[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182347
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 18 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.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N53W TO 5N56W MOVING W AT 15 KT.
THE WAVE REMAINS LOW-AMPLITUDE AND HAS BROKEN AWAY FROM THE
INFLUENCE OF THE ITCZ AXIS WHICH IS LOCATED TO THE SE. THE WAVE
COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE WATER IMAGERY
THAT EXTENDS NORTHWARD TO NEAR 13N. ISOLATED MODERATE CONVECTION
IS BOTH EAST AND WEST OF THE WAVE FROM 5N-11N BETWEEN 47W-
55W...AND FROM 7N-11N BETWEEN 55W-59W. THIS CONVECTION IS LIKELY
ENHANCED DUE TO UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE
WESTERN PERIPHERY OF AN UPPER LEVEL RIDGE OVER THE TROPICAL ATLC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 10N13W
TO 5N18W. THE ITCZ BEGINS AT 5N18W AND CONTINUES ALONG 3N28W
1N36W EQ46W 1S49W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 3N-5N BETWEEN 18W020W...AND FROM 2N-5N BETWEEN 27W-33W.

...DISCUSSION...

GULF OF MEXICO...
FAIR WEATHER CONTINUES TO BE PRESENT THROUGHOUT THE GULF OF
MEXICO THIS EVENING. SURFACE RIDGING EXTENDS FROM THE WEST ATLC
WITH AXIS FROM THE NE GULF TO SW GULF. THIS PATTERN SUPPORTS
EAST TO SOUTHEAST WINDS RANGING FROM 5-10 KT IN THE EASTERN GULF
TO 15-20 KT IN THE WESTERN GULF ESPECIALLY NEAR THE COAST OF
TEXAS. THE RIDGE IS SUPPORTED ALOFT BY AN UPPER LEVEL RIDGE
ALONG 93W. WATER VAPOR IMAGERY INDICATES DRY AIR COVERS MUCH OF
THE BASIN EXCEPT FOR THE NW CORNER WHERE HIGH CLOUDS ARE ALSO
PRESENT. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW AN AREA OF
SMOKE ACROSS THE SW GULF DUE TO FIRES OVER SOUTHERN MEXICO. A
FEW CLUSTERS OF THUNDERSTORMS HAVE ALSO POPPED UP DOWN THE
FLORIDA PENINSULA MOSTLY IN SOUTH FLORIDA AND THE NE CORNER OF
THE STATE. LITTLE CHANGE IS EXPECTED OVER THE NEXT COUPLE OF
DAYS.

CARIBBEAN SEA...
DRY AND STABLE AIR COVERS THE MAJORITY OF THE CARIBBEAN IN
WESTERLY FLOW ALOFT. THE DRY AIR IS HELPING MAINTAIN GENERALLY
FAIR WEATHER ACROSS THE BASIN. HOWEVER...AFTERNOON SHOWERS AND
THUNDERSTORMS HAVE POPPED UP ACROSS MANY OF THE NORTHERN
CARIBBEAN ISLANDS INCLUDING CUBA...JAMAICA...AND HISPANIOLA. A
FEW ISOLATED SHOWERS ARE ALSO MOVING THROUGH THE NW CORNER OF
THE BASIN INTO THE YUCATAN CHANNEL. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO IN THE FAR SW CORNER AND OVER
COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH THAT
EXTENDS FROM THE E PACIFIC THROUGH BOTH CONTINUE AND INTO
COLOMBIA. TRADEWIND FLOW OF 15-20 KT DOMINATES THROUGHOUT.
LITTLE CHANGE IS EXPECTED EXCEPT FOR AN INCREASE IN MOISTURE
ACROSS THE WINDWARD ISLANDS AS A TROPICAL WAVE APPROACHED FROM
THE EAST.

HISPANIOLA...
CURRENTLY AFTERNOON SHOWERS AND THUNDERSTORMS ARE BEGINNING TO
DIE DOWN AFTER PEAKING AROUND 2100 UTC. SCATTERED
SHOWERS/THUNDERSTORMS ARE STILL PRESENT THROUGHOUT THE ISLANDS
MAINLY CENTERED IN THE CENTRAL PORTIONS. THIS ACTIVITY WILL
LIKELY CONTINUE TO DIE DOWN OVER THE NEXT COUPLE OF HOURS. MODEL
GUIDANCE INDICATES A SIMILAR PATTERN WILL PERSIST OVER THE NEXT
COUPLE OF DAYS WITH THE MOST LIKELY PRECIPITATION TO BE DURING
THE AFTERNOON AND EARLY EVENING HOURS ACROSS THE ISLAND WHEN
PEAK DAYTIME HEATING AND INSTABILITY OCCUR. ANY AREAS THAT
RECEIVE MEASURABLE AMOUNTS OF RAINFALL WILL LIKELY BE PRONE TO
LOCALIZED FLOODING.

ATLANTIC OCEAN...
UPPER LEVEL RIDGING ACROSS THE GULF OF MEXICO CONTINUES INTO THE
WEST ATLC WHERE SURFACE RIDGING IS PRESENT AROUND A 1023 MB HIGH
NEAR 30N70W. TO THE EAST...A SHORTWAVE UPPER TROUGH EXTENDS FROM
33N58W TO 27N68W SUPPORTING A STATIONARY FRONTAL BOUNDARY ALONG
32N56W 22N67W. ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF
THE AXIS. A WEAK SURFACE TROUGH IS TO THE EAST ALONG 30N52W
27N47W WITH NO NOTABLE PRECIPITATION. THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS DOMINATED BY BROAD SURFACE RIDGING
AROUND A 1033 MB HIGH NEAR 42N30W. ALOFT...BROAD UPPER RIDGING
COVERS THE TROPICAL ATLC WITH AN UPPER LEVEL LOW TO THE NORTH
NEAR 31N39W.

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

$$
WALTON

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