[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE JUL 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1022 UTC.

...SPECIAL FEATURES...
A TROPICAL WAVE ASSOCIATED WITH A 1010 MB SURFACE LOW HAS ITS
AXIS JUST E OF THE CAPE VERDE ISLANDS EXTENDING FROM 15N22W TO
07N23W AND MOVING W NEAR 5 KT. THIS SYSTEM IS EMBEDDED IN A HIGH
MOIST ENVIRONMENT AT THE LOWER AND MIDDLE LEVELS WHICH COMBINED
WITH UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE
CONVECTION FROM 09N-13N BETWEEN 21W-27W. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO BECOME MORE FAVORABLE FOR TROPICAL
CYCLONE DEVELOPMENT. CURRENTLY...THERE IS A MEDIUM CHANCE FOR
THIS SYSTEM TO BECOME A TROPICAL CYCLONE DURING THE NEXT 48
HOURS.

...TROPICAL WAVES...
A TROPICAL WAVE IS MOVING ACROSS THE DOMINICAN REPUBLIC WITH A
TILTED AXIS EXTENDING ALONG 21N67W TO 15N72W AND MOVING NEAR 15
KT. THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT AND AT
THE MOMENT ONLY ISOLATED SHOWERS AND TSTMS ARE WITHIN 80 NM
EITHER SIDE OF THE WAVE AXIS N OF 19N. HOWEVER...MIDDLE LEVEL
DIFFLUENT FLOW MAY ASSIST IN DEVELOPING CONVECTION AS THE WAVE
CONTINUE A W-NW TRACK ACROSS THE HISPANIOLA TODAY.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 15N16W AND CONTINUES TO 14N20W. THE ITCZ AXIS
EXTENDS W OF A TROPICAL WAVE NEAR 11N26W TO 06N39W 05N52W.
BESIDES THE CONVECTION ALREADY DISCUSSED ASSOCIATED WITH THE
TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 07N-12N E
OF 18W. ISOLATED RAINSHOWERS ARE WITHIN 100 NM S OF THE ITCZ
AXIS BETWEEN 33W-38W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING DOMINATES THE GULF ANCHORED BY A 1020 MB HIGH
NEAR 27N86W THAT IS PROVIDING RETURN FLOW IN THE RANGE OF 5-15
KT. EXCEPT FOR THE NE GULF N OF 28N...VERY DRY AIR AT THE LOWER
AND MIDDLE LEVELS ACROSS THE BASIN IS SUPPORTING FAIR WEATHER.
OVER THE NE GULF...A HIGH MOIST ENVIRONMENT AT THE LOWER AND
MIDDLE LEVELS AS WELL AS UPPER LEVEL DIFFLUENCE ARE SUPPORTING A
CLUSTER OF MODERATE CONVECTION N OF 28N E OF 86W.

THE HIGH IS EXPECTED TO PERSIST OVER THE GULF WATERS WITHIN THE
NEXT 48 HOURS. RAINSHOWERS OVER THE NE GULF ARE EXPECTED TO
CONTINUE UNTIL VERY LATE ON TUESDAY BUT THE REST OF THE BASIN
WILL ENJOY FAIR WEATHER AS DRY AIR CONTINUES TO BE ADVECTED FROM
THE CARIBBEAN INTO THE GULF.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS MOVING ACROSS THE DOMINICAN REPUBLIC THIS
MORNING GENERATING ISOLATED SHOWERS/TSTMS AND ADVECTING MODERATE
MOISTURE ACROSS THE HISPANIOLA. RAINSHOWERS MAY DEVELOPED OVER
THE ISLAND AS THE DAY PROGRESSES ASSISTED BY MIDDLE LEVEL
DIFFLUENT FLOW. A VERY MOIST ENVIRONMENT IN THE LOWER AND MIDDLE
LEVELS IS OVER THE SOUTHERN CARIBBEAN S OF 17N W OF 78W. THIS
MOIST ENVIRONMENT COMBINED WITH UPPER LEVEL DIFFLUENCE IS
SUPPORTING SCATTERED MODERATE CONVECTION WITH ISOLATED TSTMS
OVER NICARAGUA AND WITHIN 190 NM OFF ITS COASTLINE AS WELL AS
WITHIN 110 NM OFF THE COAST OF HONDURAS. SIMILAR CONVECTION IS S
OF 10N INCLUDING PANAMA AND THE COASTAL WATERS OF COSTA RICA
BEING ASSOCIATED WITH THE MONSOON TROUGH AXIS. ISOLATED
RAINSHOWERS ARE WITHIN 100 NM OF THE SOUTHERN COAST OF CUBA
BETWEEN 79W-82W. OVER THE REMAINDER BASIN...DRY AIR IN THE LOWER
AND MIDDLE LEVELS IS SUPPORTING FAIR WEATHER.
OTHERWISE...TRADEWINDS UP TO 25 KT PREVAIL OVER THE CENTRAL-
SOUTHERN CARIBBEAN WITH LIGHTER WINDS UP TO 15 KT ELSEWHERE.

THE TROPICAL WAVE WILL MOVE OFF THE COAST OF HAITI THIS
AFTERNOON AND MOVE TO EASTERN CUBA WHERE INTERACTION WITH THE
TERRAIN AND VERY DRY AIR MAY ACT TO VANISH THIS WAVE.

HISPANIOLA...
A TROPICAL WAVE IS MOVING ACROSS THE DOMINICAN REPUBLIC THIS
MORNING WITH AXIS EXTENDING FROM 21N67W TO 15N72W. THE WAVE IS
GENERATING ISOLATED SHOWERS AND IS ADVECTING MODERATE MOISTURE
ACROSS THE ISLAND. RAINSHOWERS MAY DEVELOPED OVER THE ISLAND AS
THE DAY PROGRESSES ASSISTED BY MIDDLE LEVEL DIFFLUENCE. WEATHER
IMPROVES THIS AFTERNOON FOR THE DOMINICAN REPUBLIC AS A MASS OF
DRY AIR ENTERS THIS PORTION OF THE ISLAND. THE DRY AIR MASS WILL
CONTINUE TO MOVE WESTWARD AND WILL MOVE OFF THE COAST OF HAITI
VERY EARLY ON WEDNESDAY. AFTERNOON/EARLY EVENING SHOWERS ARE
EXPECTED ON WEDNESDAY SUPPORTED BY A FAVORABLE UPPER LEVEL
PATTERN.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 30N51W IS SUPPORTING
SCATTERED SHOWERS AND ISOLATED TSTMS N OF 26N BETWEEN 49W-59W. A
SURFACE TROUGH EXTENDS FROM A 1018 MB LOW NEAR 30N32W TO 27N36W
26N41W...NO CONVECTION IS ASSOCIATED WITH IT AT THE TIME.
OTHERWISE...SURFACE RIDGING IS ACROSS THE REMAINDER BASIN
ANCHORED BY A 1022 MB HIGH NEAR 36N43W. BESIDES THE AREAS
FORMERLY DISCUSSED...FAIR WEATHER IS ACROSS THE REMAINDER ATLC
SUPPORTED BY DRY AIR AT THE LOWER AND MIDDLE LEVELS.

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

$$
RAMOS

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