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AXPZ20 KNHC 252152
TWDEP

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED NOV 25 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2115 UTC.

...ITCZ...

AXIS ANALYZED FROM 08N78W TO 05N95W TO 07N111W TO 07N115W TO
08N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION NOTED
FROM 05N TO 11N E OF 91W AND ALSO WITHIN 120 NM EITHER SIDE OF
THE ITCZ AXIS W OF 110W.

...DISCUSSION...

AN UPPER ANTICYCLONE NEAR 12N142W HAS A SHORTWAVE RIDGE
EXTENDING N TO A CREST NEAR 36N130W. THE MID AND UPPER LEVELS
ARE DRY N OF 12N W OF 121W. A TROPICAL ANTICYCLONE IS ESTIMATED
NEAR 12N103W WITH VERY DRY AIR AND SUBSIDENCE ALOFT S OF 15N TO
THE EQUATOR BETWEEN 90W AND 105W HELPING TO SUPPRESS ANY
CONVECTION ACROSS THIS AREA AND ALONG THE ITCZ AXIS. AN UPPER
TROUGH EXTENDS FROM NEAR 28N111W TO 17N130W. MOISTURE IS BEING
ADVECTED ALONG AND AHEAD OF THE TROUGH AXIS FROM THE SW UP
ACROSS THE BAJA PENINSULA INTO N CENTRAL MEXICO. CONVERGENT FLOW
ALONG THE ITCZ AXIS S OF THIS TROUGH IS ENHANCING CONVECTION W
OF 110W. A SECOND UPPER LEVEL TROUGH IS SWINGING E ACROSS THE
CENTRAL GULF OF MEXICO. CONVERGENT FLOW BETWEEN THE BASE OF THIS
TROUGH IN THE NW CARIBBEAN AND STRONG ANTICYCLONIC FLOW ACROSS
THE REMAINDER OF THE CARIBBEAN IS ENHANCING CONVECTION OVER
CENTRAL AMERICA AND TO THE W ALONG THE ITCZ IN THE E PACIFIC E
OF 91W.

AT THE SURFACE...HIGH PRESSURE CONTINUES TO DOMINATE THE AREA W
OF 110W. NE TO E TRADES IN THE 20 TO 25 KT RANGE PERSIST ALONG
AND W OF THE RIDGE TO 140W. STRONGER HIGH PRESSURE WILL PASS N
OF THE AREA THU NIGHT THROUGH FRI EXPANDING THE AREA OF NE
TRADES. SEAS OF 8 TO 12 FT ARE ALSO CURRENTLY NOTED SW OF THE
RIDGE WITH NW SWELLS COVERING THE ENTIRE AREA W OF 114W. ANOTHER
SET OF LONG PERIOD NW SWELLS IS EXPECTED TO MOVE INTO THE NW
PORTION OF THE FORECAST AREA BEGINNING LATE TONIGHT WITH SEAS
BUILDING TO 16 FT.

...GAP WINDS...
A 1624 UTC ASCAT PASS CAPTURED NORTHERLY WINDS OF 20 TO 25 KT IN
THE GULF OF TEHUANTEPEC AND WINDS WILL INCREASE TO GALE FORCE
WITHIN THE NEXT 6 HOURS...THEN WILL INCREASE FURTHER TO MINIMAL
STORM FORCE BY EARLY FRI.

STRONG HIGH PRESSURE OVER THE NW CONUS COMBINED WITH A LOW
PRESSURE TROUGH ALONG THE BAJA CALIFORNIA PENINSULA IS
MAINTAINING A TIGHT PRESSURE GRADIENT RESULTING IN STRONG
NORTHERLY WINDS IN THE NORTHERN GULF OF CALIFORNIA. AN 1800 UTC
ASCAT PASS CAPTURED 20 TO 25 KT WINDS IN THE GULF N OF 28N. THE
GRADIENT WILL GRADUALLY DECREASE OVER THE NEXT 24 HOURS
DIMINISHING THE WINDS TO BELOW 20 KT.

EASTERLY TRADES IN THE W CARIBBEAN WILL CONTINUE TO MAINTAIN
SURGES OF 20 TO 25 KT IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO
FOR THE NEXT FEW DAYS.

$$

LEWITSKY




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