000
AXNT20 KNHC 171803
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT MON MAY 17 2010

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC...

...TROPICAL WAVES...

AN ATLANTIC OCEAN SURFACE TROUGH IS ALONG 31W TO THE SOUTH OF 6N
MOVING WESTWARD 10 KT. ANY RELATED PRECIPITATION IS PART OF THE 
ITCZ PRECIPITATION.

...THE ITCZ...

FROM THE COAST OF SIERRA LEONE NEAR 7N12W TO 3N20W TO 2N30W...
ALONG 5N31W TO 4N40W TO 1N44W INTO THE EXTREME NORTHEASTERN 
CORNER OF BRAZIL NEAR 1N51W. SCATTERED MODERATE SHOWERS TO 
ISOLATED STRONG THUNDERSTORMS ARE FROM 3N TO 6N BETWEEN 34W AND 
46W...AND IN THE COASTAL WATERS/COASTAL PLAINS FROM BRAZIL TO 
SURINAME...FROM 2N TO 6N BETWEEN 50W AND 56W. ISOLATED MODERATE
SHOWERS ARE FROM 3N TO 6N TO THE EAST OF 34W.

...DISCUSSION...

THE GULF OF MEXICO AND THE CARIBBEAN SEA TO THE NORTH OF 15N
TO THE WEST OF 80W...
A MIDDLE TO UPPER LEVEL TROUGH IS DIGGING SOUTHEASTWARD IN THE 
PACIFIC OCEAN TOWARD PUNTA FALSA OF BAJA CALIFORNIA NEAR 
28N114W. UPPER LEVEL WESTERLY WIND MOVES FROM THE EASTERN PACIFIC
OCEAN NEAR 20N120W...ACROSS MEXICO TO THE SOUTH OF 26N. AN UPPER 
LEVEL TROUGH COVERS THE GULF OF MEXICO...FROM THE SOUTHWESTERN 
CORNER NORTHEASTWARD TO THE FLORIDA BIG BEND AND BEYOND.
PRECIPITATION THAT WAS OCCURRING BETWEEN THE GULF OF TEHUANTEPEC 
ON THE EASTERN PACIFIC OCEAN COAST OF MEXICO AND 90W NEAR
EL SALVADOR HAS ENDED. STRONG SHOWERS AND THUNDERSTORMS ARE IN 
THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...FROM 17N TO 20N 
BETWEEN 82W AND THE YUCATAN PENINSULA. MUCH OF THIS 
PRECIPITATION HAS BEEN WEAKENING WITH TIME AS THE CLOUD TOP 
TEMPERATURES HAVE BEEN WARMING. BROKEN TO OVERCAST MULTILAYERED 
CONVECTIVE DEBRIS CLOUDS COVER THE AREA FROM THE NORTHWESTERN 
CARIBBEAN SEA...ACROSS CUBA INTO THE STRAITS OF FLORIDA AND THE 
SOUTHEASTERN CORNER OF THE GULF OF MEXICO...TO THE SOUTH OF 25N
AND TO THE SOUTHEAST OF 25N85W 21N90W. A SURFACE TROUGH PASSES 
ON TOP OF THE FLORIDA BIG BEND INTO THE EAST CENTRAL GULF OF 
MEXICO. SHOWERS AND THUNDERSTORMS COVER THE AREA FROM CENTRAL 
FLORIDA NORTHWARD...INTO THE COASTAL WATERS OF NORTHEASTERN 
FLORIDA AND GEORGIA AND SOUTH CAROLINA. ISOLATED MODERATE 
SHOWERS ARE IN THE GULF OF MEXICO FROM 25N TO 28N BETWEEN THE 
FLORIDA WEST COAST AND 88W.

THE CARIBBEAN SEA FROM 15N SOUTHWARD AND FROM 80W EASTWARD...
A SURFACE-TO-LOW LEVEL TROUGH IS MOVING NORTHWESTWARD...RIGHT 
NOW PASSING THROUGH THE MONA PASSAGE...FROM 21N67W TO 17N69W TO 
15N70W. SHOWERS MAY BE WITHIN 30 NM TO 60 NM ON EITHER SIDE OF 
THIS TROUGH. SHOWERS ARE POSSIBLE IN SURFACE-TO-LOW LEVEL 
SOUTHEASTERLY WIND FLOW TO THE EAST OF 67W...IN LINES OF 
CONFLUENT SURFACE WIND FLOW. SOME SHOWERS ARE OCCURRING ON TOP 
OF THE EASTERN CARIBBEAN SEA ISLANDS AND IN PUERTO RICO. 
SURFACE-TO-LOW LEVEL EASTERLY WIND FLOW MOVES ACROSS THE 
CARIBBEAN SEA TO THE SOUTH OF 16N BETWEEN THE 21N67W 15N70W 
TROUGH AND CENTRAL AMERICA. ISOLATED MODERATE SHOWERS TO LOCALLY 
STRONG THUNDERSTORMS COVER THE AREA FROM 10N TO 15N BETWEEN 81W 
AND 85W...AS THE MOISTER AIR FROM THE WATERS REACHES THE 
COMPARATIVELY HIGHER ELEVATIONS OF CENTRAL AMERICA...DURING 
AFTERNOON HEATING.

THE ATLANTIC OCEAN...
BROAD UPPER LEVEL CYCLONIC FLOW FROM A TROUGH COVERS THE AREA
TO THE NORTH OF 30N TO THE WEST OF 38W. THIS CYCLONIC FLOW FROM 
A TROUGH SUPPORTS THE CURRENT STATIONARY FRONT THAT RUNS ALONG 
32N BETWEEN 53W AND BEYOND 63W. MIDDLE LEVEL TO UPPER LEVEL 
WESTERLY FLOW...SLIGHTLY CYCLONIC...COVERS THE ATLANTIC OCEAN 
FROM 20N TO 30N BETWEEN 40W AND 60W. A MIDDLE LEVEL TO UPPER 
LEVEL TROUGH IS ALONG 29N65W 21N68W. ISOLATED MODERATE SHOWERS
ARE FROM 22N TO 25N BETWEEN 65W AND 68W. SURFACE ANTICYCLONIC 
WIND FLOW MOVES AROUND A RIDGE THAT PASSES THROUGH 32N27W TO 
28N34W TO 27N46W TO A 1022 MB HIGH PRESSURE CENTER THAT IS NEAR 
29N63W...TO 32N76W. UPPER LEVEL ANTICYCLONIC WIND FLOW MOVES 
FROM THE SOUTH CENTRAL CARIBBEAN SEA NORTHEASTWARD TO 24N48W... 
AND THEN SOUTHEASTWARD TO THE CAPE VERDE ISLANDS. AN UPPER LEVEL 
TROUGH IS ALONG 31N12W 23N18W 15N27W...JUST TO THE WEST OF THE 
CAPE VERDE ISLANDS. 

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

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MT