[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 27 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 IN THE E ATLANTIC WITH AXIS EXTENDING FROM
16N23W TO 5N24W MOVING W AT 15 KT. THE SSMI TPW AND WATER VAPOR
IMAGERY SHOW PATCHES OF HIGH DEEP LAYER MOISTURE COINCIDING WITH
A REGION OF MIDDLE TO UPPER LEVEL DIFFLUENCE THAT ENHANCES
SCATTERED MODERATE CONVECTION AND ISOLATED CONVECTION FROM 11N-
14N BETWEEN 23W-28W. THE GOES-R AIRMASS PRODUCT SHOW MIDDLE TO
UPPER LEVEL DRY AIR IN THE REMAINDER WAVE ENVIRONMENT...WHICH IS
DEVOID OF CONVECTION.

A TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN WITH AXIS EXTENDING
FROM 22N70W TO 11N70W...MOVING WESTWARD AT 15 KT. THE WAVE IS
BEING SUPPORTED BY A MIDDLE LEVEL INVERTED TROUGH AND AN UPPER
LEVEL LOW WHICH ALONG DEEP LAYER MODERATE MOISTURE SUPPORT
SCATTERED MODERATE CONVECTION FROM 13N-22N BETWEEN 58W-73W.

A TROPICAL WAVE IS MOVING ACROSS THE BAY OF CAMPECHE...SOUTHERN
MEXICO AND E PAC WATERS WITH AXIS EXTENDING FROM 24N93W TO
10N93W...MOVING W AT 10 TO 15 KT. A MIDDLE-LEVEL INVERTED TROUGH
SUPPORT THIS WAVE WHILE DEEP LAYER HIGH MOISTURE AND AN UPPER-
LEVEL DIVERGENT ENVIRONMENT ENHANCE SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS S OF 17N BETWEEN 89W AND 97W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 8N13W TO
7N24W TO 6N33W. THE ITCZ EXTENDS FROM 6N34W TO 6N47W. ISOLATED
MODERATE CONVECTION IS FROM 2N-9N BETWEEN 26W-35W.

...DISCUSSION...

GULF OF MEXICO...

A STATIONARY FRONT EXTENDS ACROSS NORTHERN FLORIDA AND THEN IN
THE NORTHERN GULF ALONG 29N83W TO 28N90W TO 25N96W. IN THE UPPER-
LEVELS THE EASTERN PERIPHERY OF A RIDGE ANCHORED OVER MEXICO
COVERS THE SOUTHERN GULF WHILE THE WESTERN PERIPHERY OF A RIDGE
ANCHORED ON CENTRAL FLORIDA IS OVER THE REMAINDER GULF. THIS
RIDGE ARRANGEMENT IN THE UPPER LEVELS IS GENERATING A DIFFLUENT
ENVIRONMENT THAT ALONG DEEP LAYER HIGH MOISTURE SUPPORT
SCATTERED MODERATE CONVECTION AND TSTMS N OF 24N BETWEEN 83W-90W
AND WITHIN 100 NM EITHER SIDE OF THE FRONT W OF 90W. IN THE SW
GULF...A MIDDLE-LEVEL INVERTED TROUGH SUPPORT A TROPICAL WAVE. SEE
THE TROPICAL WAVES SECTION FOR MORE DETAILS. THE FRONT IS
FORECAST TO TRANSITION INTO A WARM FRONT AND BE OVER THE
NORTHERN GULF COASTLINE BY SUNDAY MORNING WHILE THE WAVE
CONTINUES TO MOVE ACROSS THE E PAC WATERS LEAVING SHOWERS
INLAND MEXICO.

CARIBBEAN SEA...

AN ELONGATED UPPER-LEVEL LOW IS CENTERED ON THE MONA PASSAGE
EXTENDING A TROUGH AXIS SW INTO THE SW CARIBBEAN WHILE NE WIND
FLOW COVERS THE REMAINDER WESTERN BASIN. THE LOW ALOFT SUPPORT A
TROPICAL WAVE AND ASSOCIATED CONVECTION. SEE THE TROPICAL WAVES
SECTION FOR MORE DETAILS. OTHERWISE...A WEAK PRESSURE GRADIENT
ACROSS THE REGION SUPPORT TRADES OF 10-15 KT. THE TROPICAL WAVE IS
FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA BY MONDAY NIGHT.

...HISPANIOLA...

SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE OVER HISPANIOLA AND
OFFSHORE WATERS AS AN UPPER LOW INTERACTS WITH A TROPICAL WAVE
MOVING ACROSS THE ISLAND. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO CONTINUE OVER THE WEEKEND AS THE UPPER LOW REMAINS NEARLY
STATIONARY WHILE THE TROPICAL WAVE CONTINUES TO MOVE WESTWARD.

ATLANTIC OCEAN...

A STATIONARY FRONT IS ANALYZED FROM 30N79W TO 29N81W...ACROSS
NORTHERN FLORIDA INTO THE NORTHERN GULF. SCATTERED SHOWERS ARE N
OF 29N W OF 80W. THIS FRONT IS EXPECTED TO GRADUALLY DISSIPATE
OVER THE WEEKEND. AN UPPER-LEVEL TROUGH IS OVER THE CENTRAL ATLC
SUPPORT THREE LOW PRESSURE CENTERS WITH LITTLE TO NONE
CONVECTION ASSOCIATED WITH IT...A 1015 MB LOW NEAR 29N47W...A
1015 MB LOW NEAR 23N36W AND A 1013 MB LOW NEAR 13N43W.
OTHERWISE...TWO TROPICAL WAVES ARE AFFECTING THE BASIN. SEE THE
TROPICAL WAVES SECTION.

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

$$
NR


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