[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAY 28 2011

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
0535 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS OFF THE COAST OF SURINAME FROM 11N54W TO 6N55W
MOVING W AT 10-15 KT. CYCLONIC FLOW IS NOTED ALONG THE NORTHER
AXIS IN THE LOW-LEVEL CLOUD PATTERN. HOWEVER...DRY NW FLOW IN
THE MIDDLE TO UPPER LEVELS ABOVE THE LOW-LEVEL WAVE SIGNATURE IS
INHIBITING ANY SIGNIFICANT CONVECTION WITH THE WAVE THIS EVENING.

TROPICAL WAVE IS INLAND OVER VENEZUELA FROM 10N63W TO 5N64W
MOVING W AT ABOUT 10 KT. THIS WAVE IS EXPECTED TO REMAIN INLAND
AND CONTINUE TO MOVE WEST WITH CONVECTION OVER THE NEXT 24 HOURS.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF SIERRA LEONE NEAR
9N13W SW ALONG 6N20W 4N30W 3N40W EQ50W. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS WITHIN 120 NM ON EITHER SIDE OF
THE AXIS E OF 44W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY COMBINED WITH UPPER LEVEL SATELLITE DERIVED
WINDS INDICATE NW FLOW ALOFT MOVING A VERY DRY AIRMASS ACROSS
THE GULF. AT SURFACE...WEAK SURFACE RIDGING COVERS THE AREA...
CENTERED OVER THE NE CORNER OF THE BASIN BY A 1014 MB HIGH NEAR
27N85W. THE OUTPUT OF THESE CONDITIONS BRING FAIR WEATHER ACROSS
THE DISCUSSION AREA THIS EVENING. HOWEVER...HAZY SKIES ACROSS
THE WESTERN HALF OF THE BASIN IS POSSIBLE DUE TO THE ADVECTION
OF SMOKE FROM THE SOUTHERN MEXICO WILDFIRES. OTHERWISE...NO
SIGNIFICANT CHANGES ARE EXPECTED OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...
DRY WESTERLY ZONAL FLOW ALOFT IS NOTED ACROSS MUCH OF THE
CARIBBEAN SEA THIS EVENING. THIS FEATURE IS KEEPING FAIR WEATHER
CONDITIONS OVER MUCH OF THE CARIBBEAN...WITH A FEW ISOLATED
SHOWERS LINGERING WITHIN 20 NM WEST AND SW OF THE GREATER
ANTILLES. ON THE OTHER HAND...BROAD CYCLONIC TURNING IS NOTED ON
THE S CENTRAL BASIN ACROSS THE COASTAL WATERS OF COLOMBIA. LOW
LEVEL MOISTURE REMAINS QUITE HIGH IN THIS REGION...NOTICED ON
TPW PRODUCT. SCATTERED SHOWERS AND TSTMS ARE S OF 12N AND W OF
74W. THIS CONVECTION REMAINS ENHANCED OVER INTERIOR PORTIONS OF
PANAMA AND COSTA RICA DUE TO THE CLOSE PROXIMITY OF THE EASTERN
PACIFIC OCEAN ITCZ AXIS. MODEL GUIDANCE SUGGEST THE ACTIVITY IN
THE SW BASIN WILL INCREASE OVER THE NEXT 24 HOURS...AS A WEAK
LOW/TROUGH SYSTEM DEVELOPS IN THIS REGION.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE WESTERN ATLC W OF 63W KEEPING
CONDITIONS MOSTLY FAIR THIS EVENING. FARTHER EAST...A BROAD
ELONGATED UPPER LEVEL LOW/TROUGH CONTINUES TO ROTATE AROUND
31N52W. THIS UPPER LEVEL FEATURE IS SUPPORTING A SERIES OF
SURFACE LOWS MOVING ACROSS THE S CENTRAL ATLC...ANALYZED AS A
1015 MB LOW NEAR 27N54W...A 1014 MB LOW NEAR 30N57W...AND A 1014
MB LOW NEAR 23N53W. A SURFACE TROUGH EXTENDS FROM THE
EASTERNMOST LOW TO 19N57W. DESPITE THE LOCATION OF THESE SURFACE
LOWS...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS N OF
18N BETWEEN 44W-51W...ASSOCIATED TO DIFFLUENCE FLOW ALOFT NOTED
ON UPPER LEVEL SATELLITE DERIVED WINDS. WITHIN THIS AREA OF
CONVECTION...A SHEAR LINE AXIS EXTENDS ALONG 32N47W TO 27N45W.
THE PRESSURE GRADIENT IN THIS REGION REMAINS QUITE STRONG. AN
EARLIER ASCAT PASS DEPICTED A CONTRAST OF 5 KT TO 25 KT FROM THE
SW TO THE NE SIDE OF THE SHEAR AXIS. THE REMAINDER OF THE
EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE KEEPING
FAIR WEATHER CONDITIONS E OF 40W. FINALLY...AN ELONGATED UPPER
LEVEL LOW IS CENTERED NE OF THE MADEIRA ISLANDS. SUPPORTS A
SURFACE TROUGH EXTENDING FROM 33N13W TO 27N20W.

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

$$

GARCIA



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