[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 23 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
1645 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 01N50W TO 07N49W MOVING W AT 15-20
KT. THE WAVE REMAINS ON THE WESTERN EXTENT OF THE ITCZ AXIS AND
IS LOCATED WITHIN AN AREA OF LOW-LEVEL CYCLONIC TURNING.
SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN
45W-51W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO
08N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
08N18W TO 04N29W TO 03N48W. ISOLATED MODERATE CONVECTION IS FROM
05N-12N BETWEEN 16W-21W...AND FROM THE EQUATOR TO 06N BETWEEN
21W-32W. SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN
35W-43W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES THAT MIDDLE TO UPPER LEVEL
NORTHWESTERLY FLOW CONTINUES TO PROVIDE AN OVERALL MODERATELY
DRY AND STABLE AIRMASS ALOFT OVER MUCH OF THE BASIN THIS
AFTERNOON. FURTHER SUPPORTING THE STABLE REGIME IN PLACE A
SURFACE RIDGE REMAINS ANCHORED BY A 1018 MB HIGH CENTERED OVER
THE NE GULF WATERS NEAR 28N87W. ON THE SOUTHERNWESTERN PERIPHERY
OF THIS SURFACE RIDGE...LIGHT SOUTHEASTERLY WINDS PREVAIL IN THE
RANGE OF 5 TO 15 KT. EAST OF THE RIDGE...A WEAK AREA OF LOWER
PRESSURE IS OBSERVED ACROSS THE FLORIDA PENINSULA AND ADJACENT
COASTAL WATERS IN THE SW NORTH ATLC WITH A SURFACE TROUGH
ANALYZED FROM OFFSHORE OF THE CAROLINAS ACROSS THE SOUTHERN
FLORIDA PENINSULA AND INTO THE SE GULF NEAR 25N84W. MOSTLY CLEAR
SKIES ARE NOTED ON SATELLITE IMAGERY AS THE HIGH AND RIDGE IS
EXPECTED TO REMAIN IN PLACE THROUGH THE WEEKEND.

CARIBBEAN SEA...
NORTHWEST TO WESTERLY FLOW ALOFT DOMINATES OVER THE CARIBBEAN
WITH WATER VAPOR IMAGERY INDICATING MODERATELY DRY AIR OVER A
NARROW AREA FROM THE YUCATAN CHANNEL TO 15N70W. OTHERWISE AT THE
SURFACE...THE TROPICAL WAVE PREVIOUSLY ANALYZED IN THE SW
CARIBBEAN HAS BECOME TO DIFFICULT TO DISCERN ON SATELLITE
IMAGERY AND THE ENERGY ASSOCIATED WITH IT HAS MERGED INTO THE
SEMI-PERMANENT LOW-LEVEL COLOMBIAN GYRE. SCATTERED SHOWERS AND
ISOLATED TSTMS CONTINUE OVER THE SW CARIBBEAN HOWEVER S OF 14N
BETWEEN 75W-81W...AND S OF 11N BETWEEN 81W-84W. FARTHER EAST...
LOW-LEVEL MOISTURE INCREASES OVER THE NE CARIBBEAN NEAR THE BASE
OF A MIDDLE TO UPPER LEVEL TROUGH THAT EXTENDS FROM THE FAR
WESTERN PORTION OF THE SW NORTH ATLC GENERATING WIDELY SCATTERED
SHOWERS AND ISOLATED TSTMS EAST OF A LINE FROM SOUTHWESTERN
HISPANIOLA NEAR 18N74W TO THE ABC ISLANDS NEAR 12N68W. E-SE
TRADES ARE EXPECTED TO PERSIST THROUGH FRIDAY WITH WINDS
SHIFTING MORE NORTHEASTERLY OVER THE NW CARIBBEAN AS A FRONTAL
TROUGH MOVES ACROSS THE SW NORTH ATLC REGION.

HISPANIOLA...
CURRENTLY NORTHWEST WINDS ALOFT ARE OVER THE ISLAND WITH
SATELLITE IMAGERY INDICATING LOW-LEVEL MOISTURE CONTINUING TO
ADVECT ACROSS THE ISLAND INCREASING TO THE EAST OVER PUERTO RICO
AND THE LEEWARD ISLANDS. ISOLATED SHOWERS ARE OCCURRING EAST OF
72W AND THIS CONVECTION IS EXPECTED TO CONTINUE AND INCREASE IN
COVERAGE THROUGHOUT THE LATE AFTERNOON INTO THE EARLY EVENING
HOURS WITH PEAK DAYTIME HEATING AND INSTABILITY IN PLACE.
OVERALL SOUTHEAST WINDS ARE EXPECTED TO PERSIST THROUGH EARLY
SATURDAY AS A FRONTAL TROUGH MOVES ACROSS THE SW NORTH ATLC AND
BY SATURDAY SURFACE TROUGHING WILL LIE ACROSS THE ISLAND
PROVIDING FOR INCREASED PRECIPITATION CHANCES OVER THE REMAINDER
OF THE WEEKEND INTO EARLY MONDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS INDICATED ON WATER
VAPOR IMAGERY WITH AXIS EXTENDING FROM OFFSHORE OF THE CAROLINAS
TO A BASE OVER HISPANIOLA...PUERTO RICO...AND THE NE CARIBBEAN
SEA. THE STRONGEST UPPER LEVEL DYNAMICS LIE N OF 25N OFF THE
FLORIDA PENINSULA COAST AS SCATTERED SHOWERS AND TSTMS ARE
OCCURRING N OF 25N BETWEEN 74W AND A SURFACE TROUGH AXIS
ANALYZED FROM 32N78W TO THE FLORIDA COAST NEAR 26N80W AND INTO
THE SE GULF OF MEXICO WATERS NEAR 24N84W. THE REMAINDER OF THE
SW NORTH ATLC AND CENTRAL ATLC IS DOMINATED BY A SURFACE RIDGE
ANCHORED BY A 1029 MB HIGH CENTERED EAST OF BERMUDA NEAR 33N59W.
LOW-LEVEL MOISTURE PREVAILS ON THE SOUTHERN PERIPHERY OF THE
RIDGE WITH POSSIBLE ISOLATED SHOWERS S OF 24N BETWEEN 50W-72W.
AN AMPLIFIED UPPER LEVEL RIDGE AND ANTICYCLONE IS CENTERED NEAR
30N54W WITH UPPER LEVEL TROUGHING NOTED ON WATER VAPOR IMAGERY W
OF 46W. THIS TROUGHING SUPPORTS A STATIONARY FRONT ANALYZED INTO
THE DISCUSSION AREA NEAR 32N39W TO 28N40W TO 25N45W. ISOLATED
SHOWERS ARE OCCURRING WITHIN 210 NM EAST OF THE BOUNDARY. THE
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1034 MB HIGH CENTERED WELL NE OF THE
AZORES NEAR 48N21W.

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

$$
HUFFMAN


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