[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAY 08 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N9N 2N20W 1N20W...THEN CROSSES
THE EQUATOR NEAR 34W AND CONTINUES S OF THE EQUATOR INTO NE
BRAZIL NEAR 3S43W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS N OF THE AXIS WITHIN 45 NM OF 4N29W.

...DISCUSSION...

GULF OF MEXICO...
MODERATE SUBSIDENCE WITH ASSOCIATED DRY STABLE AIR IN NW FLOW IS
OBSERVED ACROSS THE GULF AS BROAD MID/UPPER LEVEL RIDGING W OF
THE AREA SPREADS EWD MAINTAIN TRANQUIL CONDITIONS OVER THE GULF
INTO THE WEEKEND. AT THE SURFACE A RIDGE WAS ANALYZED ALONG 28N.
LATEST VISIBLE SATELLITE IMAGERY SHOWED GENERALLY MOSTLY CLEAR
SKIES ACROSS THE GULF WITH JUST A FEW SMALL CUMULUS CLOUDS OVER
PARTS OF THE WRN SECTION...AND OVER THE ERN SECTION N OF 25N
MOVING RAPIDLY N IN SLY FLOW OF 15-20 KT. A FEW THIN STRANDS OF
HIGH CIRRUS CLOUDS ARE MOVING EWD ACROSS THE FAR NRN PORTION OF
THE NE GULF...WHILE A SMOKE PLUME DUE TO INLAND FIRES OVER SE
MEXICO AND THE WRN YUCATAN PENINSULA STREAMS NW ACROSS THE SW
GULF AND BAY OF CAMPECHE S OF 26N AND W OF ABOUT 88W.
VISIBILITIES HAVE BEEN REDUCED TO 5-6 SM WITH THE PLUME ALONG
THE MEXICAN COAST. THESE CONDITIONS ARE EXPECTED TO PERSIST
THROUGH THE NEXT 36-48 HRS.

CARIBBEAN SEA...
A SHORTWAVE TROUGH EXTENDS FROM THE SE BAHAMAS SW TO ERN CUBA
AND JUST E OF JAMAICA. THE COMBINATION OF THIS TROUGH AND LOW
LEVEL MOISTURE IS RESULTING IN SCATTERED SHOWERS AND ISOLATED
TSTMS OVER THE NE PART OF THE SEA MAINLY S OF PUERTO RICO
AND THE DOMINICAN REPUBLIC. ACTIVITY IS MOST NUMEROUS OVER THE
INTERIOR OF THESE ISLANDS. OVER THE REMAINDER OF THE SEA...
A WEAK MID/UPPER LEVEL TROUGH STRETCHES NE TO SW ACROSS THE
NW PORTION...WHILE THE NRN PERIPHERY OF BROAD MID/UPPER LEVEL
RIDGING IS PRESENT OVER THE ERN PORTION TO THE E OF THE SHORTWAVE
TROUGH. THIS IS COMBINING TO ACCOUNT FOR SW MID/UPPER LEVEL
OVER THE AREA BRINGING IN SCATTERED TO BROKEN HIGH CLOUDS...
FROM CONVECTION OVER COLOMBIA...NEWD INTO ACROSS THE FAR SRN
WATERS. CONFLUENT FLOW INTO THE TROUGH IS PRODUCING MODERATE
SUBSIDENCE OVER THE NW PORTION OF THE SEA KEEPING CONDITIONS
THERE RATHER STABLE WITH ONLY SCATTERED TO BROKEN SMALL CUMULUS
CLOUDS WITH POSSIBLE ISOLATED SHOWERS NOTED MOVING WNW TO THE
S OF 20N. LOW CLOUD THIN STREAMERS ARE EVIDENT OVER THE LESSER
ANTILLES WITH POSSIBLE ISOLATED BRIEF SHOWERS. THESE CLOUDS
EMANATE WWD INTO THE CENTRAL CARIBBEAN N OF 13N.

ATLANTIC OCEAN...
THE SHORTWAVE TROUGH DESCRIBED UNDER CARIBBEAN SEA EXTENDS
NE TO BEYOND THE AREA AT 32N72W. TO ITS E...A NARROWING
MID/UPPER
RIDGE EXTENDS FROM NE OF THE AREA SW THROUGH 32N64W TO 27N66W TO
20N66W. A WEAK MID/UPPER LEVEL TROUGH IS E OF THE RIDGE FROM
32N59W TO 25N59W WITH A RIDGE TO ITS E ALONG 32N52W TO 25N52W.
THE UPPER FLOW BECOMES ZONAL E OF THE RIDGE...THEN RESPONDS TO
A BROAD DEEP LAYER TROUGH OVER THE FAR ERN ATLC STRETCHING FROM
32N28W SW TO 24N38W AND S TO 15N35W. AT THE SURFACE...A TROUGH
EXTENDS FROM CENTRAL CUBA TO THE CENTRAL BAHAMAS. WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ARE NE OF THE TROUGH WITHIN
45 NM OF 26N73W. THIS ACTIVITY IS BEING ENHANCED BY THE
SHORTWAVE TROUGH. A TINY VORT MAX SPUN OFF FROM THE TROUGH IS
RACING N NEAR 29N75W. A 1030 MB HIGH CENTER IS JUST N OF THE
AREA NEAR 32N47W WITH A RIDGE WSW TO 29N72W TO ACROSS NRN FL.
PATCHES OF BROKEN LOW AND MID LEVEL CLOUDS WITH EMBEDDED
SCATTERED SHOWERS AN ISOLATED WEAK CONVECTION ARE MOVING WWD IN
MODERATE TO STRONG ESE FLOW S OF THE RIDGE AND E OF THE SURFACE
TROUGH TO NEAR 52W. SOME SIGNS OF AFRICAN DUST/HAZE ARE NOTED
OVER THE ERN ATLC S OF 25N E OF 56W...OTHERWISE THE ENVIRONMENT
THERE REMAINS VERY SUPPRESSED WITH JUST THE TYPICAL SCATTERED TO
BROKEN STRATOCUMULUS CLOUD FIELD PRESENT N OF THE ITCZ.

$$
AGUIRRE



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