[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211104
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 21 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...THE ITCZ...
8N8W 5N12W 3N20W 2N30W 1N40W...CROSSING THE EQUATOR AT 50W...
GOING INTO NORTHEASTERN BRAZIL NEAR 1S52W. SCATTERED STRONG
SHOWERS AND THUNDERSTORMS FROM 3N TO 5N BETWEEN 27W AND 32W...
AND FROM COASTAL BRAZIL NEAR 3S TO 4N BETWEEN 38W AND 47W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDS FROM THE YUCATAN PENINSULA BEYOND
THE SOUTHEASTERN CORNER OF LOUISIANA. THE SURFACE PRESSURE
GRADIENT IN THE GULF OF MEXICO IS WEAK. A SURFACE TROUGH CUTS
THROUGH INTERIOR MEXICO FROM THE ISTHMUS OF TEHUANTEPEC
NORTHWESTWARD THROUGH CENTRAL MEXICO TO NORTH CENTRAL MEXICO.
THE FORECAST FOR THE NEXT 72 HOURS IN THE GULF OF MEXICO IS
FOR EASTERLY SURFACE WINDS AND NO COLD FRONT.

THE CARIBBEAN SEA...
AN UPPER LEVEL RIDGE EXTENDS FROM NORTHERN COLOMBIA/EXTREME
NORTHWESTERN VENEZUELA TOWARD THE NORTHWEST CORNER OF THE
CARIBBEAN SEA...TO THE YUCATAN PENINSULA/YUCATAN CHANNEL.
A DISSIPATING STATIONARY FRONT ENTERS THE AREA FROM THE ATLANTIC
OCEAN THROUGH 20N70W...ACROSS CENTRAL HAITI FROM NORTHEAST-TO-
SOUTHWEST...TO 18N76W JUST EAST OF JAMAICA...TO 14N85W IN NORTH
CENTRAL NICARAGUA NEAR THE BORDER WITH HONDURAS. ISOLATED
MODERATE SHOWERS ARE WITHIN 60 NM ON EITHER SIDE OF THE FRONT.
ISOLATED MODERATE SHOWERS ARE WITHIN 30 NM ON EITHER SIDE OF
18N65W NEAR PUERTO RICO BEYOND 20N60W. A SURFACE RIDGE GOES FROM
THE ATLANTIC OCEAN THROUGH 17N44W TO 10N62W NEAR VENEZUELA AND
TRINIDAD. ISOLATED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS
ARE IN THE COASTAL PLAINS OF VENEZUELA AND COLOMBIA BETWEEN 69W
AND 76W. A WEAK MIDDLE LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
12N93W IN THE EASTERN PACIFIC OCEAN. STRONG SHOWERS AND
THUNDERSTORMS ARE FROM 11N TO 13N BETWEEN 87W AND 88W...AND
FROM 13N TO 14N BETWEEN 88W AND 89W...FROM NICARAGUA TO
EL SALVADOR TO HONDURAS.

THE ATLANTIC OCEAN...
DEEP LAYER CYCLONIC FLOW COVERS THE AREA NORTH OF 20N WEST OF
56W. THIS SYSTEM SUPPORTS AN ATLANTIC OCEAN COLD FRONT THAT
PASSES THROUGH 32N50W TO 25N60W TO 20N70W. A DISSIPATING
STATIONARY FRONT CONTINUES FROM 20N70W TO CENTRAL HAITI.
ISOLATED MODERATE SHOWERS ARE WITHIN 30 NM ON EITHER SIDE OF
25N50W 20N60W TO 18N65W IN THE WATERS JUST EAST OF PUERTO
RICO...AND NORTH OF 26N BETWEEN 39W AND 50W. AN UPPER LEVEL
RIDGE GOES FROM 22N50W TO 27N45W BEYOND 32N40W. A SURFACE RIDGE
STARTS AT A 1022 MB HIGH PRESSURE CENTER NEAR 33N26W AND IT
CONTINUES TO 28N34W 16N43W INTO THE SOUTHEASTERN CARIBBEAN SEA
NEAR 10N62W. MIDDLE TO UPPER LEVEL DRY AIR/ SUBSIDENCE IS WITHIN
300 NM TO 400 NM NORTHWEST OF THE LINE FROM 14N23W NEAR THE CAPE
VERDE ISLANDS TO 8N40W...AND WITHIN 500 NM TO 700 NM OF THE LINE
FROM 8N40W 5N50W 5N55W. A MIDDLE TO UPPER LEVEL TROUGH RUNS FROM
A CYCLONIC CIRCULATION CENTER NEAR 33N10W TO THE NORTHERN PART
OF THE WESTERN SAHARA...TO 20N19W TO 16N23W IN THE EASTERN CAPE
VERDE ISLANDS. SOME UPPER LEVEL WESTERLY FLOW IS SOUTH OF 3N/4N
MOVING FROM NORTHEASTERN SOUTH AMERICA EASTWARD TO 10W. AN UPPER
LEVEL RIDGE...AT A LEVEL DIFFERENT FROM THE AFOREMENTIONED UPPER
LEVEL WESTERLY FLOW...IS ALONG 3N BETWEEN THE PRIME MERIDIAN AND
50W.

$$
MT




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