000
AXPZ20 KNHC 260927
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED MAY 26 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 
0730 UTC.

...SPECIAL FEATURE...
AN AREA OF DISTURBED WEATHER CHARACTERIZED BY A LOW TO MID LEVEL 
CYCLONIC CIRCULATION AND ASSOCIATED 1006 MB SURFACE LOW NEAR 
11N89W HAS POOLED DEEP TROPICAL MOISTURE IN THE VICINITY OF 
CENTRAL AMERICA AND SW MEXICO. THE 0244 UTC ASCAT PASS SHOWS 
20-25 KT SW INFLOW INTO THIS BROAD CIRCULATION. NUMEROUS 
MODERATE TO STRONG CONVECTION LIES WITHIN 90 NM NW SEMICIRCLE OF 
THE LOW. MEANWHILE...PERSISTENT CONVECTION LIES ALONG THE COAST 
BETWEEN THE GULFS OF PAPAGAYO AND TEHUANTEPEC WITH NUMEROUS 
MODERATE TO STRONG CONVECTION ALSO NOTED OFFSHORE WITHIN 150 NM 
OF 12N95W AND SCATTERED MODERATE TO STRONG ELSEWHERE WITHIN 75 
NM OF COAST BETWEEN 86W AND 96W. THERE IS A MODERATE PROBABILITY 
FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE OVER THE NEXT 
48 HOURS. REGARDLESS OF THE POTENTIAL FOR DEVELOPMENT...THIS 
SYSTEM IS EXPECTED TO PRODUCE VERY HEAVY RAINFALL AND FLOODING 
OVER PORTIONS OF CENTRAL AMERICA DURING THE NEXT FEW DAYS.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 11N89W TO 
08N100W TO 07N113W TO 06N121W TO 08N140W. SCATTERED MODERATE 
CONVECTION LIES WITHIN 75 NM EITHER SIDE OF THE ITCZ AXIS 
BETWEEN 109W AND 118W AND WITHIN 75 NM EITHER SIDE OF THE ITCZ 
AXIS W OF 135W. 

...DISCUSSION...
A FLAT BROAD UPPER LEVEL TROUGH COVERS THE FAR N PORTION OF 
THE DISCUSSION AREA N OF A LINE FROM 23N140W TO 24N130W INTO NRN 
MEXICO NEAR 40N110W WITH A 300-450 NM WIDE RIBBON OF DRY AIR 
CUTTING THROUGH THE BASE OF THE TROUGH AND EXTENDING SOUTHWARD 
WITH THE SOUTHERN EDGE OF THE DRY AIR SITUATED JUST TO THE N OF 
A 70-90 KT SUBTROPICAL JET STREAM WHICH ENTERS THE AREA NEAR 
18N140W AND CONTINUES E-NE TO MAZATLAN...MEXICO. 

AN ELONGATED UPPER LEVEL RIDGE EXTENDS FROM AN ANTICYCLONIC 
CIRCULATION NEAR 12N119W NORTHEASTWARD THROUGH CENTRAL MEXICO 
INTO THE BAY OF CAMPECHE. UPPER LEVEL DIFFLUENT FLOW TO THE 
SOUTH AWAY FROM THE RIDGE AXIS IS ENHANCING SCATTERED MODERATE 
CONVECTION WITHIN 75 NM OF THE ITCZ BETWEEN 109W AND 118W. 
DIFFLUENCE ALOFT CAN ALSO BE FOUND BETWEEN THE E EDGE OF THE 
RIDGE AXIS AND THE BACK EDGE OF A DIGGING UPPER TROUGH SWEEPING 
OVER THE CARIBBEAN ALONG 80W TO JUST N OF PANAMA. THE SPECIAL 
FEATURE DESCRIBED ABOVE LIES IN THIS REGION OF BROAD UPPER LEVEL 
DIFFLUENCE.

AT THE SURFACE...A RIDGE COVERS THE AREA N OF 13N W OF 110W. THE 
RIDGE IS PRODUCING A TIGHT ENOUGH PRES GRADIENT TO SUPPORT NE TO 
E 20-25 KT TRADE WINDS IN AN AREA FROM 10N TO 19N W OF 130W 
ACCORDING TO THE 0608 UTC ASCAT PASS. THE GRADIENT BETWEEN THE 
SAME RIDGE AND LOWER PRES OVER MEXICO IS PRODUCING 20-25 KT NW 
WINDS WITHIN 180 NM OF THE W COAST OF BAJA CALIFORNIA. THESE 
WINDS WILL REMAIN CONFINED TO THE AREA E OF 118W TO THE BAJA 
CALIFORNIA COAST THROUGH THE NEXT 48 HOURS WITH NO CHANGE IN 
WIND SPEED. A WEAK COLD FRONT IS EXPECTED TO REACH N WATERS WITH 
LITTLE FANFARE BY MORNING WITH THE MAIN IMPACT BEING A NEW SURGE 
OF NW SWELL WITH SIGNIFICANT WAVE HEIGHTS TO 8 FT IN NE WATERS 
WED.

ANOTHER TRAIN OF LONG PERIOD...17-19 SECOND...SWELLS WITH DEEP 
WATER WAVE HEIGHTS OF 7-9 FT HAS ARRIVED ALONG THE COAST OF 
CENTRAL AMERICA AND MEXICO AND WILL PUSH FURTHER N...IMPACTING 
THE SRN GULF OF CALIFORNIA AND NORTHERN BAJA CALIFORNIA LATER 
TODAY. S TO SW WIND WAVES ON TOP OF THE EXISTING LONG PERIOD 
SWELL IS PUSHING SIGNIFICANT WAVE HEIGHTS TO 13 FT TO THE SOUTH 
OF THE LOW PRES AND AREA OF DISTURBED WEATHER DESCRIBED AS A 
SPECIAL FEATURE ABOVE. 

$$
SCHAUER/COBB