[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201735
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAR 20 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 3N21W 2N38W TO THE EQ41W.
SCATTERED MODERATE CONVECTION IS WITHIN 150 NM N OF THE AXIS
BETWEEN 23W-30W. SIMILAR ACTIVITY IS WITHIN 90 NM N OF THE AXIS
BETWEEN 31W-43W AND S OF 2N W OF 47W.

...DISCUSSION...

GULF OF MEXICO...
THE MAIN STORY IN THE GULF IS THE MODERATE TO STRONG E-SE WINDS
PRODUCED BY A RATHER TIGHT PRES GRADIENT TO THE SE OF A STRONG
BERMUDA HIGH. THE STRONG ELY WINDS ARE ADVECTING PATCHES OF
SHALLOW MOISTURE ACROSS CENTRAL AND S FLA WHERE DOPPLER RADAR IS
DETECTING SOME PRECIP ECHOES. IN THE MID AND UPPER LEVELS...A
HIGHLY AMPLIFIED RIDGE IS MOSTLY N OF THE REGION WITH A WEAK
SHORTWAVE EXTENDING S ACROSS FLORIDA AND THE W BAHAMAS. THIS
PATTERN IS LEADING TO MODERATE DRY SINKING AIR ACROSS THE
GULF...EXCEPT FOR THE NW PORTION WHERE THERE IS A THIN AREA OF
HIGH CLOUDS. LITTLE CHANGE IS EXPECTED OVER THE NEXT COUPLE OF
DAYS AS THIS AREA REMAINS ON THE WRN PERIPHERY OF A STRONG SFC
HIGH PRES RIDGE.

CARIBBEAN...
IT'S A FAIRLY QUIET DAY ACROSS MOST OF THE CARIB UNDER MODERATE
DRY AIR AND SW TO WLY FLOW ALOFT ON THE NW PERIPHERY OF A BROAD
MID TO UPPER LEVEL RIDGE. THE TAIL END OF AN ATLC FRONTAL TROUGH
EXTENDS INTO THE WINDWARD PASSAGE. WHILE MOST OF THE SHOWER AND
TSTMS ARE N OF THE ISLANDS THERE IS SOME SCATTERED ACTIVITY OVER
JAMAICA...HAITI AND IN THE PASSAGE ENHANCED BY LOW-LEVEL
CONVERGENCE NEAR THE TROUGH. ELSEWHERE TYPICAL PATCHES OF LOW
AND MID LEVEL CLOUDS ARE BEING DRIVEN ACROSS THE SEA BY MODERATE
TO STRONG TRADES. THESE WINDS ARE POOLING SHALLOW MOISTURE OVER
HONDURAS AND BELIZE. LOOKING AHEAD A FEW DAYS...THE TRADES WILL
BEGIN TO SLACKEN WED NIGHT AS THE TROUGH IN THE ATLC WEAKENS.

WESTERN ATLANTIC...
THE MAIN AREA OF PRECIP IN THE ATLC BASIN IS ASSOCIATED WITH A
STALLED FRONTAL BOUNDARY ENTERING THE AREA NEAR 32N52W AND
STRETCHING SW ALONG 27N61W 22N69W. THE BOUNDARY CONTINUES SW
FROM THERE AS A SFC TROUGH TO THE WINDWARD PASSAGE. AN UPPER
LEVEL DIFFLUENT PATTERN ALONG WITH LOW-LEVEL CONVERGENT FLOW IS
PRODUCING A SWATH OF SHOWERS AND TSTMS WITHIN 180 NM EITHER SIDE
OF THE FRONT AND MORE ISOLATED ACTIVITY WITHIN 90 NM OF THE
TROUGH. MODELS SHOWS THIS BOUNDARY BECOMING FURTHER STRETCHED
INTO THE RIDGE TO ITS W AND WEAKENING OVER THE NEXT COUPLE DAYS.
SOME OF THE COMPUTER MODELS ARE HINTING AT A PIECE OF THE ENERGY
BREAKING OFF LATER THIS WEEK POSSIBLY BRINGING SOME UNSETTLED
WEATHER TO A SIMILAR REGION AS TODAY. ELSEWHERE HIGH PRES IS THE
THEME. THE RATHER TIGHT GRADIENT BETWEEN THE FRONT A 1033 MB
HIGH NEAR BERMUDA IS PRODUCING MODERATE TO STRONG E-NELY WINDS
ACROSS MUCH OF THE SW ATLC W OF THE FRONTAL TROUGH. THESE WINDS
ARE STEERING PATCHES OF SHALLOW MOISTURE ACROSS THE BAHAMAS AND
CENTRAL/SOUTH FLA. QUITE WINDY CONDITIONS AND ISOLATED SHOWERS
ARE LIKELY TO CONTINUE MUCH OF THE WEEK AS THE PRES GRAD REMAINS
TIGHT.

EASTERN ATLANTIC...
STRONG SFC HIGH PRES RIDGING IS ALSO THE THEME HERE SUPPORTED BY
A 1040 MB HIGH N OF THE AZORES. A VERY WEAK COMPACT 1014 MB LOW
IS LOCATED NEAR 24N20W. ONLY ISOLATED SHOWERS ARE NOTED WITHIN
90 NM N OF THIS OTHERWISE LOW-LEVEL CLOUD SWIRL. THE MAIN
STORY...SIMILAR TO THE WRN-MOST ATLC...IS THE STRONG NE-ELY
WINDS WHICH COVER A LARGE PORTION OF THE DISCUSSION AREA N OF
20N. IN THE MID AND UPPER LEVELS...A LARGE TROUGH HAS BEEN
CARVED OVER JUST ABOUT THE ENTIRE E ATLC WITH THE MAIN UPPER LOW
CENTERED JUST NW OF THE CANARY ISLANDS. THE ONLY WEATHER EFFECT
OF THIS TROUGH IS ON THE SE SIDE ACROSS THE DEEP TROPICS WHERE A
SWLY JET RACES FROM 14N32W ACROSS THE CAPE VERDE ISLANDS AND NRN
AFRICA. PATCHY UPPER LEVEL MOISTURE LIES TO THE RIGHT OF THE JET
AXIS WITH ENHANCED UPPER CONFLUENCE LEADING TO STRONG SINKING
AIR LEFT OF THE AXIS. THE DIVERGENT PATTERN ALOFT TO THE E OF
THE JET IS PROVIDING A FAVORABLE ENVIRONMENT FOR CONVECTION IN
THE ITCZ.

$$
CANGIALOSI




This weather bulletin was brought to you by:
www.nashvilleweather.net