[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 051048
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON AUG 05 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE AXIS EXTENDS FROM 27N45W TO 18N47W MOVING W-NW
NEAR 15 KT AROUND THE SW PERIPHERY OF A SURFACE RIDGE. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED IN A
MODERATE MOIST ENVIRONMENT. METEOSAT-9 SAL TRACKING PRODUCT
CONTINUES TO SHOW SOME DRY AIR SPREADING OVER THE WAVE
ENVIRONMENT WHICH ALONG WITH STRONG WIND SHEAR IS SUPPRESSING
CONVECTION.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR
10N14W TO 09N22W 10N31W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
STARTS NEAR 10N31W AND CONTINUES ALONG 12N40W TO 09N50W 05N53W.
SCATTERED MODERATE CONVECTION IS WITHIN 170 NM EITHER SIDE OF
THE MONSOON TROUGH AXIS. SIMILAR CONVECTION IS FROM 06N-12N
BETWEEN 40W-50W AS WELL AS WITHIN 70 NM EITHER SIDE OF THE ITCZ
AXIS W OF 50W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 0900 UTC...ANTICYCLONIC FLOW IN THE RANGE OF 5-10 KT
SPREADS ACROSS THE BASIN N OF 22N ANCHORED BY A 1017 MB HIGH
NEAR 26N89W BEING SUPPORTED BY A BROAD MIDDLE TO UPPER LEVEL
RIDGE. DRY AIR IN THE LOWER AND MIDDLE LEVELS IS SUPPORTING FAIR
WEATHER ACROSS MOST OF THE GULF THIS MORNING. A SURFACE TROUGH
IS OVER THE BAY OF CAMPECHE EXTENDING FROM 22N90W TO 18N93W AND
ENHANCING SCATTERED MODERATE CONVECTION/TSTMS S OF 20N W OF 94W.

THE CENTER OF HIGH PRESSURE IS EXPECTED TO PERSIST DURING THE
NEXT 48 HOURS. RAINSHOWERS IN THE NE GULF ASSOCIATED WITH THE
FRONTAL SYSTEM UP NORTH ARE LIKELY TO CONTINUE. RAINSHOWERS ARE
ALSO EXPECTED IN THE BAY OF CAMPECHE AS A SURFACE TROUGH MOVES
IN THE AREA.

THE CARIBBEAN SEA...
EXCEPT FOR THE FAR WESTERN CARIBBEAN...THE WINDWARD PASSAGE AND
THE SOUTHERN CARIBBEAN...VERY DRY AIR FROM A SAHARAN OUTBREAK
SPREADS ACROSS THE BASIN IN THE LOWER AND MIDDLE LEVELS WHICH IS
FAVORING FAIR WEATHER. SURFACE RIDGING IS ACROSS THE CARIBBEAN
WITH TRADEWINDS RANGING FROM 20-25 KT OVER THE CENTRAL-SOUTHERN
BASIN AND 5-15 KT ELSEWHERE. ISOLATED MODERATE CONVECTION/TSTMS
ARE WITHIN 200 NM OF THE COAST OF NICARAGUA BEING SUPPORTED BY
HIGH LOW LEVEL MOISTURE AND UPPER LEVEL DIVERGENCE. SIMILAR
CONVECTION IS S OF 11N ASSOCIATED WITH THE MONSOON TROUGH AXIS.
UPPER LEVEL DIFFLUENCE FROM THE BROAD UPPER HIGH CENTERED OVER
LOUISIANA AND THE LOW NE OF THE HISPANIOLA IS ENHANCING ISOLATED
SHOWERS BETWEEN SE CUBA AND JAMAICA. SIMILAR CONVECTION IS OVER
THE W CARIBBEAN S OF 18N W OF 85W DUE TO UPPER LEVEL DIVERGENCE.

DRY AIR IS EXPECTED TO PERSIST OVER MOST OF THE BASIN WITHIN THE
NEXT 48 HOURS SUPPORTING FAIR WEATHER. A TROPICAL WAVE WILL
ENTER THE EASTERN CARIBBEAN TUESDAY.

HISPANIOLA...
CURRENTLY VERY DRY AIR IS ACROSS THE ISLAND SUPPORTING FAIR
WEATHER. A DRY AIRMASS WILL BE MOVING ACROSS THE ISLAND EARLY
TODAY AND CLEAR SKIES WILL PERSIST. HOWEVER...SHOWERS AND TSTMS
ARE EXPECTED IN THE AFTERNOON/EARLY EVENING ENHANCED BY DAYTIME
HEATING AND AN UPPER LEVEL LOW CENTERED NE OF THE ISLAND IN THE
ATLC.

THE ATLANTIC OCEAN...
BESIDES THE TROPICAL WAVE ALREADY DISCUSSED...A PREFRONTAL
TROUGH ENTERS THE AREA OF DISCUSSION IN THE W ATLC NEAR 30N69W
TO 23N77W. SCATTERED MODERATE CONVECTION AND TSTMS ARE N OF 27N
W OF 71W AS WELL AS 80 NM E OF THE TROUGH AXIS N OF 28N. ANOTHER
SURFACE TROUGH EXTENDS AHEAD OF THE TROPICAL WAVE FROM 28N50W TO
22N52W WITH NO CONVECTION ASSOCIATED WITH IT.
OTHERWISE...SURFACE RIDGING AND FAIR WEATHER SUPPORTED BY LOWER-
MIDDLE LEVEL DRY AIR ARE ACROSS THE REMAINDER BASIN.

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

$$
NR


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