[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 031821 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 03 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
1745 UTC.

...SPECIAL FEATURE...

HURRICANE ARTHUR IS CENTERED NEAR 32.4N 78.5W AS OF 03/1500
UTC...OR ABOUT 95 NM S-SW OF CAPE FEAR NORTH CAROLINA... MOVING
N-NE AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB.
MAXIMUM SUSTAINED WIND SPEED IS 80 KT WITH GUSTS OF 100 KT. A
TURN TOWARD THE NORTHEAST WITH AN INCREASE IN FORWARD SPEED IS
EXPECTED TODAY...FOLLOWED BY A FURTHER INCREASE IN FORWARD SPEED
TONIGHT AND FRIDAY. REGARDING FORECAST TRACK...THE CORE OF
ARTHUR IS EXPECTED TO APPROACH THE COAST IN THE HURRICANE
WARNING AREA TONIGHT. NUMEROUS MODERATE/ISOLATED STRONG
CONVECTION IS FROM 31N-35N BETWEEN 75W-80W WITH LIGHTING DATA
SHOWING TSTMS IN THE E SEMICIRCLE OF THIS CONVECTION. ARTHUR
RAINBANDS ARE GENERATING SHOWERS AND TSTMS OVER THE NORTHERN
BAHAMAS AND N OF 26N BETWEEN 72W-77W. PLEASE SEE THE LATEST
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE HAS COME OFF THE WEST AFRICAN COAST EARLIER THIS
MORNING. THE WAVE AXIS EXTENDS FROM 16N17W TO 7N18W AND IS
EXPECTED TO MOVE NEAR 15 KT DURING THE NEXT 24 HOURS. THE WAVE
IS BEING ENGULFED BY THE SAHARAN AIR LAYER DRY AIR WHILE
METEOSAT PSEUDO NATURAL COLOR IMAGERY SHOW DUST ASSOCIATED WITH
THIS AIRMASS IN THE WAVE ENVIRONMENT. THERE IS NO CONVECTION
ASSOCIATED WITH THIS WAVE.

TROPICAL WAVE IS LOCATED OVER THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 22N43W TO 11N44W...MOVING W AT 20 KT. THERE IS NO
CONVECTION ASSOCIATED WITH THE WAVE AS IT IS EMBEDDED IN THE
DRY AND DUSTY SAHARAN AIR LAYER.

TROPICAL WAVE IS LOCATED OVER THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 19N63W TO 11N69W...MOVING W AT 20 KT. LOW-LEVEL
LOW TO MODERATE MOIST AIR ACCOMPANIES THIS WAVE. THIS FACTOR
ALONG WITH DRY AIR SUBSIDENCE FROM ALOFT AND STRONG DEEP LAYER
ENVIRONMENTAL SHEAR ACROSS THE CARIBBEAN ARE INHIBITING THE
DEVELOPMENT OF DEEP CONVECTION. SCATTERED SHOWERS ARE ACROSS
WESTERN PUERTO RICO WITH ISOLATED SHOWERS EXTENDING TO ADJACENT
WATERS.

TROPICAL WAVE IS LOCATED OVER THE FAR NW CARIBBEAN WITH AXIS
EXTENDING FROM 20N85W TO 13N87W...MOVING W AT 20-25 KT. DEEP
LAYER MOISTURE AND LOW ENVIRONMENTAL SHEAR ARE SUPPORTING
SCATTERED SHOWERS AND TSTMS AHEAD OF THE WAVE AXIS...INCLUDING
NICARAGUA...HONDURAS...BELIZE AND THE EASTERN YUCATAN PENINSULA.

TROPICAL WAVE IS LOCATED OVER THE BAY OF CAMPECHE WITH AXIS
EXTENDING FROM 22N94W TO 14N95W...MOVING W AT 20-25 KT DURING
THE PAST 24 HOURS. AN UPPER LEVEL LOW AND MOISTURE IN THE SW
GULF SUPPORT SCATTERED SHOWERS AND TSTMS S OF 25N W OF 92W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 9N13W
TO 7N20W TO 7N28W. THE ITCZ BEGINS NEAR 7N28W AND CONTINUES TO A
1015 MB LOW NEAR 8N36W...THEN ALONG 6N49W TO 6N57W. SCATTERED
SHOWERS ARE FROM 4N-6N BETWEEN 20W-28W.

...DISCUSSION...

...THE GULF OF MEXICO...

AN ELONGATED UPPER LEVEL CYCLONIC CIRCULATION IS OVER THE
WESTERN GULF SUPPORTING A TROPICAL WAVE MOVING ACROSS THE BAY OF
CAMPECHE AS WELL AS SHOWERS AND TSTMS IN THE SW GULF. SEE
TROPICAL WAVES SECTION FOR MORE INFORMATION ON THE WAVE.
MOISTURE ADVECTED TO THE EASTERN BASIN BY NOW HURRICANE ARTHUR
ALONG WITH A MID-LEVEL DIVERGENT ENVIRONMENT SUPPORT HEAVY
SHOWERS AND TSTMS FROM 25N-29N BETWEEN 84W-91W. A TROPICAL WAVE
OVER THE FAR NW CARIBBEAN IS GENERATING SHOWERS AND TSTMS OVER
WESTERN CUBA AND THE YUCATAN CHANNEL. A WEAK HIGH PRESSURE
CENTER OF 1018 MB IS OVER THE NW GULF CENTERED NEAR 27N95W. WITH
NO SUPPORT IN THE MID-UPPER LEVELS...THIS HIGH IS EXPECTED TO
DISSIPATE DURING THE NEXT 24 HOURS. OTHERWISE...VARIABLE WINDS
OF 5-10 KT ARE ACROSS THE GULF WATERS. A FRONTAL BOUNDARY IS
EXPECTED TO LINGER ALONG THE NORTHERN GULF COASTLINE THROUGH
SUNDAY...THUS INCREASING THE CHANCES OF RAIN IN THIS ZONE AND
ADJACENT WATERS.

...THE CARIBBEAN SEA...

TWO TROPICAL WAVES ARE MOVING ACROSS THE CARIBBEAN WATERS. ONE
OF THE WAVES IS OVER THE FAR NW BASIN GENERATING SHOWERS AND
TSTMS W OF OF 81W...INCLUDING WESTERN CUBA...THE E YUCATAN
PENINSULA...THE YUCATAN CHANNEL...BELIZE AND HONDURAS. A SECOND
WAVE IS OVER THE EASTERN CARIBBEAN. LOW-LEVEL LOW TO MODERATE
MOIST AIR ACCOMPANIES THIS WAVE. THIS FACTOR ALONG WITH DRY AIR
SUBSIDENCE FROM ALOFT AND STRONG DEEP LAYER ENVIRONMENTAL SHEAR
ACROSS THE CARIBBEAN ARE INHIBITING THE DEVELOPMENT OF DEEP
CONVECTION. SCATTERED SHOWERS ARE ACROSS WESTERN PUERTO RICO
WITH ISOLATED SHOWERS EXTENDING TO ADJACENT WATERS. THIS WAVE IS
ALSO ENHANCING SHOWERS AND ISOLATED TSTMS OVER THE MONA PASSAGE
AND SOUTHERN DOMINICAN REPUBLIC. SEE TROPICAL WAVES SECTION
ABOVE FOR MORE DETAILS. OVER THE SW BASIN...THE MONSOON TROUGH
IS ENHANCING HEAVY SHOWERS AND TSTMS S OF 12N W OF 80W. BROAD
HIGH PRESSURE OVER THE ATLC EXTENDS A RIDGE TO THE NORTHERN
CARIBBEAN...THUS TIGHTENING THE PRESSURE GRADIENT AND SUPPORTING
EASTERLIES OF 20-25 KT S OF 17N BETWEEN 64W-83W WITH NEAR GALE
FORCE WINDS ALONG THE COAST OF COLOMBIA. THE NEXT TROPICAL WAVE
WILL ENTER THE EASTERN BASIN BY FRIDAY NIGHT.

...HISPANIOLA...

MOSTLY DRY AIR IS ACROSS THE ISLAND WHICH ALONG STRONG WIND
SHEAR VALUES IN THE REGION ARE SUPPRESSING THE DEVELOPMENT OF
DEEP CONVECTION. HOWEVER...A TROPICAL WAVE TO MOVE ACROSS PUERTO
RICO THIS AFTERNOON IS PUSHING SOME MOISTURE WESTWARD THAT IS
ENHANCING ISOLATED SHOWERS AND TSTMS ALONG SOUTHERN DOMINICAN
REPUBLIC AND ADJACENT WATERS AS WELL AS THE MONA PASSAGE.
RAINSHOWERS ACTIVITY WILL INCREASE AS THIS WAVE CONTINUES TO
MOVE WESTWARD TOWARDS THE CENTRAL CARIBBEAN.

...THE ATLANTIC OCEAN...

SCATTERED SHOWERS AND TSTMS ARE OVER THE SW N ATLC ASSOCIATED
WITH THE RAINBANDS OF HURRICANE ARTHUR NOW N OF THE AREA OF
DISCUSSION. SEE THE SPECIAL FEATURES SECTION ABOVE FOR MORE
INFORMATION ON ARTHUR. FARTHER EAST...A SURFACE TROUGH IS
ANALYZED FROM 30N65N TO 26N64W WHICH IS GENERATING ISOLATED
SHOWERS WITHIN 100 NM EITHER SIDE OF IT N OF 28N AND SCATTERED
MODERATE CONVECTION FROM 25N-28N BETWEEN 63W-66W. REMNANT
SCATTERED SHOWERS ASSOCIATED WITH A FORMER FRONTAL BOUNDARY ARE
N OF 27N BETWEEN 52W-56W. OTHERWISE...BESIDES THE TROPICAL WAVES
DISCUSSED ABOVE...HIGH SURFACE PRESSURE AND RIDGING DOMINATE
ELSEWHERE.

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

$$
NR


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