[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011024
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU SEP 01 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
0945 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION LEE IS CENTERED NEAR 31.9N 51.3W MOVING NW
AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE THE
LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT3/WTNT33 KNHC. AN UPPER LOW IS W OF LEE AND
STRONG ENOUGH TO PRODUCE W SHEAR ACROSS THE SYSTEM. THUS...
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS E OF THE CENTER
WITHIN 90 NM OF LINE 30N44W-32N50W.

A BROAD 1009 MB TROPICAL ATLC SURFACE LOW IS CENTERED NEAR
19N44W MOVING WNW 10 KT. AN UPPER LEVEL LOW JUST TO THE SW IS
PRODUCING SW SHEAR OVER THE LOW CENTER...ALBEIT WEAKENING. THUS
THIS SYSTEM IS MOVING INTO A MORE FAVORABLE ENVIRONMENT FOR
DEVELOPMENT INTO A TROPICAL SYSTEM. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION SURROUNDS THE LOW WITHIN 90/120 NM OF LINE
19N41W-21N44W-20N48W.

...TROPICAL WAVES...
A 1009 MB LOW IS ALONG THE ITCZ AXIS NEAR 9N25W MOVING W NEAR 10
KT. THE LOW CENTER IS WELL TO THE E OF THE ASSOCIATED
CONVECTION. NUMEROUS STRONG CONVECTION IS WITHIN A 45 NM RADIUS
OF 9.5N32.5W AND IS EMBEDDED WITHIN SCATTERED MODERATE/STRONG
CONVECTION THAT COVERS THE AREA FROM 5.5N-11N BETWEEN 30W-34.5W.

WEAK CARIBBEAN TROPICAL WAVE IS CENTERED ALONG 81W/82W S OF 20N
MOVING W 10-15 KT. WAVE IS IS BENEATH THE W EDGE OF A MID/UPPER
RIDGE THAT EXTENDS FROM THE CENTRAL ATLC ACROSS THE CARIBBEAN.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE S OF 12N TO
ALONG THE COAST OF PANAMA W OF THE COLOMBIAN COAST TO THE COAST
OF COSTA RICA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 14N17W 9N23W 7N27W 11N40W 9N62W.
SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF AFRICA WITHIN
60 NM OF LINE 15N20W-15.5N17W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS WITHIN 180 NM OF THE AXIS FROM 60W 65W
INCLUDING TRINIDAD...TOBAGO...AND THE S WINDWARD ISLANDS.
SCATTERED CLUSTERS OF SIMILAR CONVECTION ARE FROM 10N-17N
BETWEEN 26W-44W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER HIGH ALONG THE E COAST OF THE UNITED STATES CONTINUES
TO FUNNEL ATLC MOISTURE ACROSS FLORIDA INTO THE E GULF AND
TROPICAL MOISTURE FROM THE CARIBBEAN INTO THE S AND THEN THE W
GULF. THE MID/UPPER TROUGH REMAINS OVER TEXAS AND MEXICO
COVERING THE INLAND AREA WITH STRONG SUBSIDENCE AND DRY AIR.
WEAK SURFACE RIDGING FROM THE W ATLC IS STILL KEEPING THE LOW
LEVELS RELATIVELY DRY. MID/UPPER LEVEL INVERTED TROUGH EXTENDS
FROM THE E BAY OF CAMPECHE INTO THE W GULF NEAR 26N94W PRODUCING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE W GULF S OF
27N W OF 91W INCLUDING THE BAY OF CAMPECHE. UPPER MOISTURE
LEVELS WILL REMAIN HIGH OVER THE GULF FOR THE REMAINDER OF THE
WEEK...EXPECT THE TYPICAL AFTERNOON SHOWERS/THUNDERSTORMS TO
DEVELOP OVER LAND.

CARIBBEAN SEA...
THE MID/UPPER LEVEL TROUGH EXTENDS FROM AN UPPER LOW OVER THE
CAYMAN ISLANDS SW TO THE GULF OF HONDURAS AND NE ACROSS E CUBA
INTO THE W/CENTRAL ATLC. THIS UPPER LOW IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS N OF 18N TO OVER CUBA W OF 74W TO
INLAND OVER THE YUCATAN PENINSULA. AN UPPER LEVEL RIDGE FROM THE
CENTRAL ATLC EXTENDS ACROSS THE LEEWARD ISLANDS NEAR 17N62W S OF
THE ABOVE UPPER TROUGH TO CENTRAL AMERICA NEAR 13N83W COVERING
THE REMAINDER OF THE CARIBBEAN. THIS IS KEEPING MOST OF THE
CARIBBEAN RELATIVELY DRY EXCEPT IN THE SW CARIBBEAN ALONG THE
TROPICAL WAVE AND WHERE THE ITCZ EXTENDS. ALTHOUGH THE UPPER
PATTERN IS EXPECTED TO REMAIN VIRTUALLY THE SAME ALL BUT THE SW
CARIBBEAN WILL DRY OUT OVER THE NEXT DAY OR SO.

ATLANTIC OCEAN...
BROAD UPPER HIGH ALONG E COAST OF THE UNITED STATES CONTINUES TO
PUSH UPPER MOISTURE SW OVER THE W ATLC. MID/UPPER TROUGH EXTENDS
FROM AN UPPER LOW W OF T.D. LEE NEAR 32N54W SW ALONG 25N67W TO
ACROSS E CUBA INTO THE CARIBBEAN. THIS IS GENERATING SCATTERED
MODERATE/ISOLATED STRONG CONVECTION WITHIN 120 NM OF LINE
26N70W-29N64W. MID/UPPER HIGH CENTERED S OF THE ABOVE TROUGH IS
CENTERED NEAR 20N60W WITH AN UPPER RIDGE THAT EXTENDS WSW OVER
THE LEEWARD ISLANDS AND ACROSS THE CARIBBEAN...AND N TO 27N51W.
AT THE SURFACE...A WEAK 1016 MB HIGH IS CENTERED NEAR 23N60W.
ALONG THE N SIDE OF THE RIDGE...SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 120 NM OF LINE 23N57W-28N50W. STRONG
SUBSIDENCE/DRY UPPER AIR IS OVER THE TROPICAL ATLC ROUGHLY FROM
10N-20N BETWEEN 48W-70W. THE E ATLC IS DOMINATED BY A SECOND
BROADER UPPER HIGH CENTERED W OF THE CAPE VERDE ISLANDS NEAR
18N35W WITH FLOW COVERING THE AREA S OF 28N E OF 43W. AT THE
SURFACE...SUBTROPICAL RIDGE COVERS THE E ATLC N OF 22N E OF 45W
WITH A 1021 MB HIGH NEAR 33N31W.

$$
WALLACE



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