[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 161803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON 16 MAY 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.

...TROPICAL WAVES...

CENTRAL ATLC TROPICAL WAVE ALONG 42W S OF 12N MOVING W NEAR 15
KT. THE WAVE IS FAIRLY WELL DEFINED IN SATELLITE IMAGERY WITH
BROAD ROTATION BUT LIMITED SHOWER/TSTM ACTIVITY.  THERE ARE NO
SIGNS OF ORGANIZATION.  THE WAVE DOES MARK THE LEADING EDGE OF A
SURGE IN AFRICAN DUST WHICH EXTENDS FROM THE ITCZ NWD TO ABOUT
20N.

E CARIBBEAN TROPICAL WAVE ALONG 66W S OF 16N MOVING W NEAR 10
KT. THE WAVE IS LOCATED WITHIN A LARGE AREA OF DISORGANIZED
CONVECTION BUT THERE IS LITTLE TO NO OBSERVED ROTATION.  THE
PRESENT POSITION IS BASED PRIMARILY ON EXTRAPOLATION.  SCATTERED
MODERATE TO STRONG CONVECTION FROM 13N-18N BETWEEN 63W-72W
INCLUDING PORTIONS OF PUERTO RICO AND SE HISPANIOLA.

W CARIBBEAN TROPICAL WAVE ALONG 82W S OF 10N MOVING W NEAR 10
KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF LOW PRESSURE
ASSOCIATED WITH A TROUGH AND LOW NEAR JAMAICA.  AS A
RESULT...THE SATELLITE SIGNATURE IS MASKED AND THE CURRENT
POSITION IS BASED MAINLY ON EXTRAPOLATION.  NO ASSOCIATED DEEP
CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N10W 9N20W 4N35W 6N43W 5N50W
8N65W.  WIDELY SCATTERED MODERATE CONVECTION FROM THE EQUATOR
NWD TO 6N BETWEEN 20W-35W.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER LEVEL TROUGH OVER CENTRAL MEXICO IS THE PRIMARY
WEATHER MAKER WITH BROAD UPPER LEVEL DIFFLUENCE TO THE EAST
PRODUCING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE W
GLFMEX.  THIS ACTIVITY SHOULD SLOWLY WANE DURING THE NEXT 24
HOURS AS THE UPPER TROUGH FLATTENS AND THE FLOW BECOMES MORE
ZONAL.  AT THE SURFACE...WEAKENING STATIONARY FRONT EXTENDS FROM
N FLORIDA NEAR JACKSONVILLE SW TO 27N90W 27N96W.  THIS FRONT IS
MOISTURE STARVED WITH LITTLE UPPER SUPPORT AND IS ONLY PRODUCING
ISOLATED SHOWERS WITHIN 75 NM EITHER SIDE OF THE BOUNDARY.
EXPECT THIS BOUNDARY TO SLOWLY DISSIPATE DURING THE NEXT 12-24
HOURS.  ELSEWHERE OVER THE SE GULF...MAIN DRY AND TRANQUIL
CONDITIONS SHOULD CONTINUE THROUGH WED.

CARIBBEAN...
1007 MB SURFACE LOW IS LOCATED JUST SE OF JAMAICA NEAR 17.5N76W
WITH A TROUGH TRAILING SWD INTO THE SW CARIBBEAN.  THE LOW IS
EMBEDDED WITHIN MODERATE UPPER LEVEL WLY FLOW WITH A WEAK UPPER
LEVEL SHORTWAVE TROUGH MOVING ACROSS HISPANIOLA.  LOW LEVEL SLY
FLOW TO THE EAST OF THE LOW IS PULLING AMPLE MOISTURE NWD ACROSS
THE CENTRAL AND E CARIBBEAN. THIS PATTERN IS GENERATING
WIDESPREAD CLOUDINESS AND SCATTERED MODERATE TO STRONG
CONVECTION FROM 13N-19N BETWEEN 62W AND 76W.  THE LOW IS
EXPECTED TO MOVE SLOWLY NEWD FOCUSING THE STRONGEST LIFT AND
DYNAMICS OVER THE NE CARIBBEAN...INCLUDING HISPANIOLA AND PUERTO
RICO...DURING THE NEXT 24 HOURS.  GIVEN THE ABUNDANCE OF
MOISTURE ACROSS THE AREA...THIS SETUP COULD POTENTIALLY PRODUCE
LOCALLY HEAVY RAINFALL AND FLOODING DURING THE NEXT DAY OR SO.
ELSEWHERE ACROSS THE AREA...MIDDLE TO UPPER LEVEL RIDGE LIES
ALONG THE N COAST OF S AMERICA.  SW FLOW AROUND THE W PERIPHERY
OF THE RIDGE IS ADVECTING UPPER LEVEL DEBRIS CLOUDINESS FROM THE
PACIFIC ACROSS CENTRAL AMERICA.

ATLANTIC...
UPPER LEVEL TROUGH LOCATED OVER THE FAR W ATLC N OF 27N W OF 66W
INTO THE W GULF CONTINUES TO PROPAGATE EASTWARD. UPPER LEVEL
RIDGE AMPLIFYING TO THE EAST OF BERMUDA. NO SIGNIFICANT WEATHER
IS BEING PRODUCED WITH THE DRY UPPER AIR/MODERATE SUBSIDENCE
WITHIN THIS AREA. THE MAIN FEATURE THAT IS DOMINATING THE REST
OF THE WESTERN/CENTRAL ATLC IS A DEEP LAYERED TROUGH N OF 27N
WITH A DISSIPATING FRONTAL BOUNDARY...REMNANT SURFACE
TROUGH...ACROSS THE AREA FROM 34N37W THROUGH 27N47W TO 25N54W.
EXTENDING S OF THE SURFACE TROF IS A BROAD AREA OF DIFFLUENCE
THAT IS DUE TO ANTICYCLONIC FLOW OVER THE CARIBBEAN AND THE W
TROPICAL ATLC. THIS IS CREATING AN ENVIRONMENT THAT IS CONDUCIVE
FOR WIDELY SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 450
NM SE OF THE TROUGH FROM 35W-50W. SCATTERED SHOWERS ARE
ELSEWHERE WITHIN 120/150 NM NW OF THE TROUGH. SURFACE RIDGING
DOMINATES THE E ATLC WITH RIDGE EXTENDING FROM THE AZORES SW TO
20N50W.  THIS PRESSURE PATTERN IS PRODUCING A TIGHT GRADIENT
OVER THE E TROPICAL ATLC AND W AFRICA RESULTING A LARGE SURGE OF
AFRICAN DUST E OF 42N FROM THE ITCZ TO 20N. IN THE UPPER
LEVELS...A CUTOFF LOW IS SITUATED JUST W OF THE CANARY ISLANDS
NEAR 29N22W WITH WEAK TROUGHING TO THE SOUTH TOWARD THE CAPE
VERDE ISLANDS.  BROAD DIFFLUENCE ALOFT SE OF THE UPPER TROUGH IS
ENHANCING ITCZ CONVECTION E OF 35W.

$$
RHOME/HALBACH




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