[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE 12 APR 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N10W 4N20W 3N40W 8N60W. ISOLATED
MODERATE CONVECTION WITHIN 30 NM OF LINE FROM 5N8W TO 4N20W.
LARGE CLUSTER OF DISSIPATING SCATTERED SHOWERS/TSTMS FROM 1N-6N
BETWEEN 20W-28W. WIDELY SCATTERED SHOWERS/TSTMS WITHIN 45 NM OF
THE AXIS BETWEEN 46W-53W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS ACROSS THE CNTRL TO SW GULF OF MEXICO
WATERS ALONG A LINE FROM NEAR PENSACOLA FL TO 24N93W...THEN AS A
STATIONARY FRONT S INTO THE BAY OF CAMPECHE AND ALONG THE E
SLOPES OF THE SIERRA MADRES. VISIBLE IMAGERY AND SFC OBS ALSO
INDICATE THAT A WEAK 1007 MB LOW HAS FORMED JUST AHEAD OF THE
FRONT OVER THE BAY OF CAMPECHE NEAR 20N93W. HOWEVER...THE MAIN
MID/UPPER LEVEL ENERGY IS LOCATED WELL TO THE N WITH A CLOSED
UPPER LOW OVER THE STATE OF MISSOURI...SO THE BEST DYNAMICS FOR
PRECIP IS LOCATED OVER THE N GULF WATERS. WIDELY SCATTERED
SHOWERS/TSTMS EXTEND UP TO 75 NM E OF THE FRONT N OF 26N WITH
ONLY SCATTERED LOW/MID LEVEL CLOUDS WITHIN 120 NM OF THE FRONT
ELSEWHERE S OF 26N WHERE THE UPPER FLOW IS PREDOMINANTLY
WESTERLY AND DRYING. THE FRONT WILL CROSS THE E GULF AND FLORIDA
BY WED AFTERNOON/EVENING WITH WIDELY SCATTERED CONVECTION
REMAINING GENERALLY N OF A TAMPA BAY-CAPE CANAVERAL LINE. A
SECOND FRONT WILL MOVE OFF THE N GULF COAST LATE WED WITH A
REINFORCING SHOT OF DRIER AIR...BUT THE PRECEDING AIR MASS WILL
BE TOO DRY TO SUPPORT FRONTAL PRECIPITATION.

CARIBBEAN...
BRISK WESTERLY FLOW IN THE UPPER LEVELS EXTENDS ACROSS THE
ENTIRE CARIBBEAN BASIN WITH ONLY A FEW WISPS OF CIRRUS STREAMING
ACROSS THE SRN HALF OF THE BASIN DERIVED FROM CONVECTION OVER
SOUTH AMERICA. DRY AIR IN THE MID/UPPER LEVELS IS SUPPRESSING
ALL DEEP CONVECTION ALTHOUGH A WEAK LOW-LEVEL DISTURBANCE
EMBEDDED IN THE EASTERLY TRADES IS TRIGGERING A FEW SHOWERS
ABOUT 90 NM S OF HISPANIOLA. IN ADDITION...AN OLD FRONTAL TROF
IS DRAPED ACROSS PUERTO RICO TO THE DOMINICAN REPUBLIC AND IS
PRODUCING SCATTERED SHOWERS ACROSS THE E HALF OF HISPANIOLA.

ATLANTIC...
A STRONG MID/UPPER LEVEL LOW IS LOCATED WELL N OF THE AREA NEAR
NOVA SCOTIA/NEW BRUNSWICK WITH THE ASSOCIATED NEGATIVELY-TILTED
TROF EXTENDING INTO THE AREA ALONG 30N60W 23N56W. HIGH PRES IS
BUILDING OFF THE EASTERN U.S. COAST AND IS PUSHING A WEAK COLD
FRONT SWD TO ALONG 29N OVER THE W ATLC...WHILE AN OLD FRONTAL
TROF IS LOCATED FARTHER E ALONG 32N53W 20N62W. DIFFLUENCE AHEAD
OF THE UPPER TROF IS PRODUCING WIDELY SCATTERED SHOWERS/TSTMS
WITHIN 200 NM E OF THE SFC TROF N OF 22N. FARTHER E...AN
AMPLIFIED MID/UPPER RIDGE IS DRIFTING EWD ALONG 45W WITH CIRRUS
OUTFLOW FROM THE CNTRL ATLC SHOWERS/TSTMS MOVING E TO 40W. A
LARGE UPPER LOW IS CENTERED JUST SW OF MADEIRA ISLAND NEAR
32N22W WITH TROUGHING EXTENDING SWD TO THE CAPE VERDE ISLANDS
BETWEEN THE AFRICAN COAST AND 35W. A WEAK SFC TROF IS REFLECTED
AT THE SFC ALONG 32N37W TO 27N30W WITH BROKEN STRATOCU MOVING IN
FROM THE N BUT ERODING BEFORE THEY CROSS 30N. THE MOST
EYE-STRIKING FEATURE IS A LARGE AREA OF SAHARAN DUST MOVING OFF
THE COAST OF AFRICA E OF A LINE FROM 30N19W 20N25W 10N37W.

$$
BERG


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