[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 220550
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUN 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 05N33W TO 15N33W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH A WEAK 700 MB TROUGH AND A RELATIVE
MAXIMUM IN DEEP LAYER MOISTURE NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY FROM 02N-09N BETWEEN 28W-34W. ALSO OF NOTE...THE WAVE IS
LOCATED WITHIN AN AREA OF CLEARING EMBEDDED IN THE SAHARAN AIR
LAYER SURROUNDING THE WAVE AXIS. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 06N-08N BETWEEN 29W-33W.

TROPICAL WAVE EXTENDS FROM 07N46W TO 16N47W MOVING W AT 15 KT.
THE WAVE LIES WITHIN A RELATIVE MAXIMUM ON TOTAL PRECIPITABLE
WATER IMAGERY FROM 07N-22N BETWEEN 43W-48W. THE SAHARAN AIR
LAYER AS NOTED ON GOES-R PG IMAGERY REMAINS A STRONG SIGNAL AND
CONTINUES TO SURPRESS ANY SIGNIFICANT DEEP CONVECTION IN THE
VICINITY OF THE WAVE...INCLUDING S OF 10N IN CLOSER PROXIMITY TO
THE ITCZ AXIS.

TROPICAL WAVE EXTENDS FROM 11N81W TO 19N80W MOVING W AT 15 KT.
THE WAVE ALIGNS WITH WEAK 700 MB TROUGHING THAT EXTENDS FROM THE
SW CARIBBEAN OVER CENTRAL CUBA AND INTO THE SW NORTH ATLC OVER
THE BAHAMAS. PARTIAL ENERGY FROM THE WAVE HAS FRACTURED NORTH-
NORTHWESTWARD AND REMAINS ANALYZED AS A SURFACE TROUGH PRODUCING
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS THIS EVENING. AS FOR
THE WAVE...IT REMAINS BENEATH UNFAVORABLE CONDITIONS ALOFT AS
NORTHWEST FLOW IN THE UPPER LEVELS CONTINUES TO PROVIDE AN
OVERALL STABLE ENVIRONMENT ACROSS PORTIONS OF THE CENTRAL AND
WESTERN CARIBBEAN. THE WAVE IS EXPECTED TO CONTINUE WESTWARD AND
BRING INCREASED CLOUDINESS AND HIGHER CHANCES FOR PRECIPITATION
ACROSS CENTRAL AMERICA OVER THE NEXT 24 TO 48 HOURS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO
10N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
10N20W TO 07N33W TO 07N46W TO 05N53W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN 26W-38W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN MIDDLE TO UPPER LEVEL LOW IS
CENTERED OVER THE SE CONUS THAT SUPPORTS WEAK SURFACE TROUGHING
EXTENDING FROM THE SW NORTH ATLC OFFSHORE OF THE CAROLINAS WEST-
SOUTHWEST ACROSS EXTREME NORTHERN FLORIDA INTO EASTERN
LOUISIANA. AS OF 22/0300 UTC...A SURFACE TROUGH EXTENDED FROM
NEAR JACKSONVILLE FLORIDA TO NORTH OF THE TAMPA BAY AREA NEAR
28N83W THAT IS PROVIDING FOCUS FOR ISOLATED SHOWERS N OF 27N E
OF 85W. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH CENTERED
NEAR 28N92W. EAST-SOUTHEAST WINDS IN THE RANGE OF 5 TO 15 KT ARE
NOTED ON EARLIER SCATTEROMETER PASSES AND THE LATEST SHIP...
BUOY...AND OIL PLATFORM OBSERVATIONS INDICATE THESE CONDITIONS
SHOULD PERSIST THROUGH THE OVERNIGHT HOURS. THE RIDGING SHOULD
MAINTAIN ITSELF SUNDAY AND THROUGHOUT MUCH OF THE WEEK AHEAD.

CARIBBEAN SEA...
THE CARIBBEAN IS LARGELY INFLUENCE BY A MIDDLE TO UPPER LEVEL
LOW CENTERED NORTH OF HISPANIOLA NEAR 21N72W. THE TROUGH AXIS
DIPS SOUTH-SOUTHWEST TO A BASE OVER THE SW CARIBBEAN NEAR 11N77W
WITH ANOTHER WEAKER AXIS EXTENDING FROM OVER JAMAICA NEAR 18N78W
TO OVER THE YUCATAN CHANNEL NEAR 22N86W. WATER VAPOR IMAGERY
INDICATES THE AREAS WITHIN THE TROUGHING ARE RELATIVELY DRY AND
STABLE ALOFT WHICH IS PROVIDING FOR OVERALL TRANQUIL CONDITIONS
N OF 14N BETWEEN 73W-83W. A FEW ISOLATED SHOWERS AND TSTMS ARE
HOWEVER OCCURRING IN THE VICINITY OF THE CAYMAN ISLANDS AND
JAMAICA FROM 18N-21N BETWEEN 78W-82W. OTHERWISE ON THE SOUTHWEST
PERIPHERY OF THE TROUGH...NORTH-NORTHWESTERLY FLOW ALOFT
DOMINATES AND IS PROVIDING FOR SUFFICIENT UPPER LEVEL DIFFLUENCE
TO SUPPORT SCATTERED SHOWERS AND TSTMS S OF 15N W OF 80W...
INCLUDING INLAND PORTIONS OF NICARAGUA AND COSTA RICA. A
TROPICAL WAVE ALONG 81W WILL ALSO CONTINUE TO MOVE WESTWARD OVER
THE NEXT FEW DAYS AND INCREASE CLOUDINESS AND PRECIPITATION FOR
CENTRAL AMERICA INTO EARLY NEXT WEEK. EAST OF THE UPPER LEVEL
TROUGH AXIS...SOUTHWESTERLY FLOW ALOFT CONTINUES TO ADVECT
MOISTURE FROM OVER NORTHERN SOUTH AMERICA TOWARDS THE MONA
PASSAGE AND PUERTO RICO. MOST OF THIS MOISTURE REMAINS AS
INCREASED CLOUD COVER ACROSS THE EASTERN CARIBBEAN...HOWEVER A
FEW ISOLATED LOW-TOPPED SHOWERS ARE NOTED ON SATELLITE IMAGERY N
OF 13N E OF 72W...THAT STRETCH NORTHEASTWARD INTO THE ADJACENT
WATERS OF THE SW NORTH ATLC.

HISPANIOLA...
CURRENTLY CONDITIONS REMAIN RELATIVELY TRANQUIL FOR THE
OVERNIGHT ACROSS THE ISLAND AS LATE EVENING CONVECTION HAS
DIMINISHED. WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL LOW IS
CENTERED NORTH OF THE ISLAND NEAR 21N72W WITH PRIMARILY MOIST
SOUTHWESTERLY FLOW ALOFT LOCATED EAST OF A TROUGH AXIS WHICH
BISECTS THE ISLAND ALONG 72W. GLOBAL MODEL DATA INDICATES THE
LOW WILL WEAKEN OVER THE NEXT FEW DAYS AND LIFT GRADUALLY
NORTHWARD WITH SOUTHWESTERLY FLOW ALOFT BECOMING DOMINANT
THROUGH EARLY NEXT WEEK. AS A RESULT...THE ATMOSPHERE WILL FAVOR
BECOMING MORE UNSTABLE DURING THE AFTERNOON AND EVENING HOURS
WITH SCATTERED SHOWERS AND TSTMS EXPECTED WITH PEAK DAYTIME
HEATING AND INSTABILITY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE SE CONUS NEAR
35N84W SUPPORTS A WEAK 1018 MB LOW CENTERED NEAR 33N78W AND THE
ASSOCIATED FRONTAL BOUNDARY EXTENDING TO THE COAST NEAR 31N81W.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER THE FAR NW PORTION
OF THE SW NORTH ATLC N OF 29N W OF 78W. FARTHER SOUTHEAST...
ENERGY THAT HAS FRACTURED AWAY FROM A TROPICAL WAVE MOVING
ACROSS THE WESTERN CARIBBEAN SEA REMAINS ANALYZED AS A SURFACE
TROUGH FROM 22N75W TO 27N73W AND IS PROVIDING FOCUS FOR WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 120 NM
WEST OF THE SURFACE TROUGH AXIS. THIS AREA OF INCREASED MOISTURE
AND PRECIPITATION IS EXPECTED TO CONTINUE AN OVERALL WEST-
NORTHWEST MOVEMENT OVER THE NEXT FEW DAYS WITH CLOUDINESS AND
PRECIPITATION CHANCES ELEVATED FOR THE WESTERN BAHAMAS AND
FLORIDA PENINSULA OVER THE WEEKEND. OTHERWISE...THE REMAINDER OF
THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1036 MB HIGH CENTERED WEST OF THE AZORES
NEAR 39N32W. A STABLE DRY AIRMASS COVERS MUCH OF THE EASTERN
ATLC INDICATED BY THE LARGE AREA OF DUST THAT EXTENDS FROM THE
COAST OF AFRICA TO 50W.

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

$$
HUFFMAN


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