000
AXNT20 KNHC 161804
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON JUL 16 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...

COMPUTER MODEL DATA AND SURFACE OBSERVATIONS ACROSS FAR WEST 
AFRICA SUGGESTED A TROPICAL WAVE MOVING OFF THE COAST OF 
MAURITANIA AND SENEGAL EARLY THIS MORNING WITH AXIS ANALYZED 
FROM 18N16W TO 11N17W. NO CONVECTION IS CURRENTLY ASSOCIATED TO 
THE WAVE DUE TO HIGH REFLECTIVITY VALUES DRY/SAHARAN AIR NOTED 
ON METEOSAT-9. THEREFORE...AS THE WAVE CONTINUES EMBEDDED IN 
THIS ENVIRONMENT...THE PLACEMENT OF THE AXIS MAY VARY OVER THE 
NEXT FEW DAYS. 

TROPICAL WAVE MOVES ACROSS THE TROPICAL CENTRAL ATLC EXTENDING  
FROM 19N42W TO 10N45W MOVING W AT 15-20 KT. THE WAVE PRECEDES A 
SURGE OF MOISTURE NOTED ON TOTAL PRECIPITABLE WATER IMAGERY WITH 
LIMITED SHOWER ACTIVITY DUE TO SAHARAN DUST AROUND THE AREA. 

TROPICAL WAVE MOVES ACROSS THE N-CENTRAL CARIBBEAN AND SW 
BAHAMAS WITH AXIS EXTENDING FROM 23N73W TO 15N75W MOVING W AT 
15-20 KT. THE WAVE IS EMBEDDED WITHIN A NARROW AREA OF DEEP 
MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE 
IS CURRENTLY UNDERGOING AN AREA OF SAHARAN DUST ALOFT NOTED ON 
METEOSAT-9. THEREFORE...NO SIGNIFICANT CONVECTION IS NOTED ON 
SATELLITE IMAGERY THIS AFTERNOON.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INLAND ACROSS WEST AFRICA...PASSING 
THROUGH COASTAL GUINEA-BISSAU ALONG 12N16W TO 8N25W 10N40W 9N47W 
...WHERE THE ITCZ CONTINUES ALONG 7N53W TO THE COAST OF GUYANA 
NEAR 8N58W. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS 
WITHIN 80 NM ON EITHER SIDE OF THE MONSOON TROUGH/ITCZ AXIS W OF 
27W. SIMILAR CONVECTION IS FROM 6N-11N E OF 20W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL TROUGHING COVERS MOST OF THE GULF BASIN THIS 
AFTERNOON INFLUENCED BY AN UPPER LEVEL LOW OFF THE COAST OF 
GEORGIA AND A WEAKER CYCLONIC CIRCULATION OVER THE SE GULF NEAR 
23N85W. THESE UPPER LEVEL FEATURES SUPPORT A SURFACE TROUGH AXIS 
ANALYZED FROM 29N83W ALONG 25N89W TO 19N93W. DESPITE THE LONG 
EXTENSION OF THIS TROUGH AXIS...MOST OF THE SIGNIFICANT MIDDLE 
TO UPPER LEVEL LIFT ASSOCIATED WITH THE ENVIRONMENT ALOFT IS 
OVER THE NE QUADRANT OF THE BASIN SCATTERED SHOWERS AND TSTMS 
OCCURRING WITHIN 90 NM ON EITHER SIDE OF THE TROUGH AXIS N OF 
24N E OF 88W. THE REMAINDER OF THE GULF IS CURRENTLY UNDER FAIR 
WEATHER CONDITIONS WITH ISOLATED SHOWERS DOTTED ACROSS THE AREA. 
THE SURFACE TROUGH IS FORECAST TO WEAKEN DURING THE NEXT 24 
HOURS WITH LESS SHOWER ACTIVITY REMAINING OVER THE FAR EAST 
BASIN DURING THE FORECAST PERIOD.

CARIBBEAN SEA...
THE BROAD CIRCULATION AROUND AN UPPER LEVEL LOW CENTERED OVER THE
SE GULF OF MEXICO NEAR 23N85W IS HELPING TO GENERATE A FEW 
SHOWERS AND THUNDERSTORMS OVER THE FAR NW CARIBBEAN BASIN W OF 
84W. A TROPICAL WAVE MOVES ACROSS THE N-CENTRAL BASIN ALONG THE 
WINDWARD PASSAGE. THE WAVE IS CURRENTLY UNDERGOING AN AREA OF 
SAHARAN DUST ALOFT NOTED ON METEOSAT-9. HOWEVER...SCATTERED 
SHOWERS AND THUNDERSTORMS ARE DEVELOPING N OF 14N BETWEEN 
69W-73W...WHERE LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH 
MAXIMIZED UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL RIDGE 
CENTERED NEAR 12N80W AND A UPPER TROUGH BASE OVER THE ERN 
CARIBBEAN IS NOTED ON WATER VAPOR IMAGERY. THE REMAINDER OF THE 
DISCUSSION AREA IS UNDER FAIR WEATHER THIS AFTERNOON.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS CENTERED OFF THE COAST OF GEORGIA NEAR 
31N81W GENERATING SCATTERED SHOWERS AND THUNDERSTORMS N OF 23N W 
OF 75W INCLUDING THE NW BAHAMAS. WEAK RIDGING ALOFT IS TO THE 
EAST OF THE UPPER LOW SUPPORTING A 1022 MB HIGH NEAR 28N67W. A 
BROAD UPPER TROUGH EXTENDS SW FROM THE N-CENTRAL ATLC WITH AXIS 
BECOMING NARROW AS IT ENTERS DISCUSSION AREA ALONG 32N51W TO 
OVER THE ERN CARIBBEAN NEAR 17N62W. THIS UPPER LEVEL FEATURE 
SUPPORTS A SMALL AREA OF SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM 
N OF THE AREA TO OUR REGION ALONG 32N53W TO 27N55W. OTHERWISE... 
A LARGE AREA OF HIGH PRESSURE DOMINATES THE REMAINDER OF THE 
ATLC DISCUSSION AREA ANCHORED BY A 1030 MB HIGH CENTERED E OF 
THE IBERIAN PENINSULA NEAR 43N15W. THE WEATHER IN THIS REGION 
IS FURTHER ENHANCED BY A LAYER SAHARAN DUST ALOFT NOTED ON 
METEOSAT-9 E OF 50W.

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

$$

GARCIA