[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 012352
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT 01 JAN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N1W 8N15W 5N35W 8N60W 9N70W 4N80W.
SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF W AFRICA
FROM 3N-6N BETWEEN 1W-4W.  ISOLATED MODERATE CONVECTION IS FROM
4N-7N BETWEEN 28W-35W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD MIDDLE TO UPPER LEVEL RIDGE WILL CONTINUE TO DOMINATE
THE GLFMEX AND E UNITED STATES FOR THE NEXT SEVERAL DAYS
RESULTING IN UPSTREAM MID-LATITUDE DISTURBANCES AND CONTINENTAL
AIR BEING CONFINED OVER THE CONUS.  THE MEAN RIDGE AXIS
CURRENTLY EXTENDS FROM THE BAY OF CAMPECHE NEWD ACROSS S FLORIDA
INTO THE W ATLC NEAR BERMUDA. MIDDLE TO UPPER LEVEL MOISTURE IS
RESTRICTED TO THE N OF THE RIDGE AXIS AS THE SUBTROPICAL JET AND
PACIFIC MOISTURE EXTENDS ACROSS NW MEXICO INTO THE CENTRAL
UNITED STATES.  AT THE SURFACE...STRONG HIGH PRES OVER THE SE
UNITED STATES CONTINUES TO PRODUCING MODERATE RETURN FLOW OVER
THE W GULF WITH INCREASING LOW LEVEL MOISTURE AND SHOWER
ACTIVITY OVER THE W GLFMEX COURTESY OF AN ELY DISTURBANCE MOVING
ACROSS THE YUCATAN PENINSULA INTO THE SE GULF.  SATELLITE
IMAGERY INDICATES THIS MOISTURE IS GETTING PULLED NWD TOWARD
TEXAS AND LOUISIANA AND SHOULD HELP SPARK SHOWERS/THUNDERSTORMS
OVER THE CENTRAL AND S UNITED STATES SUN AND MON AS IT INTERACTS
WITH A MID-LATITUDE WEATHER SYSTEM.

CARIBBEAN...
AN UPPER LEVEL TROUGH WITH STRONG SUBSIDENCE DOMINATES THE
CENTRAL AND WESTERN CARIBBEAN W OF 70W.  THE EASTERN CARIBBEAN E
OF 70W IS INFLUENCED BY THE WESTERN PORTION OF A LARGE RIDGE
OVER THE TROPICAL ATLANTIC FROM 1N-20N BETWEEN 25W-70W.  AT THE
SURFACE...THE LOW ELY DISTURBANCE WHICH BROUGHT UNSETTLED
WEATHER OVER THE W CARIBBEAN AND CENTRAL AMERICA YESTERDAY HAS
SHIFTED NW OF THE AREA INTO THE SE GLFMEX.  HOWEVER...STRONG NE
FLOW CONTINUES TO PRODUCE CLOUDINESS AND SHOWERS ALONG THE
WINDWARD FACING SLOPES OF CENTRAL AMERICA.  OVER THE E
CARIBBEAN...A PIECE OF ENERGY AND MOISTURE WHICH BROKE OFF OF
WEAK SFC TROF/REMNANT FRONTAL BOUNDARY OVER THE CENTRAL ATLC IS
MOVING ACROSS THE S CARIBBEAN AND PRODUCING SCATTERED SHOWERS
FROM 12N-15N BETWEEN 65W-75W. THIS ACTIVITY SHOULD CONTINUE TO
MOVE QUICKLY WESTWARD WITHIN THE ESTABLISHED ELY FLOW.
ELSEWHERE...A SECOND REMNANT FRONTAL BOUNDARY/TROUGH WITH
SCATTERED SHOWERS TRAILS SWD FROM THE CENTRAL ATLC INTO THE NE
CARIBBEAN NEAR BARBUDA TO THE SE TIP OF HISPANIOLA. THE BOUNDARY
AND ASSOCIATED SHOWER ACTIVITY IS PUSHING QUICKLY SWD WITH DRY
AIR TO THE NORTH FILTERING IN BEHIND.  FINALLY...A WEAK ELY
DISTURBANCE IS PRODUCING SCATTERED THUNDERSTORMS OVER THE S
WINDWARD ISLANDS AND TRINIDAD/TOBAGO.  THIS ACTIVITY SHOULD MOVE
SLOWLY WESTWARD AFFECTING THE N PORTIONS OF VENEZUELA AND
EXTREME SE CARIBBEAN OVER THE NEXT DAY OR TWO.

ATLANTIC...
THE PATTERN OVER THE W ATLC...N OF 20N AND W OF 60W...REMAINS
ESSENTIALLY UNCHANGED COURTESY OF A DEEP LAYERED RIDGE ANCHORED
OVER THE AREA.  THE MIDDLE TO UPPER LEVEL PORTION OF THE RIDGE
EXTENDS FROM S FLORIDA NEWD OVER BERMUDA WHILE THE SURFACE RIDGE
EXTENDS E/W ALONG 32N.  THE NEARLY STATIONARY SURFACE RIDGE
CONTINUES TO PRODUCE MODERATE TO STRONG NE WINDS S OF 26N.
CLOUDINESS AND WIDELY SCATTERED SHOWERS CONTINUE TO DOT THE AREA
BUT HAVE STEADILY DECREASED DURING THE LAST TWO DAYS.  MOISTURE
AND SHOWER ACTIVITY WILL BE ON THE INCREASE AGAIN TOWARD
MID-WEEK AS THE REMNANTS OF A FRONTAL BOUNDARY OVER THE CENTRAL
ATLC BEGIN TO MOVE WESTWARD.  OVER THE CENTRAL ATLC...A DEEP
LAYERED LOW APPROXIMATELY 600 NM SE OF BERMUDA NEAR 30N53W IS
THE PRIMARY WEATHER MAKER AGAIN TODAY. DIFFLUENT UPPER LEVEL
FLOW TO THE EAST OF THE LOW IS PRODUCING AN EXPANDING AREA OF
SCATTERED MODERATE CONVECTION ALONG AN OLD STATIONARY FRONT FROM
25N-33N BETWEEN 45W-53W.  FINALLY OVER THE E ATLC...THE PATTERN
CONTINUES TO BE RETROGRESSIVE AS A LARGE UPPER LOW NEAR 30N30W
MOVES WESTWARD.  STRONG SUBSIDENCE OVER THE CONFLUENT SIDE OF
THE UPPER LOW IS PRODUCING DRY/STABLE CONDITION WITHIN THE
MIDDLE AND UPPER PORTION OF THE ATMOSPHERE N OF THE ITCZ BUT
THERE IS JUST ENOUGH LOW LEVEL MOISTURE TO PRODUCE BROKEN
STRATOCUMULUS CLOUDS AND SHOWERS FROM 30W WESTWARD TO 45W.
CLOUDINESS SHARPLY DECREASES E OF 30W AS AN AREA SAHARAN DUST
HAS MADE ITS WAY OFF THE AFRICAN CONTINENT. FURTHER S...THE ITCZ
IS MOST ACTIVE BETWEEN 25W-45W AND FROM 50W-65W.

$$
FORMOSA


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