[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 282338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 28 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N10W 3N28W 2N40W 2N52W. SCATTERED
MODERATE CONVECTION IS WITHIN 60-80 NM N OF THE AXIS BETWEEN 22W
AND 34W. A CLUSTER OF MODERATE TO STRONG CONVECTION IS INLAND
OVER SW AFRICA NEAR 8N10W. CLUSTERS OF SIMILAR CONVECTION ARE
ALONG THE NE COAST OF BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
A DYING COLD FRONT CONTINUES TO MOVE SOUTH ACROSS SOUTH FLORIDA
GENERATING SCATTERED SHOWERS OVER THE MIAMI-DADE COUNTY. A
MID/UPPER TROUGH MOVING OVER THE EASTERN US CLIPS THE NE GULF
WATERS AND SUPPORTS THIS WEAK FRONTAL BOUNDARY THAT ENTERS THE
DISCUSSION AREA NEAR 31N76W. A RIDGE DOMINATES THE REMAINDER OF
THE GULF WITH NEARLY ZONAL FLOW. THIS RIDGE CONTINUES TO PUMP
TROPICAL MOISTURE OVER THE GULF AND NORTH-CENTRAL FLORIDA BUT IS
PRODUCING MAINLY SCATTERED HIGH CLOUDS.  A DIFLUENT PATTERN
ALOFT IS ENHANCING SOME SHOWER/TSTM ACTIVITY ACROSS THE EASTERN
SIERRA MADRE MOUNTAINS IN MEXICO. SURFACE RIDGE CONTINUES TO
BUILD ACROSS THE GULF ANCHORED BY A 1022 MB HIGH OVER LOUISIANA
AND THE NORTHERN GULF. THIS FEATURE WILL BE IN CONTROL OF THE
WEATHER PATTERN ACROSS THE GULF DURING THE NEXT FEW DAYS AS IT
MOVES E ACROSS THE SE US. MOSTLY LIGHT WINDS ARE CURRENTLY
BLOWING ACROSS THE GULF.

CARIBBEAN SEA...
SHORTWAVE UPPER TROUGH OVER THE W ATLC DIPS INTO THE N CARIBBEAN
THROUGH HISPANIOLA WHERE IS GENERATING SOME SHOWER ACTIVITY. AN
UPPER RIDGE STRETCHES E TO W ACROSS NORTHERN SOUTH AMERICA AND
CENTRAL AMERICA THEN EXTENDS N OVER THE W CARIBBEAN INTO CUBA
AND THE BAHAMAS. THIS RIDGE IS GIVING THE AREA SOUTH OF 16N
MOSTLY ZONAL FLOW. IT IS ALSO ADVECTING TROPICAL MOISTURE ACROSS
PANAMA AND COSTA RICA. THIS COMBINED WITH THE CLOSE PROXIMITY OF
THE EPAC ITCZ IS PRODUCING CLUSTERS OF MODERATE CONVECTION
MAINLY NEAR THE COLOMBIA/PANAMA BORDER AND OVER WESTERN PANAMA.
TRADE WIND SHOWERS...CHARACTERIZED BY THEIR SHORT DURATION AND
LIGHT INTENSITY ARE MOVING ACROSS THE LESSER ANTILLES INTO THE E
CARIBBEAN. THESE SHOWERS ARE ALSO AFFECTING PUERTO RICO AND THE
US/UK VIRGIN ISLANDS. MODERATE TO STRONG ELY WINDS DOMINATES THE
BASIN.

ATLANTIC...
SHORTWAVE TROUGH IS OVER THE W ATLC BETWEEN 63W-70W. A SFC
TROUGH...REFLECTION OF THIS FEATURE IS ANALYZED ON THE 18
Z MAP ALONG 65/66W FROM 24N-29N. A SWIRL OF LOW/MID CLOUDS IS
SEEN ON VIS SAT IMAGERY ASSOCIATED WITH THESE FEATURES. UPPER
RIDGE COVERING THE CARIBBEAN EXTENDS AN AXIS JUST E OF THE
SHORTWAVE OVER PARTS OF THE W-CENTRAL ATLC. WEAK UPPER TROUGH
ENTERS THE AREA NEAR 30N40W THEN EXTENDS SW TO 20N50W. THIS IS A
RATHER BENIGN FEATURE PRODUCING ONLY WIDELY ISOLATED SHOWERS.
THE REMAINDER OF THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED BY A 1029 MB HIGH WELL N OF THE REGION. PATCHES OF LOW
LEVEL MOISTURE DRIVEN BY MODERATE TO STRONG TRADE WINDS ARE
FOUND UNDER THE INFLUENCE OF THIS RIDGE.

$$
GR





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