[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131718
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE APR 13 2010

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1645 UTC...

...THE ITCZ...
THE ITCZ AXIS IS CENTERED FROM LIBERIA NEAR 6N9W ALONG 3N20W
2N30W 3N40W INTO NE SOUTH AMERICA NEAR 5N52W. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 1N-5N BETWEEN 12W-19W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM EQ-5N
BETWEEN 20W-28W. SIMILAR ACTIVITY IS FROM 1N-3N BETWEEN
32W-37W...AND FROM 4N-6N BETWEEN 38W-45W. ISOLATED
MODERATE/STRONG IS FROM EQ-10N BETWEEN 46W-57W.

DISCUSSION...

THE GULF OF MEXICO...
A SURFACE TROUGH LINES THE MEXICO COAST IN THE WRN BAY OF
CAMPECHE ALONG 23N96W TO 18N94W. AN UPPER LEVEL SHORTWAVE TROUGH
EXTENDING FROM LOUISIANA TO ERN MEXICO IS SUPPORTING THE SURFACE
TROUGH AS WELL A LARGE AREA OF SHOWER ACTIVITY. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS COVER THE BAY OF CAMPECHE AND THE
SRN PORTION OF TEXAS S OF 28N W OF 89W. THE MAJORITY OF THE
THUNDERSTORMS ARE CONCENTRATED NEAR THE SURFACE TROUGH. A
SURFACE RIDGE BUILDS ACROSS THE ERN AND NRN GULF PROVIDING
GENERALLY FAIR WEATHER ACROSS MUCH OF THE GULF COAST STATES.
HOWEVER...WINDS UP TO 20 KT ARE IMPACTING MUCH OF THE BASIN
AROUND THE RIDGE. ALOFT...SIGNIFICANT DRY AIR IS NOTED IN WATER
IMAGERY ACROSS THE NE GULF AND MUCH OF THE FLORIDA PENINSULA
SUPPORTING CLEAR SKIES. BESIDES THE SHORTWAVE UPPER TROUGH
ACROSS THE WRN GULF...MAINLY ZONAL FLOW COVERS THE REMAINDER OF
THE AREA. EXPECT THE SURFACE RIDGE TO REMAIN IN PLACE OVER THE
NEXT SEVERAL DAYS.

THE CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER
TODAY ASSOCIATED WITH MODERATELY DRY AIR ALOFT IN UPPER LEVEL
WLY FLOW. A FEW ISOLATED SHOWERS ARE NOTED S OF HAITI FROM
16N-18N BETWEEN 73W-76W...AND WITHIN 60 NM OF THE COSTA RICA AND
PANAMA COAST. A SURFACE TROUGH EXTENDS FROM THE ATLC ACROSS THE
MONA PASSAGE ALONG 21N66W TO 17N68W. MOST OF THE SHOWER ACTIVITY
IS NORTH OF THE CARIBBEAN ISLANDS. HOWEVER...ISOLATED SHOWERS
STILL REMAIN WITHIN 90 NM EITHER SIDE OF THE AXIS ACROSS
PORTIONS OF HISPANIOLA AND PUERTO RICO. A SURFACE TROUGH E OF
THE LESSER ANTILLES IS PRODUCING SCATTERED SHOWERS WHICH ARE NOW
AFFECTING THE LEEWARD ISLANDS. A WEAK PRESSURE GRADIENT IS
PROVIDING MODERATE TRADEWINDS ACROSS MUCH OF THE BASIN. EXPECT
THE SURFACE TROUGH ACROSS THE MONA PASSAGE TO DRIFT NE...WHILE
MOISTURE ASSOCIATED WITH THE SURFACE TROUGH E OF THE ANTILLES
WILL CONTINUE TO IMPACT THE LEEWARD ISLANDS.

THE ATLANTIC OCEAN...
A DYING STATIONARY FRONT CONTINUES TO IMPACT THE FAR WRN ATLC
ENTERING THE DISCUSSION AREA NEAR 32N62W 28N65W 27N70W WHERE IT
CONTINUES AS A SURFACE TROUGH TO THE CENTRAL BAHAMAS NEAR
26N76W. AN UPPER LEVEL TROUGH EXTENDING ACROSS THE NWRN ATLC
ALONG 68W NARROWS AND CONTINUES TO THE NW BAHAMAS SUPPORTING THE
FRONTAL BOUNDARY AND PROVIDES DIFFLUENCE ALOFT SUPPORTING A
LARGE AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NEAR THE
FRONT FROM 23N-31N BETWEEN 60W-73W. ISOLATED SHOWERS ARE S OF
THIS AREA FROM 20N-23N BETWEEN 62W-73W. SOME OF THIS SHOWER
ACTIVITY IS FURTHER ENHANCED BY A SURFACE TROUGH EXTENDING
ACROSS MONA PASSAGE FROM 21N66W TO 17N68W. A SECOND SURFACE
TROUGH EXTENDS E OF THE LEEWARD ISLANDS FROM 14N60W TO 18N60W
SUPPORTING SCATTERED SHOWERS FROM 15N-19N BETWEEN 55W-62W. TOTAL
PRECIPITABLE WATER IMAGERY ALSO INDICATES SIGNIFICANT LOW-LEVEL
MOISTURE ASSOCIATED WITH THIS TROUGH. ACROSS THE CENTRAL
ATLC...A BROAD SURFACE RIDGE BUILDS FROM A 1035 MB HIGH NEAR
50N40W PROVIDING GENERALLY FAIR WEATHER ACROSS THIS AREA.
FARTHER E...A DYING COLD FRONT EXTENDS FROM A 1002 MB LOW OFF
THE COAST OF PORTUGAL CROSSING THE CANARY ISLANDS NEAR 28N15W
CONTINUING ALONG 24N21W 22N32W. A PAIR OF SURFACE TROUGHS EXTEND
BEHIND THE FRONT ASSOCIATED WITH A 999 MB LOW NEAR 33N23W. THE
FIRST TROUGH EXTENDS ALONG 30N19W 27N23W 25N32W. THE SECOND
TROUGH EXTENDS ALONG 31N22W 28N26W 28N33W. ISOLATED SHOWERS ARE
POSSIBLE WITHIN 30 NM EITHER SIDE OF EACH OF THESE BOUNDARIES.
THE ENTIRE SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH
EXTENDING FROM 43N14W TO 26N34W.

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

$$

WALTON/RAMOS





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