[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAR 16 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 6N10W 3N20W CROSSING THE EQUATOR AT
38W AND INTO NE BRAZIL NEAR 3S46W. THE ITCZ IS PRETTY ACTIVE
THIS EVENING WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ALONG THE AXIS AND WITHIN 50 NM N OF THE AXIS FROM
14W-22W...AND FROM 32W-38W. SIMILAR CONVECTION IS OVER NE
BRAZIL. CLUSTERS OF STRONG CONVECTION ARE SEEN OVER SW AFRICA...
PARTICULARLY OVER LIBERIA AND FROM 1N-4N BETWEEN THE PRIME
MERIDIAN AND 8W.

...DISCUSSION...

GULF OF MEXICO...
A SHARP UPPER LEVEL TROUGH EXTENDS FROM THE GREAT LAKES REGION
TO LOUISIANA...CLIPPING THE N GULF WATERS. AS OF 21Z...THE
ATTENDANT COLD FRONT STRETCHES FROM THE FLORIDA PANHANDLE TO THE
TEXAS COAST NEAR 28N96W. MOST OF THE CONVECTIVE ACTIVITY IS
ASSOCIATED WITH A PRE-FRONTAL TROUGH THAT CROSSES NORTH-CENTRAL
FLORIDA AND CONTINUES OVER THE SE GULF ALONG 24N85W TO THE
YUCATAN PENINSULA. MOSAIC DOPPLER RADAR FROM THE SE US SHOWS A
NARROW BAND OF SHOWERS WITH EMBEDDED TSTMS MOVING ACROSS LAKE
OKEECHOBEE WHILE OTHER CELLS ARE DEVELOPING OVER SOUTH FLORIDA.
A WELL DEFINED SHORT-WAVE TROUGH MOVING AROUND THE BASE OF THE
LONG WAVE TROUGH MENTIONED ABOVE IS ENHANCING THIS CONVECTION
THAT IS ALSO AFFECTING THE SE GULF AND PARTS OF CUBA. THE COLD
FRONT IN THE NRN GULF IS ANTICIPATED TO PUSH SE AND MERGE WITH
THE PRE-FRONTAL TROUGH ACROSS FLORIDA TONIGHT. THE FRONT IS
FORECAST TO CLEAR SOUTH FLORIDA JUST AFTER MIDNIGHT REACHING THE
NW BAHAMAS AND W CUBA AFTERWARDS. INCREASE IN WINDS AND SEAS IS
EXPECTED IN THE WAY OF THE FRONT TONIGHT THROUGH SAT NIGHT...
THEN SUBSIDING ACROSS MUCH OF THE GULF EXCEPT THE SE PORTION SAT
NIGHT AND SUNDAY. BEHIND THE FRONT...HIGH PRES WILL GRIP THE
GULF AND THE STATE OF FLORIDA  WITH A COLD AND DRY AIRMASS.

CARIBBEAN...
AS MENTIONED IN THE GULF SECTION...A SHORT-WAVE TROUGH WITH THE
AXIS ACROSS W-CENTRAL CUBA AND THE NW CARIBBEAN IS SUPPORTING
THE DEVELOPMENT OF SCATTERED SHOWERS AND TSTMS OVER THE YUCATAN
PENINSULA...PARTS OF CUBA/JAMAICA AND COASTAL WATERS...AND THE
NW CARIBBEAN INCLUDING ALSO NE HONDURAS. THIS TROUGH COVERS MUCH
OF THE W AND CENTRAL CARIBBEAN WHILE THE WRN PERIPHERY OF A
BROAD RIDGE DOMINATES THE REMAINDER OF THE BASIN. STRONG SWLY
WINDS ASSOCIATED WITH THIS RIDGE ARE ADVECTING SOME UPPER LEVEL
MOISTURE/HIGH CLOUDS FROM N SOUTH AMERICA TO THE E CARIBBEAN
INTO THE TROPICAL NORTH ATLC. TYPICAL PATCHES OF LOW LEVEL
MOISTURE ARE FOUND ACROSS THE AREA...ESPECIALLY OVER HISPANIOLA.
TRADE WINDS HAVE SLACKEN IN THE WRN CARIB AS LOW PRES IS LOCATED
N OF THE AREA BUT REMAIN MODERATE TO FRESH ACROSS THE CENTRAL
AND ERN PARTS. LOOKING AHEAD...A COLD FRONT IS EXPECTED TO PUSH
INTO THE REGION TONIGHT INCREASING THE CHANCE OF SHOWERS AS IT
PROGRESSES EWD AND WEAKENS. DRIER AND SLIGHTLY COOLER WEATHER
WILL FOLLOW ADVECTED BY MODERATE TO STRONG NLY WINDS.

WESTERN AND CENTRAL ATLANTIC...
A BAND OF SHOWERS AND TSTMS IS MOVING ACROSS THE NW CORNER OF
THE FORECAST AREA AND IS RELATED TO A PRE-FRONTAL TROUGH MOVING
ACROSS SOUTH-CENTRAL FLORIDA AND THE SE GULF. A COLD FRONT
ENTERS THE REGION NEAR 32N45W AND EXTENDS TO 25N49W THEN
CONTINUES AS A SFC TROUGH TO JUST N OF PUERTO RICO. THE SAN JUAN
DOPPLER RADAR SHOWS ISOLATED TO SCATTERED SHOWERS ASSOCIATED
WITH THIS FEATURE. A 1025 MB HIGH IS LOCATED NE OF BERMUDA. THIS
SYSTEM IS MOVING EWD AHEAD OF A COLD FRONT/PRE-FRONTAL TROUGH
EMERGING OFF THE SE COAST/FLORIDA PENINSULA. ALOFT... MAINLY
ZONAL FLOW DOMINATES THE AREA.

EASTERN ATLANTIC...
THE WEATHER PATTERN REMAINS QUIET WITH STRONG RIDGING BOTH AT
THE SFC AND ALOFT DOMINATING MOST OF THE REGION. THERE ARE SOME
HIGH CLOUDS...DEBRIS MOISTURE FROM THE COLD FRONT IN THE CENTRAL
ATLC...STREAMING ACROSS THE RIDGE AXIS BUT MUCH OF THE AREA IS
VOID OF PRECIP. AN UPPER LOW IS SPINNING JUST WEST OF THE
MADEIRA ISLANDS WITH AN UPPER TROUGH EXTENDING SOUTH TO NEAR THE
CAPE VERDE ISLANDS. THIS LOW WILL MOVE MAINLY S ENTERING THE
FORECAST AREA ON MONDAY. A JETSTREAM BOUNDS THE S PERIPHERY OF
THE TROUGH ADVECTING UPPER LEVEL MOISTURE ACROSS AFRICA. DRY
AIR...RESULTING IS MODERATE TO STRONG SUBSIDENCE IS OBSERVED ON
WV IMAGERY E OF 25N FROM 14N-25N. THE SFC RIDGE IS PRODUCING A
LARGE AREA OF MODERATE TO STRONG WINDS ACROSS THE REGION. THIS
RIDGE IS EXPECTED TO SHIFT SWD TIGHTENING THE PRES GRAD WHICH
WILL INCREASE THE WINDS FURTHER ESPECIALLY N OF 22N LATE THIS
WEEKEND.

$$
GR





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