000
AXPZ20 KNHC 101000
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT APR 10 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...ITCZ...

AXIS IS CENTERED ALONG 6N78W 8N85W 4N100W 6N124W 2N133W 4N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF THE AXIS 
BETWEEN 113W-124W. SCATTERED MODERATE CONVECTION IS WITHIN 120 
NM S OF THE AXIS BETWEEN 87W-90W...AND 101W-104W.

...DISCUSSION...

A MID/UPPER LEVEL SHORTWAVE TROUGH HAS RECENTLY EXITED THE AREA
TO THE SW UNITED STATES. WLY FLOW JUST ABOUT THE ENTIRE AREA N
OF 19N...EXCEPT FOR THE NW PORTION OF THE AREA WHERE THE SRN
PORTION OF A DEEP LAYER TROUGH ENTERS CROSSES 30N AT 132W...AND
REACHES TO W OF THE AREA AT 27N140W. THE TROUGH IS FORECAST TO 
RAPIDLY MOVE E TOWARDS THE FAR NE PORTION OF THE AREA BY SUN 
NIGHT. IT WILL INTENSIFY AS IT GETS REINFORCED BY A LARGE CLOSED 
UPPER LOW THAT IS FORECAST TO DROP S FROM THE GULF OF ALASKA
...BUT STAY N OF THE AREA AS IT TURNS ENE AND TAKES AIM TOWARD
THE U.S. W COAST OVER THE WEEKEND. SATELLITE WATER VAPOR IMAGERY 
INDICATES AN AREA OF MODERATE SUBSIDENCE WITH ASSOCIATED DRY AND 
STABLE CONDITIONS FROM 19N TO 27N.

S OF 19N...A BROAD MID/UPPER LEVEL RIDGING IS NOTED GENERALLY 
TO THE W OF 95W WITH AN ASSOCIATED ANTICYCLONE NEAR 8N124W. A
SUBTROPICAL JET STREAM BRANCH ENTERS THE AREA THROUGH 18N140W 
AND CONTINUES ENE TO 19N130W TO 19N120W...THEN NE TO ACROSS
CENTRAL MEXICO.THE JET IS TRANSPORTING UPPER LEVEL MOISTURE IN 
THE FORM OF SCATTERED TO BROKEN CIRRUS CLOUDS S OF THE JET TO 
EWD ACROSS THE AREA TO OVER CENTRAL MEXICO.

ACROSS THE DEEP TROPICS...CONVECTION REMAINS VERY ACTIVE ALONG 
THE ITCZ W OF 110W AND IS HELPING TO MAINTAIN THE ABOVE AREA
OF BROAD MID/UPPER LEVEL RIDGING. WITH UPPER LEVEL DIFFLUENCE
CONTINUING TO HOLD S OF THE RIDGE...EXPECT CONVECTION NEAR AND 
ALONG THE ITCZ TO REMAIN ACTIVE W OF ABOUT 110W THROUGH THE NEXT 
48 HRS. 

OVER THE FAR EASTERN PART OF THE AREA...A VERY NARROW MID/UPPER
LEVEL TROUGH AXIS STRENGTHS FROM WRN HONDURAS SW TO 11N95W. ONLY
ISOLATED SHOWERS ARE NOTED NEAR THE TROUGH AS SUBSIDENCE ALOFT 
SUPPRESS CONVECTION FROM DEVELOPING WITH IT. A MID/UPPER LEVEL
RIDGE IS TO THE SE OF THE TROUGH ALONG 7N EXTENDING EWD TO ACROSS
S AMERICA. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
ACTIVE UNDER THE RIDGE ALONG THE ITCZ E OF 79W TO INLAND THE
COLOMBIAN COAST.

AT THE SURFACE...A RIDGE STRETCHES INTO THE AREA FROM A 1022 MB 
HIGH CENTERED AT 30N135W SE TO NEAR 21N122W. HIGH PRES COVERS
THE AREA N OF 14N AND W OF 121W. THE PRES GRADIENT BETWEEN THE 
RIDGE AND LOWER PRES ASSOCIATED WITH THE ITCZ HAS WEAKENED
DURING THE PAST 24 HOURS...WITH ONLY A SMALL AREA OF NE WINDS OF 
20 KT REMAINING FROM 4N-15N W OF 131W. A TIGHT PRES GRADIENT 
REMAINS BETWEEN THE AFOREMENTIONED RIDGE AND LOWER PRES OVER THE 
SW U.S. RESULTING IN A LARGE AREA OF NW 20-30 KT WINDS JUST N OF 
THE AREA E OF 128W. THE HIGH IS FORECAST TO SLIDE SE AND 
SLIGHTLY WEAKEN THROUGH THE NEXT 24-48 HRS ALLOWING FOR THE
PRES GRADIENT TO COMPLETELY RELAX AND WINDS TO DIMINISH.
WITH THE HIGH MOVING SE...IT CURRENTLY APPEARS THAT A COLD
FRONT ASSOCIATED WITH THE TROUGH AND CLOSED MENTIONED IN THE 
FIRST PARAGRAPH WILL PUSH INTO THE NW SECTION OF THE AREA 
IN 24 HRS AT WHICH TIME IT WILL EXTEND FROM NEAR 30N134W TO
25N140W...THEN WEAKEN AS IT REACHES FROM NEAR 30N123W TO 21N140W
IN ABOUT 48 HRS. WINDS AHEAD AND BEHIND THE FRONT WILL INCREASE 
TO 20-25 KT...BUT QUICKLY DIMINISH TO 20 KT IN 48 HRS AS PRES 
GRADIENT WEAKENS AS WEAK HIGH PRES SETTLES IN OVER THE AREA.

GAP WINDS...
FRESH TO STRONG TRADES OVER THE CARIBBEAN SEA CONTINUE TO FUNNEL 
W ACROSS THE GULF OF PAPAGAYO RESULTING IN NE 20-30 KT WINDS
AS SUPPORTED BY A HIGH RESOLUTION ASCAT PASS FROM 0335 UTC LAST
NIGHT. MODEL GUIDANCE SHOWS THAT THESE WINDS WILL CHANGE LITTLE
THROUGH THE NEXT 24 HRS...THEN DECREASE TO 20 KT IN 48 HRS AS 
THE WRN CARIBBEAN TRADES WEAKEN QUITE SIGNIFICANTLY.
  
A TIGHT PRES GRADIENT ANALYZED ACROSS SE MEXICO IS ALLOWING
FOR N TO NE WINDS IN THE RANGE OF 20-25 KT TO FUNNEL S THROUGH 
THE GULF OF TEHUANTEPEC WITHIN 45 NM EITHER SIDE OF A LINE FROM 
16N94.5W TO 14N95W TO 12N96W. MODEL GUIDANCE INDICATES THAT THE 
N TO NE WINDS WILL CONTINUE THROUGH THE NEXT 24 HRS AT THESE
SPEEDS...BUT DIMINISH IN AREAL COVERAGE AND BE CONFINED TO 
N OF 14N BETWEEN 94W AND 96W WITH SEAS TO 8 FT. BY 42 HRS
...CONDITIONS DIMINISH THROUGH THE GULF. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
AGUIRRE