[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130501
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0415 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 37W/38W S OF 9N MOVING W 10 KT IS NOT AS
WELL DEFINED AS 12 HRS AGO. ISOLATED CONVECTION S OF 4N.

...ITCZ...
ITCZ AXIS ALONG 6N11W  3N21W  5N38W  4N51W.  CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION WITHIN 180 NM OF AXIS E OF
19W AND WITHIN 60 NM RADIUS OF 3N24W.  MULTIPLE LAYERS OF CLOUDS
W OF 41W WITH ISOLATED CONVECTION MAINLY S OF 8N.

...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 CROSSING CENTRAL TEXAS
LACKS ENOUGH SUPPORT FOR FRONTOGENESIS AT THIS TIME. UPPER WIND
FLOW BECOMES QUASI-ZONAL OVER GULF OF MEXICO.  THIS SCENARIO
LIKELY TO CHANGE SOON AS GREAT LAKES VORTEX SINKS SLIGHTLY SE
BEFORE TURNING NE MON.  WATER VAPOR IMAGES SHOW CONVECTIVE
DEBRIS FROM LOW PRES CENTER 1006 MB OVER CENTRAL MEXICO AND LOW
PRES 1007 MB OVER E PAC SUPPLYING HIGH LEVEL MOISTURE OVER WRN
GULF OF MEXICO.  GFS MAKES THIS MOISTURE AVAILABLE CONGRUENT
WITH ARRIVAL OF TROUGH IN NW GULF.  EXPECT INCREASE IN CLOUDS
AND PRECIPITATION SUN AS FRONT APPROACHES SE TEXAS COAST.

HIGH PRES 1015 MB OVER CENTRAL GULF SLIDES NE OF BASIN TONIGHT
AND INTO ATLC BY SUN FORCED BY INCOMING FRONT.

CARIBBEAN SEA...
WEAK TRADEWINDS CONTINUE ACROSS ENTIRE BASIN AS ATLC HIGH PRES
1018 MB RETREATS E FORCED BY SW N ATLC COLD FRONT.  IN THE UPPER
LEVELS...CARIBBEAN REMAINS UNDER BROAD RIDGE CENTERED JUST OVER
PANAMA.  SOUTHEASTERN PERIPHERY OF RIDGE HAS PROMPTED SCATTERED
SHOWERS/ISOLATED TSTMS INLAND AND ALONG IMMEDIATE COAST OF SOUTH
AMERICA FROM NE VENEZUELA TO COSTA RICA.  UPPER TROUGH IN THE
CENTRAL ATLC DIPS SW ACROSS TROPICAL ATLC AND EXTREME ERN
CARIBBEAN INCLUDING THE LESSER ANTILLES.  DRY UPPER AIR AND
MODERATE/STRONG SUBSIDENCE COVERS AREA E OF 75W SUPPRESSING ANY
SHOWER ACTIVITY.  SCATTERED CONVECTION OVER YUCATAN
PENINSULA...GUATEMALA...EL SALVADOR AND HONDURAS AS CONVECTIVE
DEBRIS FROM E PAC CROSSES INTO CARIBBEAN BASIN.

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 WEAK CONVECTION
ASSOCIATED MORE TO UPPER LEVEL TROUGH POSITION THAN FRONT AS IT
RUNS WELL AHEAD OF FRONT N OF 26N FROM 60W TO 66W.  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 1018 MB CENTERED AT 25N48W BEING
FORCED E BY INCOMING COLD FRONT OVER SW N ATLC.  SHOWERS/
ISOLATED TSTMS ALONG SURFACE TROUGH FROM 31N33W TO 23N43W.
BROAD UPPER LEVEL RIDGE AT 12N33W MAINTAINS ANTICYCLONIC FLOW
ACROSS ENTIRE EAST ATLC WITH FAIRLY ZONAL FLOW E OF 40W.

$$
WALLY BARNES

This weather bulletin was brought to you by:
www.nashvilleweather.net