[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200531
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN 20 MAR 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 0345 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 3N20W 4N31W 1N39W THEN ALONG
THE EQUATOR TO THE COAST OF SOUTH AMERICA. SCATTERED/NUMEROUS
STRONG CONVECTION IS WITHIN 75 NM OF LINE 2N9W-5N12W. CLUSTERS
OF SCATTERED STRONG CONVECTION ARE WITHIN 120/150 NM OF THE
AXIS FROM 10W-22W AND FROM THE EQUATOR TO INLAND OVER AFRICA E
OF 10W ACROSS THE PRIME MERIDIAN. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE S OF 10N FROM 35W-53W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYERED TROUGH COVERS THE GULF WITH YET ANOTHER POTENT S
STREAM SHORTWAVE DISTURBANCE MOVING E ACROSS TEXAS INTO THE SE
UNITED STATES AND IS THE CURRENT WEATHER MAKER AS IT MOVES INTO
THE GULF. ATTENDANT FRONTAL BOUNDARY IS STILL INLAND OVER THE
MISSISSIPPI VALLEY THROUGH TEXAS AND WILL BE IN THE GULF BY
LATER THIS MORNING. WEAK SURFACE RIDGE PREVAILS OVER THE E HALF
OF THE GULF AND FLORIDA WITH A 1020 MB HIGH CENTERED ALONG THE
NW COAST OF FLORIDA NEAR 29N84W. GENERALLY COOL/DRY CONDITIONS
PREVAIL ACROSS THE E GULF COURTESY OF THE CONTINENTAL AIRMASS.
STRONG SHOWERS/THUNDERSTORMS ARE INLAND OVER N LOUISIANA AND E
TEXAS WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NW
GULF N OF 27N W OF 93W. THE SHORTWAVE AND ASSOCIATED SHOWER/
THUNDERSTORM ACTIVITY SHOULD MOVE INTO THE CENTRAL GULF LATER
TODAY. THEREAFTER...THE PROGRESSION OF THE PATTERN BECOMES A
LITTLE LESS CERTAIN WITH SOME DIFFERENCES IN THE NUMERICAL
MODELS. NONETHELESS...UNSETTLED/WET CONDITIONS MAY EXIST OVER
THE E GULF AND FLORIDA MONDAY INTO TUE.

CARIBBEAN...
PERSISTENT MID/UPPER LEVEL RIDGE REMAINS ANCHORED ACROSS THE
AREA EXTENDING EXTENDING E/W ALONG 15N. THERE IS A LITTLE UPPER
LEVEL MOISTURE MOVING AROUND THE W PERIPHERY OF THE RIDGE OVER
CENTRAL AMERICA AND THE W CARIBBEAN. HOWEVER...MOST OF THE AREA
CONTINUES TO BE DOMINATED BY STRONG SUBSIDENCE AND DRY/STABLE
CONDITIONS ALOFT. DRY CONDITIONS ALSO PREVAIL IN THE LOWER
LEVELS LIMITING SHOWER ACTIVITY SAVE SOME ISOLATED ACTIVITY
ALONG A REMNANT STATIONARY FRONT FROM THE E TIP OF CUBA TO
CENTRAL AMERICA NEAR THE HONDURAS/NICARAGUA BORDER. THE BULK OF
THIS ACTIVITY IS FOCUSED NEAR THE S EXTENT OF THE BOUNDARY OVER
CENTRAL AMERICA. MOISTURE WILL REMAIN PRIMARILY LIMITED OVER
MOST OF THE AREA THROUGH THE WEEKEND MAINTAINING THE VERY DRY
PATTERN WHICH HAS PREVAILED FOR SEVERAL WEEKS.

ATLANTIC...
STRONG MID/UPPER LEVEL RIDGING OVER THE CARIBBEAN WATERS IS
PRODUCING MAINLY W/WSW FLOW OVER THE W ATLC...WITH A WEAK TROUGH
N OF 30N OVER THE CENTRAL ATLC. ATTENDANT COLD FRONT EXTENDS SW
FROM A 1002 MB LOW N OF THE AREA NEAR 34N40W ALONG 28N52W TO
25N62W THEN DISSIPATING STATIONARY TO THE E TIP OF CUBA. MOST OF
THE UPPER LEVEL DYNAMICS/SUPPORT WITH THIS SYSTEM IS FOCUSED
WELL N OF THE AREA BUT LOW LEVEL MOISTURE POOLING IS PRODUCING A
NARROW BAND OF ISOLATED SHOWERS EXTEND UP TO 120 NM SE OF THE
COLD FRONT. BEHIND THE FRONT...BROKEN COLD AIR STRATOCUMULUS
CLOUDS TO THE SE UNITED STATES COAST WHERE A 1013 MB LOW OFF THE
SOUTH CAROLINA COAST NEAR 32N77W IS PRODUCING SCATTERED SHOWERS
N OF 31N W OF BERMUDA. FURTHER E...AN ELONGATED E/W SFC RIDGE
SPANS ACROSS MUCH OF THE CNTRL/ERN ATLC FROM JUST NE OF THE
LEEWARD ISLANDS TO THE AFRICAN COAST ALONG 20N...WITH A 1019 MB
HIGH NE OF THE LEEWARD ISLANDS NEAR 20N60W AND A 1020 MB HIGH
NEAR 20N43W. A TIGHT PRESSURE GRADIENT ALONG THE N PERIPHERY OF
THE RIDGE IS PRODUCING MODERATE/STRONG W WINDS N OF 26N BETWEEN
20W-50W. THERE IS VIRTUALLY NO LARGE-SCALE PRECIPITATION OVER
THE E HALF OF THE SUBTROPICAL ATLC. FURTHER S...MODERATE
SUBSIDENCE IN THE UPPER LEVELS AND DRY AIR IN THE LOWER LEVELS
MOVING OFF W AFRICA IS LARGELY SUPPRESSING CLOUDS AND
PRECIPITATION OVER THE N PORTION OF THE TROPICAL ATLC.

$$
WALLACE


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