Subject: Pacific-EN: Tropical Weather Discussion

From: SIU Weather Processor <[email-masked]>
Date: Fri, 21 Jan 2005 03:20:03 -0600

AXPZ20 KNHC 210919
TWDEP

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JAN 21 2005

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
0845 UTC.

..ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS ALONG 3N78W 1N93W 4N103W
8N114W 4N126W 6N136W 5N140W. SCATTERED MODERATE CONVECTION
WITHIN 30 NM OF A LINE FROM 2N94W TO 3N97W. ISOLATED MODERATE
NEAR 7N109W 7N120W AND 8N133W.

..DISCUSSION...
W OF 110W...
A LARGE UPPER RIDGE IS NOSING IN OVER THE NW PORTION OF THE
REGION TONIGHT. A STRONG ZONAL JET STILL LIES W OF THE REGION
ALONG 30N..HAVING DIPPED SOUTHWARD ABOUT 5 DEGREES THE PAST 24
HRS. A LARGE AREA OF MOISTURE COVERS THE RIDGE AREA BUT IS
MOSTLY IN THE FORM OF HIGH CLOUDINESS.

FURTHER E A CUTOFF UPPER LOW WAS LOCATED NEAR 27.5N114.7W ON THE
MID COAST OF THE BAJA PENINSULA. THE LOW WAS STATIONARY. A 75 KT
JET SEGMENT WAS DIGGING S ALONG 123W WHILE A JET OF EQUAL VALUE
WAS LIFTING N OVER NW MEXICO ALONG 111W. A NARROW SWATH OF
MULTILAYERED CLOUDS WAS ADVECTING INLAND WITH THE JET OVER NW
MEXICO AND SW ARIZONA. AN AREA OF SUBSIDENCE WAS LOCATED S OF
THE LOW CENTER BETWEEN 110W AND 120W WHERE THE UPPER FLOW WAS
CONVERGENT.

FURTHER S BETWEEN 5N AND 15N AN UPPER TROUGH WAS LOCATED FROM
15N140W SW TO 5N150W. THE TROUGH WAS HELPING PRODUCE CONVECTION
ALONG THE ITCZ WITH DIVERGENT FLOW E OF THE TROUGH. AN OPEN
RIDGE BULGES N BETWEEN 115W AND 135W TO AROUND 10N.

E OF 110W...
AN UPPER RIDGE WAS CENTERED NEAR 7N100W AND RIDGES NORTHWARD
ALONG 100W OVER MEXICO BACK TO THE DESERT SW. THE RIDGE HAS
CONSIDERABLE HIGH CLOUDINESS THROUGHOUT FROM MOISTURE ADVECTING
INTO IT FROM THE EQUATORIAL REGION. THE RIDGE FLATTENS OUT TO
THE E BUT EXTENDS ALL THE WAY TO THE EQUADORIAN COAST NEAR
EQUATOR AND 80W. THE RIDGE APPEARS TO BE AIDING CONVECTION ALONG
THE ITCZ NEAR 3N95W WHERE UPPER WINDS ARE LIGHT AND VARIABLE.

AN UPPER TROUGH OVER THE CARIBBEAN AND NORTHWARD CURVES
CYCLONICALLY OVER CENTRAL AMERICA WHERE SPEED CONVERGENCE IS
PRODUCING CONSIDERABLE SUBSIDENCE N OF 8N AND E OF 90W.

SURFACE WINDS IN GULF OF TEHUANTEPEC HAVE DECREASE TONIGHT TO
BETWEEN 20 AND 25 KT DUE TO A WEAKENING OF THE PRESSURE GRADIENT
OVER THE ISTHMUS.

$$
RRG

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