[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082333
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 08 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
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 14N17W
TO 5N25W. THE ITCZ BEGINS NEAR 5N25 AND CONTINUES ALONG 4N36W
EQ42W 1S45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 4N-6N BETWEEN 23W-29W. SIMILAR ACTIVITY IS FROM EQ-4N
BETWEEN 33W-39W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE HIGH PRESSURE DOMINATES THE GULF OF MEXICO CENTERED
AROUND A 1020 MB HIGH NEAR 28N86W...AS OF 2100 UTC. THE RIDGE IS
PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE BASIN WITH CLEAR
SKIES AND LIGHT ANTI-CYCLONIC WINDS AROUND THE HIGH. ONLY A FEW
LOW LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS ARE FROM 23N-25N
BETWEEN 88W-93W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE
CURRENTLY TO THE WEST OVER TEXAS AND MEXICO. AN UPPER LEVEL
TROUGH PRESENTLY RESIDES OVER THE MAJORITY OF THE GULF WITH AXIS
EXTENDING ALONG 83W. THE RIDGE IS EXPECTED TO DOMINATE THE BASIN
THROUGHOUT THE WEEK AS IT GRADUALLY SHIFTS EAST ALLOWING RETURN
FLOW TO INCREASE ACROSS THE WESTERN GULF.

CARIBBEAN SEA...
A SURFACE TROUGH DOMINATES THE WEATHER PATTERN ACROSS THE
CARIBBEAN EXTENDING FROM SOUTH OF HAITI NEAR 18N74W TO THE COAST
OF COLOMBIA NEAR 9N76W. THE UPPER TROUGH OVER THE GULF OF MEXICO
CONTINUES INTO THE WESTERN CARIBBEAN PROVIDING DIFFLUENCE ALOFT
THAT COINCIDES WITH THE SURFACE TROUGH. THIS COMBINATION IS
PRODUCING SHOWERS AND THUNDERSTORMS WITHIN 200 NM WEST OF THE
TROUGH AXIS...AND WITHIN 90 NM EAST. STRONG SHOWERS AND
THUNDERSTORMS ARE ALSO OVER PORTIONS OF PUERTO RICO...ALL OF
HISPANIOLA...AND CENTRAL AND EASTERN CUBA. SOME OF THE ACTIVITY
NEAR HISPANIOLA IS ALSO CONNECTED TO ANOTHER SURFACE TROUGH
NORTH OF THE ISLANDS AS WELL AS A SHEAR AXIS THAT EXTENDS TO
JUST NORTH OF THE LEEWARD ISLANDS. THE FAR WESTERN AND FAR
EASTERN CARIBBEAN REMAIN MOSTLY CLEAR TO EITHER SIDE OF THE
TROUGH. TRADEWIND FLOW OF 15-20 KT IS PRESENT ACROSS THE EASTERN
CARIBBEAN BEFORE FLOWING CYCLONICALLY AROUND THE TROUGH. THE
TROUGH IS EXPECTED TO DRIFT WESTWARD WITH CONTINUED SHOWER
ACTIVITY NEAR IT. HISPANIOLA MAY BE AT RISK OF FLOODING DUE TO
THE HEAVY AMOUNTS OF RAINFALL OCCURRING CURRENTLY AND THE
POSSIBILITY OF CONTINUED SHOWER ACTIVITY OVER THE NEXT DAY OR
SO.

ATLANTIC OCEAN...
BROAD LOW PRESSURE COVERS THE FAR WEST ATLC ASSOCIATED WITH A
DEEP LAYERED TROUGH CENTERED OVER SOUTHERN PENNSYLVANIA. A
SURFACE TROUGH ENTERS THE AREA NEAR 32N75W AND EXTENDS TO
29N77W. ISOLATED SHOWERS AND THUNDERSTORMS ARE UP TO 120 NM EAST
OF THE AXIS. THE UPPER TROUGH IS ALSO PROVIDING DIFFLUENCE ALOFT
NORTH OF THE EASTERN CARIBBEAN SUPPORTING A SURFACE TROUGH ALONG
24N68W TO 20N70W ALONG WITH SCATTERED SHOWERS AND THUNDERSTORMS
WITHIN 300 NM TO EITHER SIDE OF THE AXIS. THE REMAINDER OF THE
WEST ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1031 MB HIGH
NEAR 38N56W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE
ALONG 60W. BROAD UPPER TROUGHING COVERS THE MAJORITY OF THE
EASTERN ATLC SUPPORTING A DISSIPATING COLD FRONT ALONG 32N22W
23N28W WITH ISOLATED SHOWERS UP TO 45 NM EITHER SIDE OF THE
AXIS. A SURFACE TROUGH TRAILS TO THE WEST FROM A 1016 MB LOW
NEAR 32N33W. THE TROUGH CONTINUES ALONG 31N30W 25N34W. POSSIBLE
ISOLATED SHOWERS ARE NEAR THE AXIS. A SHEAR AXIS ALSO EXTENDS
TOWARDS THE SW OF THE FRONTAL BOUNDARY ALONG 20N36W 16N51W
19N64W. ISOLATED SHOWERS ARE WITHIN 120 NM OF THE AXIS. THE
WESTERN PORTION OF THE AXIS IS ALSO CONTRIBUTING TO THE LARGE
AREA OF SHOWERS AND THUNDERSTORMS ACROSS THE NORTHERN CARIBBEAN
ISLANDS. MOIST CONDITIONS ARE EXPECTED TO REMAIN NEAR AND NORTH
OF THE EASTERN AND CENTRAL CARIBBEAN.

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

AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL SERVICES OF
HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND
FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY
BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL
WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE
DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES
ON THE ISLAND OF HISPANIOLA.

THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT
WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE
EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS
ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL.

$$
WALTON

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