[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN NOV 13 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

A STRONG TROPICAL WAVE ALONG 61W/62W S OF 20N IS MOVING W 10 KT
ACROSS THE LEEWARD/WINDWARD ISLANDS. A 1006 MB LOW IS LOCATED
ALONG THE WAVE NEAR THE GRENADINES AROUND 12.5N.  THE LOW
PRESSURE AREA HAS GOTTEN BETTER DEFINED SINCE YESTERDAY WITH
SEVERAL WINDS REPORTED FROM A WLY DIRECTION S OF THE LOW IN THE
WINDWARD ISLANDS W TO NEAR MARGARITA ISLAND.  HOWEVER WLY SHEAR
IS DISPLACING MOST OF THE SIGNIFICANT TSTMS TO THE E WITH
SCATTERED MODERATE CONVECTION FROM TRINIDAD TO MARTINIQUE
BETWEEN BARBADOS AND THE GRENADINES.  MODERATE WLY SHEAR SHOULD
CONTINUE FOR THE NEXT COUPLE OF DAYS NEAR THE LOW... WHICH
SHOULD PREVENT ANY RAPID TROPICAL CYCLONE DEVELOPMENT.  HOWEVER
ANY SIGNIFICANT CONVECTIVE ORGANIZATION COULD LEAD TO TROPICAL
CYCLONE FORMATION WITHIN THE NEXT 36 HOURS... WITH COMPUTER
MODELS SUGGESTING LIGHTER SHEAR POSSIBLY IN THE SYSTEM'S PATH.

...TROPICAL WAVES...

WEST/CENTRAL CARIBBEAN TROPICAL WAVE ALONG 79W S OF 16N MOVING W
10-15 KT.  IT REMAINS DIFFICULT TO PLACE THE WAVE BUT LONG-TERM
SATELLITE LOOPS SUGGEST THAT IT IS ON THE WESTERN END OF A LARGE
AREA OF DISTURBED WEATHER OVER THE CENTRAL CARIBBEAN.  ISOLATED
SHOWERS/TSTMS ARE FROM 12N-16N BETWEEN 68W-80W.. WITH A CLUSTER
NEAR 13N79.5W PROBABLY CLOSER TO THE WAVE AXIS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 7N25W 4N45W 14N57W.  ISOLATED
MODERATE CONVECTION IS FROM 6N-11N BETWEEN 20W-26W AND WITHIN 60
NM OF ITCZ FROM 34W-57W.

...DISCUSSION...

GULF OF MEXICO...
PLEASANT WARM WEATHER COVERS THE DEEP SOUTH WITH RECORD HEAT IN
PLACES ACROSS THE W GULF.  SLY WINDS ARE TRANSPORTING WARM HUMID
AIR NORTHWARD NW OF A SURFACE RIDGE AXIS RUNNING FROM NE FLORIDA
INTO NE MEXICO.  A FEW TSTMS HAVE BROKEN OUT OVER SE LOUISIANA
WITH THE UNUSUAL INSTABILITY.  OTHERWISE THE ONLY OTHER
SIGNIFICANT WEATHER IS CONCENTRATED AROUND TWO WEAK LOW-LEVEL
TROUGHS...WITH ISOLATED SHOWERS/TSTMS WITHIN 45 NM OF THE TROUGH
AXES RUNNING FROM 22N92W 25.5N92.5W AND 23.5N88W 27N89W.  MOSTLY
SW WINDS AT UPPER LEVELS ARE OVER THE REGION... AROUND A HIGH
OVER S FLORIDA.  CIRRUS CLOUDS SHOULD BE ON THE INCREASE IN THE
NW GULF AS PACIFIC MOISTURE GETS ADVECTED ACROSS TEXAS AND
MEXICO.  NO LARGE CHANGES ARE EXPECTED UNTIL A STRONG COLD FRONT
ENTERS THE AREA LATE TUE NIGHT... LIKELY BRINGING A SQUALL LINE
THROUGH THE REGION.  IN ADDITION WINDS NEAR GALE FORCE ARE
POSSIBLE OVER THE SW GULF AND ONLY A LITTLE LOWER IN THE NW
GULF.

CARIBBEAN...
UPPER TROUGH EXTENDS FROM SE CUBA TO THE YUCATAN PENINSULA WITH
STRONG WLY WINDS OVER MOST OF THE AREA.  THESE WINDS ARE
SLACKENING A LITTLE IN THE SOUTHERN CARIBBEAN S OF 14N AS UPPER
RIDGING BUILDS IN THE AREA.. ORIENTED FROM NW COLOMBIA TO
NICARAGUA.  A LITTLE RIDGING IS ALSO PRESENT IN THE SE CARIBBEAN
BUT IS MOST PRONOUNCED IN THE SW CARIBBEAN.  DIFFLUENT FLOW
ALONG WITH PLENTIFUL MOISTURE AND WEAK TROPICAL WAVES ARE
PRODUCING ISOLATED TSTMS OVER THE CENTRAL AND W CARIBBEAN S OF
15N W OF 70W AND EXPECTED TO CONTINUE FOR MOST OF THE WEEK.  IT
LOOKS QUITE WET FOR THE E CARIBBEAN AS DEEP MOISTURE BEHIND A
TROPICAL WAVE ENTERS THE REGION WITH UPPER SUPPORT FOR HEAVY
RAIN AND ISOLATED FLOODING.  MODELS SUGGEST THAT THE THREAT WILL
EVOLVE FROM THE WINDWARD ISLANDS DURING THE NEXT DAY OR TWO INTO
THE LEEWARD ISLANDS AND PUERTO RICO TUE AND BEYOND.  HOW MUCH
RIDGING DEVELOPS IN THE CENTRAL CARIBBEAN IS CRITICAL TO THE
FUTURE OF THE DISTURBANCE IN THE SE CARIBBEAN... WITH SOME
MODELS INDICATING LESS SHEAR/MORE RIDGING AS EARLY AS TUE BUT
SOME SUGGEST CONDITIONS WON'T BECOME FAVORABLE UNTIL THU.

ATLANTIC OCEAN...
THE UPPER PATTERN IS COMPRISED OF RIDGE/TROUGH/RIDGE/TROUGH
THROUGH THE AREA... WITH THE FIRST RIDGE COVERING THE W ATLC W
OF 70W DUE TO AN UPPER HIGH OVER S FLORIDA.  SCATTERED TO
OCCASIONALLY BROKEN STRATOCUMULUS ARE ACROSS THE REGION EASTWARD
ACROSS THE ATLC EXCEPT NEAR A COLD FRONT FROM THE CENTRAL ATLC
ALONG 32N48W 24N54W 21N65W STATIONARY TO NEAR THE WINDWARD
PASSAGE.  LIFT/DIVERGENCE FROM A SHARP UPPER TROUGH IS CAUSING
SCATTERED MODERATE CONVECTION FROM 24N-31N BETWEEN 45W-50W.
FARTHER E... MID/UPPER RIDGE EXTENDS FROM THE TROPICAL ATLC NEAR
12N56W NE TO BEYOND 32N42W... WITH OVERCAST CIRRUS WITHIN 180 NM
E AND 420 NM W OF THE RIDGE AXIS.  COMPLEX UPPER TROUGH IS IN
THE NE ATLC WITH UPPER LOWS EMBEDDED WITHIN THE TROUGH NEAR
22N33.5NW AND 25N22W.   MEAN TROUGH LIES FROM 30N27W TO 10N34W.
ISOLATED COLD-AIR INSTABILITY TSTMS ARE WITHIN 90 NM OF 19N34W
WITH OTHER ISOLATED SHOWERS/TSTMS IN A DIVERGENT REGION IN THE
SE PORTION OF THE TROUGH FROM 11N-15N W OF THE CAPE VERDES
BETWEEN 26W-30W.  OTHERWISE STRONG HIGH PRESSURE CONTROLS THE E
ATLC WITH NEAR OR ABOVE AVERAGE TRADES E OF 50W.

$$
BLAKE

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