[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
TROPICAL STORM HENRI IS CENTERED NEAR 31.1N 60.7W AT 10/0300 UTC
OR ABOUT 215 NM E-SE OF BERMUDA MOVING N AT 4 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-33N BETWEEN 56W-60W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N30W TO 18N28W 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. NO SIGNIFICANT DEEP CONVECTION IS
OCCURRING WITH THE WAVE AT THIS TIME.

SURFACE TROUGHING EXTENDS FROM 13N53W TO 18N51W MOVING W AT 15-
20 KT. THE TROUGH...REMNANTS OF GRACE...CONTINUES TO SHOW A WEAK
1011 MB LOW CENTERED NEAR 14.5N52W PER A RECENT ASCAT PASS
AROUND 10/0024 UTC WITH 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 51W-55W.

TROPICAL WAVE EXTENDS FROM 09N62W TO 15N61W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH RELATIVELY WEAK 700 MB TROUGHING
BETWEEN 60W-66W WITH 850 MB RELATIVE VORTICITY MAXIMIZED FROM
10N-12N BETWEEN 60W-68W IN THE VICINITY OF THE SOUTHERN PORTION
OF THE AXIS. ISOLATED MODERATE CONVECTION IS FROM 11N-14N
BETWEEN 58W-67W.

TROPICAL WAVE EXTENDS FROM 06N80W TO 17N76W MOVING W AT 25 KT.
THE WAVE COINCIDES WITH SUBTLE 700 MB TROUGHING STRETCHING FROM
OVER THE WINDWARD PASSAGE REGION ALONG THE WAVE AXIS TO OVER THE
GULF OF PANAMA. NUMEROUS MODERATE AND SCATTERED STRONG
CONVECTION IS FROM 05N-11N BETWEEN 80W-87W. SCATTERED MODERATE
IS ALSO FROM 05N-09N BETWEEN 75W-78W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO
10N30W TO 10N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 10N40W TO 13N52W TO 12N61W. NUMEROUS MODERATE AND
SCATTERED STRONG CONVECTION IS FROM 11N-16N BETWEEN 11W-17W...
WITH WIDELY SCATTERED MODERATE CONVECTION ELSEWHERE FROM 05N-11N
BETWEEN 08W-17W. THIS CONVECTION IS LIKELY THE NEXT TROPICAL
WAVE TO EMERGE OFF THE WEST AFRICAN COAST LATER THIS MORNING.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH CONTINUES TO MOVE OVER
THE OHIO AND SOUTHERN MISSISSIPPI RIVER VALLEYS THIS EVENING
DIPPING SOUTHWARD TO A BASE OVER THE NW GULF WATERS NEAR 28N93W.
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 NEAR 26N86W. OTHERWISE...SURFACE RIDGING
INFLUENCES THE GULF WITH GENTLE TO MODERATE BREEZE CONDITIONS
AROUND A 1015 MB HIGH CENTERED WEST OF THE TAMPA BAY REGION NEAR
27N84W. THE RIDGING IS FORECAST TO HOLD IN PLACE UNTIL LATE
FRIDAY INTO SATURDAY WHEN 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 23N82W 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 EVENING IN
ASSOCIATION WITH TROPICAL WAVES...ONE ALONG 79W AND THE OTHER
ALONG 91W. THE TROPICAL WAVE ALONG 79W AND THE CLOSE PROXIMITY
OF THE MONSOON TROUGH AXIS IS GENERATING NUMEROUS SHOWERS AND
SCATTERED TSTMS S OF 11N BETWEEN 76W-87W. OTHERWISE...FARTHER
EAST...ANOTHER TROPICAL WAVE ALONG 62W IS PROVIDING INCREASED
MOISTURE AND CLOUDINESS FOR THE SE CARIBBEAN WITH ISOLATED
SHOWERS AND TSTMS S OF 14N E OF 69W...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 FOR THE OVERNIGHT
PERIOD INTO THURSDAY MORNING.

ATLANTIC OCEAN...
MOST OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF AN UPPER
LEVEL RIDGE CENTERED NEAR 23N82W OVER THE FLORIDA STRAITS. THE
RIDGING ALOFT SUPPORTS A 1016 MB HIGH CENTERED NEAR 29N75W
PROVIDING MOSTLY FAIR CONDITIONS WITH ISOLATED SHOWERS OCCURRING
WITHIN THE NW PERIPHERY FROM 27N-32N BETWEEN 67W-74W. THIS IS
LIKELY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH NOTED ON
WATER VAPOR IMAGERY NEAR 30N72W AND THE PARENT UPPER LEVEL LOW
CENTERED NEAR 35N67W. 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 1019 MB HIGH CENTERED NEAR 30N23W AND A 1018 MB
HIGH CENTERED NEAR 26N41W. ON THE NORTHERN PERIPHERY OF THIS
RIDGING...A WEAKENING FRONTAL BOUNDARY EXTENDS FROM 33N20W TO
24N27W TO 30N35W TO 29N47W. 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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