[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAY 15 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 24W/25W S OF 11N MOVING W 10-15 KT.
SATELLITE IMAGERY SHOWS A BROAD AREA OF LOW LEVEL CYCLONIC
TURNING ALONG THE WAVE NEAR 5N. SCATTERED SHOWERS AND TSTMS ARE
WITHIN 200 NM AHEAD OF THE WAVE AXIS. MORE SHOWER AND TSTM
ACTIVITY IS OBSERVED BEHIND THE WAVE AXIS FROM 2N-10N BETWEEN
15W AND 22W. THIS CONVECTIVE ACTIVITY IS BEING ENHANCED BY UPPER
DIFFLUENCE ASSOCIATED WITH AN UPPER-LEVEL HIGH LOCATED NEAR
9N18W.

A TROPICAL WAVE IS ALONG 48W S OF 11N MOVING W 10-15 KT. AN
INVERTED-V PATTERN IS PRETTY WELL DEFINED ON SATELLITE IMAGERY
WITH SOME LOW-LEVEL CYCLONIC TURNING ALONG THE WAVE AXIS NEAR
7N. SCATTERED SHOWERS AND TSTMS ARE WITHIN 160 NM EITHER SIDE OF
THE AXIS S OF 8N. THE SSMI-DERIVED TOTAL PRECIPITABLE WATER
PRODUCT FROM CIMSS SUPPORTS THE POSITION OF THE WAVE.

THE THIRD TROPICAL WAVE IS OVER WESTERN VENEZUELA/EASTERN
COLOMBIA WITH IT AXIS ALONG 71W/72W. A SMALL BULGE OF MOISTURE
ON THE MIMIC TPW ANIMATION BETWEEN THE ABC ISLANDS AND THE
GUAJIRA PENINSULA CONFIRMS THE PRESENCE OF THIS WAVE THAT IS
ENHANCING SOME SHOWER/TSTM ACTIVITY ACROSS THE AREA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 7N23W 5N26W 3N36W 5N47W.
CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER SIERRA LEONE
AND GUINEA. THE REST OF THE CONVECTIVE ACTIVITY IS MAINLY
ASSOCIATED WITH THE TROPICAL WAVES PREVIOUSLY DESCRIBED.

...DISCUSSION...

GULF OF MEXICO...
THE GULF REMAINS UNDER THE INFLUENCE OF A RIDGE...BOTH AT THE
SURFACE AND ALOFT. A COASTAL TROUGH IS ON THE 21Z MAP EXTENDING
FROM 27N96W TO NEAR TAMPICO MEXICO. THIS PATTERN IS PRODUCING
SOUTHERLY WINDS OF 15 TO 20 KT OVER MOST OF THE GULF. A COLD
FRONT IS CURRENTLY MOVING OFF THE TEXAS COAST. THE FRONT WILL
EXTEND FROM NORTH FLORIDA TO NEAR 25N91W TO BAY OF CAMPECHE
FRIDAY NIGHT AND BECOME STATIONARY AND WEAKEN ON SATURDAY. AHEAD
OF THE FRONT...A SQUALL LINE IS MOVING EWD ACROSS THE FLORIDA
PANHANDLE. IN THE UPPER LEVELS...A LARGE UPPER HIGH CENTERED
OVER THE NW CARIBBEAN DOMINATES THE ENTIRE GULF REGION AND THE
STATE OF FLORIDA WHILE A DEEP LAYERED TROUGH IS OVER THE SW
CONUS AND MEXICO. SWLY AND THEN WLY WINDS BETWEEN THESE TWO
UPPER LEVEL FEATURES ARE TRANSPORTING ABUNDANT UPPER LEVEL
MOISTURE FROM THE EPAC THROUGH MEXICO INTO THE NORTHERN GULF
WATERS.

CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT FROM THE CENTRAL ATLC REMAINS WELL
DEFINED ACROSS HISPANIOLA AND JAMAICA WHERE IT IS PRODUCING
BROKEN LOW/MID CLOUDS AND MAINLY LIGHT SHOWERS. THE REMAINDER
OF THE BASIN IS PRETTY QUIET DUE TO THE PRESENCE OF A MID/UPPER
RIDGE OVER THE WEST AND CENTRAL CARIBBEAN AND UPPER TROUGHING
OVER THE E CARIBBEAN. THIS UPPER PATTERN IS PRODUCING MODERATE
TO STRONG SUBSIDENCE SUPPRESSING THE DEVELOPMENT OF ANY
SIGNIFICANT CONVECTION. A PLUME OF TRANSVERSE HIGH CLOUDS IS
OVER THE SW CARIBBEAN. CONVECTION HAS DEVELOPED AGAIN EARLY THIS
EVENING NEAR THE COLOMBIA/PANAMA BORDER DUE TO THE CLOSE
PROXIMITY OF THE EPAC ITCZ. WEAK HIGH PRES N OF THE AREA
COMBINED WITH THE ABOVE MENTIONED FRONTAL SYSTEM IS PRODUCING
FAIRLY MODEST TRADE WINDS ACROSS THE REGION. THESE WINDS ARE
EXPECTED TO INCREASE SLIGHTLY DURING THE UPCOMING WEEKEND AS THE
ATLC RIDGE EXTENDS WWD ACROSS THE BASIN.

ATLANTIC OCEAN...
AN UPPER-LEVEL TROUGH OVER THE CENTRAL ATLC SUPPORTS A COLD
FRONT THAT EXTENDS FROM A 1010 MB LOW NEAR 33N56W TO HISPANIOLA.
LOW-LEVEL CONVERGENCE ALONG THE FRONTAL BOUNDARY COUPLED WITH A
DIFFLUENT PATTERN ALOFT IS PRODUCING A 200 NM WIDE BAND OF
SCATTERED SHOWERS AND TSTMS E OF THE FRONT N OF 24N. A 1022 MB
HIGH PRES LOCATED NEAR 31N75W IS BEHIND THE FRONT PRODUCING
MOSTLY FAIR WEATHER ACROSS THE BAHAMAS. THIS HIGH IS FORECAST TO
MOVE ESE OVER THE W ATLC DURING THE NEXT 24 HOURS.
THE REMAINDER OF THE CENTRAL AND E ATLC IS DOMINATED BY A 1024
MB SFC HIGH LOCATED NEAR 33N40W. THE TIGHT PRES PATTERN BETWEEN
THE HIGH AND THE AFOREMENTIONED FRONT IS PRODUCING SLY WINDS OF
20-30 KT WITHIN 300 NM E OF THE COLD FRONT N OF 23N. IN THE
UPPER LEVELS...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES DE
DISCUSSION AREA. IN THE DEEP TROPICS...AN ELONGATED RIDGE
REMAINS BETWEEN AFRICA AND THE WINDWARD ISLANDS ENHANCING
CONVECTION ALONG THE ITCZ.

$$
GR





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