[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 19 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...TROPICAL WAVES...

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
ANALYZED FROM 19N40W TO THE MONSOON TROUGH AXIS NEAR 11N38W.
WAVE IS MOVING W AT ABOUT 15-20 KT. LOW TO MID LEVEL MOISTURE
COVERS A GREAT AREA OF THE WAVE S OF 15N. HOWEVER...A LAYER OF
DRY/SAHARAN AIR CONTINUES TO OVERTAKE THE WAVE LIMITING THE
CONVECTIVE ACTIVITY AROUND THE WAVE AXIS.

TROPICAL WAVE MOVES WEST OF THE LESSER ANTILLES WITH AXIS
EXTENDING FROM 20N67W TO 12N62W MOVING W AT 15-20 KT. THE WAVE
PRECEDES A NARROW SURGE OF MOISTURE NOTED ON TOTAL PRECIPITABLE
WATER IMAGERY. WAVE IS INTERACTING WITH AN UPPER LEVEL LOW
MOVING CENTERED OVER THE WINDWARD PASSAGE NEAR 19N75W. CLUSTERS
OF MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS N OF 13N E OF THE
MONA PASSAGE.

TROPICAL WAVE MOVES ACROSS THE BAY OF CAMPECHE WITH AXIS
EXTENDING FROM 22N91W TO INLAND OVER WRN GUATEMALA NEAR 15N91W
MOVING W AT ABOUT 10 KT. SCATTERED SHOWERS AND THUNDERSTORMS ARE
ACROSS MOST OF THE BAY S OF 22N. THE ACTIVITY IS ENHANCED BY A
WEAK UPPER LOW CENTERED NEAR 20N91W. THE WAVE WILL CONTINUE TO
TRACK WESTWARD WITH SCATTERED THUNDERSTORM ACTIVITY AFFECTING
MAINLY THE COASTAL WATERS NEAR VERACRUZ AND TAMPICO OVER THE
NEXT 24 HOURS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INLAND ACROSS WEST AFRICA...ENTERING
THE ATLC THROUGH THE COAST OF GUINEA NEAR 10N14W TO 8N22W 12N35W
TO 8N46W...WHERE THE ITCZ CONTINUES WEST TO THE COAST OF GUYANA
NEAR 8N59W. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS
FROM 7N-13N BETWEEN 35W-40W AND WITHIN 130 NM S OF THE MONSOON
TROUGH E OF 30W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL CYCLONIC CIRCULATION CENTERED OVER ERN GEORGIA
CONTINUES TO DOMINATE THE WEATHER ACROSS THE NE AND N-CENTRAL
GULF WATERS THIS AFTERNOON. MID TO UPPER LEVEL LIFT ASSOCIATED
TO IT IS HELPING TO MAINTAIN CLUSTERS OF SCATTERED SHOWERS AND
THUNDERSTORMS N OF 26N E OF 91W. A BROAD UPPER LEVEL LOW
CONTINUES TO DRIFT W ACROSS NRN SIERRA MADRE MOUNTAINS WITH LESS
INFLUENCE IN THE SHOWER ACTIVITY OVER THE WRN GULF WATERS
COMPARED TO 24 HOURS AGO. JUST A FEW ISOLATED SHOWERS ARE
DEPICTED ON RADAR IMAGERY W OF 94W N OF VERACRUZ MEXICO. A
TROPICAL WAVE MOVES ACROSS THE BAY OF CAMPECHE GENERATING
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE BAY IN
COLLABORATION WITH A WEAK UPPER LOW CENTERED NEAR 20N91W. FAIR
WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE AREA THIS AFTERNOON.
AS THE UPPER LOW OVER THE SE CONUS REMAINS NEARLY STATIONARY...
SHORT RANGE COMPUTER MODELS SUGGEST THE RAIN ACTIVITY OVER THE
NE AND N-CENTRAL GULF WILL REMAIN IN PLACE DURING THE NEXT 24
HOURS. THE TROPICAL WAVE WILL CONTINUE TO TRACK WESTWARD WITH
SCATTERED THUNDERSTORM ACTIVITY AFFECTING MAINLY THE COASTAL
WATERS NEAR VERACRUZ AND TAMPICO DURING THE FORECAST PERIOD.

CARIBBEAN SEA...
THE MAIN AREA OF ACTIVE WEATHER IS FOUND OVER THE ERN CARIBBEAN
BASIN...AS A TROPICAL WAVE MOVES W OF THE LESSER ANTILLES WITH
SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS N OF 13N E
OF THE MONA PASSAGE. DOPPLER RADAR IMAGERY INDICATES THE OVERALL
ACTIVITY IS MOVING WESTWARD AT ABOUT 15-20 KT AND IS EXPECTED TO
REACH THE WATERS S OF HISPANIOLA LATER THIS EVENING. THE WAVE IS
INTERACTING WITH AN UPPER LEVEL LOW MOVING WEST ACROSS THE
WINDWARD PASSAGE. SIMILAR ACTIVITY IS FOUND OVER THE SOUTH WEST
CARIBBEAN...WITHIN 90 NM OFF THE COAST OF WRN PANAMA AND COSTA
RICA...ASSOCIATED TO THE MONSOON TROUGH AXIS EXTENDING ACROSS
NRN COLOMBIA TO THE SRN COASTAL WATERS OF PANAMA AND WRN COSTA
RICA. THE REMAINDER OF THE DISCUSSION AREA IS UNDER FAIR WEATHER
WITH A FEW ISOLATED FAST MOVING SHOWERS EMBEDDED IN THE MODERATE
TO FRESH EASTERLY TRADE WINDS. WATER VAPOR IMAGERY SHOWS DRY AIR
ALOFT COVERING A GREAT PORTION OF THE DISCUSSION AREA WITH
SAHARAN DUST NOTED ON MOST UPPER AIR SOUNDINGS AND VISIBLE
IMAGERY DATA.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY MOVING WEST
ACROSS THE WINDWARD PASSAGE. AN UPPER INVERTED TROUGH EXTENDS NW
FROM THE LOW CENTER TO NEAR 32N60W. THIS FEATURE IS CURRENTLY
NOT HAVING ANY SIGNIFICANT IMPACTS AT SURFACE. OTHERWISE...A
LARGE AREA OF HIGH PRESSURE DOMINATES THE REMAINDER OF THE ATLC
DISCUSSION AREA ANCHORED BY A 1030 MB HIGH CENTERED NEAR 33N34W.
THE FAIR WEATHER IN THIS REGION IS FURTHER ENHANCED BY A BROAD
LAYER SAHARAN DUST ALOFT NOTED ON METEOSAT-9. WITH SAHARAN DUST
ALOFT PRESENT ACROSS THE AREA AND STRONG SURFACE RIDGING
EXTENDING WESTWARD...LITTLE CHANGE IS EXPECTED ACROSS THE
DISCUSSION AREA FOR AT LEAST THE NEXT 24 HOURS.

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

$$

GARCIA




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