[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU SEP 10 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...
TROPICAL STORM HENRI IS CENTERED NEAR 31.4N 61.0W AT 10/0900 UTC
OR ABOUT 200 NM E-SE OF BERMUDA MOVING N AT 3 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. SCATTERED MODERATE
CONVECTION IS FROM 30N-34N BETWEEN 55W-60W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N32W TO 18N29W 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 120 NM
EITHER SIDE OF THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS
FROM 12N-14N BETWEEN 29W-35W.

SURFACE TROUGHING EXTENDS FROM 12N54W TO 19N53W MOVING W AT 15-
20 KT. THE TROUGH AND ASSOCIATED 1009 MB LOW ANALYZED ALONG THE
TROUGH AXIS NEAR 15N54W...THE REMNANTS OF GRACE...REMAINS WEAK
WITH A RECENT ASCAT PASS AROUND 10/0024 UTC INDICATING THE
STRONGEST WINDS...RANGING FROM 20-25 KT...WITHIN 150 NM OF
CENTER IN THE NE QUADRANT. SCATTERED MODERATE CONVECTION IS FROM
14N-16N BETWEEN 52W-56W.

TROPICAL WAVE EXTENDS FROM 10N66W TO 17N64W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH RELATIVELY WEAK 700 MB TROUGHING BETWEEN
60W-66W WITH 850 MB RELATIVE VORTICITY MAXIMIZED FROM 10N-12N
BETWEEN 63W-70W IN THE VICINITY OF THE SOUTHERN PORTION OF THE
AXIS. WIDELY SCATTERED MODERATE CONVECTION IS FROM 12N-15N
BETWEEN 59W-68W.

TROPICAL WAVE EXTENDS FROM 10N81W TO 17N80W MOVING W AT 25 KT.
THE WAVE COINCIDES WITH SUBTLE 700 MB TROUGHING STRETCHING FROM
OVER JAMAICA ALONG THE WAVE AXIS TO OVER WESTERN PANAMA.
NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 08N-
13N BETWEEN 76W-88W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
11N24W THEN RESUMES NEAR 15N24W TO 10N32W TO 10N38W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N38W TO
08N43W TO 12N53W. SCATTERED MODERATE CONVECTION IS FROM 05N-17N
BETWEEN 10W-21W. THIS CONVECTION IS ASSOCIATED WITH THE NEXT
TROPICAL WAVE TO EMERGE OFF THE WEST AFRICAN COAST LATER TODAY.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH CONTINUES TO MOVE OVER
THE OHIO AND SOUTHERN MISSISSIPPI RIVER VALLEYS THIS MORNING
DIPPING SOUTHWARD TO A BASE OVER THE NW AND NORTH-CENTRAL GULF
WATERS. A NARROW SHEAR AXIS ALOFT EXTENDS SOUTH-SOUTHWESTWARD TO
AN UPPER LEVEL LOW CENTERED NEAR 19N95W. THE UPPER LEVEL LOW
REMAINS RELATIVELY WEAK AS TWO BROAD ANTICYCLONES INFLUENCE MUCH
OF THE GULF...ONE CENTERED OVER THE FLORIDA STRAITS NEAR 24N81W
AND THE OTHER CENTERED OVER THE SOUTHERN BAJA CALIFORNIA
PENINSULA NEAR 24N109W. GENERALLY THE ANTICYCLONIC CIRCULATIONS
ARE PROVIDING THE BASIN WITH MIDDLE TO UPPER LEVEL CLOUDINESS...
AND POSSIBLE ISOLATED SHOWERS STRETCHING FROM THE EASTERN BAY OF
CAMPECHE N-NE TO THE EASTERN GULF WATERS. OTHERWISE...SURFACE
RIDGING INFLUENCES THE GULF WITH GENTLE TO MODERATE BREEZE
CONDITIONS AROUND A 1016 MB HIGH CENTERED NEAR 26N87W. 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 18N86W AND INFLUENCES MUCH OF THE WESTERN CARIBBEAN WITH
RELATIVELY DRY NORTHERLY FLOW W OF 72W. MOST ACTIVE CONVECTION
REMAINS ACROSS PORTIONS OF CENTRAL AMERICA THIS MORNING IN
ASSOCIATION WITH TROPICAL WAVES...ONE ALONG 81W AND THE OTHER
ALONG 93W. THE TROPICAL WAVE ALONG 81W AND THE CLOSE PROXIMITY
OF THE MONSOON TROUGH AXIS IS GENERATING NUMEROUS SHOWERS AND
SCATTERED TSTMS S OF 13N BETWEEN 75W-88W. OTHERWISE...FARTHER
EAST...ANOTHER TROPICAL WAVE ALONG 65W IS PROVIDING INCREASED
MOISTURE AND CLOUDINESS FOR THE SE CARIBBEAN WITH ISOLATED
SHOWERS AND TSTMS S OF 15N E OF 68W...INCLUDING THE ABC
ISLANDS...AND PORTIONS OF THE WINDWARD ISLANDS. OTHERWISE...
MODERATE TO FRESH TRADE PREVAIL WITH SLIGHTLY STRONGER WINDS
NOTED S OF 13N BETWEEN 72W-77W OFF THE COAST OF COLOMBIA.

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

ATLANTIC OCEAN...
MOST OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF AN UPPER
LEVEL RIDGE CENTERED NEAR 24N80W OVER THE FLORIDA STRAITS. THE
RIDGING ALOFT SUPPORTS A 1016 MB HIGH CENTERED NEAR 28N74W
PROVIDING MOSTLY FAIR CONDITIONS WITH ISOLATED SHOWERS OCCURRING
WITHIN THE NW PERIPHERY FROM 30N-33N BETWEEN 76W-80W...AND FROM
26N-32N BETWEEN 66W-72W. THE LATTER IS LIKELY ASSOCIATED WITH A
MID-LEVEL SHORTWAVE TROUGH NOTED ON WATER VAPOR IMAGERY NEAR
29N71W AND THE PARENT UPPER LEVEL LOW CENTERED NEAR 35N66W.
FARTHER EAST...TROPICAL STORM HENRI IS TRACKING GENERALLY
NORTHWARD ON THE EASTERN PERIPHERY OF THE UPPER LEVEL LOW AND
WITHIN THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR
28N55W. OTHERWISE...THE REMAINDER OF THE EASTERN ATLC IS UNDER
THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A PAIR OF 1018 MB
HIGHS CENTERED NEAR 30N24W AND 25N35W. ON THE NORTHERN PERIPHERY
OF THIS RIDGING...WEAKENING FRONTAL BOUNDARY EXTENDS FROM 32N31W
INTO A 1016 MB LOW NEAR 29N36W INTO ANOTHER 1016 MB LOW CENTERED
NEAR 29N44W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90
NM EITHER SIDE OF THE BOUNDARY.

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

$$
HUFFMAN
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