[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160605 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 16 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
0545 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE E ATLC ASSOCIATED WITH A 1012 MB LOW
NEAR 10N24W THAT MOVES W AT 10-15 KT. CIRA LAYER PRECIPITABLE
WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE WAVE IS
ASSOCIATED WITH A BROAD AREA OF MAINLY MODERATE MOISTURE THAT
ALONG WITH A DIFFLUENT WIND ENVIRONMENT ALOFT SUPPORT SCATTERED
MODERATE CONVECTION FROM 07N TO 12N BETWEEN 22W AND 28W. SAHARAN
DRY AIR AND DUST ARE N OF THE LOW...THUS SUPPRESSING CONVECTION.

A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS NEAR 42W
...MOVING W AT 10 KT OVER THE PAST 24 HOURS. CIRA LAYER
PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE
WAVE IS WITHIN A MODERATE MOIST ENVIRONMENT. HOWEVER...ENHANCED
METEOSAT IMAGERY SHOW SAHARAN DRY AIR AND DUST COVERING MOST OF
THE WAVE...THUS LIMITING THE CONVECTION TO ISOLATED SHOWERS AND
TSTMS FROM 06N TO 11N BETWEEN 40W AND 45W.

A TROPICAL WAVE IS IN THE CARIBBEAN WITH AXIS NEAR 68W...MOVING
W AT 15-20 KT OVER THE PAST 24 HOURS. THE WAVE IS ASSOCIATED
WITH A MODERATE MOIST ENVIRONMENT FROM THE SURFACE TO 850 MB
ACCORDING TO CIRA LAYER PRECIPITABLE WATER IMAGERY. A DIFFLUENT
WIND ENVIRONMENT AT THE UPPER LEVELS IN THE NE CARIBBEAN AND
ADJACENT ATLC WATERS ALONG WITH THE MOISTURE SUPPORT SCATTERED
TO ISOLATED SHOWERS OVER PUERTO RICO...VIRGIN ISLANDS AND
NORTHERN LEEWARD ISLANDS. STRONG DEEP LAYER WIND SHEAR HINDER
CONVECTION ACROSS THE E-SE CARIBBEAN BASIN.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 19N16W TO
A 1012 MB LOW NEAR 10N24W TO 07N37W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 07N37W TO 08N42W...THEN
RESUMES W OF A TROPICAL WAVE NEAR 07N44W TO THE COAST OF SURINAME
NEAR 05N54W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE NEAR THE CAPE VERDE ISLANDS...SCATTERED MODERATE CONVECTION
IS FROM 07N-10N E OF 19W AND FROM 05N TO 08N BETWEEN 47W AND 52W.

...DISCUSSION...

GULF OF MEXICO...

AN ELONGATED UPPER TROUGH EXTENDS FROM THE NE CONUS SW TO
TENNESSEE TO A BASE OVER THE NW GULF...THUS SUPPORTING A 1012 MB
LOW NEAR 25N94W FROM WHICH A SURFACE TROUGH EXTENDS N-NE TO
24N91W TO MISSISSIPPI COASTAL WATERS NEAR 30N88W. SOUTHWESTERLY
WIND FLOW AROUND THE NW PERIPHERY OF AN UPPER RIDGE CENTERED
OVER THE CARIBBEAN AND SOUTHERLY WIND FLOW OVER THE CENTRAL GULF
GENERATE A DIFFLUENT WIND ENVIRONMENT E OF 92W...WHICH ALONG
WITH SHALLOW MOISTURE ADVECTING FROM THE CARIBBEAN SUPPORT
SCATTERED SHOWERS AND TSTMS FROM 22N TO 30N BETWEEN 82W AND 92W.
BROAD SURFACE HIGH PRESSURE OVER THE ATLC EXTENDS A RIDGE AXIS
SW ACROSS THE FLORIDA PENINSULA TO E OF 89W AND PROVIDES MAINLY
SE TO E WIND FLOW OF LESS THAN 15 KT ACROSS THE GULF. THE LOW
PRESSURE CENTER IS FORECAST TO DISSIPATE BY TOMORROW NIGHT
LEAVING JUST A TROUGH OF LOW PRESSURE ALONG THE NW BASIN.
RIDGING WILL BE THE DOMINANT FEATURE ELSEWHERE.

CARIBBEAN SEA...

A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR
12N68W AND COVERS THE BASIN TONIGHT. EVEN THAT SHALLOW MOISTURE
DOMINATES ACROSS THE BASIN...DRY AIR SUBSIDENCE FROM ALOFT ALONG
WITH STRONG DEEP LAYER WIND SHEAR PROVIDE STABILITY...SUPPORTING
MAINLY FAIR WEATHER BASIN-WIDE. SCATTERED SHOWERS AND TSTMS ARE
OVER THE NE CARIBBEAN ASSOCIATED WITH A TROPICAL WAVE WITH AXIS
CURRENTLY MOVING OVER THE MONA PASSAGE TOWARDS HISPANIOLA.
SIMILAR CONVECTION IS OVER THE SW BASIN S OF 11N BETWEEN
NORTHERN COLOMBIA AND COSTA RICA BEING ENHANCED BY THE EPAC
MONSOON TROUGH. NE TO E WINDS OF 20 TO 25 KT ARE FROM 11N TO
13.5N BETWEEN 70W AND 76W WITH SEAS TO 9 FT. THESE CONDITIONS
ARE EXPECTED TO PREVAIL IN THIS REGION FOR THE NEXT TWO DAYS.
THE WAVE WILL MOVE ACROSS THE CENTRAL BASIN SUNDAY THROUGH
MONDAY ENHANCING SHOWERS ACROSS HISPANIOLA AND ADJACENT WATERS.

...HISPANIOLA...

CLOUDY SKIES WITH POSSIBLE ISOLATED SHOWERS COVER THE
ISLAND...HOWEVER CONVECTIVE ACTIVITY IS EXPECTED TO INCREASE
DURING THE NEXT 24 TO 36 HOURS WITH THE APPROACH OF A TROPICAL
WAVE IMPACTING PUERTO RICO THIS MORNING. THE INCREASED
PROBABILITY OF PRECIPITATION...LOCALLY HEAVY AT TIMES ON
SUNDAY...WILL INCREASE THE RISK OF FLASH FLOODING AND MUDSLIDES
THROUGH THROUGH MONDAY.

ATLANTIC OCEAN...

AN UPPER LEVEL LOW IS NEAR 30N60W AND EXTENDS A TROUGH SW TO A
BASE E-NE OF THE SOUTHERN BAHAMAS. THIS IS SUPPORTING A 1018 MB
LOW NEAR 29N57W FROM WHICH A SURFACE TROUGH EXTENDS SW TO
26N64W. ISOLATED SHOWERS ARE POSSIBLE IN THE VICINITY OF THE
LOW. SCATTERED SHOWERS ARE S OF 23N BETWEEN 60W AND 68W
ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE ACROSS THE EASTERN
CARIBBEAN. A BROAD SURFACE RIDGE COVERS THE REMAINDER BASIN AND
SUPPORTS FAIR WEATHER. FOR TROPICAL WAVES SEE SECTION ABOVE.

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

$$
NR
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