Tropical Weather Discussion
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000
AXNT20 KNHC 271043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON JUL 27 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.

...SPECIAL FEATURES...
A STRENGTHENED PRESSURE GRADIENT IS NOTED ACROSS THE CENTRAL
CARIBBEAN SEA WITH STRONG TO NEAR GALE FORCE WINDS OCCURRING AT
THIS TIME. AS THIS FEATURE PERSISTS...NEAR GALE TO GALE FORCE E-
NE WINDS ARE FORECAST TO BEGIN AROUND 28/0600 UTC LATE MONDAY
NIGHT INTO EARLY TUESDAY MORNING. SEE LATEST NWS HIGH SEAS
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE
DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 13N23W TO 20N20W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 18W-
25W WITH 850 MB RELATIVE VORTICITY FOCUSED NEAR THE SOUTHERN
EXTENT OF THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM
09N-15N BETWEEN 15W-25W.

TROPICAL WAVE EXTENDS FROM 09N38W TO 18N37W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 33W-
43W WITH GLOBAL MODEL INDICATED 850 MB RELATIVE VORTICITY
STRETCHED EAST-WEST FROM 10N-12N WITHIN THE INFLUENCE OF THE LOW
TO MIDDLE LEVEL TROUGHING. ISOLATED MODERATE CONVECTION IS
LARGELY CONFINED WITHIN THE VICINITY OF THE MONSOON TROUGH FROM
06N-10N BETWEEN 30W-36W.

TROPICAL WAVE EXTENDS FROM 09N59W TO 19N59W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 56W-63W WITH NO
SIGNIFICANT CONVECTION OCCURRING AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 11N77W TO 20N76W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 74W-83W
ON THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE ANCHORED OVER
THE CENTRAL ATLC NEAR 26N64W. ISOLATED MODERATE CONVECTION IS
FROM 18N-22N BETWEEN 74W-80W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N17W TO 12N25W TO 09N30W TO 09N37W TO 07N43W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N43W TO
07N51W TO 06N54W. ISOLATED MODERATE CONVECTION IS FROM 06N-10N
BETWEEN 21W-27W.

...DISCUSSION...

GULF OF MEXICO...
NORTHEAST TO EASTERLY FLOW ALOFT INFLUENCES THE GULF BASIN THIS
MORNING ON THE SOUTHEASTERN PERIPHERY OF A BROAD UPPER LEVEL
ANTICYCLONIC CIRCULATION ANCHORED OVER THE LOWER MISSISSIPPI
RIVER VALLEY AND ARKLATEX REGION. WHILE PROVIDING A GENERALLY
STABLE ENVIRONMENT ALOFT...A SURFACE WEAKNESS IN THE FORM OF A
1011 MB LOW CENTERED WEST OF THE TAMPA BAY AREA NEAR 28N83W AND
SURFACE TROUGHING EXTENDING GENERALLY WESTWARD FROM THE LOW TO
26N86W TO 27N90W IS PROVIDING FOCUS FOR ISOLATED SHOWERS AND
TSTMS. THIS ACTIVITY IS OCCURRING FROM 25N-28N BETWEEN 82W-88W
WITH MID-LEVEL ENERGY NOTED OVER THE EASTERN GULF THAT CONTINUES
TO PROVIDE MARGINAL LIFTING DYNAMICS FOR THE CONVECTION.
OTHERWISE...A WEAK SURFACE RIDGE ANCHORED BY A 10174 MB HIGH
CENTERED NEAR 22N84W WILL MAINTAIN GENTLE TO MODERATE
ANTICYCLONIC WINDS THROUGH LATE WEDNESDAY AS THE HIGH DRIFTS
GRADUALLY NORTHWESTWARD.

CARIBBEAN SEA...
WATER VAPOR IMAGERY INDICATES MOSTLY DRY CONDITIONS ALOFT OVER
MUCH OF THE CARIBBEAN BASIN THIS MORNING WHICH IS LIMITING ANY
WIDESPREAD AREAS OF STRONG AND DEEP CONVECTION. HOWEVER THE
PRESENCE OF A TROPICAL WAVE ALONG 77W IS GENERATING A FEW
ISOLATED SHOWERS AND TSTMS ACROSS EASTERN CUBA AND THE ADJACENT
COASTAL WATERS...ALONG WITH A FEW ISOLATED SHOWERS IN THE
WINDWARD PASSAGE REGION NORTH OF JAMAICA AND ACROSS THE CAYMAN
ISLANDS. OTHERWISE...THE PRIMARY MARINE IMPACT IS INCREASED
TRADES ACROSS CENTRAL PORTIONS REACHING STRONG TO NEAR GALE
FORCE BETWEEN 67W-79W. THIS AREA OF TRADES IS EXPECTED TO
PERSIST THROUGH THURSDAY.

...HISPANIOLA...
CURRENTLY...MOSTLY CLEAR SKIES AND FAIR CONDITIONS PREVAIL
ACROSS THE ISLAND FOR THE MORNING HOURS. GIVEN DRY AND STABLE
AIR ALOFT ALONG WITH RELATIVELY CLEAR SKIES NOTED ON SATELLITE
IMAGERY TO THE EAST...NO SIGNIFICANT DEEP CONVECTION IS EXPECTED
ACROSS THE ISLAND THROUGH MONDAY.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY INDICATED LONGWAVE TROUGHING OVER THE
WESTERN NORTH ATLC WITH A FEW EMBEDDED SHORTWAVES NEAR THE BASE
OF THE TROUGHING IN THE VICINITY OF THE DISCUSSION BORDER...ONE
NEAR 33N54W AND THE OTHER NEAR 33N69W. BOTH SUPPORT A STATIONARY
FRONT EXTENDING FROM 32N55W TO 31N59W INTO A 1014 MB LOW NEAR
33N71W TO 31N90W. LOW-LEVEL MOISTURE CONVERGENCE ALONG AND SOUTH
OF THE BOUNDARY ARE GENERATING ISOLATED SHOWERS AND TSTMS
GENERALLY N OF 29N BETWEEN 50W-60W...AND N OF 28N BETWEEN 65W-
79W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC...CENTRAL
AND EASTERN ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1026 MB HIGH CENTERED SW OF THE AZORES NEAR
35N30W. THE RIDGE AXIS EXTENDS FROM THE HIGH SW TO 26N52W THEN
WESTWARD TO THE CENTRAL BAHAMAS NEAR 24N78W.

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

$$
HUFFMAN


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