000
AXPZ20 KNHC 171550
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAY 17 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1530 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N77W 7N100W 8N110W 10N122W 6N140W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF 
AXIS BETWEEN 78W-83W. SCATTERED MODERATE IS FROM 6N-9N BETWEEN 
92W-99W. CLUSTERS OF SCATTERED MODERATE ARE WITHIN 60 NM OF AXIS 
W OF 121W.  

...DISCUSSION...
UPPER LEVELS...
A SWLY JET WITH CORE WINDS NEAR 100 KT ORIGINATES NEAR 
15N128W AND EXTENDS NE ALONG 20N117W TO CENTRAL/SRN BAJA 
CALIFORNIA. THIS JET LIES BETWEEN BROAD UPPER TROUGHING TO THE 
N/NE AND EXTENSIVE RIDGING ACROSS THE DEEP TROPICS. UPPER 
CONFLUENCE TO THE N OF THE JET AXIS IS HELPING TO SINK AND 
STABILIZE THE ATMOSPHERE ACROSS THE NE PART OF THE DISCUSSION 
AREA. UPPER DIFFLUENCE AND MOIST S-SWLY FLOW S OF THE JET AXIS 
IS DRAWING MOISTURE FROM THE ITCZ AND ADVECTING IT TOWARD THE 
MEXICAN COAST GENERALLY BETWEEN 105W-130W. MOST OF THIS MOISTURE 
IS ONLY IN THE FORM OF A MID-HIGH LEVEL CLOUD DECK EXCEPT ALONG 
THE ITCZ WHERE LOW-LEVEL CONVERGENCE IS FUELING CLUSTERS OF 
MODERATE CONVECTION.

FARTHER E...BROAD RATHER FLAT RIDGING STRETCHES ACROSS MUCH OF 
AREA E OF 110W WITH ONE UPPER HIGH CENTERED NEAR 13N100W. A MUCH 
STRONGER SPRAWLING RIDGE IS CENTERED JUST S OF THE EQUATOR ALONG 
101W. A WEAK DIFFLUENT ZONE HAS SET UP ALONG THE ITCZ AIDING IN 
THE DEVELOPMENT OF LARGE CLUSTERS OF MODERATE TO STRONG 
CONVECTION E OF 100W. 

LOW LEVELS...
A NEARLY STATIONARY 1025 MB HIGH CENTERED NEAR 30N135W CONTROLS 
THE PATTERN ACROSS THE REGION. NE TRADES ARE NEAR 20 KT ON THE 
SRN PERIPHERY OF THE RIDGE. A SLIGHTLY STRONGER MAGNITUDE NLY 
SURGE IS OBSERVED ACROSS THE NE PORTION OF THE REGION. BOTH OF 
THESE AREAS ARE FORECAST TO CHANGE LITTLE OVER THE NEXT COUPLE 
OF DAYS.  

GAP WINDS...A 1210 UTC QSCAT PASS DEPICTED NLY WINDS IN THE 
25-35 KT RANGE ACROSS THE GULF OF TEHUANTEPEC. THIS GAP EVENT 
HAS BEEN PULSING UP AND DOWN OVER THE PAST FEW DAYS WITH WINDS 
REACHING THEIR HIGH POINT AROUND 12-15 Z. HOWEVER...THIS 
MORNING'S PASS INDICATES THAT THE PEAK WINDS HAVE BEEN ON THE 
INCREASE. IN ADDITION THE NAM MODEL...WHICH INITIALIZED THE 
CURRENT STATE VERY WELL...SUGGESTS THAT THIS PULSING SHOULD 
CONTINUE FOR THE NEXT 48 HOURS WITH SOME FURTHER INCREASE 
POSSIBLE. THEREFORE...HAVE DECIDED TO PUT UP A GALE WARNING FOR 
THIS REGION.

$$
CANGIALOSI