[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301138
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON OCT 30 2006

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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 57W/58W S OF 14N MOVING W
NEAR 10 KT. SCATTERED SHOWERS AND TSTMS ARE AHEAD OF THE WAVE
AXIS OVER THE SOUTHERN WINDWARD ISLANDS.

A STRONG TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 76W
SOUTH OF 21N MOVING W NEAR 15 KT. DISORGANIZED SHOWER ACTIVITY
COVERS MUCH OF THE CENTRAL AND WESTERN CARIBBEAN SEA AND
ADJACENT LAND AREAS. TROPICAL CYCLONE FORMATION IS NOT
EXPECTED...ALTHOUGH LOCALLY HEAVY RAINS ARE POSSIBLE THROUGHOUT
THE AREA. THIS WAVE IS INTERACTING WITH A FRONTAL SYSTEM THAT
CROSSES CENTRAL BAHAMAS AND EASTERN CUBA. SCATTERED PATCHES OF
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 15N-20N BETWEEN
74W-80W. ONE OF THESE PATCHES IS BETWEEN EASTERN CUBA AND
JAMAICA.

A TROPICAL WAVE IS MAINLY INLAND ALONG 84W S OF 16N MOVING W 15
TO 20 KT. THE WAVE IS GENERATING SCATTRED SHOWERS WITH EMBEDDED
TSTMS OVER THE CARIBBEAN PLAINS OF NICARAGUA AND ADJACENT
COASTAL WATERS. SCATTERED MODERATE CONVECTION IS OVER THE NW
CARIBBEAN.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 9N30W 7N40W 6N50W 6N56W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-13N
EAST OF 26W. SIMILAR CONVECTION IS WITHIN 60-80 NM ON EITHER
SIDE OF THE AXIS BETWEEN 37W-50W.

...DISCUSSION...
THE GULF OF MEXICO...
A SURFACE RIDGE ANCHORED ON A 1022 MB HIGH OVER SE GEORGIA COVERS
THE ENTIRE GULF OF MEXICO AND THE SE OF U.S. INCLUDING THE STATE
OF FLORIDA. A VERY DRY AIR MASS DOMINATES THE AREA. ONLY COLD
AIR STRATOCUMULUS CLOUDS ARE SEEN OVER THE GULF. IN THE UPPER
LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER THE GULF
GIVING THE AREA MOSTLY WLY FLOW. THE SURFACE HIGH PRESSURE WILL
MOVE EAST AND THE RIDGE WILL PERSIST OVER THE N GULF DURING THE
NEXT FEW DAYS. 15-20 KT SLY RETURN FLOW IS ALREADY IN PLACE OVER
THE WESTERN GULF.

THE CARIBBEAN SEA...
THE MAIN WEATHER MAKER OVER THE AREA IS THE INTERACTION BETWEEN
A FRONTAL BOUNDARY OVER EASTERN CUBA AND A TROPICAL WAVE ALONG
76W. THESE TWO FEATURES ARE PRODUCING A LARGE AREA OF SHOWERS
WITH EMBEDDED TSTMS OVER THE CENTRAL AND WEST CARIBBEAN. IN THE
UPPER LEVELS...SWLY FLOW IS OVER THE W CARIBBEAN W OF 80W. AN
UPPER LEVEL HIGH IS OVER HISPANIOLA NEAR 20N71W. A DIFFLUENT
PATTERN ALOFT IS SUPPORTING THE SHOWER/TSTM ACTIVITY ASSOCIATED
WITH THE TROPICAL WAVE/FRONT. 15-20 KT TRADE WINDS WILL BLOW
ACROSS THE BASIN EAST OF 75W. UNDER THE ELY FLOW...PATCHES OF
LOW LEVEL MOISTURE ARE MOVING ACROSS THE LEEWARD/VIRGIN ISLANDS
AND PUERTO RICO. THE SAN JUAN DOPPLER RADAR SHOWS SCATTERED
SHOWERS AND ISOLATED TSTMS OVER THESE ISLANDS AND LOCAL WATERS.
N TO NE WINDS ARE OBSERVED OVER THE NW CARIBBEAN AND WESTERN
CUBA.

THE ATLANTIC OCEAN...
A COLD FRONT ENTERS THE AREA NEAR 31N59W...THEN CONTINUES SW TO
26N69W. A STATIONARY FRONT EXTENDS FROM THIS POINT ACROSS THE
CENTRAL BAHAMAS AND EASTERN CUBA. CLUSTERS OF SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION ARE FROM 23N-28W BETWEEN 66W-71W.
A 1022 MB IS BEHIND THE FRONT NEAR 31N75W COVERING THE W ATLC
AND THE FLORIDA PENINSULA. THE GFS MODEL DEVELOPS A SURFACE LOW
ALONG THE FRONTAL BOUNDARY JUST EAST OF THE BAHAMAS. INCREASED
PRESSURE GRADIENT BETWEEN THE LOW AND THE SURFACE HIGH MENTIONED
ABOVE THAT IS FORECAST TO MOVE NEWD WILL PRODUCE STRONG NE WIND
OVER W ATLC WEST OF 70W BEGINNING TONIGHT. ANOTHER COLD FRONT IS
OVER THE E ATLANTIC ALONG 31N24W 23N35W 22N45W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 70-90 NM AHEAD OF
THE FRONT FROM 25N-31N. IN BETWEEN THESE FRONTAL SYSTEMS THERE
IS A WEAK SURFACE RIDGE. IN THE UPPER LEVELS...A TROUGH IS OVER
THE W ATLANTIC N OF 26N AND W OF 75W. AN UPPER HIGH OVER
HISPANIOLA EXTENDS A RIDGE BETWEEN 60W-75W. ANOTHER UPPER LEVEL
HIGH IS OVER THE CENTRAL ATLANTIC NEAR 25N55W. AN ELONGATED
UPPER LEVEL TROUGH IS OVER THE E ATLANTIC N OF 10N E OF 45W WITH
A STRONG UPPER LEVEL LOW NEAR 32N30W. SWLY WINDS AHEAD OF THIS
TROUGH ARE ADVECTING ABUNDANT UPPER LEVEL MOISTURE ACROSS THE E
ATLC E OF 35W AND THE CAPE VERDE ISLANDS.

$$
GR







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