[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 18 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 BROAD E ATLC TROPICAL WAVE IS ALONG 18N30W 6N32W. A 1012 MB
LOW IS ALONG THE WAVE AXIS NEAR 14N MOVING W NEAR 18 KT. THE LOW
ITSELF CONSISTS OF ELONGATED CYCLONIC TURNING IN BROKEN
STRATOCUMULUS. SCATTERED MODERATE CONVECTION IS LIMITED TO THE
INTERSECTION OF THE WAVE AXIS AND THE ITCZ GENERALLY FROM 7N-11N
BETWEEN 30W-37W.

TROPICAL WAVE IS ALONG 58W S OF 17N MOVING W 15-20 KT. THIS WAVE
CONTINUES TO EXHIBIT A BROAD INVERTED V SHAPE. UPPER E/SE FLOW S
OF AN UPPER HIGH IS DISPLACING MOST OF THE ASSOCIATED CONVECTION
TO THE W OF THE AXIS. THIS SCATTERED MODERATE CONVECTION IS
AFFECTING THE SRN WINDWARD ISLANDS AND ADJACENT WATERS FROM
10N-16N BETWEEN 57W-64W. ANOTHER CLUSTER OF MODERATE CONVECTION
IS WITHIN 90NM E OF THE AXIS FROM 8N-10N.

TROPICAL WAVE IS ALONG 85/86W S OF 19N MOVING W NEAR 15 KT.
SCATTERED MODERATE CONVECTION IS MOVING TOWARDS THE GULF OF
HONDURAS WITHIN 200NM E OF THE AXIS N OF 15N. A SIMILAR PATCH OF
CONVECTION IS MOVING ONSHORE THE SRN COAST OF NICARAGUA. THIS
WAVE ALSO EXTENDS INTO THE FAR NE PACIFIC AS DESCRIBED IN THE
PACIFIC DISCUSSION UNDER AWIPS HEADER MIATWDEP.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N16W 14N22W 11N29W 7N45W 12N55W.
ISOLATED MODERATE CONVECTION IS JUST OFF THE COAST OF AFRICA
FROM 9N-13N E OF 18W. NUMEROUS MODERATE/ISOLATED STRONG IS FROM
7N-10N BETWEEN 46W-50W...AND FROM 6N-10N BETWEEN 51W-55W.

...DISCUSSION...
GULF OF MEXICO...
THE MOST ACTIVE WEATHER CONTINUES TO BE IN THE WRN PORTION.
NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS OFF AND ALONG
THE NE MEXICO COAST FROM 21N-25N W OF 96W. SCATTERED MODERATE IS
ALSO AFFECTING COASTAL TEXAS N OF 25N W OF 96W. ALTHOUGH SOME
WEAK SFC TROUGHING IS EVIDENT IN THE WRN GULF...MOST OF THE
SUPPORT FOR THIS ACTIVITY LIES ALOFT WITH DIFFLUENT FLOW BETWEEN
THE UPPER LOW OVER NRN MEXICO AND AN UPPER HIGH OVER THE CENTRAL
GULF NEAR 26N91W. ISOLATED SHOWERS/TSTMS UNDER THE UPPER HIGH
ALSO DOT THE REMAINDER OF THE GULF FROM 24N-27N. A WEAK 1020 MB
HIGH IS JUST S OF PENSACOLA NEAR 29N87W. THIS LOOKS TO REMAIN
QUASI STATIONARY OVER THE NEXT COUPLE OF DAYS...KEEPING
LIGHT/VARIABLE WINDS IN THE NE PORTION AND LIGHT TO MODERATE
E/SE FLOW IN THE SW PORTION.

CARIBBEAN SEA...
ACTIVE WEATHER IS AFFECTING THE FAR W AND E PORTIONS OF THE
CARIBBEAN ASSOCIATED WITH THE TROPICAL WAVES AS DESCRIBED ABOVE.
THE AREA BETWEEN 70W-80W IS UNDER MOSTLY CLEAR SKIES WITH ONLY A
FEW PATCHES OF LOW LEVEL MOISTURE BEING CARRIED WWD BY THE
MODERATE TO FRESH TRADES IN PLACE. THE UW-CIMSS SAHARAN AIR
LAYER PRODUCT ALSO DEPICTS A FAIRLY DENSE REGION OF DUST IN THIS
VICINITY OF THE CENTRAL CARIB. ISOLATED SHOWERS WITH A FEW
EMBEDDED TSTMS ARE AFFECTING WRN PUERTO RICO...ERN
HISPANIOLA...AND ADJACENT WATERS FROM 18N-20N BETWEEN 66W-70W.
THIS SEEMS MOSTLY ASSOCIATED WITH THE FAVORABLE DIFFLUENT
PATTERN ALOFT BETWEEN THE UPPER LOW JUST W OF JAMAICA AND AN
UPPER HIGH JUST E OF THE WINDWARD ISLANDS. SHOWERS/TSTMS
ASSOCIATED WITH THE TROPICAL WAVE JUST E OF THE WINDWARD ISLANDS
WILL PUSH THROUGH THE ERN CARIB OVER THE NEXT COUPLE OF DAYS.
OVERALL MODERATE TO FRESH TRADES TO PERSIST.

ATLANTIC OCEAN...
ISOLATED TSTMS ARE OVER THE FAR WRN ATLC N OF 27N W OF 77W
UNDERNEATH AN UPPER HIGH AND MOSTLY OVER THE GULF STREAM.
OVERALL THOUGH SFC RIDGING DOMINATES MUCH OF THE DISCUSSION AREA
S OF A 1032 MB HIGH PRES CENTER NEAR 37N48W. INVERTED SFC
TROUGHING EMBEDDED IN THIS RIDGE IS ALONG 30N64W 25N63W 21N67W.
THIS...ALONG WITH LIFT AHEAD OF THE MID TO UPPER LOW NEAR
27N66W...IS SUPPORTING SCATTERED SHOWERS/ISOLATED TSTMS N OF 20N
BETWEEN 58W-66W. THE AREA N OF 17N AND E OF 55W IS WIDELY
DOMINATED BY FAIR WEATHER...SCATTERED LOW TO MID CLOUDS AND
MODERATE TRADES. AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 18N57W
DOMINATES THE TROPICAL ATLANTIC WEST OF 40W WITH ANOTHER UPPER
RIDGE OVER THE FAR ERN ATLC. IN BETWEEN IS A WEAK UPPER TROUGH N
OF 18N BETWEEN 35W-50W. DENSE AREA OF AFRICAN DUST NOTED OVER
MUCH OF THE AREA E OF 50W.

$$
WILLIS


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