[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN JUL 10 2011

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1630 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLANTIC IS ANALYZED FROM
14N43W TO 5N49W MOVING W NEAR 15-20 KT. WAVE IS AT THE LEADING
EDGE OF AN AREA OF DEEP MOISTURE AS DEPICTED IN THE TOTAL
PRECIPITABLE WATER IMAGERY AND IS WELL-DEFINED IN THE SATELLITE
FEATURE WINDS AS WELL AS THE 1212Z ASCAT PASS. NO SIGNIFICANT
DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE...THOUGH
SCATTERED SHOWERS ARE PRESENT WITHIN 120 NM E OF THE WAVE AXIS.
A SECONDARY FEATURE...WHICH MAY BE AN UNDIAGNOSED WAVE...IS
ALONG 38W AND HAS SEEN PERSISTENT SHOWERS OVER THE LAST
DAY...BUT LITTLE DEEP CONVECTION.

TROPICAL WAVE IN THE CARIBBEAN IS ANALYZED ALONG 72W S OF 19N
FROM HISPANIOLA TO INLAND OVER COLUMBIA MOVING W NEAR 15 KT.
WAVE IS EMBEDDED WITHIN AN AREA OF ENHANCED LOW-MID LEVEL
MOISTURE AS DEPICTED IN THE TOTAL PRECIPITABLE WATER
IMAGERY...THOUGH LITTLE EVIDENCE OF THE SYSTEM IS EVIDENT IN THE
SURFACE OBSERVATIONS. NO SIGNIFICANT DEEP CONVECTION AND ONLY
MINIMAL SHOWER ACTIVITY IS CURRENTLY ASSOCIATED WITH THE WAVE.

THE TROPICAL WAVE PREVIOUSLY ANALYZED AS BEING OVER CENTRAL CUBA
HAS BEEN REPOSITIONED FARTHER WEST OVER THE GULF OF MEXICO
EXTENDING FROM 23N90W TO OVER MEXICO TO 13N93W IN THE NORTHEAST
PACIFIC.  NO SIGNIFICANT DEEP CONVECTION IS CURRENTLY ASSOCIATED
WITH THE WAVE...THOUGH SCATTERED SHOWERS ARE PRESENT WITHIN 180
NM OF THE WAVE AXIS.  THE WAVE IS EVIDENT AS A MAXIMUM IN THE
TOTAL PRECIPITABLE WATER IMAGERY JUST EAST OF THE WAVE AXIS AS
WELL AS MEXICAN SURFACE OBSERVATIONS AND EARLIER ASCAT AND
WINDSAT PASSES.  THERE DOES REMAIN A FEATURE OVER CENTRAL
CUBA...WHICH IS NOW DENOTED AS A TROUGH.  NO SIGNIFICANT DEEP
CONVECTION OR SHOWER ACTIVITY IS CURRENTLY ASSOCIATED WITH THIS
TROUGH.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA INTO THE E
TROPICAL ATLANTIC FROM 18N16W TO 9N24W. THE ITCZ AXIS CONTINUES
FROM THIS POINT ALONG 6N34W TO 10N44W TO INLAND OVER SOUTH
AMERICA NEAR 6N47W. A SEPARATE MONSOON TROUGH EXTENDS FROM THE
COAST OF COLUMBIA TO COSTA RICA FROM 10N76W TO 10N83W.
SCATTERED WEAK TO MODERATE CONVECTION IS MOVING OFF THE COAST OF
AFRICA FROM 5N-11N E OF 18W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS WITHIN 240 NM S OF THE MONSOON TROUGH IN
THE SOUTHWESTERN CARIBBEAN.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING CONTINUES ACROSS THE NORTHERN GULF OF MEXICO
WITH WEAK EAST TO SOUTHEAST WINDS PREVAILING.  ISOLATED SHOWERS
ARE PRESENT THROUGHOUT THE GULF OF MEXICO NORTH OF 23N...THOUGH
NO SIGNIFICANT DEEP CONVECTION IS CURRENTLY OCCURRING.  IN THE
UPPER LEVELS...THE COMBINATION OF AN UPPER-LEVEL LOW OVER
SOUTHERN TEXAS AND A UPPER HIGH OVER THE PANHANDLE OF FLORIDA IS
ADVECTING UPPER LEVEL MOISTURE AND CLOUDINESS OVER MOST OF THE
GULF OF MEXICO.  WEATHER ASSOCIATED WITH THE TROPICAL WAVE IN
THE WESTERN GULF OF MEXICO IS MENTIONED ABOVE.  LITTLE CHANGE IN
THESE CONDITIONS ARE EXPECTED DURING THE NEXT DAY.

CARIBBEAN SEA...
A MODERATE SURFACE PRESSURE GRADIENT ACROSS THE CARIBBEAN IS
PRODUCING EASTERLY TRADEWINDS 15-25 KT WITH THE STRONGEST WINDS
JUST NORTH OF COLOMBIA.  SCATTERED MODERATE CONVECTION IS
OCCURRING WITHIN 120 NM OF THE COAST OF NICARAGUA. IN THE UPPER
LEVELS...AN UPPER LOW IS SITUATED IN THE NW CARIBBEAN NEAR
18N81W WITH RIDGING COVERING THE EASTERN CARIBBEAN ALONG 14N.
WEATHER ASSOCIATED WITH THE TROPICAL WAVE IN THE CENTRAL
CARIBBEAN AND THE TROUGH OVER CUBA IS MENTIONED ABOVE.  LITTLE
CHANGE IN THE SURFACE FLOW IS LIKELY DURING THE NEXT DAY BUT
CHANCES FOR PRECIPITATION IN THE WESTERN CARIBBEAN SHOULD
INCREASE AS THE TROPICAL WAVE MOVES WESTWARD.

SOMETHING TO KEEP IN MIND...THE MONSOON TROUGH IN THE NORTHEAST
PACIFIC IS EXPECTED TO SHIFT NORTHWARD WHERE IT IS FORECAST TO
EXTEND ACROSS SOUTHERN MEXICO AND CENTRAL AMERICA BY
WEDNESDAY...BECOMING CONSIDERABLY STRONGER BY THE END OF THIS
WEEK.  IN RESPONSE TO THIS...ABUNDANT TROPICAL MOISTURE FROM THE
SOUTHWEST WINDS WILL ADVECT INTO CENTRAL AMERICA...POTENTIALLY
GENERATING AREAS OF HEAVY RAINFALL AND POSSIBLE MUDSLIDES OVER
PORTIONS OF CENTRAL AMERICA AND SOUTHERN MEXICO...ESPECIALLY FOR
THE SECOND HALF OF THIS WEEK. FOR NOW...WE WILL CONTINUE
MONITORING MEDIUM RANGE FORECAST MODELS FOR CONSISTENCY ON THIS
POSSIBLE SCENARIO.

ATLANTIC OCEAN...
SURFACE RIDGING EXTENDING ENE-WSW FROM A 1030 MB HIGH JUST NORTH
OF OUR REGION AT 34N34W IS DOMINATING THE WEATHER OVER THE
SUBTROPICAL AND TROPICAL NORTH ATLANTIC TODAY.  THE STRONGEST
GRADIENT FROM THIS RIDGING EXISTS IN THE EASTERN ATLANTIC WITH NE
WINDS 20-30 KT FROM THE CAPE VERDE ISLANDS NORTHEASTWARD TO THE
CANARY ISLANDS.  ELSEWHERE THE REMAINDER OF OUR AREA HAS
GENERALLY WEAK SURFACE WINDS.  A SURFACE TROUGH OF LOW
PRESSURE...WHICH IS BEING INDUCED BY A VIGOROUS UPPER LEVEL
LOW...IS LOCATED ALONG 31N55W TO 26N57W. SCATTERED SHOWERS AND
THUNDERSTORMS ARE LOCATED WITHIN 120 NM OF THE TROUGH AXIS.  IN
THE UPPER LEVELS...AN UPPER TROUGH EXTENDS SOUTHWESTWARD FROM
THE UPPER LOW NEAR 27N55W TO 20N73W.  ELSEWHERE UPPER LEVEL
RIDGING DOMINATES THE REMAINDER OF THE SUBTROPICAL AND TROPICAL
NORTH ATLANTIC.  WEATHER ASSOCIATED WITH THE TROPICAL WAVE IN
THE CENTRAL ATLANTIC IS MENTIONED ABOVE.  AS THE SURFACE HIGH
SHOULD WEAKEN AND MOVE TOWARD THE WEST SOME...FORCING IN THE
EASTERN ATLANTIC WILL SLACKEN AND THE WINDS THERE SHOULD WEAKEN
DURING THE NEXT DAY.

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

$$

LANDSEA/MOSES




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