[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 140005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI
FL 805 PM EDT TUE AUG 13 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.

...SPECIAL FEATURES...
A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS
EXTENDING FROM 21N78W TO A 1008 MB LOW NEAR 15N82W AND MOVING W-
NW NEAR 10 KT. THE WAVE IS EMBEDDED IN A HIGH MOIST ENVIRONMENT
WHICH IS SUPPORTING THE GENERATION OF SCATTERED MODERATE
CONVECTION AND TSTMS FROM 13N TO INLAND CUBA BETWEEN 74W-87W.
UPPER-LEVEL WINDS HAVE BECOME MORE FAVORABLE...AND DEVELOPMENT
OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS IT
MOVES NORTHWESTWARD TOWARD THE YUCATAN PENINSULA AND SOUTHERN
GULF OF MEXICO. ENVIRONMENTAL CONDITIONS COULD BE A LITTLE MORE
MARGINAL FOR DEVELOPMENT WHILE THE SYSTEM IS OVER THE GULF OF
MEXICO LATER THIS WEEK. CURRENTLY...THIS SYSTEM HAS A MEDIUM
CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

...TROPICAL WAVES...
A TROPICAL WAVE HAS COME OFF THE WEST AFRICAN COAST WITH AXIS
EXTENDING FROM 18N18W TO 11N16W. THIS WAVE IS ASSOCIATED WITH A
1008 MB LOW EMBEDDED WITHIN THE MONSOON TROUGH AXIS AND IS
PRODUCING SCATTERED MODERATE CONVECTION FROM 08N-15N E OF 25W.
THIS CONVECTION COINCIDES WITH AN AREA OF MAXIMUM MOISTURE IN
TOTAL PRECIPITABLE WATER IMAGERY. UPPER-LEVEL WINDS ARE EXPECTED
TO BE CONDUCIVE FOR SOME DEVELOPMENT OF THIS WAVE DURING THE
NEXT FEW DAYS UNTIL THE WAVE ENTERS A MORE STABLE ENVIRONMENT BY
THIS WEEKEND. CURRENTLY...THIS SYSTEM HAS A LOW CHANCE...10
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS.

A TROPICAL WAVE IS ASSOCIATED WITH A 1010 MB LOW EMBEDDED WITHIN
THE MONSOON TROUGH AXIS. THE WAVE AXIS EXTENDS FROM 19N35W TO
THE LOW NEAR 12N37W AND IS MOVING W NEAR 10 KT. TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED WITHIN A
MODERATE TO HIGH MOIST ENVIRONMENT AT THE LOWER LEVELS.
HOWEVER...METEOSAT SATELLITE IMAGERY SHOW SAHARAN DUST AND DRY
AIR SPREADING OVER THE WAVE ENVIRONMENT N OF 13N WHERE
CONVECTION IS BEING HINDERED. SCATTERED MODERATE CONVECTION IS
CONFINED TO THE MONSOON TROUGH FROM 11N-13N BETWEEN 38W-41W.

A WEAK TROPICAL WAVE EXTENDS FROM 18N63W TO 10N64W MOVING W NEAR
10 KT. THE WAVE IS EMBEDDED IN A LOW TO MODERATE MOIST
ENVIRONMENT AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY.
UPPER LEVEL DIFFLUENCE FROM A RIDGE CENTERED IN THE CARIBBEAN
AND A LOW IN THE ATLC IS ENHANCING ISOLATED RAINSHOWERS ACROSS
THE LEEWARD ISLANDS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
13N16W TO 14N33W 06N47W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 06N47W TO 04N51W. BESIDES THE CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED MODERATE
CONVECTION IS FROM 09N-13N BETWEEN 25W-35W.

...DISCUSSION...

GULF OF MEXICO...
ANTICYCLONIC WIND FLOW IN THE RANGE OF 5-10 KT DOMINATES THE
GULF WATERS N OF 24N ANCHORED BY A 1016 MB HIGH NEAR 27N91W. AN
ELONGATED UPPER LEVEL LOW EXTENDING FROM SOUTHERN FLORIDA TO THE
BAY OF CAMPECHE IS SUPPORTING A SURFACE TROUGH ALONG 23N88W TO
20N90W 17N92W. THIS TROUGHINESS IS ENHANCING SCATTERED MODERATE
CONVECTION AND TSTMS OVER THE YUCATAN PENINSULA WHICH EXTEND
OVER THE BAY OF CAMPECHE S OF 21N E OF 92W. ISOLATED RAINSHOWERS
AND TSTMS ARE ALSO BEING GENERATED FROM 22N-26N BETWEEN 86W-94W.
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 GEORGIA AND LOUISIANA. THIS SCENARIO ALONG WITH
A SURFACE PRE-FRONTAL SURFACE TROUGH IS SUPPORTING LOW LEVEL
CONVERGENCE AND LIFTING OF MOIST AIR WHICH IS ENHANCING NUMEROUS
MODERATE CONVECTION AND TSTMS INLAND. THIS CONVECTION EXTENDS
WITHIN 100 NM OFF THE NORTHERN GULF COAST AS SCATTERED SHOWERS
AND ISOLATED TSTMS BETWEEN 85W-89W. OTHERWISE...FAIR WEATHER IS
OVER THE REMAINDER BASIN SUPPORTED BY DRY AIR IN THE LOWER AND
MIDDLE LEVELS.

THE HIGH PRESSURE IS EXPECTED TO DISSIPATE WEDNESDAY
MORNING...HOWEVER A NEW HIGH IS EXPECTED TO FORM OVER THE NW
GULF IN THE AFTERNOON WHICH WILL PERSIST IN THE NORTHERN GULF
THROUGH THURSDAY NIGHT. THE TROPICAL WAVE OVER THE WESTERN
CARIBBEAN IS EXPECTED TO ENTER THE SE BASIN THURSDAY AFTERNOON.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS
EXTENDING FROM 20N79W TO A 1009 MB LOW NEAR 11N82W. THE WAVE IS
EMBEDDED IN A HIGH MOIST ENVIRONMENT WHICH IS SUPPORTING THE
GENERATION OF SCATTERED MODERATE CONVECTION AND TSTMS FROM 13N
TO INLAND CUBA BETWEEN 74W-87W. CONVECTION ASSOCIATED WITH THE
WAVE EXTENDS ACROSS HISPANIOLA BEING ENHANCED BY UPPER LEVEL
DIVERGENCE FROM A HIGH CENTERED BETWEEN THIS ISLAND AND JAMAICA.
SCATTERED RAINSHOWERS AND TSTMS ARE OVER THE MONA PASSAGE BEING
ENHANCED BY UPPER LEVEL DIFFLUENCE FROM THE RIDGE CENTERED IN
THE CARIBBEAN AND AN ELONGATED LOW IN THE ATLC WITH AXIS NEAR
61W. THIS UPPER LEVEL DIFFLUENCE IS ALSO ENHANCING ISOLATED
RAINSHOWERS ACROSS THE LEEWARD ISLANDS AND NEAR THE VICINITY OF
THE A WEAK TROPICAL WAVE THAT EXTENDS FROM 18N63W TO 10N64W.

UPPER-LEVEL WINDS ARE EXPECTED TO BECOME MORE FAVORABLE FOR
DEVELOPMENT OF THE TROPICAL WAVE IN THE WEST CARIBBEAN OVER THE
NEXT COUPLE OF DAYS WHILE IT MOVES TOWARD THE YUCATAN PENINSULA.
RAINSHOWERS ASSOCIATED WITH THIS TROPICAL WAVE ARE EXPECTED TO
PERSISTS ACROSS THE WESTERN CARIBBEAN WITHIN THE NEXT 48 HOURS.

HISPANIOLA...
SCATTERED MODERATE CONVECTION AND TSTMS ASSOCIATED WITH THE
TROPICAL WAVE IN THE W CARIBBEAN EXTENDS ACROSS HISPANIOLA BEING
ENHANCED BY UPPER LEVEL DIVERGENCE FROM A HIGH CENTERED BETWEEN
THIS ISLAND AND JAMAICA. WEATHER CONDITIONS ARE EXPECTED TO
IMPROVE VERY EARLY ON WEDNESDAY AS THE WAY CONTINUE TO MOVE W-NW
TOWARDS THE YUCATAN PENINSULA. FAIR WEATHER IS EXPECTED TO
CONTINUE THROUGHOUT THE REST OF THE DAY AS A DRY AIRMASS MOVES
INTO THE ISLAND INHIBITING CONVECTION.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW CENTERED NEAR 28N60W IS SUPPORTING A SURFACE
TROUGH ALONG 30N57W TO 24N60W. STRONG DEEP LAYER ENVIRONMENTAL
SHEAR MAINTAINS THE CONVECTION ASSOCIATED WITH THIS TROUGH W OF
IT...SCATTERED MODERATE FROM 23N-29N BETWEEN 60W-68W.
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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