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AXNT20 KNHC 230005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON SEP 22 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC.


...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 22N24W TO A 1010 MB LOW NEAR 17N25W TO 11N26W MOVING W AT 10-15 KT. THE GOES-R SEVIRI AIRMASS PRODUCT DEPICT A SLOT OF WARM DRY AIR W OF THE LOW CENTER WHICH THE SSMI TPW AND THE METEOSAT SAL IMAGERY SHOW ENTRAINING THE SYSTEM. SAHARAN DUST IS ALSO ENTRAINING THE WAVE ENVIRONMENT AS DEPICTED IN THE GOES-R DUST PRODUCT. AS A RESULT CONVECTION HAS DECREASED TO ISOLATED SHOWERS WITHIN 300 NM OF THE LOW CENTER...EXCEPT IN THE NW QUADRANT.

A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM 17N41W TO 9N44W...MOVING W AT 20 KT. THE WAVE REMAINS WEAKER DUE THE PRESENCE OF DRY AND STABLE SAHARAN AIR KEEPING CONVECTION TO A MINIMUM AND LARGELY CONFINED TO THE MONSOON TROUGH REGION S OF 12N BETWEEN 40W-50W.

A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 21N63W TO 10N64W...MOVING W AT 10 KT. MAINLY DEEP LAYER MODERATE MOISTURE ACCOMPANIES THE WAVE WHICH ALONG LOW LEVEL MOISTURE CONVERGENCE AND UPPER LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION E OF 68W...INCLUDING PUERTO RICO AND THE LESSER ANTILLES.

TROPICAL WAVE IS ON THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 22N82W TO 9N82W...MOVING W AT 10 KT. DRY AIR SUBSIDENCE FROM ALOFT IS HINDERING DEVELOPMENT OF DEEP CONVECTION AHEAD OF THE WAVE. SCATTERED MODERATE CONVECTION IS ON THE CENTRAL CARIBBEAN...INCLUDING JAMAICA AND HISPANIOLA.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 16N19W TO A 1010 MB LOW NEAR 17N25W TO 11N31W TO 10N41W 6N50W. ASIDE FROM CONVECTION OCCURRING WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 9N-15N BETWEEN 33W-40W.


...DISCUSSION...

GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL TROUGH ALONG THE EASTERN CONUS EXTENDS ITS BASE ACROSS THE EASTERN GULF AND THE FLORIDA PENINSULA. THIS TROUGH ALOFT SUPPORT A PAIR OF FRONTAL SYSTEMS...A STATIONARY FRONT ANALYZED ACROSS NORTHERN FLORIDA SW TO A 1013 NEAR 28N85W TO 25N90W AND A COLD FRONT ACROSS THE SE CONUS EXTENDING TO LOUISIANA. THIS FRONT IS FORECAST TO MERGE WITH THE STATIONARY FRONT ON TUESDAY. EAST AND WEST OF THE TROUGH ALOFT...RIDGING IS GENERATING DIFFLUENT FLOW WHICH ALONG ABUNDANT LOW-LEVEL MOISTURE BEING ADVECTED FROM THE CARIBBEAN SUPPORT SCATTERED MODERATE CONVECTION SOUTH OF THE STATIONARY FRONT E OF 90W. THE FRONT WILL DISSIPATE WED MORNING WHILE MOVING ACROSS CENTRAL FLORIDA. A TROPICAL WAVE MOVES INTO THE BAY OF CAMPECHE THU MORNING.

CARIBBEAN SEA...

TWO TROPICAL WAVES ARE IMPACTING THE CARIBBEAN THIS EVENING... ONE ALONG 64W AND THE OTHER ALONG 82W. THE EASTERN-MOST TROPICAL WAVE CONTINUES TO SUPPORT SHOWERS AND TSTMS ACROSS THE LESSER ANTILLES AND PUERTO RICO. THE WESTERN-MOST TROPICAL WAVE IS LARGELY PROVIDING SCATTERED SHOWERS TO THE OPEN WATERS OF THE CENTRAL CARIBBEAN AS WELL AS HISPANIOLA AND JAMAICA. SEE THE TROPICAL WAVES SECTION ABOVE. LOW LEVEL MOISTURE CONVERGENCE IS ENHANCING SCATTERED MODERATE CONVECTION ALONG CUBA. OTHERWISE...THE MONSOON TROUGH AXIS EXTENDS FROM COSTA RICA TO COLOMBIA WITH SCATTERED SHOWERS OCCURRING S OF 13N. THE TROPICAL WAVE ON THE EASTERN CARIBBEAN IS EXPECTED TO MOVE ACROSS HISPANIOLA AND CENTRAL BASIN TUE THROUGH WED MORNING.


...HISPANIOLA...

SCATTERED SHOWERS AND CLOUDY SKIES ARE ACROSS THE ISLAND TONIGHT BEING ENHANCED BY ABUNDANT MOISTURE TRAILING THE TROPICAL WAVE CURRENTLY OVER THE WESTERN CARIBBEAN. INCREASED CONVECTIVE ACTIVITY IS EXPECTED TUESDAY TO WED MORNING AS THE TROPICAL WAVE CURRENTLY OVER THE EASTERN CARIBBEAN MOVES ACROSS THE ISLAND AND ADJACENT WATERS.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE EASTERN CONUS THAT SUPPORTS A STATIONARY FRONT ANALYZED FROM 30N74W SW TO 29N81W AND THEN ACROSS THE NE GULF OF MEXICO. SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 23N W OF 73W ACROSS A PORTION OF THE SW NORTH ATLC...INCLUDING THE FLORIDA PENINSULA. THE FRONT IS EXPECTED TO MERGE WITH A COLD FRONT CURRENTLY TO THE NORTH ON TUESDAY. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 24N53W THAT SUPPORTS A BROAD AREA OF CLOUDINESS WITH EMBEDDED AREAS OF ISOLATED SHOWERS AND TSTMS OCCURRING FROM 24N-31N BETWEEN 46W-58W. THE TAIL END OF A FRONTAL BOUNDARY ANALYZED AS A STATIONARY FRONT FROM 27N43W TO 29N51W EXTENDS INTO THIS AREA OF CONVECTION PROVIDING ENHANCED FOCUS ON CONVECTION OCCURRING NEAR THE FRONT. TO THE EAST...A DISSIPATING COLD FRONT ENTERS THE DISCUSSION AREA NEAR 30N32W AND EXTENDS SW TO 27N42W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM EITHER SIDE OF THIS FRONT.

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

$$ NR

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