[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU OCT 15 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...
TROPICAL WAVE EXTENDS FROM 11N26W TO 16N24W MOVING W AT 5-10 KT.
THE WAVE REMAINS LOW-AMPLITUDE AND COINCIDE WITH 700 MB
TROUGHING ALOFT BETWEEN 23W-28W. SCATTERED MODERATE CONVECTION
IS FROM 11N-15N BETWEEN 24W-27W.

TROPICAL WAVE EXTENDS FROM 11N46W TO 19N43W MOVING W AT 5-10 KT.
THE WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN 41W-48W AND
REMAINS EMBEDDED WITHIN THE ITCZ. SCATTERED MODERATE CONVECTION
IS FROM 11N-17N BETWEEN 39W-46W.

TROPICAL WAVE EXTENDS FROM 10N80W TO 19N79W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH A RELATIVELY WEAK AND SUBTLE 700 MB
TROUGH MOVING OVER THE WESTERN CARIBBEAN SEA BETWEEN 77W-83W.
SCATTERED MODERATE CONVECTION IS FROM 11N-16N BETWEEN 76W-84W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 15N20W TO 07N36W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N36W TO
12N44W TO 10N50W. ISOLATED MODERATE CONVECTION IS FROM 04N-09N
BETWEEN 04W-22W. SCATTERED MODERATE CONVECTION IS FROM 10N-18N
BETWEEN 17W-22W...AND FROM 12N-16N BETWEEN 46W-53W.

...DISCUSSION...

GULF OF MEXICO...
BROAD LONGWAVE UPPER LEVEL TROUGHING IS NOTED ON WATER VAPOR
IMAGERY OVER MUCH OF THE EASTERN CONUS AND FAR WESTERN NORTH
ATLC. THE TROUGHING SUPPORTS A STATIONARY FRONT EXTENDING FROM
27N82W WESTWARD TO BROWNSVILLE TEXAS. WHILE THE FRONT REMAINS
NEARLY PRECIPITATION-FREE AT THIS TIME...MOST MOISTURE...
CLOUDINESS...AND ISOLATED SHOWERS AND TSTMS ARE OCCURRING S OF
24N E OF 93W IN ASSOCIATION WITH MIDDLE TO UPPER LEVEL
DIFFLUENCE ON THE EASTERN PERIPHERY OF A SHORTWAVE TROUGH OVER
THE WESTERN GULF WITH AXIS ALONG 95W. NORTH OF THE FRONT...CLEAR
SKIES PREVAIL AS A 1019 MB HIGH PRESSURE ANCHORS ITSELF ACROSS
LOUISIANA. OVERALL...MODERATE E-NE WINDS PREVAIL AND ARE
EXPECTED TO INCREASE BY LATE FRIDAY AS A REINFORCING RIDGE
BUILDS SOUTHWARD ACROSS THE LOWER-MISSISSIPPI RIVER VALLEY
RESULTING IN A STRENGTHENED PRESSURE GRADIENT. STRONG E-NE WINDS
ARE FORECAST THROUGH EARLY NEXT WEEK. IN ADDITION...AS RIDGING
BUILDS SOUTHWARD ACROSS EASTERN MEXICO...NEAR GALE TO GALE FORCE
CONDITIONS ARE POSSIBLE WITHIN CLOSE PROXIMITY TO THE VERACRUZ
COAST SATURDAY THROUGH SUNDAY.

CARIBBEAN SEA...
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF
THE WESTERN CARIBBEAN AND CENTRAL AMERICA THIS AFTERNOON. WHILE
PROVIDING AN OVERALL DIFFLUENT ENVIRONMENT...TWO SPECIFIC
SURFACE FEATURES ARE PROVIDING FOCUS FOR ONGOING CONVECTION.
FIRST...A TROPICAL WAVE IS ANALYZED ALONG 79W/80W AND HAS
LARGELY BEEN CONVECTION FREE THE PAST FEW DAYS. HOWEVER...MOVING
BENEATH THE ENVELOPE OF THE UPPER LEVEL RIDGE AT THIS
TIME...SCATTERED SHOWERS AND TSTMS HAVE INCREASED IN AREAL
COVERAGE FROM 11N-16N BETWEEN 76W-84W. A FEW ISOLATED SHOWERS
AND TSTMS ARE OCCURRING NEAR THE NORTHERN EXTENT OF THE WAVE
AXIS BETWEEN JAMAICA AND THE ADJACENT COASTAL WATERS OF CUBA
WITHIN 60 NM EITHER SIDE OF A LINE FROM 18N76W TO 21N82W. THE
SECOND SURFACE FEATURE IS A SURFACE TROUGH EXTENDING FROM THE
YUCATAN CHANNEL NEAR 22N86W TO SOUTH-CENTRAL HONDURAS NEAR
14N88W. SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS ARE
OCCURRING FROM 15N-23N BETWEEN 83W-90W...INCLUDING PORTIONS OF
THE SE GULF OF MEXICO. BOTH OF THESE FEATURES ARE EXPECTED TO
CONTINUE MOVING WESTWARD AND CONTINUE BRINGING PLENTIFUL
PRECIPITATION TO CENTRAL AMERICA...SOUTHERN MEXICO...AND THE
YUCATAN PENINSULA THROUGH SATURDAY. FINALLY...E OF 75W...
RELATIVELY DRY AND STABLE NORTHERLY FLOW INFLUENCES THE EASTERN
CARIBBEAN WITH ONLY A FEW ISOLATED SHOWERS NOTED ACROSS THE
WINDWARD ISLANDS. MODERATE TO FRESH BREEZE TRADES ARE EXPECTED
TO PERSIST THROUGH WEEKEND.

...HISPANIOLA...
CURRENTLY MOSTLY CLEAR SKIES PREVAIL ACROSS THE ISLAND AS N-NW
FLOW ALOFT CONTINUES TO PROMOTE OVERALL STABLE CONDITIONS.

ATLANTIC OCEAN...
A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE EASTERN CONUS AND FAR WESTERN NORTH ATLC WATERS
SUPPORTING A COLD FRONT EXTENDING FROM 32N71W SW TO 29N78W WHERE
IT BECOMES STATIONARY TO THE FLORIDA COAST NEAR 27N80W. THE
FRONT REMAINS RELATIVELY PRECIPITATION-FREE WITH MOST OF THE
STRONGER LOW-LEVEL MOISTURE CONVERGENCE NOTED ALONG A PRE-
FRONTAL SURFACE TROUGH EXTENDING FROM 31N70W TO THE NW BAHAMAS
INTO THE FLORIDA STRAITS NEAR 24N82W. WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING N OF 21N BETWEEN 63W AND THE
SURFACE TROUGH BOUNDARY. FARTHER EAST...A SURFACE RIDGE ANCHORED
BY A 1026 MB HIGH CENTERED NEAR 35N42W CONTINUES TO PROVIDE THE
CENTRAL ATLC WITH MOSTLY FAIR CONDITIONS. A PAIR OF WEAK SURFACE
TROUGHS ARE EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF THE
RIDGING...ONE NEAR 27N46W AND THE OTHER NEAR 28N59W. FINALLY...
ACROSS THE EASTERN ATLC...A VIGOROUS MIDDLE TO UPPER LEVEL LOW
IS CENTERED NEAR 32N22W THAT SUPPORTS A PARTIALLY OCCLUDED 1000
MB LOW NEAR 32N25W. THE ASSOCIATED COLD FRONT EXTENDS FROM
32N18W TO 25N22W TO 22N30W TO 23N38W. POSSIBLE ISOLATED SHOWERS
ARE WITHIN 60 NM EITHER SIDE OF THE BOUNDARY AND N OF 28N
BETWEEN 22W-27W.

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

$$
HUFFMAN
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