[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191034
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 34W S OF 19N MOVING W NEAR 10 KT. SOME
CYCLONIC TURNING IS SEEN ALONG THE WAVE AXIS NEAR 13N. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-16N BETWEEN
30W-36W. 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 46W SOUTH OF 18N MOVING WEST NEAR 15
KT. THE WAVE SHOWS AN INVERTED V SIGNATURE WITH ISOLATED SHOWERS
AND TSTMS NOTED ON THE NORTHERN END OF THE WAVE FROM 12N-15N
BETWEEN 40W-46W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N14W 8N25W 12N32W 11N40W 7N58W.
OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION ARE
WITHIN 40 NM SOUTH OF THE AXIS EAST OF 18W. SCATTERED MODERATE
CONVECTION IS FROM 4N-6N BETWEEN 18W-25W.

...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 MOST OF THE AREA. DOPPLER RADAR SHOWS A BAND
OF MODERATE SHOWERS WITH EMBEDDED TSTMS ACROSS ERN TEXAS...
NORTHERN LOUISIANA AND CENTRAL MISSISSIPPI ASSOCIATED WITH THE
UNSTABLE ENVIRONMENT S OF A COLD FRONT. THIS SYSTEM IS EXPECTED
TO MOVE OFF THE TEXAS COAST THIS AFTERNOON AND EXTEND FROM THE
NE GULF TO THE NE MEXICAN COAST ON FRIDAY. NLY WINDS OF 15-20 KT
WILL FOLLOW THE COLD FRONT AND INVADE THE NW CORNER OF THE GULF
LATER TODAY. AN ATLC SURFACE RIDGE CURRENTLY DOMINATES THE
REGION WITH SLY WINDS OF 10-15 KT.

CARIBBEAN SEA...
THE LOW PRESSURE AREA LOCATED NEAR 20N66W OR JUST NORTH OF
PUERTO RICO CONTINUES TO PRODUCE CLOUDINESS AND NUMEROUS
SHOWERS WITH EMBEDDED TSTMS. UPPER-LEVEL WINDS REMAIN
UNFAVORABLE FOR TROPICAL CYCLONE FORMATION. CLUSTERS OF
MODERATE/ISOLATED STRONG CONVECTION ARE MAINLY IS OF THE LOW
PRESSURE CENTER FROM 17N-20N BETWEEN 61W-65W. THIS CONVECTIVE
ACTIVITY IS AFFECTING THE VIRGIN ISLANDS AND THE NORTHERN
LEEWARD ISLANDS...WHERE LOCALLY HEAVY RAIN AND GUSTY WINDS
HAVE BEEN REPORTED. 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 FROM THIS 1006MB LOW PRESSURE
AREA TO LA GUAJIRA PENINSULA WHERE TSTMS FLARE UP EARLY THIS
MORNING. IN THE UPPER LEVELS THE LARGE UPPER HIGH SITUATED 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 TROUGH 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. ANOTHER WEAK SURFACE LOW
PRESSURE OF 1007 MB IS OVER THE CENTRAL CARIBBEAN NEAR 16N74W.
IN GENERAL...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-CENTRAL ATLC NEAR 34N61W 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 25N56W. THIS SYSTEM
IS GENERATING PATCHES OF MODERATE CONVECTION FROM 16N-30N
BETWEEN 50W-55W. AT THE SURFACE...A TROUGH EXTENDS FROM 29N-48W
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 LOW MENTIONED ABOVE. 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 1017 MB SURFACE HIGH DOMINATES THE
E-CENTRAL ATLC EAST OF 45W. ONLY PATCHES OF MAINLY LOW CLOUDS
ARE FOUND UNDER THE INFLUENCE OF THIS SYSTEM THAT REACHES THE
CANARY ISLANDS.

$$
GR





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