[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102356 CCA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 10 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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
2315 UTC.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W SOUTH OF 18N MOVING
WEST 15-20 KT. THIS WAVE CONTINUES TO HAVE A WELL DEFINED
STRUCTURE WITH AN INVERTED V-SHAPE AND A GOOD AMOUNT OF LOW-MID
LEVEL CYCLONIC TURNING. DESPITE THE WELL-DEFINED
STRUCTURE...THE WAVE IS EMBEDDED IN A VERY DRY ENVIRONMENT
LIMITING ANY SIGNIFICANT CONVECTION FROM DEVELOPING. HOWEVER
THERE ARE SCATTERED SHOWERS AND TSTMS NEAR THE ITCZ AXIS LIKELY
ENHANCED BY THIS WAVE...DISCUSSED IN MORE DETAIL IN THE ITCZ
SECTION.

A TROPICAL WAVE IS IN THE EASTERN CARIBBEAN ALONG 65W S OF 20N
MOVING W NEAR 20 KT. THIS WAVE SHOWED SOME SIGNS OF POSSIBLY
DEVELOPING YESTERDAY EVENING WITH A CLEAR MID-LEVEL CIRCULATION
FORMING ALONG OR JUST AHEAD OF THE WAVE AXIS. SINCE THEN...THE
APPEARANCE OF THIS WAVE HAS DETEORIATED ON SATELLITE IMAGERY
WITH LITTLE ORGANIZATION OF ITS SHOWER ACTIVITY. IN FACT...THE
PRECIP CONTINUES TO BECOME INCREASINGLY MORE DISORGANIZED WITH
ONLY ISOLATED TO SCATTERED SHOWERS FOUND WITHIN 350 NM EITHER
SIDE OF THE WAVE AXIS. THE UPPER LEVEL ENVIRONMENT IS
UNFAVORABLE WITH STRONG NLY WINDS AND WIDESPREAD DRY AIR ON THE
W SIDE OF AN UPPER LOW N OF THE VIRGIN ISLANDS.

A TROPICAL WAVE IS ALONG 95W MOVING W 15-20 KT. THIS WAVE HAS
MOVED ALMOST ENTIRELY INTO THE E PACIFIC BASIN AND HAS BECOME
ILL-DEFINED.

...THE ITCZ...
ITCZ IS CENTERED ALONG 12N15W 11N30W 12N45W 10N54W 12N64W. THERE
ARE NO ANY AREAS OF SIGNIFICANT CONVECTION NEAR THE AXIS THIS
EVENING. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 300 NM
TO THE S OF THE AXIS E OF 41W. SOME OF THIS ACTIVITY IS BECOMING
A LITTLE MORE CONCENTRATED BETWEEN 31W-41W LIKELY ENHANCED BY
THE TROPICAL WAVE ALONG 43W. SIMILAR ACTIVITY IS WITHIN 240 NM
EITHER SIDE OF THE AXIS W OF 47W.

...DISCUSSION...
THE GULF OF MEXICO...
THE MAIN FEATURE IN THE GULF IS AN UPPER LEVEL LOW WHICH IS NOW
CENTERED IN THE WRN GULF NEAR 26N94W. THIS LOW HAS BEEN TRACKING
FAIRLY QUICKLY ACROSS THE REGION...NEAR 20 KT. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE SPIRALING AROUND THE LOW MAINLY ON THE W
AND S SIDE OF THE CIRCULATION FROM 23N-30N W OF 93W. THERE ARE A
FEW WEAK SHOWERS THAT HAVE DEVELOPED ON THE E SIDE OF THE
CIRCULATION FROM 24N-26N BETWEEN 85W-87W. AS OF 2100 UTC...THE
UPPER LOW APPEARS TO BE BUILDING TO THE SFC WITH A FEW
BUOYS/SHIPS SHOWING SOME CYCLONIC WIND SHIFT IN THE AREA. THIS
SFC REFLECTION IS ANALYZED AS A TROF WITH THE AXIS ALONG 94W
FROM 24N-27N. THE REMAINDER OF THE EAST AND CENTRAL GULF IS
DOMINATED BY UPPER LEVEL DRY STABLE AIR LIMITING ANY SHOWER
ACTIVITY TO ISOLATED. AT THE SURFACE...HIGH PRES RIDGING FROM
THE ATLC HAS BUILT ACROSS THE GULF OF MEXICO WITH A 1018 MB HIGH
CENTER NEAR 28N85W. THIS PATTERN IS KEEPING WINDS RATHER LIGHT
AND GENERALLY FROM THE S-SE. THE GREATEST CHANCE OF RAIN
TOMORROW WILL CONTINUE TO BE IN THE FAR W GULF IN THE VICINITY
OF THE UPPER LOW....WHICH SHOULD BE INLAND OVER TEXAS/MEXICO AT
THIS TIME TOMORROW. FAIRLY DRY AIR WILL REMAIN ABOVE MUCH OF THE
AREA ALLOWING MOSTLY FAIR WEATHER TO CONTINUE ON FRI.

THE CARIBBEAN SEA...
THE EASTERN CARIBBEAN TROPICAL WAVE THAT SHOWED SOME POTENTIAL
FOR DEVELOPMENT YESTERDAY HAS GREATLY DIMINISHED TODAY. THIS
WAVE BASICALLY CONSISTS OF ONLY DISORGANIZED SCATTERED SHOWERS
WHICH LIE FROM 11N-19N BETWEEN 60W-70W. THIS SYSTEM WAS LIKELY
HIGHLY SHEARED AND INTRUDED BY DRY AIR FROM AN UPPER LEVEL LOW
TO THE N OF THE NRN LEEWARD ISLANDS CENTERED NEAR 21N63W. MORE
CONVECTIVE WEATHER IS IN THE SW CARIBBEAN AND ACROSS CENTRAL
AMERICA WHERE SCATTERED MODERATE CONVECTION LIES FROM 11N-18N
BETWEEN 80W-86W. THIS ACTIVITY HAS BEEN SURGING WESTWARD OVER
THE LAST COUPLE OF DAYS WITHIN EASTERLY FLOW AND IS NOW BEING
ENHANCED BY UPPER DIFFLUENCE BETWEEN THE GULF OF MEXICO UPPER
LOW AND AN UPPER HIGH CENTERED NEAR COSTA RICA. THE REMAINDER OF
THE CARIBBEAN IS UNDER A BROAD ATLC UPPER TROUGH WITH MAINLY DRY
AIR. IN THE LOWER LEVELS...15 TO 25 KT EASTERLY TRADE FLOW
CONTINUES TO DOMINATE MUCH OF THE CARIBBEAN THIS EVENING...DUE
TO THE INTERACTION BETWEEN THE ATLC HIGH NORTH OF THE AREA WITH
THE COLOMBIAN LOW. THE STRONGEST WINDS ARE LOCATED BETWEEN THE
COLOMBIAN/VENEZUELAN COASTS AND PUERTO RICO/HISPANIOLA DUE TO
THE TIGHTER PRES GRADIENT AND PERHAPS SOME ENHANCEMENT BY THE
APPROACHING TROPICAL WAVE. SOME MOISTURE ASSOCIATED WITH THE
WAVE WILL SPREAD TOWARDS THE CENTRAL AND WRN CARIBBEAN FRI AND
SAT.

THE ATLANTIC OCEAN...
THE ATLC OCEAN IS FAIRLY QUIET THIS EVENING WITH AN UPPER LEVEL
RIDGE/TROUGH/RIDGE PATTERN ACROSS THE AREA. A LARGE UPPER
LEVEL RIDGE IS WELL ESTABLISHED ACROSS THE U.S. EXTENDING INTO
THE WRN ATLC OUT TO 73W. A STATIONARY FRONT LIES TO THE N OF THE
DISCUSSION AREA ALONG 33N W OF 65W LEADING INTO A COLD FRONT
FARTHER EAST EVENTUALLY WRAPPING INTO A HIGH LATITUDE LOW. THIS
FRONTAL BOUNDARY IS GENERATING A LINE OF CLOUDINESS AND
SCATTERED SHOWERS N OF 28N W OF 50W. SOME OF THE GLOBAL MODELS
INDICATE THAT THIS FRONT WILL BE SINKING SWARD INTO THE
DISCUSSION AREA THIS WEEKEND. A BROAD UPPER TROUGH COVERS A GOOD
PORTION OF THE CENTRAL ATLC WITH THE AXIS EXTENDING FROM A WEAK
UPPER LOW NEAR 32N44W SWWARD TO AN UPPER LOW N OF THE VIRGIN
ISLANDS NEAR 20N63W. VERY LITTLE SHOWER ACTIVITY IS ASSOCIATED
WITH THESE UPPER LOWS...IN FACT...FAIRLY DRY STABLE AIR IS
WIDESPREAD UNDER THE TROUGH. THE REMAINDER OF THE ATLC IS
DOMINATED BY AN UPPER RIDGE WITH THE HIGH CENTER NEAR 17N38W.
WIDESPREAD DRY UPPER LEVEL AIR IS UNDER THE UPPER RIDGE LIMITING
ANY SHOWER ACTIVITY TO VERY ISOLATED. AT THE SURFACE...A NARROW
RIDGE IS THE THEME WITH THREE SMALL HIGH PRESSURE CENTERS
ANALYZED AT 1021 MB NEAR 28N32W...1019 MB NEAR 25N54W AND 1019
MB NEAR 26N68W...WITH THE RIDGE AXIS EXTENDING W THROUGH CENTRAL
FLORIDA.

$$
CANGIALOSI




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