East Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 052203
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN JUL 05 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 
2145 UTC.

...SPECIAL FEATURE...

AN AREA OF LOW PRESSURE CENTERED NEAR 16N110W...OR ABOUT 375 
MILES SW OF MANZANILLO MEXICO HAS ONLY SLIGHT IMPROVEMENT TO ITS 
CLOUD STRUCTURE DURING THE COURSE OF THE DAY. LATEST SATELLITE 
IMAGERY REVEALS A BAND REMOVED FROM THE CENTER CONSISTING OF 
SCATTERED STRONG CONVECTION WITHIN 30 NM EITHER SIDE OF A LINE 
FROM 14N109W TO 16N107W...AND WITHIN 45 NM EITHER SIDE OF LINE 
FROM 16N07W TO 18N108W. SCATTERED STRONG CONVECTION IN SMALL 
CLUSTERS IS WITHIN 75 NM S OF AND 120 NM W OF THE CENTER. 
SCATTEROMETER DATA FROM THIS MORNING DEPICTED THE A LARGE SWATH 
OF 20-30 KT WINDS WITHIN ABOUT 300 NM OF THE LOW IN THE NE 
QUADRANT. THE LOW IS FORECAST TO POSSIBLY BECOME A TROPICAL 
CYCLONE AS IT MOVES TO NEAR 18N114W IN 24 HRS...AND TO NEAR 
18N119W IN 48 HRS. WILL KEEP MENTION OF 20-30 KT IN THE NE 
QUADRANT THROUGH THE NEXT 48 HRS. WILL BUILD HIGHER SEAS IN THE 
FORECAST (IN THE 9-14 FT RANGE) THAN WHAT IS INDICATED BY THE 
WAVEWATCH GUIDANCE...SEAS MAY EVEN BE AT HIGHER LEVELS IF THE 
LOW INTENSIFIES MUCH SOONER THAN ANTICIPATED.

...TROPICAL WAVES...

TROPICAL WAVE HAS JUST ENTERED THE EXTREME ERN PACIFIC...AND IS  
ALONG 80W N OF 03N MOVING W AT 18 KT. THE WAVE REMAINS UNDER
AN UPPER DIFFLUENT ZONE INDUCED BY AN UPPER LOW OVER THE NW 
CARIBBEAN...AND AN UPPER ANTICYCLONE OVER NICARAGUA. THIS IS
SUPPORTING SCATTERED STRONG CONVECTION ALONG THE COAST OF NRN
COSTA RICA. ISOLATED SHOWERS ARE WITHIN 120 NM W OF THE WAVE.
LOW-LEVEL SPEED CONVERGENCE ASSOCIATED WITH A SHORT-LIVED 
PAPAGAYO GAP WIND EVENT MAY BE CONTRIBUTING TO SCATTERED
MODERATE CONVECTION NW OF THE WAVE NEAR THE COAST OF COSTA
RICA.

TROPICAL WAVE ALONG 99W FROM 3N TO 15N IS MOVING W 15-20 KT. 
THIS POSITION IS BASED ON CONTINUITY AS THERE IS NOT ANY OBVIOUS 
EVIDENCE OF THE FEATURE IN THE AVAILABLE DATA. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N83W 07N100W 16N109W 10N120W 9N130W
7N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN
180 NM S OF THE AXIS BETWEEN 83W-94W...AND ALSO FROM 7N-11N 
BETWEEN 99W-101W.

...DISCUSSION...

A WELL PRONOUNCED ELONGATED NE TO SW MID/UPPER LEVEL ANTICYCLONE 
EXTENDS FROM FAR SW TEXAS SW TO ACROSS CENTRAL BAJA CALIFORNIA 
TO 26N125W TO 25N132W TO W OF THE AREA AT 21N140W. TO THE W OF 
THE RIDGE...A LARGE DEEP LAYER TROUGH IS OBSERVED WELL W OF THE 
REGION. SW UPPER LEVEL FLOW BETWEEN THE TROUGH AND THE RIDGE 
CONTINUES TO ADVECT DEEP TROPICAL UPPER LEVEL MOSITURE NEWD FROM 
THE CENTRAL PACIFIC INTO THE FAR NW CORNER OF THE AREA. 
OTHERWISE...SATELLITE WATER VAPOR IMAGERY SHOWS THAT THE VAST 
MAJORITY OF THE DISCUSSION AREA W OF A LINE FROM CENTRAL BAJA 
CALIFORNIA TO 19N124W TO 9N134W IS UNDER MODERATE SUBSIDENCE 
MAINTAINING STABLE ENVIRONMENTAL CONDITIONS AS INDICATED BY THE 
PRESENCE OF PATCHES OF SCATTERED TO BROKEN STRATOCUMULUS CLOUDS 
MOVING SW AROUND THE ERN PERIPHERY OF HIGH PRES PRESENT N OF 17N 
W OF 118W WITH THE HIGH CENTER OF 1022 MB ANALYZED NEAR 29N131W.

OVER THE REMAINDER OF THE AREA ABUNDANT UPPER LEVEL MOISTURE
IS OBSERVED ON SATELLITE IMAGERY...PRIMARILY ATTRIBUTED TO 
THE WESTWARD TRANSFER OF UPPER LEVEL MOSITURE UNDER BY UPPER
LEVEL ELY WINDS ON THE SRN PERIPHERY OF THE ABOVE DESCRIBED
UPPER LEVEL ANTICYCLONE. THE MOISTURE IS ALSO ENHANCED BY 
DEBRIS CLOUDINESS FROM ITCZ CONVECTION E OF 110W AS WELL AS
THAT ASSOCIATED WITH THE LOW NEAR 16N110W.

THE COMBINATION OF HIGH PRES AS STATED ABOVE AND A SURFACE 
TROUGH THAT EXTENDS FROM 6N135W TO 12N133W IS RESULTING IN 
AN AREA OF NE-E TRADES OF 20 KT TO BE CONFINED FROM 15N-20N
W OF 131W. THESE TRADES ARE FORECAST TO GRADUALLY DIMINISH IN
AREAL COVERAGE DURING THE NEXT 48 HRS AS THE TROUGH BEGINS TO
EXIT THE AREA.

THE PRES GRADIENT BETWEEN WEAK SURFACE HIGH PRES OVER SRN MEXICO 
AND THE 1008 MB LOW NEAR 16N110W HAS INCREASED THE LOW TO 
MID-LEVEL E-SE WINDS BETWEEN THE LOW AND THE SW COAST OF MEXICO
DUE TO A TIGHT PRES GRADIENT THAT HAS SET UP THERE.

THE PRESENT GULF OF PAPAGAYO EVENT OF NE 20-25 KT WINDS AS 
DEPICTED IN AN ASCAT PASS FROM NEAR 1600 UTC THIS MORNING IS 
FORECAST TO DIMINISH IN ABOUT 24 HRS AS HIGH PRES OVER THE NRN 
CARIBBEAN SEA SHIFTS E.

SRN HEMISPHERIC FRONTAL SYSTEMS CONTINUE TO SEND LONG-PERIOD 
SWLY SWELLS NWD WITH PERIODS OF 15-17 SECONDS BUILDING THE SEAS
INTO THE 8-10 FT RANGE S OF 10N BETWEEN 90W-117W. THESE 
CONDITIONS ARE FORECAST TO BE PRESENT S OF 8N BETWEEN 
90W-108W...AND S OF 6N BETWEEN 79W-87W IN ABOUT 48 HRS AND MAY 
IMPACT THE SW COAST OF MEXICO THROUGH EARLY NEXT WEEK. 

$$
AGUIRRE