[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON JUL 04 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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
2330 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 19N37W
TO 9N41W MOVING W 15-20 KT. WAVE IS WELL DEFINED IN THE LOW
LEVEL WINDS AND AS A BROAD INVERTED V STRUCTURE ON SATELLITE
IMAGERY. WAVE IS PRECEDING A DEEP MOISTURE SURGE INDICATED ON
THE TOTAL PRECIPITABLE WATER IMAGERY. THE MOISTURE IS WRAPPING
AROUND THE TOP END OF THE WAVE FORMING A DRY SLOT ALONG THE
CENTRAL PORTION OF THE WAVE. SCATTERED MODERATE CONVECTION IS
WITHIN 50 NM ON EITHER SIDE OF THE AXIS S OF 15N.

TROPICAL WAVE IS MOVING ACROSS THE NW CARIBBEAN ANALYZED FROM
21N81W TO 13N81W MOVING WNW AT ABOUT 10-15 KT. WAVE REMAINS
EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE THAT
COVERS MOST OF THE N CENTRAL AND NW CARIBBEAN BASIN. THE WAVE
LIES UNDERNEATH AN AREA OF DIFFLUENCE ALOFT WHICH IS HELPING
SUPPORT CONVECTION NEAR THE WAVE. SCATTERED MODERATE TO STRONG
CONVECTION IS WITHIN 150/200 NM EITHER SIDE OF THE WAVE AXIS.
HOWEVER...SIMILAR CONVECTION COVERS A GREAT PORTION OF THE
CARIBBEAN DUE TO THE UPPER LEVEL ENVIRONMENT.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INLAND OVER AFRICA AND ENTERS THE
EAST TROPICAL ATLC THROUGH GUINEA FROM 10N14W TO 6N21W. THE
ITCZ AXIS STARTS FROM 6N21W CONTINUING W ALONG 5N30W 8N40W 9N50W
7N58W. SCATTERED WEAK TO MODERATE CONVECTION IS WITHIN 100/130
NM ON EITHER SIDE OF THE ITCZ W OF 37W. SCATTERED STRONG
CONVECTION IS WITHIN 120 NM N OF THE MONSOON TROUGH E OF 21W TO
THE COAST OF GUINEA.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL CYCLONIC FLOW COVERS THE DISCUSSION AREA THIS
EVENING CENTERED NEAR 24N88W. THIS FEATURE SUPPORTS A SURFACE
TROUGH AXIS ANALYZED FORM 27N91W TO 24N91W. SCATTERED WEAK
SHOWERS ARE WITHIN 50/80 NM ON EITHER SIDE OF THE AXIS. MOIST
DIFLUENT FLOW ALOFT OVER THE SE BASIN IS GENERATING SCATTERED
HEAVY SHOWERS AND ISOLATED THUNDERSTORMS S OF 27N E OF 87W. THIS
ACTIVITY IS EXPECTED TO PERSIST OVER THE NEXT FEW DAYS AS THE
UPPER LOW REMAINS OVER THE CENTRAL GULF. THE REMAINDER OF THE
BASIN IS UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS. EXPECT THE
SURFACE TROUGH TO CONTINUE TO DRIFT W WITH LIMITED CONVECTION IN
ITS VICINITY.

CARIBBEAN SEA...
SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE OVER THE N CENTRAL
AND NW CARIBBEAN...INCLUDING INLAND PORTIONS OVER THE GREATER
ANTILLES AND CENTRAL AMERICA N OF 14N W OF 68W...DUE TO A
TROPICAL WAVE MOVING ACROSS THE NW BASIN...AND A BROAD AREA OF
DEEP LAYER MOISTURE ACROSS MUCH OF THE AREA ENHANCED BY SWLY
FLOW ALOFT OVER THE WRN BASIN. FOR MORE DETAILS ABOUT THE WAVE
SEE DISCUSSION ABOVE. MUCH OF THE ERN CARIBBEAN E OF 68W IS
EXPERIENCING GENERALLY FAIR WEATHER INFLUENCED BY SOME DRY AIR
ALOFT. WEATHER CONDITIONS ARE EXPECTED TO REMAIN CONSTANT IN THE
WESTERN CARIBBEAN AS THE TROPICAL WAVE CONTINUES TO MOVE ACROSS
THE WNW BASIN OVER THE NEXT 24-36 HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE COVERS THE FAR WRN ATLC ANCHORED BY A 1019
MB HIGH NEAR 30N75W KEEPING THIS PORTION OF THE BASIN UNDER FAIR
CONDITIONS. HOWEVER...A SURFACE TROUGH IS MOVING ACROSS THE
BAHAMAS...ANALYZED FROM 25N72W TO 20N76W. CLUSTERS OF SCATTERED
HEAVY SHOWERS AND THUNDERSTORMS ARE S OF 26N BETWEEN 68W-78W. AN
UPPER LEVEL LOW IS TO THE NE OF THE CONVECTION AREA NEAR 29N68W.
THIS FEATURE IS ENHANCING THE CONVECTION ASSOCIATED TO THE
SURFACE TROUGH AND AT THE SAME TIME EXPANDING IT TO THE NE. THE
SURFACE TROUGH IS EXPECTED TO CONTINUE TO TRACK NW ACROSS THE
BAHAMAS WITH CONVECTION OVER THE NEXT 24-48 HOURS. THE REMAINDER
OF THE ATLC IS DOMINATED BY A BROAD RIDGE ANCHORED BY A 1028 MB
HIGH NEAR 38N43W. THIS BROAD SYSTEM IS PROVIDING MOSTLY FAIR
WEATHER ACROSS THE CENTRAL AND ERN ATLC. ANOTHER UPPER LOW IS
EMBEDDED IN THE BROAD RIDGE SPINNING NEAR 23N50W WITH NO
ASSOCIATED CONVECTION.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA




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