[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI JUN 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 13N21W TO 05N22W MOVING WEST NEAR 5
KT. THE WAVE AXIS IS MOSTLY EMBEDDED IN A MODERATE MOIST
ENVIRONMENT WITHIN THE ITCZ AND HAVE NO CONVECTIVE ACTIVITY
ASSOCIATED TO IT AT THIS TIME. THE METEOSAT-9 SAL TRACKING
PRODUCT INDICATES THE WAVE IS BEING ENGULFED BY SAL DRY AIR
WHICH MAY BE LIMITING ANY FORM OF CONVECTION.

TROPICAL WAVE IS ALONG 15N48W TO 03N51W MOVING WEST NEAR 10 KT.
THE WAVE IS EMBEDDED IN A MOSTLY MODERATE MOIST ENVIRONMENT
WITHIN THE ITCZ WITH PATCHES OF HIGH MOISTURE SE-SW OF THE AXIS.
SCATTERED MODERATE CONVECTION COINCIDES WITH THE AREAS OF HIGH
MOISTURE FROM 0N-04N BETWEEN 42W-50W AND FROM 07N-10N BETWEEN
52W-58W. SCATTERED SHOWERS ARE FROM 06N-09N BETWEEN 42W-46W.

TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN ALONG
21N73W TO 10N74W MOVING WEST NEAR 10 KT. MODERATE LOW LEVEL
MOISTURE IS AHEAD OF THE WAVE AXIS ACROSS THE WINDWARD PASSAGE
AND OVER HAITI COINCIDING WITH SCATTERED MODERATE CONVECTION
FROM 17N-21N BETWEEN 71W-76W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN WEST COAST NEAR
13N16W TO 09N21W. THE ITCZ BEGINS WEST OF A TROPICAL WAVE NEAR
08N24W AND CONTINUES ALONG 05N38W 01N49W. ANY DEEP CONVECTION
NEAR THE ITCZ/MONSOON TROUGH IS ASSOCIATED WITH TROPICAL WAVES
AND IS DISCUSSED IN THAT SECTION ABOVE.

...DISCUSSION...

GULF OF MEXICO...
WEAK SURFACE RIDGING IS ACROSS THE GULF OF MEXICO AROUND A 1016
MB HIGH NEAR 27N88W. LIGHT ANTI-CYCLONIC FLOW OF 5-10 KT IS
AROUND THE RIDGE. ALOFT...UPPER TROUGHING DOMINATES WITH AN AXIS
EXTENDING THROUGH CENTRAL FLORIDA. THE REMAINDER BECOMES A CUT-
OFF UPPER LOW IN THE BAY OF CAMPECHE NEAR 23N94W. THE UPPER LOW
IS PROVIDING DIFFLUENT FLOW ALOFT OVER THE YUCATAN PENINSULA
SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS SOUTH OF 22N BETWEEN
85W-92W. WEAK SURFACE RIDGING WILL REMAIN OVER THE AREA WITHIN
THE NEXT 48 HOURS...A COLD FRONT IS EXPECTED TO EXTEND ACROSS
THE NORTHERN GULF SATURDAY AFTERNOON.

CARIBBEAN SEA...
A TROPICAL WAVE WITH AXIS CROSSING THE WINDWARD PASSAGE EXTENDS
FROM 21N73W TO 10N74W. MODERATE LOW LEVEL MOISTURE IS ACROSS THE
WINDWARD PASSAGE AND OVER HAITI COINCIDING WITH SCATTERED
MODERATE CONVECTION AND ISOLATED THUNDERSTORM ACTIVITY FROM 17N-
21N BETWEEN 71W-76W. LARGE CLUSTERS WITH STRONG CONVECTION AND
NUMEROUS THUNDERSTORMS ARE OVER NORTHERN COLOMBIA AND PANAMA.
THIS CONVECTIVE ACTIVITY EXTENDS SCATTERED MODERATE CONVECTION
OVER THE SOUTHERN CARIBBEAN S OF 11N WHERE MODERATE TO HIGH LOW
LEVELS MOISTURE LIES. THE CONVECTIVE ACTIVITY OVER THE ABOVE
MENTIONED REGION IS MOSTLY ASSOCIATED WITH THE MONSOON TROUGH
AXIS WHICH MOVES ACROSS FROM COSTA RICA TO COLOMBIA.
ALOFT...BROAD UPPER RIDGING COVERS THE MAJORITY OF THE BASIN
CENTERED NEAR 12N74W WHILE BROAD UPPER TROUGHING COVERS THE FAR
EASTERN CARIBBEAN. TRADEWINDS OF 10-15 KT ARE ACROSS MOST OF THE
BASIN EXCEPT THE CENTRAL CARIBBEAN WHERE WINDS ARE 20-25 KT DUE
TO A TIGHTER PRESSURE GRADIENT. THE WAVE WILL CONTINUE TO MOVE
WEST AND ITS AXIS IS EXPECTED TO BE OFF WESTERN CUBA FRIDAY
AFTERNOON. WINDS IN THE CENTRAL CARIBBEAN ARE EXPECTED TO
SUBSIDE TO LESS THAN 25 KT BY SATURDAY AFTERNOON WHILE A NEW
WAVE MOVES ACROSS THE LESSER ANTILLES CARRYING LOTS OF MOISTURE.

HISPANIOLA...
MODERATE LOW LEVEL MOISTURE IS ACROSS THE WINDWARD PASSAGE AND
OVER HAITI COINCIDING WITH SCATTERED MODERATE CONVECTION AND
ISOLATED THUNDERSTORM ACTIVITY FROM 17N-21N BETWEEN 71W-76W.
THIS MOISTURE AND CONVECTIVE ACTIVITY IS ASSOCIATED WITH A
TROPICAL WAVE WITH AXIS CROSSING THE WINDWARD PASSAGE. MOISTURE
ASSOCIATED WITH THIS WAVE IS EXPECTED TO FADE NEAR MIDNIGHT ON
FRIDAY. FAIR WEATHER CAN BE EXPECTED THEN AND THROUGHOUT AT
LEAST SUNDAY MORNING. CONDITIONS CAN DETERIORATE AGAIN MONDAY
MORNING AS A NEW TROPICAL WAVE WILL BE CROSSING THE EASTERN
CARIBBEAN BRINGING LOTS OF MOISTURE AND INCREASING
ATMOSPHERE INSTABILITY.

ATLANTIC OCEAN...
BROAD SURFACE RIDGING COVERS THE WEST ATLC AROUND A 1022 MB HIGH
NEAR 31N60W. ALOFT...AN UPPER RIDGE IS ALONG 76W...WHILE AN
UPPER LOW SPINS TO THE EAST NEAR 24N63W. THE UPPER LOW IS
SUPPORTING A SURFACE TROUGH ALONG 24N63W TO 20N67W. SCATTERED
SHOWERS ARE FROM 20N-24N BETWEEN 58W-63W ASSOCIATED WITH THIS
FEATURE. AT THE SURFACE...BROAD RIDGING DOMINATES EXTENDING FROM
A 1038 MB HIGH NEAR 46N22W. UPPER RIDGING ALSO COVERS THE
EXTREME TROPICAL ATLC. THE METEOSAT-9 SAL TRACKING PRODUCT
DEPICTS A LARGE AREA OF SAHARAN DRY AIR EXTENDS FROM THE COAST
OF AFRICA TO NEAR 55W AROUND THE TROPICAL WAVE THAT WILL ENTER
THE EASTERN CARIBBEAN BY SATURDAY AFTERNOON.

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

$$
RAMOS


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