[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181735
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU SEP 18 2014

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
1730 UTC.

...SPECIAL FEATURES...

AS OF 18/1500 UTC...HURRICANE EDOUARD IS CENTERED NEAR 39.9N
42.7W MOVING E AT 22 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
970 MB. MAXIMUM SUSTAINED WINDS ARE 70 KT WITH GUSTS TO 85 KT.
EDOUARD IS EXPECTED TO DECREASE IN FORWARD SPEED TODAY
...FOLLOWED BY A SLOWER EASTWARD MOTION FRIDAY AND FRIDAY NIGHT.
SCATTERED MODERATE CONVECTION IS FROM 37N-43N BETWEEN 41W-46W.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OFF THE WESTERN COAST OF AFRICA WITH AXIS
EXTENDING FROM 18N17W TO A 1009 MB LOW NEAR 11N18W. METEOSAT SAL
IMAGERY SHOW BOTH DUST AND DRY AIR IN THE ENVIRONMENT OF THE
WAVE...MAINLY TO THE NW OF IT WHICH IS LIMITING CONVECTION TO
THE AREA NEAR THE LOW AND THE MONSOON TROUGH. SCATTERED MODERATE
CONVECTION IS OBSERVED FROM 06N-13N E OF 22W.

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLANTIC WITH AXIS
EXTENDING FROM 19N42W TO A 1012 MB LOW NEAR 15N43W TO
11N44W...MOVING WEST AT 15-20 KT. DEEP LAYER WIND SHEAR IS
NOTICED IN THE ENVIRONMENT OF THIS WAVE WHICH IS LIMITING
CONVECTION TO JUST ISOLATED SHOWERS FROM 16N-20N BETWEEN 37W-43W.

A TROPICAL WAVE IS S OF THE PUERTO RICO TRENCH WITH AXIS
EXTENDING FROM 20N64W TO 11N64W...MOVING WEST AT 15 KT. THIS
WAVE IS ENHANCED AT UPPER LEVELS BY A LOW CENTERED NEAR 25N65W.
SCATTERED MODERATE CONVECTION ALONG THIS WAVE AXIS BETWEEN 60W-
65W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
A 1009 MB LOW NEAR 11N18W TO 14N35W. THE ITCZ AXIS BEGINS W OF A
TROPICAL WAVE NEAR 11N47W AND CONTINUES TO 08N60W. OTHER THAN
THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ALREADY
DISCUSSED...SCATTERED MODERATE CONVECTION IS FROM 6N-11N BETWEEN
45W-50W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL TROUGH EXTENDS FROM THE EASTERN U.S. TO THE WEST
ATLC NEAR 60W WITH BASE EXTENDING ACROSS FLORIDA AND THE SW N
ATLC. TO THE W OF THIS TROUGH...AN UPPER-LEVEL HIGH IS CENTERED
OVER NW MEXICO NEAR 25N106W. WITH THESE FEATURES...UPPER-LEVEL
NORTHERLY FLOW PREVAILS ACROSS THE BASIN. AT LOW LEVELS...A
SURFACE HIGH IS LOCATED NEAR 27N90W. A SURFACE TROUGH EXTENDS
FROM THE ATLC ACROSS SOUTH FLORIDA TO THE WESTERN GULF WATERS.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS PRESENT FROM
24N-29N W OF 92W. ELSEWHERE ACROSS THE BASIN...NO CONVECTION IS
NOTICED. FOR THE NEXT 48 HOURS...A FRONTAL TROUGH CURRENTLY
LOCATED ACROSS NORTH FLORIDA WILL MOVE S ACROSS THE PENINSULA
WHILE THE PORTION OF THE TROUGH OVER GULF WATERS WILL STALL
ACROSS THE NORTHERN TO CENTRAL GULF. THE FRONTAL SYSTEM WILL
BECOME STATIONARY ACROSS THE CENTRAL AND SE GULF ON FRIDAY.

CARIBBEAN SEA...

AN UPPER-LEVEL HIGH IS CENTERED ACROSS THE COASTAL WATERS OF W
VENEZUELA NEAR 11N68W. THIS SYSTEM PAIRED WITH AN UPPER-LEVEL
LOW ACROSS THE ATLC N OF PUERTO RICO NEAR 25N65W ARE KEEPING A
DIFFLUENT FLOW NEAR THE TROPICAL WAVE OVER THE VIRGIN ISLANDS.
THERE IS ALSO AN UPPER-LEVEL LOW CENTERED OVER THE COASTAL
WATERS OF HONDURAS NEAR 17N83W. A DIFFLUENT FLOW IS ALSO NOTICED
ACROSS THE WATERS N OF PANAMA NEAR THE MONSOON TROUGH WHICH IS
ENHANCING SCATTERED MODERATE CONVECTION S OF 13N. DEEP LAYER
ENVIRONMENTAL SHEAR INHIBITS CONVECTION ELSEWHERE. OTHERWISE...A
RELAXED PRESSURE GRADIENT CONTINUE TO SUPPORT TRADES OF 10-15 KT
ACROSS THE BASIN. OVER THE NEXT 48 HOURS...THE TROPICAL WAVE IS
FORECAST TO MOVE ACROSS HISPANIOLA ON FRIDAY AND ACROSS CUBA BY
SATURDAY.

...HISPANIOLA...

NO CONVECTION IS PRESENT ACROSS THE ISLAND. DIURNAL SHOWER
ACTIVITY IS FORECAST TO DEVELOP IN THE AFTERNOON AND WILL
GRADUALLY INCREASE BY FRIDAY AS THE TROPICAL WAVE APPROACHES.

ATLANTIC OCEAN...

UPPER LEVEL HIGH PREVAILS ACROSS THE EASTERN ATLC E OF 55W.
STRONG DEEP LAYER WIND SHEAR IS ALSO PRESENT ACROSS THAT AREA
INHIBITING CONVECTION. AN UPPER-LEVEL LOW IS CENTERED OVER
WATERS N OF PUERTO RICO NEAR 25N65W. AT LOW LEVELS...SCATTERED
MODERATE TO STRONG CONVECTION IS PRESENT NEAR THE UPPER-LOW N OR
PUERTO RICO AND ALONG A SURFACE TROUGH FROM 20N-29N BETWEEN 58W-
65W. ANOTHER SURFACE TROUGH EXTENDS FROM THE ATLC ACROSS SOUTH
FLORIDA TO THE WESTERN GULF WATERS GENERATING SCATTERED MODERATE
CONVECTION FROM 24N-30N BETWEEN 67W-80W. FOR CONVECTION RELATED
TO THE TROPICAL WAVES...PLEASE REFER TO THE SECTION ABOVE.

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

$$
ERA


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