[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171100
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

CENTRAL ATLC TROPICAL WAVE ALONG 49W S OF 11N MOVING W 15 KT.
THE WAVE IS EMBEDDED IN THE EASTERLY TRADE WIND FLOW. ISOLATED
SHOWERS ARE WITHIN 60 NM OF THE ITCZ AXIS. THE WAVE IS PRECEDING
A SURGE OF AFRICAN DUST.

E CARIBBEAN TROPICAL WAVE ALONG 70W S OF 16N MOVING W 10 KT.
THE LOW-LEVEL FLOW AROUND THE WAVE IS BEING AFFECTED BY THE
BROAD AREA OF LOW PRESSURE OVER THE W CARIBBEAN AND WITH DENSE
CLOUD COVER ITS SIGNATURE IS VERY DIFFICULT TO LOCATE. THE WAVE
IS MOVED BASED ON CONTINUITY. SCATTERED MODERATE CONVECTION IS
MOVING E AWAY FROM THE WAVE...CAUGHT IN THE MID/UPPER FLOW AND
IS FROM 14N-20N BETWEEN 63W-67W INCLUDING PUERTO RICO AND THE
VIRGIN ISLANDS. THIS WILL BRING FLASH FLOODS AND POSSIBLE
MUDSLIDES TO THE ISLANDS HIGHER ELEVATIONS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N13W 10N20W 5N33W 7N48W 6N59W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM OF THE AXIS
FROM 27W-37W AND WITHIN 90 NM OF THE COAST TO INLAND OVER
LIBERIA FROM 7W-10W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 90 NM OF THE AXIS E OF 17W TO INLAND OVER E
GUINEA...INLAND AND WITHIN 100 NM OF LIBERIA/SIERRA LEONE S OF
8N W OF 10W...AND WITHIN 75 NM OF 5N FROM 15W-21W. CLUSTERS OF
SIMILAR CONVECTION ARE WITHIN 120 NM ALONG THE SW COAST OF
AFRICA E OF 7W TO JUST ACROSS THE PRIME MERIDIAN...WITHIN 150 NM
S OF THE AXIS FROM 37W-43W...AND WITHIN 120/150 NM ALONG THE
COAST OF SOUTH AMERICA FROM 50W-58W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL LOW IS IN THE W GULF NEAR 27N96W EMBEDDED WITHIN
A LARGER MID/UPPER LEVEL TROUGH COVERING THE W GULF W OF 90W.
SCATTERED SHOWERS REMAIN IN THE BAY OF CAMPECHE S OF 22N W OF
93W. ELSEWHERE...WEAK 1010 MB LOW REMAINS CENTERED S OF
LOUISIANA NEAR 27N91W WITH A SURFACE TROUGH EXTENDING FROM THE
ALABAMA COAST SW TO 25N95W. THIS BOUNDARY HAS THE POTENTIAL OF
SUPPORTING ISOLATED SHOWERS OVER THE N GULF.

E GULF OF MEXICO...CARIBBEAN...AND W ATLANTIC...
AT THE SURFACE...A SURFACE TROUGH EXTENDS FROM THE TURKS AND
CAICOS SW TO A 1007 MB LOW CENTERED OVER HAITI NEAR 18N74W THEN
TRAILING S TO A SECOND 1007 MB LOW IN THE SW CARIBBEAN NEAR
13N79W TO 12N83W. THE N LOW IS NOW DRIFTING E OVER HISPANIOLA
WHILE THE S LOW CONTINUES TO DRIFT SLOWLY WEST. ALTHOUGH NEITHER
LOW HAS BECOME BETTER ORGANIZED THE N LOW IS NOW GENERATING
SCATTERED MODERATE/STRONG CONVECTION COVERS ALL OF HAITI AND THE
IMMEDIATE SURROUNDING AREA. A WEAKENING SURFACE RIDGE IN THE W
ATLC EXTENDS FROM A 1022 MB HIGH E OF BERMUDA NEAR 33N59W W TO
31N74W. THE UPPER FLOW IS DOMINATED BY AN UPPER HIGH LOCATED
NEAR 13N67W WITH ANTICYCLONIC FLOW COVERING THE AREA S OF 27N
FROM 43W-95W BECOMING NARROWER N OF 26N FROM 63W-90W. THIS IS
ADVECTING DEEP-LAYERED MOISTURE FROM THE E PACIFIC OVER CENTRAL
AMERICA TO OVER THE W CARIBBEAN AND PRODUCING A BROAD AREA OF
UPPER DIFFLUENCE OVER THE ENTIRE AREA. THESE DYNAMICS ARE
INTERACTING WITH THE TROPICAL WAVE AND PLENTIFUL MOISTURE SUPPLY
TO PRODUCE A LARGE CONVECTIVE CLUSTER OVER PUERTO RICO/VIRGIN
ISLANDS ASSOCIATED WITH THE TROPICAL WAVE. IN ADDITION...STRONG
CONVECTION IS DEVELOPING OVER COLOMBIA AND E PANAMA MOVING INTO
THE S CARIBBEAN S OF 12N BETWEEN 71W-78W.

REMAINDER OF THE ATLANTIC...
A REMNANT FRONTAL TROUGH REMAINS ALONG 31N45W 24N54W 21N67W.
BROAD UPPER DIFFLUENCE E OF THE TROUGH COVERS THE AREA FROM
15N-30N W OF 36W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS.
ASSOCIATED MID/UPPER LEVEL TROUGH IS NOW N 28N WITH THE MEAN
AXIS ALONG 50W. OVER THE FAR E ATLC...UPPER LEVEL LOW IS
CENTERED W OF THE CANARY ISLANDS NEAR 27N21W WITH A TROUGH
EXTENDING S OVER THE CAPE VERDE ISLANDS. DIVERGENCE E OF THE
UPPER TROUGH IS ENHANCING SHOWERS/THUNDERSTORMS OVER PARTS OF W
AFRICA WITH SCATTERED MODERATE/STRONG CONVECTION MOVING OFF THE
COAST. IN THE LOW LEVELS...RIDGE AXIS EXTENDS THROUGH 32N29W SW
TO 20N40W. AFRICAN DUST CONTINUES W OFF THE COAST OF MAURITANIA
AND SENEGAL WITHIN 250 NM OF LINE FROM 17N16W SW ACROSS THE CAPE
VERDES TO 12N36W RESULTING IN LIMITATION OF CONVECTION TO S OF
THE ITCZ AXIS.

$$
WALLACE



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