Hurricane Advisories Hurricane advisories

000
AXPZ20 KNHC 171518
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI FEB 17 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1330 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 02N90W TO 06N104W TO 02N120W TO
02N125W. THE ITCZ EXTENDS FROM 02N125W TO BEYOND 03N140W.
SCATTERED MODERATE CONVECTION LIES WITHIN 120 NM EITHER SIDE OF
AXIS E OF 104W AND WITHIN 210 NM S OF AXIS BETWEEN 107W AND 125W.

...DISCUSSION...

A BROAD UPPER TROUGH EXTENDS FROM A LOW OVER SOUTHERN ARIZONA
NEAR 23N111W THROUGH 20N120W TO ANOTHER WEAKER LOW NEAR 15N140W.
A BELT OF SCATTERED CIRRUS LIES AHEAD OF THE TROUGH AND IS
CENTERED FROM 10N130W THROUGH CENTRAL MEXICO. THE NORTHERN UPPER
LOW WILL MIGRATE EASTWARD INTO TEXAS ON SAT...DISTANCING ITSELF
FROM THE WEAKER LOW OVER WESTERN WATERS. THIS WESTERN LOW WILL
PHASE WITH A NEW TROUGH DROPPING S ALONG THE CALIFORNIA COAST BY
SUN.

AT THE SURFACE...THE RIDGE AXIS EXTENDING FROM 1033 MB HIGH PRES
CENTERED NEAR 35N145W SOUTHEASTWARD TO NEAR 16N105W IS DICTATING
THE PREVAILING FRESH TO STRONG NORTHEASTERLY WINDS ACROSS MUCH
OF THE AREA BETWEEN THE RIDGE AND THE ITCZ/MONSOON TROUGH. THE
AFOREMENTIONED UPPER LOW OVER WESTERN WATERS IS ASSOCIATED WITH
A SURFACE TROUGH FROM 11N117W TO 05N114W. THE 0450 UTC ASCAT
PASS SHOWS FRESH NE WINDS EXTEND EASTWARD TO THE AREA N OF THIS
TROUGH. THIS TROUGH LIES UNDER AN AREA OF BROAD UPPER DIFFLUENCE
ALONG A RIDGE AXIS FROM AN ANTICYCLONE CENTERED NEAR 07S131W TO
A COL NEAR 06N110W. THIS DIFFLUENCE IS ENHANCING SCATTERED
MODERATE CONVECTION FROM 06N TO 13N BETWEEN 107W AND 116W E OF
THE TROUGH.

FRESH NW TO N WINDS LIE JUST N OF THE RIDGE AXIS NEAR THE COAST
OF CABO CORRIENTES MEXICO WHERE THE PRES GRADIENT IS TIGHT
BETWEEN THE RIDGE AND TROUGHING OVER CENTRAL MEXICO ASSOCIATED
WITH THE UPPER LOW CENTERED OVER SOUTHERN ARIZONA. THIS GRADIENT
WILL REMAIN STRONG THROUGH SAT MORNING AND THEN DIMINISH AS THE
REMAINS OF THE LOW ARE EJECTED EASTWARD AND ITS ASSOCIATED COLD
FRONT MOVES INTO THE WESTERN GULF OF MEXICO.

AS THE NEW UPPER TROUGH DROPS S ALONG THE CALIFORNIA COAST EARLY
ON SUN...THE REMNANTS OF ITS ASSOCIATED SURFACE COLD FRONT WILL
MOVE INTO NW WATERS BRINGING FRESH NW TO N WINDS AND NW SWELL TO
12 FEET.

...GAP WINDS...

NE TO E WINDS AT 20 KT THROUGH THE GULF OF PAPAGAYO WILL
CONTINUE UNTIL SAT AFTERNOON WHEN A COLD FRONT MOVES INTO THE
GULF OF MEXICO DISTURBING THE PRES GRADIENT BETWEEN HIGH PRES TO
THE N AND LOWER PRES ALONG THE MONSOON TROUGH TO THE S. THE
STRONGEST WINDS WILL OCCUR DURING EARLY MORNING HOURS WITH THE
AID OF DRAINAGE FLOW.

THE NORTHERLY WINDS OF 20 KT THAT WERE PASSING INTO THE GULF OF
PANAMA YESTERDAY APPEAR TO BE GRADUALLY DIMINISHING...WITH THE
0308 UTC ASCAT PASS ONLY SHOWING ONE BARB OF 20 KT WINDS IN THE
AREA.

LOOKING AHEAD...EXPECT INCREASING WINDS AND SEAS ACROSS THE GULF
OF TEHUANTEPEC BY SUN AFTERNOON AS A STRONG COLD FRONT MOVES
ACROSS THE WESTERN GULF OF MEXICO. THE NORTHERLY WINDS THROUGH
THE PASS INTO THE GULF OF TEHUANTEPEC MAY BRIEFLY REACH GALE
FORCE SUN EVENING.

$$
SCHAUER