[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN 08 MAY 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ABOUT 400 NM W OF THE CAPE VERDE ISLANDS ALONG 32W
S OF 14N MOVING W 10-15 KT. TIMESECTIONS FROM DAKAR AND SAL
SUGGESTED A WEAK WAVE PASSAGE ABOUT TWO DAYS AGO...AND SATELLITE
IMAGERY INDICATES A SURGE OF LOW-LEVEL MOISTURE MOVING NWWD OUT
OF THE ITCZ BETWEEN 29W-35W. ISOLATED MODERATE CONVECTION NEAR
THE AXIS IS ASSOCIATED WITH THE ITCZ.

TROPICAL WAVE CENTERED S OF HISPANIOLA ALONG 70W S OF 16N MOVING
W ABOUT 10 KT. THE 24-HR MOVEMENT OF THE WAVE APPEARS TO HAVE
SLOWED DOWN A BIT AS MOVES THROUGH A WEAKER PRES GRADIENT DUE TO
THE FRONT LOCATED OVER THE W ATLC. ISOLATED SHOWERS HAVE BEEN
OCCASIONALLY POPPING E OF THE AXIS FROM 14N-17N BETWEEN 68W-71W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 5N24W 6N30W...THEN ALONG 4N33W
1N50W. WIDELY SCATTERED MODERATE CONVECTION WITHIN 100 NM N AND
220 NM S OF THE AXIS BETWEEN 15W-28W. WIDELY SCATTERED MODERATE
WITHIN 90 NM N AND 150 NM S BETWEEN 33W-39W. NUMEROUS MODERATE
WITHIN 120 NM BETWEEN 40W-51W.

...DISCUSSION...

GULF OF MEXICO...
BROAD HIGH PRES AT THE SFC HAS SETTLED IN ACROSS THE NE GULF AND
FLORIDA AND HAS BROUGHT IN A DRIER AIR MASS OVER THE AREA WITH
DEWPOINTS DROPPING INTO THE LOWER 60S TO THE LOW/MID 50S EVEN
OVER THE E GULF WATERS. HOWEVER...THE HIGH HAS SHIFTED FAR
ENOUGH TO THE E TO ALLOW MOIST RETURN FLOW TO SET UP OVER THE W
GULF INTO TEXAS AND NE MEXICO WHERE DEWPOINTS ARE NOW PUSHING
70F. VISIBILITIES IN THE AREA HAVE NOT FALLEN ENOUGH TO SUPPORT
FOG DEVELOPMENT BUT CEILINGS OVER S TEXAS HAVE DROPPED TO ABOUT
1500 FT WITH PATCHY DRIZZLE DUE TO THE MOIST AIR MASS. IN
ADDITION...AREAS OF SMOKE CONTINUE TO DRIFT ACROSS THE BAY OF
CAMPECHE UP THE E COAST OF MEXICO...AND THESE PARTICULATES ARE
ENHANCING THE DEVELOPMENT OF THE LOW CLOUDS. UPPER LEVEL
WESTERLY FLOW RUNS ACROSS THE REGION WITH SOME HIGH CLOUDINESS
ZIPPING ACROSS THE BAY OF CAMPECHE ALONG THE SUBTROPICAL
JET...BUT A RIDGE EXTENDING FROM THE N/CNTRL GULF UP THE
MISSISSIPPI VALLEY IS HELPING TO PRODUCE MOSTLY DRY AND TRANQUIL
CONDITIONS ACROSS THE REST OF THE AREA. THERE IS NO SIGNIFICANT
PATTERN CHANGE EXPECTED THROUGH THE MIDDLE OF THE WEEK...SO
GENERALLY DRY CONDITIONS WILL CONTINUE WITH LOW CLOUDS/DRIZZLE
STILL OCCURRING ACROSS SE TEXAS AND NE MEXICO. AREAS OF SMOKE
ORIGINATING FROM SRN MEXICO MAY ALSO BE PICKED UP IN THE
LOW-LEVEL FLOW AND BROUGHT IN OVER NE MEXICO AND S TEXAS.

CARIBBEAN...
A WEAK UPPER LEVEL TROF/SHEAR AXIS HAS SET UP OVER THE W
CARIBBEAN FROM THE WINDWARD PASSAGE TO JAMAICA TO NICARAGUA WITH
SWLY FLOW TO THE E OF THIS FEATURE DRAGGING LARGE AMOUNTS OF
TROPICAL MOISTURE NEWD ACROSS THE CNTRL CARIBBEAN AND
HISPANIOLA. THE LARGE CLUSTER OF TSTMS THAT HAD DEVELOPED OVER
THE SW CARIBBEAN EARLIER TODAY APPEARS TO HAVE MOSTLY DISSIPATED
AND HAS LEFT BEHIND A MID-LEVEL CIRCULATION WITH ISOLATED
SHOWERS/TSTMS FROM 11N-14N BETWEEN 78W-83W. OTHER ISOLATED
SHOWERS HAVE BEEN DEVELOPING OVER THE HIGH TERRAIN OF HISPANIOLA
AS THE MOIST SWLY FLOW IMPINGES UPON IT. ELSEWHERE...BOTH THE NW
AND E CARIBBEAN ARE COVERED BY RELATIVELY DRY AIR MASSES...AND
ONLY A FEW LOW-LEVEL TRADE SHOWERS ARE NOTED MOVING ACROSS
ANTIGUA...GUADELOUPE...AND DOMINICA. ALSO...A LARGE CLUSTER OF
NUMEROUS MODERATE/STRONG CONVECTION IS LOCATED OVER NW COLOMBIA
FROM 3N-11N BETWEEN 71W-78W. MOISTURE VALUES ARE EXPECTED TO
INCREASE OVER THE ENTIRE AREA OVER THE NEXT SEVERAL DAYS WHICH
WILL INCREASE THE LIKELIHOOD OF SHOWERS/TSTMS.

ATLANTIC...
THE STRONG COASTAL NOR'EASTER THAT HAS BEEN AFFECTING THE U.S.
EAST COAST IS NOW LOCATED ABOUT 200 NM SE OF CAPE COD BUT THE
ASSOCIATED UPPER TROF SAGS DOWN TO ABOUT 25N WITH A LARGE AREA
OF DRY AIR SWEEPING OVER THE W ATLC WATERS. A COLD FRONT ENTERS
THE AREA E OF BERMUDA ALONG 32N63W 23N70W AND DIFFLUENCE ALOFT E
OF THE TROF IS PRODUCING WIDELY SCATTERED MODERATE CONVECTION N
OF 25N BETWEEN 56W-64W. A RIDGE IS CENTERED FARTHER DOWNSTREAM
ALONG 50W AND IS PUSHING MOST OF THE UPPER LEVEL MOISTURE N OF
THE AREA...LEAVING A LARGE AREA OF MODERATE/STRONG SUBSIDENCE
FROM 10N-26N BETWEEN 20W-60W. AN UPPER TROF LIES ALONG THE
LEADING EDGE OF THIS DRY AIR ALONG 32N24W 20N25W 13N40W WITH A
100 KT JET LIFTING NEWD ACROSS THE CANARY ISLANDS. THIS IS
PULLING HIGH CLOUDS OUT OF THE TROPICS NEWD TOWARDS THE CANARIES
AND THE MOROCCAN COAST. AN UPPER LEVEL ANTICYCLONE IS EMBEDDED
DEEP WITHIN THE TROPICS NEAR 7N26W WITH A RIDGE AXIS EXTENDING
EWD TOWARDS GUINEA AND SIERRA LEONE...AND WWD ALONG THE N COAST
OF S AMERICA TO FRENCH GUIANA.

$$
BERG


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