[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 062340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUL 06 2012

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
2245 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 23N43W TO 14N40W MOVING W NEAR 15 KT. THE
WAVE LIES ON THE WRN SIDE OF A SURGE OF DEEP LAYER MOISTURE. THE
WAVE ALSO LIES ON THE LEADING EDGE OF A LARGE AREA OF SAHARAN
DUST THAT EXTENDS EWD TO THE AFRICAN COAST. NO DEEP CONVECTION
IS CURRENTLY NEAR THE WAVE DUE TO THE DRY DUST E OF THE AXIS.

ACTIVE TROPICAL WAVE IS MOVING INTO THE WRN CARIBBEAN ALONG
23N78W TO 15N82W MOVING W NEAR 20 KT. TOTAL PRECIPITABLE WATER
IMAGERY INDICATES THAT THE WAVE LIES ON THE WRN SIDE OF A LARGE
SURGE OF DEEP LAYER MOISTURE COVERING THE CENTRAL CARIBBEAN AND
ERN BAHAMAS. SATELLITE IMAGERY ALONG WITH SCATTEROMETER DATA
SHOWS LOW-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. A LARGE
CLUSTER OF STRONG CONVECTION COVERS ERN CUBA FROM 20N-22N
BETWEEN 74W-80W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 22N-25N BETWEEN 71W-77W ACROSS THE ERN BAHAMAS...AND
FROM 14N-19N BETWEEN 77W-85W INCLUDING JAMAICA. SIMILAR ACTIVITY
IS ALSO OVER WRN CUBA AND ACROSS HONDURAS AND NICARAGUA. AREAS
THAT ARE RECEIVING HEAVY RAINFALL ARE AT RISK FOR LOCALIZED
FLOODING AND MUDSLIDES.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
GUINEA-BISSAU AT 12N16W CONTINUING ACROSS ATLC WATERS TO 8N41W.
THE ITCZ BEGINS AT 8N41W TO 5N60W. A LARGE CLUSTER OF STRONG
CONVECTION IS MOVING OFF THE AFRICAN COAST FROM 11N-16N BETWEEN
15W-18W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
8N-10N BETWEEN 22W-26W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL RIDGE COVERS THE ENTIRE ERN CONUS INCLUDING
MUCH OF THE GULF OF MEXICO SUPPORTING A WEAK 1018 MB HIGH
CENTERED NEAR 27N87W. MOSTLY DRY AIR ALOFT IS PROVIDING FAIR
CONDITIONS ACROSS THE GULF WATERS. HOWEVER...A SHORTWAVE UPPER
TROUGH MOVING AROUND THE UPPER RIDGE IS PRODUCING AN AREA OF
STRONG SHOWERS/THUNDERSTORMS ACROSS LOUISIANA AND THE COASTAL
WATERS. THIS CLUSTER OF STORMS APPEARS TO BE MOVING WWD. SOME
ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SE GULF AND
PORTIONS OF THE FLORIDA PENINSULA. LIGHT ANTI-CYCLONIC FLOW IS
AROUND THE RIDGE. MOISTURE AND SHOWER ACTIVITY IS EXPECTED TO
INCREASE ACROSS THE SE GULF AS A TROPICAL WAVE IN THE WRN
CARIBBEAN CONTINUES WWD. WEAK SURFACE RIDGING WILL REMAIN ACROSS
THE BASIN THROUGH THE WEEKEND.

CARIBBEAN SEA...
MOIST CONDITIONS COVER THE NW CARIBBEAN ASSOCIATED WITH A
TROPICAL WAVE EXTENDING FROM CENTRAL CUBA TO E OF NICARAGUA.
STRONG SHOWERS/THUNDERSTORMS COVER WRN CUBA WITH MORE SCATTERED
ACTIVITY OVER WATER. THE ACTIVITY OVER CUBA IS ALSO LIKELY
ENHANCED BY DIFFLUENCE ALOFT AROUND THE ERN SIDE OF A BROAD
UPPER TROUGH COVERING THE EXTREME SRN GULF OF MEXICO AND THE FAR
NW CARIBBEAN. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS.
A LARGE CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS ALSO IN THE
SW CARIBBEAN FROM 10N-12N BETWEEN 80W-83W. EVEN THOUGH THE
TROPICAL WAVE IS JUST N OF THIS CLUSTER...IT IS MOST LIKELY
ASSOCIATED WITH THE MONSOON TROUGH EXTENDING FROM THE E PACIFIC
ACROSS COSTA RICA TO NRN COLOMBIA. THIS SECTION ALSO LIES
UNDERNEATH AN AREA OF DIFFLUENCE ALOFT ON THE WRN SIDE OF AN
UPPER LEVEL RIDGE COVERING THE SW GULF. THE CENTRAL AND ERN
CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR
ALOFT AROUND AN UPPER LEVEL RIDGE COVERING THE ERN CARIBBEAN.
TRADEWIND FLOW OF 15-20 KT IS ACROSS MUCH OF THE BASIN REACHING
25 KT IN THE CENTRAL CARIBBEAN. EXPECT THE TROPICAL WAVE TO
CONTINUE MOVING WWD ACROSS THE BASIN WITH FAIR WEATHER REMAINING
IN ITS WAKE.

ATLANTIC OCEAN...
DRY AIR ALOFT AROUND A BROAD UPPER LEVEL RIDGE IS PROVIDING FAIR
CONDITIONS ACROSS MUCH OF THE WRN ATLC. SHOWERS/THUNDERSTORMS
ARE IMPACTING THE ERN BAHAMAS DUE TO A TROPICAL WAVE IN THE WRN
CARIBBEAN. ANOTHER UPPER LEVEL RIDGE IS ALONG 63W PROVIDING MORE
FAIR WEATHER AND SUPPORTING WEAK SURFACE RIDGING. AN UPPER LEVEL
LOW IS TO THE E CENTERED NEAR 27N54W...BUT IS NOT CAUSING ANY
SIGNIFICANT WEATHER. A BROAD UPPER LEVEL RIDGE ACROSS THE NRN
ATLC SUPPORTS A BROAD SURFACE RIDGE ANCHORED BY A 1030 MB AZORES
HIGH...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE CENTRAL AND
ERN ATLC. UPPER LEVEL RIDGING ALSO COVERS THE TROPICAL ATLC
CENTERED NEAR 2140W. THE LAST VISIBLE SATELLITE IMAGES OF THE
DAY INDICATE A LARGE AREA OF DUST EXTENDING FROM THE AFRICAN
COAST TO THE TROPICAL WAVE IN THE TROPICAL ATLC. DUST IS ALSO
PRESENT W OF THE WAVE TO THE ERN CARIBBEAN.

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

$$
WALTON




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