[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUN 30 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 19N22W TO 11N23W MOVING W NEAR 10-15 KT.
UPPER AIR TIME SECTION DATA FROM DAKAR SENEGAL INDICATES THAT
THE WAVE MOVED OFF THE COAST OF AFRICA BETWEEN 28/1200 UTC AND
29/0000 UTC. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THE
WAVE LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE. THERE IS
ALSO A BROAD CLEARING WITHIN THE SAHARAN AIR LAYER. SCATTERED
MODERATE CONVECTION IS S OF THE WAVE FROM 6N-9N BETWEEN 19W-26W.

LOW-AMPLITUDE TROPICAL WAVE IS ALONG 12N36W TO 8N37W MOVING W
NEAR 10-15 KT. THE WAVE WAS ADDED DUE TO A TRACKABLE AREA OF
CONVECTION THAT COULD BE TRACED BACK TO THE COAST OF AFRICA.
HOWEVER...THE EXACT LOCATION OF THE WAVE IS DIFFICULT TO DISCERN
DUE TO ITS LOW-AMPLITUDE. SCATTERED MODERATE CONVECTION IS FROM
8N-10N BETWEEN 35W-39W.

TROPICAL WAVE IS ALONG 19N58W TO 11N57W MOVING W NEAR 15-20 KT.
THE WAVE COINCIDES WITH A SURGE IN DEEP LAYER MOISTURE EVIDENT
IN TOTAL PRECIPITABLE WATER IMAGERY. VISIBLE SATELLITE IMAGERY
SHOWS BROAD LOW-LEVEL CYCLONIC FLOW NEAR THE WAVE AXIS WHICH IS
CONFIRMED BY AN OSCAT SCATTEROMETER PASS. SCATTERED MODERATE
CONVECTION IS E OF THE WAVE AXIS FROM 10N-15N BETWEEN 54W-58W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
MAURITANIA NEAR 17N16W CONTINUING ACROSS ATLC WATERS ALONG
11N24W 9N34W 6N41W. THE ITCZ CONTINUES FROM 6N41W TO 3N52W.
BESIDES CONVECTION NEAR TROPICAL WAVES...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-10N BETWEEN
26W-33W.

...DISCUSSION...

GULF OF MEXICO...
DESPITE SURFACE RIDGING AROUND A 1018 MB HIGH OFF THE W COAST OF
FLORIDA NEAR 26N83W...ACTIVE WEATHER CONTINUES ACROSS THE NW
GULF OF MEXICO AND NE MEXICO DUE TO THE UPPER LEVEL PATTERN. A
STRONG UPPER LEVEL LOW IS SITUATED OVER NE MEXICO NEAR 27N101W
PROVIDING DIFFLUENCE ALOFT ACROSS THE NW GULF. CURRENTLY A LARGE
CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS FROM 24N-28N BETWEEN
92W-96W. STRONG SHOWERS/THUNDERSTORMS ALSO COVER MUCH OF MEXICO
AND SRN TEXAS. A SURFACE TROUGH HAS FORMED ALONG THE TEXAS
COASTLINE ALONG 29N95W TO 27N97W. UPPER LEVEL RIDGING COVERS THE
CENTRAL GULF FROM MISSISSIPPI TO THE BAY OF CAMPECHE WHILE AN
INVERTED UPPER TROUGH COVERS THE ERN GULF. THIS SECOND UPPER
TROUGH AND THE UPPER RIDGE ARE ACCOMPANIED BY DRY AIR ALOFT
WHICH IS HELPING PROVIDE FAIR CONDITIONS E OF 90W EXCEPT FOR A
FEW SHOWERS/THUNDERSTORMS THAT HAVE POPPED UP OVER S
FLORIDA...WRN CUBA...AND THE FLORIDA STRAITS. WINDS ARE LIGHT
AND ANTI-CYCLONIC AROUND THE SURFACE HIGH IN THE ERN GULF...BUT
REACH UP TO 20 KTS ACROSS THE WRN GULF...AND POSSIBLY HIGHER IN
THUNDERSTORMS. SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE
AREA WITH THE AREA OF ACTIVE WEATHER INB THE NW GULF EXPECTED TO
MOVE INLAND.

CARIBBEAN SEA...
CLEAR SKIES AND FAIR WEATHER ARE ACROSS MUCH OF THE CARIBBEAN
DUE TO DRY AIR ALOFT AROUND  BROAD UPPER LEVEL CYCLONIC FLOW
CENTERED OVER THE BASIN NEAR 14N72W. AFTERNOON CONVECTION ACROSS
THE NRN ISLANDS IS STILL PRESENT ESPECIALLY ACROSS PORTIONS OF
CUBA AND HISPANIOLA. SHOWERS/THUNDERSTORMS ALSO DOT PORTIONS OF
CENTRAL AMERICA...ESPECIALLY COSTA RICA AND PANAMA...DUE TO THE
MONSOON TROUGH THAT EXTENDS THROUGH PANAMA TO NRN COLOMBIA. A
FEW SHOWERS/THUNDERSTORMS ARE IMPACTING THE LESSER ANTILLES E OF
64W FROM 13N-17N DUE TO MOISTURE AHEAD OF A TROPICAL WAVE JUST E
OF THE ISLANDS. TRADEWIND FLOW OF 15-20 KTS IS PRESENT ACROSS
MUCH OF THE BASIN. EXPECT LITTLE CHANGE EXCEPT FOR AN INCREASE
IN SHOWERS/THUNDERSTORMS ACROSS THE ERN CARIBBEAN DUE TO THE
TROPICAL WAVE E OF THE ISLANDS WHICH CONTINUES TO MOVE WWD.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE OVER THE BAHAMAS SUPPORTS A WEAK SURFACE
RIDGE AROUND A 1018 MB HIGH W OF FLORIDA PROVIDING FAIR
CONDITIONS ACROSS THE FAR WRN ATLC. AN UPPER LEVEL TROUGH TO THE
E NEAR 29N58W SUPPORTS A STATIONARY FRONT ENTERING THE
DISCUSSION AREA ALONG 32N61W 29N64W 27N70W. ISOLATED SHOWERS ARE
WITHIN 100 NM S AND E OF THE AXIS. A SURFACE TROUGH IS TO THE S
OF THE FRONT ALONG 25N63W TO 20N69W WITH POSSIBLE ISOLATED
SHOWERS WITHIN 100 NM EITHER SIDE THE AXIS. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE FARTHER E OF THE FRONT FROM
25N-30N BETWEEN 56W-60W IN THE AREA OF DIFFLUENCE ALOFT AROUND
THE UPPER LOW. A WEAK UPPER RIDGE SEPARATES THE UPPER LOW FROM A
SECOND UPPER LOW FARTHER E NEAR 29N36W. THIS UPPER LOW SUPPORTS
A SURFACE TROUGH ALONG 31N33W TO 27N39W. SCATTERED SHOWERS ARE
WITHIN 45 NM EITHER SIDE THE TROUGH AXIS. THE SURFACE TROUGH IS
WITHIN A BROAD SURFACE RIDGE ANCHORED BY A 1031 MB HIGH NEAR THE
AZORES ISLANDS. THE RIDGE IS SUPPORTED BY UPPER LEVEL RIDGING
BOTH N AND S OF THE UPPER LOW. THE RIDGE IS PROVIDING MOSTLY
FAIR CONDITIONS ACROSS THE CENTRAL AND ERN ATLC BESIDES NEAR THE
SURFACE TROUGH. VISIBLE SATELLITE IMAGERY ALONG WITH GOES-R DUST
ENHANCEMENT IMAGERY INDICATE THAT A LARGE AREA OF SAHARAN DUST
EXTENDS FROM THE COAST OF AFRICA AROUND THE TROPICAL WAVES TO
NEAR 50W.

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

$$
WALTON





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