[Tropical] Tropical Weather Discussion

[EMWIN Server]

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




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