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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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