[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 241756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUL 24 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE HAS BEEN ADDED ALONG 35W S OF 16N. THERE IS A
CLEAR REGION OF LOW TO MID LEVEL CYCLONIC TURNING NOTED FROM
10N-16N BETWEEN 33W-40W. THIS TURNING WAS FOCUSED AROUND 29/30W
AT 1200 UTC YESTERDAY WHICH MEANS THE WAVE IS MOVING W ABOUT 15
KT.  DEEP CONVECTION IS MINIMAL ASIDE FROM THE SCATTERED
MODERATE THAT IS CONFINED TO THE INTERSECTION OF THE WAVE AXIS
AND THE ITCZ FROM 6N-10N BETWEEN 30W-40W.

TROPICAL WAVE IS ALONG 49/50W S OF 20N MOVING W 20-25 KT. A
BROAD INVERTED V SHAPE REMAINS EVIDENT IN THE SURROUNDING BROKEN
STRATOCUMULUS FIELD FROM 14N-21N BETWEEN 45W-53W. DEEP
CONVECTION REMAINS MINIMAL.

CARIBBEAN TROPICAL WAVE IS ALONG 77W S OF 20N MOVING W NEAR 20
KT. SOME CYCLONIC TURNING NOTED IN THE LOWER CLOUD FIELD JUST
SSW OF JAMAICA. SCATTERED SHOWERS/ISOLATED TSTMS ARE FROM
13N-20N BETWEEN 75W-83W. ANOTHER AREA OF SCATTERED MODERATE
CONVECTION IS FURTHER E FROM 13N-17N BETWEEN 68W-74W...JUST S OF
HISPANIOLA...IN A REGION OF LOW LEVEL CONFLUENCE TRAILING THE
WAVE. A SMALLER CLUSTER OF SCATTERED MODERATE IS JUST N OF
PANAMA NEAR 10N79W.

TROPICAL WAVE IS OVER THE BAY OF CAMPECHE ALONG 94W S OF 21N
MOVING W 10-15 KT. SCATTERED MODERATE CONVECTION IS BETWEEN THE
WAVE AXIS AND THE YUCATAN PENINSULA...BUT THIS MAY BE MORE
ASSOCIATED WITH DIFFLUENCE AHEAD OF THE UPPER TROUGH OVER THE
GULF. A BIT MORE CONVECTION IS OVER THE EPAC PORTION OF THE WAVE
AS DESCRIBED IN THE PACIFIC DISCUSSION UNDER AWIPS HEADER
MIATWDEP.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N16W 11N32W 9N38W 10N48W 10N54W
7N60W. ISOLATED CLUSTERS OF MODERATE CONVECTION ARE OFF THE
AFRICAN COAST AND INLAND FROM 6N-14N E OF 20W. SCATTERED
MODERATE IS WITHIN 60NM N AND 120NM S OF THE AXIS BETWEEN
20W-30W...AND ALSO NEAR THE COAST OF SOUTH AMERICA FROM 6N-10N
BETWEEN 58W-63W.

...DISCUSSION...
GULF OF MEXICO...
THE REMNANTS OF A COMPLEX FRONTAL SYSTEM CONTINUES TO PRODUCE
MESSY WEATHER ESPECIALLY OVER THE NE GULF THIS AFTERNOON. AS OF
24/1500 UTC...A 1014 MB LOW IS JUST OFF THE
MISSISSIPPI/LOUISIANA COAST NEAR 30N89W. A TROUGH EXTENDS E FROM
THE LOW THROUGH 30N85W TO THE NRN W COAST OF FL NEAR 29N83W.
ANOTHER TROUGH EXTENDS SW/WSW FROM THE LOW TO 28N94W. ASSOCIATED
NUMEROUS SHOWERS/TSTMS ARE MAINLY S OF THE LOW/TROUGHS AND N OF
24N. THIS ACTIVITY IS ALSO BEING SUPPORTED BY LIFT AHEAD OF AN
ELONGATED UPPER TROUGH EXTENDING SW FROM ERN LOUISIANA TO
CENTRAL MEXICO. AN ATLC SFC RIDGE WILL GRADUALLY BUILD W ACROSS
THE GULF OVER THE NEXT COUPLE OF DAYS...BUT SUSPECT CONVECTION
WILL BE SLOW TO DIMINISH WITH THE UPPER TROUGH OVER THE AREA
DRIFTING SLOWLY NW.

CARIBBEAN SEA...
THE TROPICAL WAVE ALONG 77W IS RESPONSIBLE FOR MOST OF THE
ACTIVITY IN THE CARIBBEAN THIS AFTERNOON. A LARGE ANTICYCLONE
DOMINATES THE UPPER PATTERN...CENTERED IN THE NW CARIB NEAR
19N83W. NE FLOW E OF THIS UPPER HIGH HAS DEBRIS MOISTURE OVER
THE TROPICAL WAVE CONVECTION IN THE CENTRAL CARIB SPREADING SW.
A WEAK INVERTED UPPER TROUGH IS OVER THE FAR ERN PORTION OF THE
BASIN. TRADES ARE PRESENTLY LIGHT TO MODERATE BUT
EXPECTED TO INCREASE SLIGHTLY ESPECIALLY IN THE CENTRAL
CARIBBEAN OVER THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...
UPPER FLOW REMAINS WIDELY DIFFLUENT ACROSS THE WRN ATLC THIS
AFTERNOON...BETWEEN THE LARGE UPPER LOW/TROUGH OVER THE ERN U.S.
AND AN UPPER RIDGE EXTENDING NE FROM THE CARIBBEAN. THIS IS
SUPPORTING THE SCATTERED SHOWERS AND TSTMS OVER MUCH OF THE AREA
N OF 24N AND W OF 71W. WEAK SFC TROUGHING IN THIS VICINITY
ASSOCIATED WITH AN OLD FRONTAL SYSTEM ALSO SUPPORTS THE
ACTIVITY. A COUPLE OTHER CLUSTERS OF MODERATE CONVECTION ARE IN
THE LOW LEVEL CONFLUENT ZONE N OF 26N BETWEEN 62W-67W. A WEAK
SFC TROUGH IS IN THE CENTRAL ATLC ALONG 31N52W 22N54W...THAT IS
BEING TRAILED BY A LARGE POLEWARD INFLECTION OF SAHARAN DUST
BETWEEN 35W-51W. THE TROUGH IS EMBEDDED IN THE MODERATE ELY FLOW
S OF A 1029MB HIGH NEAR 37N43W...AND IS UNDERNEATH AN UPPER LOW
NEAR 26N52W. OVERALL FAIR WEATHER WITH TYPICAL PATCHES OF
STRATOCUMULUS CLOUDS ARE N OF 15N E OF 50W. LARGE SCALE UPPER
RIDGING DOMINATES THE ERN ATLC. EMBEDDED CYCLONIC TURNING NOTED
NEAR 25N33W AND 27N18W...BUT THESE FEATURES ARE BENIGN.

$$
WILLIS




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