000
AXPZ20 KNHC 100920
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU JUL 10 2008

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 
0900 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 99W N OF 05N MOVING W 10-15 KT. AN 
ILL-DEFINED 1010 MB LOW IS ALONG THE WAVE NEAR 14N99W. SCATTERED 
MODERATE CONVECTION HAS RECENTLY DEVELOPED IN THE VICINITY OF 
THE LOW FROM 12N-17N BETWEEN 98W-103W. OTHER WIDESPREAD 
CONVECTION IS LOCATED AT THE SOUTHERN EXTENT OF THE WAVE ALONG 
THE ITCZ.

TROPICAL WAVE ALONG 116W/117W S OF 19N MOVING W 15 KT. THE WAVE 
IS ILL-DEFINED AND IS MOVING THROUGH AN ENVIRONMENT OF BROAD SW 
TO WESTERLY LOW-LEVEL FLOW. THERE IS A SLIGHT ENHANCEMENT OF 
CONVECTION ALONG THE ITCZ BETWEEN 114W-120W.
 
...ITCZ...

ITCZ AXIS IS CENTERED ALONG 07N77W TO 08N89W TO 12N110W TO 
06N134W TO 06N140W. ISOLATED MODERATE CONVECTION FROM 02N-07N 
BETWEEN 78W-82W. SCATTERED MODERATE/ISOLATED STRONG FROM 04N-10N 
BETWEEN 86W-93W. NUMEROUS MODERATE/ STRONG FROM 08N-13N BETWEEN 
100W-111W. SCATTERED SHOWERS/TSTMS WITHIN 90 NM OF AXIS BETWEEN 
114W-120W AND W OF 130W.

...DISCUSSION...

SUBTROPICS...
A LARGE-SCALE BUT FLAT UPPER LEVEL RIDGE LIES ACROSS MUCH OF THE 
NORTHERN PACIFIC WATERS FROM 145W EWD INTO THE WESTERN UNITED 
STATES. THE RIDGE IS ESSENTIALLY CUT INTO TWO PARTS WITH ONE 
AXIS N OF THE AREA ALONG 37N AND THE OTHER ROUGHLY ALONG 
25N...WITH AN UPPER HIGH NEAR 25N121W. THEY ARE SEPARATED BY AN 
WESTWARD-MOVING UPPER LOW NEAR 30N133W WITH A TROUGH EXTENDING 
EWD TO ANOTHER UPPER LOW NEAR THE CALIFORNIA/MEXICO BORDER. THIS 
PATTERN HAS SUBDUED THE SUBTROPICAL RIDGE WITH ONLY A WEAK 1013 
MB HIGH NEAR 24N129W. AN OVERCAST STRATOCUMULUS FIELD LIES NW OF 
THE HIGH N OF 22N W OF 130W AND SHOWS A WEAK AREA OF LOW PRES 
NEAR 28N135W...WITH A PRESSURE OF ROUGHLY 1011 MB. ADDITIONAL 
MOSTLY OVERCAST STRATUS/STRATOCUMULUS LIES N OF 20N E OF 
130W...EXCEPT N OF 26N BETWEEN 122W-130W...AS NORTHERLY FLOW 
MOVES DOWN THE COAST OF BAJA CALIFORNIA. THE SUMMER MONSOON IS 
IN GEAR OVER NW MEXICO AND DEEP-LAYERED MOISTURE HAS FOUND ITS 
WAY UP THE GULF OF CALIFORNIA INTO THE MEXICAN STATES OF SINALOA 
AND SONORA...AND A CLUSTER OF TSTMS CONTINUES INTO THE NIGHT 
FROM THESE STATES NE INTO CHIHUAHUA.

TROPICS...
DEEP-LAYERED MOISTURE COVERS MOST OF THE TROPICAL EAST PACIFIC E 
OF 120W ALTHOUGH THERE IS SOME INTRUSION OF DRY AIR FROM THE 
WEST. THIS IS BEING CAUSED BY A COMPLETE BREAKDOWN OF THE TRADES 
THROUGH ANOMALOUSLY WESTERLY LOW-LEVEL FLOW WHICH LIES S OF A 
TROUGH AXIS ALONG 18N TO THE ITCZ...FLOWING FROM 140W WELL E 
INTO THE BROAD MONSOON-TYPE TROUGH OFF THE COAST OF MEXICO. THE 
UPPER LEVEL FLOW OVER THE TROPICS IS PREDOMINANTLY 
EASTERLY...WITH THE EXCEPTION OF A ZONE OF VARIABLE FLOW FROM 
06N-13N W OF 100W. MULTIPLE LOW-LEVEL CIRCULATIONS LIE ALONG THE 
BROAD TROUGH OFF MEXICO BUT ARE CURRENTLY FOCUSED AROUND WEAK 
LOWS S OF ACAPULCO NEAR 14N99W AND WSW OF COSTA RICA NEAR 
08N89W. MODEL GUIDANCE IS NOT VERY AGGRESSIVE WITH EITHER OF 
THESE TWO LOWS AND SHOWS VERY LITTLE DEVELOPMENT OVER THE NEXT 
FEW DAYS.

$$
BERG