[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130548
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED JUL 13 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0500 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE ERN TRPCL ATLC IS ALONG 16N27W TO 10N31W
MOVING W 10-15 KT. WAVE IS LOW AMPLITUDE...BUT CYCLONIC FLOW
AROUND THE AXIS IS INDICATED IN SATELLITE DERIVED WINDS. NO DEEP
CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.

TROPICAL WAVE JUST E OF THE LESSER ANTILLES EXTENDS FROM NEAR
18N59W TO 8N62W MOVING W 10-15 KT. WAVE CONTINUES TO PRECEDE A
SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER
IMAGERY. A CLUSTER OF STRONG CONVECTION IS FROM 17N-20N BETWEEN
54W-57W. ISOLATED MODERATE CONVECTION IS WITHIN 75 NM EITHER
SIDE OF THE AXIS.

TROPICAL WAVE JUST E OF THE YUCATAN PENINSULA EXTENDS ALONG
21N87W TO 14N88W MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN A
BROAD AREA OF ENHANCED MOISTURE ACROSS THE NW CARIBBEAN AND SW
GULF OF MEXICO. BASED ON THE AREA OF MAXIMUM MOISTURE AND
CYCLONIC FLOW EVIDENT IN SATELLITE IMAGERY...THE WAVE APPEARS TO
HAVE SPED UP AND BE FARTHER W THAN CURRENTLY DEPICTED. THE WAVE
WILL LIKELY BE RELOCATED ON THE NEXT ANALYSIS. THE WAVE
CONTINUES TO LIE UNDER DIFFLUENT FLOW ALOFT WHICH IS HELPING
ENHANCE CONVECTION. SCATTERED MODERATE/STRONG CONVECTION IS FROM
17N-22N BETWEEN 91W-95W...AND FROM 14N-17N BETWEEN 88W-90W.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 24N ALONG 22N15W 12N21W 8N37W. THE ITCZ CONTINUES FROM 8N37W
TO 6N54W. ISOLATED MODERATE CONVECTION IS WITHIN 180 NM S OF THE
AXIS BETWEEN 22W-43W.

...DISCUSSION...

GULF OF MEXICO...
A TROPICAL WAVE JUST E OF THE YUCATAN PENINSULA IS CAUSING
SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE BAY OF CAMPECHE S OF
22N BETWEEN 90W-95W. WEAK SURFACE RIDGING ALONG 25N COVERS THE
REMAINDER OF THE GULF OF MEXICO EXTENDING FROM THE ATLC
SUPPORTING FAIR WEATHER AND LIGHT ANTI-CYCLONIC FLOW AROUND THE
RIDGE. A FEW ISOLATED SHOWERS...REMNANTS OF AFTERNOON
CONVECTION...ARE ACROSS THE NE GULF FROM 28N-30N BETWEEN
85W-90W. ALOFT...AN UPPER LEVEL RIDGE COVERS THE NRN GULF
CENTERED OVER CENTRAL ALABAMA. AN INVERTED UPPER LEVEL TROUGH
COVERS THE SW GULF WITH AXIS FROM 18N98W TO 28N93W. WATER VAPOR
IMAGERY INDICATES DRY AIR IS WRAPPING AROUND THE SRN EXTENT OF
THE UPPER RIDGE WHICH IS FURTHER SUPPORTING THE FAIR WEATHER.
TOTAL PRECIPITABLE WATER IMAGERY STILL INDICATES ENHANCED
MOISTURE IS ACROSS THE NRN GULF. WITH DAYTIME HEATING THIS WILL
LIKELY MEAN SHOWERS/THUNDERSTORMS WILL POP UP LATER IN THE
AFTERNOON TODAY. SHOWER/THUNDERSTORM ACTIVITY WILL ALSO CONTINUE
IN THE SW GULF AS THE TROPICAL WAVE MOVES WWD. WEAK SURFACE
RIDGING WILL CONTINUE OVER THE NRN GULF.

CARIBBEAN SEA...
THE NW CARIBBEAN IS CURRENTLY UNDER FAIR CONDITIONS AS
MOISTURE ASSOCIATED WITH A TROPICAL WAVE JUST E OF THE YUCATAN
PENINSULA HAS MOVED MAINLY INTO THE SW GULF OF MEXICO. THE SW
CARIBBEAN REMAINS UNDER MOIST CONDITIONS INFLUENCED BY THE
MONSOON TROUGH THAT EXTENDS FROM THE E PACIFIC ACROSS CENTRAL
NICARAGUA TO NRN COLOMBIA. A CLUSTER OF STRONG
SHOWERS/THUNDERSTORMS IS CURRENTLY FROM 10N-12N BETWEEN
75W-79W...AND INLAND OVER COLOMBIA FROM 4N-11N BETWEEN 71W-76W.
ISOLATED SHOWERS/THUNDERSTORMS COVER THE REMAINDER OF THE AREA S
OF 14N BETWEEN 73W-84W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO
ACROSS HISPANIOLA WITH ISOLATED ACTIVITY OVER PUERTO RICO. THIS
ACTIVITY IS GENERATED BY THE COMBINATION OF ENHANCED MOISTURE
ACROSS THIS AREA EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY
ALONG WITH DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH
CENTERED NEAR 16N75W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS
ARE ALSO ACROSS THE WINDWARD ISLANDS DUE TO AN APPROACHING
TROPICAL WAVE JUST E OF THE ISLANDS. EXPECT SHOWER/THUNDERSTORM
ACTIVITY TO PERSIST ACROSS THE WINDWARD ISLANDS DUE TO THE
WAVE...AS WELL AS ACROSS THE N CENTRAL ISLANDS. ALSO...MUCH OF
CENTRAL AMERICA AND SRN MEXICO IS AT THREAT FOR PROLONGED HEAVY
RAINFALL THROUGHOUT THE END OF THE WEEK WHICH WILL INCREASE THE
CHANCE FOR DEADLY FLOODING AND MUDSLIDES. MODEL GUIDANCE
INDICATES THE MONSOON TROUGH WILL CONTINUE TO LIFT FARTHER N
PLACING ABNORMALLY STRONG WLY FLOW AGAINST CENTRAL AMERICA AND
SRN MEXICO. THIS W-SW FLOW WILL DRAW SIGNIFICANT TROPICAL
MOISTURE ACROSS THESE AREAS. COMBINED WITH OROGRAPHIC LIFT DUE
TO MOUNTAINS THIS CREATES A FORMULA TO EQUAL HEAVY
PRECIPITATION. THESE AREAS SHOULD MONITOR THE SITUATION OVER THE
NEXT FEW DAYS AND STAY TUNED FOR UPDATES ON THIS POSSIBLY
DANGEROUS SCENARIO.

ATLANTIC OCEAN...
SURFACE RIDGING DOMINATES THE MAJORITY OF THE ATLC ANCHORED BY A
1031 MB AZORES HIGH NEAR 41N27W PROVIDING FAIR CONDITIONS
BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE WRN ATLC
CENTERED OVER CENTRAL ALABAMA. AN UPPER LEVEL TROUGH IS TO THE E
ALONG 51W. A SHORTWAVE UPPER TROUGH EXTENDS OFF THE MAIN TROUGH
EXTENDING TO THE CENTRAL BAHAMAS. THIS IS PRODUCING SOME UPPER
LEVEL CLOUDS AND ISOLATED SHOWERS FROM 25N-32N BETWEEN 52W-60W.
UPPER LEVEL RIDGING COVERS MUCH OF THE ERN ATLC CENTERED NEAR
35N32W. AN UPPER LEVEL TROUGH COVERS THE FAR ERN ATLC CENTERED
OVER THE MADEIRA ISLANDS. ACROSS THE TROPICAL ATLC...AN UPPER
LEVEL LOW IS CENTERED NEAR 25N38W...AND AN UPPER LEVEL RIDGE IS
CENTERED OFF THE W COAST OF AFRICA NEAR 20N24W.

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

$$
WALTON




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