[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED APR 02 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 5N10W 2N20W 3N30W 1N40W CROSSING THE
EQUATOR NEAR 42W TO 2S45W. THE AXIS REMAINS ACTIVE TODAY WITH
SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 210 NM S
OF THE AXIS BETWEEN 10W-20W...WITHIN 240 NM S OF THE AXIS
BETWEEN 22W-28W AND WITHIN 240 NM N OF THE AXIS BETWEEN 28W-45W.

...DISCUSSION...

GULF OF MEXICO...
THE REGION CURRENTLY LIES IN A NW TO N MID-UPPER FLOW REGIME
...BETWEEN A LARGE RIDGE OVER THE TROPICAL EPAC AND AN AMPLIFIED
TROUGH OVER THE W ATLC AND THE CARIBBEAN. THIS PATTERN IS
PRODUCING MODESTLY DRY AIR OVER THE GULF...EXCEPT FOR SOME HIGH
LEVEL CLOUDINESS SPREADING OVER THE NW PORTION. AT THE SFC...A
SLOW MOVING OR STALLED FRONT IS DRAPED ACROSS THE DEEP SOUTH
FROM CENTRAL SOUTH CAROLINA TO THE NEW ORLEANS AREA THEN OFF THE
LOUISIANA COAST AND BACK INLAND OVER S TEXAS. MOST OF THE
ASSOCIATED OVERRUNNING MOISTURE IS INLAND OVER THE SRN STATES.
THIS BOUNDARY IS NOT EXPECTED TO MAKE MUCH FURTHER SE PROGRESS
DUE TO THE LACK OF UPPER SUPPORT. HOWEVER...THE NEXT BOUNDARY IS
ANTICIPATED TO BE STRONGER AND ENTER THE NW WATERS BY FRI NIGHT.
ELSEWHERE...LIGHT TO MODERATE ELY FLOW IS TRANSPORTING SCATTERED
SHOWERS AND ISOLATED TSTMS ACROSS THE FL STRAITS AND A SMALL
PORTION OF THE SE GULF.

CARIBBEAN SEA...
A LARGE AMPLIFIED MID-UPPER TROUGH EXTENDS ACROSS THE CENTRAL
AND WRN CARIBBEAN FROM THE BAHAMAS THRU THE WINDWARD PASSAGE TO
COSTA RICA. INSTABILITY ASSOCIATED WITH A VORTICITY MAXIMUM OVER
THE SRN BAHAMAS AND DIFFLUENCE TO THE E OF THE AXIS IS
GENERATING SCATTERED SHOWERS AND TSTMS N OF 17N BETWEEN 70W-78W.
DRY STABLE AIR...DUE TO CONFLUENCE ALOFT W OF THE AXIS...HAS
SPREAD WELL S FROM THE YUCATAN CHANNEL TO NRN COLOMBIA. IN THE
LOW LEVELS...A WEAK TROUGH CONTINUES TO TRACK QUICKLY WWD ALONG
75W. THIS FEATURE IS ENHANCING THE AFOREMENTIONED SHOWER/TSTM
ACTIVITY...WHICH IS MAINLY E OF THE SFC TROUGH AXIS SHEARED BY
STRONG WLY FLOW ALOFT. TRADE WINDS ARE STRONG E OF THE TROUGH
AXIS AND LIGHT TO MODERATE TO ITS W. AS A SIDE NOTE...THE
UW-CIMSS MIMIC-TPW PRODUCT REVEALS THE PROGRESS OF THE LOW-LEVEL
TROUGH WELL...WHICH IS LIKELY A COMBINATION OF SOME TROPICAL
MOISTURE AND A MID-LATITUDE SURGE THAT ROTATED AROUND THE
SUBTROPICAL RIDGE.

ATLANTIC OCEAN...
A SHORTWAVE UPPER TROUGH IS NEARLY CUT OFF OVER THE SRN BAHAMAS
WHILE ANOTHER SHORTWAVE SKIRTS THE N WATERS ALONG 77W. THE NRN
SHORTWAVE...COMBINED WITH A SFC TROUGH OFF THE FL E COAST ALONG
31N77W 27N79W...IS PRODUCING QUITE A BIT OF TSTM ACTIVITY.
LIGHTNING DATA IS VERY IMPRESSIVE SHOWING A SWATH OF STRIKES
FROM THE NW BAHAMAS NORTH-NORTHEASTWARD WITHIN 240 NM E OF THE
SFC TROUGH AXIS. LESS OF A LIGHTING DISPLAY IS OCCURRING IN
ASSOCIATION WITH THE SRN BROADER TROUGH S OF 23N BETWEEN
68W-75W. DEEP LAYER SUBSIDENT RIDGING LIES OVER THE CENTRAL
ATLC. THE TIGHT PRES GRADIENT...TO THE S OF THE RELATED 1032 MB
SFC HIGH NEAR 32N55W...IS PRODUCING STRONG TRADES S OF 25N AS
NOTED IN RECENT SCATTEROMETER DATA. WINDS ARE STRONGEST JUST W
OF A DYING COLD FRONT FROM 32N30W TO 25N35W CONTINUING TO
20N45W. A 1210Z ASCAT PASS SHOWS SOME EVIDENCE OF A WEAK SFC LOW
ALONG THE FRONT...WILL RE-EXAMINE FOR THE 18Z ANALYSIS. WHILE
DEEP MOISTURE IS MINIMAL ALONG THE FRONT THERE IS SOME
CONVECTIVE ACTIVITY CLIPPING THE N PORTION...N OF 29N BETWEEN
27W-29W RELATED TO THE UPPER TROUGH. IN THE TROPICS...A
SPRAWLING UPPER HIGH IS CENTERED NEAR 8N28W. DIFFLUENT FLOW TO
THE S OF THE HIGH IS ENHANCING CLUSTERS OF CONVECTION IN THE
ITCZ.

$$
CANGIALOSI






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