[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091155
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 09 2015

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLC WITH AXIS NEAR 22W...MOVING W
AT 5-10 KT. ACCORDING TO METEOSAT IMAGERY...THE WAVE CONTINUES
BEING ENGULFED BY SAHARAN DRY AIR AND DUST...WHICH IS SUPPORTING
LACK OF CONVECTION N OF 13N AHEAD AND NE OF ITS AXIS. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION AND TSTMS ARE FROM 10N TO
15N E OF 21W WHERE SSMI TPW IMAGERY DEPICT ABUNDANT MOISTURE.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN BASIN WITH AXIS
APPROXIMATELY ALONG 78W...MOVING W AT 10 KT. SSMI TOTAL
PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS ASSOCIATED WITH
A LOW TO MODERATE MOIST ENVIRONMENT N OF 13N AND ABUNDANT
MOISTURE S OF 13N. A DIVERGENT ENVIRONMENT ALOFT IN THE EPAC
MONSOON TROUGH REGION AND ALONG CENTRAL AMERICA SUPPORT ISOLATED
MODERATE CONVECTION AND TSTMS S OF 14N AHEAD OF THE WAVE AXIS.
STRONG DEEP LAYER WIND SHEAR ACROSS THE CENTRAL-NORTHERN
CARIBBEAN HINDER CONVECTION DEVELOPMENT ELSEWHERE IN THE
VICINITY OF THE WAVE.

A TROPICAL WAVE MOVES ACROSS CENTRAL AMERICA WITH AXIS
APPROXIMATELY NEAR 88W...MOVING W AT 15 KT. SSMI TOTAL
PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS ASSOCIATED WITH
A MODERATE MOIST ENVIRONMENT N OF 13N THAT ALONG WITH A
DIFFLUENT ENVIRONMENT ALOFT SUPPORT SCATTERED MODERATE
CONVECTION AND TSTMS S OF 20N W OF 84W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
08N24W TO 08N42W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 08N42W TO 06N57W. ASIDE FROM THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE ALONG 22W...SCATTERED MODERATE
CONVECTION IS FROM 05N TO 10N BETWEEN 20W AND 29W AND FROM 06N
TO 10N BETWEEN 35W AND 41W.

...DISCUSSION...

GULF OF MEXICO...

THE WESTERN GULF BASIN IS UNDER THE INFLUENCE OF AN ELONGATED
UPPER LOW CENTERED NEAR OAXACA MEXICO WHILE E OF 90W THE
SOUTHERN PERIPHERY OF AN UPPER-LEVEL ANTICYCLONE CENTERED OVER
SW VIRGINIA COVER THE NE BASIN. S OF 26N...AN ELONGATED UPPER
RIDGE COVERS THE SE GULF EXTENDING S-SE INTO THE WESTERN AND
PORTIONS OF THE CENTRAL CARIBBEAN. SSMI TOTAL PRECIPITABLE WATER
IMAGERY SHOW MOISTURE INFLOW FROM THE NW CARIBBEAN INTO THE BAY
OF CAMPECHE THAT ALONG WITH A DIFFLUENT ENVIRONMENT ALOFT
SUPPORT ISOLATED MODERATE CONVECTION S OF 24N E OF 95W WHERE A
SURFACE TROUGH IS ANALYZED FROM 23N92W TO 18N93W. A SIMILAR
ATMOSPHERIC ENVIRONMENT IN THE SE GULF SUPPORTS ISOLATED SHOWERS
AND TSTMS FROM 24N TO 28N E OF 85W. OTHERWISE...SURFACE HIGH
PRESSURE AND RIDGING HOLD ANCHORED BY A 1021 MB CENTER NEAR
29N87W. N TO NE WINDS OF 20 TO 25 KT ARE FROM 20N TO 22N BETWEEN
89W AND 92W WITH SEAS LESS THAN 8 FT. E TO SE WINDS OF 15 KT
DOMINATE ELSEWHERE EXCEPT NEARBY THE HIGH CENTER IN THE NE GULF
WHERE WINDS ARE OF 5 KT. MODERATE TO OCCASIONAL FRESH E TO SE
WINDS ARE FORECAST TO PERSIST THROUGH THE WEEK AS THE HIGH
REMAINS NEARLY STATIONARY ACROSS THE NE GULF WATERS.

CARIBBEAN SEA...

LOW TO MODERATE MOISTURE IS ACROSS THE CENTRAL AND NW BASIN WITH
ABUNDANT MOISTURE PREVAILING IN THE SW CARIBBEAN. THIS MOISTURE
IS ASSOCIATED WITH TWO TROPICAL WAVES...ONE WITH AXIS NEAR 78W
AND ANOTHER MOVING ACROSS CENTRAL AMERICA. A DIVERGENT
ENVIRONMENT ALOFT ALONG CENTRAL AMERICA AND OVER THE SW BASIN
SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS IN THE VICINITY
OF THE WAVES. SEE THE TROPICAL WAVES SECTION FOR FURTHER
DETAILS. SSMI TOTAL PRECIPITABLE WATER IMAGERY SHOW MAINLY DRY
AIR ACROSS THE REMAINDER BASIN...INCLUDING THE LESSER
ANTILLES...PUERTO RICO...HISPANIOLA AND CUBA WHERE DUST AND HAZY
CONDITIONS ARE BEING REPORTED. NE TO E WINDS OF 20 TO 25 KT ARE
FROM 10.5N TO 16N BETWEEN 73W AND 79W...EXCEPT S OF 13N BETWEEN
74W AND 76W WHERE WINDS INCREASE TO 30 KT. SEAS IN THIS REGION
ARE FROM 8 TO 11 FT. ELSEWHERE FROM 11N TO 17N BETWEEN 76W AND
82W WINDS ARE 20 KT OR LESS WITH SEAS FROM 8 TO 10 FT IN NE TO E
SWELL. E TO SE WINDS 20 TO 25 KT ARE FROM 17N TO 18N BETWEEN 71W
AND 73W WITH SEAS LESS THAN 8 FT.

...HISPANIOLA...

SHALLOW MOIST AIR ASSOCIATED WITH THE PASSAGE OF A TROPICAL
WAVES ACROSS THE CENTRAL CARIBBEAN ALONG WITH AIR LIFTING
PROVIDED BY AN UPPER LEVEL LOW JUST N OF THE ISLAND SUPPORT
CLOUDINESS AND POSSIBLE ISOLATED SHOWERS THIS MORNING. SSMI TPW
AND METEOSAT SAL TRACKING IMAGERY SHOW SAHARAN DRY AIR AND DUST
STARTING TO MOVE ACROSS THE ISLAND THAT MODEL GUIDANCE FORECAST
THROUGH THURSDAY NIGHT...WHICH WILL FAVOR FAIR WEATHER BUT HAZY
CONDITIONS.

ATLANTIC OCEAN...

AN UPPER LEVEL LOW OVER THE SW N ATLC CENTERED NEAR 23N72W ALONG
WITH SHALLOW MOISTURE SUPPORT ISOLATED SHOWERS AND TSTMS FROM
23N TO 27N BETWEEN 72W AND 78W. AN UPPER TROUGH EXTENDS FROM THE
NORTHERN CENTRAL ATLC SW TO A LOW CENTERED NEAR 24N54W. THE
TROUGH ALOFT SUPPORT A STATIONARY FRONT THAT EXTENDS FROM 30N46W
TO 28N50W TO A 1019 MB LOW NEAR 31N56W FROM WHICH A SURFACE
TROUGH EXTENDS SW TO 28N63W. ISOLATED SHOWERS AND TSTMS ARE FROM
27N TO 30N BETWEEN 53W AND 63W. AHEAD OF THE STATIONARY
FRONT...A SURFACE TROUGH DEVOID OF CONVECTION EXTENDS FROM
31N41W TO 27N45W. THE REMAINDER OF THE ATLC N OF 18N IS UNDER
THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1022 MB HIGH
CENTERED NEAR 31N69W AND A 1021 MB HIGH NEAR 32N35W. HIGH
PRESSURE AND RIDGING WILL BE THE DOMINANT FEATURE THE NEXT THREE
DAYS. FOR TROPICAL WAVES INFORMATION...SEE SECTION ABOVE.

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

$$
NR
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