[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 13 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...

A TROPICAL WAVE IS ON THE EAST ATLC WITH AXIS EXTENDING FROM
19N22W TO 8N22W...MOVING W AT 10 KT. METEOSAT PSEUDO NATURAL AND
SAL TRACKING IMAGERY INDICATE SAHARAN DUST AND DRY AIR IN THE
WAVE ENVIRONMENT N OF 12N WHICH IS SUPPRESSING CONVECTION IN THE
NORTHERN AND CENTRAL PORTIONS OF THE WAVE. SCATTERED MODERATE
CONVECTION IS FROM 7N-12N BETWEEN 21W-30W...COINCIDING WITH A
REGION OF DEEP LAYER MOISTURE...A MIDDLE-LEVEL LOW AND UPPER-
LEVEL DIFFLUENCE.

A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM
20N39W TO 9N42W...MOVING W AT 15-20 KT. SSMI TPW AND METEOSAT
SAL TRACKING IMAGERY INDICATE SAHARAN DRY AIR IS IN THE WAVE
ENVIRONMENT N OF THE MONSOON TROUGH NEAR 11N WHICH IS
SUPPRESSING CONVECTION. SCATTERED MODERATE CONVECTION IS
OCCURRING SW OF THE WAVE AXIS FROM 7N-9N BETWEEN 42W-46W.

A TROPICAL WAVE IS ON THE FAR WESTERN CARIBBEAN WITH AXIS
EXTENDING FROM 18N82W TO 8N82W...MOVING W AT 20 KT. MODERATE
MOISTURE CONTINUES TO BE ASSOCIATED WITH THIS WAVE WHICH IS
CONVERGING ALONG THE COASTLINE OF CENTRAL AMERICA TO ENHANCE
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS S OF 19N
BETWEEN 80W-85W. SE OF THE WAVE AXIS SIMILAR CONVECTION OCCURS S
OF 11N BETWEEN 76W-82W.

A TROPICAL WAVE IS MOVING ACROSS SOUTHERN MEXICO WITH AXIS
EXTENDING FROM THE BAY OF CAMPECHE NEAR 22N95W TO E PAC WATERS
NEAR 14N96W...MOVING W AT 5-10 KT. A MIDDLE TO UPPER LEVEL
INVERTED TROUGH SUPPORT THIS WAVE AS WELL AS ISOLATED SHOWERS
AND TSTMS S OF 25N W OF 93W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
14N17W TO 11N30W 12N36W TO 10N43W. THE INTERTROPICAL CONVERGENCE
ZONE AXIS BEGINS NEAR 9N44W AND CONTINUES ALONG 8N53W TO 9N61W.
BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTERED MODERATE CONVECTION IS FROM 6N-11N E OF 20W
AND FROM 7N-11N W OF 57W.

...DISCUSSION...

GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL TROUGH CONTINUES ACROSS THE EASTERN
CONUS WITH BASE EXTENDING INTO THE NORTHERN GULF N OF 27N. THIS
TROUGH ALOFT SUPPORTS A COLD FRONT FROM A 1004 MB LOW OVER NEW
YORK SW ALONG THE SE CONUS COASTLINE TO PENSACOLA FLORIDA TO
28N90W 28N96W. IT ALSO SUPPORTS A SURFACE PRE-FRONTAL TROUGH
EXTENDING FROM 29N83W TO 27N90W 27N95W...THUS ENHANCING ISOLATED
SHOWERS AND TSTMS N OF 26N E OF 95W. A TROPICAL WAVE IS MOVING
ACROSS SOUTHERN MEXICO WITH AXIS EXTENDING FROM THE BAY OF
CAMPECHE TO EAST PACIFIC WATERS. THIS WAVE IS BEING SUPPORTED BY
A MIDDLE TO UPPER LEVEL INVERTED TROUGH OVER THE SW GULF THAT
ENHANCES SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS S OF
26N W OF 92W. SEE THE TROPICAL WAVES SECTION ABOVE FOR MORE
DETAILS. FARTHER EAST IN THIS PORTION OF THE GULF...A SURFACE
TROUGH IS FROM 23N89W TO 18N92W ENHANCING SHOWERS AND TSTMS FROM
23N-25N BETWEEN 88W-91W. WEAK SURFACE RIDGING DOMINATES
ELSEWHERE ACROSS THE BASIN AND PROVIDES VARIABLE WINDS OF 5-10
KT. NO SIGNIFICANT CHANGES ACROSS THE GULF ARE EXPECTED THROUGH
THU MORNING. BY FRIDAY MORNING...THE FRONTAL BOUNDARY ON THE N-
NE GULF IS FORECAST TO DISSIPATE.

CARIBBEAN SEA...

A TROPICAL WAVE IS MOVING ACROSS THE FAR WESTERN CARIBBEAN BEING
SUPPORTED BY AN UPPER-LEVEL INVERTED TROUGH. MODERATE DEEP LAYER
MOISTURE IS ASSOCIATED WITH THIS WAVE WHICH IS SUPPORTING
SCATTERED MODERATE CONVECTION AND TSTMS S OF 19N BETWEEN 80W-
85W. SEE THE WAVES SECTION ABOVE FOR MORE DETAILS. THE MONSOON
TROUGH EXTENDING TO NORTHERN COLOMBIA SUPPORT HEAVY SHOWERS AND
TSTMS S OF 11N BETWEEN 76W-82W. ELSEWHERE...DEEP LAYER DRY AIR
SUPPORT FAIR WEATHER. OVER THE EASTERN BASIN...DUST AND HAZINESS
ARE BEING REPORTED BY SOME OF THE LESSER ANTILLES BEING
ASSOCIATED WITH A SAHARAN AIRMASS MOVING ACROSS THE REGION.
TRADES OF 15 KT ARE ACROSS THE EASTERN BASIN WHILE WINDS UP TO
10 KT DOMINATE OVER THE WESTERN CARIBBEAN. ON THE CENTRAL
BASIN...A TIGHTER PRESSURE GRADIENT SUPPORT TRADES UP TO 20 KT.
THE TROPICAL WAVE IS FORECAST TO MOVE INTO CENTRAL AMERICA BY
THU MORNING. A NEW TROPICAL WAVE ENTERS THE E BASIN FRIDAY.

HISPANIOLA...

MOSTLY DEEP LAYER DRY AIR IS ACROSS THE ISLAND WHICH IS
PROVIDING AN OVERALL STABLE ENVIRONMENT. HOWEVER...SOME
CLOUDINESS ARE ACROSS THE WESTERN COAST BEING SUPPORTED BY
LINGERING MOISTURE FROM THE WAVE OVER THE W CARIBBEAN. A DRY
SAHARAN AIRMASS WILL MOVE ACROSS THE ISLAND LATER TODAY THROUGH
EARLY THIS WEEKEND THUS SUPPORTING FAIR WEATHER BUT SOME
HAZINESS.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL TROUGH IS ACROSS THE EASTERN CONUS AND
THE FAR WESTERN ATLC. THIS TROUGH ALOFT SUPPORTS A SURFACE PRE-
FRONTAL TROUGH EXTENDING FROM 30N81W...ACROSS NORTHERN FLORIDA
AND NORTHERN GULF. SCATTERED MODERATE CONVECTION AND ISOLATED
TSTMS ARE N OF 28N BETWEEN 77W-79W. FARTHER EAST...THE TAIL OF A
COLD FRONT EXTENDS FROM 30N45W TO 28N47W. FINALLY...THE CENTRAL
AND EASTERN ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1022 MB HIGH CENTERED NEAR 26N55W.

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

$$
NR

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