631
AXPZ20 KNHC 272201
TWDEP
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI NOV 27 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 ALONG 07N78W TO 06.5N96W TO 06N99W TO 09N119W TO
08N123W TO 08N140W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION WAS NOTED WITHIN 120 NM S OF THE AXIS BETWEEN 85W AND
88W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60 NM EITHER
SIDE OF THE AXIS BETWEEN 88W TO 95W AND WITHIN 120 NM N OF THE
AXIS BETWEEN 130W AND 140W. NUMEROUS MODERATE AND SCATTERED
STRONG CONVECTION WAS NOTED WITHIN 210 NM S OF THE AXIS AND 120
NM N OF THE AXIS BETWEEN 114W AND 130W.
..DISCUSSION
UPPER LEVEL TROUGH EXTENDS FROM 35N114W TO 29N138W WITH DEEP SW
MOIST FLOW MOVING UP ALONG THE TROUGH AXIS FROM JUST S OF THE
HAWAIIAN ISLANDS UP INTO CALIFORNIA. N OF THIS TROUGH A LARGE
UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 39N130W WITH DRY AND
STABLE AIR BUILDING IN BEHIND THE TROUGH. AT THE SURFACE A 1037
MB HIGH PRES IS CENTERED NEAR 38N138W WITH A RIDGE AXIS
EXTENDING FROM THE HIGH TO NEAR 22.5N118.5W. A TIGHT PRES
GRADIENT IS IN PLACE BETWEEN THE HIGH AND ITCZ W OF 122W AND A
1900 UTC ASCAT PASS AND A 1500 UTC WINDSAT PASS BOTH INDICATED
20 TO 25 KT TRADE WINDS ACROSS THAT AREA. MEANWHILE LARGE LONG
PERIOD NW SWELL UP TO 16 FT CONTINUES TO PROPAGATE THROUGH THE
DISCUSSION AREA W OF 115W. THESE CONDITIONS WILL CONTINUE FOR
THE NEXT FEW DAYS. A SECOND LONG WAVE AND DEEP LAYER TROUGH
EXTENDS FROM S TEXAS TO NEAR 15N118W WITH DRY AND STABLE AIR
ALOFT NW OF THE TROUGH SUPPRESSING ANY CONVECTION.
ELSEWHERE...A 1008 MB LOW IS CENTERED NEAR 06N97W WITH A TROUGH
FLANKING THE LOW FROM 02N98W TO 11N95W. THIS FEATURE IS
PRODUCING SCATTERED MODERATE CONVECTION AND WINDS OF 20 TO 25
KT...AND WILL CONTINUE TO MOVE TO THE W AROUND 10 KT DURING THE
NEXT 48 HOURS. ANOTHER TROUGH IS LOCATED FROM 12N122W TO 19N116W
WITH 20 TO 25 KT NE WINDS REALIZED NW OF THE TROUGH. THIS
FEATURE WILL DRIFT TO THE N-NE DURING THE NEXT 48 HOURS. LATEST
GFS GUIDANCE EVOLVES THE TROUGH INTO A CLOSED AREA OF LOW PRES BY
48 HOURS HOWEVER THE ECMWF KEEPS IT AS A MUCH WEAKER SYSTEM/
TROUGH. WILL FOLLOW A BLEND OF THESE TWO DIFFERING SOLUTIONS FOR
NOW.
..GAP WINDS
STRONG HIGH PRES OF 1026 MB HAS BECOME ESTABLISHED ACROSS THE
GULF OF MEXICO IN WAKE OF A SURFACE COLD FRONT WHICH HAS NOW
MOVED INTO THE NW CARIBBEAN. COLD AIR CONTINUES TO BE CHANNELED
FROM THE SOUTHERN GULF OF MEXICO ACROSS THE ISTHMUS OF
TEHAUNTEPEC AND OVER THE GULF OF TEHUANTEPEC AND DOWNSTREAM
WATERS. STORM FORCE WINDS WILL DIMINISH TO GALE FORCE IN THE
NEXT 6 HOURS...AND WILL FURTHER DIMINISH TO LESS THAN 20 KT IN
LESS THAN 48 HOURS WITH THE THERMAL GRADIENT DIMINISHING AS THE
AIRMASS BECOMES MODIFIED.
EASTERLY TRADES IN THE W CARIBBEAN WILL CONTINUE TO FUNNEL WINDS
THROUGH GULF OF PAPAGAYO AND DOWNSTREAM WATERS TO NEAR 91W
THROUGH SUN TO MAINTAIN A FRESH TO STRONG BREEZE.
LEWITSKY
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