[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131116
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1100 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE ERN TRPCL ATLC IS ALONG 15N28W 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 ACROSS THE LESSER ANTILLES EXTENDS FROM NEAR
19N59W TO 10N63W MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN A
SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
13N-18N BETWEEN 58W-62W...AND FROM 13N-15N BETWEEN 62W-66W.

TROPICAL WAVE PREVIOUSLY E OF THE YUCATAN PENINSULA HAS BEEN
RELOCATED FARTHER W AND NOW EXTENDS ALONG 22N92W TO 15N92W
MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF
ENHANCED MOISTURE ACROSS THE SW GULF OF MEXICO. THE WAVE
CONTINUES TO LIE UNDER DIFFLUENT FLOW ALOFT WHICH IS HELPING
ENHANCE CONVECTION. SCATTERED MODERATE/STRONG CONVECTION IS FROM
15N-22N BETWEEN 93W-95W.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 21N ALONG 17N14W 11N22W 8N35W. ITCZ CONTINUES FROM 8N35W TO
5N56W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
4N-7N BETWEEN 12W-15W...AND FROM 7N-9N BETWEEN 27W-32W.

...DISCUSSION...

GULF OF MEXICO...
A TROPICAL WAVE IN THE BAY OF CAMPECHE IS CAUSING SCATTERED
SHOWERS/THUNDERSTORMS S OF 24N BETWEEN 92W-98W. 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 AXIS. A FEW ISOLATED SHOWERS
THUNDERSTORMS ARE NOTED ACROSS THE NRN GULF N OF 26N BETWEEN
83W-93W WHERE ENHANCED MOISTURE VALUES ARE INDICATED BY TOTAL
PRECIPITABLE WATER IMAGERY. ALOFT...AN UPPER LEVEL RIDGE COVERS
THE NRN GULF CENTERED OVER CENTRAL ALABAMA. AN INVERTED UPPER
LEVEL TROUGH COVERS THE FAR SW GULF WITH AXIS OVER MEXICO. A
WEAK AND NARROW UPPER RIDGE IS TO THE E EXTENDING ACROSS THE
YUCATAN PENINSULA. THIS PATTERN IS CREATING DIFFLUENCE ALOFT
OVER THE TROPICAL WHICH IS ENHANCING SOME OF THE ACTIVITY IN ITS
VICINITY. WATER VAPOR IMAGERY INDICATES DRY AIR IS WRAPPING
AROUND THE SRN EXTENT OF THE UPPER RIDGE WHICH IS FURTHER
SUPPORTING THE FAIR WEATHER. WITH MOISTURE ALREADY IN PLACE
ACROSS THE NE GULF...DAYTIME HEATING 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 HAS NOW MOVED OVER 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. STRONG
SHOWERS/THUNDERSTORMS ARE CURRENTLY FROM 8N-12N BETWEEN
74W-80W...AND FROM 11N-13N BETWEEN 80W-83W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO ACROSS HISPANIOLA FROM
17N-21N BETWEEN 67W-70W...WITH ISOLATED ACTIVITY N OF 16N
BETWEEN 65W-77W. THIS ACTIVITY IS GENERATED BY THE COMBINATION
OF ENHANCED MOISTURE ACROSS THIS AREA EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY ALONG WITH DIFFLUENCE ALOFT AROUND A
HORIZONTALLY ALIGNED UPPER LEVEL TROUGH ALONG 20N CENTERED OVER
CUBA NEAR 21N79W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE
ALSO ACROSS THE WINDWARD ISLANDS E OF 66W DUE TO TROPICAL WAVE
MOVING INTO THE ERN CARIBBEAN. 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 PROGRESS OF THIS
SCENARIO.

ATLANTIC OCEAN...
SURFACE RIDGING DOMINATES THE MAJORITY OF THE ATLC ANCHORED BY A
1030 MB AZORES HIGH NEAR 40N27W 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 CENTRAL CUBA. THIS IS PRODUCING SOME UPPER LEVEL
CLOUDS AND ISOLATED SHOWERS FROM 23N-32N BETWEEN 50W-60W. UPPER
LEVEL RIDGING COVERS MUCH OF THE ERN ATLC CENTERED NEAR 36N34W.
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 25N40W...AND AN UPPER LEVEL RIDGE IS CENTERED
OFF THE W COAST OF AFRICA NEAR 19

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

$$
WALTON





This weather bulletin was brought to you by:
www.nashvilleweather.net