[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUN 12 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 15N51W TO 4N53W MOVING W AT 20 KT.
THE WAVE LIES WITHIN A SURGE OF DEEP LAYER MOISTURE PRESENT IN
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION
IS FROM 10N-12N BETWEEN 49W-52W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 7N-10N BETWEEN 53W-59W.

A TROPICAL WAVE EXTENDS ACROSS PANAMA FROM 14N81W TO 7N82W
MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH A MAXIMUM IN DEEP
LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER THAT RESIDES
OVER THE SW CARIBBEAN AND CONTINUES INTO THE EAST PACIFIC.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 8N-11N BETWEEN 78W-
83W. SIMILAR ACTIVITY CONTINUES UP CENTRAL AMERICA ACROSS COSTA
RICA...NICARAGUA...AND HONDURAS. THIS ACTIVITY IS ENHANCED BY AN
UPPER LEVEL TROUGH EXTENDING FROM EASTERN CUBA TO NEAR 12N83W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W
TO 8N22W. THE ITCZ BEGINS NEAR 8N22W AND CONTINUES ALONG 6N38W
8N51W 7N60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 6N-8N BETWEEN 35W-48W.

...DISCUSSION...

THE GULF OF MEXICO...
WEAK SURFACE RIDGING DOMINATES THE GULF OF MEXICO AROUND A 1021
MB HIGH NEAR 28N88W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL
RIDGE CENTERED OVER CENTRAL MEXICO NEAR 20N99W. LIGHT ANTI-
CYCLONIC WINDS ARE AROUND THE HIGH CENTER INCREASING UP TO 10-15
KT OVER THE WESTERN GULF. AN UPPER LEVEL TROUGH IS DIGGING SOUTH
OVER THE FLORIDA PENINSULA ALONG 28N80W TO 25N88W. WHILE DRY AIR
ALOFT AROUND THE NW SIDE OF THE UPPER TROUGH IS KEEPING THE NE
GULF CLEAR...DIFFLUENCE AROUND THE SE SIDE OF THE TROUGH IS
PRODUCING WIDESPREAD SHOWERS AND THUNDERSTORMS OVER THE SOUTHERN
HALF OF THE FLORIDA PENINSULA AND THE FLORIDA STRAITS. A FEW
ISOLATED SHOWERS ARE ALSO OVER THE WESTERN GULF AS MOIST AIR
WRAPS AROUND THE UPPER RIDGE OVER MEXICO. SURFACE RIDGING WILL
REMAIN THE DOMINANT FEATURE OVER THE NEXT COUPLE OF DAYS BEFORE
A WEAK FRONTAL BOUNDARY MOVES THROUGH THE NE GULF OVER THE
WEEKEND. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY OVER THE
WESTERN GULF...AND OVER SOUTHERN FLORIDA.

THE CARIBBEAN SEA...
MUCH OF THE CARIBBEAN WATERS ARE EXPERIENCING FAIR CONDITIONS
DUE TO DRY AIR ALOFT BETWEEN AN UPPER LEVEL RIDGE OVER THE
WESTERN GULF OF MEXICO...AND AN UPPER LEVEL TROUGH EXTENDING
FROM EASTERN CUBA TO NEAR 12N83W. HOWEVER...HEAVY
SHOWERS/THUNDERSTORMS ARE ACROSS JAMAICA...CUBA...AND HISPANIOLA
AS A RESULT OF DAYTIME HEATING AND INSTABILITY. A TROPICAL WAVE
MOVING THROUGH THE SW CARIBBEAN IS ALSO PRODUCING SHOWERS AND
THUNDERSTORMS S OF 12N BETWEEN 77W-83W...AND ACROSS MUCH OF
CENTRAL AMERICA. SEE TROPICAL WAVE SECTION ABOVE FOR MORE
DETAILS. CONVECTION NEAR THE WAVE IS LIKELY BEING ENHANCED BY
THE UPPER TROUGH. THE UPPER TROUGH IS PROVIDING MOIST AND
SLIGHTLY DIFFLUENT FLOW ALOFT OVER THE EASTERN CARIBBEAN...WHICH
IS LIKELY ENHANCING THE ACTIVITY OVER HISPANIOLA. A FEW ISOLATED
LOW-LEVEL SHOWERS ARE ALSO EMBEDDED IN THE 15-20 KT TRADEWIND
FLOW PRESENT THROUGHOUT THE AREA. STRONGER WINDS UP TO 25 KT ARE
NEAR THE COAST OF COLOMBIA. MOIST CONDITIONS ARE EXPECTED TO
REMAIN OVER THE SW CARIBBEAN AS THE WAVE TRACKS WESTWARD. THE
UPPER TROUGH NEAR THE MONA PASSAGE WILL LIFT NORTH AS THE UPPER
TROUGH OVER FLORIDA SINKS SOUTH AND WILL CONTINUE TO SUPPORT
SHOWER ACTIVITY OVER THE NORTHERN CARIBBEAN ISLANDS.

HISPANIOLA...
A CLUSTER OF HEAVY SHOWERS/THUNDERSTORMS IS CURRENTLY OVER HAITI
FROM 18N-20N BETWEEN 71W-73W...WHILE ISOLATED SHOWERS AND
THUNDERSTORMS DOT THE REMAINDER OF THE ISLAND. THIS ACTIVITY IS
DUE TO A COMBINATION OF DAYTIME HEATING AND INSTABILITY PRESENT
ON MOST AFTERNOONS...AND DIFFLUENT FLOW ALOFT AROUND AN UPPER
TROUGH EXTENDING FROM THE EASTERN CUBA TO THE SW CARIBBEAN.
HEAVY CONVECTION FELL IN THIS SAME AREA YESTERDAY AFTERNOON. THE
UPPER TROUGH WILL GRADUALLY LIFT NORTH OF THE NEXT 24
HOURS...BUT AN UPPER TROUGH OVER FLORIDA WILL SINK SOUTH AND
CONTINUE TO PROVIDE MOIST AND DIFFLUENT FLOW OVER THE ISLAND
INTO THE WEEKEND.

THE ATLANTIC OCEAN...
SCATTERED SHOWERS/THUNDERSTORMS ARE OVER THE FAR WESTERN ATLC
WEST OF 75W S OF 28N ASSOCIATED WITH AN ELONGATED UPPER TROUGH
DIPPING SOUTH OVER THE FLORIDA PENINSULA. A NARROW UPPER TROUGH
IS ALSO TO THE EAST ALONG 69W PROVIDING DIFFLUENT FLOW ALOFT AND
SUPPORTING ISOLATED SHOWERS FROM 24N-28N BETWEEN 62W-68W. THE
REMAINDER OF THE AREA IS DOMINATED BY ONE LARGE AND BROAD
SURFACE RIDGE ANCHORED BY A 1028 MB HIGH NEAR 30N39W.
ALOFT...UPPER RIDGING IS ALONG 56W...AND 30W...WITH AN UPPER
LEVEL TROUGH SANDWICHED BETWEEN THEM NEAR 47W. THE UPPER TROUGH
SUPPORTS AN AREA OF HIGH CLOUDS AND POSSIBLE SHOWERS FROM 20N-
27N BETWEEN 43W-48W. THE LAST VISIBLE SATELLITE IMAGES OF THE
DAY INDICATE A LARGE AREA OF SAHARAN DUST EXTENDS OFF THE COAST
OF AFRICA AND CONTINUES TO NEAR 48W.

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

$$
WALTON

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