[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT MAY 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 37W S OF 8N MOVING W 10 KT NOT AS WELL
DEFINED AS 24 HRS AGO. ISOLATED CONVECTION S OF 4N WITHIN 30 NM
OF AXIS.

...ITCZ...
ITCZ AXIS ALONG  6N11W  3N31W  5N37W  6N53W.  CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION WITHIN 180 NM OF AXIS E OF
29W.  MULTIPLE LAYERS OF CLOUDS W OF 37W WITH ISOLATED
CONVECTION MAINLY S OF 8N FROM 38W TO 45W.

...DISCUSSION...
GULF OF MEXICO...
LARGE DEEP LAYERED CYCLONIC VORTEX OVER GREAT LAKES HAS LONGWAVE
UPPER LEVEL TROUGH DIG SW ACROSS TEXAS AND CENTRAL MEXICO INTO E
PAC.  WEAK SURFACE TROUGH REFLECTION ALONG NORTH TEXAS BORDER
DOES NOT APPEAR TO HAVE ENOUGH SUPPORT TO SWEEP SOUTH INTO GULF
OF MEXICO AS PER GFS SOLUTION. UPPER WIND FLOW NOW QUASI-ZONAL
BUT MOST MODELS QUICKLY BRING UPPER LEVEL TROUGH OVER GULF BY
SUN AND E OF FLORIDA BY SUN NIGHT WITH GULF UPPER WIND RETURNING
BECOMING ZONAL.  WATER VAPOR IMAGES HAVE PLENTY OF WATER AT THE
UPPER LEVELS OVER SRN HALF OF GULF WHILE NW QUARTER REMAINS
UNDER DRY SPELL.  LOW PRES CENTER 1004 MB OVER NRN MEXICO AND
LOW PRES 1007 MB OVER E PAC SUPPLYING HIGH LEVEL MOISTURE OVER
GULF OF MEXICO.  GFS MAKES THIS MOISTURE AVAILABLE CONGRUENT
WITH ARRIVAL OF TROUGH IN NW GULF.  CLOUDS AND PRECIPITATION
INCREASING OVER BAY OF CAMPECHE AND EXPECTED TO INCREASE THROUGH
SUN.

HIGH PRES 1014 MB OVER N CENTRAL GULF SLIDES E OF BASIN SUN AND
SUN NIGHT INTO ATLC BY MON.

CARIBBEAN SEA...
WEAK TRADEWINDS CONTINUE ACROSS ENTIRE BASIN AS ATLC HIGH PRES
1016 MB RETREATS E FORCED BY SW N ATLC COLD FRONT.  IN THE UPPER
LEVELS...CARIBBEAN REMAINS UNDER BROAD RIDGE CENTERED OVER
PANAMA/COSTA RICA BORDER.  SOUTHEASTERN PERIPHERY OF RIDGE HAS
PROMPTED SCATTERED SHOWERS/ISOLATED TSTMS INLAND COLOMBIA AS
EQUATORIAL TROUGH EXTENDS FROM LOW PRES 1009 MB WESTWARD TO LOW
PRES OVER E PAC.  UPPER TROUGH IN CENTRAL ATLC DIPS SW ACROSS
TROPICAL ATLC AND EXTREME ERN CARIBBEAN INCLUDING LESSER
ANTILLES.  DRY UPPER AIR AND MODERATE/STRONG SUBSIDENCE COVERS
AREA E OF 75W SUPPRESSING ANY SHOWER ACTIVITY.  SCATTERED
CONVECTION OVER YUCATAN PENINSULA DECREASING AT THIS TIME AS LOW
PRES OVER MEXICO WEAKENS AND DRIFTS N.

ATLANTIC OCEAN...
DEEP LAYERED TROUGH PREVIOUSLY OVER SW N ATLC HAS SHIFTED NE
PULLING UPPER SUPPORT OF WEAK COLD FRONT PRESENTLY FROM 31N71W
ACROSS NE BAHAMAS TO WRN CUBA.  CLOUDINESS AND ISOLATED
CONVECTION WITHIN 30 NM OF FRONTAL BOUNDARY WHILE MULTILAYERED
CANOPY N OF 29N ASSOCIATED WITH UPPER TROUGH.  MODERATE AIR
MASS CONFLUENCE AT UPPER LEVELS PROMPTING STRONG SUBSIDENCE
BEHIND FRONTAL BOUNDARY RESULTING IN VERY DRY AIR MASS.

BROAD DEEP LAYERED TROUGH OVER CENTRAL/EAST ATLC N OF 18N FROM
44-60W.  ASSOCIATED COLD FRONT APPROACHING AREA ALONG 32N FROM
35W-45W.  SURFACE HIGH PRES 1016 MB CENTERED AT 25N54W BEING
FORCED E BY INCOMING COLD FRONT OVER SW N ATLC.  SHOWERS/
ISOLATED TSTMS ALONG SURFACE TROUGH FROM 31N29W TO 21N45W.
BROAD UPPER LEVEL RIDGE AT 12N33W MAINTAINS ANTICYCLONIC FLOW
ACROSS ENTIRE EAST ATLC WITH FAIRLY ZONAL FLOW E OF 40W.

$$
WALLY BARNES

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