Tropical Weather Discussion
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000
AXNT20 KNHC 270543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 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 09N19W TO 18N20W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 17W-
24W WITH 850 MB RELATIVE VORTICITY FOCUSED AROUND A 1014 MB LOW
CENTERED ALONG THE WAVE AXIS NEAR 12N. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 09N-15N BETWEEN 14W-23W.

TROPICAL WAVE EXTENDS FROM 08N33W TO 16N33W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 29W-40W
WITH GLOBAL MODEL INDICATED 850 MB RELATIVE VORTICITY STRETCHED
EAST-WEST FROM 10N-12N WITHIN THE INFLUENCE OF THE LOW TO MIDDLE
LEVEL TROUGHING. WIDELY SCATTERED MODERATE CONVECTION IS LARGELY
CONFINED WITHIN THE VICINITY OF THE MONSOON TROUGH FROM 06N-10N
BETWEEN 26W-35W.

TROPICAL WAVE EXTENDS FROM 07N56W TO 16N55W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 50W-60W WITH NO
SIGNIFICANT CONVECTION OCCURRING AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 11N74W TO 20N73W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 70W-82W
ON THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE ANCHORED OVER
THE CENTRAL ATLC NEAR 26N64W. NO SIGNIFICANT CONVECTION IS
OCCURRING WITH THE WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
11N15W TO 10N23W TO 08N33W TO 08N42W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 08N42W TO 08N52W TO 06N58W.
NO AREAS OF SIGNIFICANT DEEP CONVECTION ARE OCCURRING OUTSIDE OF
CONVECTION OCCURRING IN ASSOCIATION WITH THE TROPICAL WAVES
MENTIONED ABOVE.

...DISCUSSION...

GULF OF MEXICO...
NORTHEAST TO EASTERLY FLOW ALOFT INFLUENCES THE GULF BASIN THIS
EVENING 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 28N84W AND
SURFACE TROUGHING EXTENDING WESTWARD FROM THE LOW TO 27N87W TO
28N90W IS PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS. THIS
ACTIVITY IS OCCURRING FROM 23N-29N BETWEEN 82W-89W 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 1014 MB HIGH
CENTERED NEAR 24N89W 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 EVENING WHICH IS LIMITING ANY
WIDESPREAD AREAS OF STRONG AND DEEP CONVECTION. HOWEVER THE
PRESENCE OF A TROPICAL WAVE ALONG 74W 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. OTHERWISE...THE PRIMARY MARINE IMPACT
ARE 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 OVERNIGHT 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 33N56W AND THE OTHER NEAR 32N71W. BOTH SUPPORT A STATIONARY
FRONT EXTENDING FROM 33N56W TO 31N62W TO 33N73W TO 31N79W. LOW-
LEVEL MOISTURE CONVERGENCE ALONG AND SOUTH OF THE BOUNDARY ARE
GENERATING ISOLATED SHOWERS AND TSTMS GENERALLY N OF 28N BETWEEN
52W-63W...AND N OF 27N BETWEEN 67W-79W. OTHERWISE...THE
REMAINDER OF THE SW NORTH ATLC...CENTRAL AND EASTERN ATLC ARE
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1028 MB
HIGH CENTERED SW OF THE AZORES NEAR 36N32W. THE RIDGE AXIS
EXTENDS FROM THE HIGH SW TO 25N57W THEN WESTWARD TO THE NW
BAHAMAS NEAR 25N78W.

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

$$
HUFFMAN


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