[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 12 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
2322 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE ASSOCIATED WITH A 1010 MB LOW EMBEDDED WITHIN
THE MONSOON TROUGH EXTENDS AN AXIS FROM 19N33W TO 11N33W WHICH
IS MOVING W NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW
THAT FOR THE MOST PART THE WAVE IS EMBEDDED IN A HIGH MOIST
ENVIRONMENT AT THE LOWER LEVELS. HOWEVER...METEOSAT SATELLITE
IMAGERY SHOW SAHARAN DUST AND DRY AIR SPREADING OVER THE WAVE
ENVIRONMENT N OF THE MONSOON TROUGH WHERE CONVECTIVE ACTIVITY IS
MINIMAL. SCATTERED MODERATE CONVECTION IS FROM 07N-11N BETWEEN
27W-36W.

A TROPICAL WAVE EXTENDS FROM 21N58W TO 11N56W MOVING W NEAR 15
KT. THE WAVE CONTINUES ON THE LEADING EDGE OF A SAHARAN DUST
OUTBREAK AND METEOSAT SATELLITE IMAGERY SHOW SOME DRY AIR
SPREADING OVER ITS ENVIRONMENT WHICH IS INHIBITING ANY DEEP
CONVECTION. ISOLATED RAINSHOWERS ARE WITHIN 170 NM EITHER SIDE
OF THE WAVE AXIS.

A DISTURBANCE IN THE CENTRAL CARIBBEAN IS NOW BEING ANALYZED AS
A TROPICAL WAVE WITH AXIS EXTENDING FROM 20N70W TO 12N73W. TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED IN A HIGH
MOIST ENVIRONMENT S OF 18N. SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS ARE FROM 13N-18N BETWEEN 66W-78W BEING AMPLIFIED
BY THE MONSOON TROUGH AXIS. THIS WAVE IS ALSO SUPPORTING SIMILAR
CONVECTION OVER HISPANIOLA.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
16N16W TO 13N28W 08N37W 07N45W. THE INTERTROPICAL CONVERGENCE
ZONE AXIS EXTENDS FROM 07N45W TO 08N52W. BESIDES THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE ALREADY DISCUSSED...A CLUSTER
OF MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-17N E OF 19W.
SCATTERED MODERATE CONVECTION IS WITHIN 110 NM EITHER SIDE OF A
LINE BETWEEN 20W-27W AND 36W-40W.

...DISCUSSION...

GULF OF MEXICO...
ANTICYCLONIC WIND FLOW IN THE RANGE OF 5-15 KT DOMINATES THE
GULF WATERS ANCHORED BY A 1018 MB HIGH NEAR 29N84W. IN THE SW
GULF...A SURFACE TROUGH THAT ENTERED EASTERN MEXICO EARLIER THIS
AFTERNOON CONTINUES TO ENHANCE ISOLATED SHOWERS SW OF A LINE
FROM 25N95W TO 19N92W. ANOTHER SURFACE TROUGH IS ALONG THE
YUCATAN PENINSULA TO GUATEMALA ENHANCING NUMEROUS MODERATE
CONVECTION AND TSTMS THAT EXTEND S OF 21N E OF 91W OVER THE BAY
OF CAMPECHE. AN UPPER LEVEL ANTICYCLONE CENTERED OVER NORTHERN
MEXICO AND ANOTHER CENTERED OVER THE SW N ATLC LEAVE A COL OR
AREA OF LOW PRESSURE BETWEEN ALABAMA AND LOUISIANA. THIS IS
SUPPORTING LOW LEVEL CONVERGENCE AND LIFTING OF MOIST AIR WHICH
IS ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS THAT
EXTENDS WITHIN 60 NM OFF THE NORTHERN GULF COAST BETWEEN 86W-
93W. OTHERWISE...FAIR WEATHER IS OVER THE REMAINDER BASIN
SUPPORTED BY DRY AIR IN THE LOWER AND MIDDLE LEVELS.

HIGH PRESSURE IS EXPECTED TO PERSISTS ACROSS THE BASIN WITHIN
THE NEXT 48 HOURS.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS CENTERED OVER THE YUCATAN CHANNEL AND
STRETCHES A TROUGH AXIS EASTWARD TO 22N66W. BOTH WATER VAPOR AND
TOTAL PRECIPITABLE WATER IMAGERY SHOW MODERATE MIDDLE TO LOWER
LEVELS MOISTURE IN THE WESTERN CARIBBEAN WHICH ALONG WITH THE
UPPER LOW SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED
TSTMS OVER CUBA AS WELL AS N OF 16N W OF 76W. A 1010 MB LOW NEAR
11N81W EMBEDDED WITHIN THE MONSOON TROUGH AXIS IS ENHANCING
NUMEROUS MODERATE CONVECTION FROM 11N-16N W OF 80W. THE AXIS OF
THE MONSOON TROUGH MOVES ACROSS COSTA RICA TO THE LOW TO 12N73W
WHICH IS ENHANCING SCATTERED SHOWERS S OF THE AXIS. A
DISTURBANCE IN THE CENTRAL CARIBBEAN IS NOW BEING ANALYZED AS A
TROPICAL WAVE WITH AXIS EXTENDING FROM 20N70W TO 12N73W.
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 13N-
18N BETWEEN 66W-78W BEING AMPLIFIED BY THE MONSOON TROUGH AXIS.
THIS WAVE IS ALSO SUPPORTING SIMILAR CONVECTION OVER HISPANIOLA.

RAINSHOWERS ARE EXPECTED TO PERSISTS ACROSS THE BASIN WITHIN THE
NEXT 48 HOURS ASSOCIATED WITH THIS TROPICAL WAVE AND A NEW WAVE
THAT IS EXPECTED TO ENTER THE EASTERN CARIBBEAN TUESDAY
AFTERNOON.

HISPANIOLA...
A TROPICAL WAVE IS MOVING ACROSS THE ISLAND THIS EVENING WITH
AXIS EXTENDING FROM 20N70W TO 12N73W. THE WAVE IS SUPPORTING
SCATTERED MODERATE CONVECTION AND TSTMS ACROSS THE ENTIRE ISLAND
AS WELL AS ADJACENT WATERS. RAINSHOWERS ASSOCIATED WITH THIS
WAVE ARE EXPECTED TO PERSIST UNTIL EARLY WEDNESDAY.

ATLANTIC OCEAN...
AS OF 2100 UTC...THE HIGH OVER THE SW N ATLC HAS DISSIPATED.
UPPER LEVEL DIFFLUENCE FROM THE UPPER LEVEL ANTICYCLONE OVER THE
SW N ATLC AND THE CYCLONIC CIRCULATION CENTERED OVER THE YUCATAN
CHANNEL IS ENHANCING RAINSHOWERS BETWEEN THE BAHAMAS AND THE
EASTERN FLORIDA PENINSULA FROM 23N-27N W OF 77W AS WELL AS THE
FLORIDA STRAITS. AN UPPER LEVEL LOW CENTERED NEAR 29N56W IS
SUPPORTING A SURFACE TROUGH ALONG 30N52W TO 24N55W. STRONG DEEP
LAYER ENVIRONMENTAL SHEAR MAINTAINS THE CONVECTION ASSOCIATED
WITH THIS TROUGH W OF IT...SCATTERED MODERATE FROM 24N-29N
BETWEEN 55W-62W. OTHERWISE...ASIDE FROM THE TROPICAL WAVES
ALREADY DISCUSSED ABOVE...SURFACE RIDGING AND DRY AIR IN THE
LOWER AND MIDDLE LEVELS SUPPORT FAIR WEATHER IN THE REMAINDER
BASIN.

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

$$
RAMOS

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