000
AXNT20 KNHC 171749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAY 17 2013

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
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 02N50W TO 09N46W MOVING W AT 15 KT.
THE WAVE REMAINS LOW-AMPLITUDE AND ON THE WESTERN EXTENT OF THE
ITCZ AXIS COINCIDING WITH A GLOBAL MODEL INDICATED AREA OF
MAXIMUM POTENTIAL VORTICITY AT 315K. TOTAL PRECIPITATABLE WATER
AND SATELLITE IMAGERY ALSO INDICATE A MAXIMUM IN LOW-LEVEL
MOISTURE CONVERGENCE AND CLOUDINESS IN THE VICINITY OF THE WAVE
AXIS. ISOLATED MODERATE CONVECTION IS FROM 04N-10N BETWEEN 45W-
57W. THE WAVE IS EXPECTED TO CONTINUE MOVING WESTWARD WITH
PRECIPITATION PROBABILITIES INCREASING OVER THE WEEKEND ACROSS
THE WINDWARD ISLANDS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N15W TO
06N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
06N20W TO 03N28W TO 01N34W TO 03N47W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 01N-05N BETWEEN THE PRIME MERIDIAN AND 09W...
AND FROM 01N-05N BETWEEN 27W-39W. SCATTERED MODERATE CONVECTION
IS FROM 03N-07N BETWEEN 14W-25W.

...DISCUSSION...

GULF OF MEXICO...
AT FIRST GLANCE ON VISIBLE SATELLITE IMAGERY THE GULF BASIN
REMAINS UNDER FAIRLY TRANQUIL CONDITIONS THIS AFTERNOON. WATER
VAPOR IMAGERY INDICATES UPPER LEVEL WESTERLY FLOW WITH MID-LEVEL
RIDGING PROVIDING FOR OVERALL STABLE CONDITIONS. AT THE
SURFACE...A RIDGE AXIS EXTENDS FROM THE SW NORTH ATLC REGION
NEAR 29N80W TO 26N95W AND IS PROVIDING SE WINDS GENERALLY IN THE
RANGE OF 5 TO 10 KT EAST OF 90W AND 10 TO 20 KT WEST OF 90W. THE
RIDGING IS EXPECTED TO REMAIN NEARLY STATIONARY OVER THE WEEKEND
INTO EARLY NEXT WEEK WITH LITTLE CHANGE REGARDING WIND SPEEDS
AND DIRECTION AS NOTED ABOVE. FINALLY...OF NOTE...VISIBLE
SATELLITE IMAGERY INDICATES MODERATELY DENSE SMOKE MOVING NORTH-
NORTHWESTWARD OFF THE SOUTHERN MEXICO COAST THAT COVERS A
PORTION OF THE SW GULF S OF 22N BETWEEN 92W-97W. THE SMOKE IS
DUE TO SEVERAL AGRICULTURAL FIRES ACROSS SOUTHERN MEXICO AND
NORTHERN CENTRAL AMERICA.

CARIBBEAN SEA...
DRY AND STABLE WESTERLY MIDDLE TO UPPER LEVEL FLOW IS NOTED ON
WATER VAPOR IMAGERY ACROSS THE NW CARIBBEAN WITH UPPER LEVEL
WINDS SHIFTING SLIGHTLY MORE WEST-SOUTHWEST OVER THE CENTRAL AND
EASTERN CARIBBEAN E OF 72W. MODERATELY DRY AIR PREVAILS ALOFT E
OF 72W...HOWEVER VISIBLE SATELLITE IMAGERY SHOWS A FEW PASSING
CIRRUS CLOUDS AND POSSIBLE CONVECTIVE DEBRIS CLOUDINESS FROM
CONVECTION OCCURRING OVER THE SW CARIBBEAN. SCATTERED SHOWERS
AND TSTMS ARE OCCURRING S OF 12N BETWEEN 76W-84W AND LIKELY WILL
PERSIST DUE TO LOW-LEVEL MOISTURE CONVERGENCE AND THE CLOSE
PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 09N/10N. OTHERWISE...
TRADES CONTINUE IN THE RANGE OF 10 TO 20 KT WITH SLIGHTLY HIGHER
WIND SPEEDS EXPECTED WITHIN 150 NM OF THE COAST OF COLOMBIA. A
FEW AREAS OF ISOLATED SHOWERS ARE OCCURRING IN THE VICINITY OF
JAMAICA AND THE ADJACENT COASTAL WATERS FROM 16N-20N BETWEEN 75W-
82W...HOWEVER THE OVERALL TRANQUIL WEATHER PATTERN IS EXPECTED
TO REMAIN IN PLACE THROUGH THE WEEKEND.

HISPANIOLA...
CURRENTLY NORTHWEST WINDS ALOFT ARE CONTINUING TO PROVIDE AN
OVERALL STABLE ENVIRONMENT OVER THE ISLAND THIS AFTERNOON.
DRYING ALOFT HAS TAKEN HOLD DURING THE LAST 24 TO 36 HOURS AND
MOST LOW-LEVEL MOISTURE AND ISOLATED SHOWERS RIDING TRADE WIND
FLOW ARE NOW LOCATED ACROSS THE ADJACENT SOUTHERN COASTAL WATERS
AND WELL WEST OF THE AREA IN THE VICINITY OF JAMAICA. WHILE THE
TRADE WIND FLOW REGIME WILL REMAIN PERSISTENT THROUGH THE
WEEKEND...AND GIVEN THE DRIER UPPER LEVEL FLOW PATTERN IN
PLACE...THE MOST LIKELY PRECIPITATION WILL BE ISOLATED SHOWERS
AND TSTMS DURING THE AFTERNOON AND EARLY EVENING HOURS ACROSS
THE ISLAND WHEN PEAK DAYTIME HEAT AND INSTABILITY OCCUR. ANY
AREAS THAT RECEIVE MEASUREABLE AMOUNTS OF RAINFALL WILL LIKELY
BE PRONE TO LOCALIZED FLOODING.

ATLANTIC OCEAN...
WEST-NORTHWESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY
OVER MUCH OF THE SW NORTH ATLC AS AN UPPER LEVEL TROUGH AXIS
CONTINUES TO MOVE INTO THE CENTRAL ATLC. THIS RATHER STABLE
REGIME ALOFT IS SUPPORTIVE OF A SURFACE RIDGE ANCHORED BY A 1024
MB HIGH CENTERED SOUTH OF BERMUDA NEAR 31N65W AND IS PROVIDING
FOR OVERALL FAIR CONDITIONS. ON THE SOUTHERN AND WESTERN
PERIPHERY OF THE RIDGE HOWEVER...A FEW ISOLATED SHOWERS AND
TSTMS ARE POSSIBLE AS NOTED ON SATELLITE IMAGERY AND MOSAIC
DOPPLER RADAR IMAGERY OFF THE COAST OF THE FLORIDA PENINSULA.
FARTHER EAST...THE PREVIOUSLY MENTIONED UPPER LEVEL TROUGH AXIS
EXTENDS FROM 30N47W SW TO 18N66W AND MARGINALLY SUPPORTS A
GRADUALLY WEAKENING STATIONARY ANALYZED FROM 32N56W TO 21N69W.
ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE
BOUNDARY N OF 23N. IN ADDITION ACROSS THE CENTRAL ATLC...A WEAK
1021 MB LOW IS CENTERED NEAR 29N47W WITH AN ASSOCIATED SURFACE
TROUGH FROM 27N43W TO 32N49W. POSSIBLE ISOLATED SHOWERS ARE
WITHIN 150 NM OF THE LOW CENTER...AND EAST OF THE LOW CENTER
FROM 26N-32N BETWEEN 40W-45W. OTHERWISE...THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1033 MB HIGH CENTERED NW OF THE AZORES NEAR
43N33W.

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

$$
HUFFMAN