[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLC WITH AXIS ALONG 18W/19W FROM
08N TO 20N...MOVING W AT AROUND 10 KT. FORWARD SPEED ESTIMATES
WERE BASED ON LONG-TERM SATELLITE TRENDS. THIS WAVE POSITION WAS
RE-ANALYZED BASED OFF THE 1200 UTC DAKAR SOUNDING THAT INDICATED
A MID LEVEL WIND SHIFT LATE TUES NIGHT...AND THIS POSITION IS IN
AGREEMENT WITH SURROUNDING OBS FROM THE CAPE VERDE ISLANDS
CONFIRMING THAT THE WAVE HAS NOT YET ARRIVED. THIS WAVE IS
EMBEDDED IN A SURGE OF HIGH MOISTURE S OF 18N WHICH SUPPORTS
CLUSTERS OF MODERATE CONVECTION FROM 05N TO 12N BETWEEN 16W AND
22W.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN SEA WITH AN AXIS
ALONG 72W/73W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS.
MODERATE MOISTURE IS IN THE WAVE ENVIRONMENT S OF 17N.
HOWEVER...DEEP LAYER SHEAR IS INHIBITING ANY DEEP CONVECTION WITH
THIS WAVE.

A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS ALONG
82W/83W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. THIS
WAVE IS EMBEDDED IN AN ENVIRONMENT OF MODERATE MOISTURE N OF 13N
AND HIGH MOISTURE S OF 13N. CLUSTERS OF MODERATE TO STRONG
CONVECTION ARE FROM 09N TO 13N BETWEEN 78W AND 85W. THIS
CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE OVER THIS
PORTION OF THE CARIBBEAN AND NOT SOLELY DUE TO THE PRESENCE OF
THE TROPICAL WAVE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH CROSSES OVER THE COASTAL REGIONS OF AFRICA
NEAR 11N15W AND CONTINUES OVER THE TROPICAL ATLC TO 08N25W TO
09N34W...WHERE THE ITCZ BEGINS AND CONTINUES THROUGH 07N45W TO
THE COAST OF S AMERICA NEAR 07N59W. OTHER THAN CONVECTION
ASSOCIATED WITH THE EASTERN ATLC TROPICAL WAVE...SCATTERED
MODERATE CONVECTION IS FROM 06N TO 14N BETWEEN 50W AND 60W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER LOW IS CENTERED NEAR 25N93W OVER THE WESTERN GULF.
UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER LOW AND ANOTHER UPPER
LOW OVER THE WESTERN ATLC...COMBINED WITH MODERATE
MOISTURE...SUPPORTS SCATTERED THUNDERSTORMS OVER THE NE GULF
FROM 26N TO 31N BETWEEN 83W AND 88W. A DIURNAL AND CONVECTION
FREE SURFACE TROUGH EXTENDS FROM 22N91W TO 19N91W.
OTHERWISE...GENERALLY FAIR WEATHER COVERS THE GULF BASIN DUE TO
THE PRESENCE OF DRY AIR. A NEARLY STATIONARY SURFACE HIGH OF
1021 MB CENTERED NEAR 29N85W IS A WESTERN EXTENSION OF ATLC
RIDGING WITH AN AXIS THAT EXTENDS ACROSS N FL TO LOUISIANA.
VARIABLE SURFACE WINDS OF 5 TO 10 KT ARE OVER THE NE GULF. SE
WINDS OF 10 TO 15 KT COVER THE REMAINDER OF THE GULF. OVER THE
NEXT 24 HOURS...MODERATE MOISTURE OVER THE EASTERN GULF WILL
SUPPORT SCATTERED THUNDERSTORMS. A MOISTURE INCREASE OVER THE SW
GULF IS EXPECTED AS A TROPICAL WAVE NEARS THE AREA ON THURSDAY.
THIS WILL INCREASE CHANCES FOR CONVECTION ACROSS THAT PORTION OF
THE BASIN.

CARIBBEAN SEA...

TWO TROPICAL WAVES ARE OVER THE CARIBBEAN SEA. PLEASE SEE THE
TROPICAL WAVES SECTION FOR MORE DETAILS. UPPER LEVEL DIFFLUENCE
OVER THE NW CARIBBEAN SUPPORTS SCATTERED MODERATE CONVECTION
FROM 16N TO 18N BETWEEN 83W AND 88W. THE CENTRAL AND EASTERN
CARIBBEAN UNDER STRONG SHEAR IS VOID OF DEEP CONVECTION. FRESH
TO STRONG TRADE WINDS BETWEEN HIGH PRESSURE OVER THE WESTERN
ATLC AND LOWER PRESSURE OVER S AMERICA COVER THE MAJORITY OF THE
CARIBBEAN WITH WINDS UP TO 25 KT N OF THE COAST OF
COLOMBIA...AND WINDS OF 10 KT OVER THE NW CARIBBEAN. EXPECT
ENHANCED CONVECTION TO CONTINUE OVER THE SW CARIBBEAN OVER THE
NEXT 24 HOURS WITH LITTLE CHANGE ELSEWHERE.

...HISPANIOLA...

SHALLOW MOISTURE WILL SUPPORT ISOLATED THUNDERSTORMS OVER THE
ISLAND MAINLY DURING THE AFTERNOON AND EVENING TODAY. DRY AIR
MOVING OVER THE ISLAND TONIGHT WILL FURTHER INHIBIT SHOWER AND
THUNDERSTORM ACTIVITY ON THURSDAY.

ATLANTIC OCEAN...

A SURFACE TROUGH ALONG THE SE FL COAST FROM 28N80W TO 24N81W WAS
SUPPORTING SCATTERED THUNDERSTORMS WITHIN 30 NM OF THE TROUGH
AXIS THIS MORNING. THIS FEATURE AND ASSOCIATED CONVECTION HAS
SINCE DISSIPATED. AN UPPER LOW CENTERED NEAR 25N73W SUPPORTS
SCATTERED THUNDERSTORMS FROM 23N TO 28N BETWEEN 70W AND 78W. A
1024 MB HIGH IS CENTERED NEAR 31N68W WITH AN AXIS EXTENDING
ACROSS N FL. FARTHER EAST...A STATIONARY FRONT EXTENDS INTO THE
AREA OF DISCUSSION NEAR 31N59W TO 31N47W. SCATTERED MODERATE
CONVECTION IS WITHIN 50 NM OF THE FRONT BETWEEN 53W AND 58W.
HIGH PRESSURE CENTERED N OF THE AREA OF DISCUSSION DOMINATES THE
CENTRAL AND EASTERN SUBTROPICAL ATLC. A TROPICAL WAVE IS OVER
THE FAR EASTERN ATLC. PLEASE SEE THE SPECIAL FEATURES SECTION
FOR MORE DETAILS. EXPECT THUNDERSTORMS TO CONTINUE NEAR THE
UPPER LOW FOR THE NEXT 2 DAYS AS IT SLOWLY DRIFTS SW.

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

$$
LATTO
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