[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182337
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC...

...SPECIAL FEATURE...
A SURFACE TROUGH CONTINUES TO IMPACT THE CENTRAL CARIBBEAN
ANALYZED ALONG 75W S OF 17N. SHOWERS/THUNDERSTORMS REMAIN MOSTLY
E OF THE TROUGH AFFECTING CENTRAL COLOMBIA N OF 8N BETWEEN
71W-75W ACROSS HISPANIOLA...INCLUDING HAITI. A FEW ISOLATED
SHOWERS MAY ALSO BE W OF THE TROUGH AXIS WITHIN 90 NM. TOTAL
PRECIPITABLE WATER IMAGERY INDICATES SIGNIFICANT DEEP LAYER
MOISTURE E OF THE TROUGH. THE TROUGH...ALONG WITH THE ASSOCIATED
MOISTURE...IS FORECAST TO MOVE NORTHWARD AND MERGE WITH AN
APPROACHING COLD FRONT CURRENTLY ACROSS THE WRN CARIBBEAN. THIS
MERGE SHOULD OCCUR NEAR THE WINDWARD PASSAGE IN APPROXIMATELY 12
HRS. THIS FORECAST SETS UP THE POTENTIAL FOR HEAVY RAINFALL AND
POSSIBLE FLOODING ACROSS HAITI AND THE DOMINICAN REPUBLIC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED FROM S LIBERIA NEAR 5N9W ALONG 6N15W
1N35W 2N44W TO THE NE BRAZIL COAST NEAR 1N53W. ISOLATED MODERATE
CONVECTION IS FROM 2N-6N BETWEEN 13W-17W. SIMILAR ACTIVITY IS
FROM 1N-3N BETWEEN 28W-36W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE HIGH PRESSURE DOMINATES THE WRN GULF OF MEXICO ANCHORED
BY A PAIR OF 1022 MB HIGHS CENTERED E OF TAMPICO MEXICO NEAR
22N96W...AND OVER E TEXAS NEAR 32N96W. THE SURFACE RIDGING ALONG
WITH DRY AIR ALOFT IS PROVIDING GENERALLY FAIR WEATHER OVER THE
BASIN W OF 87W. A DEEP LAYERED TROUGH COVERS THE ERN PORTION OF
THE BASIN CENTERED AROUND AN UPPER LEVEL LOW OVER S CAROLINA
NEAR 35N80W. THE UPPER LEVEL TROUGH IS SUPPORTING A SURFACE LOW
PRESSURE SYSTEM AND A COLD FRONT OVER THE W ATLC. HOWEVER...A
SECOND SURGE OF ENERGY ASSOCIATED WITH THIS UPPER LEVEL TROUGH
IS SUPPORTING A SURFACE TROUGH EXTENDING FROM JUST W OF S
FLORIDA NEAR 25N82W TO 23N88W. SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS ARE WITHIN 120 NM N OF THE AXIS E OF 86W...AND
WITHIN 75 NM S OF THE AXIS E OF 87W. EXPECT THE SURFACE RIDGE TO
SHIFT EWD AND REMAIN OVER THE ERN GULF OF MEXICO FOR THE NEXT
COUPLE OF DAYS BEFORE A COLD FRONT MOVES OFF THE TEXAS COAST
LATE SAT.

THE CARIBBEAN SEA...
A COLD FRONT EXTENDS FROM THE W ATLC ACROSS ERN CUBA NEAR 21N76W
TO NW OF JAMAICA NEAR 18N79W CONTINUING SW TO THE
HONDURAS/NICARAGUA BORDER NEAR 15N83W TO 15N88W. ISOLATED
SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE AXIS N OF 16N...AND
WITHIN 75 NM OF THE AXIS WITH POSSIBLE THUNDERSTORMS S OF 16N. A
DEEP LAYER TROUGH ANCHORED BY AN UPPER LEVEL LOW OVER S CAROLINA
WITH AXIS DOWN THE W COAST OF FLORIDA INTO THE NW CARIBBEAN
SUPPORTS THE FRONT. UPPER LEVEL SWLY FLOW BETWEEN THIS UPPER
TROUGH AND AN UPPER LEVEL RIDGE TO THE E OF THE ANTILLES IS
DRAWING MOISTURE ACROSS THE CENTRAL CARIBBEAN ENHANCING SHOWER
ACTIVITY NEAR A SURFACE TROUGH ALONG 75W. SEE SPECIAL FEATURES
ABOVE. FARTHER E...MODERATE TRADEWINDS PREVAIL ALONG WITH
GENERALLY FAIR WEATHER. EXPECT MOISTURE ASSOCIATED WITH THE COLD
FRONT AND THE TROUGH TO MERGE OVER THE NEXT 12 HOURS SETTING UP
THE POTENTIAL FOR HEAVY RAINFALL OVER THE WINDWARD PASSAGE AND
HISPANIOLA.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH CENTERED OVER S CAROLINA DOMINATES THE W
ATLC SUPPORTING AN OCCLUDED 1005 MB SURFACE LOW NEAR 32N75W. A
COLD FRONT ENTERS THE DISCUSSION AREA NEAR 31N72W ALONG 26N72W
ACROSS THE SE BAHAMAS NEAR 22N74W TO ERN CUBA AND INTO THE
CARIBBEAN. SCATTERED SHOWERS ARE E OF THE FRONT N OF 22N BETWEEN
61W-68W. ACROSS THE CENTRAL ATLC...A SURFACE RIDGE IS ANCHORED
BY A 1019 MB HIGH NEAR 25N55W. THE HIGH IS SUPPORTED BY AN UPPER
LEVEL RIDGE ALONG 50W. HOWEVER...A FRONTAL BOUNDARY PROTRUDES
INTO THE SURFACE RIDGE FROM THE E. THE COLD FRONT ENTERS THE
DISCUSSION AREA NEAR 32N25W CONTINUING ALONG 25N34W 22N45W TO
NEAR 20N53W WHERE IT BECOMES STATIONARY TO 20N61W. SCATTERED
SHOWERS ARE WITHIN 60 NM OF THE AXIS. THIS FRONT IS SUPPORTED BY
AN UPPER LEVEL TROUGH EXTENDING FROM THE AZORES ISLANDS TO THE
CANARY ISLANDS.

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

$$
WALTON



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