[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091819
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUNE 09 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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...
TROPICAL STORM ARLENE CENTER NEAR 19.8N 84.2W AT 09/1800 UTC
MOVING NORTH 7 KT. MAXIMUM SUSTAINED WIND SPEED 35 KT GUSTS
45 KT. MINIMUM CENTRAL PRESSURE 1002 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS. SATELLITE IMAGES SUGGEST THAT ARLENE IS
SOMEWHAT SHEARED WITH THE CENTER OF CIRCULATION LOCATED TO THE
SOUTHWEST OF A RATHER STRONG CURVED CONVECTIVE BAND...WHERE MOST
OF THE STRONGEST WINDS ARE OCCURRING. THE OVERALL PATTERN HAS
IMPROVED SINCE YESTERDAY. ANOTHER RECONNAISSANCE PLANE WILL BE
IN THE AREA LATER TODAY. THE SHEAR MAY RELAX A LITTLE BIT DURING
THE NEXT COUPLE OF DAYS AS THE UPPER-LEVEL TROUGH OVER THE GULF
OF MEXICO WEAKENS. THIS COULD ALLOW ARLENE TO STRENGTHEN SOME
BEFORE REACHING THE U.S.A. NORTHERN GULF OF MEXICO COAST...
ACCORDING TO THE FORECAST FOR THE NEXT TWO TO THREE DAYS.
A MIDDLE LEVEL RIDGE IS FORECAST TO STRENGTHEN GRADUALLY IN THE
WESTERN ATLANTIC OCEAN...WHICH SHOULD LEAD TO A STEADY INCREASE
IN FORWARD SPEED AND MAYBE A TURN MORE TO THE NORTH-NORTHWEST IN
THE GULF MEXICO. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM
18N TO 21N BETWEEN 79W AND 82W. OTHER MODERATE TO STRONG SHOWERS
AND THUNDERSTORMS ARE FOUND ELSEWHERE IN THE CARIBBEAN SEA FROM
14N TO 22N BETWEEN 78W AND 83W...FROM JUST EAST OF NICARAGUA TO
THE WATERS OF THE CARIBBEAN SEA COAST OF CUBA. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND SHOWERS AND THUNDERSTORMS ARE SPREADING
ACROSS CUBA ELSEWHERE... COVERING AND/OR REACHING SECTIONS OF
THE NORTHWESTERN BAHAMAS...THE STRAITS OF FLORIDA...SOUTH
FLORIDA...AND THE SOUTHEASTERN GULF OF MEXICO. OTHER SCATTERED
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE FOUND FROM 15N
TO 21N BETWEEN 71W AND 77W.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 31W/32W SOUTH OF 14N MOVING WEST 10 KT.
ITCZ SHOWERS AND THUNDERSTORMS.

TROPICAL WAVE ALONG 20N69W 15N71W 7N72W MOVING WEST 10 TO 15 KT.
IT IS NOT EASY TO FIND SHOWERS AND THUNDERSTORM DIRECTLY RELATED
TO THIS WAVE. THIS WAVE IS MOVING UNDERNEATH THE UPPER LEVEL
ANTICYCLONIC WIND FLOW WHICH COVERS MUCH OF THE CARIBBEAN SEA
WATERS.

SOUTHWESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 87W/88W SOUTH OF
16N MOVING WEST 10 TO 15 KT. NO CENTRAL AMERICA SHOWERS AND
THUNDERSTORMS ARE DIRECTLY RELATED TO THIS WAVE. STRONG SHOWERS
AND THUNDERSTORMS ARE IN THE EASTERN PACIFIC WITHIN 150 NM
SOUTHWEST OF THE SOUTHERN COAST OF COSTA RICA.

...ITCZ...

ITCZ 11N15W 9N30W 7N26W...9N33W 8N56W 9N62W. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS FROM 8N TO 10N BETWEEN 18W AND
21W...AND FROM 7N TO 8N BETWEEN 16N AND 17W. ISOLATED TO WIDELY
SCATTERED MODERATE/LOCALLY STRONG SHOWERS AND THUNDERSTORMS
ELSEWHERE FROM 3N TO 10N BETWEEN 20W AND 51W. SCATTERED MODERATE
TO ISOLATED STRONG SHOWERS FROM 9N TO 13N BETWEEN 51W AND 57W.
THIS SAME AREA YESTERDAY WAS EXPERIENCING SOME SPEED CONVERGENCE
IN THE QUICK-SCAT INFORMATION...AFTERNOON HEATING AND TRADEWIND
SHOWERS AND THUNDERSTORMS...ALL THE WHILE BEING TO THE EAST OF A
MIDDLE TO UPPER LEVEL TROUGH WHOSE BASE HAS SETTLED INTO THE
EASTERN CARIBBEAN SEA. OTHER SCATTERED MODERATE TO ISOLATED
STRONG SHOWERS AND THUNDERSTORMS ARE IN THE ATLANTIC OCEAN EAST
AND NORTHEAST OF THE EASTERN CARIBBEAN SEA...WITHIN 125 NM ON
EITHER SIDE OF 30N50W 23N56W 16N58W. UPPER LEVEL DIFFLUENT FLOW
ALSO MAY BE ENHANCING THIS CLOUDS AND PRECIPITATION IN THESE
AREAS.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE TO UPPER LEVEL NORTHERLY WIND FLOW COVERS THE GULF WATERS
WEST OF 90W. A MIDDLE TO UPPER LEVEL TROUGH HAS DUG ITS BASE
INTO THE NORTHWESTERN CARIBBEAN SEA JUST EAST OF THE YUCATAN
PENINSULA. MIDDLE TO UPPER LEVEL SOUTHERLY WIND FLOW HAS B BEEN
CARRYING MULTILAYERED MOISTURE AS FAR NORTH AS NORTH FLORIDA
EAST OF 86W...THANKS TO THE UPPER LEVEL RIDGE IN PLACE FROM THE
WESTERN CARIBBEAN SEA INTO THE ATLANTIC WATERS OFF THE COAST OF
GEORGIA AND THE CAROLINAS.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL TROUGH HAS DUG ITS WAY INTO THE EASTERN
CARIBBEAN SEA. UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE
AREA WEST OF THE TROUGH. EVEN THE ATMOSPHERE ON TOP OF TROPICAL
STORM ARLENE IS SURROUNDED BY UPPER LEVEL ANTICYCLONIC FLOW. AN
UPPER LEVEL RIDGE ACTUALLY PASSES FROM THE SOUTHWESTERN CORNER
OF THE AREA...ACROSS CUBA...INTO THE WESTERN ATLANTIC OCEAN
WATERS OFF THE COAST OF GEORGIA AND THE CAROLINAS.

THE ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE RUNS FROM THE SOUTHWESTERN CARIBBEAN SEA
TO 32N79W. MIDDLE TO UPPER LEVEL CYCLONIC FLOW...ASSOCIATED WITH
THE EASTERN CARIBBEAN SEA TROUGH...COVERS THE ATLANTIC WATERS
BETWEEN 52W AND 70W. A SURFACE 1015 MB LOW PRESSURE CENTER IS
NEAR 27N57W. A MIDDLE LEVEL CYCLONIC CENTER IS NEAR 31N63W...
SURROUNDED BY MIDDLE TO UPPER LEVEL DRY AIR WITHIN 250 TO 350 NM
ON EITHER SIDE OF 23N61W THROUGH 32N64W TO 40N66W. SCATTERED
MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS ARE IN
THE ATLANTIC OCEAN EAST AND NORTHEAST OF THE EASTERN CARIBBEAN
SEA...WITHIN 125 NM ON EITHER SIDE OF 30N50W 23N56W 16N58W.
UPPER LEVEL DIFFLUENT FLOW ALSO MAY BE ENHANCING THIS CLOUDS
AND PRECIPITATION IN THESE AREAS. A MIDDLE TO UPPER LEVEL TROUGH
RUNS THROUGH 32N24W TO 26N29W TO 20N34W. A SURFACE COLD FRONT
PASSES THROUGH 32N30W TO 31N39W. STATIONARY FRONT 31N39W BEYOND
32N44W. NO DEEP SHOWERS AND THUNDERSTORMS WITH THIS FRONT. BROAD
ANTICYCLONIC SURFACE WIND FLOW IS NORTH OF 18N BETWEEN AFRICA
AND 48W. ANOTHER SURFACE RIDGE PASSES THROUGH 32N66W TO 25N72W.

$$
MT


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