000
AXPZ20 KNHC 260951
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU JAN 26 2012

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 07N77W TO 08N84W TO 05N88W WHERE 
LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES 
W TO 08N109W TO BEYOND 04N140W. SCATTERED MODERATE CONVECTION IS 
NOTED FROM 04N TO 13N BETWEEN 100W AND 108W. SCATTERED MODERATE 
TO STRONG CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF A 
LINE FROM 07N122W TO 06N131W.

...DISCUSSION...

A DEEP LAYERED CYCLONE OVER CENTRAL TEXAS HAS AN UPPER TROUGH 
EXTENDING S ACROSS CENTRAL OLD MEXICO TO THE PACIFIC AT 19N105W 
TO 11N113W. THE NARROW PLUME OF UPPER MOISTURE ORIGINATING IN 
THE TROPICAL PACIFIC THAT HAS BEEN STREAMING NE INTO THE 
CONVECTION AHEAD OF THIS CYCLONE HAS ALMOST COMPLETELY 
EVAPORATED ANS IT MOVES NE ACROSS CENTRAL OLD MEXICO AND THE W 
GULF OF MEXICO. IN THE MEANTIME AN UPPER CYCLONE HAS CUT OFF 
FROM THE TROUGH AT 19N137W WITH A TROUGH EXTENDING THROUGH 
ANOTHER UPPER CYCLONE AT 12N138W...TO TROUGH BASE AT 06N137W. AN 
UPPER ANTICYCLONE IS CENTERED NEAR 19N126W WITH ITS ENVELOPE OF 
ANTICYCLONIC FLOW COVERING THE UPPER LEVELS N OF 22N W OF 110W. 
UPPER MOISTURE ORIGINATING OVER THE PACIFIC N OF THE HAWAIIAN 
ISLANDS IS SPREADING E ALONG THE N PERIPHERY OF THIS 
ANTICYCLONE...ROUGHLY ALONG 35N...AND SPILLING SE ACROSS SE 
CALIFORNIA AND MOST OF NEW MEXICO AND ARIZONA...AND WILL MOVE 
ACROSS EXTREME NORTHERN OLD MEXICO LATER TODAY. OTHERWISE THE 
UPPER LEVELS APPEAR VERY DRY N OF 17N W OF 95W...AND FROM O6N TO 
17N W OF 137W.

AN UPPER ANTICYLONE IS CENTERED JUST S OF THE AREA NEAR 03S127W 
WITH A RIDGE EXTENDING N ACROSS THE EQUATOR TO A GENTLE CREST 
ALONG POINTS 10N137W TO 17N126W TO 08N110W TO BEYOND 00N104W. AN 
AREA OF UPPER DIFFLUENCE IS INDUCED JUST TO THE E OF THE UPPER 
TROUGH OVER THE DEEPS TROPICS NEAR 06N137W WITH THE DIFFLUENCE 
SPREADING E UNDER THE WESTERN PORTION OF THIS TROPICAL RIDGE. 
THIS IS ENHANCING THE DEEP CONVECTION. UPPER LEVEL GUIDANCE 
SUGGESTS THIS AREA OF UPPER DIFFLUENCE AND THUS ENHANCED 
CONVECTION MAY CONTINUE...BUT SHIFT SLIGHTLY TO THE NE TONIGHT 
AND FRI.     

AN UPPER RIDGE EXTENDS FROM SE TO NW ACROSS THE W CARIBBEAN TO A 
CREST OVER THE NE GULF OF MEXICO AT 28N85W. THIS RESULTS IN 
SOUTHWESTERLY UPPER FLOW OVER THE TROPICAL PACIFIC TO THE E OF 
100W...WITH AN AREA OF UPPER DIFFLUENCE NEAR 06N103W ENHANCING 
THE AREA OF SCATTERED MODERATE CONVECTION PREVIOUSLY DESCRIBED. 
THE RESULTANT DEBRIS MOISTURE IS ADVECTED NE...BUT SEEMS TO 
EVAPORATE BEFORE REACHING CENTRAL AMERICA.
 
AT THE LOW LEVELS A SURFACE HIGH IS QUASI-STATIONARY NEAR 
34N130W WITH A BROAD RIDGE ACROSS THE AREA N OF THE ITCZ AND W 
OF 105W. NE TRADES AT 20 KT ARE OBSERVED S OF THE ASSOCIATED 
RIDGE TO ALONG 06N TO THE W OF 123W...WITH SEAS 8 TO 12 FT IN 
LONG PERIOD NW SWELL MIXING WITH THE NE TRADE SWELL. MIXED N 
SWELL IS MAINTAINING COMBINED SEAS OF 7 TO 10 FT ELSEWHERE W OF 
LINE FROM THE SW BAJA CALIFORNIA PENINSULA TO 08N120W TO 
03N140W. BY TONIGHT...THE GRADIENT WILL SHIFT THE AREA OF 
ENHANCED NE TO E WINDS AT 20 TO 25 KT TO ACROSS THE PACIFIC 
WATERS FROM 23W TO 32N TO THE W OF 124W...WITH COMBINED SEAS OF 
10 TO 14 FT IN MIXED NE AND NW SWELL. FURTHER S...ROUGHLY FROM 
07N TO 15N TO THE W OF 130W...NE WINDS WILL CONTINUE AT 20 KT 
WITH SEAS 9 TO 11 FT IN THE MIXED NE AND NW SWELL. LONG PERIOD 
NE AND NW SWELL WILL MAINTAIN COMBINED SEAS OF 7 TO 10 FT ACROSS 
THE REMAINDER OF THE DISCUSSION AREA TO THE N OF 10N W OF 115W 
AND FROM 04N TO 10N W OF 120W.

GULF OF CALIFORNIA...NW TO N WINDS HAVE DIMINISHED TO 15 TO 20 
KT OVER THE GULF OF WATERS TO THE N OF 24N...AND SHOULD FURTHER 
DIMINISH TO 10 TO 15 KT LATER TODAY. NORTHERLY WINDS WILL 
INCREASE AGAIN TO 15 TO 20 KT OVER THE NORTHERN GULF OF 
CALIFORNIA WATERS ON SAT MORNING.
 
GULF OF PAPAGAYO...NE WINDS WILL CONTINUE TO PULSE AT 15 TO 20 
KT FOR THE NEXT 48 HOURS THEN INCREASE TO 20 KT BY MIDDAY SAT.

GULF OF TEHUANTEPEC...A COLD FRONT WILL MOVE THROUGH THE SW GULF 
OF MEXICO TODAY FOLLOWED BY STRONG NORTHERLY WINDS. THESE WINDS 
WILL SURGE THROUGH THE ISTHMUS OF TEHUANTEPEC AT 20 KT AROUND 
SUNSET TODAY AND SHOULD STRENGTHEN TO MINIMAL GALE FORCE LATE 
TONIGHT...WITH THE GALE CONDITIONS LASTING THROUGH FRI 
AFTERNOON. NOTE THAT MODEL GUIDANCE HAS BACKED OFF CONSIDERABLY 
ON THE STRENGTH AND THE DURATION OF THIS EVENT...AND THUS OUR 
TEXT AND GRAPHICAL PRODUCTS HAVE BEEN ADJUSTED. THIS LATEST 
GUIDANCE STILL SUGGESTS THE NORTHERLY WINDS WILL DIMINISH TO 20 
TO 25 KT BY EARLY SAT...BUT INCREASE AGAIN TO A GALE LATE SAT 
NIGHT...AND CONTINUING THROUGH SUNRISE MON.

$$
NELSON