[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 161753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE AUG 16 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA... GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

HURRICANE IRENE CENTERED NEAR 36.7N 62.4W...OR 730 NM SW OF CAPE
RACE NEWFOUNDLAND...AT 16/1500 UTC MOVING E 9 KT. MAXIMUM
SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 983 MB. SEE THE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE
DETAILS. IRENE DEVELOPED AN EYE AROUND 1300 UTC THIS MORNING BUT
WESTERLY SHEAR HAS BEGUN TO OBSCURE THE FEATURE ONCE AGAIN. THE
SHEAR ALSO APPEARS TO HAVE BEGUN TO ERODE THE WRN SIDE OF THE
SYSTEM WITH THE CLOUD ENVELOPE CONTRACTING A BIT AND EXTENDING
NO MORE THAN 75 NM FROM THE CENTER. A RING OF TSTMS HAS JUST
ABOUT COMPLETELY ENCIRCLED THE CENTER WITH NUMEROUS MODERATE
CONVECTION WITHIN 75 NM OF THE EYE.

A 1011 MB LOW...PREVIOUSLY TROPICAL DEPRESSION TEN...IS CENTERED
NEAR 16N52W MOVING WNW 5-10 KT. THE LOW-LEVEL CENTER IS
CURRENTLY LOCATED UNDER THE S SIDE OF A BURST OF TSTMS...BUT THE
CONVECTIVE PATTERN HAS BEEN CHANGING ALL MORNING AND HAS NOT
BEEN CONDUCIVE FOR FURTHER DEVELOPMENT. THE LOW IS LOCATED ABOUT
300 NM E OF A LARGE UPPER LOW AND IS CONSEQUENTLY UNDER 10-20 KT
OF SWLY SHEAR...BUT THE ENVIRONMENT IS EXPECTED TO BECOME MORE
FAVORABLE FOR REGENERATION AND A TROPICAL DEPRESSION COULD
REFORM WITHIN 24-36 HRS. SCATTERED MODERATE CONVECTION IS FROM
16N-19N BETWEEN 48W-55W.

...TROPICAL WAVES...

TROPICAL WAVE NEAR THE COAST OF AFRICA IS SOMEWHAT TILTED FROM
THE WESTERN SAHARA/MAURITANIA BORDER SW TO NEAR 8N20W...MOVING W
5-10 KT. UPPER AIR DATA FROM DAKAR OVER THE PAST DAY OR SO HAS
INDICATED THAT A BACKWARD TILTED WAVE BEGAN MOVING OFF THE COAST
YESTERDAY MORNING. HOWEVER...VISIBLE IMAGERY INDICATES THAT THE
WAVE HAS YET TO FULLY EMERGE WITH BROAD S/SWLY FLOW FEEDING UP
INTO GUINEA-BISSAU...SENEGAL...AND WRN MAURITANIA. SURFACE
OBSERVATIONS INDICATE THAT A WEAK 1009 MB LOW IS LOCATED ALONG
THE AXIS NEAR THE SENEGAL/MAURITANIA BORDER...AND THIS FEATURE
IS EXPECTED TO MOVE SW 10-15 KT OVER THE NEXT 24 HRS. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 13N-19N BETWEEN
12W-19W...AND FARTHER SW ALONG THE ITCZ.

CENTRAL ATLANTIC TROPICAL WAVE ALONG 39W/40W S OF 21N MOVING W
15 KT. THE WAVE CONTINUES TO MARK THE LEADING EDGE OF AN AFRICAN
DUST SURGE...AND IS TILTED NW/SE DUE TO STRONGER TRADES NEAR THE
SUBTROPICAL HIGH. THERE IS NO ASSOCIATED DEEP CONVECTION WITH
THIS WAVE.

WEST CARIBBEAN TROPICAL WAVE ALONG TILTED FROM NICARAGUA AND
COSTA RICA ACROSS THE NW CARIBBEAN TO THE FLORIDA KEYS...MOVING
W 20 KT. VISIBLE IMAGERY INDICATES CYCLONIC CURVATURE IN THE
CLOUD FIELD STRETCHING FROM THE GULF OF HONDURAS INTO THE SE
GULF OF MEXICO WITH THE DEVELOPMENT OF SCATTERED TSTMS. THE WAVE
HAS A FAIRLY HIGH AMPLITUDE...AND WAS OBSERVED PASSING BOTH KEY
WEST AND MIAMI UPPER AIR SITES DURING THE EARLY MORNING HOURS.
WIDELY SCATTERED TSTMS FROM 15N-25N BETWEEN 83W-89W. SCATTERED
MODERATE CONVECTION OVER ERN NICARAGUA AND COSTA RICA FROM
9N-15N BETWEEN 82W-85W.

TROPICAL WAVE OVER THE BAY OF CAMPECHE AND SRN MEXICO ALONG 94W
S OF 21N MOVING W 15-20 KT. A BATCH OF SCATTERED MODERATE
CONVECTION HAS DEVELOPED OVER THE SW GULF OF MEXICO AND IS
MOVING INLAND ALONG THE COAST OF MEXICO NEAR VERACRUZ FROM
19N-23.5N BETWEEN 90W-97W.

...ITCZ...

ITCZ AXIS IS ALONG 14N17W 11N23W 11N32W 8N42W 17N50W...THEN
ALONG 10N75W 9N83W. SCATTERED MODERATE CONVECTION WITHIN 90 NM
OF THE AXIS BETWEEN 20W-30W. SCATTERED MODERATE FROM 6.5N-10N
BETWEEN 45W-50W. NUMEROUS MODERATE/STRONG FROM 8N-12N BETWEEN
70W-85W...INCLUDING OVER NRN COLOMBIA...PANAMA...AND COSTA RICA.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW IS SPINNING WWD OVER CNTRL MEXICO AND IS ATTACHED
TO A SECOND UPPER LOW OVER THE NE GULF WATERS NEAR 27N88W.
BROAD-SCALE UPPER LEVEL MOISTURE IS BEING PULLED N AND EWD ON
THE S SIDE OF THE CONNECTING TROF AND IS SPREADING FROM THE BAY
OF CAMPECHE TO THE SE GULF AND FLORIDA. A SERIES OF TRPCL WAVES
IS CURRENTLY BRUSHING BY THE AREA WITH ONE OVER THE BAY OF
CAMPECHE...AND THE OTHER MOVING THRU THE FLORIDA STRAITS. AS
SUCH...WIDELY SCATTERED MODERATE CONVECTION HAS DEVELOPED FROM
NEAR VERACRUZ MEXICO AND THE BAY OF CAMPECHE EXTENDING NEWD TO
NEAR KEY WEST FLORIDA. A FEW ISOLATED SHOWERS HAVE FORMED FROM
NEAR MOBILE ALABAMA TO OFF THE LOUISIANA COAST BUT OVERALL THE N
GULF IS UNDER THE INFLUENCE OF MAINLY CLEAR SKIES. LOW-LEVEL
MOISTURE WILL CONTINUE TO POOL OVER THE SW GULF OVER THE NEXT
COUPLE OF DAYS AS THE TRPCL WAVES MOVE BY...WITH A CONTINUED
CHANCE FOR SHOWERS/TSTMS NEAR THE MEXICAN COAST THRU THU.

CARIBBEAN...
A LARGE MID/UPPER LOW IS CENTERED OVER THE CNTRL CARIBBEAN NEAR
16N73W ABOUT 120 NM S OF HAITI. THE LOW IS PULLING BROAD NLY
FLOW OVER THE W HALF OF THE CARIBBEAN BASIN...AND AS A RESULT IS
PULLING A LARGE AREA OF CIRRUS OUTFLOW FROM W OF 80W SEWD TO THE
VENEZUELA COAST. DRY AIR FARTHER N OVER THE W ATLC IS BEING
DRAWN INTO THE CIRCULATION OF THE LOW AND HAS SPREAD OVER ERN
CUBA AND JAMAICA THEN S OF THE ACTUAL CENTER. ALTHOUGH THE LOW
IS CAUSING ISOLATED SHOWERS PRIMARILY ON ITS E SIDE...THE BULK
OF THE DEEP CONVECTION IS CURRENTLY OVER THE SW CARIBBEAN NEAR
THE ITCZ...AND WHERE THE UPPER FLOW IS DIVERGING TO THE E AND
SW. SHOWERS/TSTMS CURRENTLY OVER THE NW CARIBBEAN WILL MOVE W
OVER THE YUCATAN OVER THE NEXT 24 HRS AND WILL BE REPLACED BY
RELATIVELY DRY AIR AT LEAST THRU THU. THE E CARIBBEAN AND LESSER
ANTILLES WILL CONTINUE WITH RELATIVELY DRY CONDITIONS FOR
SEVERAL DAYS WITH ONLY A FEW PASSING TRADE SHOWERS.

ATLANTIC...
A LARGE UPPER LEVEL HIGH IS CENTERED SE OF THE CAROLINAS NEAR
32N75W AND IS PRODUCING BROAD E/NELY FLOW ACROSS THE W ATLC. THE
HIGH IS RESPONSIBLE FOR MOSTLY SUBSIDENT CONDITIONS SO THERE ARE
NO SHOWERS/TSTMS NOTED W OF 70W. A NEARLY STATIONARY UPPER LOW
IS CENTERED FARTHER E NEAR 31N48W...JUST TO THE E OF A
CORRESPONDING SFC LOW NEAR 31N54W. SCATTERED SHOWERS/TSTMS
EXTEND FROM 27N-32N BETWEEN 45W-54W MOSTLY IN THE VICINITY OF
THE UPPER LOW. A SFC TROF EXTENDS SW OF THE SFC LOW TO 20N67W
AND IS PRODUCING WIDELY SCATTERED MODERATE CONVECTION FROM
18N-24N BETWEEN 63W-70W. FARTHER SE...A LARGE MID/UPPER LOW IS
CENTERED NE OF THE LEEWARD ISLANDS NEAR 19N58W BUT IS PRODUCING
VERY LITTLE WEATHER DUE TO ITS ASSOCIATED SUBSIDENCE. THE LOW IS
PRODUCING SOME SWLY SHEAR ATOP FORMER T.D. 10 HOWEVER...AND MAY
CONTINUE BEING AN INHIBITING FACTOR AS THEY MOVE IN TANDEM TO
THE W. THE E ATLC IS DOMINATED BY A LARGE UPPER HIGH NEAR 22N34W
WITH A RIDGE EXTENDING FROM THE CANARY ISLANDS SW TO 17N50W. A
SURGE OF AFRICAN DUST IS LOCATED BENEATH THIS RIDGE AND EXTENDS
GENERALLY E OF 40W. MOISTURE IS BEGINNING TO INCREASE ALONG THE
AFRICAN COAST AS A NEW TRPCL WAVE EMERGES ALONG 17W/18W.

$$
BERG


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