[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 121045
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 12 2015

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 10N30W TO 20N28W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN 26W-36W AND
A MAXIMUM IN 850 MB RELATIVE VORTICITY ALONG THE WAVE AXIS NEAR
14N. NO SIGNIFICANT CONVECTION IS NOTED ON SATELLITE IMAGERY DUE
TO SAHARAN DUST THAT COVERS A LARGE PORTION OF THE TROPICAL
NORTH ATLC.

TROPICAL WAVE EXTENDS FROM 09N50W TO 19N47W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A RELATIVELY BROAD 700 MB GLOBAL MODEL
INDICATED TROUGH BETWEEN 45W-55W. NO SIGNIFICANT CONVECTION IS
NOTED ON SATELLITE IMAGERY DUE LARGELY TO SAHARAN DUST THAT
COVERS A LARGE AREA OF THE TROPICAL NORTH ATLC.

TROPICAL WAVE EXTENDS FROM 08N74W TO 19N72W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A SUBTLE 700 MB SHORTWAVE TROUGH AS PART
OF A LARGER MID-LEVEL TROUGH ASSOCIATED WITH AN UPPER LEVEL LOW
CENTERED OVER EASTERN CUBA. AS THE WAVE MOVES WEST AND COMES
UNDER THE INFLUENCE OF THE DYNAMICS OF THE UPPER LEVEL LOW...
SCATTERED MODERATE CONVECTION PERSISTS ACROSS A LARGE AREA FROM
15N-24N BETWEEN 62W-75W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
09N33W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N33W TO 08N37W TO 05N53W. SCATTERED MODERATE CONVECTION IS
FROM 03N-07N BETWEEN 20W-28W AND FROM 04N-11N BETWEEN 39W-43W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL RIDGE CENTERED OVER WEST TEXAS NEAR
33N101W CONTINUES TO BUILD IN OVER THE SE CONUS AND MUCH OF THE
NORTHERN TWO-THIRDS OF THE GULF BASIN THIS MORNING. WATER VAPOR
IMAGERY INDICATES MUCH OF THE NORTHEASTERLY FLOW ON THE
SOUTHEASTERN PERIPHERY OF THE RIDGE ALOFT IS RELATIVELY DRY
PROVIDING FOR AN OVERALL STABLE ENVIRONMENT AND QUIET CONDITIONS
AT THE SURFACE FOR THE DAYTIME PERIOD AHEAD. HOWEVER A FEW
ISOLATED SHOWERS AND TSTMS ARE OCCURRING ALONG A SURFACE TROUGH
BOUNDARY EXTENDING FROM NORTHERN FLORIDA NEAR 30N83W TO 26N83W.
OTHERWISE...A 1022 MB HIGH REMAINS ANCHORED NEAR 28N89W WHICH IS
SLOWLY DRIFTING WESTWARD. GENTLE TO MODERATE ANTICYCLONIC WINDS
ARE EXPECTED TO PERSIST THROUGH MONDAY INTO EARLY TUESDAY.

CARIBBEAN SEA...
NORTHWESTERLY FLOW ALOFT BECOMES MORE WESTERLY E OF 78W AS AN
OVERALL STABLE ENVIRONMENT EXISTS OVER THE NW CARIBBEAN. A FEW
ISOLATED SHOWERS ARE HOWEVER OCCURRING THIS MORNING FROM 18N-21N
BETWEEN 79W-85W. THE WESTERLY FLOW LIES ON THE SOUTHERN
PERIPHERY OF A VERY BROAD UPPER LEVEL LOW CENTERED OVER EASTERN
CUBA. STRONG MIDDLE TO UPPER LEVEL DYNAMICS ASSOCIATED WITH THE
LOW AND THE PRESENCE OF A TROPICAL WAVE ALONG 73W PROVIDING
AMPLE LOW-LEVEL CONVERGENCE ARE GENERATING A LARGE AREA OF
SCATTERED SHOWERS AND TSTMS ACROSS PORTIONS OF THE EASTERN AND
CENTRAL CARIBBEAN FROM 13N-24N BETWEEN 62W-75W. MOISTURE FROM
CONVECTION OCCURRING S OF 12N BETWEEN 75W-84W ACROSS THE SW
CARIBBEAN AND COSTA RICA IS ALSO BEING ADVECTED INTO THE UPPER
LEVEL LOW. WHILE THE UPPER LEVELS REMAIN FAIRLY DYNAMIC AND
ACTIVE THROUGHOUT THE DAY SUNDAY...MODERATE TO FRESH TRADES
PREVAIL WITH ONLY A SMALL AREA OF OCCASIONAL STRONG POSSIBLE
WITHIN CLOSE PROXIMITY TO THE COAST OF COLOMBIA. THESE TRADES
ARE EXPECTED TO PERSIST THROUGH TUESDAY.

...HISPANIOLA...
A BROAD UPPER LEVEL LOW IS CENTERED OVER EASTERN CUBA PLACING
THE ISLAND UNDER MAXIMUM MOIST SOUTHWESTERLY FLOW ALOFT THIS
MORNING. GIVEN THE MIDDLE TO UPPER LEVEL DIFFLUENCE AND PRESENCE
OF A TROPICAL WAVE ALONG 73W...SCATTERED SHOWERS AND TSTMS ARE
OCCURRING ACROSS MUCH OF THE ISLAND THIS MORNING AND THIS
ACTIVITY IS EXPECTED TO PERSIST THROUGHOUT THE DAY ON SUNDAY.
THE UPPER LEVEL LOW IS FORECAST TO MOVE SLOWLY WEST-NORTHWEST
LEAVING HISPANIOLA WITHIN THE AREA OF MAXIMUM DIFFLUENCE ALOFT
THROUGH EARLY MONDAY RESULTING IN CONTINUED CONVECTION AND THE
POSSIBILITY OF LOCALIZED FLOODING AND POSSIBLE MUDSLIDES.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS CENTERED OVER EASTERN CUBA NEAR 21N75W
SUPPORTING A BROAD AREA OF SCATTERED SHOWERS AND TSTMS ACROSS
PORTIONS OF THE SW NORTH ATLC FROM 18N-24N BETWEEN 62W-76W.
OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE
INFLUENCE OF A WEAK SURFACE RIDGE WITH AXIS ALONG 26N. TO THE
NORTH OF THE AXIS...ALONG THE DISCUSSION AREA BORDER...A PAIR OF
MID-LEVEL SHORTWAVE TROUGHS ARE NOTED ON WATER VAPOR IMAGERY...
ONE NEAR 32N60W AND ANOTHER OFFSHORE OF THE NORTH CAROLINA
COASTLINE NEAR 34N74W. BOTH SHORTWAVES SUPPORT LOW PRESSURE
AREAS TO THE NORTH OF 32N...WITH A STATIONARY FRONT ANALYZED
FROM 33N63W TO 33N71W. LOW-LEVEL MOISTURE CONTINUES TO POOL
ALONG AND TO THE SOUTH OF THE STATIONARY FRONT GENERATING
ISOLATED SHOWERS AND TSTMS N OF 28N BETWEEN 56W-72W...AND N OF
31N W OF 75W. FINALLY...THE CENTRAL AND EASTERN ATLC ARE
DOMINATED BY AN INFLUENCE OF A SURFACE RIDGE ANCHORED BY A
NEARLY STATIONARY 1027 MB HIGH CENTERED SE OF THE AZORES NEAR
37N24W AND A 1025 MB HIGH CENTERED NEAR 29N43W.

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

$$
HUFFMAN
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