000
AXPZ20 KNHC 251553
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JAN 25 2007

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1530 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 3N77W 6N85W 4N95W 7N113W 4N140W. 
SCATTERED MODERATE CONVECTION WITHIN 120 NM OF AXIS E OF 90W. 
WIDELY SCATTERED SHOWERS WITHIN 90 NM OF THE AXIS W OF 130W.

...DISCUSSION...

THE OMEGA BLOCK FROM YESTERDAY HAS TRANSITIONED TO A REX BLOCK 
AS THE CLOSED UPPER LOW OVER NW MEXICO HAS SLIPPED BENEATH AN 
UPPER RIDGE BUILDING OVER THE INTERMOUNTAIN WEST. ANOTHER CLOSED 
DEEP-LAYERED LOW OFF THE N CALIFORNIA COAST IS MOVING NE BUT 
WITH A TRAILING SHORTWAVE MOVING ACROSS THE AREA FROM 30N127W TO 
18N140W. A WEAKENING COLD FRONT IS ASSOCIATED WITH THIS 
TROUGH...FROM 30N130W AND STALLING NEAR 26N140W...AND ANY 
ASSOCIATED SHOWER ACTIVITY IS MEAGER AT BEST. NEARLY ZONAL FLOW 
AND SUBSIDENT AIR S OF 24N...ALONG WITH THE SUBTROPICAL 
HIGH...ARE PRODUCING RATHER TRANQUIL CONDITIONS ACROSS MUCH OF 
THE AREA W OF 110W. THE SUBTROPICAL JET STILL EXTENDS FROM 
10N140W NE INTO CENTRAL MEXICO...BUT THE OVERALL HIGH CLOUDINESS 
HAS THINNED OUT COMPARED TO THE LAST FEW DAYS AS THE PATTERN 
DE-AMPLIFIES A BIT. 

AS A SIDE NOTE...THE CLOSED UPPER LOW AND COLD LOW-LEVEL AIR 
BLOCKED OVER THE MEXICAN PLATEAU HAS ALLOWED FOR SOME SNOW TO 
FALL OVER NRN MEXICO OVER THE PAST DAY OR SO. IN FACT...IT HAS 
SNOWED IN CHIHUAHUA MEXICO SINCE LAST EVENING AND THE 1200 UTC 
OBSERVATIONS INDICATES 3 CM (1.18 IN) OF SNOW ON THE GROUND.

FARTHER E...A FLAT E/W ORIENTED RIDGE AXIS EXTENDS ACROSS THE 
CARIBBEAN TO ABOUT 10N100W WITH MOST OF THE AREA DOMINATED BY 
MODERATE SUBSIDENCE. THERE IS SOME DIFFLUENCE OVER THE ITCZ 
WHICH HAS INITIATED SCATTERED TSTMS E OF 94W. A GALE EVENT HAS 
BEGUN OVER THE GULF OF TEHUANTEPEC...BUT WINDS ARE ONLY EXPECTED 
TO REACH 40 KT OR SO AND THE ENTIRE EVENT SHOULD BE OVER BY FRI 
AFTERNOON. WINDS OVER THE GULF OF PAPAGAYO ARE REMAINING 
PERSISTENTLY NEAR 20 KT WITH A FEW EPISODES OF WINDS REACHING 25 
KT.

$$
BERG