000
AXPZ20 KNHC 270925
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN JAN 27 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.
 
...ITCZ...
ITCZ AXIS IS CENTERED ALONG 4N78W 6N90W 6N108W 11N124W 8N140W. NO 
SIGNIFICANT CONVECTION.

...DISCUSSION...
A DEEP-LAYERED CUT-OFF LOW AND ASSOCIATED TROUGH REMAIN LOCATED OFF 
THE CALIFORNIA COAST WITH A 1001 MB SURFACE LOW ABOUT 550 NM WSW OF 
SAN DIEGO NEAR 31N128W...AND A RARE COLD FRONT ACROSS THE AREA FROM 
30N120W TO 19N125W TO 13N135W. THE UPPER TROUGH IS NEGATIVELY TILTED 
AS A VIGOROUS UPPER LEVEL JET CUTS SOUTH OF THE TROUGH...THEN SPLITS 
WITH ONE BRANCH STREAMING ENE AND THE OTHER RUNNING N INTO NORTHERN 
CALIFORNIA. A LARGE AREA OF UPPER DIFFLUENCE E OF THE TROUGH AXIS IS 
PRODUCING WIDESPREAD CLOUDINESS N OF 13N E OF 123W INTO N/CENTRAL 
MEXICO WITH EMBEDDED SHOWERS AND STRATIFORM RAIN PRIMARILY WITHIN A 
BAND BETWEEN NW MEXICO AND THE FRONT ACROSS NORTHERN PARTS OF BAJA 
CALIFORNIA AND THE GULF OF CALIFORNIA. WITH THE SURFACE LOW NEAR 31N 
THE NORTHERN PART OF THE REGION W OF 120W WILL HAVE A 25-35 KT WIND 
MAX SWING THROUGH. OPEN CELL COLD AIR STRATOCUMULUS INDICATIVE OF 
UNSTABLE AIR BEHIND THE FRONT WITH SCATTERED HEAVY SHOWERS POSSIBLE 
MAINLY N OF 28N BETWEEN 120W AND 130W.

THE UPPER LEVEL PATTERN OVER CENTRAL AMERICA IS DOMINATED BY A WEAK 
REX BLOCK WITH RIDGING FROM 10N105W NE TO THE YUCATAN PENINSULA AND 
TROUGHING FROM THE JAMAICA SW ACROSS HONDURAS/EL SALVADOR TO 5N97W. 
A LARGE MID-LEVEL HIGH CENTERED NEAR THE NORTHERN YUCATAN PENINSULA 
IS PRODUCING MODERATE/STRONG SUBSIDENCE E OF 100W AND SUPPRESSING 
MOST DEEP CONVECTION AND ABOVE NORMAL SURFACE TEMPERATURES. GAP 
WINDS CONTINUE UNABATED...AND THE RESULTANT NORTHERLY LOW-LEVEL FLOW 
HAS PUSHED THE ITCZ WELL S TO NEAR 5N. MAX WINDS WITHIN THE GULF OF 
TEHUANTEPEC ARE EXPECTED AROUND 30 KT...BUT THERE IS A POSSIBILITY 
THAT THEY COULD REACH MINIMAL GALE CRITERIA AT TIMES THROUGH TONIGHT.

$$
MUNDELL