[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 281803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED MAY 28 2014

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS OVER THE EASTERN TROPICAL ATLC WITH AXIS ALONG
28W...JUST IN THE WESTERN PERIPHERY OF A SAHARAN DUST OUTBREAK
NOTED ON METEOSAT PSEUDO NATURAL COLOR IMAGERY. THE SOUTHERN
PORTION OF THE WAVE IS EMBEDDED WITHIN THE ITCZ AXIS MOIST
ENVIRONMENT WHERE SCATTERED MODERATE CONVECTION IS OBSERVED FROM
1N-4N BETWEEN 25W-33W. THE REMAINDER WAVE ENVIRONMENT IS DEVOID
OF CONVECTION DUE TO THE PRESENCE OF DEEP LAYER DRY AIR.

A SECOND TROPICAL WAVE IS EMBEDDED WITHIN THE ITCZ WITH AXIS
NEAR 40W/41W...MOVING W ABOUT 15 KT DURING THE LAST 24 HOURS.
EVEN THAT THE WAVE SIGNAL IN MODEL GUIDANCE IS VERY SUBTLE AT
700 HPA...AN INVERTED-V CLOUD PATTERN ASSOCIATED WITH THIS WAVE
IS DISCERNIBLE ON SATELLITE IMAGERY. SCATTERED MODERATE
CONVECTION IS FROM 1N-5N W OF 39W.

A TROPICAL WAVE IS MOVING ACROSS THE SOUTHERN CARIBBEAN BASIN
WITH AXIS EXTENDING FROM 13N66W TO INLAND VENEZUELA NEAR 6N68W.
THE WAVE LIES JUST IN A CONFLUENCE ZONE IN THE MIDDLE TO UPPER
LEVELS AND HAS BEEN MOVING W NEAR 20 KT DURING THE LAST 24
HOURS. STRONG SW DEEP LAYER WIND SHEAR OVER THE EASTERN
CARIBBEAN IS LIMITING THE CONVECTION TO SCATTERED/ISOLATED
SHOWERS WITHIN 200 NM OF THE WAVE AXIS.

A TROPICAL WAVE IS OVER THE SW CARIBBEAN BASIN WITH AXIS ALONG
76W. THE WAVE HAS BEEN MOVING NEAR 15 KT DURING THE LAST 24
HOURS. ISOLATED SHOWERS ARE S OF 10N WITHIN 20 NM EITHER SIDE OF
THE WAVE AXIS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
6N10W TO 3N17W WHERE THE ITCZ AXIS CONTINUES ALONG 3N25W. THE
ITCZ RESUMES W OF A TROPICAL WAVE FROM 2N30W TO 3N39W...THEN AGAIN
W OF A SECOND TROPICAL WAVE FROM 2N42W TO 1N49W. SCATTERED MODERATE
CONVECTION IS FROM 0N-5N E OF 16W...FROM 1N-4N BETWEEN 24W-
32W AND FROM 1N-5N W OF 39W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL LOW ON THE BORDER BETWEEN THE SOUTHERN
PLAINS AND THE LOWER MISSISSIPPI IS SUPPORTING A 1011 MB LOW
OVER SOUTHERN LOUISIANA AND A SQUALL LINE EXTENDING FROM
SOUTHERN MISSISSIPPI SW TO 29N92W TO 28N96W. HEAVY SHOWERS AND
TSTMS ARE OVER THE NW GULF N OF 27N W OF 91W. THIS CONVECTION IS
BEING FUELED BY MOISTURE BEING ADVECTED FROM THE CARIBBEAN AND
WESTERN ATLC BY SE WIND FLOW. THE MIDDLE LEVEL LOW EXTENDS A
TROUGH TO THE WESTERN GULF TO SUPPORT A SURFACE TROUGH OVER THE
BAY OF CAMPECHE ALONG 22N94W TO 17N93W...HOWEVER THERE IS NO
CONVECTION ASSOCIATED WITH IT. THE AZORES HIGH EXTENDS A RIDGE
AXIS SW TO COVER THE EASTERN GULF...THUS SUPPORTING RETURN FLOW
OF 10-15 KT ACROSS THE BASIN. OTHERWISE...DIFFLUENCE ALOFT NEAR
THE STRAITS REGION IS SUPPORTING SCATTERED/ISOLATED HEAVY
SHOWERS AND TSTMS ACROSS PORTIONS OF SOUTHERN FLORIDA AND
ADJACENT WATERS. RAINSHOWERS ARE EXPECTED TO CONTINUE TO AFFECT
THE NORTHER GULF WITHIN THE NEXT DAY OR TWO.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL RIDGING COVERS THE FAR WESTERN AND EASTERN
CARIBBEAN WHILE A SHORT WAVE TROUGH DOMINATES ACROSS THE CENTRAL
BASIN. TWO TROPICAL WAVES ARE MOVING ACROSS THE SOUTHERN
CARIBBEAN WATERS...SEE THE WAVES SECTION ABOVE. DEEP LAYER
MOISTURE ACROSS CUBA ALONG WITH DIFFLUENCE ALOFT IS SUPPORTING
SCATTERED/ISOLATED HEAVY SHOWERS AND TSTMS OVER CUBA AND
ADJACENT WATERS. LIGHTING DATA INDICATE ISOLATED TSTMS OVER
HISPANIOLA AS WELL. A MIDDLE TO UPPER LEVEL CONFLUENCE ZONE IS
OVER THE EASTERN CARIBBEAN WHERE DEEP LAYER MOISTURE IS
NOTED...THIS IS SUPPORTING A SWATH OF SCATTERED/ISOLATED
MODERATE CONVECTION E OF A LINE FROM 18N67W TO 11N74W. A NEW
TROPICAL WAVE IS EXPECTED TO ENTER THE EASTERN CARIBBEAN FRIDAY
NIGHT SUPPORTING MORE SHOWERS FOR THIS REGION.

...HISPANIOLA...
A SHORT WAVE MIDDLE TO UPPER LEVEL TROUGH IS OVER THE CENTRAL
CARIBBEAN WITH ASSOCIATED MOISTURE REMAINING MINIMAL ACROSS THE
ISLAND TO SUPPORT ONLY ISOLATED SHOWERS AND TSTMS.
OTHERWISE...LITTLE CHANGE IS EXPECTED THROUGH WED. DEEP MOISTURE
OVER THE EASTERN CARIBBEAN AHEAD OF THE TROUGH...AND ALSO
ASSOCIATED WITH THE TROPICAL WAVE IN THAT AREA AS DESCRIBED
ABOVE MAY APPROACH THE SE PART OF THE ISLAND LATE WED.

ATLANTIC OCEAN...
A NARROW UPPER LEVEL RIDGE OVER THE FAR SW N ATLC IS JUST N OF
THE SHORT WAVE TROUGH COVERING THE CENTRAL CARIBBEAN THUS
GENERATING DIFFLUENT FLOW ALOFT TO SUPPORT SCATTERED/ISOLATED
HEAVY SHOWERS AND TSTMS OVER THE STRAITS OF FLORIDA AND THE
GREAT BAHAMAS BANK. FARTHER EAST...A CONFLUENCE ZONE BETWEEN A
NARROW TROUGH ALOFT BETWEEN 60W-70W AND A BROAD RIDGE COVERING
THE CENTRAL ATLC SUPPORTS SCATTERED MODERATE CONVECTION S OF 30N
BETWEEN 40W-66W. OTHERWISE...BESIDES THE TROPICAL WAVES ALREADY
DISCUSSED...THE AZORES HIGH EXTENDS A RIDGE ACROSS THE BASIN N
OF 11N THUS SUPPORTING FAIR WEATHER ELSEWHERE.

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

$$
NR


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