Tropical Weather Discussion
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000
AXNT20 KNHC 291046
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE EASTERN ATLC W OF THE MONSOON TROUGH
WITH AXIS NEAR 24W. A SATELLITE HOVEMOLLER DIAGRAM INDICATE THE
WAVE CAME OFF THE AFRICAN COAST EARLY THURSDAY MORNING. SSMI TPW
IMAGERY SHOW ABUNDANT MIDDLE TO LOWER LEVEL MOISTURE WITHIN 200
NM AHEAD OF THE WAVE AXIS WHERE IT ENHANCES SCATTERED MODERATE
CONVECTION. ENHANCEMENTS OF METEOSAT SATELLITE IMAGERY SHOW DRY
AIR AND DUST BEHIND THE WAVE AXIS WHERE A LACK OF CONVECTION IS
NOTICED.

A TROPICAL WAVE IS E OF THE LESSER ANTILLES S OF 19N WITH AXIS
NEAR 60W...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 FROM
16N TO 20N BETWEEN 54W AND 61W. SIMILAR CONVECTION IS FROM 08N
TO 11N BETWEEN 57W AND 62W. 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 11N15W TO 06N22W. THE ITCZ BEGINS W OF A TROPICAL
WAVE NEAR 04N25W AND CONTINUES ALONG 03N40W TO THE NORTHERN
COAST OF SOUTH AMERICA NEAR 04N52W. SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS ARE FROM 02N TO 09N E OF 15W. A
CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS FROM 02N TO
05N W OF 48W. FOR CONVECTION ASSOCIATED WITH THE TROPICAL WAVES
SEE THE SECTION ABOVE.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE PREVAILS ACROSS MEXICO AND EXTENDS SE TO
THE BAY OF CAMPECHE WHERE A SURFACE TROUGH IS ANALYZED ALONG
22N90W TO 15N93W WITH NO CONVECTION ASSOCIATED WITH IT. BROAD
SURFACE HIGH PRESSURE OVER THE ATLANTIC ANCHORED BY TWO 1030 MB
CENTERS 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 31N85W TO 25N84W 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 INCLUDING PUERTO RICO 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 TODAY. 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 LATER THIS
MORNING...RESUMING AGAIN TONIGHT AS MOISTURE IN THE ENVIRONMENT
INCREASE ASSOCIATED WITH A TROPICAL WAVE ENTERING THE E
CARIBBEAN LATER TODAY.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 28N60W CONTINUE TO
ENHANCE SCATTERED TO ISOLATED MODERATE CONVECTION AND TSTMS N OF
26N BETWEEN 51W AND 62W. NORTHEAST OF THE SOUTHERN BAHAMAS A
1015 MB LOW IS ANALYZED NEAR 25N68W WITH SURFACE TROUGH FROM
27N66W TO 23N70W. ISOLATED SHOWERS ARE WITHIN 200 NM OF THE LOW
CENTER...ESPECIALLY IN THE NE QUADRANT. THE LOW WILL DISSIPATE
LATER TODAY AND THE TROUGH WILL CONTINUE TO DRIFT W OVER THE SW
N ATLC THE NEXT THREE DAYS. TWO TROPICAL WAVES ARE IN THE
ATLC...ONE E OF THE LESSER ANTILLES AND ANOTHER OVER THE EASTERN
BASIN W OF THE MONSOON TROUGH. SEE THE TROPICAL WAVES SECTION
ABOVE. ELSEWHERE SURFACE HIGH PRESSURE AND FAIR WEATHER
PREVAILS. THE TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN
LATER TODAY.

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

$$
NR


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