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AXPZ20 KNHC 230924
TWDEP

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE SEP 23 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 0845 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 84W N OF 05N IS MOVING W 15 KT. THERE IS
VERY LITTLE EVIDENCE OF THIS FEATURE AND THEREFORE ITS CURRENT
POSITION IS BASED MAINLY ON EXTRAPOLATION.

TROPICAL WAVE EXTENDS ACROSS THE GULF OF TEHUANTEPEC ALONG 94W N
OF 06N MOVING W 10-15 KT. A LARGE CLUSTER OF STRONG CONVECTION
IS OBSERVED ALONG OR JUST W OF THE WAVE AXIS N OF 13N BETWEEN
94W-97W...STEERED BY STRONG MID-UPPER NE/E FLOW. SCATTERED
CONVECTION LIES NEAR THE INTERSECTION OF THE ITCZ. WHILE
SHORTWAVE IR IMAGES REVEAL MID-LEVEL CYCLONIC TURNING NEAR
12N92W...THERE IS NO INDICATION OF A SFC LOW AS SCATTEROMETER
AND SHIP DATA SUGGEST UNIFORM SW TO W FLOW. THE WAVE IS EXPECTED
TO REMAIN IN A STRONGLY SHEARED ENVIRONMENT OVER THE NEXT DAY OR
TWO WHICH SHOULD LIMIT DEVELOPMENT.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 09N85W 08N105W 09N120W 07N140W.
SCATTERED MODERATE CONVECTION IS WITHIN 240 NM S OF THE AXIS
BETWEEN 91W AND 95W.

...DISCUSSION...

W OF 110W...
THE MID AND UPPER PATTERN CONSISTS OF AN UPPER HIGH OVER THE
TROPICS NEAR 18N130W...ANOTHER HIGH JUST N OF THE AREA NEAR
32N128W...AND AN UPPER TROUGH OVER THE BAJA PENINSULA.
WIDESPREAD DRY STABLE AIR IS ASSOCIATED WITH THIS PATTERN
ALLOWING FOR TRANQUIL WEATHER CONDITIONS. AT THE SFC...A 1025 MB
HIGH IS CENTERED NEAR 35N135W AND A QUASI-STATIONARY 1010 MB LOW
IS SITUATED WITHIN THE ITCZ NEAR 11N122W. THERE IS ENOUGH OF A
PRES GRADIENT BETWEEN THESE FEATURES TO PRODUCE 20 KT NE TRADES
OVER THE W WATERS. SIMILAR MAGNITUDE N TO NW WINDS ARE OFF THE
BAJA COAST N OF 29N BETWEEN 120W-124W...BUT EXPECTED TO DIMINISH
SHORTLY. S TO SW SWELLS (16-18 SEC PERIODS) ARE BEGINNING TO
SPREAD N OF THE EQUATOR BETWEEN 115W AND 133W. THESE SWELLS WILL
ELEVATE SEAS TO 9 FT MAINLY S OF 10N E OF 130W OVER THE NEXT
COUPLE OF DAYS.

E OF 110W...
A BROAD AREA OF LOW PRESSURE CENTERED A COUPLE HUNDRED NM SSW OF
MANZANILLO MEXICO NEAR 16N107W HAS BEEN WEAKENING CONSIDERABLY.
WHILE SATELLITE IMAGERY DOES SHOW A FAIRLY WELL DEFINED
CIRCULATION...CONVECTION IS LIMITED TO A NARROW BAND WITHIN 180
NM W OF THE ESTIMATED CENTER. AN ASCAT PASS AROUND 05Z SHOWED
ONLY A SMALL AREA OF WINDS TO 20 KT MAINLY W OF THE CENTER.
ELSEWHERE...WATER VAPOR IMAGERY DEPICTS WIDESPREAD MOISTURE OVER
THE REGION. THIS MOISTURE IS BEING DEEPENED BY THE TROPICAL WAVE
ALONG 94W...DISCUSSED ABOVE.

$$
CANGIALOSI




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