[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190554
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 33W S OF 19N MOVING W NEAR 10 KT. SOME
CYCLONIC TURNING IS SEEN ALONG THE WAVE AXIS NEAR 12N. SCATTRED
MODERATE/ISOLATED STRONG CONVECTION IS FROM BETWEEN 31W-35W...
AND FROM 10N-15N BETWEEN 25N-30W. SW SHEAR ESPECIALLY OVER THE
NORTHERN PORTION OF THE WAVE CONTINUES TO STRETCH THE ASSOCIATED
HIGH CLOUDS TO THE NE.

A TROPICAL WAVE IS ALONG 43/44W SOUTH OF 18N MOVING WEST AT
10-15 KT. THE WAVE SHOWS AN INVERTED V SIGNATURE AND DEEP
CONVECTION REMAINS MINIMAL WITH ISOLATED SHOWERS/TSTMS NOTED ON
THE NORTHERN END OF THE WAVE FROM 12N-15N BETWEEN 41W-47W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N16W 10N30W 10N40W 9N46W 7N58W.
OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTRED MODERATE CONVECTION IS FOUND WITHIN AROUND 200
NM SOUTH OF THE AXIS WEST OF 34W. A SMALL CLUSTER OF MODERATE
CONVECTION NOTED NEAR 9N24W.

...DISCUSSION...
GULF OF MEXICO...
A LARGE MID/UPPER RIDGE ANCHORED ON A HIGH LOCATED NORTH OF THE
YUCATAN PENINSULA CONTINUES TO DOMINATE THE ENTIRE GULF AND THE
STATE OF FLORIDA...AS WELL AS THE WEST-CENTRAL CARIBBEAN AND
CENTRAL AMERICA. DRY AIR RESULTING IN MODERATE TO STRONG
SUBSIDENCE COVERS THE AREA. DOPPLER RADAR SHOWS A BAND OF
MODERATE SHOWERS WITH EMBEDDED TSTMS OVER ERN TEXAS AND
LOUISIANA ASSOCIATED WITH THE UNSTABLE ENVIRONMENT S OF A COLD
FRONT. THIS SYSTEM IS EXPECTED TO MOVE OFF THE TEXAS COAST EARLY
TODAY AND EXTEND FROM FLORIDA BIG BEND TO SW GULF EARLY FRIDAY.
NLY WINDS OF 15-20 KT WILL FOLLOW THE COLD FRONT AND INVADE THE
NW CORNER OF THE GULF TODAY. AN ATLC SURFACE RIDGE CURRENTLY
DOMINATES THE REGION WITH SLY WINDS OF 10-15 KT.

CARIBBEAN SEA...
CLOUDINESS AND SHOWERS ASSOCIATED WITH THE LOW PRESSURE AREA
THAT HAS BEEN MEANDERING JUST NORTH OF PUERTO RICO DURING THE
PREVIOUS DAY HAVE INCREASED. HOWEVER...UPPER-LEVEL WINDS ARE NOT
FAVORABLE FOR TROPICAL CYCLONE FORMATION. THE SAN JUAN DOPPLER
RADAR DEPICTS NUMEROUS SHOWERS WITH EMBEDDED TSTMS OVER THE
EASTERN PORTION OF PUERTO RICO AND THE NORTHERN VIRGIN ISLANDS.
ACCORDING TO THE GFS MODEL...THIS FEATURE WILL SLOWLY MOVE NWD
AND AWAY FROM PUERTO DURING THE NEXT FEW DAYS. A SURFACE TROUGH
EXTENDS SSW TO THE ABC ISLANDS FROM THIS 1006MB LOW PRESSURE
AREA. IN THE UPPER LEVELS THE LARGE UPPER HIGH ANCHORED IN THE
GULF OF MEXICO NORTH OF THE YUCATAN PENINSULA EXTENDS A RIDGE
ACROSS THE W-CENTRAL CARIBBEAN WHILE A BROAD UPPER TROUGH
DOMINATES THE EASTERN CARIBBEAN. THIS FEATURE EXTENDS FROM
PUERTO RICO TO NORTHERN COLOMBIA. A DIFFLUENT PATTERN ALOFT IS
SUPPORTING THE DEVELOPMENT OF SCATTERED CLUSTERS OF MODERATE
CONVECTION OVER NORTHERN SOUTH AMERICA THANKS TO THE PRESENCE OF
AN UPPER HIGH OVER THE REGION. ANOTHER WEAK SURFACE LOW PRESSURE
OF 1006 MB IS OVER THE CENTRAL CARIBBEAN NEAR 16N75W. WINDS ARE
LIGHT ACROSS THE BASIN DUE TO A WEAK PRESSURE PATTERN.

ATLANTIC OCEAN...
NLY UPPER FLOW ASSOCIATED WITH THE AFOREMENTIONED LARGE UPPER
RIDGE DOMINATES THE WRN ATLC W OF 68W. A 1018 MB SURFACE HIGH
OVER THE W ATLC NEAR 35N60W EXTENDS A RIDGE SW ACROSS THE
BAHAMAS...CUBA AND THE FLORIDA PENINSULA. AN UPPER TROUGH IS
OVER THE CENTRAL ATLC WITH AN UPPER LOW NEAR 25N58W. THIS SYSTEM
IS GENERATING PATCHES OF MODERATE CONVECTION WITH THE STRONGEST
ONE JUST NEAR THE BASE OF THE THROUGH FROM 16N-18N BETWEEN
55W-58W. AT THE SURFACE...A STATIONARY FRONT ENTERS THE AREA
NEAR 32N48W TO 28N53W. A SURFACE TROUGH EXTENDS FROM THIS POINT
TO THE LOW THAT REMAINS NORTH OF PUERTO RICO. STRONG UPPER WLY
FLOW IS OVER THE TROPICAL NORTH ATLC WATERS E OF THE WINDWARD
ISLANDS S OF THE UPPER ABOVE MENTIONED UPPER LOW. A SHORT WAVE
TROUGH LIES ALONG 40W. EAST OF THIS FEATURE THERE IS A RIDGE
COVERING BETWEEN 20W-35W. A DEEP LAYER TROUGH IS BETWEEN THE
CANARY ISLANDS AND WESTERN AFRICA. A 1018 MB SURFACE HIGH
DOMINATES THE E-CENTRAL ATLC EAST OF 48W.

$$
GR




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