000
AXPZ20 KNHC 191532
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN DEC 19 2010

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 
1500 UTC.

TROPICAL LOWS...

WELL DEFINED LOW PRES 1010 MB NEAR 09N114W HAS ACTIVE PERSISTENT 
CONVECTION NEAR THE CENTER. SW WINDS 15-20 KT ARE NOTED WITHIN 
ABOUT 120 NM SE QUADRANT WITH SEAS TO 7-8 FT. THE LOW IS 
EXPECTED TO MOVE W AT 10-15 KT WITH LITTLE CHANGE THROUGH 48 
HOURS THEN WEAKEN W OF 120W. WEAK LOW PRES 1010 MB IS MEANDERING 
NEAR 07N86W WITH LITTLE CONVECTION. SW WINDS 15-20 KT ARE NOTED 
WITHIN ABOUT 180 NM SE QUADRANT WITH SEAS TO 7-8 FT. THE LOW IS 
EXPECTED TO MOVE SLOWLY THROUGH 48 HOURS WITH LITTLE CHANGE.

ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N78W TO A 
LOW PRES NEAR 07N86W TO SECOND LOW PRES NEAR 09N114W TO 07N1140W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM OF THE
LOW NEAR 09N114W.

DISCUSSION...

SMALL AREA OF DEEP CONVECTION N OF THE ITCZ NEAR 16N138W IS DUE 
TO TRADE WIND CONVERGENCE NEAR THE SURFACE AND DIFFLUENT FLOW 
ALOFT. WATER VAPOR IMAGERY SHOWS DEBRIS MOISTURE IN THE TROPICS 
FROM 07N TO 17N W OF 133W. LONG WAVE N OF THE AREA ALONG 135W 
AND ZONAL FLOW BETWEEN 25N AND 35N W OF THE TROUGH AXIS IS ACTING
TO BRING DEEP MOISTURE INTO THE WEST COAST OF THE U.S. AND ALLOW 
SEVERAL LOW PRESSURE SYSTEMS TO MOVE QUICKLY EASTWARD ALONG THE 
NORTHERN PART OF THE DISCUSSION AREA DRAGGING COLD FRONTS INTO 
THE SUBTROPICS. BUT WITHOUT MUCH UPPER LEVEL SUPPORT STRONG WINDS
ASSOCIATED WITH THE FRONT WILL REMAIN GENERALLY N OF 30N WITH THE
PRIMARY EFFECT S OF 30N BEING PERIODS OF LARGE NW SWELL SWEEPING 
INTO THE NORTHERN PART OF THE TROPICAL EAST PACIFIC. A COLD FRONT
THAT EXTENDS FROM 32N127W TO 27N140W HAS A 20-25 KT WIND SHIFT 
ALONG THE FRONT AND SEAS TO 12 FT IN NW SWELL. MULTIPLE SECONDARY
SURGES WILL PUSH THE NORTHERN SEGMENT OF THE FRONT E TO THE 
NORTHERN BAJA CALIFORNIA PENINSULA BY MON NIGHT. SEAS W OF THE 
FRONT WILL BUILD TO 13-14 FT IN LONG PERIOD NW SWELL BUT SUBSIDE 
TO ABOUT 11 FT BEFORE REACHING THE NORTHERN BAJA PENINSULA.    
  
GAP WINDS...
A COLD FRONT OVER THE SE GULF OF MEXICO IS SUPPORTING 20 KT N 
WINDS IN THE GULF OF TEHUANTEPEC. MODEL GUIDANCE INDICATES THAT 
SOUTHERLY RETURN FLOW WILL BECOME ESTABLISHED OVER THE GULF OF 
MEXICO LATER TODAY. EXPECT TO SEE SOME LATE NIGHT DRAINAGE FLOW 
RESULTING IN NORTHERLY 15-20 KT WINDS AROUND SUNRISE MON THROUGH 
WED THIS WEEK...AND PERHAPS 20-25 KT ON THU AND FRI. DEPENDING 
ON THE STRENGTH OF THE LOW PRESSURE AREA NEAR 07N86W... EXPECT 
DIURNAL NE WINDS TO SURGE AT 15-20 KT IN THE GULF OF PAPAGAYO 
LATE TONIGHT...BUT NOT PERSIST LONG ENOUGH TO BUILD 8 FT SEAS.

$$
MUNDELL