Subject: Pacific-EN: Tropical Weather Discussion

From: SIU Weather Processor <[email-masked]>
Date: Tue, 11 Jan 2005 21:45:15 -0600

AXPZ20 KNHC 120344
TWDEP

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JAN 12 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.

..ITCZ...
AXIS ALONG 5N77W 4N92W 5N110W 6N130W 9N140W. SCATTERED MODERATE
CONVECTION IS WITHIN 60 NM OF AXIS BETWEEN 130W-134W...ALSO W OF
138W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM N OF AXIS
BETWEEN 83W-87W.

..DISCUSSION...
N OF 20N...
BROAD MID/UPPER LEVEL RIDGE WITH AXIS FROM 32N131W TO BEYOND
20N130W SITS BETWEEN A LARGE DEEP LAYERED LOW W OF AREA NEAR
150W...AND ANOTHER POWERFUL LOW PRESSURE SYSTEM INLAND OVER
NEVADA. DESPITE THE RIDGING OVER AREA...SW FLOW IS VERY STRONG
WITH A JET STREAM OF 110-130 KT OVER FAR NW CORNER OF AREA.
DOWNSTREAM OF THE RIDGE AXIS AND S OF THE SW UNITED STATES
LOW...A STRONGER NW JET STREAM OF 130-150 KT EXTENDS FROM
32N130W TO OVER SOUTHERN CALIFORNIA...NORTHERN BAJA CALIFORNIA
PENINSULA...NW MEXICO. OVER MAINLAND MEXICO...STRONG SW-W FLOW
IS MAINLY N OF 27N...WITH MUCH LIGHTER WINDS S OF 27N. A SURFACE
COLD FRONT EXTENDS FROM SW ARIZONA ACROSS THE NORTHERN PORTIONS
OF THE SEA OF CORTEZ AND BAJA CALIFORNIA TO 25N125W. SCATTERED
SHOWERS ARE ALONG THE FRONT...WITH ONLY A FEW SHOWERS W OF THE
FRONT OVER CALIFORNIA. MOST OF THE SIGNIFICANT CLOUDINESS IS W
OF 135W WHERE DEEP TROPICAL MOISTURE IS BEING PULLED NORTHWARD
BY STRONG LOW NEAR 150W. THIS AREA WILL BE THE FOCUS FOR
INCREASING CONVECTION AND SCATTERED THUNDERSTORMS OVER THE NEXT
24 HOURS AS THE LOW MOVES SLOWLY EASTWARD. THE RIDGE OVER THE
AREA WILL AMPLIFY ALONG 128W DURING THE NEXT 24 HOURS AS THE SW
UNITED STATES LOW DIGS SOUTHWARD OVER THE SOUTHERN ROCKIES AND
NORTHERN MEXICO. AS A RESULT...STRONG UPPER LEVEL NW WINDS WILL
PUSH SOUTHWARD BEHIND THE LOW OVER NORTHERN HALF OF MEXICO.

S OF 20N W OF 100W...
RELATIVELY TRANQUIL CONDITIONS PREVAIL AS TWO HIGHS CONTROL THE
FLOW IN THIS AREA. THE RIDGE MENTIONED IN SECTION N OF 20N IS
ANCHORED BY A HIGH CENTERED NEAR 12N132W...WITH ANOTHER SMALLER
HIGH LOCATED NEAR 9N110W. AS A RESULT...ANTICYCLONIC UPPER LEVEL
FLOW AND ASSOCIATED MODERATE TO LOCALLY STRONG SUBSIDENCE IS
OBSERVED OVER MOST OF AREA. THE EXCEPTION TO THIS IS A WEAK
NE-SW MID/UPPER TROUGH WHICH SPLITS THE HIGHS...EXTENDING
WESTERN MEXICO NEAR 20N103W TO 5N123W. NARROW BAND OF MOISTURE
LIES ALONG THE TROUGH. SCATTERED MODERATE ITCZ CONVECTION
BETWEEN 130W-134W IS BEING ENHANCED BY WEAK WESTWARD-MOVING LOW
LEVEL CIRCULATION MOVING ALONG ITCZ NEAR 132W. THE MID/UPPER
TROUGH WILL MOVE SE ACROSS SOUTHERN MEXICO OVER THE NEXT 24
HOURS...LEAVING AREA UNDER PREDOMINANT HIGH ALOFT.

S OF 20N E OF 100W...
NEARLY STATIONARY MID/UPPER TROUGH CONTINUES OVER CENTRAL
AMERICA FROM HONDURAS AND EL SALVADOR SW TO NEAR 5N100W. SHARP
MOISTURE GRADIENT EXISTS ON EITHER SIDE OF THE TROUGH...WITH
SCATTERED MODERATE CONVECTION E OF THE TROUGH FROM THE ITCZ
NORTH TO THE COSTA RICA/PANAMA BORDER...AND MAINLY DRY
CONDITIONS W OF TROUGH. THIS GENERAL PATTERN IS EXPECTED TO
PERSIST...WITH ONLY CHANGE BEING A MID/UPPER TROUGH MOVING
ACROSS SE MEXICO DURING THE NEXT 24 HOURS. ONLY A SLIGHT
INCREASE IN MOISTURE IS EXPECTED OVER SE MEXICO WITH THE PASSAGE
OF THE TROUGH.

LIGHT SURFACE WINDS ARE EXPECTED OVER THE GULF OF TEHUANTEPEC
REGION OVER THE NEXT 24-48 HOURS...WHILE WINDS OVER THE GULF OF
PAPAGAYO WILL BE AROUND 20 KT FOR ANOTHER 12 HOURS OR SO.

$$
MOLLEDA

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