[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU APR 13 2006

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0530 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N10W 2N20W EQ30W EQ40W 2S45W.
A SMALL CLUSTER OF MODERATE CONVECTION HAS FORMED WITHIN 50 NM
OF THE AXIS BETWEEN 17W-18W. OTHERWISE...ISOLATED/SCATTERED
SHOWERS ARE WITHIN 250 NM OF THE AXIS. THE MOST ORGANIZED
ACTIVITY IS MAINLY S OF THE AXIS BETWEEN 20W-35W.

...DISCUSSION...

THE GULF OF MEXICO...
MID-UPPER LEVEL RIDGING COVERS MEXICO...THE CENTRAL U.S. AND
MUCH OF THE GULF OF MEXICO. HIGH LEVEL MOISTURE IS FAIRLY
WIDESPREAD ACROSS MUCH OF THE AREA EXCEPT FOR THE SE CORNER
WHERE STRONG SUBSIDENCE IS HOLDING ON. THIS UPPER LEVEL MOISTURE
IS ADVECTED FROM THE EPAC ACROSS MEXICO AND THEN SSWARD ON THE E
SIDE OF THE RIDGE IN THE GULF. A FEW SHOWERS MAY BE EMBEDDED IN
THIS MOISTURE ESPECIALLY N OF 26N. AT THE SURFACE...A RIDGE
DOMINATES THE AREA PRODUCING GENERALLY FAIR WEATHER. SURFACE
HIGH PRESSURE IS EXPECTED TO REMAIN IN CONTROL ACROSS THE AREA
THRU FRI. THEREAFTER...THE HIGH PRES SYSTEMS WILL MOVE TO THE
EAST OF THE REGION ALLOWING S/SW RETURN FLOW TO DEVELOP POSSIBLE
ENHANCING SOME SHOWER ACTIVITY IN THE N GULF OVER THE WEEKEND.

THE CARIBBEAN SEA AND THE ATLANTIC OCEAN WEST OF 60W...
AN UPPER TROUGH TO THE E OF THE GULF RIDGE HAS BEEN STUCK IN THE
NW CARIBBEAN MUCH OF THE WEEK. THIS TROUGH APPEARS TO HAVE
BECOME SOME-WHAT CUT-OFF IN THE AREA. A 1011 MB SFC LOW IS
LOCATED IN THE E BAHAMAS NEAR 22N71W AND SITS ON A STATIONARY
FRONT WHICH EXTENDS NEWD FROM THE LOW TO BEYOND 32N56W. AN UPPER
LOW IS CENTERED TO THE W OF THE SFC LOW IN THE CENTRAL BAHAMAS.
UPPER LEVEL DIVERGENCE AND SFC FORCING IS PRODUCING A SHIELD OF
OVERCAST SKIES...SCATTERED SHOWERS AND POSSIBLE TSTMS FROM
21N-32N BETWEEN 59W-73W. THE MOST ORGANIZED SHOWER ACTIVITY IS
WITHIN 200 NM OF THE STATIONARY FRONT AND THE NEAR THE UPPER LOW
N OF CUBA. A SFC TROUGH IS DRAPED FROM THE LOW SWD OVER
HISPANIOLA. SAN JUAN DOPPLER RADAR INDICATES A BATCH OF SOLID
MODERATE RAIN WITH EMBEDDED TSTMS TO THE W OF THE ISLAND.
CONSIDERABLE MOISTURE IS DRAWN NWD FROM THE EPAC AND S AMERICA
ON THE E SIDE OF THE TROUGH AXIS AND IS RACING NEWARD MOVING
INTO THE DEEP MOISTURE N OF THE CARIBBEAN ISLANDS. VERY
DRY/STABLE AIR IS TO THE W OF THE TROUGH AXIS ACROSS THE NW
CARIBBEAN KEEPING SKIES MOSTLY CLEAR FROM CUBA TO NICARAGUA.
GFS SUGGESTS THAT THE SFC LOW WILL BEGIN TO PULL NEWARD THU
NIGHT AS THE UPPER TROUGH BEGINS TO FLATTEN. THE UNSETTLED
WEATHER WILL CONTINUE TO SHIFT SLIGHTLY EWD TOMORROW BEFORE
BECOME SOMEWHAT DIFFUSE BY THE WEEKEND. THE DEEPEST MOISTURE
WILL CONTINUE TO BE MAINLY TO THE N OF THE ISLANDS.

THE REST OF THE ATLANTIC OCEAN...
A RIDGE/TROUGH/RIDGE UPPER LEVEL PATTERN DOMINATES THE REMAINDER
OF THE ATLANTIC OCEAN. A RATHER BROAD FLATTENING RIDGE STRETCHES
FROM S AMERICA TO BEYOND 32N48W. SCATTERED STRATOCUMULUS CLOUDS
ARE FAIRLY WIDESPREAD UNDER THE RIDGE. AN DEEP-LAYER TROUGH
COVERS A GOOD PORTION OF THE CENTRAL AND EASTERN ATLC
WATERS...NAMELY FROM 20W-40W N OF 20N. THE ONLY SFC FEATURE TO
MENTION IN THE AREA IS A 1016 MB LOW UNDERNEATH THE UPPER
TROUGH. THERE ARE SOME SCATTERED SHOWERS SPIRALING AROUND THE
LOW MOSTLY WITHIN 200 NM OF THE CENTER. AN 80-100 KT SWLY JET
ORIGINATES ON THE S SIDE OF THE UPPER LOW AND STRETCHES TO N
AFRICA NEAR 34N6W. UPPER LEVEL DIFFLUENCE IS PRODUCING AN AREA
OF SHOWERS AND TSTMS TO THE RIGHT OF THE AXIS FROM 24-33N
BETWEEN 13W-23W. THIS UPPER LOW IS EXPECTED TO RACE NEWARD
LEAVING A NEAR ZONAL WESTERLY UPPER LEVEL PATTERN ACROSS THE
CENTRAL AND E ATLC BY SAT. A RATHER LARGE UPPER HIGH IS LOCATED
TO THE S OF THE DEEP-LAYER TROUGH OVER W AFRICA WITH PLENTY OF
DRY AIR ALOFT OVER THE W PART OF THE CONTINENT BETWEEN 7N-18N.
BROAD WEAK RIDGING EXISTS IN THE TROPICAL ATLC LIMITING
CONVECTION IN THE ITCZ.

$$
CANGIALOSI


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