[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041053
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE 04 JAN 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
1015 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N10W 7N17W 4N26W 6N44W 4N56W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 75/90 NM OF LINE
3N23W-3N31W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 60/75 NM OF LINE 3N31W-9N42W.

...DISCUSSION...

GULF OF MEXICO AND W ATLANTIC...
BROAD MID/UPPER LEVEL RIDGE AXIS EXTENDS FROM A MID/UPPER HIGH
LOCATED IN THE SE GULF OF MEXICO NEAR 24N93W TO OVER THE E
UNITED STATES BEYOND 32N84W. ANTICYCLONIC FLOW COVERS ALL OF THE
GULF AND THE W ATLC W OF 74W. THIS IS PRODUCING STRONG
SUBSIDENCE AND DRY UPPER AIR ACROSS THE GULF S OF 25N AND ACROSS
THE W ATLC S OF 28N. AT THE SURFACE...HIGH PRESSURE COVERS THE W
ATLC WITH A RIDGE AXIS EXTENDING N OF BERMUDA WSW TO A 1029 MB
HIGH NEAR 32N73W TO OVER THE SE UNITED STATES TO NEAR 30N93W.
EMBEDDED WITHIN THIS FLOW...A WEAK SURFACE TROUGH EXTENDS FROM
21N71W 26N71W TO 30N70W. ISOLATED LOW LEVEL SHOWERS DOT THE GULF
MAINLY OFF THE NE MEXICAN/TEXAN COAST AND IN THE STRAITS OF
FLORIDA. SCATTERED AREAS OF FOG ARE REPORTED ALONG THE COAST OF
MEXICO N VERACRUZ TO ALONG THE N GULF COAST OVER THE FLORIDA
PANHANDLE. THE UPPER RIDGE HAS BEGUN TO SHIFT EASTWARD TO OVER
THE W ATLC AND AN UPPER TROUGH IS MOVING TOWARD THE MISSISSIPPI
VALLEY. THE FRONT WILL ENTER THE GULF WEDNESDAY NIGHT INTO
THURSDAY MORNING.

CENTRAL ATLANTIC INTO THE CARIBBEAN...
AREA CONTINUES TO BE CONTROLLED BY A DEEPENING UPPER LEVEL
TROUGH WITH AN AXIS EXTENDING FROM 500 NM E OF BERMUDA NEAR
32N55W SW ACROSS HISPANIOLA INTO THE CARIBBEAN TO OVER CENTRAL
AMERICA NEAR COSTA RICA. VERY STRONG SUBSIDENCE AT THE BASE OF
THE TROUGH COVERS THE CARIBBEAN W OF 70W AND IS PRODUCING VERY
DRY AIR ALOFT. MODERATE SUBSIDENCE COVERS THE REMAINDER OF THE
CENTRAL ATLC W OF 50W AND THE E CARIBBEAN W OF 60W. AN UPPER
LEVEL LOW IS ON THE UPSLOPE SIDE OF THE MID/UPPER TROUGH NEAR
30N47W WITH A SURFACE 1009 MB GALE CENTER LOCATED NEAR 27N49W
WITH A SURFACE TROUGH EXTENDING S ALONG 22N49W TO 16N53W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 27N FROM
47W-50W AND N OF 23N FROM 38W-43W. THE UPPER TROUGH WILL REMAIN
NEARLY STATIONARY OVER THE CENTRAL ATLC DURING THE NEXT 48 HOURS
BUT WILL WEAKEN ACROSS THE CARIBBEAN. THE SURFACE GALE CENTER
WILL CONTINUE TO WEAKEN OVER THE SAME PERIOD.

EAST ATLANTIC...
VERY BROAD MID/UPPER LEVEL RIDGE COVERS THE TROPICAL ATLANTIC S
OF 24N FROM THE CAPE VERDE ISLANDS TO THE LESSER ANTILLES WITH
AN UPPER LEVEL HIGH LOCATED NEAR 8N42W. A SUBTROPICAL JET WITH
WINDS OF 80 TO 100 KT IS ALONG THE N SIDE OF THIS CIRCULATION
ADVECTING HIGH LEVEL MOISTURE FROM NE SOUTH AMERICA TO W OF THE
CAPE VERDE ISLANDS BETWEEN 8N-20N. A WEAK SURFACE TROUGH IS IN
THE W TROPICAL ATLC ALONG 44W/45W FROM 6N-15N. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-15N BETWEEN
39W-46W. AN UPPER LEVEL HIGH OVER AN UPPER LOW PATTERN IS IN THE
NE ATLC WITH THE HIGH CENTERED N OF THE REGION ABOUT 450 NM NNW
OF THE CANARY ISLANDS AND THE LOW APPROACHING THE COAST OF
AFRICA NEAR 24N15W. AT THE SURFACE...A RIDGE AXIS EXTENDS FROM
BEYOND 32N23W SW TO 18N42W. THE BROAD UPPER RIDGE OVER THE
TROPICAL ATLC WILL REMAIN NEARLY STATIONARY OVER THE NEXT 48
HOURS AS THE PATTERN OVER THE NE WILL CONTINUE TO ROTATE TO AN
EAST/WEST ALIGNMENT AND THE SURFACE RIDGE WILL GRADUALLY BEGIN
TO WEAKEN.

$$
WALLACE



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