[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 221041
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 07N35W TO 15N35W 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 03N-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 05N-08N BETWEEN 32W-39W.

TROPICAL WAVE EXTENDS FROM 04N47W TO 12N47W MOVING W AT 15 KT.
THE WAVE LIES WITHIN A RELATIVE MAXIMUM ON TOTAL PRECIPITABLE
WATER IMAGERY FROM 06N-20N BETWEEN 45W-50W. 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 10N81W TO 19N81W 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 MORNING. 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 12N16W TO
10N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
10N20W TO 07N35W TO 04N46W. ISOLATED MODERATE CONVECTION IS
FROM 01N-05N BETWEEN 31W-40W.

...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
SOUTHWEST ACROSS THE NORTHERN FLORIDA PENINSULA. AS OF 22/0900
UTC...A SURFACE TROUGH EXTENDED FROM NEAR JACKSONVILLE FLORIDA
WEST-SOUTHWEST TO NEAR 28N88W PROVIDING FOCUS FOR ISOLATED
SHOWERS N OF 26N E OF 92W. OTHERWISE...THE REMAINDER OF THE
BASIN IS UNDER THE INFLUENCE OF WEAK SURFACE RIDGING EXTENDING
FROM THE DELMARVA REGION SOUTHWEST TO EAST-CENTRAL MEXICO NEAR
22N98W. 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. 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 21N73W. THE TROUGH AXIS
DIPS SOUTH-SOUTHWEST TO A BASE OVER THE SW CARIBBEAN NEAR 13N77W
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 72W-86W. A FEW ISOLATED SHOWERS AND TSTMS ARE
HOWEVER OCCURRING IN THE VICINITY OF THE CAYMAN ISLANDS FROM 18N-
21N BETWEEN 79W-83W. 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 SW OF A LINE FROM NORTHERN BELIZE
NEAR 18N88W TO NORTHERN COLOMBIA NEAR 11N75W...INCLUDING INLAND
PORTIONS OF HONDURAS...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 12N E OF
72W...THAT STRETCH NORTHEASTWARD INTO THE ADJACENT WATERS OF THE
SW NORTH ATLC.

HISPANIOLA...
CURRENTLY CONDITIONS REMAIN RELATIVELY TRANQUIL THIS MORNING
ACROSS THE ISLAND. WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL
LOW IS CENTERED NORTH OF THE ISLAND NEAR 21N73W WITH PRIMARILY
MOIST SOUTHWESTERLY FLOW ALOFT LOCATED EAST OF A TROUGH AXIS
WHICH EXTENDS JUST WEST OF THE ISLAND. 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 DUE TO
PEAK DAYTIME HEATING AND INSTABILITY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE SE CONUS NEAR
34N84W SUPPORTS A WEAK 1018 MB LOW CENTERED NEAR 33N78W AND THE
ASSOCIATED FRONTAL BOUNDARY EXTENDING TO THE COAST NEAR 30N81W.
WIDELY SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER THE FAR NW
PORTION OF THE SW NORTH ATLC N OF 29N W OF 77W. FARTHER
SOUTHEAST...ENERGY THAT HAS FRACTURED AWAY FROM A TROPICAL WAVE
MOVING ACROSS THE WESTERN CARIBBEAN SEA REMAINS ANALYZED AS A
SURFACE TROUGH FROM 24N77W TO 28N74W AND IS PROVIDING FOCUS FOR
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM 25N-
29N BETWEEN 72W-77W. 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 1033 MB HIGH CENTERED WEST OF THE AZORES
NEAR 39N33W. A STABLE DRY AIRMASS COVERS MUCH OF THE EASTERN
ATLC INDICATED BY A LARGE AREA OF SUSPENSED SAHARAN 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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