[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT OCT 19 2013

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
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE JUST SW OF THE CAPE VERDE ISLANDS EXTENDS FROM
15N26W TO 07N27W...MOVING W NEAR 10 KT. MIMIC TOTAL PRECIPITABLE
WATER IMAGERY CLEARLY INDICATES THE WAVE WITH A MAXIMUM JUST
EAST OF THE WAVE AXIS.  SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS WITHIN 180 NM OF THE WAVE AXIS BETWEEN 08N AND
14N.

TROPICAL WAVE APPROACHING THE WINDWARD ISLANDS EXTENDS FROM
16N58W TO 08N58W...MOVING W-NW NEAR 5 KT. MIMIC TOTAL
PRECIPITABLE WATER IMAGERY INDICATES AN INVERTED V STRUCTURE TO
THE TROPICAL WAVE.  SCATTERED MODERATE CONVECTION IS OCCURRING
WITHIN 120 NM OF THE WAVE AXIS BETWEEN 12N AND 15N.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLANTIC NEAR 13N15W TO 10N20W. THE ITCZ AXIS BEGINS W
OF A TROPICAL WAVE NEAR 08N30W AND CONTINUES TO 03N51W.  BESIDES
THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...SCATTERED
MODERATE CONVECTION IS FROM 07N-10N BETWEEN 35W-42W AND FROM 08N-
12N BETWEEN 48W-53W. THE NORTHEAST PACIFIC MONSOON TROUGH
EXTENDS ACROSS SOUTHERN CENTRAL AMERICA ENTERING THE CARIBBEAN
SEA AT 11N84W AND EXTENDING EAST-SOUTHEASTWARD TO COLOMBIA AT
09N76W.  SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
OCCURRING WITHIN 180 NM OF THE TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...
AT 2100 UTC...A STATIONARY FRONT OVER NE FLORIDA TRANSITIONS TO
A COLD FRONT IN THE NE GULF OF MEXICO NEAR 29N84W.  THE COLD
FRONT EXTENDS FROM THERE SOUTHWESTWARD ACROSS THE GULF OF MEXICO
TO THE MEXICAN COAST NEAR 20N97W.  SCATTERED MODERATE CONVECTION
IS OCCURRING WITHIN 60 NM OF THE FRONT SOUTH OF 25N AND
SCATTERED SHOWERS ARE OCCURRING WITHIN 60 NM OF THE FRONT NORTH
OF 25N.  A PRE-FRONTAL SURFACE TROUGH EXISTS IN THE EASTERN GULF
OF MEXICO FROM 28N83W TO 24N85W.  SCATTERED SHOWERS ARE
OCCURRING WITHIN 120 NM EAST OF THE TROUGH. A SECOND COLD FRONT
HAS ENTERED THE GULF OF MEXICO AND EXTENDS FROM SW LOUISIANA
NEAR 30N94W SOUTH-SOUTHWESTWARD TO THE MEXICAN COAST NEAR
24N98W.  NO SIGNIFICANT CONVECTION OR SHOWERS ARE LOCATED WITH
THIS FEATURE.

THE SECOND COLD FRONT IS EXPECTED TO OVERRIDE AND REINFORCE THE
COLD FRONT ACROSS THE CENTRAL GULF TONIGHT. THE MERGED COLD
FRONT WILL CONTINUE TO MOVE SOUTHEASTWARD TOWARDS THE
EASTERN GULF BEFORE STALLING AND WEAKENING BY MONDAY.

CARIBBEAN SEA...
MOST DEEP CONVECTION OVER THE CARIBBEAN IS RESTRICTED TO THAT IN
ASSOCIATION WITH THE TROPICAL WAVE APPROACHING THE WINDWARD
ISLANDS AND SOUTHWESTERNMOST CARIBBEAN IN ASSOCIATION WITH THE
MONSOON TROUGH...AS DISCUSSED EARLIER.  ISOLATED MODERATE
CONVECTION IS OCCURRING ALONG THE LEEWARD AND VIRGIN ISLANDS IN
ASSOCIATION WITH A SURFACE TROUGH/UPPER LEVEL LOW NORTH OF
PUERTO RICO.  THE REMAINDER OF THE CARIBBEAN SEA IS CONVECTION
FREE.  THERE ARE SOME SCATTERED THUNDERSTORMS OCCURRING OVER THE
GREATER ANTILLES AND NUMEROUS THUNDERSTORMS OCCURRING OVER
CENTRAL AMERICA AND MEXICO SOUTH OF 23N.  THESE ARE PRIMARILY
DUE TO LATE AFTERNOON HEATING AND SHOULD DIMINISH OVERNIGHT WITH
THE TYPICAL DIURNAL MINIMUM.

A WEAK PRESSURE GRADIENT PATTERN WILL PERSIST FOR THE NEXT FEW
DAYS. THE SURFACE TROUGH/UPPER LOW NORTH OF PUERTO RICO MAY
PERSIST FOR ANOTHER DAY OR TWO ENHANCING SHOWERS IN THE
NORTHEASTERN CARIBBEAN AS IT INTERACTS WITH THE APPROACHING
TROPICAL WAVE. THIS WAVE SHOULD REACH THE SOUTH CENTRAL
CARIBBEAN BY LATE MONDAY AND THE SW CARIBBEAN BY WEDNESDAY.

HISPANIOLA...
SCATTERED THUNDERSTORMS HAVE BEEN OCCURRING OVER HISPANIOLA THIS
AFTERNOON...WHICH ARE PRIMARILY DUE TO LATE AFTERNOON HEATING
AND SHOULD DIMINISH OVERNIGHT WITH THE TYPICAL DIURNAL MINIMUM.
THIS CONVECTIVE ACTIVITY SHOULD CONTINUE WITH THIS PATTERN FOR
THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...
A WEAK 1013 MB SURFACE LOW IS NE OF THE BAHAMAS NEAR 27N74W WITH
NO CONVECTION ASSOCIATED WITH IT. THIS SHOULD DISSIPATE ON
SUNDAY. FARTHER EAST...AN UPPER-LEVEL LOW IS CENTERED NEAR
23N64W AND IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM
NEAR PUERTO RICO NORTHWARD TO 22N66W.  THIS UPPER LEVEL
LOW/SURFACE TROUGH IS ENHANCING SCATTERED SHOWERS AND
THUNDERSTORMS NEAR THE VIRGIN ISLANDS FROM 18N-22N BETWEEN 60W-
65W.  A SECOND SURFACE TROUGH EXTENDS FROM 22N56W TO 26N51W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OCCURRING
WITHIN 180 NM OF THE TROUGH AXIS.  THIS TROUGH SHOULD MOVE
NORTHWARD WITHOUT MUCH LIKELIHOOD OF TROPICAL DEVELOPMENT.  A
SURFACE RIDGE DOMINATES THE REMAINDER OF THE CENTRAL AND EASTERN
ATLANTIC ANCHORED BY A 1020 MB HIGH IN THE CENTRAL ATLANTIC NEAR
28N34W.

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

$$
LANDSEA


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