[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE SEP 23 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 ON THE EASTERN ATLC WITH AXIS EXTENDING FROM
22N27W TO A 1011 MB LOW NEAR 17N28W TO 12N29W...MOVING W AT 10
KT. THE GOES-R SEVIRI AIRMASS PRODUCT DEPICT WARM DRY AIR IN THE
WAVE ENVIRONMENT...ALSO CONFIRMED IN THE METEOSAT SAL AND THE
SSMI TPW IMAGERY. SAHARAN DUST IS ALSO IN THE NORTHERN AND
WESTERN WAVE ENVIRONMENT AS DEPICTED IN THE GOES-R DUST PRODUCT.
AS A RESULT CONVECTION REMAINS MINIMAL AND NE OF THE WAVE AXIS
AS SCATTERED MODERATE WITH ISOLATED TSTMS FROM 17N-23N BETWEEN
21W-27W.

A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM
19N48W TO 10N50W...MOVING W AT 15-20 KT. THE GOES-R SEVIRI
AIRMASS PRODUCT DEPICT DRY CONDITIONS AT HIGH LEVELS IN THE
CENTRAL AND SOUTHERN WAVE ENVIRONMENT...WHICH SUBSIDENCE IS
SUPPRESSING CONVECTION. METEOSAT SAL TRACKING IMAGERY ALSO SHOW
SAHARAN DRY AIR IN THE NORTHERN WAVE ENVIRONMENT...HOWEVER THE
GOES-R DUST PRODUCT SHOW MINIMAL DUST IN THE WAVE.

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 23N71W TO 12N70W...MOVING W AT 15 KT. HIGH MIDDLE
TO LOWER LEVELS MOISTURE IS BEHIND THE WAVE AXIS ACROSS THE
EASTERN CARIBBEAN WHILE DEEP LEVEL MOISTURE IS ACROSS
HISPANIOLA. HEAVY SHOWERS AND TSTMS ARE ACROSS HISPANIOLA WHILE
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE E OF THE
WAVE AXIS ACROSS THE BASIN...INCLUDING THE LEEWARD ISLANDS.

A TROPICAL WAVE IS MOVING ACROSS THE YUCATAN PENINSULA AND
CENTRAL AMERICA WITH AXIS EXTENDING FROM 21N90W TO 12N87W. THE
WAVE IS ASSOCIATED WITH MODERATE MIDDLE TO UPPER-LEVEL MOISTURE
BUT HIGH MOISTURE IN THE UPPER LEVEL AS DEPICTED IN WATER VAPOR
IMAGERY. UPPER LEVEL DIFFLUENCE EAST OF THE BASE OF AN UPPER
LEVEL TROUGH EXTENDING ACROSS THE EASTERN GULF TO THE YUCATAN
SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS ACROSS THE
YUCATAN PENINSULA AND CHANNEL AS WELL AS NORTHERN CENTRAL
AMERICA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 17N16W TO
A 1012 MB LOW CENTERED NEAR 10N21W TO 8N24W. IT THEN RESUMES
NEAR 13N30W TO 11N37W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 11N37W TO 12N44W TO 08N52W. ASIDE FROM CONVECTION
OCCURRING WITH THE TROPICAL WAVES...SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS ARE FROM 4N-15N BETWEEN 20W-
28W...AND FROM 12N-16N BETWEEN 40W-45W.

...DISCUSSION...

GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL LOW IS ON THE CAROLINAS EXTENDING A
TROUGH ACROSS THE FLORIDA PENINSULA AND EASTERN GULF AND
SUPPORTING A FRONTAL BOUNDARY ANALYZED AS A COLD FRONT ON THE SW
N ATLC TO THE EASTERN COAST OF CENTRAL FLORIDA. FROM THERE THE
FRONT TRANSITIONS TO A STATIONARY BOUNDARY FROM 27N82W SW TO THE
CENTRAL GULF NEAR 25N90W TO 24N92W. SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS ARE WITHIN 100 NM EITHER SIDE OF
THE FRONT. A TROPICAL WAVE IS MOVING ACROSS THE YUCATAN PENINSULA
AND NORTHERN CENTRAL AMERICA ENHANCING SIMILAR CONVECTION IN
THAT REGION AND IN THE YUCATAN CHANNEL. OTHERWISE...A BROAD
SURFACE HIGH PRESSURE ON THE NE CONUS EXTENDS A RIDGE S-SW TO
THE N AND WESTERN GULF WHERE DRY AIR SUBSIDENCE INHIBITS
CONVECTIVE ACTIVITY. THE STATIONARY FRONT WILL WEAKEN BUT
PREVAIL ACROSS THE FLORIDA PENINSULA THROUGH FRIDAY MORNING
WHILE THE TROPICAL WAVE MOVES ACROSS THE BAY OF CAMPECHE ENHANCING
SHOWERS.

CARIBBEAN SEA...

DEEP LAYER TRAILING MOISTURE ASSOCIATED WITH THE PASSAGE OF A
TROPICAL WAVE CONTINUES TO ENHANCE SCATTERED SHOWERS AND ISOLATED
TSTMS ACROSS THE WESTERN BASIN W OF 73W. A TROPICAL WAVE IS ON THE
CENTRAL CARIBBEAN WITH AXIS ALONG 71W WITH HIGH MIDDLE TO LOWER
LEVELS TRAILING MOISTURE SUPPORTING SCATTERED SHOWERS AND
ISOLATED TSTMS E OF THE AXIS. HOWEVER A REGION OF DIFFLUENCE
ALOFT IS SUPPORTING HEAVY SHOWERS AND TSTMS ACROSS HISPANIOLA
AND ADJACENT WATERS. THIS WAVE WILL CONTINUE TO BRING SHOWERS TO
HISPANIOLA THROUGH THURSDAY. THE NEXT TROPICAL WAVE WILL ENTER THE
EASTERN CARIBBEAN FRIDAY MORNING.

...HISPANIOLA...

CURRENTLY...A TROPICAL WAVE LIES ALONG 71W BRINGING HEAVY
SHOWERS AND TSTMS ACROSS THE ISLAND AND ADJACENT WATERS.
CONVECTIVE ACTIVITY ASSOCIATED WITH THE WAVE IS FORECAST THROUGH
WED.

ATLANTIC OCEAN...

AN ELONGATED MIDDLE TO UPPER LEVEL TROUGH IS OVER THE EASTERN
CONUS SUPPORTING A FRONTAL BOUNDARY ANALYZED AS A COLD FRONT
ALONG 30N78W TO THE EASTERN COAST OF CENTRAL FLORIDA WHERE IT
TRANSITIONS INTO A STATIONARY FRONT ACROSS THE NE GULF OF
MEXICO. SCATTERED MODERATE CONVECTION AND TSTMS ARE OCCURRING N
OF 26N W OF 77W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED
NEAR 25N55W THAT SUPPORTS A BROAD AREA OF CLOUDINESS WITH
EMBEDDED AREAS OF ISOLATED SHOWERS AND TSTMS OCCURRING FROM 23N-
30N BETWEEN 50W-60W. A MIDDLE TO UPPER LEVEL TROUGH ACROSS THE
REMAINDER CENTRAL AND EASTERN ATLC SUPPORT A SURFACE TROUGH
ALONG 29N30W TO 28N37W TO 26N43W WITH SCATTERED SHOWERS OCCURRING
FROM 28N-31W BETWEEN 27W-31W.

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

$$
NR


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