[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192323
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 19 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
2315 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE ALONG 29W EXTENDS FROM 5N-11N AND IS BASED ON
THE SATELLITE HOVMOLLER DIAGRAM AS WELL AS THE SUNY-ALBANY WAVE
DIAGNOSTICS FROM THE GFS. THE WAVE...HOWEVER...IS WEAK AND HAS A
RATHER NEGLIGIBLE SURFACE SIGNATURE.  NO DEEP CONVECTION IS
NOTED IN ASSOCIATION WITH THE WAVE.  THE WAVE WILL CONTINUE TO
MOVE WESTWARD AT ABOUT 15 KT.

A TROPICAL WAVE IS CURRENTLY AFFECTING THE LESSER ANTILLES WITH
SOME SHOWER ACTIVITY. IT EXTENDS AT THE SURFACE FROM 19N62W TO
11N62W MOVING W AT 15-20 KT. THE WAVE HAS A TURNING OF THE
SURFACE WINDS FROM SOUTHEAST TO EAST ACROSS THE AXIS AND IS
ACCOMPANIED BY A SURGE OF MOISTURE AS SEEN IN THE TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE ISOLATED DEEP
CONVECTION IS OCCURRING WITHIN 120 NM OF THE WAVE NORTH OF 17N.
IT APPEARS THAT THE 700 MB TROUGH AXIS IS SIGNIFICANTLY FARTHER
WEST...NEAR 71W.  MOISTURE ASSOCIATED WITH THE SURFACE COMPONENT
OF THE WAVE IS SPREADING ACROSS THE EASTERN CARIBBEAN IS
REACHING THE UK/US VIRGIN ISLANDS THIS EVENING...PUERTO RICO
EARLY ON FRIDAY...AND DOMINICAN REPUBLIC FRIDAY NIGHT INTO
SATURDAY. THIS SHOULD PROMOTE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS.

A TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA WITH AXIS ALONG
90W SOUTH OF 20N AND EXTENDS INTO THE EAST PACIFIC. THE WAVE IS
INDISTINCT ONLY IS TRACKABLE WITH THE SUNY-ALBANY TROUGH
DIAGNOSTICS. NO SIGNIFICANT DEEP CONVECTION IS IN ASSOCIATION
WITH THE WAVE...AS IT IS LOCATED WEST OF AN UPPER TROUGH...
PLACING IT WITHIN UPPER-LEVEL CONVERGENCE. THE WAVE AXIS WILL
CONTINUE TO MOVE WESTWARD ACROSS NORTHERN CENTRAL AMERICA AND SE
MEXICO DURING THE NEXT 24 HOURS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH ENTERS THE ATLANTIC ALONG THE THROUGH THE
COAST OF GUINEA-BISSAU NEAR 12N16W THEN CONTINUES TO 06N20W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N20W TO
06N28W THEN RESUMES W OF THE TROPICAL WAVE ALONG 29W FROM 5N31W
TO 2N50W AT THE COAST OF BRAZIL. SCATTERED MODERATE IS LOCATED
WITHIN 180 NM OF THE ITCZ AND MONSOON TROUGH EAST OF 28W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK SURFACE RIDGE IS LOCATED ALONG COAST AND THE RESULTING
SMALL PRESSURE GRADIENT IS FORCING EAST TO SOUTHEAST SURFACE
WINDS OF GENERALLY 15 KT OR LESS ACROSS THE GULF.  A WEAK
SURFACE TROUGH EXTENDS FROM 30N85W TO 26N87W.  WHILE THIS WAS
HELPING TO PROMOTE CONVECTION EARLIER TODAY...NO SIGNIFICANT
DEEP CONVECTION IS SEEN ACROSS THE GULF AT THIS TIME.  A POCKET
OF DRY AIR...PERHAPS A SAHARAN AIR LAYER...IS SEEN IN THE
SOUTHERN GULF OF MEXICO FROM BOTH THE TOTAL PRECIPITABLE WATER
IMAGERY AS WELL AS MURKY VISIBLE IMAGERY.  WEAK RIDGING SHOULD
MEANDER TO NEAR THE CENTRAL GULF DURING THE NEXT TWO DAYS AND
GENERALLY DRY CONDITIONS WILL PREVAIL.

CARIBBEAN SEA...
A MODERATE NORTH-SOUTH PRESSURE GRADIENT IS FORCING EASTERLY
TRADEWINDS ACROSS THE CARIBBEAN TODAY.  SEE DISCUSSION ABOVE
ABOUT THE EFFECT OF THE TROPICAL WAVE IN THE EASTERN CARIBBEAN.
ELSEWHERE...THE COMBINATION OF THE EASTERN PACIFIC MONSOON
TROUGH IMPINGING UPON THE SOUTHWESTERN CARIBBEAN SEA ALONG WITH
AN UPPER-LEVEL TROUGH ALONG 85W HAS PROMOTED SPORADIC CONVECTION
OVER SOUTHERN CENTRAL AMERICA AND THE SW CARIBBEAN.  CONTINUED
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE LIKELY IN THE
SAME VICINITY DURING THE NEXT COUPLE OF DAYS.

...HISPANIOLA...
RELATIVELY FEW SHOWERS AND THUNDERSTORMS OCCURRED TODAY OVER
HISPANIOLA...AS DRY CONDITIONS PREVAIL AHEAD OF THE TROPICAL
WAVE IN THE EASTERN CARIBBEAN. THIS WAVE AND ASSOCIATED DEEP
MOISTURE IS FORECAST TO BRING AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY BY SATURDAY...ENHANCING THE DIURNAL LATE
AFTERNOON-EARLY EVENING MAXIMUM IN CONVECTION.

ATLANTIC OCEAN...
A DISSIPATING STATIONARY FRONT IS ANALYZED FROM 31N57W TO
29N61W...AND THEN THE FEATURE BECOMES A TROUGH EXTENDING TO
26N71W. NO SIGNIFICANT DEEP CONVECTION IS OCCURRING ALONG THIS
BOUNDARY.  THE FRONT/TROUGH SHOULD DISSIPATE IN A DAY OR SO.  A
WEAK TROUGH AND EMBEDDED 1019 MB SURFACE LOW IS LOCATED JUST
EAST OF THE FLORIDA PENINSULA NEAR 28N80W. ISOLATED DEEP
CONVECTION IS LOCATED WITHIN 120 NM IN THE SOUTHERN SEMICIRCLE.
HOWEVER...THE FEATURE APPEARS TO SHORT-LIVED AND WILL LIKELY
DISSIPATE IN THE NEXT DAY OR SO.  FINALLY...A WEAK 1016 MB LOW
IS LOCATED NEAR 31N21W WITH A COLD FRONT EXTENDING TO ITS SOUTH
AND WEST.  THIS SHOULD PUSH EASTWARD WITHOUT REACHING MUCH
FARTHER SOUTH AND GRADUALLY WEAKEN.  ELSEWHERE...A PAIR OF 1025
MB SURFACE HIGHS AT 27N43W AND 30N34W ANCHOR A RIDGE THAT
EXTENDS ACROSS THE ATLANTIC NEAR 28N.  THE RESULTING MODERATE
PRESSURE GRADIENT ON THE EQUATORWARD SIDE ARE GENERALLY
PRODUCING EASTERLY TRADEWINDS OF ABOUT 15 KT.  LITTLE CHANGE IS
ANTICIPATED DURING THE NEXT COUPLE OF DAYS.

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

$$
LANDSEA


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