[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 281753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN SEP 28 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 CENTRAL ATLANTIC WITH AXIS EXTENDING FROM
16N31W TO 7N32W...MOVING W AT 15-20 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 TSTMS FROM 12N-
17N BETWEEN 29W-36W. 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 22N75W TO 10N76W...MOVING WESTWARD AT 15 KT. THE WAVE IS
BEING SUPPORTED BY A MIDDLE LEVEL INVERTED TROUGH AND AN
ELONGATED UPPER LEVEL LOW WHICH ALONG DEEP LAYER MODERATE
MOISTURE SUPPORT SCATTERED MODERATE CONVECTION FROM 12N-16N
BETWEEN 73W-78W AND ISOLATED SHOWERS AND TSTMS ACROSS
HISPANIOLA. THE REMAINDER WAVE ENVIRONMENT IS DEVOID OF
CONVECTION DUE IN PART TO STRONG DEEP LAYER ENVIRONMENTAL SHEAR
IN THE CENTRAL AND EASTERN CARIBBEAN BASIN.

A TROPICAL WAVE IS MOVING ACROSS THE BAY OF CAMPECHE...SOUTHERN
MEXICO AND E PAC WATERS WITH AXIS EXTENDING FROM 22N95W TO
12N96W...MOVING W AT 5 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 22N W OF 91W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO
5N22W TO 5N29W. THE ITCZ EXTENDS FROM 5N30W TO 4N41W TO 7N50W.
SCATTERED MODERATE CONVECTION IS FROM 3N-11N E OF 19W.

...DISCUSSION...

GULF OF MEXICO...

A STATIONARY FRONT EXTENDS ACROSS NORTHERN FLORIDA AND THE
NORTHERN GULF ALONG 29N83W TO 28N90W TO A 1012 MB LOW NEAR
26N96W. IN THE UPPER-LEVELS THE EASTERN PERIPHERY OF A RIDGE
ANCHORED OVER MEXICO COVERS THE WESTERN GULF WHILE THE REMAINDER
BASIN AND THE FLORIDA PENINSULA IS UNDER THE INFLUENCE OF
ANOTHER RIDGE ANCHORED NEAR 26N82W. THIS RIDGES ARRANGEMENT IN
THE UPPER LEVELS IS GENERATING A DIFFLUENT ENVIRONMENT THAT
ALONG DEEP LAYER HIGH MOISTURE SUPPORT SCATTERED MODERATE
CONVECTION AND TSTMS N OF 26N BETWEEN 83W-95W AND IN THE BAY OF
CAMPECHE. 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 REMAIN STATIONARY ACROSS THE
NORTHERN BASIN THROUGH MONDAY MORNING WHILE THE WAVE CONTINUES
TO MOVE W TO INLAND MEXICO AND THEN INTO THE PACIFIC WATERS.

CARIBBEAN SEA...

AN ELONGATED UPPER-LEVEL LOW IS CENTERED SW OF HAITI EXTENDING A
TROUGH AXIS SW INTO THE SW CARIBBEAN AND NE ACROSS HISPANIOLA TO
THE SW N ATLC WATERS WHILE N-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. A SLIGHT TIGHTENING OF THE PRESSURE GRADIENT DUE TO THE
PASSAGE OF THE TROPICAL WAVE SUPPORT TRADES OF 15-20 KT ACROSS THE
CENTRAL BASIN WHILE WINDS OF 10 KT DOMINATE ELSEWHERE. THE
TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA
BY MONDAY NIGHT.

...HISPANIOLA...

A TROPICAL WAVE IS W OF HISPANIOLA WHILE AN UPPER LEVEL LOW
REMAINS NEARLY STATIONARY OVER THE AREA. SCATTERED SHOWERS AND
THUNDERSTORMS ARE OCCURRING ACROSS HISPANIOLA AND OFFSHORE
WATERS. ALTHOUGH THE WAVE WILL SHIFT WEST OF THE REGION...A
MOIST AIRMASS AND THE PRESENCE OF THE UPPER LOW WILL SUPPORT
CONVECTION FOR THE NEXT 24 HOURS WITH LOCALIZED FLOODING AND
POSSIBLE MUDSLIDES.

ATLANTIC OCEAN...

A STATIONARY FRONT IS ANALYZED FROM 30N80W TO 30N81W...ACROSS
NORTHERN FLORIDA INTO THE NORTHERN GULF WITH ISOLATED SHOWERS
WITHIN 50 NM EITHER SIDE OF THE FRONT IN THE ATLC. A DIFFLUENT
ENVIRONMENT IN THE MIDDLE LEVELS GENERATED BY AN INVERTED TROUGH
EXTENDING FROM THE SOUTHERN BAHAMAS SW INTO THE CARIBBEAN AND AN
ANTICYCLONE ANCHORED OVER THE CENTRAL LESSER ANTILLES SUPPORT
SCATTERED SHOWERS AND TSTMS FROM 20N-25N BETWEEN 63W-73W.
SIMILAR CONVECTION IS N OF 28N BETWEEN 57W-64W. A BROAD UPPER-
LEVEL TROUGH IS OVER THE CENTRAL ATLC AND SUPPORTS THREE LOW
PRESSURE CENTERS WITH LITTLE TO NONE CONVECTION ASSOCIATED WITH
IT...A 1015 MB LOW NEAR 29N45W...A 1015 MB LOW NEAR 24N50W AND A
1015 MB LOW NEAR 14N43W. OTHERWISE...A TROPICAL WAVE IS OVER
THE CENTRAL ATLC. SEE THE TROPICAL WAVES SECTION.

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

$$
NR


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