[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN 20 FEB 2005

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N0 1N20W 2S40W 3S50W. WIDELY
SCATTERED MODERATE CONVECTION IS BEING TRIGGERED ALONG AN
OUTFLOW BOUNDARY MOVING SW ACROSS SW GHANA AND THE IVORY COAST.
SCATTERED MODERATE WITHIN 175 NM OF THE AXIS BETWEEN 10W-21W.
ISOLATED SHOWERS/TSTMS S OF 4N BETWEEN 25W-38W. SCATTERED
MODERATE OVER THE AMAZON DELTA S OF 2N BETWEEN 49W-52W.

...DISCUSSION...

GULF OF MEXICO...
STRONG HIGH PRES HAS SHIFTED E OF THE AREA OVER THE W ATLC
WATERS WITH BROAD SE/S RETURN FLOW APPROACHING THE N GULF COAST.
A SPLIT UPPER LEVEL PATTERN IS CENTERED OVER THE AREA WITH PART
OF THE FLOW RIDING NEWD INTO A RIDGE LOCATED OVER THE OH
VALLEY...AND THE OTHER PART DROPPING S TO A TROF OFF THE E COAST
OF THE YUCATAN PENINSULA. A 90-100 KT JET OVER MEXICO IS
ADVECTING A FEW HIGH CLOUDS TOWARDS THE SE U.S. AND ONLY A FEW
LOWER CLOUDS COVER THE REST OF THE GULF WATERS. A FEW SHOWERS
ARE LOCATED UP TO 150 NM OFF THE TX COAST MOVING EWD BUT SHOULD
NOT POSE A MAJOR PROBLEM GIVEN THE LACK OF DYNAMICS. THE PATTERN
WILL CHANGE LITTLE THRU WED AS AN E/W ORIENTED RIDGE SETS UP
FROM S FL TO S TX BUT A COLD FRONT WILL MOVE OFF THE TX/LA COAST
WED NIGHT AND STALL OVER THE N GULF WATERS. SCATTERED
SHOWERS/TSTMS WILL PRECEDE THE FRONT...FORMING ALONG THE N GULF
COAST AS EARLY AS TUE EVENING.

CARIBBEAN...
STRONG HIGH PRES OVER THE W ATLC WATERS IS BUILDING TO THE S AND
INCREASING THE TRADES OVER THE CARIBBEAN WITH GALE CONDITIONS
BEING OBSERVED OFF THE COAST OF COLOMBIA. WAVES OF LIGHT SHOWERS
CONTINUE TO PLUNGE SWD FROM THE ATLC WATERS TO THE E
CARIBBEAN...AND THEN TURN TO THE W TOWARDS CNTRL AMERICA. A
FAIRLY SIZEABLE AREA OF SHOWERS IS CURRENTLY MOVING SWD ACROSS
THE WINDWARD ISLANDS TO THE ABC AND ADJACENT VENEZUELAN ISLANDS.
ANOTHER BAND OF SHOWERS...ONLY ABOUT 50 NM WIDE...IS JUST ABOUT
TO MOVE ACROSS THE DOMINICAN REPUBLIC...PUERTO RICO...THE VIRGIN
ISLANDS...AND FAR NRN LEEWARD ISLANDS. THESE SHOWERS ARE
ASSOCIATED WITH A WEAKENING FRONTAL BOUNDARY AND SO THEY SHOULD
BE ABLE TO PERSIST OVER THE CARIBBEAN WATERS FOR MUCH OF THE
UPCOMING WEEK. A BROAD UPPER TROF OVER CNTRL AMERICA IS
PRODUCING MODERATE/STRONG SUBSIDENCE OVER THE ENTIRE AREA AND
THUS IS LIMITING THE DEVELOPMENT OF DEEP CONVECTION. THE PATTERN
IS EXPECTED TO BECOME PROGRESSIVELY ZONAL THRU THE WEEK AS THE
LOW/TROF LIFTS NE AND DISSIPATES.

ATLANTIC...
A LARGE AREA OF BROKEN STRATOCUMULUS HAS BEEN ADVECTED OVER THE
W ATLC WATERS DUE TO STRONG COLD ADVECTION...WITH THE
RESPONSIBLE COLD FRONT PUSHING WELL TO THE E ALONG 32N43W 24N50W
TO THE NRN LEEWARD ISLANDS. THE UPPER FLOW OVER THE W ATLC IS
FLATTENING OUT WITH A STRONG 130 KT JET CORE LYING ALONG 30N
JUST SE OF BERMUDA. A SHORTWAVE TROF IS EMBEDDED WITHIN THE MAIN
TROF EXTENDING NW OF 30N40W WITH DOWNSTREAM DIFFLUENCE PRODUCING
SCATTERED MODERATE CONVECTION N OF 27N BETWEEN 36W-41W...OR JUST
E OF A PRE-FRONTAL TROF ALONG 24N43W 31N42W. FARTHER S...WEAK
SFC FLOW EXTENDS E OF THE LESSER ANTILLES WITH A TENACIOUS TROF
EXTENDING ALONG 16N46W 21N48W AND PRODUCING ISOLATED SHOWERS IN
ITS VICINITY. A BROAD UPPER TROF COVERS THE E ATLC WATERS ALONG
23W WITH A CLOSED UPPER LOW CENTERED N OF THE AREA NEAR 33N27W.
ISOLATED SHOWERS ARE CURRENTLY LOCATED SW OF THE CANARY ISLANDS
FROM 22N-32N BETWEEN 17W-32W...BUT THE PRECIP WILL BECOME MORE
SCATTERED THRU THE WEEK AS THE CONVECTION ASSOCIATED WITH THE
CNTRL ATLC FRONT MOVES EWD REACHING THE CANARY ISLANDS BY WED.

$$
BERG


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