[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041103
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED APR 4 2007

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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N7W 2N17W ALONG THE EQUATOR FROM
23W-44W AND INTO SOUTH AMERICA NEAR 2S46W. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF THE AXIS FROM
16W-20W. CLUSTERS OF SIMILAR CONVECTION ARE FROM 4N TO S OF THE
EQUATOR E OF 20W ACROSS THE PRIME MERIDIAN...WITHIN 200 NM N OF
THE AXIS 23W-31W...AND FROM 3N TO THE EQUATOR FROM 42W-47W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDING FROM THE CARIBBEAN TO THE W ATLC
COVERS THE GULF AND CONTINUES TO ADVECT UPPER LEVEL MOISTURE
ACROSS MEXICO INTO THE GULF AND THE SE US. THE SHORT WAVE TROUGH
OVER E TEXAS/MEXICO IS BEING ABSORBED BY A LONG WAVE TROUGH OVER
THE CENTRAL PLAINS. THE UPPER TROUGH CONTINUES TO ENHANCE HEAVY
SHOWERS/THUNDERSTORMS OVER E MEXICO AND TEXAS INTO THE W GULF W
OF 92W. ASSOCIATED WITH THE UPPER TROUGH IS A FRONTAL BOUNDARY
EXTENDING INLAND OVER TEXAS WITH A SQUALL LINE MOVING S WELL
AHEAD OF THE FRONT. THE SQUALL LINE HAS HELD TOGETHER OVERNIGHT
AND AS OF 0915Z THE SQUALL LINE STRETCHED FROM CENTRAL GEORGIA
TO THE LOUISIANA/TEXAS BORDER NEAR 32N94W. THE SQUALL LINE IS
APPROACHING THE GULF PUSHING ISOLATED SHOWERS/THUNDERSTORMS
AHEAD OF THE MAIN LINE IN THE GULF WATERS. A WEAK SURFACE RIDGE
EXTENDS FROM THE W ATLC ACROSS THE GULF ANCHORED BY A HIGH JUST
NE OF THE BAHAMAS. THIS SURFACE RIDGE WILL GIVE WAY AS THE COLD
FRONT IS EXPECTED TO ENTER THE NW GULF LATER TODAY AND PASS
THROUGH THE AREA BY LATE THURSDAY WITH WINDS SHIFTING TO A
NORTHERLY DIRECTION AND INCREASING BEHIND THE FRONTAL PASSAGE.

CARIBBEAN SEA...
A BROAD UPPER E/W RIDGE EXTENDS ACROSS THE N PORTION OF SOUTH
AMERICA INTO THE W CARIBBEAN FROM COLOMBIA TO CUBA WITH SW WIND
TRANSPORTING UPPER LEVEL MOISTURE FROM THE E PACIFIC ACROSS
CENTRAL AMERICA INTO THE NW PORTION OF THE CARIBBEAN. LOWER
PRESSURES IN THE TROPICS CONTINUE TO PRODUCE MODERATE/STRONG
TRADE WINDS ACROSS THE BASIN EXCEPT IN THE NW WHERE LIGHTER
WINDS PREVAIL. MODERATE/STRONG SUBSIDENCE AND DRY AIR COVER MUCH
OF THE CARIBBEAN ESPECIALLY E OF 80W.

ATLANTIC OCEAN...
AN UPPER RIDGE/TROUGH/RIDGE PATTERN CONTINUES TO DOMINATE THE
FORECAST AREA. A BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN
INTO THE W ATLC W OF 65W. A SURFACE RIDGE COVERS THE W ATLC INTO
THE GULF OF MEXICO FROM 20N-30N W OF 65W ANCHORED BY A 1020 MB
HIGH NE OF THE BAHAMAS NEAR 27N76W. A DEEP LAYERED TROUGH IS IN
THE CENTRAL ATLC N OF 16N FROM 35W-65W WITH THE A SERIES OF
UPPER LOWS N OF THE REGION. THE ASSOCIATED LEADING FRONTAL
BOUNDARY HAS PULLED UP STATIONARY ENTERING THE E ATLC NEAR
32N23W EXTENDING SSW TO 22N34W CONTINUING SSW AS A SURFACE
TROUGH TO 17N39W. A 1002 MB LOW CENTERED NEAR 33N52W CONTINUES
TO DEEPEN WHILE EXTENDING A SECOND COLD FRONT SW INTO THE
W/CENTRAL ATLC ALONG 32N51W ALONG 28N58W THEN NE TO 30N67W. THIS
SYSTEM IS EXPECTED TO CONTINUE TO DEEPEN WHILE BEING ENTRAINED
AROUND THE MAIN LOW INCREASING SHOWER ACTIVITY WITH ASSOCIATED
STRONGER WINDS AND HIGH SEAS TO WELL WITHIN THE AREA. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90/120 NM SE OF THE
COLD FRONT. THE LEADING FRONT IS EMBEDDED WITHIN AN AREA OF
MODERATE SUBSIDENCE AND DRY UPPER AIR LIMITING SHOWER ACTIVITY.
BROAD E/W UPPER RIDGE COVERS THE TROPICAL ATLC EXTENDING FROM
AFRICA ACROSS THE ATLC TO SOUTH AMERICA WITH THE AXIS ROUGHLY
ALONG 7N/9N THUS SUPPRESSING THE ITCZ AXIS TO THE S. A SECOND
UPPER RIDGE AXIS EXTENDS FROM THE E/W RIDGE N ALONG 20W.

$$
WADDINGTON/WALLACE




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