[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 120509
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU 12 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 34W/35W S OF 13N MOVING W 10-15 KT.
POSITION IS BASED ON LOW CLOUD CYCLONIC SIGNATURE AND
ENHANCEMENT OF ITCZ CONVECTION.

TROPICAL WAVE IS ALONG 55W S OF 13N MOVING W 15 KT. POSITION IS
BASED ON LOW CLOUD CYCLONIC SIGNATURE AND ENHANCEMENT OF ITCZ
CONVECTION.

TROPICAL WAVE IS ALONG 94W IS INLAND OVER S MEXICO AND NO LONGER
IN THE ATLC WATERS. HOWEVER...SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE BEING GENERATED OVER S MEXICO AND THE YUCATAN
PENINSULA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N14W 9N21W 5N30W 3N38W 9N56W 8N62W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
WITHIN 250 NM N OF THE AXIS FROM 28W-34W WITH CLUSTERS OF
SCATTERED MODERATE CONVECTION WITHIN 250 NM S OF THE AXIS FROM
26W-37W...ENHANCED BY THE TROPICAL WAVE. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF THE AXIS FROM
50W-58W...ENHANCED BY THE TROPICAL WAVE.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE DOMINATES THE GULF OF MEXICO WHILE THE UPPER
TROUGH IS MOVING ACROSS FLORIDA INTO THE W ATLC. A MOISTURE
PLUME IS RACING E OVER THE SE GULF S OF 25N FROM 83W-90W
ASSOCIATED BY CONVECTION GENERATED INLAND OVER S MEXICO AND THE
YUCATAN PENINSULA BY THE TROPICAL WAVE ALONG 94W. DRY
CONTINENTAL UPPER AIR IS NOTED OVER THE REMAINDER OF THE GULF
LEAVING THE AREA MOSTLY CLOUD FREE. AT THE SURFACE...WEAK 1017
MB HIGH IS POSITIONED OFF THE N GULF COAST NEAR 29N88W WITH A
WEAK SURFACE TROUGH EXTENDING FROM NE FLORIDA INTO THE NE GULF.
THIS TROUGH IS THE REMNANTS OF THE LOW/TROUGH THAT WAS GENERATED
BY THE UPPER LOW THAT IS NOW IN THE W ATLC. HAZE AND SMOKE FROM
AGRICULTURE FIRES OVER CENTRAL AMERICA AND MEXICO ARE NOTED S OF
24N W OF 90W...BUT IT NOT NEARLY AS DENSE AS THE PAST FEW DAYS.

CARIBBEAN...
UPPER TROUGH EXTENDS S INTO THE N CARIBBEAN FROM THE UPPER LOW
OVER THE W ATLC...ROUGHLY N OF 18N BETWEEN 70W-80W. BROAD UPPER
RIDGING IS NOTED OVER THE E CARIBBEAN EXTENDING W OF 75W INTO
THE TROPICAL ATLC WITH THE AXIS ALONG 60W. OTHERWISE THE UPPER
FLOW IS ZONAL AND ADVECTING DEBRIS MOISTURE FROM THE E PACIFIC
ITCZ EASTWARD ACROSS THE CARIBBEAN AND REINFORCED BY DEBRIS
MOISTURE FROM CONVECTION ASSOCIATED WITH A BROAD AREA OF LOWER
PRESSURE OVER THE SW CARIBBEAN. UPPER DIFFLUENCE E OF THE UPPER
TROUGH IS ENHANCING CONVECTION ALONG A PERSISTENT FRONTAL TROUGH
FROM OVER THE N LEEWARD ISLANDS TO OVER HISPANIOLA. THESE
ENHANCED RAINS WILL LIKELY CONTINUE FOR A FEW MORE DAYS
RESULTING IN A TRAIN ECHOING EFFECT. FLASH FLOODS AND MUDSLIDES
ARE POSSIBLY DOWNSLOPE OF ELEVATED TERRAIN. THE NORTHERN
EXTENSION OF A TROPICAL WAVE WILL LIKELY INCREASE THE CHANCE OF
RAIN OVER THE REMAINDER OF THE LESSER ANTILLES LATER TODAY.

ATLANTIC...
UPPER LOW IS CENTERED IN THE W ATLC NEAR 31N75W WITH A TROUGH
EXTENDING S ACROSS THE BAHAMAS INTO THE N CARIBBEAN. A LARGER
DEEP LAYERED LOW IS CENTERED WELL N OF THE CENTRAL ATLC WITH THE
UPPER TROUGH EXTENDING S INTO THE AREA N OF 25N FROM 43W-63W.
DRY AIR CONTINUES TO DOMINATE THE AREA N OF A LINE FROM CUBA
NEAR 22N78W 26N61W TO 30N47W. LARGE UPPER HIGH IS CENTERED IN
THE TROPICAL ATLC NEAR 10N48W WITH A BROAD RIDGE COVERING THE
AREA FROM THE CAPE VERDE ISLANDS INTO THE CARIBBEAN. AN UPPER
RIDGE AXIS ALSO EXTENDS FROM THE BROAD RIDGE NE TO WELL BEYOND
32N36W. A MOISTURE PLUME IS NOTED WITHIN 350 NM EITHER SIDE OF
LINE FROM THE NE CARIBBEAN NEAR 18N66W NE TO 30N40W. SOME OF
THIS MOISTURE ORIGINATES FROM E PACIFIC ITCZ CONVECTION AND
CONVECTION OVER THE CARIBBEAN. UPPER DIFFLUENCE E OF THE
UPSTREAM TROUGH IS ENHANCING CONVECTION ALONG A PERSISTENT
SURFACE FRONTAL TROUGH EXTENDING FROM 32N49W TO OVER THE N
LEEWARD ISLANDS...WITH DEBRIS MOISTURE MERGING WITH THE PLUME
FROM THE SW. AT THE SURFACE...A RIDGE DOMINATES THE LOWER LEVELS
OF THE ATLANTIC E OF 50W...AND IS SUPPRESSING ANY CONVECTION
OVER THE E ATLC.

$$
WALLACE


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