[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT SEP 21 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 EXTENDS FROM 19N25W TO 12N24W MOVING W AT 10-15
KT. THE WAVE REMAINS EMBEDDED IN A MOIST SSMI TOTAL PRECIPITABLE
WATER VAPOR AREA. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM
OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 25N38W TO 16N39W MOVING W AT 10-15
KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES MOST OF THE WAVE
HAS FRACTURED AWAY FROM THE MOISTURE-LADEN MONSOON TROUGH REGION
AND IS EXPECTED TO BEGIN INTERACTION WITH A FRONTAL TROUGH TO
THE NW OVER THE NEXT FEW DAYS. NO SIGNIFICANT DEEP CONVECTION IS
NOTED ON SATELLITE IMAGERY AT THIS TIME WITH THE WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
12N24W TO A 1010 MB LOW NEAR 13N32W TO 11N42W TO 9N45W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 9N45W TO
10N53W. ISOLATED MODERATE CONVECTION IS FROM 6N-19N BETWEEN 20W-
32W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 2100 UTC...A COLD FRONT EXTENDS FROM S LOUISIANA AT 30N91W
TO A 1004 MB LOW OFF THE COAST OF S TEXAS NEAR 26N96W TO S OF
TAMPICO MEXICO AT 20N97W. SCATTERED MODERATE CONVECTION IS FROM
26N-30N BETWEEN 86W-94W... AND FROM 17N-27N BETWEEN 94W-98W. 20-
25 NORTHERLY WINDS ARE N OF THE FRONT OFF THE COAST OF TEXAS.
EXPECT THE FRONT IN 24 HOURS TO EXTEND FRON THE FLORIDA PANHADLE
TO THE NW GULF OF MEXICO TO THE SOUTHERN BAY OF CAMPECHE... WITH
CONTINUED CONVECTION.

CARIBBEAN SEA...

A LAX SURFACE PRESSURE GRADIENT IS OVER THE CARIBBEAN SEA WITH
10-15 KT WINDS. SCATTERED MODERATE CONVECTION IS OVER THE W
CARIBBEAN FROM 12N-21N BETWEEN 79W-83W. SCATTERED MODERATE
CONVECTION IS ALSO OVER PUERTO RICO...HISPANIOLA...CUBA...AND
JAMAICA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
ALSO INLAND OVER CENTRAL AMERICA FROM PANAMA TO BELIZE. IN THE
UPPER LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER CUBA.
UPPER LEVEL DIFFLUENCE IS OVER THE W CARIBBEAN S OF CUBA
ENHANCING THE CONVECTION. EXPECT OVER THE NEXT 24 HOURS FOR THE
TRADEWINDS TO INCREASE TO 20-25 KT OVER THE CENTRAL CARIBBEAN.
EXPECT LITTLE CHANGE IN CONVECTION OVER THE NEXT 24 HOURS.

HISPANIOLA...

PRESENTLY SCATTERED MODERATE CONVECTION IS OVER HISPANIOLA.
EXPECT SIMILAR CONVECTION TOMORROW EVENING DUE TO UPPER LEVEL
DIFFLUENCE AND EVENING AIRMASS HEATING.

ATLANTIC OCEAN...

A SURFACE TROUGH IS OVER THE W ATLANTIC FROM 30N73W TO THE N
BAHAMAS AT 25N76W. SCATTERED SHOWERS ARE E OF THE WAVE AXIS FROM
26N-31N BETWEEN 68W-74W. A 1004 MB LOW IS FURTHER E AT 29N62W
MOVING N. A SURFACE TROUGH EXTENDS SW FROM THE LOW TO 25N64W TO
THE S BAHAMAS AT 22N71W. SCATTERED MODERATE CONVECTION IS E OF
THE TROUGH AXIS FROM 20N-26N BETWEEN 58W-63W. A STATIONARY FRONT
IS OVER THE CENTRAL ATLANTIC FROM 31N50W TO 30N60W TO THE LOW AT
29N62W. SCATTERED MODERATE CONVECTION IS FROM 29N-32N BETWEEN
55W-59W. A SURFACE TROUGH IS OVER THE E ATLANTIC FROM 32N38W TO
28N45W. ISOLATED MODERATE CONVECTION IS 180 NM E OF THE TROUGH
AXIS. OF NOTE IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS
OVER THE W ATLANTIC W OF 60W. AN UPPER LEVELRIDGE IS OVER THE
CENTRAL ATLANTI N OF 25N BETWEEN 40W-60W. A SMALL UPPER LEVEL
LOW IS CENTERED OVER THE CENTRAL ATLANTIC AT 20N50W WITH STRONG
SUBSIDENCE. A LARGE UPPER LEVEL TROUGH IS OVER THE E ATLANTIC N
OF 10N E OF 40W. EXPECT OVER THE NEXT 24 HOURS FOR THE SURFACE
FRONT TO PRODUCE CONVECTION OVER THE W ATLANTIC N OF 25N AND W
OF 75W.

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

$$
FORMOSA


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