[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 4 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.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N10W 1N20W ALONG THE EQUATOR FROM
24W-42W AND INTO SOUTH AMERICA NEAR 2S48W. SCATTERED MODERATE
CONVECTION IS WITHIN 100 NM OF THE AXIS FROM 18W-24W. CLUSTERS
OF MODERATE TO STRONG CONVECTION ARE ALONG 7W FROM 3S TO 2N.

...DISCUSSION...

GULF OF MEXICO...
A MID/UPPER LEVEL RIDGE DOMINATES THE GULF...WITH THE AXIS
EXTENDING NORTH FROM WRN CUBA THROUGH THE SE US. A SHORT WAVE
TROUGH CONTINUES TO SLOWLY MOVE EWD ACROSS TEXAS AND MEXICO AND
WILL BE ABSORBED BY A LONG WAVE TROUGH OVER THE CENTRAL PLAINS.
IT AXIS LIES ALONG 100W AND IS STILL ENHANCING THE SHOWER/TSTM
ACTIVITY OVER E MEXICO AND PARTS OF TEXAS AND LOUISIANA. THE
MOSAIC DOPPLER RADAR FROM THE SE US SHOWS A BAND OF SHOWERS WITH
EMBEDDED TSTMS OVER THE NW CORNER OF THE GULF N OF 27N BETWEEN
91W-97W WHERE THERE IS A WEAK SFC LOW. ASSOCIATED WITH THE UPPER
TROUGH IS A FRONTAL BOUNDARY. AS OF 2100Z...THE FRONTAL SYSTEM
EXTENDS FROM THE FLORIDA PANHANDLE TO A WEAK 1015 MB SFC LOW
LOCATED NEAR 28N93W ENTERING THE DEEP SOUTH BETWEEN CORPUS
CHRISTI AND BROWNSVILLE CONTINUING OVER NORTHERN MEXICO AS A
STATIONARY FRONT. A WEAK SURFACE RIDGE EXTENDS FROM THE W ATLC
ACROSS THE GULF ANCHORED BY A HIGH JUST NE OF THE BAHAMAS. THE
COLD FRONT WILL MOVE SE ACROSS THE GULF REACHING SOUTH FLORIDA
TOMORROW AFTERNOON. STRONG HIGH PRES WILL FOLLOW THE FRONT
BRINGING AN INCREASE IN WINDS AND SEAS ACROSS THE AREA.

CARIBBEAN SEA...
A BROAD UPPER E/W RIDGE EXTENDS ACROSS THE N PORTION OF SOUTH
AMERICA INTO THE W CARIBBEAN FROM COLOMBIA TO CUBA WITH SW WIND
TRANSPORTING UPPER LEVEL MOISTURE FROM THE E PACIFIC ACROSS
CENTRAL AMERICA INTO THE NW PORTION OF THE CARIBBEAN. MODERATE
TO STRONG SUBSIDENCE AND DRY AIR COVER MUCH OF THE CARIBBEAN
ESPECIALLY E OF 80W. WEAK HIGH PRES N OF THE AREA IS ALLOWING
THE TRADES TO SLACKEN. ELY WINDS OF 15 TO 20 KT ARE FOUND JUST
OFF THE COLOMBIAN COAST. LIGHTER WINDS ARE BLOWING ACROSS THE NW
PORTION OF THE BASIN. TYPICAL FRAGMENTS OF LOW/MID CLOUDS WITH
ISOLATED SHOWERS ARE OVER THE NE CARIBBEAN AND THE GREATER
ANTILLES AS WELL AS OVER PARTS OF CENTRAL AMERICA. CLUSTERS OF
MODERATE TO STRONG CONVECTION ARE OVER NORTHERN COLOMBIA
ASSOCIATED WITH A DIFFLUENT PATTERN ALOFT AND THE TYPICAL LOW
THAT SITS IN THIS AREA. THE COLD FRONT CURRENTLY OVER THE GULF
IS FORECAST TO REACH THE YUCATAN CHANNEL AND WESTERN CUBA ON
FRIDAY.

ATLANTIC OCEAN...
AN UPPER RIDGE/TROUGH/RIDGE PATTERN CONTINUES TO DOMINATE THE
FORECAST AREA. A BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN
INTO THE W ATLC W OF 65W. A WEAK SURFACE RIDGE COVERS THE W ATLC
AND THE FLORIDA PENINSULA. A DEEP LAYERED TROUGH IS IN THE
CENTRAL ATLC N OF 15N FROM 35W-65W. THE ATTENDANT FRONTAL
BOUNDARY EXTENDS SW AND THEN W FROM A 998 MB SFC LOW LOCATED N
OF THE AREA TO 27N60W CONTINUING AS A SURFACE TROUGH TO 29N67W.
THIS SYSTEM WITH GALE FORCE WINDS IS PRODUCING AN INCREASE IN
WINDS AND SEAS OVER THE CENTRAL ATLC N OF 25N BETWEEN 40W-50W.
AN UPPER RIDGE WITH AXIS ALONG 20W COVERS THE REMAINDER OF THE
ATLC. WEAK HIGH PRES RIDGING LIES E OF 40W ANCHORED BY A 1019 MB
HIGH BETWEEN THE CANARY AND MADEIRA ISLANDS NEAR 32N15W.
SATELLITE IMAGERY SHOWS A BROAD BAND OF TRANSVERSE HIGH CLOUDS
ASSOCIATED WITH A TROPICAL JETSTREAM FROM NE VENEZUELA ALL THE
WAY NE TO THE AFRICAN COAST CROSSING N OF THE CAPE VERDE ISLANDS.

$$
GR



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