Tropical Weather Discussion
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993
AXPZ20 KNHC 130315
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT FEB 13 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
0315 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...GALE FORCE NORTHERLY WINDS...
WITH SEAS TO 17 FT...ARE EXPECTED TO PERSIST THROUGH SUN
MORNING. THE N WINDS WILL GRADUALLY DIMINISH TO 20 KT OR LESS ON
MON MORNING. THE RESULTANT SWELL CONTINUES TO PROPAGATE SE
THROUGH SW...MERGING WITH ENE SWELL GENERATED FROM PULSING
STRONG WINDS IN GULFS OF FONSECA AND PAPAGAYO...MERGING WITH
LONG PERIOD CROSS-EQUATORIAL SW SWELL AND ALSO MERGING WITH LONG
PERIOD NW SWELL. SEAS 12 FT OR GREATER ARE EXPECTED TO SPREAD SW
TO NEAR 06N107W ON SUN...WITH SEAS 8 FT OR GREATER REACHING THE
EQUATOR BETWEEN 95-110W. SEE LATEST NWS HIGH SEAS FORECAST UNDER
AWIPS/ WMO HEADERS MIAHSFEP2/FZPN03 KNHC FOR MORE DETAILS.

EPAC GALE WARNING....A COUPLE OF LOW LEVEL TROUGHS HAVE
DEVELOPED IN THE TROPICAL PACIFIC. THE EASTERNMOST TROUGH
EXTENDS FROM 06N117W TO 12N115W. THE WESTERN TROUGH EXTENDS FROM
05N129W TO 11N128W. THE ARRAY OF MODEL GUIDANCE AGREE ON THE
PRESSURE GRADIENT TIGHTENING ACROSS THE AREA W OF 120W. USING A
BLEND OF MODEL GUIDANCE LEADS TO SOLUTION OF THE WESTERN TROUGH
REACHING FROM 08N132W TO 16N125W LATE SAT WITH NE-E WINDS
INCREASING TO 20-30 KT ACROSS THE WATERS N OF 12N WITHIN 210 NM
E AND WITHIN 420 NM W OF THE TROUGH AXIS...WITH AN EMBEDDED BAND
OF 30-35 KT MINIMAL GALE FORCE WINDS WITHIN 240 NM W OF THE
TROUGH. THE GRADIENT WILL SUPPORT FRESH TO STRONG NE WINDS
ELSEWHERE N OF 10N W OF 120W THROUGH SUN. THE GALE CONDITIONS
WILL PERSIST W OF THE TROUGH THROUGH SUN MORNING.

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

TWO LOW LEVELS TROUGH HAVE DEVELOPED. THE EASTERN TROUGH EXTENDS
FROM 06N117W TO 12N115W WITH SCATTERED MODERATE ISOLATED STRONG
CONVECTION WITHIN 210 NM OF TROUGH AXIS. THE WESTERN TROUGH
EXTENDS FROM 05N129W TO 11N128W WITH SCATTERED MODERATE ISOLATED
STRONG CONVECTION OBSERVED TO THE N OF 08N WITHIN 270 NM E AND
WITHIN 90 NM W OF TROUGH AXIS. SCATTEROMETER WINDS INDICATE THAT
THE ITCZ FORMS AT 02N89W AND WIGGLES W TO BEYOND 03N140W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90
NM EITHER SIDE OF A LINE FROM 04N90W TO 07N107W.

...DISCUSSION...

ELSEWHERE N OF 15N E OF 120W...A WEAK SURFACE RIDGE EXTENDS SE
FROM 27N120W TO 19N106W. THE GRADIENT WILL SUPPORT LIGHT TO
MODERATE N-NE FLOW ACROSS THE OPEN PACIFIC WATERS BETWEEN 105-
120W INTO EARLY NEXT WEEK. COMBINED SEAS OF 7-10 FT IN NW SWELL
HAVE REACHED THE OPEN PAC WATERS N OF 27N. THESE LARGE SEAS WILL
REACH THE SOUTHERN PORTION OF BAJA EARLY SAT AND PERSIST THROUGH
SUN...THEN SUBSIDE FROM THE N ON MON. LIGHT AND VARIABLE WINDS
ARE OBSERVED BETWEEN 97-106W WITH THE PREVIOUSLY DESCRIBED GALE
EVENT OCCURRING ACROSS THE WATERS TO THE E OF 97W. MODERATE NW
WINDS ARE EXPECTED ACROSS THE GULF OF CALIFORNIA THROUGH SUN
MORNING...INCREASING TO FRESH ON SUN AFTERNOON ACROSS THE
CENTRAL GULF WATERS AND SPREADING N ACROSS THE WATERS N OF 30N
ON SUN NIGHT. STRONG NW WINDS EXPECTED ACROSS THE GULF OF
CALIFORNIA ON MON AFTERNOON.

S OF 15N E OF 110W...PATCHES OF STRONG NE WINDS WILL DEVELOP
TONIGHT AND AGAIN ON SAT ACROSS THE WATERS N OF 12N E OF 89W...
INCLUDING THE GULF OF FONSECA...WITH SEAS BUILDING TO ONLY 9 FT
IN THE LIMITED FETCH. NE 20-30 KT SURGES WILL CONTINUE ACROSS
AND DOWNSTREAM OF THE GULF OF PAPAGAYO THROUGH SUN MORNING AND
EXTEND AS FAR SW AS 07N93W. EXPECT THE NE FLOW TO DIMINISH TO 15-
20 KT DURING THE AFTERNOONS BEGINNING ON SUN...THEN INCREASE TO
20-25 KT AGAIN EACH NIGHT. MODERATE TO FRESH N WINDS ARE
EXPECTED TODAY ACROSS THE TROPICAL WATERS N OF ABOUT 04N AND W
OF ABOUT 87W. PULSES OF FRESH TO STRONG NORTHERLY WINDS WILL
SPREAD S FROM THE GULF OF PANAMA TO ALONG ABOUT 04N EACH NIGHT
THROUGH THROUGH SUN NIGHT WITH SEAS BUILDING TO ABOUT 10 FT NEAR
06N81W.

$$
NELSON



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