[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI OCT 23 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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
17N16W TO 11N30W TO A 1012 MB LOW NEAR 11N46W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM S OF THE
TROUGH BETWEEN 19W-21W...AND ALSO WITHIN 60 NM NE QUADRANT OF
THE LOW.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE CYCLONE CENTERED NEAR 18N91W
DOMINATES THE FLOW REGIME OVER MOST OF THE GULF OF MEXICO...
AND THE WESTERN HALF OF THE CARIBBEAN. DIFFLUENT UPPER LEVEL
SOUTHWESTERLY FLOW BETWEEN THE ANTICYCLONE AND AN UPPER CYCLONE
OVER THE NORTHERN GREAT PLAINS ROCKIES IS HELPING TO SUPPORT A
FEW CLUSTERS OF SCATTERED MODERATE CONVECTION N OF ABOUT 21N AND
W OF 95W.

BUOY OBSERVATIONS FROM THE NW GULF SHOW SE WINDS OF 15-20 KT
WITH SEAS OF 8 FT. ANTICYCLONIC FLOW ON THE EASTERN PERIPHERY OF
THE ANTICYCLONE IS SPREADING HIGH LEVEL MOISTURE...IN THE FORM
OF CIRRUS CLOUDS...ACROSS MOST OF THE GULF W OF 85W WITH
GENERALLY FAIR CONDITIONS AT THE SURFACE UNDER A HIGH PRESSURE
RIDGE EXTENDING FROM THE SOUTHERN APPALACHIANS INTO THE GULF.
LIGHT TO MODERATE NE WINDS PREVAIL OVER MOST OF THE GULF E OF
90W. EXPECT THE SE 15-20 KT WINDS OVER THE NW GULF TO INCREASE
TO NEAR GALE FORCE LATE SAT INTO SUN WITH SEAS THERE TO BUILD TO
POSSIBLY 12 OR 13 FT AS A FRONTAL LOW PRESSURE MOVES EASTWARD
ALONG THE TEXAS COAST SUN AND INLAND OVER LOUISIANA BY LATE ON
MON. THE LOW AND FRONT WILL ALSO INCREASE MOISTURE ALONG WITH
SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF THE NW AND N CENTRAL
GULF LATE SAT THROUGH MON.

CARIBBEAN SEA...
THE UPPER-LEVEL ANTICYCLONE THAT DOMINATES THE GULF OF MEXICO
ALSO EXTENDS SE COVERING THE CARIBBEAN W OF 74W. TO THE E...THE
SOUTHERN PORTION OF AN UPPER-LEVEL TROUGH EXTENDS FROM THE
EASTERN PART OF HISPANIOLA S TO NEAR 10N70W. A SURFACE TROUGH IS
OVER THE FAR NW CARIBBEAN JUST E OF THE YUCATAN PENINSULA
EXTENDING FROM COZUMEL TO 18N88W TO 16N86W. ISOLATED LOW TOPPED
SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS.
ISOLATED SHOWERS AND THUNDERSTORMS ARE WITHIN 180 NM E OF THE
UPPER TROUGH N OF 15N...AND OVER AND NEAR THE WINDWARD PASSAGE.
THE EASTERN END OF THE EASTERN PACIFIC MONSOON TROUGH IS OVER
THE SW CARIBBEAN SUPPORTING SCATTERED MODERATE CONVECTION FROM
ALONG THE COASTS OF PANAMA AND COSTA RICA N TO 11N BETWEEN 76W-
81W. ISOLATED MODERATE CONVECTION IS SEEN FROM 11N-14N W OF 81W.
BUOY OBSERVATIONS AND LATEST SCATTEROMETER DATA SHOW MAINLY
MODERATE TO FRESH TRADE WINDS ACROSS THE CARIBBEAN BASIN WITH
THE STRONGEST WINDS OVER THE FAR NW CARIBBEAN N OF 18N W OF 85W
TO THE YUCATAN CHANNEL. SCATTERED MODERATE CONVECTION OVER THE
FAR SW CARIBBEAN SEA ALONG AND NEAR THE MONSOON TROUGH IS
EXPECTED TO PERSIST OVER THE NEXT 24-48 HOURS...WHILE ISOLATED
MODERATE CONVECTION CONTINUES OVER THE NE PART OF THE EASTERN
CARIBBEAN AND WATERS BETWEEN JAMAICA AND THE WINDWARD PASSAGE.

...HISPANIOLA...
A FRONTAL TROUGH JUST N OF THE N CENTRAL SECTION OF HISPANIOLA
...AND AN UPPER LEVEL TROUGH ALONG 70W IS SUPPORTING ISOLATED
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC COASTAL WATERS OF
THE DOMINICAN REPUBLIC. ISOLATED SHOWERS AND THUNDERSTORMS ARE
ALSO OVER THE WINDWARD PASSAGE AREA AND NEAR THE COAST OF HAITI.
WATER VAPOR IMAGERY SHOWS ABUNDANT MODERATE SUBSIDENCE AND
ASSOCIATED DRIER AIR FILTERING SOUTHWARD FROM THE WESTERN
ATLANTIC ACROSS HISPANIOLA AND TOWARDS THE CENTRAL CARIBBEAN
SEA. THIS WILL CONTINUE THROUGH THE NEXT 24-48 HOURS AS THE
UPPER TROUGH CONTINUES TO PUSH EASTWARD...AND WHILE BROAD UPPER-
LEVEL HIGH PRESSURE REPLACES IT. PRECIPITABLE MOISTURE GUIDANCE
FROM THE GFS SHOWS THE AXIS OF MOISTURE E OF THE UPPER TROUGH
GRADUALLY SHIFTING EASTWARD OF THE EASTERN SECTION OF THE ISLAND
INTO SUN.

ATLANTIC OCEAN...
A SHARP UPPER-LEVEL TROUGH OVER THE W ATLC STRETCHES FROM 31N70W
TO N CENTRAL HISPANIOLA. THIS TROUGH CONTINUES TO SUPPORT A COLD
FRONT THAT EXTENDS INTO THE DISCUSSION AREA FROM A 1009 MB LOW
NEAR 31N60W SW TO 30N61W WHERE IT TRANSITIONS TO A STATIONARY
FRONT TO A 1008 MB LOW NEAR 27N65W. A DISSIPATING STATIONARY
FRONT THEN EXTENDS FROM THE LOW TO 23N66W WHERE IT BECOMES A
FRONTAL TROUGH TO NEAR 19N69W. SCATTERED MODERATE CONVECTION IS
WITHIN 180 NM EITHER SIDE OF THE STATIONARY FRONT N OF 27N.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 270 NM E
OF THE DISSIPATING STATIONARY FRONT...WHILE ISOLATED MODERATE
CONVECTION IS WITHIN 300 NM E OF THE FRONTAL TROUGH. WEAKENING
ISOLATED MODERATE CONVECTION IS ALSO SEEN WITHIN 15 NM OF
29N71W. THE STATIONARY FRONT WILL WEAKEN FURTHER TO A TROUGH
OVER THE NEXT 24 HOURS AS IT SLOWLY MOVES ESE. THE 1008 MB LOW
IS FORECAST TO MOVE NE TO NEAR 30N61W WHILE DEEPENING TO 1005
MB...AND TO N OF THE AREA BY LATE SAT. SCATTERED SHOWERS AND
THUNDERSTORMS CAN BE EXPECTED WITHIN ABOUT 300 NM E OF THE
TROUGH INCLUDING THE WATERS JUST N OF PUERTO RICO OVER THE NEXT
24 HOURS. SIMILAR ACTIVITY CAN ALSO BE EXPECTED NEAR THE 1007 MB
LOW. LOW-LEVEL MOISTURE ON THE SOUTHERN PERIPHERY OF ATLANTIC
RIDGING OVER THE PORTION W OF 70W WILL ADVECT ISOLATED LOW-
TOPPED LIGHT SHOWERS AND SMALL PATCHES OF RAIN WESTWARD FROM THE
BAHAMAS TOWARDS S FLORIDA...THE FLORIDA KEYS AND STRAITS OF
FLORIDA THROUGH TONIGHT. SIMILAR SHOWER ACTIVITY..IN SMALL CLOUD
LINES...IS NOTED N AND NE OF THE BAHAMAS.

AN EASTERN ATLANTIC ELONGATED UPPER-LEVEL TROUGH SUPPORTS A 1010
MB SURFACE LOW PRESSURE CENTER NEAR 25N24W. A SURFACE TROUGH
EXTENDS FROM THE LOW SW TO 23N26W...AND NW TO 24N31W. ANOTHER
TROUGH EXTENDS FROM THE LOW NE TO NEAR 30N20W. ISOLATED SHOWERS
ARE POSSIBLE WITHIN 120 NM NE AND 75 NM N OF THE LOW. A STRONG
JET STREAM BRANCH TO THE E OF THE UPPER TROUGH IS ADVECTING
AMPLE MOISTURE TO THE NE OVER AND INLAND THE COAST OF AFRICA N
OF ABOUT 17N AND E OF 19W. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE POSSIBLE OVER THE WESTERN SAHARA PORTION OF
AFRICA...AND IN MOROCCO FROM 21N NORTHWARD BETWEEN 09W-17W.

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

$$

AGUIRRE
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