 09N122W. A SOUTHERLY JET STREAM BRANCH ON THE E
SIDE OF THE TROUGH HAS MAX WINDS OF 80-100 KT. THIS IS HELPING
TO ADVECT ABUNDANT UPPER MOISTURE...MAINLY IN THE FORM OF BROKEN
TO OVERCAST MID AND UPPER CLOUDS NNE ACROSS SOUTHERN BAJA
CALIFORNIA AND W CENTRAL MEXICO. UNDERNEATH THIS MOISTURE
...SCATTERED SHOWERS AND ISOLATED TSTMS ARE POSSIBLE FROM 10N-
28N E OF THE TROUGH TO 110W. A SURFACE REFLECTION OF THIS TROUGH
IS ANALYZED FROM 16N122W TO 11N123W. LIGHTNING DENSITY DATA
INDICATES MULTIPLE LIGHTNING STRIKES WITHIN THE MENTIONED
ACTIVITY FROM 13N-18N BETWEEN 119W-123W. THE DEEP LAYERED TROUGH
WILL GRADUALLY SHIFT EASTWARD THROUGH THE NEXT 24N-48 HRS WITH
THE CLOUDINESS AND MOISTURE TO ITS E GRADUALLY SPREADING OVER
MUCH OF BAJA CALIFORNIA AND THE WESTERN PORTION OF MEXICO N OF
ABOUT 18N. ELSEWHERE...HIGH PRES OF 1023 MB IS CENTERED NEAR
35N124W MOVING NW 10 KT. A RIDGE EXTENDS FROM THE HIGH SE TO
15N118W AND TO NEAR 18N116W. A WEAK TROUGH EXTENDS FROM 16N135W
TO 15N138W.

GAP WINDS...
SEE SPECIAL FEATURES ABOVE FOR GULFS OF TEHUANTEPEC AND
PAPAGAYO GALE EVENTS.

GULF OF PANAMA...THE TIGHTENING PRES GRADIENT OVER THE WESTERN
CARIBBEAN SEA IS RESULTING IN STRONG N WINDS TO FUNNEL SWD
THROUGH THE GULF OF PANAMA WITH SEAS TO 8 FT. THESE WINDS ARE
FORECAST TO REACH AS FAR S AS 04N BY LATE TONIGHT WITH SEAS
BUILDING TO 10 FT...AND LAST THROUGH WED AFTERNOON BEFORE
SUBSIDING SLIGHTLY THU NIGHT.

GULF OF CALIFORNIA...THE PRES DIFFERENCE BETWEEN A TROUGH JUST W
OF MEXICO ALONG 106W FROM 16N-19N AND HIGH PRES RIDGING JUST W
OF BAJA CALIFORNIA WILL INDUCE FRESH TO STRONG NW-N WINDS
OFFSHORE OF THE SE TIP OF THE BAJA CALIFORNIA PENINSULA BY
DAYBREAK THIS MORNING WITH SEAS TO 8 FT. THE GRADIENT WILL
WEAKEN ENOUGH TO ALLOW THESE WINDS TO DIMINISH TO 20 KT OR LESS
BY EARLY THU AFTERNOON...THEN INCREASE AGAIN FROM 22N-25N
BETWEEN 108W-110W BY LATE THU NIGHT AS RIDGING ACROSS THE
EASTERN PACIFIC WATERS STRENGTHENS.

$$
AGUIRRE


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