000
AXPZ20 KNHC 011544
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED DEC 01 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.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 08N83W 
TO 07N90W TO LOW PRES NEAR 11N109W TO LOW PRES NEAR 11N120W TO 
07N140W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 08N E OF 
89W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 
09N TO 13N BETWEEN 110W AND 117W. SCATTERED MODERATE CONVECTION 
IS WITHIN 120 NM N OF THE AXIS BETWEEN 127W AND 135W.

...DISCUSSION...

1025 MB HIGH PRES IS CENTERED NEAR 33N129W AND CONTINUES 
GRADUALLY DRIFTING SOUTHWARD. A RIDGE AXIS EXTENDS FROM THE HIGH 
CENTER THROUGH 24N120W TO 17N114W. THIS HIGH WILL SETTLE S OF 
30N DURING THE NEXT 48 HOURS AND WEAKEN AS A COLD FRONT 
APPROACHES THE NW WATERS. STRONG SURFACE TROUGHING EXISTS ALONG 
THE NORTHWESTERN COAST OF MEXICO N OF 20N WITH A TIGHT PRESSURE 
GRADIENT REMAINING IN PLACE BETWEEN THE TROUGHING AND HIGHER 
PRESSURE OVER THE SIERRA MADRE OCCIDENTALS PRODUCING STRONG 
NORTHERLY FLOW ACROSS THE ENTIRE GULF OF CALIFORNIA. WHILE WINDS 
HAVE APPARENTLY DROPPED BELOW GALE FORCE...0600 UTC GFS AND NAM 
MODEL GUIDANCE CONTINUES TO DEPICT ENHANCED NW WINDS IN THE 
RANGE OF 20 TO 25 KT OVER THE CENTRAL GULF. RESULTANT SEAS ARE 8 
TO 10 FT WHICH ARE SPILLING OUT S OF THE GULF TO 18N. WINDS ARE 
EXPECTED TO DIMINISH TO LESS THAN 20 KT BY 0600 UTC THU AS THE 
RIDGE WEAKENS AND THE TROUGHING BEGINS TO DISSIPATE.

THE PRESSURE PATTERN DESCRIBED ABOVE IS ALSO PRODUCING AN AREA 
OF 20 KT NE TO E TRADES FROM 10N TO 21N W OF 120W WITH RESULTANT 
SEAS OF 8 TO 10 FT WHICH ARE COMMINGLING WITH NW SWELL. THESE 
TRADES WILL DIMINISH TO LESS THAN 20 KT WITH SEAS SUBSIDING TO 
LESS THAN 8 FT BY 0000 UTC FRI. THE COLD FRONT IS FORECAST TO 
ENTER THE NW WATERS AROUND 0000 UTC THU REACHING FROM 30N129W TO 
25N133W TO 20N140W BY 1200 UTC FRI. NW WINDS OF 20 TO 25 KT WITH 
SEAS OF 8 TO 13 FT IN NW SWELL WILL ARRIVE BEHIND THE FRONT.

IN THE FAR SE PORTION OF THE AREA...SW MONSOONAL FLOW WILL 
INCREASE S OF PANAMA AND COSTA RICA AS LOW PRES LINGERS N OF 
PANAMA IN THE SW CARIBBEAN SEA. 20 KT FLOW WILL FEED INTO THE SW 
CARIBBEAN LOW AND PERSIST THROUGH AT LEAST 1200 UTC FRI. BY 
EARLY FRI...AS THE SW MONSOONAL FLOW STRENGTHENS...ADDITIONAL NE 
FLOW OUT OF THE GULF OF PAPAGAYO REGION WILL INDUCE TROUGHING 
FROM 04N TO 08N IN THE VICINITY OF 90W. 

TWO AREAS OF LOW PRES ARE EMBEDDED IN THE ITCZ. A WEAK 1012 MB 
LOW IS CENTERED NEAR 11N109W. AN EARLIER MORNING ASCAT PASS 
INDICATED 10 TO 15 KT WINDS N OF THE LOW. THE PASS ALSO SHOWED 
20 KT SOUTHERLY FLOW S OF THE LOW AND ITCZ ROUGHLY FROM 03N TO 
08N BETWEEN 101W AND 112W WHICH WAS NOT CAPTURED WELL BY MODEL 
GUIDANCE. EXPECT THE SOUTHERLY FLOW TO WEAKEN BELOW 20 KT BY 
LATE WED. ANOTHER 1012 MB LOW IS CENTERED NEAR 11N120W. MOST 
CONVECTION REMAINS IN THE AREA BETWEEN THE LOW PRESSURE CENTERS 
AND IS DESCRIBED IN THE ITCZ SECTION ABOVE.

GAP WINDS...
A STRONG COLD FRONT IS ANALYZED ALONG THE EASTERN YUCATAN 
PENINSULA INTO EASTERN GUATEMALA WITH STORM FORCE NORTHERLY 
WINDS FUNNELING SOUTH THROUGH THE CHIVELAS PASS INTO THE GULF OF 
TEHUANTEPEC. VISIBLE SATELLITE IMAGERY INDICATES THIS INITIAL 
BURST OF COOLER AND DRY AIR ALREADY EXTENDS AT LEAST TO 12N 
BETWEEN 93W AND 97W AND CONTINUES SPREADING S-SW. WINDS WILL 
DIMINISH TO GALE FORCE BY 06 UTC THU WITH MODEL GUIDANCE 
MAINTAINING MINIMAL GALE FORCE CONDITIONS THROUGH 42 HOURS.

FRESH TRADES IN THE SW CARIBBEAN SEA ARE FUNNELING INTO THE GULF 
OF PAPAGAYO. 20 TO 25 KT WINDS ARE EXPECTED IN THIS REGION AS 
LOW PRES LINGERS IN THE SW CARIBBEAN SEA THROUGH 24 HOURS. 
BEYOND 24 HOURS...SURFACE TROUGHING IS FORECAST TO DEVELOP WITH  
NEW LOW PRES DEVELOPING IN THE E PACIFIC SW OF COSTA RICA BY 48 
HOURS.

$$
HUFFMAN