[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131757
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI OCT 13 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 38W SOUTH OF 20N MOVING W NEAR 10
KT. A 1010 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 13 N.
LATEST SATELLITE PICTURES SHOWS THIS AREA OF LOW PRESSURE HAS
WEAKENED DUE TO STRONG UPPER-LEVEL WINDS. SCATTERED MODERATE
CONVECTION IS FROM 14N-18N BETWEEN 35W-39W.

A TROPICAL WAVE IS ALONG 70W SOUTH OF 20N MOVING WEST 10-15 KT.
THIS WAVE HAS LEFT BEHIND A 1008 MB LOW PRESSURE CENTER WHICH IS
CURRENTLY NEAR 22N65W OR A COUPLE OF HUNDRED MILES NORTH-
NORTHEAST OF PUERTO RICO. THIS SYSTEM CONTINUES TO SHOW LITTLE
CHANGE IN ORGANIZATION THIS MORNING...AND UPPER-LEVEL WINDS
CONTINUE TO BECOME LESS CONDUCIVE FOR TROPICAL DEVELOPMENT.
LINES OF LOW CLOUDS WITH EMBEDDED SHOWERS ASSOCIATED WITH THE
CIRCULATION OF THE SURFACE LOW ARE APPROACHING TO THE NORTHERN
COAST OF PUERTO RICO AND HISPANIOLA.

A WEAK TROPICAL WAVE IS ALONG 85W/86W SOUTH OF 22N MOVING WEST
10-15 KT. THIS WAVE IS MOVING THROUGH AN AREA OF AN UPPER LEVEL
RIDGE. MIDDLE TO UPPER LEVEL DRY AIR COVERS THE CARIBBEAN SEA
PRACTICALLY EVERYWHERE WEST OF 70W. NO DEEP CONVECTIVE
PRECIPITATION IS WITH THIS WAVE.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N15W 7N25W 9N35W 8N45W 9N60W.
WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 100/120 NM ON
EITHER SIDE OF THE AXIS WEST OF 35W. SIMILAR CONVECTION IS FOUND
MAINLY SOUTH OF THE AXIS BETWEEN 37W-45. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION ARE INLAND OVER AFRICA FROM 8N-13N
BETWEEN 7W-13W.

...DISCUSSION...
THE GULF OF MEXICO...
DEEP LAYERED TROUGH IS MOVING EASTWARD ACROSS THE EASTERN US. AS
OF 1500 UTC...THE ASSOCIATED COLD FRONT CROSSES NORTHERN FLORIDA
AND THE NORTHERN GULF WATERS TO A 1011 MB SURFACE LOW LOCATED
NEAR 28N94W. THIS LOW HAS FORMED ALONG THE FRONT OVER THE NW
CORNER OF THE GULF. THE FRONT CONTINUES MAINLY WESTWARD ACROSS
NORTHERN MEXICO. DOPPLER RADAR DEPICTS SCATTERED SHOWERS AND
ISOLATED TSTMS ASSOCIATED WITH THE COLD FRONT/LOW OVER THE GULF.
DRY AND COLD CONTINENTAL AIR IS BEHIND THE COLD FRONT. A WEAK
SURFACE TROUGH REMAINS JUST SOUTH OF THE FLORIDA KEYS AND ALONG
THE STRAITS OF FLORIDA GENERATING ISOLATED SHOWERS AND TSTMS. A
WEAKENING FRONTAL TROUGH EXTENDS FROM 31N73W TO OVER NORTH-
CENTRAL FLORIDA WITH ISOLATED SHOWERS. UPPER LEVEL WESTERLY FLOW
COVERS THE GULF WATERS. THIS WESTERLY FLOW IS ASSOCIATED WITH
LARGE-SCALE UPPER LEVEL ANTICYCLONIC LOCATED OVER THE YUCATAN
PENINSULA. THE COLD FRONT WILL MOVE TO THE CENTRAL FLORIDA
PENINSULA TO NE MEXICO TONIGHT AND SHOULD REACH SOUTH FLORIDA
SAT AFTERNOON. MODERATE ELY WINDS OF 20 KT WILL BLOW BEHIND THE
COLD FRONT.

THE CARIBBEAN SEA...
A VERY LARGE UPPER LEVEL ANTICYCLONIC ANCHORED OVER THE YUCATAN
PENINSULA EXTENDS A RIDGE FROM THE SOUTH CENTRAL MEXICO EASTWARD
TO THE GREATER ANTILLES. DRY AIR...RESULTING IN MODERATE TO
STRONG SUBSIDENCE COVERS THE BASIN WEST OF 70W. AN UPPER TROUGH
IN THE W ATLC EXTENDS S INTO THE CARIBBEAN ACROSS PUERTO RICO TO
NEAR LAKE MARACAIBO. SCATTERED SHOWERS ARE OVER THE EASTERN
CARIBBEAN JUST AHEAD THIS UPPER TROUGH. BROAD RIDGE ANCHORED IN
THE TROPICS NEAR 15N57W COVERING MOST OF THE CENTRAL ATLC
INCLUDES THE FAR E CARIBBEAN. LIGHT EASTERLY FLOW IS EXPECTED
ACROSS THE ENTIRE CARIBBEAN DURING THE NEXT SEVERAL DAYS.

THE ATLANTIC OCEAN...
A WEAK LOW PRESSURE AREA IS LOCATED A COUPLE OF HUNDRED MILES
NORTH-NORTHEAST OF PUERTO RICO. THIS SYSTEM IS MOVING SLOWLY
WESTWARD. A BAND OF SCATTERED MODERATE CONVECTION REMAINS EAST
OF THE SURFACE LOW PRESSURE AND COVERS FROM 18N-31N AND BEYOND
BETWEEN 55W-62W. THE VERY LARGE UPPER LEVEL ANTICYCLONIC
ANCHORED OVER THE YUCATAN PENINSULA ALSO DOMINATES THE W ATLC
WEST OF 68W. THE WLY FLOW ASSOCIATED WITH THIS FEATURE IS
ADVECTING UPPER LEVEL MOISTURE OVER THE FLORIDA PENINSULA INTO
THE W ATLC. AN UPPER TROUGH LIES ALONG 64W AND EXTENDS INTO THE
CARIBBEAN ACROSS PUERTO RICO. AN UPPER HIGH CENTERED IN THE
TROPICS NEAR 15N57W EXTENDS A RIDGE NWD ALONG 55W TO BEYOND
31N55W. AN UPPER TROUGH IS OVER THE E ATLC MAINLY NORTH OF THE
AREA. THE ASSOCIATED COLD FRONT IS ENTERING THE REGION ALONG
30/31N BETWEEN 30W-40W. A BAND OF SHOWERS WITH EMBEDDED TSTMS IS
WITHIN 60-100 NM AHEAD OF THE FRONT. AT THE SURFACE A BROAD
SURFACE RIDGE COVERS THE ATLC E OF 60W. A 1021 MB SURFACE HIGH
IS LOCATED OVER THE CANARY ISLANDS. AN AREA OF SCATTERED SHOWERS
AND ISOLATED TSTMS IS FROM 20N-27N BETWEEN 37W-46W ASSOCIATED
WITH A SHORT WAVE TROUGH THAT LIES ALONG 37/38W.

$$
GR




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