[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU AUG 14 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 CAME OFF THE WEST AFRICAN COAST EARLIER THIS
MORNING. CURRENTLY...ITS AXIS EXTENDS FROM 17N17W TO 9N16W WITH
AN EXPECTED MOTION OF 15 KT IN THE NEXT 24 HOURS. THE WAVE IS
EMBEDDED IN THE MONSOON TROUGH WHERE DEEP LAYER MOISTURE AND
UPPER-LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION
FROM 6N-16N E OF 20W.

A TROPICAL WAVE IS ON THE EASTERN ATLC WITH AXIS EXTENDING FROM
17N27W TO A 1012 MB LOW NEAR 11N27W TO 7N27W...MOVING W AT 10
KT. METEOSAT PSEUDO NATURAL AND SAL TRACKING IMAGERY INDICATE
SAHARAN DUST AND DRY AIR IN THE WAVE ENVIRONMENT N OF THE LOW
CENTER...WHICH IS SUPPRESSING CONVECTION IN THE NORTHERN AND
CENTRAL PORTIONS OF THE WAVE. SCATTERED MODERATE CONVECTION IS
MOSTLY LIMITED S OF THE MONSOON TROUGH FROM 5N-12N BETWEEN 25W-
34W.

A TROPICAL WAVE IS WEST OF THE MONSOON TROUGH WITH AXIS
EXTENDING FROM 17N47W TO 9N48W...MOVING W AT 20 KT. MODERATE
MOISTURE IS ASSOCIATED WITH THIS WAVE AT THE LOWER LEVELS.
HOWEVER...STRONG DRY AIR SUBSIDENCE ALOFT SUPPRESS CONVECTION.
ISOLATED SHOWERS ARE WITHIN 340 NM W OF THE WAVE AXIS FROM 11N-
17N.

A TROPICAL WAVE IS MOVING ACROSS THE YUCATAN PENINSULA AND
CENTRAL AMERICA WITH AXIS EXTENDING FROM 19N88W TO
9N89W...MOVING W AT 15 KT. THERE IS NO DEEP CONVECTION
ASSOCIATED WITH THIS WAVE. ISOLATED SHOWERS ARE OVER
BELIZE AND GUATEMALA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
12N16W TO 11N27W 9N38W TO 7N47W. THE INTERTROPICAL CONVERGENCE
ZONE AXIS BEGINS W OF A TROPICAL WAVE NEAR 10N51W AND CONTINUES TO
9N61W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTERED MODERATE CONVECTION IS WITHIN 115 NM S OF THE
MONSOON TROUGH BETWEEN 38W-48W.

...DISCUSSION...

GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL TROUGH CONTINUES ACROSS THE EASTERN
CONUS WITH BASE EXTENDING INTO THE NORTHERN GULF COASTLINE. THIS
TROUGH ALOFT SUPPORTS A FRONTAL SYSTEM ANALYZED AS A STATIONARY
FRONT FROM 30N82W SW TO 28N91W TO SOUTHERN TEXAS NEAR 27N97W. A
SURFACE PRE-FRONTAL TROUGH EXTENDS FROM NORTHERN FLORIDA NEAR
30N82W SW TO 27N90W TO 25N95W. SCATTERED HEAVY SHOWERS AND TSTMS
ASSOCIATED WITH THESE FEATURES ARE N OF 24N E OF 96W. SIMILAR
CONVECTION IS ON THE SE GULF N OF 23N E OF 85W BEING ENHANCED BY
LOW-LEVEL MOISTURE CONVERGENCE ALONG THE WESTERN FLORIDA COAST.
A MIDDLE-LEVEL INVERTED TROUGH IS OVER THE WESTERN GULF WHICH
SUPPORTS A SURFACE TROUGH ALONG 22N95W TO 18N94W AS WELL AS
SCATTERED MODERATE CONVECTION AND TSTMS S OF 24N W OF 92W. WEAK
SURFACE RIDGING DOMINATES ELSEWHERE ACROSS THE BASIN AND
PROVIDES VARIABLE WINDS OF 5-10 KT. THE STATIONARY FRONT IS
FORECAST TO DISSIPATE BY FRIDAY MORNING. SURFACE RIDGING WILL
DOMINATE ELSEWHERE FOR THE REST OF THE WEEKEND.

CARIBBEAN SEA...

THE TROPICAL WAVE FORMERLY ON THE FAR WESTERN CARIBBEAN IS NOW
MOVING ACROSS THE YUCATAN PENINSULA AND CENTRAL AMERICA. SEE
TROPICAL WAVE SECTION ABOVE. AN ELONGATED UPPER-LEVEL LOW IS ON THE
NW CARIBBEAN WHICH ALONG MODERATE DEEP LAYER MOISTURE SUPPORT
SCATTERED SHOWERS FROM 18N-20N BETWEEN 80W-86W. DEEP LAYER
MOISTURE IS ON THE SW BASIN WHICH ALONG UPPER LEVEL DIFFLUENCE
SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS S OF 15N W OF 78W.
FARTHER EAST...A 1011 MB LOW IS OFF THE COAST OF COLOMBIA NEAR
9N76W SUPPORTING SCATTERED SHOWERS S OF 13N BETWEEN 73W-78W.
ELSEWHERE...DRY AIR AND DUST ASSOCIATED WITH A SAHARAN AIRMASS
SUPPORT HAZE. A TIGHT PRESSURE GRADIENT ACROSS THE CENTRAL AND
SW CARIBBEAN SUPPORT TRADES OF 20-25 KT WITH WINDS UP TO 30 KT
ALONG THE COAST OF COLOMBIA. ELSEWHERE...TRADES OF 10-15 KT
DOMINATE. A NEW TROPICAL WAVE ENTERS THE E BASIN SATURDAY
MORNING.

HISPANIOLA...

MOSTLY DEEP LAYER DRY AIR IS ACROSS THE ISLAND WHICH IS
PROVIDING AN OVERALL STABLE ENVIRONMENT. A DRY SAHARAN AIRMASS
WILL CONTINUE TO MOVE ACROSS THE ISLAND THROUGH SATURDAY
AFTERNOON THUS SUPPORTING FAIR WEATHER BUT SOME HAZINESS.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL TROUGH CONTINUES ACROSS THE EASTERN
CONUS AND FAR WESTERN ATLC SUPPORTING A COLD FRONT N OF THE AREA
OF DISCUSSION AND A PRE-FRONTAL TROUGH EXTENDING FROM 32N73W TO
29N77W...ACROSS THE NORTHERN BAHAMAS TO 24N78W. HEAVY SHOWERS
AND TSTMS ASSOCIATED WITH THESE FEATURES ARE N OF 28N BETWEEN
74W-78W. SIMILAR CONVECTION IS NOTED FROM 22N-27N BETWEEN 74W-
78W AND FROM 24N-28N BETWEEN 64W-73W. THE CENTRAL AND EASTERN
ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A
1020 MB HIGH CENTERED NEAR 25N61W AND A PAIR OF HIGHS NEAR N-NE
OF THE AZORES ISLANDS.

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

$$
NR

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