[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI SEP 11 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...
TROPICAL STORM HENRI IS CENTERED NEAR 34.8N 60.7W AT 11/0300 UTC
OR ABOUT 250 NM NE OF BERMUDA AND ABOUT 790 SSW OF CAPE RACE
NEWFOUNDLAND MOVING N AT 12 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH
GUSTS TO 45 KT. ISOLATED MODERATE CONVECTION IS FROM 34N-39N
BETWEEN 57W-61W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/
WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 08N15W TO 16N16W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH RELATIVELY BROAD 700 MB TROUGHING
BETWEEN 13W-22W WITH MAXIMUM 850 MB RELATIVE VORTICITY FROM 08N-
12N BETWEEN 14W-21W. FAIRLY DISORGANIZED ISOLATED MODERATE
CONVECTION ACCOMPANIES THE WAVE FROM 07N-14N BETWEEN 11W-22W.

TROPICAL WAVE EXTENDS FROM 09N37W TO 18N33W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A RELATIVELY SHARP 700 MB TROUGH AND A
MAXIMUM IN 850 MB RELATIVE VORTICITY STRETCHED WITHIN 90 NM
EITHER SIDE OF THE WAVE AXIS. NO SIGNIFICANT CONVECTION IS
OCCURRING WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 13N60W TO 19N59W MOVING W AT 15-20
KT. THE WAVE...THE REMNANTS OF GRACE...REMAINS WEAK WITH A
RECENT ASCAT PASS AROUND 11/0050 UTC INDICATING A SHARP TROUGH
AXIS WITH NO CLOSED CIRCULATION AT THIS TIME. THE STRONGEST
WINDS...RANGING FROM 20-30 KT...ARE FOUND FROM 17N-19N BETWEEN
58W-62W. SCATTERED MODERATE CONVECTION IS FROM 16N-20N BETWEEN
57W-62W.

TROPICAL WAVE EXTENDS FROM 10N87W TO 17N86W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH RELATIVELY WEAK 700 MB TROUGHING LARGELY
LOCATED IN THE EAST PACIFIC REGION WITH 850 MB RELATIVE
VORTICITY MAXIMIZED WEST OF COSTA RICA IN THE VICINITY OF
10N87W. ISOLATED MODERATE CONVECTION IS OCCURRING ACROSS
PORTIONS OF CENTRAL AMERICA FROM WESTERN PANAMA N-NW TO HONDURAS
AND EL SALVADOR WITH THIS WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N16W TO
09N22W TO 10N35W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 10N35W TO 08N46W TO 08N58W. ISOLATED MODERATE
CONVECTION IS FROM 06N-10N BETWEEN 18W-35W. SCATTERED MODERATE
CONVECTION IS FROM 07N-12N BETWEEN 39W-55W.

...DISCUSSION...

GULF OF MEXICO...
BROAD LONGWAVE MIDDLE TO UPPER LEVEL TROUGHING LIES OVER A LARGE
PORTION OF THE CONUS WITH UPPER LEVEL TROUGHING DIPPING
SOUTHWARD OVER THE NORTHERN GULF N OF 25N. THE ASSOCIATED
FRONTAL BOUNDARY LIES ACROSS THE SE CONUS FROM THE CENTRAL
CAROLINAS W-SW TO EASTERN TEXAS. MIDDLE TO UPPER LEVEL MOISTURE
IS PLENTIFUL ACROSS THE BASIN WITH ISOLATED SHOWERS AND TSTMS
OCCURRING IN A ZONE OF MAXIMUM DIFFLUENCE FROM 25N-29N BETWEEN
90W-99W. OTHERWISE...SURFACE RIDGING INFLUENCES THE GULF WITH
GENTLE TO MODERATE BREEZE CONDITIONS AROUND A 1016 MB HIGH
CENTERED NEAR 28N89W. THE RIDGING IS FORECAST TO HOLD IN PLACE
THROUGH LATE FRIDAY INTO SATURDAY WHEN THEREAFTER WEAK SURFACE
TROUGHING IS EXPECTED TO EXTEND ALONG THE GULF COAST FROM THE
FLORIDA BIG BEND TO NEAR GALVESTON BAY.

CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
NEAR 18N87W AND INFLUENCES MUCH OF THE WESTERN CARIBBEAN WITH
RELATIVELY DRY NORTHERLY FLOW W OF 72W. MOST ACTIVE CONVECTION
REMAINS ACROSS PORTIONS OF CENTRAL AMERICA AND THE SW CARIBBEAN
THIS EVENING IN ASSOCIATION WITH A TROPICAL WAVE ALONG 87W AND
THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 11N.
ISOLATED SHOWERS AND TSTMS GENERALLY REMAIN S OF 12N BETWEEN
NORTHERN COLOMBIA AND WESTERN NICARAGUA. OTHERWISE...FARTHER
EAST...ANOTHER TROPICAL WAVE ALONG 60W...THE REMNANTS OF
GRACE...IS PROVIDING INCREASED MOISTURE AND CLOUDINESS FOR THE
LEEWARD ISLANDS AND AREAS TO THE IMMEDIATE NE. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING FROM 15N-20N BETWEEN 58W-62W.

...HISPANIOLA...
CURRENTLY MOSTLY CLEAR SKIES PREVAIL WITH DRY NORTHERLY FLOW
ALOFT PROVIDING OVERALL STABLE CONDITIONS THIS EVENING.

ATLANTIC OCEAN...
MOST OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF AN UPPER
LEVEL RIDGE AXIS EXTENDING FROM OVER CUBA NE TO BEYOND 33N70W.
NORTH OF THE AXIS...SOUTHWESTERLY FLOW ALOFT PREVAILS EAST OF
BROAD UPPER LEVEL TROUGHING OVER THE EASTERN CONUS. THE
ASSOCIATED FRONTAL BOUNDARY EXTENDS FROM THE DELMARVA REGION SW
TO EASTERN TEXAS...HOWEVER PRE-FRONTAL MOISTURE CONVERGENCE IS
SUPPORTING ISOLATED SHOWERS AND TSTMS OFF THE COAST OF THE
FLORIDA PENINSULA AND OFF THE COAST OF THE CAROLINAS THIS
EVENING. OTHERWISE...SURFACE RIDGING EXTENDS FROM A 1019 MB HIGH
CENTERED NEAR 26N58W TO THE NORTH-CENTRAL GULF OF MEXICO WITH
ONLY ISOLATED SHOWERS OCCURRING IN THE VICINITY OF 26N65W IN
ASSOCIATION WITH A BROAD UPPER LEVEL TROUGH INFLUENCING THE AREA
N OF 20N BETWEEN 60W-70W. OTHERWISE...THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE
RIDGING ANCHORED BY THE 1019 MB HIGH PREVIOUSLY MENTIONED AND A
1021 MB HIGH CENTERED NEAR 29N26W. WEST OF THIS HIGH...A SURFACE
TROUGH EXTENDS FROM 32N28W TO 27N38W WITH POSSIBLE ISOLATED
SHOWERS OCCURRING WITHIN 120 NM EITHER SIDE OF THE BOUNDARY.

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

$$
HUFFMAN


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