Tropical Weather Discussion
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000
AXNT20 KNHC 290606 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI MAY 29 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS E OF THE LESSER ANTILLES S OF 19N WITH AXIS
NEAR 59W...MOVING W AT 15 KT DURING THE LAST 24 HOURS. SSMI TPW
IMAGERY SHOW MODERATE MOISTURE BEHIND THE WAVE AXIS AND ABUNDANT
MOISTURE AHEAD OF IT IN THE SE CARIBBEAN. A SLIGHT MIDDLE-LEVEL
DIFFLUENT ENVIRONMENT SUPPORT SCATTERED MODERATE CONVECTION N OF
THE WAVE AXIS FROM 15N TO 18N BETWEEN 41W AND 63W. SIMILAR
CONVECTION IS WITHIN 200 NM EITHER SIDE OF THE WAVE AXIS S OF
11N. FURTHER CONVECTION IS BEING HINDERED IN PART BY STRONG DEEP
LAYER WIND SHEAR IN THIS REGION OF THE TROPICAL ATLC AND EASTERN
CARIBBEAN.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL
ATLANTIC NEAR 11N16W TO 06N21W. THE ITCZ BEGINS NEAR 06N21W AND
CONTINUES ALONG 04N32W TO 03N41W TO THE COAST OF NORTHERN BRAZIL
NEAR 03N51W. A CLUSTER OF MODERATE CONVECTION ASSOCIATED WITH A
TROPICAL WAVE OVER THE E ATLC IS FROM 01N TO 07N BETWEEN 21W AND
29W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM
03N TO 10N E OF 20W. SCATTERED MODERATE CONVECTION IS WITHIN 75
NM EITHER SIDE OF THE ITCZ W OF 32W. FOR CONVECTION ASSOCIATED
WITH THE TROPICAL WAVE E OF THE LESSER ANTILLES SEE THE SECTION
ABOVE.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE PREVAILS ACROSS MEXICO...INCLUDING THE
YUCATAN PENINSULA WHERE A SURFACE TROUGH IS ANALYZED ALONG
21N88W TO 14N92W WITH NO CONVECTION ASSOCIATED WITH IT. BROAD
SURFACE HIGH PRESSURE OVER THE ATLANTIC ANCHORED BY A 1032 MB
CENTER NEAR 38N48W CONTINUES TO EXTEND A RIDGE AXIS SW ACROSS
THE FLORIDA PENINSULA AND INTO THE REMAINDER GULF. OVER THE FAR
EASTERN GULF...A WEAKNESS IN THE RIDGE IS ANALYZED AS A SURFACE
TROUGH WITH AXIS FROM 31N83W TO 25N82W BEING SUPPORTED BY AN
UPPER LEVEL LOW. STRONG DRY AIR SUBSIDENCE FROM ALOFT HAS
DECREASED THE LOW LEVEL MOISTURE BEING ADVECTED TO THE BASIN
FROM THE ATLC AND THE CARIBBEAN...THUS FAVORING STABLE
CONDITIONS AND FAIR WEATHER ACROSS THE GULF. EASTERLY TO
SOUTHEASTERLY WIND FLOW OF 10 TO 15 KT ASSOCIATED WITH THE RIDGE
DOMINATES THE GULF...EXCEPT OVER THE STRAITS OF FLORIDA...THE
YUCATAN CHANNEL AND ALONG THE WESTERN YUCATAN PENINSULA WHERE
WINDS INCREASE TO 20 KT DUE TO A TIGHTER PRESSURE GRADIENT.
SURFACE RIDGING WILL CONTINUE TO BE THE DOMINANT FEATURE DURING
THE NEXT THREE DAYS.

CARIBBEAN SEA...

ABUNDANT MOISTURE IS OVER THE SW CARIBBEAN DUE TO ADVECTION FROM
NORTHERN SOUTHERN AMERICA AND THE E PAC WATERS. THE SE BASIN IS
BEING MOISTEN BY UPPER LEVEL SOUTHERLY FLOW FROM NORTHERN SOUTH
AMERICA AND BY A TROPICAL WAVE WITH AXIS E OF THE LESSER ANTILLES.
THE MOISTURE ENHANCES SCATTERED MODERATE TO ISOLATED SHOWERS
ACROSS THE EASTERN CARIBBEAN S OF 18N AND OVER THE SW BASIN S OF
15N. AN UPPER TROUGH IS OVER THE N-NW BASIN THAT ALONG WITH
PATCHES OF MODERATE LOW LEVEL MOISTURE SUPPORT CLOUDINESS AND
ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA...CUBA AND ADJACENT
WATERS. MOISTURE AND SHOWER ACTIVITY OVER THE EASTERN AND
CENTRAL BASIN WILL CONTINUE TO INCREASE AS THE TROPICAL WAVE
MOVES ACROSS THE LESSER ANTILLES FRIDAY. FAIR WEATHER IS
ELSEWHERE BEING SUPPORTED BY DRY AIR SUBSIDENCE FROM ALOFT.

...HISPANIOLA...

MIDDLE TO UPPER LEVEL TROUGHING ASSOCIATED WITH A LOW ALOFT OVER
THE SW N ATLC ALONG WITH SHALLOW MOISTURE SUPPORT CLOUDINESS AND
ISOLATED SHOWERS AND TSTMS ACROSS THE ISLAND AND ADJACENT
WATERS. THIS CONVECTION IS FORECAST THROUGH FRIDAY
MORNING...RESUMING AGAIN FRIDAY NIGHT ASSOCIATED WITH MOISTURE
FROM A TROPICAL WAVE ENTERING THE E CARIBBEAN DURING THE MORNING
HOURS.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 28N60W CONTINUE TO
SUPPORT A 1016 MB LOW NEAR 27N60W WITH SCATTERED TO ISOLATED
MODERATE CONVECTION N OF 24N BETWEEN 51W AND 62W. THIS LOW IS
FORECAST TO DISSIPATE BY FRIDAY EVENING LEAVING A SURFACE TROUGH
TO DRIFT W OVER THE SW N ATLC THE NEXT THREE DAYS. NE OF THE
SOUTHERN BAHAMAS...A 1015 MB LOW IS ANALYZED WITH A SURFACE
TROUGH FROM 29N66W TO THE LOW CENTER NEAR 25N67W. NO CONVECTION
IS ASSOCIATED WITH THIS SECOND LOW THAT IS FORECAST TO DISSIPATE
FRIDAY AFTERNOON. A TROPICAL WAVE IS E OF THE LESSER ANTILLES.
SEE THE TROPICAL WAVES SECTION ABOVE. ELSEWHERE SURFACE HIGH
PRESSURE AND FAIR WEATHER PREVAILS. THE TROPICAL WAVE WILL ENTER
THE EASTERN CARIBBEAN BASIN FRIDAY.

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

$$
NR



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