[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 111047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 11 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 11N29W TO 18N28W MOVING W AT 10-15
KT. THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ AXIS COINCIDES
WITH A GLOBAL MODEL INDICATED 700 MB TROUGH AND ASSOCIATED
VORTICITY MAXIMUM IN THE VICINITY OF 14N29W. TOTAL PRECIPITABLE
WATER IMAGERY SHOWS A RELATIVE MOISTURE MAXIMUM FROM 11N-17N
BETWEEN 24W-34W. ISOLATED MODERATE CONVECTION IS FROM 10N-16N
BETWEEN 27W-31W.

TROPICAL WAVE EXTENDS FROM 06N43W TO 14N41W MOVING W AT 10 KT.
THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ AXIS WITH LOW-LEVEL
STREAMLINE ANALYSIS INDICATING CYCLONIC TURNING OF THE LOW-LEVEL
WIND FIELD VERTICALLY THROUGH 700 MB S OF 14N BETWEEN 38W-47W. A
SAHARAN AIR LAYER REMAINS ON THE NORTHERN PERIPHERY OF THE WAVE
AXIS AND THIS IS RESULTING IN LIMITED CONVECTION WITH THE WAVE
AT THIS TIME. ISOLATED MODERATE CONVECTION IS FROM 07N-11N
BETWEEN 41W-44W.

TROPICAL WAVE EXTENDS FROM 12N76W TO 19N75W MOVING W AT 15-20
KT. THE WAVE...THE SOUTHERN EXTENT OF ENERGY ASSOCIATED WITH THE
REMNANTS OF CHANTAL...CONTINUES WESTWARD WHILE PARTIAL ENERGY
FRACTURES W-NW AS A SURFACE TROUGH AND NO DEFINED LOW-LEVEL
CIRCULATION CENTER. PLENTY OF LOW-LEVEL MOISTURE CONVERGENCE AND
MID-LEVEL VORTICITY ARE AIDING IN GENERATING SCATTERED MODERATE
CONVECTION FROM 16N-27N BETWEEN 68W-77W...INCLUDING PORTIONS OF
HISPANIOLA...THE WINDWARD PASSAGE...THE TURKS AND CAICOS
ISLANDS...AND THE SE BAHAMAS. THE WAVE IS EXPECTED TO TRACK
ACROSS THE WESTERN CARIBBEAN SEA OVER THE WEEKEND.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
15N24W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
15N24W TO 14N29W TO 07N43W TO 02N51W. SCATTERED MODERATE
CONVECTION IS FROM 07N-11N BETWEEN 13W-21W. ISOLATED MODERATE
CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN
30W-42W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES EAST-NORTHEASTERLY UPPER LEVEL
FLOW NORTH OF A BROAD TROUGH AXIS EXTENDING FROM AN UPPER LEVEL
LOW CENTERED OVER THE FLORIDA STRAITS NEAR 23N80W TO OVER EAST-
CENTRAL MEXICO NEAR 22N101W. MOSTLY DRY AND STABLE AIR ALOFT IS
NOTED OVER THE NORTHERN GULF WATERS THIS MORNING WHILE A SURFACE
RIDGE ANCHORED BY A 1018 MB HIGH CENTERED NEAR 27N88W LIES
BENEATH PROVIDING FOR OVERALL TRANQUIL CONDITIONS ACROSS THE NW
GULF. A SLIGHT WEAKNESS IN THE RIDGE IS ANALYZED AS A SURFACE
TROUGH FROM NORTHERN FLORIDA NEAR 30N82W TO 26N84W. WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM N OF 26N
W OF 90W AS INDICATED BY MOSAIC DOPPLER RADAR IMAGERY. ACROSS
PORTIONS OF THE SW GULF...WITHIN MOSTLY WESTERLY FLOW ALOFT ON
THE SOUTHERN PERIPHERY OF THE UPPER LEVEL TROUGHING...MIDDLE TO
UPPER LEVEL MOISTURE INCREASES WITH ISOLATED SHOWERS OCCURRING S
OF 24N W OF 94W. LOOKING AHEAD...THE WEAKNESS IN THE SURFACE
RIDGING BETWEEN THE SW NORTH ATLC AND GULF WILL PROVIDE FOR THE
REMNANT SURFACE TROUGHING OF CHANTAL TO TRACK W-NW THROUGH THE
WEEKEND ACROSS THE FLORIDA STRAITS AND SOUTHERN FLORIDA
PENINSULA.

CARIBBEAN SEA...
THE PRIMARY FOCUS FOR THE CARIBBEAN IS THE REMNANTS OF
CHANTAL...ANALYZED AS AN OPEN TROPICAL WAVE ALONG 76W. MUCH OF
THE CONVECTION ASSOCIATED WITH THE WAVE IS LOCATED N OF 16N
BETWEEN 67W-78W...INCLUDING HISPANIOLA...PORTIONS OF THE
WINDWARD PASSAGE...EASTERN CUBA...AND JAMAICA. THE WAVE AND AREA
OF MOISTURE IS EXPECTED TO TRACK WESTWARD OVER THE NEXT 24 TO 36
HOURS PROVIDING INCREASED RAINFALL CHANCES FOR CUBA...JAMAICA...
AND THE CAYMAN ISLANDS THROUGH THE WEEKEND. OVER THE WESTERN
CARIBBEAN...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER NICARAGUA NEAR 13N85W. MIDDLE TO UPPER LEVEL MOISTURE
REMAINS ACROSS MUCH OF CENTRAL AMERICA AND THE NW CARIBBEAN THIS
MORNING WITH UPPER LEVEL DIFFLUENCE CONTINUING TO GENERATE
SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS S OF 21N W OF 82W.
FARTHER SOUTH ACROSS THE SW CARIBBEAN...THE MONSOON TROUGH AXIS
EXTENDS ALONG 09N/10N FROM NORTHERN COLOMBIA TO COSTA RICA AND
IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND TSTMS S OF 13N
BETWEEN 75W-87W. AS THE REMNANTS OF CHANTAL TRACK NORTH OF THE
BASIN OVER THE WEEKEND...THE BEGINNING OF NEXT WEEK WILL SEE A
RETURN TO E-SE TRADES IN THE RANGE OF 10 TO 20 KT WITH STRONGER
WINDS POSSIBLE IN THE VICINITY OF THE NORTHERN COLOMBIA COAST.

HISPANIOLA...
CURRENTLY...THE REMNANTS OF CHANTAL...ARE PRODUCING SCATTERED
SHOWERS AND ISOLATED TSTMS ACROSS THE ISLAND THIS MORNING. SOME
OF THIS RAINFALL IS LOCALLY HEAVY WITH THE POTENTIAL FLOODING.
THIS AREA OF PRECIPITATION IS EXPECTED TO MOVE W-NW OVER THE
NEXT 24 TO 36 HOURS AND CONDITIONS ACROSS HISPANIOLA ARE
EXPECTED TO GRADUALLY IMPROVE BY LATE FRIDAY INTO EARLY
SATURDAY. THEREAFTER...E-SE TRADES WILL RESUME ACROSS THE REGION
WITH THE MORE TYPICAL AFTERNOON SHOWERS AND TSTMS OCCURRING
ACROSS THE ISLAND DURING THE WEEKEND INTO EARLY NEXT WEEK.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE FLORIDA STRAITS
NEAR 24N80W THAT IS PROVIDING THE SW NORTH ATLC WITH A WEAKNESS
IN THE SURFACE RIDGING TO DRAW THE REMNANTS OF CHANTAL W-NW FROM
THE NORTH-CENTRAL CARIBBEAN SEA AND HISPANIOLA ACROSS THE
BAHAMAS AND SOUTH FLORIDA THROUGH THE UPCOMING WEEKEND.
CURRENTLY ANALYZED AS A SURFACE TROUGH FROM 20N74W TO 25N72W...
SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 19N BETWEEN 68W-
77W...INCLUDING THE TURKS AND CAICOS ISLANDS AND SE BAHAMAS.
SURFACE RIDGING ANCHORED BY A 1022 MB HIGH CENTERED NE OF
BERMUDA NEAR 34N61W WILL GRADUALLY SHIFT EASTWARD OVER THE NEXT
24 TO 36 HOURS AND ALLOW THE TROUGHING TO MAKE ITS WAY TOWARDS
THE FLORIDA PENINSULA AND AREAS OFF THE EASTERN COASTLINE.
FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 31N56W THAT
REMAINS AT THE SOUTHWESTERN EXTENT OF A STATIONARY FRONT
ANALYZED FROM 35N40W TO 31N48W. MOISTURE ASSOCIATED WITH THE
UPPER LEVEL LOW AND A WEAK SURFACE TROUGH ANALYZED FROM 25N50W
TO 31N50W ARE GENERATING ISOLATED SHOWERS FROM 22N-32N BETWEEN
49W-55W. GLOBAL MODELS INDICATE THIS UPPER LEVEL FEATURE WILL
DRIFT WESTWARD ACROSS THE SW NORTH ATLC OVER THE COMING DAYS.
FINALLY...THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1021 MB HIGH CENTERED SW OF THE AZORES NEAR
35N31W. A SAHARAN AIR LAYERS CONTINUES TO BE THE OVERALL
DOMINATE FEATURE PROVIDING FAIRLY STABLE CONDITIONS N OF 18N E
OF 47W.

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

$$
HUFFMAN


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