Tropical Weather Discussion
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000
AXNT20 KNHC 280605
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU MAY 28 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 W OF THE ITCZ FROM 1N TO 14N WITH AXIS NEAR
54W...MOVING W AT 15-20 KT DURING THE LAST 24 HOURS. SSMI TPW
IMAGERY SHOW THE WAVE CONTINUES EMBEDDED WITHIN ABUNDANT
MOISTURE IN THE MIDDLE TO LOWER LEVELS. SATELLITE DERIVED WINDS
AND MODEL GUIDANCE SHOW A DIFFLUENT ENVIRONMENT ALOFT E OF THE
WAVE AXIS THAT SUPPORT SCATTERED MODERATE CONVECTION FROM 03N TO
07N BETWEEN THE AXIS AND 50W. FURTHER CONVECTION IS BEING
HINDERED MAINLY BY STRONG DEEP LAYER WIND SHEAR IN THIS REGION
OF THE TROPICAL ATLC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL
ATLANTIC NEAR 09N13W TO 05N21W. THE ITCZ BEGINS NEAR 05N21W AND
CONTINUES ALONG 04N37W TO THE COAST OF NORTHERN BRAZIL NEAR
01N50W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 03N TO
08N E OF 18W. SIMILAR CONVECTION IS WITHIN 60 NM EITHER SIDE OF
THE ITCZ. FOR CONVECTION ASSOCIATED WITH THE TROPICAL WAVE SEE
THE SECTION ABOVE.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE OVER MEXICO EXTENDS E-SE TO THE GULF OF
CAMPECHE WHERE A SURFACE TROUGH IS ANALYZED FROM 22N89W TO
16N93W WITH NO CONVECTION ASSOCIATED WITH IT. BROAD SURFACE HIGH
PRESSURE OVER THE ATLANTIC CONTINUES TO EXTEND A RIDGE AXIS SW
ACROSS THE FLORIDA PENINSULA AND INTO THE REMAINDER GULF. OVER
THE N-NE BASIN...A FORMER SQUALL LINE WEAKENED LEAVING AN
ELONGATED AREA OF LOW PRESSURE FROM NORTHERN ALABAMA TO 30N88W
TO 27N88W. A SHORT-WAVE MIDDLE TO UPPER LEVEL TROUGH GENERATES A
DIFFLUENT ENVIRONMENT ALOFT THAT SUPPORT SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS N OF 26N BETWEEN 85W AND 88W. AN
UPPER LEVEL LOW OVER THE SE GULF SUPPORTS SIMILAR CONVECTION
FROM 24N TO 26N E OF 84W. 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. STRONG DRY AIR
SUBSIDENCE FROM ALOFT HAS DECREASED THE LOW LEVEL MOISTURE BEING
ADVECTED TO THE BASIN...THUS FAVORING STABLE CONDITIONS AND FAIR
WEATHER ELSEWHERE. SURFACE RIDGING WILL CONTINUE TO BE THE
DOMINANT FEATURE DURING THE NEXT THREE DAYS.

CARIBBEAN SEA...

LOW PRESSURE OVER NORTHERN COLOMBIA AND A SLIGHTLY HIGHER
PRESSURE ACROSS THE CARIBBEAN GENERATE A TIGHTER PRESSURE
GRADIENT ALONG THE COAST OF COLOMBIA...RESULTING IN NE TO E
WINDS OF 20 TO 25 KT FROM 11N TO 13N BETWEEN 72W AND 76W WITH
SEAS TO 8 FT. ELSEWHERE...TRADES OF 10 TO 15 KT AND SEAS LESS
THAN 8 FT DOMINATE. SSMI TPW IMAGERY SHOW PATCHES OF MODERATE
LOW LEVEL MOISTURE ALONG THE NORTHERN BASIN SUPPORTING
CLOUDINESS AND POSSIBLE ISOLATED SHOWERS OVER PUERTO RICO AND
HISPANIOLA AND SCATTERED MODERATE CONVECTION AND TSTMS OVER CUBA
SOUTHERN ADJACENT WATERS. FAIR WEATHER IS ELSEWHERE BEING
SUPPORTED BY DEEP LAYER DRY AIR. A TROPICAL WAVE WILL MOVE ACROSS
THE LESSER ANTILLES INTO THE EASTERN BASIN FRIDAY NIGHT.

...HISPANIOLA...

MIDDLE TO UPPER LEVEL TROUGHING ALONG WITH SHALLOW MOISTURE OVER
HISPANIOLA COASTAL WATERS SUPPORT CLOUDINESS AND POSSIBLE
ISOLATED SHOWERS ACROSS THE ISLAND TONIGHT. HOWEVER...UPPER
LEVEL SUBSIDENCE CONTINUE TO SUPPRESS THE FORMATION OF
THUNDERSTORMS. EXPECT...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS THURSDAY AFTERNOON AND EVENING ESPECIALLY OVER THE
NORTH COAST OF HISPANIOLA.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 25N62W CONTINUE TO
SUPPORT A SURFACE TROUGH WITH AXIS EXTENDING FROM 30N62W TO
25N66W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE N
OF 25N BETWEEN 50W AND 64W. A TROPICAL WAVE IS W OF THE ITCZ.
SEE THE TROPICAL WAVES SECTION ABOVE. ELSEWHERE SURFACE HIGH
PRESSURE AND FAIR WEATHER PREVAILS. THE SURFACE TROUGH WILL
PREVAIL OVER THE SW N ATLC DURING THE NEXT THREE DAYS. SURFACE
RIDGING WILL DOMINATE ELSEWHERE. THE TROPICAL WAVE WILL ENTER
THE EASTERN CARIBBEAN FRIDAY NIGHT.

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

$$
NR



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